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BIOL 2005
Ryan Chlebak

Human Physiology ­ BIOL 2005 ­  Midterm Notes: Gabriella Espost100853922 Lecture 1: The scientific method: ­ (hypothetical/deductive reasoning) ­ observations ­ hypothesis ­ experiments ­ analyze data Over 200 cell types in the body: 4 Major Groups: ­ neurons ­ muscle ­ epithelial ­ connective General Rule: Cells of a given type tend to cluster together = tissues. Neurons: Use electrical signals as information Muscle: composed of fiber cells, voluntary, unvoluntary movement Both skeletal muscle and smooth muscle Epithelial: Numerous cells make up this category. Sheet like, continuous layers. Found as surfaces and linings. *Able to separate fluids from environments Glands can be formed in E cells.  Exocrine vs. Endocrine (ducts vs. no ducts) Connective Tissue:  ­ blood, bone, fat, etc. ­ provide physical support for other cells types ­ tendons ­ legaments ­ bones ­ elastic tissue Extracellular Matrix: elastin, collagen, blood & lymph: connects various body parts, i.e.  blood, O2. Organs & Organ Systems: ­ Comprised of 2 or more tissue types ­ Perform particular functions (i.e. heart pumps blood) The body as an External Environment ­ kept external by epithelial tissue – skin lining of lungs, kidney tubules,  gastrointestinal tract. The body as an Internal Environment ­ Extracellular fluid – exchanges materials with blood ­ Blood is contained in vessels lined with endothelium, no connection with external  environment. Exchange points – lungs (O2 IN)(CO2 OUT) Gastrointestinal tractL Break down food, excrete salts etc. Kidneys: filtration, selective transport, excess waste products removed (water, inorganic  salts, nutrients etc) Body Water: ­ most abundant thing in the body (60%) ­ act as solvent, inorganic salts, ions, sugars, amino acids, proteins ­ Total Body Water (tbw) enclosed be outer epithelium. ICF and ECF. Homeostasis: ­cells in our bodies depend on each other, cells are sensitive to chance (must be regulated) Mechanisms: Keep conditions constant allows is to live in hot, cold, climates, elevation etc. HOWEVER ­ one organ system does not function to maintain homeostatic balance =  reporoductive system! Disruption of homeosatsis can lead to disease, sickness = heat stroke, heat exhaustion NEGATIVE FEEDBACK CONTROL SYSTEM ^^^^^^ POSITIVE FEEDBACK CONTROL SYSTEM   vvvvvvv ­ response to stimulus in the same direction, not indefinetly, will terminate  eventually. Much less common, e.g. sneezing, child birth Lecture 2 – Cells (Structure, function, metabolism) ­Chem review­ Water as a solvent is very important to cell function (water molecules = polar) Biomolecules: ­ molecules synthesized by living organisms ­ contain carbon atms (4 electrons valence shell) ­ 4 types: carbs, lipids, proteins, nucleotides Carbohydrates: ­ major source of E in the body ­ C:H:O = 1:2:1 ratio ­ Polar molecules ­ Hydroxyl groups (­OH) and hydrogen’s (H) ­ 3 sub categories: monosaccharide, disaccharides, and trisaccharides Condensation: (dehydration synthesis) ­ hydrolysis, water molecules splitting up, water must be present to react. Lipids: ­ nonpolar ­ C and H atoms, covalent bods ­ O is common too ­ Amphiphatic – contains polar and nonpolar regions 5 Classes of Lipids: 1. Triglycerals 2. Keytones 3. phospholipids 4. eicosanoids 5. steroids Proteins & Amino Acids ( P’s are polymers of AA’s) Amino Acids­ simple organic compund containing a carboxyl group –COOH and an  amino NH2. Polypeptides­ polymers of amino acids, peptide bonds join 2 amino acids. Protein Function: 4 levels: ­ Primary:  ­ Secondary: alpha helixes, beta pleated sheets, ­ Tertiary: much more complex pH disrupts this shape ­ Quatiary: hemoglobin, 4 polypeptide chains. Nucleotides & Nucleic Acids: ­ Function in energy transfer within cells ­ Form the genetic material of the cell ­ Nucleotide, 5 carbon carbohydrate, nitrogenous base, phosphate group DNA: Found in nucleus, two nucleotides coiled into double helix Bases: (A)(G)(C)(T)  = CG 3H bond……….AT 2H bond 3’ carbohydrate end 5’ phosphate end RNA: Found in cell nucleus and cell cytoplasm.  