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Biological Sciences Program
BSCI 201
Justicia Opoku

EXAM 1 NOTES 11/20/2013 8/31 KingdomAnimalia- man is part of animal kingdom- top grouping Anatomy: study of the parts of the body and how they relate to each other Gross/Macroscopic: study of large body parts visible to naked eye Regional: all structures in particular region of body Systematic: structure of the body are studied by systems Microscopic: very small structures that are viewed by microscopes not the naked eye Cytology: cells viewed Histology: tissues viewed Developmental: structural changes that occur in body throughout the life span Need all organ systems working in unison Cell form communities Tissues are made up of group of similar cells to perform specific role ComparativeAnatomy: compare different structures /organs of the body Anatomy Study success 1. observation 2. manipulation 3. master terms Anatomical position 1. body erect 2. feet slight apart 3. palms face forward 4. thumbs away from body Planes/Sections Frontal: vertical cut= divides body into anterior and posterior Sagittal: vertical cut=divides body into left/right parts Midsagittal: cut exactly in mid line that divides body into EQUAL left/right parts Anatomy 9/2 -body has to be in anatomical position for dissection -2 cavities in body trunk: dorsal and ventral cavities -see these two cavities by frontal cut -dorsal: spinal cord and brain -ventral: larger cavity and subdivided into superior thoracic cavity and inferior abdominopelvic cavity -ventral is divided by diaphragm -Thoracic cavity: contains heart and lungs -Abdominal cavity: contains digestive organs -ventral cavity surrounded by serous membrane -each organ has its own compartment, which prevents spread of infection -Compartmentalization allows each organ in the body cavity to be surrounded by its own membrane -organs in dorsal cavity are surrounded by membranes called meninges (inflammation of meninges= meningitis) -dorsal cavity is composed of the cranial cavity= houses the brain; and the vertebral cavity= houses the spinal cord -Ventral Cavity 1. Superior Thoracic Cavity 2. Inferior Abdominopelvic Cavity -these are divided by the diaphragm -membranes called serous membranes surround organs in the ventral body cavity Advantages of Compartmentalization 1. prevents the spread of infection from one organ to another in same body cavity 2. prevents interference of the functioning of each organ by neighboring organs in the same body cavity 9 division of abdominopelvic cavity, but a simpler way is the 4 quadrants (right/left upper and lower) Abdominal cavity and pelvic cavity blend in so you can’t divide them Physiology: study of the function of the body parts -structure defines function 1. Systemic physiology: study of the function of the systems body 11 organ systems in body and all 11 organ systems work together to sustain the human body, referred to as HOMEOSTASIS if one organ system isn’t working it is homeostatic imbalance if one system fails and not repaired other systems will fall apart 11 systems: integumentary, skeletal, muscular, nervous, endocrine, cardiovascular, lymphatic, respiratory, digestive, urinary, reproductive talk about endocrine system when there in a body imbalance Levels of structural organization 1. Chemical- atoms combine to form molecules 2. Cellular- cells made up of molecules 3. Tissue- tissues made up of similar types of cells 4.. Organ- organs made up of different types of tissues 5. Organ system- consists of different organs that work together closely 6. Organismal- organisms made up of many systems HOMEOSTASIS: balance in the body -established by 2 regulatory organ systems: nervous and endocrine -nervous system: fast action, short-lived and localized -endocrine system: generally slow action, long lasting and global (release hormones in the blood stream) Homeostasis imbalance=DISEASES -a quick adjustment use the nervous system Chapter 2: Chemical Level (lowest level) -looking at structural organization in the human body (6 structural levels) -Chemical level is the LOWEST -means were looking at the biochemical reactions occurring in the body -these chemical reactions are what we refer to as physiological processes necessary to sustain life -matter: anything that occupies space and has mass; composed of elements -atoms=building blocks of all matter -112 elements; most important: CARBON, NITROGEN, OXYGEN, HYDROGEN Structure of an atom: 1. protons: positively charged- in the nucleus and is referred to as ATOMIC # 2. neutrons: neutral in nucleus therefore nucleus is POSITIVE 3. elections: negatively charged in outer shells 9/7 electrons are located/arranged in the orbits/shells in a specific manner first shell: max 2 electrons second shell: max 8 electrons third shell: max 18 electrons however stable with 8 electrons outermost shell is VALENCE shell if valence shell does not contain max number of electrons, the atom is UNSTABLE and therefore chemical reactive atoms are not happy unless shells are full achieve stability in 2 ways lose electrons or gain electrons inert elements: atoms with valence shells complete and therefore chemically inert, unreactive ex: atom with 10 electrons, 2 in first and 8 in 2 so therefore stable noble gases chemically-reactive elements: atoms in the elements that have incomplete valence shells and therefore unstable and chemically reactive achieve stability thorough forming CHEMICAL BONDS with other atoms using their valence electrons- results in formation of molecules and compounds 3 types of chemical bonds covalent bonds: electrons shared between atoms to attain stability nonpolar: shared equally ex: CO2 polar: UNEQUAL; one atom pulls the shared electrons closer to itself= ELECTRONEGATIVE and the other atom is ELECTROPOSITIVE oxygen: electronegative; hydrogen=electropositive ionic bonds: complete transfer of electrons ex: Na+ Cl- no longer an atom if gain/lose electron gaining/losing takes energy so is it easier to lose 7 or gain 1 to attain stability? Atom losing electron is CATION (positive) and atom accepting electron isANION (negative) Hydrogen bonds: wear bond between hydrogen atoms (electropositive) and electronegative ions Polar covalent compound Hydrogen bond= weakest; ionic b/c complete transfer; polar covalent b/c unequal share; nonpolar covalent b/c equal sharing Inorganic and Organic Compounds Inorganic: DON’T contain carbon (except carbon monoxide and carbon dioxide)= water, acids, bases, salts Organic: contain carbon that are covalently bonded Ex: carbs, lipids, proteins, nucleic acids Water- polar covalent molecule Most abundant compound in body- 70% of the volume of cells Known as universal solvent; involved in all biochemical reactions occurring in body High heat capacity-absorbs body heat High heat of vaporization: water evaporates from body using large amounts of heat-cools the body For cushioning around body organs such as the brain Acids and Bases Acids: substances that release hydrogen ions (H+)= protons. Hence, acids are also known as proton donors ex: HCL, H2CO3 Negative log of the H+ concentration= pH The H+ concentration is inversely proportional to the pH; the higher the H+ concentration, the lower the pH and vice versa Blood pH is strictly maintained between 7.35-7.45 (slightly above neutral pH)- the optimum pH for the actions of enzymes involved in the physiological processes High pH=low acidity, vice versa Bases- substances that accept H+, proton acceptors Ex: HCO3-, NaOH Acid-base balance is regulated by buffers-chemicals that resist abrupt changes in pH by binding H+ when the pH falls and by releasing H+ when the pH rises Salts are ionic compounds that dissociate completely in water to give cations and anions Organic Compounds Carbs: monosaccharide, disaccharides, poly…look at PowerPoint Huge role in digestion Lipids: neutral fats (triglycerides) phospholipids, steroids, Proteins: fibrous and globular proteins Nucleic acids: DNAand RNA Carbohydrates- hydrated carbons Monosaccharide=general formula sweet/soluble in water Monomers of carbohydrates Hexose (CH2O)6- glucose, fructose, galactose Pentose=(CH2O)5- deoxyribose, ribose Disaccharides- compose of 2 hexose sugars; sweet and soluble in water Maltose (grain sugar)- glucose and glucose Sucrose (table sugar)- glucose and fructose Lactose (milk sugar)- glucose and galactose If lactose intolerant don’t have lactase to break down lactose into the 2 monosaccharides Polysacchardies are broken up into disaccharides for digestion Long chains of glucose Storage form of glucose starch in plant cells