1979 1982 1983 1984 1985 1986 1986b 1987 1989 1990
ANIMAL SYSTEMS QUESTION 1979: L. PETERSON/ECHS Describe the structure and function of the stomach, pancreas, and small intestine as digestive and endocrine organs in the human. (For each organ, include the relevant cell types and their functions.) STANDARDS: [1 point for each statement unless otherwise indicated] Stomach (max. 7 points) STRUCTURE: Regions = cardiac, fundic, pyloric / pyloric sphincter (1 pt. for 2 of 3) Layers of muscle; thick walls Presence of RUGAE (cellular composition = histology) DIGESTIVE FUNCTION: Mention chief cells and parietal cells OR Name and function of chief cells - secrete renin, lipase, pepsinogen Name and function of parietal cells - secrete HCl Presence of mucous coat protects the stomach Function of HCl = aids protein digestion OR converts pepsinogen to pepsin Pepsin - produced in inactive form to protect OR its function in protein digestion Churning aids mechanical digestion Absorption of alcohol, etc. in stomach ENDOCRINE FUNCTION: Name and function of gastrin = stimulates production of digestive juice Presence of Food = stimulus for gastrin release Factors such as stress effects gastrin/stomach function Small Intestine (max. 7 points) STRUCTURE: Increased surface area by folds or villi or microvilli Structure of villi = blood vessels, lymph Regions = duodenum, jejeunum, ileum DIGESTIVE FUNCTION: Name 3 enzymes from intestinal glands (peptidases, sucrases, enterokinase, lipase, amylase, nuclease) Function of each enzyme (max. 2) Bile released in small amounts plus: a) produced in the liver or b) stored in gall bladder or c) emulsifier Site of most absorption Mechanical absorption of long fatty acids Peristalsis Change in pH ENDOCRINE FUNCTION: Secretin /function = stimulates release of alkaline secretions by pancreas Enterogasterone /function = inhibits stomach Cholecystokinin /function = stimulates gall bladder to release bile Pancreozymin /function = stimulates pancrease to secrete digestive enzymes Enterokinin /function = stimulates intestinal glands to secrete enzymes Pancreas (max. 7 points) STRUCTURE: Connects to small intestine by pancreatic duct Comprised of exocrine and endocrine cells DIGESTIVE FUNCTION: Secretion of pancreatic juice and digestive function of enzyme mixture OR Name 3 enzymes in pancreatic juice: amylase, trypsinogen, chymotrypsin, carboxypeptidase, lipase Function of each pancreatic enzyme (max. 2) Secretion of bicarbonate ions to neutralize ENDOCRINE FUNCTION: Mention of Islets of Langerhans - function in glucose metabolism Alpha cells secrete glucagon Glucagon stimulates liver to convert glycogen to glucose Beta cells secrete insulin Insulin stimulates uptake of glucose by cells
ANIMAL SYSTEMS QUESTION 1982 L. PETERSON/ECHS Describe the following mechanisms of response to foreign materials in the human body. a. The antigen-antibody response to a skin graft from another person. b. The reactions of the body leading to inflammation of a wound infected by bacteria. STANDARDS: [1 point for each statement] * = additional points occasionally encountered ANTIGENS- REJECTION Recognition as foreign antigens Rejection by Immune System Antigens on surface of graft cells *Surface glycoproteins as Antigens Antigens stimulate Antibody production or T-cells ANTIBODIES Lymphocytes - B Lymphocytes B Lymphocytes (Antigen Exposure) -> Plasma Cells Plasma cells synthesize Antibodies *Antibodies are Globulins (Immunoglobulins) Types = IgG, A, M, D, E Antibodies are proteins Antibodies remain in circulatory system Antibody structure Antibodies circulate to sites needed Antibodies precipitate Antigens or complex w/Antigens Antibodies make Antigens susceptible to phagocytosis by WBCs Antibody variability due to genes / Clonal Selection Theory Antibody specificity - broad/narrow Antibodies important