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Chapter 3

Bio 1080 ch.3a (iv), (v), 3b (i)

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BIOL 1080
Dr.Bill Bettger

Bio 1080 Ch.3a (iv), (v), 3b (i) Adrenal glands (ad, upon; renal, kidney) - Located at the tops of the kidneys - Has outer region: adrenal cortex; secretes more than 20 different lipid-soluble hormones (mineralocorticoids, gonadocorticoids and glucocorticoids) - inner region: adrenal medulla; secretes 2 water-soluble hormones (epinephrine and norepinephrine) Adrenal cortex  Gonadocorticoids: male and female sex hormones 1) Androgens; effects in adult males are insignificant 2) Estrogens; produced by ovaries and placenta. During menopause, stop secreting it  Mineralocorticoids: secreted by the adrenal cortex affect mineral homeostasis and water balance 1) Aldosterone; acts on cells of the kidneys to increase reabsorption of Na+ into the blood (prevents depletion of Na+ and increases water retention). Also acts on kidneys cells to promote the excretion of K+ in urine - Addison’s disease caused by under secretion of aldosterone and glucocorticoid cortisol (autoimmune disorder). Can also be caused by inadequate secretion of ACTH by the pituitary 2) Glucocorticoids; hormones secreted by the adrenal cortex that affect glucose levels. Acts on the liver to promote the conversion of fat and protein to intermediate substances that re ultimately converted into glucose, act on adipose tissue to prompt the breakdown of fats to fatty acids that are available for use by the body’s cells. Conserve glucose by inhibiting its uptake by muscle and fat tissue - inhibit the inflammatory response; slowing the movement of white blood cells to the site of injury - Cushing’s syndrome results from prolonged exposure to high levels of glucocorticoid cortisol Adrenal medulla  Epinephrine and norepinephrine (critical in fight-or-flight response); reaction by the body’s sympathetic nervous system to emergencies -prolong the response of the sympathetic nervous system to stress Pancreas -Located in the abdomen just behind the stomach (contains both endocrine and exocrine cells) 1) Endocrine cell occur in small clusters “pancreatic islets”  Produces glucagon  Produces insulin  Produces somatostatin; also secreted by the digestive tract, inhibits secretions of the stomach and small intestine. And by hypothalamus, where it inhibits secretion of growth hormone. May regulate secretion of glucagon and insulin - when level of blood sugar declines, pancreas secretes glucagon, stimulate the liver to form glucose from lactic acid and amino acids. Prompting cells of the liver to increase conversion of glycogen to glucose - insulin decrease glucose in the blood. 1) It stimulates transport of glucose into muscle cells, white blood cells and connective tissue cells. 2) It inhibits the breakdown of glycogen to glucose 3) It prevents conversion of amino and fatty acids to glucose (promotes protein synthesis, fat storage and use of glucose for energy) - type 1 diabetes: juvenile-onset; injection of insulin (diet and exercise essential) - type 2 diabetes: insulin-dependent diabetes (decreased sensitivity to insulin, need exercise, diet restrictions and weight loss), need insulin injections , obesity and high blood pressure - insulin shock; severe depletion of blood glucose (can prove fatal unless blood sugar levels are raised) Thymus gland - lies just behind the breastbone, on the top of the heart (decreases in size as we age) - secretes thymopoietin and thymosin, that promotes the maturation of white blood cells called T lymphocytes Pineal gland - tiny gland at the center of the brain - secretory cells produce the hormone melatonin (greater at night than in day light because of inputs from visual pathways received) - neurons of retina stimulated by light send impulses to the hypothalamus and the pineal gland - melatonin may; inhibit production of pigment melanin by melanocytes of the skin, influence daily rhythms and slow aging process. - too much melatonin: seasonal affective disorder, less exposure to light due to winter hours. Locally acting chemical messengers - Local signaling molecules; act near the site of their release, on adjacent target cells, communication via these molecules occurs rapidly than carried out by hormones, travels to distant sites within the body (e.g. neurotransmitters, prostaglandins, growth factors and nitric oxide) 1) Prostaglandins: lipid molecules continually released by plasma membranes of most cells, affect the reproductive system (menstrual cramps caused by release or prostaglandins by cells of the uterine lining; aspirin inhibit the synthesis of prostaglandins) 2) Growth factors: peptides or proteins that, when present in the fluid outside target cells, stimulate those cells to grow, develop and multiply. (e.g. 1. causes precursor cells in the bone marrow to proliferate and differentiate into particular white blood cells. 