BIO203 Exam 2

How many ova are produced from a single primary oocyte?

1

Do the following statements describe actin, myosin, both of the proteins or neither of the proteins? contains a binding site for calcium 1. found in the I band 2. exists in a globular (G) form and a filamentous (F) form 3. Contains a binding site for ATP 4. is a component of the thin filament 5. is a component of the thick filament A. actin B. myosin C. neither D. both

1. A 2. A 3. B 4. A 5. B

Match the following hormones with their appropriate chemical class 1. modified cholesterol molecules 2. cortisol 3. modified tyrosine molecules 4. epinephrine 5. short chains of amino acids 6. insulin A. steroid B. peptide C. amine

1. A 2. A 3. C 4. C 5. B 6. B

Match the following characteristics with the appropriate types of hormones 1. lipophobic 2. lipophilic 3. slow response time 4. rapid response time 5. GPCR 6. intracellular receptors A. peptide B. steroid

1. A 2. B 3. B 4. A 5. A 6. B

During contraction of skeletal muscle, how does the size of each of the following structures change? 1. A band 2. I band 3. H zone 4. sarcomere length 5. length of thick filaments 6. amount of overlap between thick filaments A. stays the same B. decreases C. increases

1. A 2. B 3. B 4. B 5. A 6. C

Match each cardiac valve with the two chambers it separates. Each pair of chambers may be used more than once, or not at all. 1. tricupsid 2. mitral 3. bicupsid 4. pulmonary semilunar 5. aortic semilunar A. right atrium and right ventricle B. left atrium and left ventricle C. right ventricle and pulmonary artery D. left ventricle and aorta E. right ventricle and aorta F. left ventricle and pulmonary artery

1. A 2. B 3. B 4. C 5. D

Match each perturbation of the skeletal muscle contraction cycle with the consequences it would cause. Each answer can be used only once. 1. Remove all ATP from the muscle fiber 2. Mutate myosin so that it would not be able to hydrolyze ATP and produce Pi or ADP 3. Deplete muscle cells of intracellular calcium A. Actin would remain strongly bound to myosin, the rigor state would be maintained. B. Myosin would be able to release actin, but the myosin head would not return to the "cocked position" and myosin would not rebind to actin. C. Tropomyosin would block the myosin binding sites on actin filaments and the power stroke would not occur

1. A 2. B 3. C

Match the descriptions with the correct phases of the ovarian cycle 1. progesterone levels are highest during this phase 2. menses occurs during the first part of this phase 3. LH levels peak during, or just before, this phase 4. This phase occurs approximately 14 days before the onset of menstruation 5. GnRH secretion is inhibited by estrogen secreted from the corpus luteum during this phase 6. This phase corresponds to the secretory phase of the uterine cycle 7. A follicle ruptures during this phase 8. The antrum of a follicle grows larger during the end of this phase A. Luteal phase B. Follicular phase C. Ovulation

1. A 2. B 3. C 4. C 5. A 6. A 7. C 8. B

Match the sensory characteristic with how it is coded by the nervous system. 1. Sensory Modality 2. Location of the stimulus 3. Intensity of the stimulus 4. Duration of the stimulus A. Which sensory neurons are activated B. Receptive fields C. Frequency of action potentials D. Duration of action potential train (i.e., continued firing of action potentials in sensory neurons) E. Size of action potential F. Duration of a single action potential

1. A 2. B 3. C 4. D

Match the following terms describing electrical events with the correct phases of the cardiac cycle. 1. The ventricular muscles depolarize at this phase 2. During this phase, Na+ entry through the funny channels causes the pacemaker potential of SA nodal cells to gradually become less negative until it reaches threshold. 3. The ventricular muscle cells repolarize right before this phase. 4. The cytosolic concentration of calcium in the contractile cells of the ventricle is highest during this phase. A. ventricular ejection B. isovolumetric contraction C. ventricular filling D. isovolumetric relaxation

1. B 2. C 3. D 4. A During the ventricular filling phase, the atria is getting read for contraction so the SA node will start becoming more depolarized as Na+ enters through the funny channels. Next, in order for contraction of the myocardium to take place, the ventricular muscle cells must start to depolarize during the beginning of the contraction phase. After the ventricles contract at the end of the isovolumetric contraction phase, the ventricles enter the ventricular ejection phase. During this phase, the cytosolic Ca++ concentration in the contractile cells are the highest in order to maximize the number of myosin-actin crossbridges formed. Next, the ventricles will repolarize after contraction and enter the isovolumetric relaxation phase and restart the cycle.

Match each glial cell type with the appropriate function. 1. Astrocytes 2. ependymal cells 3. microglia 4. oligodendrocytes 5. schwann cells A. form myelin in PNS B. help form the blood-brain barrier C. modified immune cells D. form myelin in CNS E. separate CNS fluid compartments

1. B 2. E 3. C 4. D 5. A

Match the descriptions with the correct types of motor units. 1. Recruited last 2. Contains Fast Muscle Fibers that use Aerobic respiration 3. Contains muscle fibers used for routine movements 4. Contains muscle fibers with the lowest myoglobin content 5. Contains muscle fibers with the slowest contraction speed 6. Have slow and relatively weak contractions A. Type I B. Type IIA C. Type IIB

1. C 2. B 3. B 4. C 5. A 6. A

Which divisions of the autonomic nervous system can cause changes in each of the following parameters? Choose the best answer. 1. Heart Rate 2. Stroke Volume 3. Arteriolar radius 4. Heart Contractility 5. MAP A. Parasympathetic B. Neither Parasympathetic nor Sympathetic C. Sympathetic and Parasympathetic D. Sympathetic

1. C 2. D 3. D 4. D 5. C Both the sympathetic and parasympathetic NS are involved in controlling the HR because there are ß1 and mACh receptors in the heart. Remember that stroke volume is the blood expelled via ventricular contractions. Only the SNS is involved in changing stroke volume because only ß1 receptors are found on ventricular contractile myocardium. This is the same reason heart contractility is controlled only by the SNS. Arteriolar radius is also controlled by the SNS because ß2 and α receptors are found the smooth muscles of blood vessels. The MAP is the average pressure in the arteries during the cardiac cycle, calculated by SV x HR. Since both the SNS and PSNS affect HR, they both affect MAP.

