SOLUTION
Cadet APPROVED ________________________ Time of Departure __________
DEPARTMENT OF CHEMISTRY AND LIFE SCIENCE CH387 Human Physiology Written Partial Review 1 (C/D hours) 12 February 2007 Resources Permitted: None Text: Principles of Human Physiology, Germann & Stanfield Available time: 55 minutes
CHECK THIS EXAMINATION TO SEE THAT THERE ARE 8 PAGES, NOT INCLUDING THE COVER PAGE. INFORM THE INSTRUCTOR OF ANY INCOMPLETE OR MISSING PAGES. WRITE YOUR NAME ON THE TOP OF EACH SHEET. ANSWER ALL QUESTIONS.
TOTAL WEIGHT 200 POINTS
DO NOT WRITE IN THIS SPACE:
PART 1 2 TOTAL
MAX VALUE 126 74 200
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POINTS
APPROVED SOLUTION PART 1 (126 Points) MULTIPLE CHOICE: (3.5 points each) 1. (3) What type of gland secretes products into ducts leading to the external environment? a. b. c. d. endocrine glands exocrine glands both A and B neither A and B
2. (1) Homeostasis is a term which describes the process whereby the body __________. a. b. c. d. maintains a constant external environment affects the external environment maintains a variable internal environment maintains a constant internal environment
3. (2) What separates the internal environment of the body from the external environment? a. b. c. d. skin
membranes of blood cells epithelium plasma membrane of all body cells
4. (1) The plasma membrane of cells is composed of a. b. c. d. membranous and nonmembranous organelles. an epithelial layer. a phospholipid bilayer with imbedded proteins. the cytoskeleton.
5. (2) Which of the following is NOT a primary type of tissue? a. b. c. d. e. muscle skeletal nerve epithelial connective
6. (1) An enzyme and a substrate molecule that bind tightly together are said to have a. b. c. d. low affinity. covalent regulation. equilibrium. high affinity.
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7. (3) __________ is a reflection of the unequal distribution of positive and negative ions across the plasma membrane. a. b. c. d. Chemical gradient Extracellular potential Membrane potential Chemical driving force
8. (3) An example of primary active transport is a. b. c. d. transport of Ca+2 ions up an electrochemical gradient by a protein. transport of glucose molecules down a concentration gradient by carriers. movement of Ca+2 ions down an electrochemical gradient through ion channels. transport of glucose molecules up a concentration gradient by a protein that couples glucose flow to the flow of Na+ down an electrochemical gradient.
9. (2) Which of the following cells would have a greater electrical attraction for sodium ions to enter the cell? a. b. c. d. cell with membrane potential = -90 mV cell with membrane potential = -70 mV cell with membrane potential = 0 mV cell with membrane potential = +20 mV
10. (2) What will occur if a cell (with a 300 mOsm solute concentration) is placed in a 100 mOsm solution? a. b. c. d. The cell will swell. The cell will shrink. The osmolarity of the solution will decrease to 50 mOsm. Voltage gated ion channels will open.
11. (3) Glucose entry into cells is influenced by the a. b. c. d. electrochemical driving force. membrane potential. chemical driving force. electrical driving force.
12. (1) Vesicles formed during phagocytosis often fuse with the membrane of which of the following organelles? a. b. c. d. Golgi complex endoplasmic reticulum mitochondria lysosome
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13. (1) In order to terminate a cAMP-mediated response, the enzyme ________ can be activated to degrade cAMP. a. b. c. d. phosphodiesterase protein kinase phospholipase phosphoprotein phosphatase
14. (2) ________________ have the ability to elicit marked responses in target cells, known as signal amplification, due to the fact that one extracellular signal molecule results in the activation of many intracellular molecules. a. b. c. d. Receptor mediated messengers Second messenger systems Enzyme-linked receptors Ion channels
15. (1) A secondary endocrine organ is _____________________. a. b. c. d. an organ that secretes at least two hormones. an organ that secretes hormones, but is better known for another function. an organ that secretes tropic hormones. an organ that is the target of tropic hormones.
16. (3) Pain relief resulting from rubbing a painful area is explained by a. b. c. d. two-point discrimination. referred pain. gate-control theory. lateral inhibition.
17. (2) Which of the following affects the concentration of free hormone in the blood? a. b. c. d. rate of hormone secretion amount of hormone transported bound to proteins rate of metabolism all of the above
18. (1) In the postabsorptive state, the central nervous system uses which of the following as its primary source of energy? a. b. c. d. glycerol amino acids ketones glucose
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19. (2) The blood-brain barrier a. allows simple diffusion of hydrophobic and hydrophilic molecules. b. protects the central nervous system by restricting glucose from crossing plasma membranes. c. protects the central nervous system by restricting movement of molecules across capillary endothelial cells. d. is responsible for the same chemical composition of the cerebrospinal fluid and that of plasma. 20. (1) Tropic hormones regulate the a. b. c. d. secretion of other hormones. action of neurons. secretion of neurotransmitters. second messenger system.
21. (1) ________ is/are the functional unit of the nervous system. a. b. c. d. Neurons Glial cells Axons The central nervous system
22. (2) Repolarization of an axon during an action potential is produced by a. b. c. d. inward diffusion of Na+. inward active transport of K+. outward diffusion of K +. inward active transport of Na+.