2. Prompts endothelial cells to proliferate and organize into tubes that eventually form blood vessels) 3) Gas nitric oxide: functions in the cellular communication that leads to the dilation of blood vessels. - Endothelial cells of the inner lining of blood vessels make and release NO; signals the smooth muscles in the surrounding layer to relax, allow vessel to dilate, Function as a neurotransmitter, carrying messages from one neuron to the next Terms Oxytocin: second hormone produced in the hypothalamus and released by the posterior pituitary (stimulating the uterine contractions of childbirth, stimulates milk ejection from mammary glands) Functions and mechanisms of hormones - endocrine glands: made of secretory cells that release their products; hormones (moves from cell that produced them to fluid outside the cells where they diffuse in bloodstream  pituitary gland, thyroid gland, parathyroid glands, adrenal glands and pineal gland  organ with endocrine tissue; hypothalamus, thymus, pancreas, ovaries, testes, heart and placenta, stomach, small intestine and kidneys - endocrine system: endocrine glands and organs that contain some endocrine tissue (regulate and coordinate other body system and maintain homeostasis, leisurely system coordinate and regulate long term process; growth, development and reproduction)  Hormones as chemical messengers - hormones: chemical messengers of endocrine system, release in small amount by cells of endocrine glands and tissues and enter bloodstream to travel throughout the body, affect mostly target cell - target cells have receptors, protein molecules that recognize and bind to specific hormones, once it binds to specific hormones, hormone receptors complex begins to exert its effects on the cell, cells lack correct receptors; unaffected by hormone - mechanisms by which hormones influence target cells depend on chemical makeup of hormone (lipid soluble or water soluble) - lipid-soluble hormones (steroid hormones): group of related hormones derived from cholesterol (organs that secrete steroid; ovaries, testes and adrenal glands),  move easily through any cell’s plasma membrane because it is a lipid bilayer  inside target cell, steroid combines with receptor molecule in cytoplasm, hormone-receptor then move into nucleus of cell, where it attaches to DNA and activates genes, leads target cell to synthesize specific proteins (include enzyme that stimulate particular metabolic pathways - water-soluble hormones (protein or peptide hormones), cant pass through lipid bilayer or membrane and cannot enter target cells  Hormone (first messenger) binds to receptor on plasma membrane of target cell activates molecule (second messengers in cytoplasm; molecule within cell that influence activity of enzyme and activity of cell to produce effect of hormone e.g. cAMP)  Binding of epinephrine to receptor on plasma membrane of liver cell prompts conversion of ATP to cAMP, which activates enzyme within the cell (protein kinase) and other enzymes… this cascade activation of enzyme that catalyzes breakdown of glycogen to glucose  Activate protein already in cell  Feedback mechanisms and secretion of hormone 1. negative feedback mechanism; homeostasis mechanisms in which outcome of a process feeds back to the system shutting the process down - regulate secretion of some hormone - gland releases hormone and then rising blood levels of hormone inhibit its release - insulin prompts liver to store glucose; blood level glucose declines, pancreas senses low glucose in blood; stops secreting insulin, maintained with narrow range 2. positive feedback mechanism; secretion of hormones sometimes regulated by this; outcome of process feeds back to the system and stimulates process to continue - during childbirth; pituitary gland releases hormone oxytocin OT; stimulates uterus to contract which stimulates release of