GLYCOGEN in animal cells Insoluble in water and not sweet Lipids Hydrophobic (insoluble in water) 4 types Neutral fats=triglyceride Most abundant form of fat in human diet Known as Fats when solid and oils when liquids 2 types: saturated and unsaturated unsaturated: at least one double covalent bond in the carbon chain; liquid at room temp; plant sources saturated: single covalent bonds exist between all the carbons in the chain; solid at room temp; animal sources-butter Saturated fats increase LDL which increases strokes and heart attacks Better to have unsaturated than saturated 3 types of Lipoproteins vLDL= very low density lipoprotein LDL= low density lipoprotein= BAD CHOLESTEROL High content of cholesterol HDL= high density lipoproteins=GOOD Carry cholesterol from blood to liver where it will be eliminated from the body Need cholesterol Maintain the structure of the plasma membrane Synthesis of the steroid hormones: need these to establish homeostasis and reproduction The human body can synthesize 85% of the cholesterol needed Have to supplement via the diet 15% Any excess cholesterol in the body carried by LDL will cause plagues to deposit in the internal walls of the blood vessels:ATHEROSCLEROTIC plagues= condition ofATHEROSCLEROSIS ATHEROSCLEROSIS can lead to hypertension---chronic increase in blood pressure Hypertension will lead to congestive heart failure Atherosclerosis plaque formation is smaller blood vessels-smallest blood vessels in the human body 1. Cerebral blood vessels 2. Coronary blood vessels Plaque formation in these blood vessels can cause occlusion of these blood vessels= no blood flow; tissues served by the occluded vessels die Occlusion of cerebral blood vessels= ISCHEMIC STROKES= brain attack Occlusion of coronary blood vessels= MYOCARDIAL INFARCTION= “heart attack” This all explains why LDL is referred to as the bad cholesterol HDL: good cholesterol Cholesterol transported by HDL to the liver Cholesterol is degraded and eliminated from the body Lowers cholesterol level in the blood vessels Decreases chances of developing atherosclerotic plagues Phospholipids: polar head and 2 nonpolar tails Polar heads= hydrophilic, tails=hydrophobic Make up the membrane: non polar tails form the core of the plasma membrane Form micelles to transport hydrophobic neutral fats in the aqueous environment in the intestinal lumen Steroids: derived from cholesterol Eicosanoids-derived from arachidonic acids Proteins Building blocks of proteins areAMINOACIDS Each amino acid has anAMINO terminal that can act as a base and a CARBOXYL terminal that can act as an acid Amino acids are amphoteric molecules – can act as acids and bases 20 naturally occurring amino acids essential amino acids: must be ingested in the diet non-essential amino acids: the cells are capable of synthesizing these amino acids via a process known as TRANSAMINATION use amino acids in translation to make proteins 4 structure levels primary structure: linear polypeptide chain indicate the type and position of amino acid secondary structure: 2 types alpha HELIX coiled: coiled polypeptide chain beta PLEATED sheet: polypeptide chains linked side by side tertiary structure: secondary structure folded upon themselves to give a compact, globular molecule---3 dimensional Quaternary structure: 2 or more polypeptide chains are held together by disulfide bonds Ex: hemoglobin; insulin 2 Classes of Proteins Fibrous proteins Extended/ strand-like Insoluble in water Form the framework of all cells: structural proteins Provide mechanical and support and tensile strength as the main building material in the body Don’t denature Ex: collagen Globular Proteins Compact/ball-like Soluble in water, sensitive to pH and temp change Chemically active- mediate all biochemical reactions occurring in the body Functional proteins Ex: enzymes Are denatured (irreversibly damaged/destroyed) by low pH and high temperatures NucleicAcids RNA: ribonucleic acid Contains the pentose sugar called ribose DNA: deoxyribonucleic acid Contains the pentose sugar called deoxyribose Transcription Largest organic compounds in the body Cellular Level Cell Theory Cell is the basic structural and functional unit of all organisms According to the PRINCIPLE OF COMPLEMNTARITY of structure and function, the biochemical reactions occurring in a cell are dictated by the subcellular structures present in the cell Reproduction has a cellular basis 200 types of cells in the body with specific functions Cell diversity: different shapes/sizes Cells that connect body parts, form linings or transport gases: epithelial cells, fibroblasts Cells that move organs and body parts: muscle cells Cells that store nutrients: fat cell Cell that fights disease: macrophage Cell of reproduction : sperm Cell that gathers info and controls body functions: nerve cell 3 main parts of cell plasma membrane: defines the boundary of a cell very thin composed of 2 layers of phospholipids (lipid bilayer) arranged tail to tail with the polar hydrophilic heads exposed to the aqueous extracellular fluid and the intracellular fluid embedded membrane proteins and cholesterol are in constant flux : fluidity FLUID MOSAIC MODEL Cholesterol insert between the phospholipids tails to stabilize the plasma membrane= maintains the integrity of the plasma membrane 2 types of plasma membrane proteins 1. Integral proteins span the plasma membrane exposed on one surface or both surfaces of the membrane exposed on both surfaces: TRANSMEMBRANE proteins 2. Peripheral proteins attached to integral proteins of the phospholipids’heads on the cytoplasmic face of the plasma membrane These membrane proteins act as transporters- bring polar molecules across the membrane receptors-span the plasma membrane for neurotransmitters and hormones enzymatic activity intercellular joining cell-cell recognition: glycoprotein act as ID tags that are specifically recognized by other cells on the extracellular surface of cells, accumulation of glycoprotein and glycolipids form a structure called the GLYCOCALYX glycoprotein= membrane protein+ carbohydrates the pattern of carbohydrate arrangement is unique to each cell type. Hence, the glycocalyx acts as a molecular (biological) marker for cell-cell recognition EX: the glycocalyx on the surface of the ovum (egg) is recognized by the sperm—sperm approaches the ovum to bind Sudden changes in the pattern of the carbohydrate arrangement in the glycocalyx indicates the cells are turning cancerous 3 Membrane Junctions exist between adjacent cells in a tissue 1. Tight junction integral proteins of adjacent cells fuse to form an impermeable junction between cells can only take things across EX: blood brain barrier between the blood in capillaries and the neurons in the brain---BBB prevents the exposure of these neurons to toxins EX: cells lining the gastric wall (tight junctions prevent seeping) 2. Desmosome linker proteins inserted in the space between the adjacent cells to hold the cells together prevents cells from pulling apart under stress ANCHOR CELLS:ANCHORING JUNCTION Abundant in areas of the body subjected to stress Present in epidermis of the skin EX: heart wall: cardiac muscle 3. Gap junction transmembrane proteins called CONNEXONS: hollow cylindrical tubes that connect adjacent cells connexons act as channels to allow for the rapid transfer of ions for the rapid transfer of electrical current from cell to cell referred to as COMMUNICATING junctions present in cells that are electrically coupled and contract as a single unit: functional syncytium electrically coupled tissue functions as a single unit: all cells contract almost at the same time ex: smooth muscle MEMBRANE TRANSPORT: Plasma membrane is a selective barrier Passive process: substances cross the membrane without any energy input 1. Diffusion 3 subtypes Simple diffusion: hydrophobic/nonpolar/ lipid soluble substances easily diffuse through the lipid bilayer of the plasma membrane down their concentration gradient diffuse from areas of HIGHER concentration to areas of LOWER EX: O2 diffuses from the fluid outside the cell into the cell and CO2 diffuses from cell interior to the cell exterior Facilitated diffusion: involves carrier proteins: integral proteins imbedded in the plasma membrane Lipid insoluble/polar/hydrophilic substances are carried across the lipid bilayer of the plasma membrane EX: glucose and amino acids use facilitated diffusion to move into the cell Carrier proteins: once they are engaged in transporting the substance; transport maximum is reached: SATURATION: represented graphically by the