Match the following terms describing the physical/mechanical events with the correct phases of the cardiac cycle. Each phase may be used more than once. 1. All 4 cardiac valves are closed and all 4 chambers are relaxed during this phase 2. The maximum amount of blood is in the ventricles at the end of this phase. 3. The pressure in the ventricles is higher than in the atria, but lower than in the arteries, during this phase. 4. The semilunar valves are open and the AV valves are closed during this phase. 5. The atria contract at the end of this phase. 6. The pressure in the ventricles is higher than the pressure in both the atria and the arteries during this phase. 7. Systole begins with this phase A. ventricular filling B. isovolumetric contraction C. ventricular ejection D. isovolumetric relaxation

1. D 2. A 3. B 4. C 5. A 6. C 7. B

Match the sex organs with the structures they are derived from 1. ovary 2. testis 3. uterus 4. fallopian tubes 5. vas deferens 6. seminal vesicle 7. labia majora 8. scrotum A. wolffian duct B. bipotential external genitalia C. mullerian duct D. bipotential gonad

1. D 2. D 3. C 4. C 5. A 6. A 7. B 8. B

How many mature sperm are derived from a single primary spermatocyte?

4

What is the cardiac output if the HR is 75 and SV is 70? Answer in L/min

5.25 CO = HR x SV CO = 75 bpm x 0.070 L CO =

The hydrostatic pressure in a capillary is 32 mm Hg, and the plasma colloid osmotic pressure is 25 mmHg. What is the net filtration pressure, in mmHg?

7 Net filtration = Ph - π Net filtration = 32-25

What is the stroke volume is the end diastolic volume is 135 and end systolic volume is 65? Answer in mL

70 mL EDV - ESV = SV

Calculate the HR in beats per minutes if the cardiac cycle is 1 cycle in 800 ms

75 1 cycle / 800 ms = 1 beat per 0.8 s (60 s / 1 min) x (1 beat / 0.8 s) = 75 bpm

Select the MOST CORRECT answer. A. A motor neuron action potential always results in a skeletal muscle fiber action potential. B. Summation is able to occur in skeletal muscle due, in part, to the high number of voltage-gated sodium channels located in the end plate. C. Type 1 fibers have a higher number of voltage-gated sodium channels on the sarcolemma than Type 2B fibers, allowing 2B fibers to contract faster. D. both a) and b) are correct, and c) is incorrect E. a), b) and c) are all correct

A

Select the MOST CORRECT answer. An increase in end diastolic volume (EDV) will NOT cause... A. An increase in end systolic volume. B. An increase in stroke volume or cardiac output. C. An increase in mean arterial pressure. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

A

Regarding the human endocrine system (select the MOST CORRECT statement): A. Both arginine vasopressin (AVP) and oxytocin enter the circulatory system by diffusing through fenestrations in capillaries of the posterior pituitary. B. Portal blood vessels carry hypothalamic peptide hormones to the posterior pituitary. C. The gene that encodes cortisol is expressed in cells of the adrenal cortex. D. Both a) and b) are correct and c) is incorrect E. a), b) and c) are all correct

A AVP and oxytocin are both in vesicles and can be released to the circulatory system via diffusion through the capillaries. Portal blood vessels can carry hypothalamic hormones to the ANTERIOR pituitary.

Regarding mammalian nervous systems (select the MOST CORRECT statement): A. The medulla oblongata controls blood pressure, breathing, and other involuntary processes. B. Astrocytes participate in forming the blood brain barrier by extending cellular processes that wrap around cerebral arterioles. C. Oligodendrocytes form myelin in the peripheral nervous system. D. Both a) and b) are correct and c) is incorrect E. a), b) and c) are all correct

A Astrocytes wrap around capillaries not arterioles. The oligodendrocytes will form myelin in the CNS not the PNS (that is the Schwann cells)

How does norepinephrine influence mean arterial pressure? A. Increase MAP B. Decreases MAP C. Cause no net change in MAP

A Norepinephrine binds to α and ß receptors. The α receptors lead to the increase of intracellular Ca++ → ↑contractions → ↑resistance → ↑MAP. The ß receptors have the opposite effect. The α's effect is dominant so the overall effect is an increase in MAP.

Choose the INCORRECT statement A. Propagation of an action potential through the T-tubules into the sarcoplasmic reticulum triggers the release of Ca++ into the cytoplasm of a skeletal muscle fiber. B. The generation of suprathreshold endplate potentials in multiple muscle fibers could be due to the increased frequency of action potential generation at the axon hillock of a single motor neuron. C. A very small amount of ACh would be found in the neuromuscular synapse after exposure to Botulinum toxin, which blocks the formation of the SNARE complex proteins. D. The motor end plate membrane is only capable of generating graded potentials, but it is contiguous with the skeletal muscle sarcolemma, which can generate action potentials.