more oxytocin (positive since it acts to stimulate rather than inhibit release of OT), expulsion of baby and placenta terminate cycle - during stress, heavy bleeding or starvation; nervous system permits levels of blood glucose to rise higher than normal; gives cells access to large amount of energy for coping with stress  role of hypothalamus and pituitary gland in hormone signaling - hypothalamus send the nerve signaling and the neurohormone to tell pituitary gland to produce GH Bio 1080 Ch.3a (v) p. 182-188 The body’s defense system  Bacteria, viruses, protozoans, fungi, parasitic worms and prions that causes disease are pathogens Three lines of defense 1) Keep the foreign organisms or molecules out of the body in the first place: chemical and physical surface barriers 2) Attack any foreign organism or molecule or cancer cell inside the body: internal cellular and chemical defenses 3) Destroy a specific type of foreign organism or molecule or cancer cell inside the body: immune response 1) Physical and chemical barriers  Physical: - Unbroken skin helps shield the body from pathogens by providing a barrier to foreign substances - layer of dead cells forms the tough outer layer of skin, filled with fibrous protein keratin, which waterproofs the skin and makes it resistant to the disruptive toxins and enzymes, invaders. - mucous membranes lining the digestive and respiratory track, produces sticky mucus that traps microbes and prevent from entering the body. Have cilia, beat the contaminated mucus to the throat (swallowing, coughing or sneezing)  Chemical: - sweat and old produced by glands in the skin wash away microbes - acidity of secretions slows bacterial growth and the oils contain chemicals that kill some bacteria - include the lining of the stomach , produces hydrochloric acid that destroy many pathogens - acidity of urine slows bacterial growth - saliva and tears contain an enzyme “lysozyme” that kills bacteria by disrupting their cell walls 2) Defensive cells and proteins, inflammation, and fever  Defensive cells: - phagocytes engulf pathogens, damaged tissue or dead cells by the process if phagocytosis - front-line soldiers in the body’s internal defense system and janitors that clean up debris 1. Neutrophils: arrives at the site of attack before the other types of white blood cells and begins to consume the pathogens; bacteria, by phagocytosis 2. Macrophages: white blood cell transform into large macrophage. Hearty and less discriminating appetites than neutrophils do, attack and consume anything that is not recognized as belonging in the body (viruses, bacteria and damaged tissue) 3. Eosinophils: attacks pathogens that are too large to be consumed by phagocytosis (parasitic worms), gets close to the parasite and discharge enzymes that destroy the organism  Natural killer cells: - roams the body in search of abnormal cells and quickly orchestrates their death - kill many invading organisms and cancer cells  Defensive proteins: 1. Interferons: act to slow the spread of viruses already in the body, interfere with viral activity 2. Complement system: stimulates histamine release  promotes phagocytosis (first attract macrophages and neutrophils to the site of infection to remove the foreign cell. Second binds to the surface of the microbe)  kills bacteria (punching holes in target cells membrane, so the cell is no longer able to maintain a constant internal environment, water enters the cell causing it to burst)  enhances inflammation (provide increased blood flow to the area and increased access for white blood cells)  Inflammation: Widening of blood vessels and increased capillary permeability, leading to redness, heat, swelling and pain. Bring in defensive cells and speeds healing. - redness: occurs because blood vessels dilate in the damaged area, causing blood flow in this area to increase, caused by histamine release by mast cells - heat: increased metabolic rate of cells in the injured area to speed healing - swelling: fluid containing defensive chemicals, blood-clotting factors, oxygen, nutrients, and defensive cells seeps into the injured area -pain: hampers movement allowing the injured area to heal  Fever:  Abnormally high body temperature, caused by pyrogens, chemicals that raise the thermostat in the brain to a higher set point. Slows the growth of bacteria; speeds up body defenses. 