Cell Structure: Cells can be membranous or not. Plasma membrane seperates cell from external  environment. Phospholipid Bilayer: ­ basic structure of membrane ­ can move laterally, side to side ­ cholesteral can be found within bi­layer ­ barrier for large polar particles. Membrane Proteins: ­ Integral, embedded within lipid bilayer dissociated only by physically disrupting  bilayer. Amphiphatic = polar and non polar regions. ­ Peripheral, loosely bound to membrane, can be dissociated from membrane  without disruption, most are found on the cytoskeleton. Nucleus: main function transimission and expression of genetic material encoded in  DNA. Cytosol: gel­like fluid, molecular composition, critical to cell function Cell to Cell Adhesion: Tight Junctions – common in epithelial tissue specialized for molecular transport. Provides support so cells don’t tear apart under stress. Gap Junctions: membrane proteins (connexions) bins 2 adjascent cells. Cells in General: Function ­ metabolism and cellular transport ­ intercellular communication( release chemical messenger) Protein Synthesis: DNA contains “the code” for the creation of all proteins (only one strand = template  strand) Triplets, the sequence of 3 bases = codon. Regulation of Protein Synthesis: watch video* Protein degradation: Most proteins stick around for a long time,  Transcription: where rNA is synthesized using information from DNA. Plasma Membrane: • Membrane proteins: integral – found within the lipid bilayer, only dissociated by  physical disruption. • Peripheral Membrane Proteins: loosely bound to the membrane lipids or to  proteins, membrane carbohydrates: covalently bount to membrane lipids or  proteins. Organelles: Cell Division: Mitosis­ Interphase Prophase Prometaphase Metaphase Anaphase Telophase =======cytokinesis (cytoplasm divides, cleavage, final stage) Metabloic Reactions in the cell: • Catabolic: breaking down large molecules to small ones, i.e. proteins –amino  acids, glycogen – glucose molecules • Anabolic: larger molecules constructed from reactants i.e. amino acids – proteins,  etc. • Metabolic Pathway: When the products of one reaction serve as the reactants of  another i.e. A – B – C – D  Types of Reactions: Hydrolysis & Condensation Hydrolysis – water reacts with molecules breaking down the bonds that link the  molecules together Condensation: joining two smaller molecules together, generating a water product. Phosphorylation: Adding or removing a phosphate group Oxidation­ reaction that removes electrons from an atom or molecule Reduction – an atom of molecule gaining electrons Energy Transfers in reactions: Exergonic = proceed spontaneously in the forward direction Endergonic = go forward only when energy is put into the process, may spontaneously go  in reverse if no energy is put in. Reaction Rate Factors: • Concentration • Temperature • Activation energy heights – rate of reaction increases as barrier height decreses • Enzymes biomolecules that act as catalysts for chemical reactions • Specificity: enzymesa are able to recognize and bind to specific substrates, some  can bind to a range of substrates, some are very specific • Cofactors:Non protein components, allow enzymes to function • Coenzymes: no catalytic activity, attatch to enzymes Enzymes in reaction rates: FAD NAD CoA th September 19 , 2013 – BIOL 2005 Summary of Lecture #3 – Chapter 4, Cell Membrane Transport Last time we covered: • ‐ Chapter 2 and 3, cell structure and metabolism • ‐ The makeup of the cells, chemical reactions within the cell, enzymes, Introduction and brief announcements ‐ Guest lecturer, Dr. Jeff Dawson General Concepts of the Chapter • ‐ Transportation of material is also communication • ‐ Why do cells need to communicate between each other? Transport  the need to move cargo |  Communicate ‐ > within ‐> Between Chemical communication – Exported – Imported ‐> Detection – electrical gradients ‐ lipid signals Transport: 2 primary Mechanisms Passive Transport (Energy Independent) • ‐ Simple diffusion • ‐ Carrier mediated diffusion (facilitated diffusion) • ‐ Ion Channels Active Transport (Energy Dependent) • ‐ Primary • ‐ Secondary Passive • ‐ The energy needed is already present Driving forces on molecules • ‐ Kinetic Energy (Temp etc) • ‐ Charge • ‐ Concentration Diffusion – chemical, electro chemical Ions – Carry +ve or –ve charge, Chemicals – concentration matters Note: 99% of the dry weight in the body is water, overall very few chemical reactions going on in the body. ‐ Most important concept: Simply having the ions in the body is significant van’t Hoff Equation (Pg. 95. Toolbox) ‐ Chemical driving force for an uncharged solute to move into a cell Ion Size Cl small molecule, can diffuse faster, can cause an excess of –ve charge in one place under the right circumstances Na larger than Cl , slower moving. If the movement of Na+ is blocked within a system (membrane separating 2 areas) a charge difference