in both graft rejection and in fighting bacteria, etc. T - CELLS T -cells involved in cell mediated immunity Lymphocytes -> T -cells *T -cells: thymus involvement as "helper" cells COMPATIBILITY Tissues / Graft must be compatible / Tissue matching Blood groups as examples of compatibility Genetic basis of compatibility *Tolerance / Immunosuppression MEMORY Memory cells Secondary Response *Complement = serum proteins acts by Antibody-Antigen Complex complement inactivates or kills bacteria WBCS WBCs invade inflection site - destroy bacteria or wall-off Phagocytosis *WBCs types: neutrophils, basophils, eosinophils, monocytes; lysosomes in phagocytic WBCs macrophages WBCs from marrow bacterial presence -> WBC production PUS/FLUIDS Pus = WBCs, Dead Cells, etc, Fluids, plasma -> swelling Inflammed area = hot (kills bacteria) Lymphatic System Filters CLOT Clot walls-off inflammed area Clotting Mechanism - some detail DILATION Dilation of Blood Vessels increases circulation; WBCs *Histamines -> Dilation Histamines from mast cells CHEMOTAXIS WBCs accumulate /"message" calls WBCs to inflammed site *Kinin - chemotactic or increases dilation
ANIMAL SYSTEMS QUESTION 1983 L. PETERSON/ECHS Describe the structure of a mammalian respiratory system. Include in your discussion the mechanisms of inspiration and expiration. STANDARDS: 21 points possible - max. = 15 [must include description &/or function to get point] DESCRIPTION - STRUCTURE 1 - Nasal Chambers - hard/soft palate, cilia, mucous membranes Sinuses - air spaces, sensory receptors 1 - Pharynx - eustachian tube, tonsils 1 - Larynx - vocal cords, epiglottis 1 - Trachea - cartilaginous rings 1 - Bronchial tree - bronchioles 1 - Lungs - pleural membranes 1 - Alveoli - site of gas exchange, thin-walled 1 or 2: 2 - Sequential Listing of 5 or more portions of system 1 - Incorrect sequence or less than 5 organs MECHANISMS - INSPIRATION 1 - Diaphragm - contraction, goes down 1 - Intercostal muscles 1 - Thoracic cage - outward and upward 1 - Negative pressure (Concept) MECHANISMS - EXPIRATION 1 - Passive recoil (Concept) 1 - Thoracic and abdominal muscles 1 - Thoracic cage - downward and inward 1 - Diaphragm - goes upward NEURAL CONTROL 1 - Medulla 1 - Inspiratory center 1 - Expiratory neuron, inhibition 1 - pH
ANIMAL SYSTEMS QUESTION 1984 L. PETERSON/ECHS Discuss the sources and actions of each of the following pairs of hormones in humans and describe the feedback mechanisms that control their release. a. Insulin..glucagon b. Parathyroid hormone..calcitonin c. Thyrotropin (TSH)..thyroxine (T4) STANDARDS: Maximum of any 6 points on each of three sections. Must answer all three sections of exam to score 15. Discretionary point on adequate discussion of feedback loop and/or homeostasis. INSULIN/GLUCAGON SECTION INSULIN: SOURCE 2 - Beta cells of pancreas 1 - Pancreas or Islets of Langerhans ACTION 1 - Lowers blood sugar 1 - Promotes glucose oxidation in cells 1 - Glycogen synthesis (liver and muscle) RELEASE 1 - Chemical - blood glucose level 1 - Hormonal - secretin, gastrin, etc. 1 - Neural - Acetylcholine (parasympathetic) stimulates GLUCAGON: SOURCE 2 - Alpha cells of pancreas 1 - Pancreas or Islets of Langerhans ACTION 1 - Increases blood glucose 1 - Stimulates glycogen -> glucose (liver) 1 - Synthesis of glucose from amino acids and fatty acids RELEASE 1 - Level of blood glucose, i.e. low glucose / increases glucagon 1 - Neural - Autonomic system PARATHYROID HORMONE/CALCITONIN SECTION PARATHYROID HORMONE: SOURCE 1 - Parathyroid gland on posterior surface of thyroid ACTION 1 - Control of Ca (inc.) and P (dec.) level 1 - Acts on bones, kidneys, and intestine 1 - Increases activity of osteoclasts (Ca and P bone -> blood) 1 - Kidney Ca reabsorbed, P excreted RELEASE 1 - Blood Ca low, PTH high (vice-versa) CALCITONIN: SOURCE 1 - Cells in thyroid gland ACTION 1 - Decreases osteoclast activity 1 - Inhibits release of Ca and P from bone 1 - Lowers blood Ca and P RELEASE 1 - Increased blood Ca causes increase in Calcitonin THYROTROPIN/THYROXINE SECTION THYROTROPIN SOURCE 1 - Anterior Pituitary ACTION 1 - Stimulates thyroid hormone synthesis and secretion 1 - Increases iodide binding, T3, T4 synthesis 1 - T3, T4 release RELEASE 1 - Thyroid Hormone level decreases, TSH increases (vice-versa) THYROID HORMONE SOURCE 1 - Follicles of thyroid gland or thyroid gland ACTION 1 - Maintains metabolic level 1 - Increases O2 consumption 1 - Maintains normal development and function RELEASE 1 - Neural via hypothalamus (low thyroid hormone, increases TSH) 1 - TSH feedback (thyroid and anterior pituitary
ANIMAL SYSTEMS QUESTION 1985 L. PETERSON/ECHS Describe the anatomical and functional similarities and differences within each of the following pairs of structures. a. Artery..vein b. Small intestine..colon c. Skeletal muscle..cardiac muscle d. Anterior pituitary..posterior pituitary STANDARDS: 15 point maximum - must answer all four parts for 15 A. ARTERY-VEIN (7 points possible - 4 points maximum) 1 - Wall thickness or lumen - relate to blood pressure 1 - 3 layers identify or elaborate 1 - Valves in veins - function 1 - Direction of flow 1 - O2/CO2 concentration - mention of pulmonary circulation 1 - Capillary relationship - hydrostatic or osmotic pressure 1 - Pulsating/elasticity - explanation of pressure B. SMALL INTESTINE-COLON (8 points possible - 4 points maximum) 1 - Villi - function - increase in absorption 1 - Length - diameter - size comparison or elaboration 1 - Glands of intestine - Digestive vs. mucous 1 - Regions - elaboration 1 - Smooth muscle - peristalsis 1 - Three tissue layers - elaboration 1 - Absorption - food materials, water, salts, mention of surface area 1 - Flora - comparison/explanation C. SKELETAL-CARDIAC MUSCLE (7 points possible - 4 points maximum) 1 - Location - explanation 1 - Nervous control - voluntary/involuntary 2 - Appearance - Similarities ex. striations / actin-myosin, etc. Differences ex. discs / branching, etc. 3 - Physiology (Comparisons) ex. contraction / refraction / ions / specific nerves / nodes, etc. D. ANTERIOR-POSTERIOR PITUITARY (8 points possible - 4 points maximum) 1 - Origin - mouth - brain 1 - Location - hypothalamus - connection to brain 1 - Control - anterior/hormonal; posterior/nervous 2 - Hormones (list and explain 2 or more) 6 anterior: FSH, LH, ACTH, TSH, somatotropin, prolactin 2 posterior: ADH, oxytocin 1 - Anterior production / Posterior storage 1- Endocrine - elaboration or definition 1 - Feedback mechanism
ANIMAL SYSTEMS QUESTION 1986: L. PETERSON/ECHS Describe the processes of fat and protein digestion and product absorption as they occur in the human stomach and small intestine. Include a discussion of the enzymatic reactions involved. STANDARDS: STOMACH: GENERAL POINTS 1 - no absorption in the stomach 1 - mechanical breakdown occurs in the stomach 1 - protection of the stomach 1 - chyme (definition) 1 - chyme is in stomach for several hours (implied) 1 - mention of the stomach being acidic due to HCl 1 - parietal cells produce HCl / chief cells produce pepsinogen 1 - gastrin (hormone) 1 - hydrolysis (definition) PROTEIN POINTS 1 - HCl - pepsinogen -> pepsin 1 - pepsin--protein -> polypeptide FAT POINTS 1 - very little digestion of fat in the stomach SMALL INTESTINE: GENERAL POINTS 1 - pH becomes more basic 1 - secretin (hormone) ABSORPTION 1 - occurs in small intestine 1 - microvilli 1 - villi 1 - increase surface area 1 - amino acids -> capillary or amino acid absorption products 1 - amino acids 1 - fatty acids -> lacteals or lymphatic 1 - glycerol -> capillaries 1 - fatty acids by diffusion PROTEIN POINTS 1 - trypsinogen/trypsin 1 - chymotrypsinogen/chymotrypsin 1 - peptidase/di/tripeptidase 1 - endopeptidase (within molecule) 1 - exopeptidase (terminal end of molecule) 1 - protease 1 - pancreas / intestinal gland 1 - protein/polypeptide -> amino acid FAT POINTS 1 - bile (liver - gall bladder) 1 - cholecystokinin (hormone) 1 - emulsify (definition) 1 - lipase/pancreas 1 - lipase function: lipids -> fatty acids and glycerol 1 - Na bicarbonate