A The action potential does not propagate down into the SR. Ca++ is released when the voltage sensitive DHP channels are activated → mechanical opening of the RyR

PH at the arterial end of a capillary is 32 mm Hg, and PH at the venous end is 24 mmHg. The plasma colloid osmotic pressure across the entire capillary bed is 25mm Hg. Across the entire length of the of the capillary, which of the following will most likely occur? A. Net Filtration B. Net Absorption C. Net Filtration and Net Absorption D. Neither filtration nor absorption

A The capillary is losing fluid to the ISF on the arterial side of the capillaries (since Ph > π) and gaining fluid through the venous side (Ph < π). The arteriole side of the capillary is longer than the venous side so across the length of the entire capillary, net filtration is going to occur.

Regarding the human brain (select the MOST CORRECT statement): A. The primary motor cortex is located in the frontal lobe. B. The diencephalon is composed of two structures, the cerebral cortex and the thalamus. C. Sensory information from the skin of the big toe is relayed via ascending spinal tracts to the primary motor cortex D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

A The diencephalon is composed of three structures and they are the thalamus, hypothalamus, and glands. The cerebral cortex is NOT part of the diencephalon. The sensory information from the skin of the big toe will go to the thamalus.

If you are exposed to a muscarinic ACh receptor antagonist, which of the following symptoms would you expect? a. Increase in heart rate b. Decrease in total peripheral resistance. c. Increase in saliva and other digestive enzyme secretions d. (a) and (b) are correct; (c) is incorrect e. (a), (b), and (c) are all correct

A There are no mAChR on the blood vessels so they are not subjected to PSN regulation. The antagonist would block the normal response to ACh so the HR would increase and saliva secretion decreases.

Regarding the neuromuscular junction... A. Depolarization of the presynaptic membrane directly causes voltage-gated calcium channels in the membrane to open. B. Action potentials in the sarcolemma directly cause calcium channels to open. C. Action potentials in the sarcoplasmic reticulum indirectly cause the calcium ATPase pump to function, if ATP is present. D. both a) and b) are correct, and c) is incorrect E. a), b) and c) are all correct

A ....

Which of the following is/are correct about skeletal muscle fibers? (a) [Ca2+] in the fluid of the terminal cisternae is greater than [Ca2+] in the ICF. (b) The motor endplate contains fast voltage-gated Na+ channels and can generate action potentials. (c) During contraction of skeletal muscle fibers, the actin filaments shorten in length. (d) answers (a) and (b) are both correct; answer (c) is incorrect (e) answers (a), (b) and (c) are all correct

A The filaments themselves do not change length. The motor endplate does not have voltage gated channels and they only generate graded potentials.

Select the MOST CORRECT answer. As blood flows from the aorta to capillary beds... A. Total cross-sectional area of the vasculature increases. B. Hydrostatic pressure increases slightly as blood enters arterioles. C. Velocity remains fairly constant. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

A The hydrostatic pressure has to decrease for net absorption to happen since fluids will move from high to low hydrostatic pressure. Since the cross sectional area increases, the velocity will decrease as they are inversly related.

Although many structures are missing, place the following regions of the cardiovascular system in the order that a red blood cell would travel through them, starting at the right atrium A. Right AV Valve B. Right SL Valve C. Pulmonary Artery D. Pulmonary Vein E. Aorta F. Vena Cava

A, B, C, D, E, F

Which of the following are parts of the vertebrate peripheral nervous system? A. Afferent Division B. Efferent Division C. Somatic Nervous System D. Autonomic Nervous System E. Parasympathetic Nervous System F. Sympathetic Nervous System G. Brainstem H. Spinal Cord I. Thalamus

A, B, C, D, E, F

Which part(s) of the brain play a large role in movement coordination? A. Cerebellum B. Frontal Lobe C. Basal Ganglia D. Pons E. Temporal Lobe F. Midbrain

A, B, and C The cerebellum helps coordinate movement in the body such as posture and gait. The frontal lobe contains the primary motor cortex that controls all voluntary movements of the body. The basal ganglia is grey matter deep in the brain that synapses with other cells to control movements.

Which of the following statements about GnRH are true? Choose all of the correct answers. A. During the luteal phase of the ovarian cycle, estrogen secreted by the corpus luteum provides negative feedback regulation of GnRH secretion B. GnRH stimulates the release of LH and FSH from cells in the posterior pituitary C. Estrogen secreted by follicles always provides negative feedback regulation of GnRH secretion. D. GnRH is a steroid hormone secreted by cells in the hypothalamus. E. Estrogen can increase or decrease the amount of GnRH secretion by the hypothalamus, depending on the amount of estrogen. F. Testosterone secreted by interstitial cells in the testes provides negative feedback regulation of GnRH secretion.

A, E, F The corpus luteum does secrete estrogen even though it mainly secretes progesterone. LH and FSH is released from the anterior pituitary. GnRH is a peptide hormone.