can occur between the two areas (sides). ‐ ‐ Blocking the movement of Cl , Na+ will be drawn to the Cl concentration. Similar result. Nernst equation – Calculating the magnitude of the driving force (Pg. 99, Toolbox) Ex. NaCl inside and outside the cell • ‐ Driving force for Na+ to go into the cell • ‐ Electrical difference is generated because of the difference • ‐ Allows Na+ to be a “messenger”, fast acting. Rapid electrical communication (chemical is much slower) ‐ Facilitates evolution to a ‘faster’ lifestyle, higher organisms Na K pump  slow mechanism of transport  keeps electronic gradient across the membrane intact Fick’s law and Equation (Pg. 103, Toolbox) ‐ accounting for net flux and size of concentration gradient Flux = amount of material crossing a membrane of unit area/unit time. Movement from one side to the other – probabilities dictate how much Increasing surface area – maximizes the concentration gradient e.x . Fish gills, human lungs Membrane bound structures • ‐ fat soluble molecules can easily diffuse into cells through membrane bound structures • ‐ Water can partially move past the membrane as it moves about 10 Minute Break Facilitated Diffusion Membrane proteins themselves are affected by the lipids in the membrane. • ‐ Carrier mediated diffusion (Glucose is one example) • ‐ Glucose binds to a binding site • ‐ Conformational change occurs • ‐ Glucose moves from outside the cell to inside • ‐ Glucose is released (substrate attraction, concentration or affinity change may cause this) • ‐ Glucose binding de‐stabilizes the protein to allow the conformational change to occur. Co‐transporters + Na ‐‐ Galactose, transporter GLUT 4 – (Pg. 106, Focus on Diabetes box) ‐Transport membrane protein ‐ Not enough insulin, GLUT 4 is not expressed, glucose remains in the blood stream 3D structure, top and side view slide Fig. 4.10 • ‐ If glucose concentration and flux rate is low • ‐ Proteins become ‘busy’ concentration increases until leveling off, saturation has occurred at this point. • ‐ Rate of diffusion is maximized. Approx 10,000/second – glucose molecules, membrane transport into the cell Others – Pores in the membrane Aquaporins – 13 classes, discovered in 1992. • ‐ Only transport water molecules • ‐ Different roles for water in different tissues, thus different demand Figure showing water molecules passing through the Aquaporin • ‐ Protein structure has charged amino acids, matches water molecule charges. • ‐ Journal article – showing the ‘space filling’ figure of the molecules. • ‐ This channel type does not bind anything to it. Ion Channels • ‐ Pores do not bind • ‐ Channels can bind • ‐ Figure 4.12. Slide from BIOL 3305 – a) Na+ channel pore b) K+ channel pore + ‐ Water binds to ions, Na + H2O, can still fit through the channel ‐ Larger molecules do not fit To allow ions to pass through water must be stripped off. K +H2O – K+ proteins remove water ‐ Conformational changes Pore size selects for correct ions Selectivity filter – allows specific ion+water to be processed Some ion channels only open when certain conditions inside the cell are met. e.g. voltage gated channels – nerve and muscle function Primary Active Transport Na+/K+ ATPase – best example of this Figure 4.14. • ‐ Only Na+ inside to outside, K+ form outside to inside • ‐ ATP‐ covalent reaction, phosphate binds and protein structure flips, Na+ released • ‐ Phosphate releases after K+ binds, K+ inside the cell Primary • ‐ Molecule doing the direct movement Secondary • ‐ Piggy backs onto primary, moves molecules from low to high concentration Figure showing Lumen and model of water re‐absorption (Kidney) ‐ Transport processes can couple, just like reactions Renal functions ‐ Glomerulus + nephron, blood circulates, waste accumulates Only some ions are ‘recognized’ by the body. Certain ions and molecules Adaptive reasons for this‐ why? Kidney increases surface area + + ‐ Pumps pull Na out of the cells, Na can then flow back in from the lumen, + recovering Na from the waste product of the body ‐ Na+ can also be co‐transported into the cell. With: Glucose, Cl , Vitamins, + + When Na is constantly pumped out, K keeps being pumped in ‐ Leaky K+ channels allow it to leak out again ‐ Cycle continues + + K is not co‐transported – unknown why selection for K did not occur. Osmosis ‐ Diffusion ‐ Flow of water across a membrane down its concentration gradient Sugar can draw water out of fruit (strawberry example). Figure 4.20 ‐ Osmolarity #s and changes 1° ‐ glucose 0.1 mol/l = 0.1 osmol 2° ‐ NaCl o.1 