ANIMAL SYSTEMS QUESTION 1986b: L. PETERSON/ECHS Beginning at the presynaptic membrane of the neuromuscular junction, describe the physical and biochemical events involved in the contraction of a skeletal muscle fiber. Include the structure of the fiber in your discussion. STANDARDS: Presynaptic (must be a motor neuron) 1 - Nature of impulse +++ --- 1 - Increase of permeability of Ca 2+ 1 - Movement of vesicles 1 - Fusion of vesicles with membrane 1 - Transmitter release 1 - Acetylcholine 1 - Diffusion of transmitter (20 nm) 1 - Cholinesterase 1 - Motor end plate or terminal bouton Postsynaptic (muscle be a muscle fiber) A. Transmitter Effects 1 - Specific receptor sites 1 - Causes depolarization/action potential 1 - Action potential sweeps fiber membrane/T. tubules 1 - Release of Ca 2+ from Sarcoplasmic reticulum (T. cisternae) B. Calcium Effects 1 - Calcium floods sarcomere 1 - Calcium binds to troponin 1 - Bound troponin displaces tropomyosin 1 - Calcium returned by active transport (Ca2+ pump) C. Actinomyosin Complex 1 - Binding sites actin exposed by tropomyosin displacement 1 - Myosin cross bridges bind actin 1 - ATP used 1 - Power stroke, recovery flip 1 - ATP needed to separate actin-myosin 1 - Rigor Mortis D. Other 1 - Sliding Filament Theory 1 - Diagram/explanation contracted muscle 1 - Muscle twitch, tetany, fatigue 1 - Lactic acid, O2 debt 1 - Creatine phosphate--ATP Muscle Fiber Structure 1 - Definition 1 - Characteristics 2 - Striations, banding multi-nucleated, many mitochondria 1 - Myofibrils (as sub-units) 1 - Sarcomere (as unit of myofibril) 1 - Sarcoplasmic reticulum (cell membrane, etc.) (terminal cisternae) 1 - T. tubules (cell membrane connection, etc.) 1 - Banding Pattern (explain or diagram) 1 - Actin/myosin (protein or thin, thick, etc.) 1 - Actin a globular protein 1 - Myosin a linear protein w/cross bridges 1 - Troponin/tropomyosin associated with actin
ANIMAL SYSTEMS QUESTION 1987: L. PETERSON/ECHS Discuss the exchange of oxygen and carbon dioxide that occur at the alveoli and muscle cells of mammals. Include in your answer a description of the transport of these gases in the blood. STANDARDS: EXCHANGE (8 points max.) 1 - O2/CO2 diffusion or correct direction of O2/CO2 gas movement 1 - concentration gradient or explanation 1 - Alveoli/membrane characteristics (large surface area, or thin-walled, or "grape clusters", or sacs, or surrounded by capillaries) 1 - moist surface necessary for exchange 1 - interstitial fluid role in transport 1 - P O2/CO2 description 1 - Illustrated curve on graph or explanation 100 mm Hg lungs 40 mm Hg muscles (rest) 20 mm Hg muscles (exercise) 1 - temperature effects 1 - further explanation as: (tissues) higher temperatures -> less affinity OR (lungs) lower temperatures -> more affinity OR graph 1 - CO2 in plasma lowers pH of blood 1 - Bohr effect - acidity affects affinity of Hb for O2 1- example lower pH -> less affinity higher pH -> more affinity OR graph 1 - myoglobin in muscle stores O2 (greater affinity for O2) 1 - air is approximately 20% oxygen 1 - other hemoglobin adaptations, such as: (maternal-fetal or low altitude-high altitude) TRANSPORT (8 points max.) OXYGEN 1 - carried by hemoglobin or in red blood cell 1 - hemoglobin found in red blood cell 1 - hemoglobin characteristics such as: protein, or 4 subgroups, or Heme, or iron and porphyrin ring 1 - Hb cooperativity (allosteric) - one O2 increases affinity for others S-shaped curve 1 - CO can compete with O2 for Hb binding site CARBON DIOXIDE - 1 - majority carried as bicarbonate ions (HCO3) 1 - enzyme carbonic anhydrase speeds reactions - 1 - CO2 + H2O <--> H2CO3 <--> H+ + HCO3 1 -some CO2 carried aqueously (dissolved) 1- some CO2 carried by Hb (on a different site - does not compete with O2) 1 - Hb picks up H+ ions to buffer blood CIRCULATORY TRANSPORT PATHWAY 1 - from alveolus to muscle cell (pulmonary vein -> left atrium -> left ventricle -> artery -> capillary) 1 - from muscle cell to alveolus (capillary -> vein -> right atrium -> right ventricle -> pulmonary artery)