sigmoid curve Osmosis: water will move from an area of lower solute concentration to an area of higher solute concentration 2. Filtration a passive process- no energy input movement of solution from area of higher pressure to area of lower pressure; down a pressure gradient Active Processes: cell provides energy (ATP) required to move substances across the membrane 1. Active transport: movement of solutes/ions from area of lower solute concentration to area of higher solute concentration (against concentration gradient) mediated by carrier proteins exhibits saturation and specificity “SOLUTE PUMPING” 2. Vesicular transport exocytosis : movement of substances out of the cell (enclosed in vesicle) secretory cells use exocytosis to secrete their content to the cells’exterior ex: hormones and enzymes are secreted this way endocytosis: movement of substances into the cell phagocytosis: movement of solid particles from the exterior into the interior; enclosed in vesicles: PHAGOSOMES lysosomes (cytosplasmic organelles that contain powerful digestive enzymes called LYSOZYMES) fuse with the phagosomes to digest it and its contents cells that perform phagocytosis: PHAGOCYTES phagocytes are present in the immune system (destroy pathogens: disease causing micro- organisms) ultimate phagocyte: MACROPHAGE may be clumps of bacteria or cell debris not all cells are capable of this pinocystosis: movement of solution into cells by enclosing the solution in vesicles bulk phase endocytosis all cells go through pinocytosis to obtain nutrients receptor-mediated endocytosis: receptors bind to specific substances and are taken into the cell LDL binds to LDL receptors on the plasma membrane of steroidgenic cells (cells that produce steroid hormones) Exhibits specificity and saturation Endocytosis and Exocytosis Trancytosis: Movements of substances enclosed in caveolae into a cell, across the cell and released on the opposite side of the cell via exocytosis Vesicular Trafficking: Intracellular movement of substances in coatmer- coated vesicles from organelle to organelle within the cell Resting Membrane Potential (RMP) Plasma membrane is very receptive to potassium ions More potassium ions inside and more sodium outside More potassium ions leave the cell than sodium ions coming in because plasma membrane is more permeable to potassium ions Therefore cytoplasmic surface is negative Separation of charges causes the RMP TONICITY Movement of water in and out of cells can shape or tone of cells Isotonic: concentration of solution inside and outside of the cells is the same; same amount of water moves in and outs; shape remains the same Hypertonic: Hypotonic: placed in solution with a lower concentration than solution inside cells; water moves via osmosis into the cells- cells swell and eventually burst Cytoplasm- the interior of the cell between the plasma membrane and the nucleus; contain cytoplasmic organelles Contains cytosol, cytoplasmic organelles and inclusions (not all cells have these) Membranous organelles Mitochondria Double membrane enclosing a fluid matrix (outer and inner membrane) Inner membrane contains cristae Contains own DNA: self-replicating organelle ER Smooth ER: lipid transport, lipid metabolism, lipid synthesis steroidgenic cells have prominent smooth ER which is the site of the synthesis of steroid hormones specialized smooth ER is muscle cells is called sarcoplasmic reticulum which is specialized to store and release calcium ions (ca2+) enzymes on smooth ER are involved in detoxification liver cells (hepatocytes) and kidney cells have prominent smooth ER--- site of detoxification of drugs Rough ER •external surface is studded with ribosomes ( Bound ribosomes) – these ribosomes synthesize the plasma protein and secretory proteins. Rough ER is therefore abundant in secretory cells such as liver cells •Rough ER is referred to as the “Membrane factory” because the synthesis of integral proteins and phospholipids in plasma membranes is associated with the rough ER Golgi apparatus TRAFFIC DIRECTOR OF CELL Composed of stacked/flattened membranous sacs Receives proteins/lipid from rough ER: these proteins may be modified All proteins received are packaged into vesicles and tagged for their destinations 3 types of vesicles 1. Secretory vesicles: contains proteins released via extocytosis secretory cells---secrete proteins---will have prominent rough ER and golgi apparatus; abundance of bound ribosomes 2. Vesicles that contain integral proteins and lipids destined for the plasma membrane to be incorporated into the plasma membrane Vesicles containing powerful digestive enzymes that remain in the cell= LYSOSOMES Lysosomes (spherical membranous organelles) Vesicles formed by the golgi apparatus—bud off from golgi Contain powerful digestive enzymes(LYSOZYMES) that digest vesicles and biological molecules Digest nonuseful tissues, worn-out organelles, worn-out cells Digest phagosomes hence, lysosomes are abundant in phagocytes Stimulate glycogenolysis : break down of glycogen into glucose 6 phosphates which will then enter into the glycolytic pathway Lysozymes in lysosomes stimulate bone resorption (bone breakdown) to release stored calcium back into the blood DEMOLITION CREW Short life span (die after 2 years) Peroxisomes Also spherical Membranous sacs that contain powerful enzymes that neutralize harmful free radicals (very unstable and seek to bond to other molecules to achieve stability) Free radicals are thought to play a role in the aging process 2 enzymes: Oxidases and Catalases more peroxisomes you have, the better Free radicals (harmful) + Oxidases Hydrogen Peroxide( harmful) Hydrogen peroxide + catalase water Nonmembranous organelles Ribosomes Free Ribsomes: float freely in cytosol and synthesize proteins that stay in the cell Bound ribosomes: bound to surface of rough ER and synthesize proteins that are transported to the plasma membrane and exported out of the cell Cytoskeleton “cell skeleton”- support other cytoplasmic organelles and allow for movements rod-like structures 3 types based on function 1. Microtubules: largest diameter= 25 nm wide made up of globular proteins called TUBULINS Tubulins are assembled into microtubules in the CENTROSOME: microtubule organizing center Centrosome contains 2 centrioles at right angles Each centriole is composed of 9 triplet array of microtubules Centrioles sprout spindle fibers required for cell division Centrioles form 2 types of cell extensions: CILIAAND FLAGELLUM Cilia: cellular extensions that occur in large numbers on the apical (exposed) surface of cells Cilia beat to create a current to move substances across the surface of the cells Flagellum: a single, longer cellular extension that beats to propel the cell it extends from: ONLY SPERM Structural difference between cilia and the flagellum: cilia has shorter extension and occurs in large numbers; flagellum has longer extension and only one per cell serve as “tracks” to transport intracellular substances involved in vesicular trafficking 2. Intermediate Filaments= 10 nm most stable type of cytoskeleton tough, insoluble fibrous fibers provide tensile strength to cells by resisting pulling forces placed on the cells 3. Microfilaments: smallest diameter= 7 nm arrangement is unique to each cell involved in formation of cleavage furrow during cytokinesis involved in the changes of the plasma membrane during endocytosis and exocytosis Nucleus: contains the genes which control activities of the cell Acell with one nucleus = Uninucleate Acell with many nuclei = Multinucleate Acell without a nucleus =Anucleate 3 main regions: Nuclear envelope (membrane) Double-layered selective membrane Similar to plasma membrane but the plasma membrane has GLYCOCALYX and the nuclear envelope has nuclear pore Nuclear pores allow molecules to enter/exit the nucleus RNAmove from nucleus to cytoplasm Nucleolus Synthesizes ribosomal RNA(rRNA) Each ribosomal subunit is composed of rRNAand protein rRNAis exported via the nuclear pores into the cytoplasm where the rRNAcombines with protein to form the small and large ribosomoal subunits Functional ribosome: involved in protein synthesis will be the small subunit + the large subunit Each subunit is made up of rRNAand protein Nucleoli are prominent in cells producing large amounts of protein Indicate 3 structures in the cell that will be in the abundance or prominent in the secretory cell: A) prominent rough ER B) high levels of bound ribosomes C) high levels of nucleoli DNAis double-helix; RNAis single stranded DNAisA-T G-C; RNAisA-U G-C DNAhas deoxyribose; RNAhas