23. (2) Sensory receptors are associated with what functional class of neurons? a. efferent b. afferent c. interneuron 24. (3) During the absorptive state a. we are in positive energy balance and energy is stored. b. the primary energy source for our muscles glycogen. is c. the rate of energy intake is less than the rate of energy expenditure and thus the breakdown lipid for energy is required. d. the concentration of growth hormone and thyroid hormones in the blood increase significantly.
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25. (1) Summation involves the addition of a. action potentials. b. graded potentials. c. stabilizing resting membrane potential. 26. (1) A characteristic of action potentials is that a. b. c. d. they can be either small or large. they are all-or-none. they involve hyperpolarization by not depolarization. they propagate in myelinated axons but not unmyelinated axons.
27. (1) The presynaptic neuron contains synaptic vesicles which release a. b. c. d. Insulin. Na+. neurotransmitters. steroids.
28. (3) A change in a cell's membrane potential, such that it becomes more positive, is referred to as a _________________. a. b. c. d. hyperpolarization hypopolarization repolarization depolarization
29. (1) All spinal nerves contain a. b. c. d. afferent fibers. efferent fibers. both afferent and efferent fibers. neither afferent nor efferent fibers.
30. (3) A chemical that inactivates acetylcholinesterase a. b. c. d. inhibits the release of ACh from presynaptic endings. causes constant stimulation of muscle contraction. causes decreased stimulation of muscle contraction. inhibits the attachment of ACh to its receptor protein.
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31. (1) Different types of sensory information (modalities) are detected by a. specific receptors. b. one type of receptor. c. all cells of the body. 32. (1) The arrow (pictured to the right) is pointing to what part of the brain? a. b. c. d. cerebrum corpus callosum cerebellum hypothalamus
33. (2) A reflex, such as a stretch reflex, involves a. b. c. d. efferent neurons. afferent neurons. interneurons. all of the above.
34. (3) The spinal cord a. b. c. d. does not contain neuron cell bodies, but only nerve fibers. contains gray matter ascending tracts and white matter descending tracts. contains both myelinated and unmyelinated nerve fibers. is protected by flexible cartilage.
35. (3) Neurotransmitter release occurs by what mechanism? a. b. c. d. exocytosis endocytosis diffusion primary active transport
36. (1) _________ is the primary neurotransmitter released from motor neurons. a. Epinephrine b. Norepinephrine c. Acetylcholine d. Dopamine
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PART 2 (74 Points) 1. (12) Describe three differences between simple diffusion and primary active transport of material across a biological membrane. Simple diffusion: (1) molecules travel down their concentration gradient, (2) no free energy is required, and (3) no transport protein in cell membrane is required Primary active transport: (1) molecules move up the concentration gradient, (2) free energy in the form of ATP is required, and (3) a transport protein in the cell membrane is required. 2. (14) Describe in detail the components of the cAMP second messenger system and how it causes a response in a cell. The first messenger outside the cell binds to the cell membrane receptor and activates a Gs protein. The G protein releases the subunit, which binds to and activates the enzyme adenylate cyclase. Adenylate cyclase catalyzes the conversion of ATP to cAMP. cAMP activates protein kinase A, which catalyzes the transfer of a phosphate group from ATP to a protein, thereby altering the protein's activity. The altered protein activity causes a cellular response.
3. (12) Describe three factors that control the concentration of hormone in the blood. The concentration of hormone in the blood is controlled by 1) rate of hormone secretion, 2) amount of hormone bound to plasma proteins, and 3) rate of hormone metabolism.
4. (12) Describe the role of insulin during the absorptive state. Insulin promotes the uptake of glucose by cells and the synthesis of energy storage molecules during the absorptive state. As glucose levels rise in the bloodstream after a meal, the Beta cells of the pancreas secrete insulin into the bloodstream. Insulin regulates energy storage by stimulating the synthesis of fatty acids and triglycerides in the liver and adipose tissues, glycogen in the liver and skeletal muscle, and proteins in most tissues.
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5. (12) Once an action potential is generated, there is a delay before another action potential can be generated. Name and describe the basis for the two refractory periods. Absolute refractory period: a duration of time following the initiation of an action potential in which a second action potential can not be generated. This is because the inactivation gates of the sodium channel are closed and cannot be reopened by a second stimulus. It spans all of the depolarization phase of the action potential and most of the repolarization phase. Relative refractory period: a duration of time when a second stimulus can initiate an action potential, but that stimulus must be suprathreshold. This is caused by increased potassium permeability of the membrane and opening of the inactivation gate in a portion of the sodium channels.
6. (12) Compare and contrast graded potentials and action potentials. Graded potentials are small changes in membrane potential that are relatively weak and proportional to the strength of the stimulus from sensory receptors. Action potentials are large changes in membrane potential of axons. Graded potentials are relatively weak and dissipate with distance from stimulus while action potentials work on the all-or-none principle. Graded potentials are subject to spatial and temporal summation, while action potentials do not display summation. Graded potentials have no refractory period, while action potentials have absolute and relative summation.
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