3) Immune response - provides the specific responses and memory. Organs of the lymphatic system are important components of the immune system; produce the various cells responsible for immunity - recognizing and destroying specific pathogens or foreign molecules -immune response: body’s specific defenses working together - 1. directed at a particular pathogen -effective immune system will enable the child to recover from the illness -2. Has memory, remembers pathogen and attacks it - MHC markers: flags declaring the cell as a friend, named for major histocompatibility complex genes that code for them - hay fever or allergic rhinitis: common allergy (not caused by hay and does not cause fever), sneezing and nasal congestion, occur when allergen is inhaled, trigger immune system in respiratory system - in Systemic lupus erthematosus: connective tissue attacked, can cause skin lesions or rashes (butterfly-shaped rash, may affect heart joint, kidneys or nervous system Secondary immune system - following subsequent exposure to an antigen is swifter and stronger than the primary response (difference is due to long lived memory cells produced during primary response; larger pool of lymphocytes programmed to respond to particular antigen Autoimmunity - immune system fails to distinguish between self and nonself and attacks the tissues or organs of the body - lymphocyte attack specific antigen while tolerating self antigens, some do not learn this distinction and are destroyed, but some escape destruction - organ specific; directed against 1 organ (caused by T cells that have gone awry) e.g. hashimoto’s thyroiditis - non organ specific; caused by antibodies produced by B cells gone awry and have effects in body e.g. systemic lupus erythematosus (skin lesion, rashes, butterfly rash, affect heart, joints, kidneys or nervous system) - occurs because disease-causing organisms resemble proteins found on normal body cells. If immune system mistakes body antigens for foreign antigens, may attack them - body attack streptococcal bacteria causes sore throat may result in production of antibodies that target this bacteria but other similar molecules in valves of heart and joints; rheumatic fever Active and passive immunity 1. Active immunity - body defends itself by producing memory B cells and T cells after exposure to antigen - naturally when we get infections and can develop through vaccination - leads to production of memory cells; occurring in vaccination or naturally is long- lived 2. Passive immunity - protection that result when a person antibodies produced by another person or animal (pregnant woman, some antibodies cant cross placenta and will remain in baby’s bodies as long as 3 months after birth, in breast milk (fight pathogens that might enter baby intestinal lining) - mother antibodies = blanket protection for the baby; most pathogens that threaten health of newborn encountered by mother’s immune system - can acquire by being injected with antibodies; effects immediate, protection short lived Bio 1080 Ch. 3b (i) p.202-238 Functions of blood  carries vital materials to all the cells of the body and carriers away the wastes that cells produce  white blood cell help protect us against disease-causing organisms and its clotting mechanisms help protect us from excessive blood loss when a vessel is damaged  buffer in blood help regulate acid-base balance of body fluids  blood regulate body temperature by absorbing heat produced  3 categories: transportation, protection and regulation  transport CO2 from the cells where it is produced to the lungs for release Composition of blood Plasma  straw-colored liquid that makes up 55% of blood  medium in which materials are transported by the blood  (almost every substance transported by the blood is dissolved in plasma)  Nutrients, ions, dissolved gases and every hormone  carries away cellular wastes  plasma protein are most of the dissolved substances in the blood (7 or 8% of plasma)  help balance water flow between the blood and the cells  without plasma proteins, water would be drawn out of the blood by the proteins in cells; water would accumulate in tissue swelling 3 categories of plasma proteins 1. Albumins: make up more than half of plasma proteins, important in blood’s water balancing ability 2. Globulins: some transport lipids (fat, cholesterol, fat soluble vitamins). Other are antibodies; provide protection against many diseases 3. Clotting: fibrinogen Formed