ribose Chromatin Composed of structural units called NUCLEOSOMES Each nucleosome consists of 8 histone proteins and threadlike DNAwrapped around the 8 histone proteins Function of the histone proteins in chromatin 1) packing the delicate threadlike DNAto prevent DNAfrom twisting or breaking 2) regulate the activities of the DNAwhen DNAis packaged with histone proteins the DNAis in its inactive coiled form called heterochromatin dissociation of the histone proteins from DNAresults in the DNAassuming its ACTIVE extended form called EUCHROMATIN DNAreplication Transcription DNA a type of nucleic acid 2 types of nucleic acids DNA RNA The structural unities for nucleic acids are NUCLEOTIDES Pentose sugar Nitrogen containing base Phosphate group Nitrogen containing bases in DNA A,G,C,T Nitrogen containing bases in RNAA,G,C,U Covalent bonds betweenA-T, G-C orA-U Cell Cycle 2 major sequential periods Interphase G1, S, G2 Cell Division Mitosis Cytokenisis Interphase st 1 major phase of the cell cycle composed of 3 sequential subphases G1—growth Cell is active in producing proteins Replication of the centrioles (in the centrosome) begin toward the end of the G1 phase Longest phase in interphase S—growth and DNAsynthesis Main event DNAreplication Ends with 2 identical copies of the DNA each will be passed on to each of the daughter cells formed after cytokinesis DNAreplication Enzyme: HELICASE untwists and unwinds the double helical DNAinto 2 polynucleotide chains that act as templates for the synthesis of 2 complementary polynucleotide chains The area of the separation on the double helical DNA REPLICATION BUBBLE The Y-shaped end of the replication bubble REPLICATION FORK st 1 DNAtemplate--- complementary polynucleotide chain 2 DNAtemplate--- complementary polynucleotide chain at the end of DNAreplication you will have 2 identical DNA each DNAis composed of the template (old polynucleotide chain) and a complementary polynucleotide chain (newly synthesized) DNAreplication is referred to as SEMI-CONSERVATIVE REPLICATION G2 Synthesis of proteins that include proteins that initiate/ maintain cell division Such as cyclin, cyclin-dependent kinase (cdK) and M-phase promoting factor (MPF) “GO PROTEINS” They give the cell the go ahead to enter into mitosis Replication of centrioles is completed Cell grows by increase in size due to protein synthesis that occurs during all the subphases of interphase Mitosis: 4 phases Compare and contrast prophase/telophase Hyperplasia: growth by increase in cell number=mitsosis Hypertrophy: growth by increase in cell size Cytokinesis: cytoplasmic division Cancer Cells Neoplasm: excessive proliferation of cells considered abnormal Benign- grows slowly and its confined to one location Malignant-CANCER- grows fast and aggressively; metastasizes into other organs 1 prevent DNAreplication b/c without replication (S phase) there will be no reproduction Inhibit the actions/production of the “GO PROTEINS” SUMMARY: Interphase EUCHROMATIN Protein synthesis and DNAreplication:ACTIVE DNA Cell division MITOSIS Inactive form of DNA HETROCHROMATIN Further condensed into short bar-like structures called CHROMOSOME Prevent entanglement, twisting and breakage as they move inANAPHASE Protein Synthesis 2 sequential events, transcription and translation Transcription (in nucleus) Only use one strand of DNAas the template DNAis transcribed in pre-mRNAand the pre-mRNA is edited (introns removed, leaving exons) into mRNA The helicase untwists and separates the 2 DNApolynucleotide chains 1 chain becomes the template strand and the other becomes the coding strand The pre-mRNA (primary transcript) is synthesized from the template using the law of complimentary of base pairings The template presents GTCAGT then pre-mRNA is CAGUCA At the end of transcription you have the pre-mRNAwhich consists of introns and exons Introns do not specify amino acids; EXONS specify specific sequence After transcription the pre-mRNA is edited to give the mRNA (only exons; introns are spliced out) mRNAleaves nuclear pore Coding strand (DNApolynucleotide chain not used in transcription)  has the same base sequence as pre-mRNA, except a T in the coding strand is replaced by a U in the pre-mRNA Translation (in cytoplasm) Occurs in the cytoplasm and involves 3 types of RNA mRNA rRNA forms part of the ribosome tRNA transfer RNA; 3 base sequence attached at 1 end and an amino acid at the other end 3 base sequences in mRNAis referred to as codon 3 base sequences in the tRNA anti-codon Triplet = 3 base sequence in DNA is the same as the anti-codon except t in the triplet is replaced by u What is the significance of the redundancy in the genetic code? It avoids problems that occur from mutations rd Base changes at the 3 base has little impact on the protein but if it is the first base then it can code for an entirely different amino acid 20 naturally occurring amino acids but 60 codons which takes care of minor mistakes that can occur during transcription but will not affect the type of amino acid specified EXAM 2: BONES AND JOINTS 11/20/2013 SKELETAL SYSTEM Cartilage 1. Hyaline 2. Elastic 3. Fibrocartilage Bones: each bone is an organ consists of bone tissue, connective tissue coverings, blood vessels and nerves 4 classes Long: Longer than they are wide Composed of diaphysis (shaft) and 2 epiphyses (extended ends of long bone) Most are located in appendicular skeleton Short: Roughly cuboidal in shape Located in the wrist= carpals and ankle= tarsal Special types of short bones called the sesamoid bones are embedded in tendons where they direct the pull of the tendon when the skeletal muscle moves Flat Flattened bones such as the sternum Tend to have a protective function= protect internal organs Cranial bones are flat bones protect the brain Irregular Not classified as long, short or flat vertebrae 2 types of bone tissue Compact: Located on the exterior part of the bone EXAM 2: BONES AND JOINTS 11/20/2013 Matrix is solid Appears dense and are composed of structural unites called OSTEONS Each consists of concentric rings of structures called LAMELLAE , hence compact bone tissue is also referred to as lamellar bone tissue In the core of the osteon is the Haversian canal contains blood vessels and nerves At the junctions of adjacent lamallea lacunae= house osteoctyes Osteocytes are kept viable by nutrients delivered from blood in the blood vessels in the Haversian canal by smaller air-like canals called CANALICULI Osteocytes are kept viable because they can revert to osteoblasts to secrete new bone tissue for repair and growth of the bone Spongy Located inside the bone covered externally by compact bone Structural units of spongy bone tissue needle-like structures called TRABECULATE Irregularly arranged creating large spaces to accommodate blood vessels and red bone marrow (also known as myeloid tissue source of blood cells and platelets and contains hemotopoietic stem cells) 2 regions of Long bone Diaphysis shaft of the long bone composed of a collar of compact bone surrounding the medullary cavity Contains red bone marrow (children) and yellow bone marrow (adults) Red bone marrow in the medullary cavity of long bones produces blood cells and platelets in children Yellow bone marrow in the medullary cavity of long bones of adults does NOT produce blood cells and platelets At the junctions of the diaphysis with the epiphyses: Epiphyseal plate : present in the long bone of children Epiphyseal lines: present in the long bone of adults 2 Epiphyses composed of spongy bone tissue with red bone marrow externally each epiphyses is covered by a thin layer of compact bone the ends of the epiphyses of long bones are capped by theARTICULAR CARTILAGE thin layer of hyaline cartilage EXAM 2: BONES AND JOINTS 11/20/2013 Membrane=2 types of CT membranes (long bones) Periosteum- the outer CT membrane that surrounds bones Double layered outer fibrous layer and the inner osteogenic layer Inner osteogenic layer contains osteoblasts and osteoclasts Osteoblasts: bone-forming cells – secrete bone tissue; derived from mesenchyme Osteoclasts: bone resorbing cells—destroy bone tissue Outer Fibrous layer of the periosteum  composed of the highly vascularized dense irregular CT Contains blood vessels, nerves and lymphatic vessels  these structures enter through the nutrient foramina into canals  right angles to the Haversian canals These right angled canals are called perforating or Volkmann’s canals Nutrients are delivered from blood inside the blood vessels in the fibrous layer and will go through the perforated canals to the