mol/l = 0.2 osmol Water amount is inversely proportional to ions Pressure can counter diffusion from osmotic pressure Increase pressure of a system will decrease diffusion potential Reverse Osmosis systems work this way – pure water out Tonicity ‐ solutions Hypotonic – causes cells to swell Hypertonic – cells shrink Remaining Ch 4 material – will briefly be covered in Lecture #4 ‐ Endocytosis ‐ Exocytosis ‐ Movement of molecules across 2 membranes ‐ Trancystosis Readings for this Lecture ‐ All of Chapter 4 is relevant, please read. Lecture 4: Sept. 26 th Endocytosis: Phagocytosis: Cell “eating” the plasma membrane engulfs a particle, which is then  broken down by lysosomes. Pinocytosis: Cell “drinking” the plasma membrane engulfs small particle solutes and  filters them in. Receptor Mediated Endocytosis: endosomes carry material into the cell with them. Carrying Material Out of the cell: Exocytosis A vesicle from inside the cell fuses with the plasma membrane and realeases particles on  the out side.  (3 functions too = adds compartments to the membrane, recycles receptors,  and excretes substances to the extracellular fluid). Epithelial Tissue is the barrier between internal and external environments. ­ Absorption = into the cell ­ Secretion = out of the cell   Movement across 2 Membranes: ­ solute transport = Na+ K + pump ­ water transport = osmosis ­ transcytosis = endocytosis and exocytosis Clinical Example: Cystic Fibrosis: affects the respiratory tract, thick mucus build up affects breathing  ability. Normally watery fluid is able to dilute the mucus. Water osmosis follows solute transport. – problem with Cl­ transport, i.e. water transport  has no path to travel to dilute mucus. Chapter 5 – Chemical Messengers: 3 Categories of Chemical messengers: Paracrines: secretions released from/to adjascent endocrine cells. Neurotransmitters: chemicals (neurotrines) released into interstitual fluid by neurons  (synaptic signaling) Hormones: released from endocrine glands into interstitual fluid, travel via blood flow. Chemical Messengers to know: ­ Acetylcholine: a neurotransmitter that triggers the control of skeletal muscle  contractile activity.  ­ Amino Acids 4 acting as nuerotransmitters, synthesized within the neuron  that will secrete them (glutamate, aspartate, glycine, gamma­aminobutyric  acid(GABA)) ­ AminesDerived from amino acids, synthesized in the secretory cell except  thyroid hormones ­ Peptides & Proteins: cytosolic mRNA is template, codes for amino acid  sequence ­ Steroids: cholesterol processed in series of reactions, in smooth ER or  mitochondria ­ Eicosanoids: similar to steroids (immediate release) Enzyme catalyzes release  of arachidonic acid from membrane phospholipids Transport: ­diffusion ­dissolved blood (must be hydrophilic)ccccccccfffcfccdrt5 ­bound to carrier proteins in the blood Chemical Messengers need to bind to target cells in the nucleus. Target Sites: ­ Intracellular: lipophillic (cytosol or nucleus of target cell), alters protein synthesis ­ Membrane bound, lipophobic: 3 categories: ­ Channel linked: fast and slow, ion movement ­ Enzyme­linked: act as enzyme and receptor ­ G­protein­linked: activated G­proteins in PM, g proteins act on effectors (ion  channels and enzymes) Signal Amplification and Long Distance: SA: relies on second messengers to produce a greater response from target cells when  only a small concentration are present. Long­distance: endocrine and nervous system perform these tasks Protein synthesis: The Endocrine System: ­ Primary organs: function to secrete hormones is first function, some in the  brain, most outside the nervous system: Hypothalamus and pituitary gland =  together regulate almost all body systems. Pituitary gland= anterior and  posterior. E.g. Antidiuretic Hornome (ADH) when concentraion in plasma solute is  high, target cells in the kidneys pick up on this and the hypothalamus  synthesizes neurons to increase water absorption (treat dehydration). More  e.g.s adreanal glands and pancreas. ­ Secondary organs: secretion of hormone is secondary to other functions, many  organs form other systems too. i.e.  