elements  Platelets, white blood cells and red blood cells  Red bone marrow, porous connective tissue that fills the cavities within may bones; birth place and nursery for formed elements  Sponge like framework- supports fat cells, undifferentiated cells; stem cells that divide and give rise to all formed elements Platelets (thrombocyte)  essential to blood clotting  fragments of larger cells – megakaryocytes (small purple-stained granules in cytoplasm) and are formed in the red bone marrow when megakaryocytes break apart, fragment release into blood at the astounding rate of about 200 billion a day  mature during a week, after circulate in the blood for about 5- 10 days  contains substance in stopping the loss of blood through damaged blood vessels  # of cells/mm3  250 000 – 500 000 White blood cells (or leukocytes) and defense against disease  remove wastes, toxins and damaged or abnormal cells  serve as warriors in the body’s fight against disease  1% of whole blood  produced in the red bone marrow, nucleated  can leave the circulatory system and move to site of infection, tissue damage or inflammation  chemicals release by invading microbes or damaged cells attract them and cause them to gather in areas of tissue damage or infection  certain types may engulf the offender in a process called phagocytosis 2 group of white blood cells 1. Granulocytes; have granule in cytoplasm (contains chemicals that are used as weapons to destroy invading pathogens; bacteria)  Neutrophils:  Small granule that don’t stain with either red stain eosin or with basic blue stain  Consume bacteria by phagocytosis  Multilobed nucleus, clear-staining cytoplasm, inconspicuous granules  # of cells/mm3 3000 – 7000  life span: 6 – 72 hours  blood cell soldiers  after engulfing a dozen- it dies, but still helps the body’s defense by releasing chemicals that attract more neutrophils  Eosinophils:  Granules pink up color pink from stain eosin in cytoplasm, bilobed nucleus  Consume antibody-antigen complex by phagocytosis; attack parasitic worms; tapeworms and hookworms  # of cells/mm3 100 – 400  life span: 8 – 12 days  lessen the severity of allergies by engulfing antibody-antigen and inactivating inflammatory chemicals  Basophils:  Large purple-staining granules, cytoplasmic granule; bilobed nucleus  Release histamine, which attracts white blood cells to the site of inflammation and widens blood vessels , increasing blood flow to the affected area  # of cells/mm3 20 – 50  life span: 3 – 72 hours  play a role in some allergic reactions 2. Agranulocytes: lack cytoplasmic granules or have very small granules  Monocytes:  give rise to macrophages, which consume bacteria, dead cells, and cell parts by phagocytosis  gray-blue cytoplasm with no granules; U-shaped nucleus  # of cells/mm3 100 – 700  life span: several months  leave the bloodstream and enter various tissue  Lymphocyte:  attack damaged or diseased cells, or disease-causing organisms; produce antibodies  round nucleus that almost fills the cell  # of cells/mm3 1500 – 3000  life span: many years  B-lymphocyte: give rise to plasma cells, which, in turn produces antibodies (proteins that recognize specific molecules- antigens) on the surface of invading microbes. After recognizing the microbes, antibodies help prevent it from harming the body  T-lymphocyte: specialized white blood cells that play roles in the body’s defense mechanisms Red blood cells (erythrocytes) and transport of oxygen  pick up oxygen in the lungs and ferry it to all the cells of the body, carry CO2  # of cell/mm3 4-6 million, 45% of blood volume  life span: 120 days, travels ~ 100 km of blood vessels Red blood cells and hemoglobin  great surface area oxygen can enter more rapidly than if the disk did not have an indent  each red blood cell is packed with hemoglobin, oxygen-binding pigment that is responsible for the cells’ red color  Hemoglobin made of 4 subunits, consist of a polypeptide chain and a heme group; iron ion binds to oxygen. Can carry up to 4 molecule of oxygen; oxyhemoglobin  Binds 200 times more readily to CO, that is why it is deadly. When CO binds to the oxygen-binding sites on hemoglobin, blocks oxygen from binding to it, prevent blood from carrying life-giving oxygen to the cells. Life cycle of red blood cells 1. Change in shape 2. Cell leaves bone marrow and enter the bloodstream (produc
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