During skeletal muscle contraction, as the muscle shortens, A. the A band does not change size, the H zone decreases, and the distance between M line and Z disk increases. B. the I band, the H zone, and the sarcomere decrease in size. C. the sarcomere decreases in size, the distance between M lines decreases in size, and the amount of actin in the A band decreases. D. both a) and b) are correct, and c) is incorrect E. a), b) and c) are all correct

B

Select the MOST CORRECT answer. A thin slice of tissue is examined using microscopy and several stains that allow the detection of specific proteins. You conclude the tissue is cardiac muscle and NOT skeletal muscle because... A. The surface of cells is covered with sodium channels, including ring-like structures that disappear into the tissue. B. You detect the presence of a sodium-calcium exchange protein on the surface of cells within the tissue. C. You detect the presence of actin, myosin, and calcium ATPase pumps. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

B

Which of the following statements comparing different types of muscle is/are correct? (a) Cardiac and skeletal muscle contain actin and myosin but smooth muscle does not. (b) Skeletal and cardiac muscle contain myofibrils that give these muscle fibers a striped appearance under a light microscope. (c) Cardiac and skeletal muscle fibers can be depolarized by an action potential in a neighboring muscle fiber. (d) answers (a) and (b) are both correct; answer (c) is incorrect (e) answers (a), (b) and (c) are all correct

B

Although steps are missing, which of the following sequence of events has been placed in the correct order, based on our current knowledge of synaptic transmission at the neuromuscular junction and skeletal muscle contraction? A. Voltage-gated calcium channel opens...ligand-gated calcium channel opens... ryanodine calcium channel opens...actin and myosin slide relative to each other B. Acetylcholine diffuses across synaptic cleft...end plate potential changes...depolarization of sarcolemma...ATP binds to myosin C. Troponin binds to calcium...voltage-gated calcium channel closes...ATPase pumps calcium down its concentration gradient...actin binds to myosin D. both a) and b) are correct, and c) is incorrect E. a), b) and c) are all correct

B A is incorrect because there is no ligand gated channel between the DHP (voltage gates Ca++ channel). C is very wrong: ATPase will pump the Ca++ against the concentration gradient, which is why ATP is required. The actin will also not be able to fully bind to myosin if the Ca++ concentration is depleted since the tropomyosin will be blocking the myosin binding site.

How will an increase in ACTH production affect CRH levels in the blood? A. Increased CRH B. Decreased CRH C. Cause no change in CRH

B CRH is released from the hypothalamus to trigger the release of ACTH (which is the tropic hormone) from the anterior pituitary. ACTH and CRH is in a negative feedback system so when ACTH levels are increased, the CRH levels decrease.

Human cerebral spinal fluid (CSF) (select the MOST CORRECT statement): A. CSF is similar in composition to blood plasma, except that it has a higher concentration of serum albumin. B. Glucose is a hydrophilic organic compound that can be found in blood plasma, interstitial fluid, and CSF. C. CSF bathes the brain and spinal cord and circulates through a system of ventricles and canals due to the contractile activity of ependymal cells. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

B CSF has less serum albumin than blood plasma since serum albumin is a protein found in blood. The CSF is in the subarachnoid space rather than the ventricles formed by the ependymal cells.

Select the MOST CORRECT answer. An athlete was attempting to improve their performance through doping, the act of taking illegal drugs to increase red blood cell count. Unfortunately, the athlete experienced a reduction of performance instead. Which of the following best explains this outcome? A. Heart rate and stroke volume were increased and therefore cardiac output was reduced. B. An increase in the viscosity of the blood caused total peripheral resistance to increase, which reduced blood flow. C. A decrease in mean arterial pressure resulted because of the increase in total blood volume. Because the bulk blood flow was equal between both sides of the heart, the stroke volume decreased over time. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

B A is incorrect because an increase in HR and SV would increase CO. C is incorrect because increased total blood volume would lead to increased MAP.

PH at the arterial end of a capillary is 30 mmHg, and PH at the venous end is 15mmHg. The plasma colloid osmotic pressure across the entire capillary bed is 25mm Hg. At the venous end of the of the capillary, which of the following will occur? A. Net Filtration B. Net Absorption C. Net Filtration and Net Absorption D. Neither filtration nor absorption

B At the venous side, since the Ph is less than π, there will be net absorption of fluids. There is a higher due to proteins in the plasma which means there's a high concentration of solutes in the blood (high osmolarity). We know water moves from low to high osmolarity so water will be reabsorbed into the cell.

Select the MOST CORRECT answer. In a cardiac myocyte, changes in the permeability of ions can lead to a change in membrane potential. In... A. A conducting cardiac myocyte, the rapid depolarization is caused by the opening of T-type calcium channels. B. A contractile cardiac myocyte, the rapid depolarization is caused by the opening of L-type calcium channels. C. Both conducting and contracting cardiac myocytes, the influx of sodium and calcium causes the membrane to depolarize and the efflux of potassium causes repolarization. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

B In conducting myocytes, the rapid depolarization is caused by the L type Ca++ channels which are funny channels. The rapid depolarization of the contractile myocardium is caused by the Na+ channels not Ca++.

Which hormone is produced by the testes and is responsible for preventing the development of a uterus and fallopian tubes in male fetuses? A. Wolffian hormone B. anti-Müllerian hormone C. testosterone D. dihydrotestosterone (DHT)

B The testes of the male fetus will secrete AMH which will lead to the regression of the Mullerian duct which normally becomes the female internal reproductive organs.

Which of the following steps of excitation-contraction coupling are different between skeletal muscle and contractile myocardium? A. Formation of cross-bridges between actin and myosin. B. Removal of calcium from cytoplasm/sarcoplasm. C. Stimulus to open DHP receptors. D. Stimulus to open RyR.

B and D Contractile myocardium removes excess Ca++ by actively transporting it back into the SR (same as skeletal muscles) but it also gets rid of it by using a Na+ Ca++ antiporter in the membrane. This pump is powered by secondary active transport of Na+ down it's concentration gradient. The RyR receptors in myocardium is NOT mechanically gated to the DHP receptor like in the skeletal muscles. Rather, the RyR receptor is ligand gated and the ligand is Ca++ molecules. This leads to calcium induced calcium release.