blood vessels in the Havasian canals (central canals) to provide nutrients via canalicular to the osteocytes in the lacunae The perforating canals extend into the spaces within the spongy bone Spongy bone tissue stores red bone marrow in both children and adults Red Bone marrow = myeloid tissue  a source of the blood cells via a process known as hematopoiesis Attached to compact bone by tough collagenous fibers called Sharpey’s fibers Endosteum single layer, contains osteoblasts and osteoclasts Covers the canals, cavitites, and the trabeculae in a bone General structure of Flat, short and irregular bones 2 thin plates of periosteal-covered compact bone with spongy bone with the traberculae covered by the endosteum in between the 2 plates Ossification Prenatal Ossification = Osteogenisis (development of the bony skeleton form the embryonic skeleton) Intramembranous Ossification Begins after the 8 week of in utero life EXAM 2: BONES AND JOINTS 11/20/2013 Mesenchyme secrete fibrous connective tissue membrane  under goes intremambranous ossification to form membrane bones All membrane bones have flat are flat bones The 8 cranial bones and the 2 clavicles All membrane bones are flat bones but not all flat bones are membrane bones Endochondrial Ossification Mesenchyme produces chondroblasts Chondroblasts secrete hyaline cartilage  form the rest of the embryonic skeleton not formed by fibrous connective tissue membrane Ossification of the hyaline cartilage to form the rest of the bones in the bony skeleton All bones in the bony skeleton except the 8 cranial bones and the 2 clavicles Endochondrial ossification results in long bones, flat bones, short bones, and irregular bones After endochondrial ossification in long bones, hyaline cartilage still persists in 2 areas as the epiphyseal plates (at the junctions of the diaphysis with the epiphysis) and at the articular cartilage (caps the ends of the epiphysis) In short, flat and irregular bones you have complete ossification of the hyaline cartilage into bone Postnatal ossification-after birth Longitudinal Ossification  linear bone growth/ interstitial increases the length of bones = height Increase in length of the long bones due to activites in the epiphyseal plates at the junctions of the diaphysis and the epiphyses of a long bone Active zones in the epiphyseal plate  looking at the proximal epiphyseal plates 1. Growth/ proliferation zone Chondroblasts secrete new hyaline cartilage to add on to the epiphyseal face of the epiphyseal plate Growth zone is proliferation of chondroblasts = hyperplasia which results in the increase in hyaline cartilage secreted onto the epiphysial face of the epiphisial plate 2. Hypertrophic Zone The mature chondroblasts (chondrocytes) grow by hypertrophy (increase in size) Large chondrocytes require more nutrients to remain viable 3. Calcification (deterioration) zone  calcium phosphate crytstals (hydroxyapatites) are deposited in the matrix of hyaline cartilage  calcification of the matrix = solid matrix which will cause the chondrocytes to die 4. Ossification (osteogenic) zone osteoblasts move into the calcified matrix and secrete osteoid organic matrix of bone tissue EXAM 2: BONES AND JOINTS 11/20/2013 new bone tissue is added on onto the diaphyseal face of the ephiphyseal plate 5. Resorption zone osteoclasts reabsorb part of the newly added bone to increase the height of the medullary cavity as the bone lengthens In children, the amount (width) of the hyaline cartilage added on to the epiphyseal face=EQUAL to the amount (width) of new bone tissue added on to the diaphyseal face of the plate WIDTH (thickness) of the plates remain the same However, the proximal epiphyseal plates have shifted superiorly The distal epiphyseal plates have shifted inferiorly Results in the lengthening of long bones Hormonal Control of Postnatal Longitudinal Bone Growth (long bones) Growth hormone: stimulates hepatocytes to produce insulin-like growth factors (IGFs) Protein hormone that binds to growth hormone receptors on hepatocytes (liver cells) to stimulate the production of insulin-like growth factors (IGFs) IGFs bind to IGF receptors on the chondroblasts to stimulate chondroblast proliferation growth zone Hence, the growth promoting effect on growth hormone is INDIRECT in longitudinal bone growth Sex steroid hormones (testosterone in the male and estrogens in the female) synergize with growth hormone to cause “growth spurt” Synergize with growth hormone to increase IGF production by the hepatocytes Increase IGF= increase chondroblast proliferation= increase hyaline cartilage secreted on the epiphyseal face of the epiphyseal plates Equal thickness of ossified tissue on the diaphyseal face Hence, increase length of the diaphysis= increase bone lengthening After synergizing with growth hormone to stimulate longitudinal bone growth, sex steroid hormones begin to antagonize growth hormone from stimulating the hepatocytes to produce IGFs Decrease in IGFs= decrease in chondroblast proliferation= decrease in hyaline cartilage secreted onto the epiphyseal face However, the rate of ossification at the diaphyseal face continues and it eventually outpaces the rate of hyaline cartilage secretion the epiphyseal plates become ossified leaving a line called the EPIPHYSEAL LINE present in the long bone of ADULTS The ossification of the entire epiphyseal plates is termed epiphyseal plate closure Example of endochondral ossification occurring after birth (postnatal) EXAM 2: BONES AND JOINTS 11/20/2013 Towards the end of adolescence. The sex steroid hormones antagonize the actions of growth hormone and epiphyseal plates become ossified EPIPHYSEAL PLATE CLOSUREheight determined Appositional Bone Growth 2 type of postnatal ossification All bones widen and increase in diameter/thickness Bone formation on the external surface of the bone outpaces the bone resorption in the internal surface of the bone All bones in the body undergo appositional bone growth But only long bones undergo longitudinal bone growth Bone remodeling Adult bones constantly undergo bone formation on the periosteal surface and bone resorption on the endosteal surface bone remodeling Functions of bone remodeling: Maintain calcium homeostasis Allow for bone repair after fractures In healthy adults, bone density remains constant because Rate of bone formation= rate of bone resorption If the rate of resorption outpaces the rate of formation-= osteoporosis Control of bone remodeling Hormonal control How to maintain the normal calcium levels in blood In the human body 1200 g of calcium 1000 g stored in bones as the hydroxyapatites 200g left will maintain the blood calcium levels 9mg-11mg/100 cc of blood Blood calcium levels below 9 mg hypocalcemia Need to correct it by getting calcium stored in bone tissue EXAM 2: BONES AND JOINTS 11/20/2013 PARATHYROID HORMONE (PTH) is released to stimulate osteoclasts to cause bone resorption to release calcium from bones into blood PTH stimulate bone resorption (bone breakdown) to release the calcium phosphate salts in blood Stimulates the kidneys to excrete phosphate leaving Ca2+ in blood. Also stimulates calcium reabsorption from the kidneys- increase Ca2+ in blood PTH stimulates the synthesis of the most active form vitamin D called 1, 25 dihydroxyvitaminD Stimulates Ca2+ absorption from the small intestine SUMMARY: based on the actions of PTH increase in blood Ca2+ levels back into the normal range Blood calcium level above 11mg hypercalcemic You need to store excess calcium in bone tissue as the hydroxyapatites CALCITONIN is released to stimulate osteoblasts to produce bone tissue and release stimulate mineralization—uses calcium from blood Stimulates the osteoblasts to secrete NEW bone tissue The matrix of new bone tissue is mineralized by hydroxyapitites (calcium phosphate crystals): calcium levels in blood drop back into normal range Mechanical force/ stresses Wolff’s Law Bones remodel/grow in response to mechanical stresses placed on the bones Bones that are stressed-pulled often by contracting skeletal muscles undergo bone remodeling where bone formation outpaces bone resoprtion resulting in thickening of these “active” bones JOINTS=ARTICULATIONS Classification: 2 ways Functional: based on amount of movement allowed at the joint 3 types Synarthroses-immovable joints Amphiarthroses-slightly movable joints Diathroses- freely movable joints Structural: based on the material binding the body and the absence or the presence of a joint cavity 3 types EXAM 2: BONES AND JOINTS 11/20/2013 Fibrous joints: bones joined together