Primary Organs: Pineal gland, thymus, thyroid, parathyroid, adrenal glands, pancreas Adrenal Gland: Gonads, testicles and ovaries: Secrete various hormones, testosterone, progesterone, etc Secondary Organs: Heart, liver, kidneys, skin….all help to maintain the body, heal, growth. Secretion of Hormones: Hyposecretion: too little hormone secreted (think diabetes, not enough insulin) Hypersectretion: too much hormone secreted E.g. Acromegaly – hormone released to age too quickly….think picture of the lady at  52!! Whole Body Metabolism: We eat food for energy. Endocrine system controls whether we use or store that. Food intake is intermittent, food  is stored and then broken down between meals. Glucose levels must be maintained at all times to ensure brain function. Body temperature regulation = hypothalamus regulated. Growth Regulation  = Growth hormone (GH) Factors that affect GH: ­ diet ­ sleep ­ exercise ­ age ­ stress ­ anterior pituitary secretion of (growth releasing hormone, growth inhibiting  hormone)t2 ­ Bone Growth: GH increase bone strength, circumference and length. Osteoblasts: lay down new tissue on outer bone surface. Osteoclasts: reabsorption of bone at inner surface. Chronodcytes: Produce cartiladge, elongate bone, usually stops after adolescence. Thyroid Hormones: ­ enzymes & iodide are required to synthesize TH (thyroid hormone) ­ Primary action = raises bodies basal metabolic rate Glucocortoids, maintain concentration of enzymes able to break down  proteins, fats and glycogen Cortisol = the hormone for stress, helps the body adapt, blood flow to brain Human physiology ­ October 3rd 2013 Nerve Cells, Signaling, Synaptic Transmission, and Integration (Chapter 7 & 8) CNS & PNS Central Nervous System: • Composed of Brain and Spinal Cord Processing of signals from the PNS. (all input information is processed here) And then  sent out to certain organs. As well, it is the site of learning, memory, emotions, thoughts,  language, and complex functioning Peripheral Nervous System: • Afferent (Receive): Somatic, special, visceral (process info from organs and send  to CNS) • Efferent (Send): somatic & parasympathetic (transmit info from CNS to effector  organs) Somatic: volunrary (skeletal muscle contraction) Autonomic: involuntary (sweat glands, blood vessels) Further divided into:  parasympathetic, sympathetic) Enteric Nervous System – neurons in gastrointestinal tract, independent function but  communicated with autonomic.  The Nervous System: Cells Neurons: smallest functional unit of the nervous system (composed of cell body,  dendrites, axon) *As adults we have all the neurons well ever get. Stem cells – present in the brain, can differentiate into neurons (Can replace Neurons!! Dendrites – branches, receive input from other neurons at synapses Synapses – branch patterns vary per neuron type. Axon – nerve fiber, sends info, 1mm ­1m in length – can be branched, variable per cell  type Presynaptic neuron – one sending the signal Postsynaptic neuron – receiving the signal Signal Transport: Anterograde – moving from cell body to axon terminal Retrograde – moving from axon terminal to cell body Specialized Functions of Neurons: ­ability to alter ion permeability on the PM (to alter electrical properties) Leak Channels – nongated, always open create resting membrane potential Ligand­gated Channel – open or close in response to chemical binding to a receptor in the  PM Voltage­gated channels – open or close in response to change in membrane potential. Mechanically –gated channel Structural Differences in Neurons: (3 main types) Bipolar – cell body is in the middle of the neuron with dendrites on both sides Pseudo­unipolar – one axon with one peripheral and one central dendrite Multipolar – multiple projections from the cell body (1 axon +dendrites) CNS organization: cell bodies group and form nuclei, axons and dendrites grouped as  well, bundles PNS organization: cell bodies group to form ganglia (outside of the central nervous  system) axons bundle to form nerves Internuerons – in CNS, 99% of all neurons in the body involved in all processe of the  CNS. Glial Cells Glial “glue” cells – 90% of the cells in the nervous system (support for neurons, by  supporting structure and metabolically) 4 Types of Glial Cells: astrocytes, microglia, oligodendrocytes, Schwann cells Myelin – insulating layer from oligodendrrocytes (many cells coated)  and Schwann cells  (only one cell coated). Nodes of Ranvier – gaps within myelin Axonal membrane contains VG­Na+ and K+ channels ­transmission of AP by allowing ion movement across the membrane REVIEW: Ohm’s Law =    I = E/R KNOW THE TERMS, MULTIPLE CHOICE Q’s******** Table 7.1!!!!! (action potential, equilibrium potential, etc) The Nervous System – Membrane Potential Resting Membrane Potential (RMP) ­ in neurons, around ­70mV ­  more negative inside than outside the cell Na+ is higher concentration outside the cell (balanced by Cl­ outside the cell) K+ is higher concentration inside the cells(A­, primarily proteins) Neurons are permeable to both Na and K There are more open K+ channels than Na+ (approx 25x) Ions travel in the direction of driving force Due to permeability differnce, net outward movement of +ve charge results ina negative  membrane potential  When ion flow = all equal, no net movement of positive charges move in or out of  neuron. (=­70mV) Resting = 70mV Na+ =+60mV K+= ­94mV Gated channels, alter membrane permeability when they open or close, affect ion  movement across the membrane (voltage­gated, ligand­gated, and mechanically gated) Graded potentials – small electrical signals, in a short range, occur when the ion  channels within the membrane are open(aka stimulated) Magnitude of Stimulus is in  relativity to the strength of the graded potential. They degrade overtime,  dissipates. Action potentials occur when graded potential is depolarized juuuuuuuust enough to  reach threshold. Excitatoy­ membrane potential change towards the threshold Inhibitoy­ membrane potntial change away from the threshold Summation­ important for AP initiation (can build off eachother and add up to reach  threshold) Action Potentials:             AP will propogate over a long distance (axon) without losing their strength (add up),  makes then very good communication signals! (good travellers) In the neuron, 3 phases: ­ rapid depolarization ­ repolarization ­ after ­ hyperpolarization Ion Channels –voltage Gated (Na+ & K+) Primarily found in PM of axon hillock and axon ­ myelinated: concentrated more in the nodes of ranvier ­ unmyelinated: evenly distributed along the axon 2 Types of Gates:  ­ activation ­ inactivation Closed and capable of opening: inactivation gate =open, activation gate =closed,  depolarizing stimulus can open Open, both gates open, Na moves through, depolarization phase. Na+ gate opening is a positive feedback system, Na channels open, Na moves through,  triggering more Na channels to open etc. AP threshold level is the same one required to initiate the regenerative opening of the  channels K+ voltage­gated channels: ­ single gate, slower response ­ Positive charge movemnt out o f the cell repolarizes it ­ Part of negative feedback loop All or None Principle: AP’s commence once threshold is achieved, no aprtialAps occur , the amplitude of the AP  is the same (not graded). Action potential will therefore always act to its fullest.(always the same) Refactory Period: (neurology) the time after a neuron fires or a muscle fiber contracts  during which a stimulus will not evoke a response.)(approx 5­15ms) The time frame of reduced excitability divided into 2 phases: absolute and relative  refractory periods. Propogation: Ap’s propogation down the axon to the axon terminal without decrement. Electronic conduction allows current to dlow to adjascent areas from the stimulus area.  (resting – propogation) Length Constant: Distance where initial change in voltage has decayed to (37%) of its value. A measure of  how far the axon current can flow before leaking out of the axon. Depends on resistance to current flow. The greater the membrane resistance Diameter affects axial resistance. Myelinated (from Glial cell) Axons: an insulation support functioning to cover and  protect the axon. Lecture 6 – CNS and Sensory Systems  Glial Cells Cont’d: We covered 2/4 Glial Cells in last chapter (Schwann, and Ocygloceryotes) Now… Astrocytes: ­ star like formation ­ Form tight junctions between endothelial cells ­ Patch and cover axons (can cover many) ­ Protect neurons from toxic substances etc. Microglia: ­ active immune defence! ­ Protect the CNS via phagacytocis ­ Patrol the brain! J Blood­Brain barrier, makes it difficult for infections to easily reach vulnerable parts of  the brain, seperates the brain blood flow from other parts of the body (tight junctions) Physical Support: Meninges: 3 tissue layers Cerebrospinal fluid: shock absorption Dura Mator: Closest to the bone, outermost, tough Archanoid Mator: middle layer, weblike appearance Pia Mator: innermost layer adjascent to nerve tissue The CNS Blood Supply: 15% blood pumped from heart goes to CNS 20% of all consumed oxygen is by the brain 50% of all consumed glucose goes to the brain Matter Make­up of the CNS: Grey Matter & White Matter: Spinal Cord Matter Make­up: White matter on the outside, grey matter on the inside. Spinal Cord makeup: ­ Cervical(8) ­ Thoracic(12) ­ Lumbar(5) ­ Sacral(5) ­ *coccygeal nerve (1) Grey Matter = dendrites, cell body White Matter = Axons/ myelination Spinal Column: Dorsal Horn: dorsal side horns Ventral Horn: ventral side horns Lateral Horn: in between dorsal and ventral White matter has ascending and descending tracts that communicate between various  levels of spinal cord and the brain. The BRAIN: 3 major parts: brainstem, cerebellum, Forebrain: Forebrain:  ­ cerebrum ­ diencephalon(thalamus, hypothalamus, pituitary gland (tiny), pons, medulla  oblongata) Cerebellum Brainstem: spinal cord Parietal Lobe: sensory, touch, temp, itch, pain Frontal Lobe: Motor cortex = language, personality, choices Ocipital Love: Process visual information Temperal Lobe: Hearing Functions Language: 2 area’s: Broca’s area: express language, ie. Speak Wernicke’s area: ability to understand language Learning & Memory: 2 different of Learning types: ­ Associative: connections between 2 or more stimuli made ­ Nonassociative: the repetition of a single stimuli Memory 2 types: ­ Procedural: skills and experiences ie. How to ride a bike ­ Declarative: facts and knowledge Sensory Systems: ­ VISION:  3 layers of photoreceptors in the eyes: inner layer(ganglion cells), middle layer( modulators), outer layer(rode &  cones) Sensory Systems: HEARING: Sensory Systems: TASTE: Chemoreceptors in the mouth respond to the chemicals in food. Signal transduction: sweet, sour, bitter, salty… Proteins on the receptor cells on the tongue signal the release of Ca+, engage gate  activated channels Olfaction: the organ responsible for smell, located at the base of the nasal cavity. Lecture 7 – The Autonomic & Somatic Nervous System/ Review Lecture October, 17  2013 Chapter 11 – Efferent Nervous system:  2 Branches: • Autonomic NS: innervations of most effector organs and tissues (broad) Functions occur at subconscious level Also known as the “involuntary” nervous system Primary Function: maintain homeostasis, maintain the bodies operations. Maintain the balance inside the body. Dual Innervation: 2 more branches within the autonomic nervous system are: Sympathetic and parasympathetic systems, both innervate most organs, effects are  diametrically opposed to each other. ­Parasympathetic: “rest & digest” resting conditions, simulating digestive organs, inhibiting cardiovascular system. ­Sympathetic: “:fight or flight” Excitation, active periods, heart rate, force increase, blood flow shift and energy  stores mobilized. Two Types of neurons arranged in these series: Preganglionic neurons – from CNS to autonomic ganglia Postganglionic neurons – from autonomic ganglia to effectors organs Neurons can synapse to more than one other neuron at a time.  Pregangliac neurons emerge from the lumbar and thoracic spinal regions,  Arranged in 3 possible patterns: First: MOST COMMON: short axon from lateral horn ­> spinal nerve, branches off and  synapses in ganglia. Second: Long pregangliac neurons innervate endocrine tissure (wide spread sympathetic) Third: pregangliac neurons synapse with postgangliac neurons (in pairs, celiac ganglia – stomach, liver, spleen) – Inferior(lg.intestine, kidney, bladder) & superior (sm. Intestsine,  upper lg. intenstine) Parasympathetic NS – Anatomy: ­ Neurons originate from the brainstem/sacral spinal cord ­ Pregangliac neurons are long, terminate near organ cranial nerves: vagus nerve, oculomotor nerve, facial nerve, glossopharyngeal nerve Contrast form sympathetic: preganglionic neurons originating form the spinal cord do not  join with the spinal nerve. Autonomic Neurotransmitters and Receptors: Neurotransmitter: 2 Primary: acetylcholine and norepinephrine. Two types of Neurons within these systems: Cholinergic Neurons:  release acetylcholine, pregangliac neurons of sympathetic and parasympathetic Adrenergic Neurons: Release norepineprhine, almost all sympathetic postgangliac neurons Both types of neurotransmitters can bind to different classes and subclasses of cholinergic and adrenergic receptors, respectively. Cholinergic: Nicotinic: 4 subclasses: Cell bodies and dendrites of sympathetic and parasympathetic ganglionic neurons Chromafin cells and skeletal muscles. Cation channels, depolarization of postsynaptic cell Excitatory Muscarinic: 5 Subclasses, effector organs of parasympathetic nervous system G protein coupled, excitatory or inhibitory Autonomic Neurotransmiters and Receptors 2 Major Classes: ineffector organs of sympathetic nervous system -alpha and beta ­ coupled to G protein, activating or inhibiting second messenger systems ­ a receptors have greater sffinity for epinephrine, inhibitory response ­ B1, B3 receptors have equal affinities for norepinephrine and epinephrine, mostly excitatory Autonomic Nervous System: Neuroeffector Junction -a synapse between an efferent nrueon and effector organ -a synapse between postganglionic neurons and effector organs do not have discrete axon terminals -neruotransmitters released from varicosities Visceral reflexes – autonomic changes in the functions of your organs in response to internal body conditions. E.g. Reflex arc of standing up.