ANIMAL SYSTEMS QUESTION 1989: L. PETERSON/ECHS Describe negative and positive feedback loops, and discuss how feedback mechanisms regulate each of the following: a. The menstrual cycle in a nonpregnant human female b. Blood glucose levels in humans STANDARDS: Introduction: (describe -/+ feedback loops) 1 pt 1. Definition as an overview of the process: Control mechanism which is regulated through the effect it brings about. 1 + 1 pts 2. Negative feedback: Endproduct acts as an inhibitor of pathway (stimulatory- inhibitory). Seek terms such as inhibit/turn off. Examples: ACTH -> cortisol -> feedback; Lac operon; thermostat metaphor; CO2 respiration, etc. 1 + 1 pts 3. Positive feedback: change in variable amplifies the pathway (stimulatory- stimulatory). Seek terms such as turn on/stimulate/induce. Examples: Oxytocin/birth; LH surge; trypsinogen/trypsin; neural membrane permeability; mating process; sound amplification metaphor; etc. [one point for definition and one point for example] Note: these points might be embedded in Parts A and B. Total of 3 points maximum for introduction out of 5 points possible. Part A: Menstrual Cycle 1 pt 1. Primary function of the cycle as an overall concept: production of gamete and preparation of the uterus. A borad interpretation OK. 1 + 1 + 1 pts 2. Hormones and interactions: look for information that suggests cause and effect and a pathway. Items a-c are complete examples. To earn a point, three targets, hormones, and sources must be given in a logical sequence. Wrong information will void a string of three. The goal is to find physio- logical relationships and not just terms. a. GnRH (hypothalamus) -> FSH (pituitary) -> estrogen (ovary) -> endometrium b. GnRH (hypothalamus) -> LH (pituitary) -> progesterone (corpus luteum) -> endometrium c. estrogen -> LH surge -> ovulation Research on the regulation of the menstrual cycle is rapidly evolving and textbooks can reflect different philosophies or progress of research. 1 or 2 pts 3. Negative feedback results on hypothalamus/pituitary. Estrogen/progesterone inhibits FSH and LH production at the GnRH (hypo- thalamus) and pituitary level. If no choriogonadotropic hormone -> estrogen/ progesterone levels drop and endometrium stimulus no longer supported - > endometrium lost as cycle begins again and FSH and LH released from inhibition. [2 points for completeness] 1 pt 4. Positive feedback: estrogen -> LH surge. Note: estrogen can be both inhibitory and stimulatory on the hypothalamus/pituitary. Total of 5 points maximum for Part A out of 7 points possible. Part B: Blood Sugar 1 pt 1. Concept of homeostasis, equilibrium, and/or maintenance of glucose level. 1 pts 2. Concept of antagonistic relationship of glucagon and insulin. 1 + 1 pts 3a. Low blood glucose -> glucagon release -> glycogen converted to glucose/ glucose mobilized from liver to blood or alpha cells in pancreas release glucagon 1 + 1 pts 3b. High blood glucose -> insulin release - glucose mobilized into cells -> lower blood levels/glucose mobilized into liver or muscle or beta cells of pancreas release insulin 1 pt 4. Alternate loops of blood glucose levels (only one point possible here): a. adrenalin, noradrenalin b. ACTH, cortisol c. somatostatin Total of 5 points maximum for Part B out of 7 points possible.