by dense CT; joint cavity absent 3 types sutures- present only in the skull In children: sutures are amphiarthrotic joints In adults: sutures are synarthrotic joints gomphoses- short periodontic ligaments that connect the teeth into the alveolar sockets of the mandible and the maxillae hence, gomphoses are referred to as “ PEG-IN-SOCKETS” joints synarthrotic joints syndesmoses- ligaments or bands connect the bones fibrous material ligament membrane called interosseous membrane composed of ligaments synarthrotic joints composed of interosseous membrane amphiarthrotic joints interosseous membrane between the radius and the ulna allows for pronation of the forearm Cartilaginous joints synchondroses: joint formed by hyaline cartilage The epiphyseal plate connecting the epiphyses and the diaphyses of a long bone are synchondrotic joints which are synarthrotic joints symphyses: formed by fibrocartilage all symphyses are amphiarthrotic joints intervertebral discs between adjacent vertebrae pubic symphyses connect the os coxae (hip bones) the pubic symphyses is an amphiarthrotic joint that moves slightly to increase the pelvis inlet during labor Synovial joints: class of joints with a joint cavity present; hence, all synovial joints are DIARTHROTIC joints=movable Unique special features EXAM 2: BONES AND JOINTS 11/20/2013 1. The ends of the epiphyses of the long bones at the synovial joints are capped by the ARTICULAR CARTILAGE covers the ends of all bones forming synovial joints function: articular cartilage protects the surfaces of the bones as the synovial joints move to minimize wear and tear 2. Joint cavity: space that contains synovial fluid which acts like a lubricant to reduce friction 3. ARTICULAR CAPSULE: encloses the joint cavity double layered outer fibrous layer: composed of dense irregular CT inner synovial membrane: composed of areolar CT over dense irregular CT blood in the capillaries in the fibrous capsule is filtered and secreted by cells in the synovial membrane this filtrate is called the SYNOVIAL FLUID: located in the joint cavity and inside the articular cartilage function: synovial fluid acts as lubricant to reduce friction as the synovial joints move; synovial fluid provides nutrients to the chondrocytes in the articular cartilage; removes metabolic wastes from chondrocytes back into the blood of capillaries; synovial fluid contains phagocytes that engulf and digest cellular debris and any microbes in the joint cavity 4. Ligaments composed of dense regular CT that reinforce and stabilize synovial joints 3 types 1. Intracapsular ligaments: located deep to the articular capsule ex: cruciate ligaments of the knee joint 2. Capsular or intrinsic ligament: part of the fibrous capsule of the articular capsule that blends into the periosteum of the articulating bones ex: tibial collateral ligaments 3. Extracapsular ligaments: external to the articular capsule ex: popliteal ligaments Additional structures that may be present at certain synovial joints to add protection 1. Menisci certain types of synovial joints to improve the fit of the bones forming the synovial joint minimize wear and tear of the articulating surfaces ex: knee joint 2. Bursae= “bags of synovial fluid” that act as ball-bearings to decrease friction at sites of active synovial joints ex: shoulder joint, knee joint EXAM 2: BONES AND JOINTS 11/20/2013 3. Tendon sheaths elongated bursae wrapped around tendons subjected to friction; decrease friction; found around tendons rubbing against muscle, ligaments and bones 6 types of Synovial joints: based on the structure of the articulating surfaces of the bones forming the synovial joints the structure and shape articulating surfaces dictates the types of movements allowed Types of movements: 1. Gliding movements gliding or slipping of the articulating surfaces 2. Flexion movement which results in the decrease of the angle of a synovial joint the articulating surfaces get closer to each other 3. Extension movement that increases the angle of the synovial joint articulating surfaces separate pull away from each other bring a flexed knee to the anatomical position is an extension 4. Abduction movement of limbs away from the midline of the body 5. Adduction movement of limbs towards the midline of the body 6. Circumduction abduct the limbs and move the digits to describe a cone in space 7. Rotation movement around an axis 6 types 1. Plane joint : articulating surfaces are flat Movement allowed: gliding or slipping intercarpals and intertarsals 2. Hinge joint: one articular surface of one bone is cylindrical and the articular surface of the second bone is a trough; Hinge joints allow for flexion and extension Elbow joint 3. Pivot joint: the articulating surface of one bone is round and the articulating surface of the second bone is a sleeve or ring . Movement allowed: Rotation atlantoaxial joint allows for movement of the head to motion “NO” 4. Condyloid (Ellipsoid) joint: the articulating surface of one bone is an oval protrusion and the articulating of the second bone is an oval depression. Movements allowed: flexion, extension, abduction, circumduction, adduction atlanto-occipital joint allows us to motion “YES” 5. Saddle joint: the articulating surface of one bone has convex and concave surfaces articulating surface of the second has both concave and convex surfaces EXAM 2: BONES AND JOINTS 11/20/2013 Only one location in the human body carpometacarpal joint of the thumb 6. Ball-and-socket joint: the articulating surface of one bone is spherical and the articulating surface of the second bone is s a cuplike socket The ultimate diathrotic joint – freely moveable coxal joints and glenohumeral joints EXAM 2 NOTES: TISSUES AND SKIN 11/20/2013 Tissues 4 primary tissues: Epithelial, Connective, Muscular, Nervous Epithelial Characteristics: Polarity: lower/attached basal surface, upper/free apical layer Avascular: lack blood vessels Supported by a basement membrane: double layered Superior basal lamina abutting the epithelial tissue Deeper reticular lamina abutting the underlying connective tissue Connective tissue underlies/support it Vascular and provides nutrients to the overlying a vascular epithelial by diffusing through the basement membrane High regenerative capacity Innervated Membranous v. Glandular Membranous= covering/lining Simple- composed of a single layer Simple Squamous: (flattened-like cells with a disc-shaped nucleus) Single layer of squamous cells Location: Respiratory membrane in the lungs Filtration membrane in the kidneys Lines structures in the circulatory system Cardiovascular and lymphatic Specifically referred to as the ENDOTHELIUM EXAM 2 NOTES: TISSUES AND SKIN 11/20/2013 Forms part of the serous membrane where it is specifically referred to as the MESOTHELIUM Function: As part of the mesothelium is secretes the serous fluid that acts as a lubricant to reduce friction as these structures in the ventral body cavity move Diffusion of gases in the lungs (respiratory membrane) Filtration in the kidneys (filtration membrane) As the endothelium it presents a slick, frictionless surface for the flow of fluids: blood and lymph in the lymphatic system Simple Cuboidal: (box-like with centrally spherical nucleus) Single layer of cube-shaped cells with a centrally placed nuclei Location: Proximal convoluted tubules (PCT) and in the distal convoluted tubules (DCT) in the kidneys Surface of the ovaries as the outer membrane surrounding ovaries where it is specifically referred to as the GERMINAL EPITHELIUM Function: Reabsorption and secretion Simple Columnar: (long columns; elongated nucleus towards the basal surface of the cell) Single layer of tall cells with a elongated nuclei placed closer to the basal surface 2 types Ciliated: in respiratory tract and uterine (fallopian tubes in the female reproductive tract) Function: PROPULSION: cilia beat to create current that moves substances undirectionally Respiratory tract: propulsion of mucus Uterine tubes: propulsion of ova (eggs) or zygotes Nonciliated: in the lining of most of the structures in the gastro intestinal tract Function: SECRETION of enzymes required for the chemical digestion of nutrients (food) in the GI tract Pseudostratified columnar Single layer of columnar cells of different heights with their nuclei also appearing at different heights giving the false impression of stratification EXAM 2 NOTES: TISSUES AND SKIN 11/20/2013 2 types: Ciliated: have cells endowed with GOBLET CELLS: secrete mucin that when interacts with water makes mucous Specifically referred to as the RESPIRATORY