(when u stand up a change of blood pressure occurs…why you get a little light headed when you stand up too fast) Regulation of Function – BrainAreas ­ Hypothalamus: Fight or flight, sympathetic activation, body temp. food intake, H2O Balance. ­ Pons and Medulla Oblongata: respiratory and cardiovascular regulatory centers present. E.g. heart blood vessles, smoth muscle of respiratory airways Motion Sickness: Nausea, sweating, difficulty standing upright Caused by a mismatch or sensory inputs -vestibular apparatus visual system propriocepters throughout the body. BOTH branches of the autonomic NS. Scopolamine – muscarinic cholinergic antagonist can counteract motion sickness. (drug to help) Somatic Nervous System -controls the skeletal Muscles -only one single type of efferent neuron – Motor neurons -the voluntary Nervous System Anatomy: Single motor neuron travels from the CNS to skeletal muscle where it innervates. (only one signal per muscle fiber cell) a single motor unit = neuron and fiber cells it innervates. Neuromuscular Junctions -the region where the branch of the motor neuron synapse at a skeletal muscle fiber -axon terminals are called terminal boutons( store and release acetylcholine) Motor endplate: opppostie to terminal boutons in PM of muscle fiber. Contains nicotinic cholinergic receptors within invaginations These “Junctions” are vulnerable and a termed “target sites” to animals that inject venom. Latroxin- black widow spider, causes muscle spasms = respiratory failure Crotoxin- in rattlesnakes, paralysis of skeletal muscles = no contractions Curare: -paralyzing effects on skeletal muscle posin used on dart tips used in blow guns. Blocks communication at neuromuscular junction, binds to the nicotinic cholinergic receptors, skeletal muscles do not receive signal to contract  CLINICAL USES TODAY: Dialation of the throat, rectum Spastic paralysis relief Midterm Review: (Chapters 1-11, 21) 80% Multiple Choice (definition oriented) 5-10% matching terms/fill in the blank 5-10% labeling a diagram: Focus on: Epithelial/membrane structure layout, Major areas of the brain (lobes etc.) Neurons/structure/of diff types (axonal transport microtubules) Cell structures/ organelles, membranes, etc. Sensory structures/eyes (3 layers of the retina, lens etc.) & ears layout (inner outer ears) Some nasal anatomy (mucus glands, structures) Spinal Column (anatomy/later, dorsal horns etc.) 5-10% ShortAnswer: ­ “compare and contrast x vs. y”Alternating proceses –e.g. sympathetic and parasympathetic neurons. ­ Procces q’s, signal Na+ K+,, excocytosis. ­ Cell membrane transport ­ References to clinical uses, functionalities etc. Epithelial Membrane/ Structure Layout: Made up of connective and epithelial tissue, these serve as lining coverings for various  body structures. ­­­­­­­­­­­­­­­­­­­­­­­­­­­READING  WEEK­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­ No Lecture 8 Lecture 9 – Chapter 12, 13  Muscular Physiology and Cardiovascular system: Final exam: 21 December 7pm (35%) The somatic nervous system innervates skeletal muscle The autonomic nervous system innervates smooth muscle, cardiac muscle Q: How are the action potentials here different from what we learned about in neurons?? A: muscle contraction = physical contraction = end point Rather than a chain reaction of signals flowing through synaptic cells “excitable” Muscle Cells: high energy cells = lots of ATP Anaerobic glycolysis = how they get there E Skeletal  Muscle: formed during embryonic development ­ connected to at least 3 bones ­ biceps, triceps, gastrocnemious etc. ­ tendons connect muscle to bone ­ EXCEPTIONS: those connecting to skin, cartilage, facial muscles,  connecting to larynx etc. Muscles consist of: The body : “meaty” force generating component Epimysium: surrounding connective tissue, holds muscle fibers together Going deeper…. ­ Perimysium divides muscles into “bundles” Muscle fibers aka cells, run the length of the muscle (fused cells 
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