Midterm 2Name: __________________________Biology 449 - Animal Physiology Spring 2007Midterm 2 Fill in your scantron form as follows:- Write and bubble in your name in the upper left (last name first).- Follow any additional instructions provided in class.- Sign your form on the upper right. By so doing you verify that you are abiding by Creighton’s policy on academic honesty.Multiple choice: As always, choose the best answer for each multiple-choice question. Answer on your scantron form. Each question is worth 3 points.1. Paracrine agents reach their target cells viaa. diffusionb. transport in vesicles.c. transport in the bloodstream.d. transport in the lymph.e. transport through ducts.2. In which chemical category do most known hormones fall?a. Aminesb. Glycoproteinsc. Peptide hormonesd. Prostaglandinse. Steroid hormones3. Which of the following mechanisms can change the amount of hormone being released by a gland?a. Changes in the action potential frequency in neurons that innervate the gland.b. Changes in the levels of a tropic hormone that affects the gland.c. Detection by the gland itself of changes in the internal environment.d. Two of the above.e. All of the above.4. The main response to cortisol (in natural animal populations) could best be described as helping to ensure that an animala. can keep fueling cellular activity when it may have limited access to food.b. deposits large fat stores in case future access to food is limited.c. has increased its metabolic rate to a level that can support increased activity.d. has adequate blood flow to essential tissues when faced with dangerous conditions.e. does not get infected with a pathogen when it can least afford it.15. Given what you know about thyroid hormones, which of the following is the most likely mechanism by which they help increase Na+/K+-ATPase activity?a. The hormones bind to and activate Na+/K+-ATPases already present in the cell membrane.b. The hormones activate G-protein complexes that directly activate Na+/K+-ATPases already present in the cell membrane.c. The hormones activate G-protein complexes that activate secondary messengers that activate Na+/K+-ATPases already present in the cell membrane.d. The hormones activate G-protein complexes that activate secondary messengers that promote the insertion of stored Na+/K+-ATPase into the cell membrane.e. The hormones cause the increased production of mRNA for Na+/K+-ATPase, which leads to the production and insertion of additional ATPase.6. Which of the following terms best describes the general changes or activities promoted by growth hormone?a. Increased metabolic rateb. Decreased metabolic ratec. Increased catabolic activityd. Increased anabolic activitye. Increased sex hormone levels7. In muscle fibers, the myofibrils are composed of the main functional units of contraction. These units are known as a. sarcolemmas.b. sarcomeres.c. sarcoplasms.d. sarcoplasmic reticuli.e. sarcotrons.8. Cross-bridge cycling in muscles involvesa. reversible binding between actin and myosin, and changes in conformation of the myosin.b. reversible binding between actin and myosin, and changes in conformation of the actin.c. reversible binding between myosin and tropomyosin, and changes in conformation of the myosin.d. reversible binding between myosin and tropomyosin, and changes in conformation of the tropomyosin.e. mysterious forces beyond the power of humankind to understand.2f. The dihydropyridine receptors in the T-tubules of skeletal muscle active ryanodine receptors as part of the process triggering muscular contraction. The dihydropyridine receptors themselves are triggered byg. neurotransmitter molecules.h. changes in the diameter of the T-tubules.i. changes in membrane potential.j. the presence of Ca2+.k. the absence of Ca2+. 9. In general, the heavier the load a muscle is lifting during a twitch contractiona. the less time it is able to lift the load.b. the more slowly it lifts the load.c. the less distance it lifts the load.d. Two of the above.e. All of the above.10. In comparison to slow oxidative muscle fibers, fast glycolytic muscle fibers tend to havea. higher capillary density.b. slower rates of fatigue.c. more glycogen (the stored form of glucose).d. more mitochondria.e. more myoglobin.11. To control the amount of sustained force they produce, muscles rely ona. the partial activation of each muscle fiber.b. alternation between twitch and tetanic contractions.c. opposing forces produced by antagonistic muscles.d. activation of only some muscle fibers in the muscle.e. reduced delivery of fuel to muscle fibers.12. The blood vessels that experience the highest pressure are the a. systemic arteries.b. systemic arterioles.c. pulmonary arteries.d. pulmonary arterioles.e. capillaries.3f. Action potentials in the sinoatrial node of the heart would not occur without g. stimulation by the sympathetic nervous system.h. stimulation by the endocrine system.i. stimulation by action potentials that are triggered by the atrioventricular node.j. stimulation by action potentials from stretch receptors in the heart wall.k. The sinoatrial node depolarizes spontaneously, without the need for external stimulation.13. Starling’s Law of the Heart states thata. The heart beats more quickly in response to decreased ventricular filling.b. The heart beats more quickly in response to increased ventricular filling.c. The heart ejects more blood in response to decreased ventricular filling.d. The heart ejects more blood in response to increased ventricular filling.e. If you hear a starling sing under a full moon, you are destined to meet your true love.14. If the arterioles leading to the gastrointestinal tract were to dilate, which of the following patterns would you most likely see as a result?a. Increased bloodflow to the GI tract, and increased cardiac output and/or increased vasoconstriction elsewhere.b. Increased bloodflow to the GI tract, and decreased cardiac output and/or decreased vasoconstriction elsewhere.c. Decreased bloodflow to the GI tract, and increased cardiac output and/or increased vasoconstriction elsewhere.d. Decreased bloodflow to the GI tract, and decreased cardiac output and/or decreased vasoconstriction elsewhere.e. You would probably start vomiting up blood.15. Which of the following substances can diffuse straight through the cell membranes of the capillaries’ endothelium? a. glucoseb. Na+c. proteinsd. oxygene. None of the above can diffuse straight