EPITHELIUM: most of the structures in the respiratory tract are lined with this Nonciliated: lines the sperm-carrying duct in the male reproductive system such as the epididymis and vas deferens Phagocytize sperm that are not ejected through the urethral orifice Stratified: composed of at least 2 layers of epithelial cells: named the epithelial cell type based on the apical surface of the epithelial Stratified squamous: several layer of epithelial cells with the cell type on the apical surface being flattened with disc-shaped centrally placed nuclei Keratinized: the cells on the apical surface are DEAD cells impregnated with a tough fibrous protein called keratin Location: epidermis of the skin Function: abrasive-resistant and can withstand wear and tear Epidermis acts as a physical barrier against pathogens Nonkeratinized: apical cells are not filled with keratin—cells are alive Location: forms the superior part of the mucous membrane which lines the tracts of the bodyopenings to the exterior. The exit and entry points of the tracts are lined with mucous membrane with the nonkeratinized stratified squamous epithelial forming part of it GI Tract: Entry point: oral cavity Exit point: anal cavity Both cavities are lined with mucous membrane composed of nonkeratinized stratified squamous epithelial over connective tissue Stomach: lining is mucous membrane composed of simple columnar epithelium over connective tissue Functions: abrasive-resistant Stratified cuboidal and columnar Main function: protection Rare in human body Location: duct of multicellular exocrine glands such as sweat glands, salivary glands Function: stratification confers PROTECTION: interlay surface of ducts because the ducts carry secreted products from the glands, these epithelia are said to be involved in secretion EXAM 2 NOTES: TISSUES AND SKIN 11/20/2013 Transitional epithelium Location: lines structures in the urinary system that transport stored urine Ureters: slender-like tubes that extend from the kidneys to the bladder; transport urine from kidney to bladder Bladder: storage organ for urine Superior part of the urethra: drains urine from the bladder to the exterior Function: the transitional epithelia undergoes a “TRANSITION” from 6 layers with cubodial apical cells to 3 layers with flattened squamous-like cells as these structures fill with urine Undergoes a TRANSITION to increase the capacity of these structures to accommodate urine Glandular: epithelial cells form the secretory portion of the duct system of multicellular exocrine glands Endocrine: secretes their products directly into extracellular fluid Exocrine: secrete products onto body’s surface 2 types: Unicellular and Multicellular Unicellular – goblet cells (only unicellular) which are scattered within the membranous epithelial that secrete mucin (mucin +water=mucous) Multicellular: 2 types of classification Structural Classification Duct System (simple glands: unbranched duct; compound glands: branched ducts) Shape of the Secretory portion Functional Classification=mode of secretion Apocrine: apex of the secretory cell pinches off to release accumulated products (no example in human body) Merocrine: secretory cell undergoes exocytosis to release products Holocrine: secretory cells ruptures to release its accumulated products (ex: sebaceous glands) Connective tissue 1. All have a common origin: derived from embryonic tissue: MESENCHYME Exhibit a degree of vascularity Composed of 2 parts: nonliving and living portion EXAM 2 NOTES: TISSUES AND SKIN 11/20/2013 Nonliving: extracellular matrix= ground substance and fibers 3 fiber types collagen fibers: white fibers elastic fibers: yellow reticular fibers Ground substance Intestinal fluid Adhesion molecules Proteoglycans composed of glycosaminoglycens (GAGs) The more GAGs in the ground substance= the consistency of the matrix solid Living portion: cells that are derived from mesenchyme and they produce the connective tissue Fibroblasts: produce connective tissue proper (gel-like matrix) Chondroblasts: produce cartilage (semi-solid matrix) Osteoblasts: produce bone tissue (solid matrix) Hematopoietic stem cell: produce blood cells Connective tissue proper Living portion: secreted by FIBROBLASTS Consistency of the ground substance gel-like 2 subclasses (all of these will be secreted by fibroblasts) Loose Areolar: supports structures in the body hence, is also referred to as the PACKING MATERIAL of the body Location: Underlying epithelial tissue in mucous membrane where the areolar CT is given a proper name: LAMINAPROPRIA The papillary layer of the dermis (of the skin) is composed of areolar CT Highly vascularized EXAM 2 NOTES: TISSUES AND SKIN 11/20/2013 Function: 1. Support other tissue by providing nutrients 2. By virtue of the presence of the immune cells (macrophages, blood cells) in the areolar CT, its involved in the immune response 3. Excess interstitial fluid is held back inside areolar CT excess interstitial fluid in areolar CT is known as EDEMA Adipose: adipose cells= adipocytes, store triglycerides in the adipose CT Location: surrounds and supports all structures in the body Function: 1. For cushioning protects structures against trauma 2. Holds structures in their correct anatomical positions 3. Provides storage form of concentrated energy 1g of glucose= 4 kcal 1g of proteins= 4 kcal 1g of fat=9 kcal Reticular: Found in lymphoid organs (lymph nodes, thymus, spleen) that contain reticular CT that form a network inside these organs called the STROMA Lymphoid cells reside and proliferate in the stroma to provide immunity Dense: fibrous CT because of the fiber content Regular: bundles of collagen fibers arranged in an orderly, regular fashion (all fibers face in one direction)-->Can withstand stress applied in only one direction Location: Tendons: connect skeletal muscle to bones Ligaments: connect bones to joint sites Aponeuroses: sheet-like tendons that connect muscle to muscles over skeletal structures Poorly vascularized (tendons take a longer time to heal)—not taking enough nutrients in as fast as you can to repair Irregular: contains bundles of collagen fibers arranged in an irregular fashion (fibers face in all directions) withstand stress applied EXAM 2 NOTES: TISSUES AND SKIN 11/20/2013 Highly vascularized and provides nutrients to the structures it surrounds/supports Elastic: dense regular CT but with elastic fibers Function: exhibit the stretch-recoil properties Location: ligamenta flava which connect adjacent vertebrae Cartilage: secreted by chondroblasts; semi-solid matrix due to high levels of GAGs; a vascular; surrounded by PERICHONDRIUM (composed of dense irregular CT) that provides nutrients to the cartilage 3 types Hyaline: most abundant Embryonic, Epiphyseal,Articular and Costal cartilage Structure Appears glassy under light microscope Smooth appearance without obvious bundles of collagen fibers Shallow concavities called LACUNAE inside the semi-solid matrix matured chondroblasts called chondrocytes reside in the lacunae Location Most of the embryonic skeleton is composed of hyaline cartilage after ossification, some of the hyaline cartilage persists as 1) epiphyseal plates located at the junctions of the epiphysis and the diaphyses of the long bone Epiphyseal plates allow for longitudinal bone growth during childhood and adolescence. Toward the end of adolescence, the epiphyseal plates will close= EPIPHYSEAL PLATE CLOSURE Remnants of the epiphyseal plates are the EPIPHYSEAL LINES=present in the long bones of adults Consequence of the epiphyseal plate closure=height is determined 2) Articular cartilage thin layer of hyaline cartilage that caps the ends of epiphyses Articular cartilage acts as shock absorbers cushions the ends of the epiphyses to protect against wear-and-tear as bones move at joint sites 3) Costal cartilage connect ribs to the sternum costal cartilages act to anchor the ribs anteriorly Elastic: have more elastic fibers in matrix than hyaline cartilage Predominant fiber type=ELASTIC FIBERS appear as tangles in the matrix. EXAM 2 NOTES: TISSUES AND SKIN 11/20/2013 Location: 2 areas in the human body Epiglottis: covers the laryngeal opening during swallowing Pinna (external ear) directs sound waves into the external auditory canal Function: allows for these structures to be stretched under stress; and to recoil when the stress is released to assume their original shape/size “stretch-recoil” properties of elastic structures Fibrocartilage Predominant fiber type- collagen fibers Bundles of collagen fibers alternating with row of lacunae continued