1. You are recording an action potential from an unidentified nerve. Which of the following is true?

A. By looking at the shape of the action potential you can determine that you are recording from a motor neuron.
B. The action potential is a graded potential
C.* You can not distinguish the type of nerve you are recording from by looking at the action potential.
D. You can only recorded action potentials from glial cells.
E. No two action potentials would ever look the same.

2. During an action potential the following events occur.

A. Voltage gated sodium channels open and sodium flows out of the cell.
B. Voltage gated sodium channels open and sodium flows into the cell.
C. Voltage-gated potassium channels open and K flows out to repolarize the cell.
D. Both A. and C. occur
E.* Both B. and C. occur

3. Synaptic transmission occurs between a neuron and another neuron, or a muscle or a gland. Which statement about synaptic transmission is incorrect?

A. Most synaptic transmission is chemical.
B. In chemical synapses the synaptic cleft is 20 nm and is the distance a neurotransmitter must diffuse.
C. Receptors on the post synaptic cell determine if a response is excitatory or inhibitory.
D.* Calcium is not needed for synaptic transmission.
E. It is important to remove a neurotransmitter from the synaptic cleft after it has been used for synaptic transmission.

4. You are studying synaptic transmission by recording from a post-synaptic neuron. Under control conditions you stimulate the presynaptic neuron and record an EPSP in the post-synaptic cell. You have discovered a new compound from an exotic rain forest plant that prevents the fusion of synaptic vesicles with the presynaptic membrane. How will this drug affect your recordings?

A. There will be no effect.
B. You will now record an IPSP.
C.* You will record no post synaptic potential.
D. You will enhance the size of the EPSP.
E. You will increase the duration of the EPSP.

5. In class we discussed three organizing principles for understanding nervous systems: divergence, convergence and reflex arcs. Which of the following statements is true?

A.* In convergence a target cell receives the sum of information from many presynaptic cells.
B. In divergence a target cell receives the sum of information from many presynaptic cells.
C. A reflex arc involves many responses to sensory stimuli. It involves the brain and complex processing.
D. Interneurons are basically sensory neurons and have receptors that interact directly with the environment.
E. None of the above (A. - D.) is true.

6. Myelin has the following function.

A.* It helps increase the speed at which an action potential travels.
B. It prevents the neuron from heating up after an action potential.
C. Neurotransmitters are synthesized in the myelin.
D. Myelin has no known function.
E. The voltage-gated sodium channels that underlie an action potential are located in the myelin.

7. Rod, cone and ganglion cells are involved in which sensory system.

A. Chemoreception
B. Mechanoreception
C.* Photoreception
D. Thermoreception
E. Pain reception

8. All sensory systems have a common plan. Which statement about sensory systems is incorrect?

A. Receptor potentials are graded.
B. Sensory systems can adapt.
C. The strength of a stimulus is encoded in the frequency of the action potentials it produces.
D.* The strength of a stimulus is encoded in the size of the action potentials it produces.
E. Sensory receptors detect changes in a stimulus.

9. Steroid and nonsteroid hormones are similar because they both

A. activate genes that lead to the synthesis of new proteins.
B. bind with receptors on the plasma membrane of target cells.
C. use second messengers to activate enzymes in the cytoplasm of target cells.
D.* are chemical messengers that are distributed to non-adjacent target cells by the circulatory system.
E. B. and C. both make correct statements.

10. Parathyroid glands secrete a hormone, PTH, that stimulates bone cells to release calcium and also activates vitamin D which enhances calcium absorption from ingested food. From your general understanding of the control of hormone secretion, which one of the following statements is most likely to be correct?

A. PTH release is stimulated when bones grow too large.
B. The secretion of PTH is inhibited when bones lose too much calcium.
C. According to the principle of negative feedback control, PTH secretion is stimulated when the calcium concentration in the blood drops below normal, homeostatic levels.
D.* According to the principle of negative feedback control, PTH secretion is inhibited when the calcium concentration of the blood increases above normal levels.
E. Parathyroid glands require iodine to function properly.

11. Which of the following statements is(are) true?

A. The posterior pituitary peptides oxytocin and ADH are neurohormones secreted by hypothalamic neurosecretory cells.
B. Endocrine cells in the anterior pituitary secrete releasing hormones that act on other endocrine glands.
C. A special portal system carries releasing hormones from the hypothalamus to the anterior pituitary.
D.* A. and C.
E. B. and C.

[Note: A. was also accepted for version 0 of the exam, since the textbook does not define the term "portal."]

12. The medulla of the adrenal gland develops from neural tissue. In response to a "threatening" situation, cells of the adrenal medulla produce ______ and secretion is controlled by ______.

A. cortisol; ACTH (adrenocorticotropic hormone)
B.* epinephrine (adrenaline) and norepinephrine; sympathetic nerves.
C. cortisol; ACh (acetylcholine)
D. epinephrine and norepinephrine; ACTH

13. _____ muscle tissue occurs in the walls of many internal organs except the heart.