A nicotinic ACh receptor antagonist would have which of the following effects A. Reduce the amount of ACh present in the synapse B. Prevent the muscle from contracting C. Block the generation of action potentials in the motor neuron D. Block the generation of action potentials in the muscle fiber

B and D the nAChR normally binds to ACh but in the presence of an antagonist, the receptor would be blocked. This causes a buildup of ACh in the synapse. The antagonist blocks the receptor activity so without it, APs cannot be generated in the muscle fiber and the muscles will not contract. This will not affect the generation of APs in the motor neurons because the receptor is at the receiving end of the motor neuron AP.

Put the following steps in the initiation of an action potential in a skeletal muscle cell in order. A. Calcium concentration in the cytoplasm increases B. Acetylcholine binds to the nicotinic acetylcholine receptor in the motor end plate C. Ryanodine receptors, mechnically gated calcium channels on the sarcoplasmic membrane, open D. PNa+ increases E. An action potential propigates along the membrane to the T-tubule F. DHP receptors change conformation.

B, D, E, F, C, A

Select the MOST CORRECT answer. A. The relative concentration of sodium ions in the sarcoplasm is higher than extracellular fluid but lower than the intercellular fluid of a motor neuron. B. The relative concentration of sodium ions in the t-tubule is higher than extracellular fluid but lower than the interstitial fluid. C. The relative concentration of sodium ions in the interstitial fluid is higher than the sarcoplasm and higher than the intracellular concentration of the motor neuron. D. both a) and b) are correct, and c) is incorrect E. a), b) and c) are all correct

C

Acetylcholine is released by many types of neurons. Which type does not typically release ACh? A. Somatic motor neurons B. Sympathetic preganglionic neurons C. Sympathetic postganglionic neurons D. Parasympathetic preganglionic neurons E. Parasympathetic postganglionic neurons

C ACh is released by most motor neurons to excite the postsynaptic cell. It is released by the preganglionic cell in both the sympathetic and parasympathetic nervous systems. The target tissues of the parasympathetic nervous system have mAChRs so the parasympathetic postganglionic cells must release ACh. The target tissues of the sympathetic NS have adrenergic receptors that respond to epinephrine and norepinephrine so the sympathetic postganglionic neurons do not typically release ACh.

Which trait arose first during the evolution of animals? A. Central Nervous systems B. Neural cords C. Nervous systems D. Ganglia

C Cnidaria had very simple nets of nerves that formed a primitive nervous system

A human XY embryo has multiple mutations in the SRY gene, such that a functional gene product is not present. At birth, which of the following would be present (select the MOST CORRECT statement): A. Seminal vesicles B. Spermatogonia C. Granulosa cells D. Both a) and b) are correct and c) is incorrect E. a), b) and c) are all correct

C Granulosa cells are part of the follicles that release the egg. A and B are both part of the male anatomy which would not be present in this situtation since the SRY gene is not present and testes would not be produced → no Leydig or Sertoli cells to release testosterone or anti-Mullerian hormone

Regarding the patellar tendon reflex... A. The patellar tendon reflex is initiated by stretch receptors in the quadriceps muscle and results in activation of alpha motor neurons innervating extrafusal muscle fibers of the hamstrings. B. The patellar tendon reflex has one synapse in the spinal cord that activates gamma motor neurons innervating extrafusal muscle fibers of the quadriceps. C. Afferent sensory neurons synapse with motor neurons and interneurons that simultaneously activate a flexor and inhibit an extensor muscle group. D. both a) and b) are correct, and c) is incorrect E. a), b) and c) are all correct

C Patellar tendon reflex is also known as the tendon tap reflex. Choice A is incorrect because the muscles being activated are the quadriceps not the hamstrings. Choice B is incorrect because the α motor neurons are being activated in the extrafusal muscle fibers. The gamma motor neurons are located in the intrafusal fibers of the muscle spindle.

Human sensory systems (select the MOST CORRECT statement): A. Sensory information for both vision and touch is relayed to separate regions of the cerebral cortex, but in both cases relies on ascending spinal tracts to reach the brain. B. The location of a stimulus such as touch is coded by the amplitude of the action potentials in the afferent neuron. C. Baroreceptors in the aortic arch respond to changes in blood pressure that are sensed by mechanoreceptors. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

C The amplitude of the AP only provides information about the intensity of the stimulus. The location is coded by the types of receptive fields activated. Sensory information for vision and touch do go to different regions of the cerebral cortex but vision does not go to the spinal cord first.

Which of the following is NOT TRUE of animals that have open circulatory systems? A. They have lower pressure in their circulatory compartments compared to animals with closed circulatory compartments. B. They are not vertebrates. C. Almost all of them have specialized gas transporting blood cells D. They have a mechanism to pump circulatory fluid.

C They have lower pressure because their hemolymph is not contained in closed vessels. Animals with open circulatory systems are usually small invertebrate animals with most cells in contact with the external environment. They do have hearts to pump their circulatory fluids around. Only insects with closed trachea systems have specialized gas transporting blood cells.