chondrocytes Location: Intervertebral discs located between 2 adjacent vertebrae in the vertebral column; act as shock- absorbers to protect the surfaces of the vertebrae together with elastic CT The fibrocartilage allows for the vertebral column to be flexiblebending Pubic symphysis “joins” the 2 hip bones (os coxae) hence, the pubic symphsis acts as a joint The fibrocartilage allows for the hip bones to be slightly stretched to increase the pelvic brim to allow for the passage of the fetus during parturition (“labor”)= flexibility Menisci pads Fibrocartilage inserted into synovial joints to improve the fit of the bones at the synovial joints decrease wear and tear Bone (osseous) Tissue: cell type secreted bone tissue= OSTEOBLASTS Consistency of the matrix= solid wit lacunae Mature osteoblasts called osteocytes reside in the lacunae Solid Matrix Organic matrix: osteoid Ground substance and fibers Predominant fiber type collagen fibers Ground substance increase GAGs Inorganic matrix EXAM 2 NOTES: TISSUES AND SKIN 11/20/2013 Composed of calcium phosphate crystals, which harden the matrix to make it solid Calcium phosphate crystals embedded in bone matrix hydroxyapatites Location: located in bones Function: basically the function of bones (the organs) Blood: fluid matrix plasma Location: blood vessels Transport respiratory gases and nutrients and wastes rd Nervous Tissue – 3 primary tissue Composed of 2 cell types Neurons: generate and transmit impulses (electrical signals) Supporting Cells: non conducting cells meaning they do not generate/transmit impulses 6 types Structure: 3 regions Cell body – contains the nucleus and acts as the biosynthetic region (for protein synthesis) Acentrosome (contains 2 centrioles at right angles) is absent hence, neurons are amitotic  not capable of undergoing mitosis Dendrite Axon Each neuron has only one axon and may have at least 1 dendrite  a neuron can have several dendrites Location: Nervous tissue forms most of the structure in the brain, spinal chord, and nerves Function: generate and transmit impulses to other neurons or to effector cells such as skeletal muscle fibers Muscle Tissue – 4 primary tissue type Organized with connective tissue, blood vessels, nerves to form organs called muscle Skeletal Muscle – each cell is referred to as a fiber because they are long and cylindrical Composed of long cylindrical cells  elongated cells are referred to as skeletal muscle fibers EXAM 2 NOTES: TISSUES AND SKIN 11/20/2013 Multinucleate—occurs when mitosis occurs without cytokinesis or from the fusing of several cells Length= 30 cm long When organized to form skeletal muscle it attaches to bone (both directly and indirectly) Combines with connective tissue, blood vessels, and nerves to form organ skeletal muscle Striated Structure: long, cylindrical, referred to as fiber Location: organized with blood vessels and nerves to form skeletal muscle structure Function: under voluntary control; for the voluntary contraction to cause body movement and facial expression  skeletal muscle is under VOLUNTARY CONTROL Cardiac Muscle Tissue Composed of cells that are highly branched and uninucleate BOTH SKELETALAND CARDIAC MUSCLE TISSUEAPPEAR STRIATED Function of the branching cardiac cells appear dark under the light microscope  these junctions are called intercalated discs Intercalated discs house 2 types of membrane junctions: Gap Junctions Desmosomes Location: organizes into cardiac muscle, the organ located only in the middle layer of the heart wall = the myocardium Function: cardiac muscle contracts under involuntary control to eject blood from the chambers in the heart Cells form gap junctions so they hold together, uninucleate Involuntary control Smooth Muscle: Composed of spindle shaped cells Uninucleate cells Organizes to form the organ called smooth muscle 2 types of smooth muscle organs EXAM 2 NOTES: TISSUES AND SKIN 11/20/2013 Single Unit: Function: cells located in the walls of hollow structures in the body’s tract contract under involuntary control to push substances down the tracts Multi-Unit: Function: contract under involuntary control to regulate the width or to regulate other structures Ex:Arrector Pilli Muscle in the Dermis In cold temperatures, the arrector Pilli muscles contract to decrease surface area available on the skin for heat loss Conserve heat in the body Central nuclei, no striations, arranged closely to form sheets Membranes as Simple Organs Organs have at least 2 types of tissues in it Simplest type of organs in the human body is the membranes Membranes are sheet like structures composed of at least 2 types of tissues Cutaneous Membrane = Skin Overlying tissue: keratinized stratified squamous epithelial tissue Underlying tissue:Alveolar CT (Papillary Layer) and then Dense Irregular CT (Reticular Layer) Mucus Membrane: lines structures in the tract of the body Overlying Tissue: At entrance and end of tract: non-keratinized stratified squamous epithelial Simple Columnar Epithelial for inner tract Underlying Tissue:Areolar CT referred to as the lamina propria Sereous Membrane Overlying Tissue: simple squamous epithelia = MEsothelium Underlying Tissue:Areolar CT Always epithelia supported by CT b/c epithelia needs nutrients from CT EXAM 2 NOTES: TISSUES AND SKIN 11/20/2013 Synovial Membrane – made up of 2 types of tissues but of the same primary class Integumentary System-2 divisions (skin and accessory skin structures) Skin is the largest organ of the body – surface area 1.2 to 2.2. square meters Weighs 9 to 11 pounds = 7% of the total body weight Composed of superficial epidermis and deeper dermis Varied thickness: 1.4 mm-4.0 mm Epidermis Based on thickness= 2 types of skin Thin skin= epidermis is composed of 4 strata 4 strata from deep-superficial stratum basale stratum spinosum stratum granulosum stratum corneum Thick skin= epidermis is composed of 5 strata Palms, internal surface of fingers, soles of the feet 5 strata from deep-superficial basale spinosum granulosum lucidum corneum all 4 layers are wider than in thin skin EXAM 2 NOTES: TISSUES AND SKIN 11/20/2013 additional layer of the stratum lucidum above the stratum granulosum and below the stratum corneum Stratum Basale deepest stratum of the epidermis abutting the basement membrane above the dermis Single layer of cuboidal cells called KERATINOCYTES (mitotically active always undergoing mitosis to produce cells that occupy more superficial strata) Because the keratinocytes are constantly undergoing mitosis, the stratum basale is also known as the STRATUM GERMINATIVUM Melanocytes produce melanin that is enclosed in melanosomes (arrange on the top/superficial sides of the keratinocytes in the stratum basale) Melanin acts as a chemical shield protecting the mitotically active keratinocytes from mutations that can occur by the UV radiation in sunlight Merkel cellscouple with the nerve endings in the papillary layer of the dermis to form MERKEL DISCS Merkel discs act as touch receptors for light touch Merkel cells do not act as a touch receptor only MERKEL DISCS Stratum Spinosum superficial to the stratum basale (immediately above the stratum basale) Composed of several layers of cells cells joined by desmosomes Cells contain intermediate filaments called TONOFILAMENTS DESMOSOMES and TONOFILAMENTS allow the stratum spinosum to withstand pulling forces without the cells separating Cells appear spiny Epidermal dendritic cells Langerhans’cells act as macrophages to engulf and digest pathogens and to activate the specific immune response if the pathogen gains access to the body Hence, intact epidermis is our first line of defense against pathogens Stratum Granulosum above the stratum spinosum 3-5 layers of flattened cells filled with granules 2 types of granules keratohyaline granules: conatin tough insoluble proteins called KERATIN that make the epidermis tough and abrasive-resistant lamellated granules: contain glycolipids that make epidermis water-proof Stratum Lucidum only present in thick skin; above the stratum granulosum 3-5 layers of DEAD cells layer of the stratum appear translucent under the light microscope EXAM 2 NOTES: TISSUES AND SKIN 11/20/2013 Stratum Corneum 20-30 layers of dead, flattened squamous-like cells, hence the epidermis consists of 4-5 layers of cells is a stratified squamous epithelium dead cells in the stratum corneum filled completely with keratin cells are keratinized and the epidermis becomes the keratinized stratified squamous epithelial dead cells are coated with glycolipids
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