A. Skeletal
B. Cardiac
C.* Smooth
D. Striated
E. Autonomic

14. According to the sliding filament model of muscle contraction,

A.* if a resting muscle fiber is "overstretched" so that its thin and thick filaments do not overlap at all, the sarcomeres cannot contract when the muscle fiber stimulated.
B. thick and thin filaments shorten up to 70% during sarcomere contraction.
C. cross bridges that form between adjacent myosin molecules provide the energy that causes actin filaments to shorten.
D. thin filaments slide past thick filaments during sarcomere contraction because troponin molecules push the Z lines towards each other.
E. myosin heads attach to actin binding sites and bend in a power stroke that pulls thin filaments away from the center of the sarcomere.

15. The ATP needed for contraction of skeletal muscle during prolonged, moderate exercise

A. is provided mainly by an anaerobic pathway (lactate fermentation) in which glucose is broken down to lactate.
B. is provided mainly by aerobic respiration.
C. is derived first from the breakdown of glucose that comes from the glycogen stored inside the muscle fibers, and later from glucose and fatty acids delivered by the bloodstream.
D. is derived mainly from the dephosphorylation of creatine phosphate.
E.* both B. and C. make correct statements.

16. Blood provides an internal bulk transport system that carries nutrients, gases and waste products from sites of absorption or production to sites of utilization or excretion. It is composed of water, solutes (including proteins and ions), cells, and formed elements. What is not found in blood?

A. hormones
B. glucose
C. antibodies
D.* glycogen
E. platelets

17. In humans a blood cell initially found in the right pulmonary vein will encounter which part of the circulatory system next?

A. left ventricle
B. capillary in the right lung
C. right pulmonary artery
D.* left atrium
E. right atrium

18. When one listens to the heart with a stethoscope, two main heart sounds can be heard, lub-dup, which repeat rhythmically [...lub-dup...lub-dup...lub-dup...etc.]. The first heart sound, lub, is low-pitched, not very loud, and fairly long-lasting. It is caused mainly by the _______, and marks the beginning of _______.

A. closing of the semilunar valves (aortic and pulmonary valves); ventricular systole
B.* closing of the AV valves; ventricular systole
C. closing of the AV valves; ventricular diastole
D. contraction of the ventricles; ventricular systole
E. closing of the semilunar valves; ventricular diastole

19. The lymphatic system picks up excess fluid from the tissues and removes unwanted biota and cellular debris from the lymph. Where does the "excess fluid" come from?

A. It is produced in the bone marrow.
B. It is secreted by tissue cells.
C. It is absorbed across the wall of the small intestine whenever we take a drink of water.
D.* It leaks out of the capillaries due to hydrostatic pressure of the blood.
E. It is pulled out of the capillaries due to the high osmotic pressure of the interstitial fluid.

20. When we inhale,

A.* the size of our thoracic (chest) cavity increases due to contraction of our respiratory muscles.
B. the pressure within the lungs is less than the pressure within the thoracic cavity.
C. our diaphragm contracts causing it to move upward and become more curved.
D. all the oxygen in the air in our alveoli diffuses into our blood.
E. all of the above (A. - D.) make correct statements

21. Rate and depth of breathing in humans is controlled by respiratory centers in the reticular formation of the brain that signals our breathing muscles to contract and relax. The respiratory centers receive input from sensory receptors that monitor . They cause us to breath faster and more deeply .

A. our heartrate; whenever our heartrate increases
B. the concentration of O2 in our blood; when the partial pressure of O2 in our lungs declines
C.* the concentration of hydrogen ions in our blood; when the pH of our blood declines
D. the partial pressure of CO2 in our blood; when the concentration of H2CO3 (carbonic acid) in our blood declines
E. blood pH; when blood pH increases

22. Which of the following statements regarding gas exchange and transport in humans is (are) true?

A.* Carbon dioxide in metabolically active tissue diffuses into the blood because the partial pressure of carbon dioxide is higher in the tissue fluid than in the blood entering the capillaries.
B. Carbon dioxide diffuses into the blood because its partial pressure is greater at the start of the systemic capillaries than at the start of the systemic veins.
C. Most of the oxygen carried in the blood to body tissues is bound to red blood cell membranes.
D. Almost all of the carbon dioxide transported in the blood is either dissolved in plasma or bound to hemoglobin.
E. C. and D.

23. The pancreas is an accessory organ of the digestive system that

A. secretes insulin and glucagon into the digestive tract to aid in the breakdown of polysaccarides.
B. secretes enzymes into the digestive tract that help break down all major food macromolecules.
C. secretes bicarbonate into the small intestine to neutralize HCl from the stomach.
D.* B. and C. make correct statements
E. A., B. and C. all make correct statements

24. Most enzymatic digestion takes place in the

A. mouth (oral cavity)
B. stomach
C.* small intestine
D. large intestine
E. liver

25. Products of the digestive process such as monosaccarides and amino acids, are absorbed in the _____ by means of active transport or facilitated diffusion and pass into ______ . Triglycerides are reassembled inside intestinal cells, are packaged into chylomicrons and enter ______.

A. stomach; blood capillaries; the lymph system
B.* small intestine; blood capillaries in intestinal villi; lymph vessels in the villi
C. stomach; the small intestine; blood capillaries in intestinal villi
D. large intestine; blood capillaries; lymph vessels
E. villi; the interstitial fluid; blood capillaries in microvilli

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