Select the MOST CORRECT answer. An intracellular recording of a cardiac myocyte reveals the change in the membrane potential over time. A. The action potential of a contractile cardiac myocyte is nearly 100 times shorter than a typical action potential of a nerve because of its large refractory period. B. The resting potential of the SA node (pacemaker cell) is nearly at the equilibrium potential of potassium. C. A ventricular contractile cardiac myocyte is depolarized for a period of time that is roughly equivalent to ventricular systole. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

C The contractile myocardium's AP is actually longer than the typical AP of a nerve due to it's long refractory period. The SA node does not have a true resting potential since it is always depolarizing to generate the HR. The contractile myocardium has a resting membrane potential close to that of K+.

Regarding nervous systems (select the MOST CORRECT statement): A. During human embryonic development, the neural plate folds into a tube that becomes the brain, whereas the spinal cord and peripheral nervous system develop from the neural crest. B. In the human brain, the cerebral cortex is confined to the frontal lobe and is not found in the parietal, occipital, or temporal lobes. C. A cerebellum is present in the central nervous systems of both mammals and birds. D. Both a) and b) are correct and c) is incorrect E. a), b) and c) are all correct

C The neural crest only develops into the PNS and the brain stem is developed from the neural tube. The cerebral cortex is made up of the front, temporal, occipital, and parietal lobes.

Which of the following scenarios will result in increased levels of tension in a muscle fiber: A. Lengthening the sarcomere so that few cross-bridges can form. B. Evoking motor neuron action potentials in intervals of 200 msec. C. Recruiting greater numbers of Type I motor units. D. Recruiting Type IIB motor units.

C and D Recruiting any motor units will increase tension. Decreasing the number of crossbridges will decrease tension and evoking motor neuron AP at 200 ms intervals will not lead to summation.

Put the following steps in E-C coupling in order. Start with ATP binds to myosin. A. myosin releases ADP B. Myosin releases inorganic phosphate and the myosin swivels, allowing the actin filament to move toward the M line C. ATP binds to myosin D. myosin affinity for actin decreases, and myosin releases actin E. Myosin breaks ATP into ADP and inorganic phosphate F. The energy from ATP hydrolysis causes the myosin head to rotate to a cocked position and bind weakly to actin

C, D, E, F, B, A

Which of the following structures contain many cell bodies? A. Ascending tracts B. Descending tracts C. Autonomic ganglia D. Sympathetic chain E. Dorsal horn F. Ventral root G. Dorsal root ganglion H. Ventral horn

C, D, E, G, H Tracts do not contain cell bodies because they contain only axons. The ventral and dorsal horns are part of the spinal cord and made up of cell bodies. Ganglia are collections of cell bodies. The ventral root does not have cell bodies because there are no ganglia (unlike the dorsal root)

Put the following steps in the relaxation of a skeletal muscle in order. A. elastic fibers in the sarcomere and muscle connective tissue pull the muscle fibers that lack cross bridges back to their relaxed positions B. when myosin releases actin, it is not able to form cross-bridges again C. Calcium is actively transported into the sarcoplasmic reticulum D. tropomyosin blocks actin-myosin binding sites E. calcium unbinds from troponin F. cytosolic concentration of calcium decreases

C, F, E, D, B, A

Select the MOST CORRECT answer. Closed circulatory systems... A. Have an advantage over open circulatory systems in that they can generate higher pressures. B. Can provide vital substances to organisms with high metabolic rates. C. Are common in insects and exchange gas in coordination with tracheal structures. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

D

Which of the following conditions permits the bipotential gonads to develop into ovaries in a female fetus? A. absence of testosterone B. presence of the SRY gene C. presence of estrogen D. absence of the SRY gene E. presence of testosterone F. absence of estrogen

D

You are treating a patient with high blood pressure. Which of the following treatments is/are likely to decrease your patient's blood pressure? a. Giving your patient a β1 adrenergic receptor antagonist b. Giving your patient a muscarinic ACh receptor agonist c. Giving your patient an alpha adrenergic receptor agonist d. (a) and (b) are correct; (c) is incorrect e. (a), (b), and (c) are all correct

D A ß1 receptor antagonist will block the effect of this receptor. The ß1 receptor normally is involved in increasing HR and contractility. If HR increase is blocked, then the HR slows down and this leads to less blood being pumped into the arteries → decreased BP. The mAChR are involved in the PNS response, and it will lead to a slowing of the HR. An agonist would lead to the slowing of the HR and this indirectly leads to a decrease in the BP. An α receptor agonist will not lead to decreased BP since the α receptors will make the blood vessels contract when in contact with an agonist.

Which of the following is/are necessary for skeletal muscle relaxation? (a) Low [Ca2+] in the sarcoplasm (b) ATP-initiated release of actin-myosin cross-bridges. (c) Active transport of Ca2+ back into the ECF. (d) answers (a) and (b) are both correct; answer (c) is incorrect (e) answers (a), (b) and (c) are all correct

D Active transport of Ca++ back into the ECF is not necessary for skeletal muscle relaxation, just transport back to the SR

Human sensory systems (select the MOST CORRECT statement): A. Action potentials in a sensory neuron carry information about the intensity and duration of a stimulus. B. A given sensory modality (e.g. vision) is coded by the sensory neurons that are activated and the specific location in the brain where the neurons terminate (e.g. visual cortex). C. During brain surgery, a surgeon electrically stimulates the part of the primary somatosensory cortex that receives sensory information from the ear; this would cause the person to perceive simple sounds or tones. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct

D C is incorrect because the patient will perceive the stimuli as a touch if it is at the somatosensory cortex. If the temporal lobe were stimulated instead, the patient would hear sounds.