ANIMAL SYSTEMS QUESTION 1990: L. PETERSON/ECHS A. Describe the differences between the terms in each of the following pairs. (1) Coelomate versus acoelomate body plan (2) Protostome versus deuterostome development (3) Radial versus bilateral symmetry B. Explain how each of these pairs of features was important in constructing the phylogenetic tree shown below. Use specific examples from the tree in your discussion. Chordata Arthropoda Annelida Echinodermata Mollusca Nematoda Rotifera Platyhelminthes Cnidaria Porifera STANDARDS: A. (1) COELOMATE VS. ACOELOMATE 1 - Coelomate: internal body cavity lined with mesoderm (not sufficient to say: "true body cavity") 1 - Acoelomate: lacking internal cavities altogether or having: a pseudocoelom (Nematoda and Rotifera) a spongocoel (Porifera) mesoglea (Cnidaria) a solid layer of mesoderm (Platyhelminthes) [Max. = 2 / must define both for full credit] (2) PROTOSTOME VS. DEUTEROSTOME DEVELOPMENT 1 - Protostome: mouth develops near/at the blastopore or anus forms secondarily (later), OR featuring: spiral cleavage (micromeres between macromeres); determinate/mosaic development (blastomere fate is established at very early stages of development); mesoderm from cells that migrate into the blastocoel near blastopore schizocoelous coelomation (internal split in solid wedge of mesoderm that is independent of gut); trochophore larva; 1 - Deuterostome: anus develops near/at the blastopore or the mouth forms secondarily (later), OR featuring: radial cleavage (micromeres directly above macromeres); indeterminate/regulative development (blastopore fate is variable and not established until late in development); mesoderm arises from outpocketings of the gut; enterocoelous coelomation (outpocketings of gut); dipleurula larva [Max. = 2 / must define both for full credit] (3) RADIAL VS. BILATERAL SYMMETRY 1 - Radial: several planes passing through the long or central axis can divide the organism into similar parts. 1 - Bilateral: (only) one plane passing through the long axis divides the organism into similar right and left sides -- exhibits cephalization. 1 - Echinoderms: bilaterally symmetrical larvae, but appear to have radially symmetrical adult forms. [Max. = 2] B. PHYLOGENETIC TREE 1 - for examples of contrasting pairs (phyla or organisms) using terms from above; answer here or in part A. 1 - for using above terms in explanation of why phyla are in separate groups (or separate branches) of the tree. 1/1 - Body symmetry (cephalization) permits separation of Porifera and Cnidaria (radially symmetrical) from other phyla (bilaterally symmetrical). 1/1 - Coelomation permits separation of Platyhelminthes, Nematoda, and Rotifera from other phyla above Cnidaria: flatworms are acoelomate, whereas those other than nematodes and rotifers are coelomate. 1/1 - Origin of the mouth and anus permit separation of Echinodermata and Chordata (deuterostomes) from Arthropoda, Annelida, and Mollusca (protostomes). [Some include Platyhelminthes, Nematodes, and Rotifers as protostomes.] 1 - Nematodes and rotifers are grouped separately because both are pseudocoelomate. 1 - Phylogenetic trees based taxonomic relationships on homologous structures, patterns of embryonic development, and common ancestry. [Max. = 6]