Regarding the comparison between skeletal, cardiac and smooth muscle... A. Skeletal and Smooth muscle have motor units; Cardiac and Smooth muscle have gap junctions. B. Skeletal, Smooth, and Cardiac Muscle have actin and myosin contractile elements. C. Skeletal and Smooth muscle have electrical synapses; Cardiac and Skeletal muscle have chemical synapses. D. both a) and b) are correct, and c) is incorrect E. a), b) and c) are all correct

D Cardiac muscles have electrical synapses (aka gap junctions) and that is how they are able to propagate a signal throughout the heart. Skeletal muscles do not have electrical synapses. They have chemical synapses where neurotransmitters get released.

Which of the following statements about the action potentials in contractile myocardial cells (cardiac muscle) is INCORRECT? A. Compared to skeletal muscle cells, contractile myocardial cells have a lower (more negative) resting membrane potential. B. Action potentials are propagated between adjacent cardiomyocytes through gap junctions. C. The duration of an action potential in a contractile myocardial cell is greater than the duration of an action potential in a typical neuron. D. During the repolarization phase of a contractile myocardial action potential, the cell is highly permeable to sodium, potassium and calcium.

D During repolarization, the cell is highly permeable to K+ only! Contractile myocardial cells do have an extended plateau phase caused by the increase permeability to Ca++ but this permeability decreases and rapid repolarization occurs when the K+ permeability increases.

Where can you find ganglia? a. In the nervous systems of invertebrates b. In autonomic efferent pathways c. In ascending tracts in vertebrates d. (a) and (b) are correct; (c) is incorrect e. (a), (b), and (c) are all correct

D Ganglia is not in the ascending tracts in vertebrates because the ascending tracts are in the spinal cord and ganglia are only part of the CNS. If it's in the CNS, it's a neuron.

Regarding mammalian nervous systems (select the MOST CORRECT statement): A. The cerebellum is involved with the coordination of body movements. B. Microglia function as immune cells in the central nervous system. C. Grey matter in the spinal cord is associated with myelinated axons. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

D Grey matter are the cell bodies and synapses while white matter make up the myelinated sheaths.

Which of the following will result in summation of twitch contractions in a skeletal muscle motor unit? (a) Stimulating several action potentials in a motor neuron that are spaced 50 ms apart. (b) Stimulating two action potentials in a motor neuron that are spaced 50 ms apart. (c) Increasing the amplitude of a single action potential (d) answers (a) and (b) are both correct; answer (c) is incorrect (e) answers (a), (b) and (c) are all correct

D Summation requires multiple twitches close to each other. Amplitude does not matter

Select the MOST CORRECT answer. During the cardiac cycle... A. Blood flows from the right atrium, through the AV valve, and is pumped by the right ventricle into the pulmonary artery. B. The ventricular diastole occurs at the same time as atrial systole and atrial diastole. C. The second heart sound (S2, or dup) occurs just as the left ventricle reaches its highest pressure, which exceeds aortic pressure. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

D The dup sound occurs after the ventricles relax after ejection. C is describing when the heart reaches ventricular ejection.

Regarding human reproduction (select the MOST CORRECT statement): A. At the time of ovulation, the released ovum has not completed meiosis. B. In the absence of pregnancy, the corpus luteum degenerates and plasma progesterone levels decline. C. Fertilization results in the formation of a zygote, which is a single diploid cell that implants in the uterus. D. Both a) and b) are correct and c) is incorrect E. a), b) and c) are all correct

D The ovum finished meiosis after it has been fertilized. If it is not fertilized, the corpus luteum would disintegrate since the presence of the blastocyte is needed to stimulate the corpus luteum to keep producing progesterone. Fertilization results in the zygote but it will undergo serveral rounds of cell division in the fallopian tube and become the blastocyte before implanting into the fallopian tube.

Which hormone keeps the corpus luteum from disintegrating at the beginning of a pregnancy? A. follicle stimulating hormone (FSH) lutenizing hormone (LH) B. gonadotropin releasing hormone (GnRH) C. progesterone D. human chorionic gonadotropin (hCG) E. estrogen

D hCG stimulates the corpus luteum to keep secreting progesterone so the endometrium does not disintegrate. If it does, a period starts.

Following ATP hydrolysis by myosin, which steps occur during one cross-bridge cycle? A. Myosin is activated; if calcium is present in the sarcoplasm, then myosin binds to actin; inorganic phosphate dissociates from myosin. B. Myosin is activated; if calcium is present in the sarcoplasm, then the conformation of troponin and tropomyosin changes; calcium ATPase pumps calcium into sarcoplasmic reticulum. C. Myosin is activated; if calcium is not present in the sarcoplasm, then ADP and inorganic phosphate dissociate from myosin; troponin and tropomyosin remain bound to actin, covering the myosin binding site. D. both a) and b) are correct, and c) is incorrect E. a), b) and c) are all correct

D C is incorrect because Pi and ADP will remained bounded until the powerstroke can proceeded, which it can't in this case because the Ca++ is not present.

Regarding the human endocrine system (select the MOST CORRECT statement): A. The axons of the neurons that produce corticotropin releasing hormone (CRH) are relatively short compared to the axons of the neurons that produce oxytocin. B. Both corticotropin releasing hormone (CRH) and gonadotropin releasing hormone (GnRH) bind to receptors located on the surface of cells of the anterior pituitary. C. A hypothalamic tumor that overproduced corticotropin releasing hormone (CRH) would lead to high plasma cortisol levels through a positive feedback mechanism. D. Both a) and b) are correct and c) is incorrect E. a), b) and c) are all correct

D The neurons that produce CRH deposits it into the bloodstream but the oxytocin is secreted to the posterior pituitary. The axons are shorter for the CRH because the portal vessels are closer. Both CRH ad GnRH bind to the anterior pituitary in order to stimulate it to release their respective tropin hormones. Highl levels of CRH will lead to high cortisol levels but not due to positive feedback.

Regarding the human spinal cord (select the MOST CORRECT statement): A. The dorsal horns contain visceral (internal organ) and somatic sensory neuron terminals and the cell bodies of interneurons. B. Somatic motor efferents are components of the peripheral nervous system, even though their cell bodies are located in the ventral horn. C. The ventral root ganglia contain the cell bodies of somatic motor neurons. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

D The ventral root does not have ganglion.

Based on skeletal muscle anatomy... A. Skeletal muscle cells are called fibers, have multiple nuclei, and have a cytoplasm called the sarcoplasm. B. The sarcolemma contains voltage-gated sodium channels that are also found in the t-tubules. C. The sarcolemma contains ligand-gated cation channels that bind to two molecules of acetylcholine. D. both a) and b) are correct, and c) is incorrect E. a), b) and c) are all correct

E

Efferent division of the nervous system (human) (select the MOST CORRECT statement): A. Autonomic preganglionic neurons always communicate with postganglionic neurons through the release of acetylcholine. B. Motor neurons that innervate skeletal muscle are always excitatory. C. Sweat glands are innervated by sympathetic neurons only, and are not regulated by parasympathetic neurons. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

E

Organization of central and peripheral nervous systems: a. Afferent sensory information enters the spinal cord via axons in the dorsal roots b. Efferent autonomic motor information is transmitted over preganglionic axons coursing in the ventral roots c. The dorsal horn of the spinal cord is gray matter that receives synaptic input from nerve fibers with cell bodies in dorsal root ganglia d. (a) and (b) are correct; (c) is incorrect e. (a), (b), and (c) are all correct

E

Select the MOST CORRECT answer. Lymph... A. Is derived from fluid that is pushed through small openings in capillary walls by pressure that originates primarily from the contraction of the heart's ventricles. B. Absorbs and transports fats from the intestines. C. Is returned to the cardiovascular system through ducts with one-way valves. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

E

Sympathetic and parasympathetic regulation of the heart (select the MOST CORRECT statement): A. Both the sympathetic and parasympathetic branches of the autonomic nervous system regulate heart rate by releasing neurotransmitters that activate a specific G protein-coupled receptor on the surface of sinoatrial (SA) node cells. B. The in vivo pharmacological inhibition of the muscarinic acetylcholine receptor on SA node cells would lead to an increase in heart rate. C. The pharmacological inhibition of beta-1 receptors on SA node cells and cardiomyocytes would lead to a decrease in mean arterial pressure. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

E Both the ß1 and mACh receptors are GPCRs. If the mAChR is inhibited, the PSNS effect cannot happen so the HR will increase. If the ß1 receptors of the heart are inhibited, the HR will decrease and this would lead to a decrease in MAP.

Select the MOST CORRECT answer. A. The firing frequency of Group 1 muscle spindle afferents is highest during a change of muscle length, and the firing frequency of Group 2 muscle spindle afferents is highest when the muscle is longer. B. Golgi tendon organ afferent firing frequency increases when tension on the muscle increases. C. Muscle spindle reflex is an example of negative feedback; afferent sensory neuron detects stretch and the result is an efferent motor neuron activation that results in contraction. D. both a) and b) are correct, and c) is incorrect E. a), b) and c) are all correct

E Golgi tendon organs sense load and responds to changes in load. When thinking of muscle spindle reflex, think of the experiment of dropping a book on a blindfolded person.

Select the MOST CORRECT answer. If a person's blood pressure is 120 mmHg / 80 mmHg, their pulse is 60 beats/min, and their peripheral resistance is 20 mmHg * min/L, then you also know that... A. Cardiac output is below 4700 mL/min. B. Mean arterial pressure is above 93 mmHg. C. Stroke volume is above 77 mL/min. D. Both a) and b) are correct and c) is incorrect. E. a), b) and c) are all correct.

E PP = SP-DP MAP = 1/3(PP)+DP CO = (1/R) x MAP

As a component of the overall response to stress, epinephrine is released from cells of the adrenal cortex into the interstitial compartment where it acts on neighboring cells. A. True B. False

False Epinephrine is released by the adrenal medulla no the adrenal cortex. The adrenal cortex releases cortisol.

Because the neurotransmitters released on neuromuscular junction synapses are variable, both depolarizing and hyperpolarizing graded potentials can occur at the motor end plate of the muscle fiber. A. True B. False

False Only depolarizing graded potentials can occur at the motor endplate of muscle fibers. The graded potentials created by muscle fibers always depolarize and always reaches threshold to form an AP further down the sarcolemma.

Oxytocin and vasopressin are two peptide hormones that are synthesized and released by the posterior pituitary. A. True B. False

False Oxytocin and vasopressin are hormones synthesized and released by the posterior pituitary. However, while oxytocin is a peptide hormone, vasopressin is a steroid hormone.

The blood brain barrier is formed by the processes of myelinating oligodentrocytes, and prevents the movement of many hydrophilic molecules from the circulation into the brain. A. True B. False

False The BBB is formed by astrocytes that wrap around the capillaries. The oligodendrocytes from the myelin sheath of axons in the CNS.

Throughout the vascular tree, arteries carry oxygenated blood whereas veins carry deoxygenated blood. A. True B. False

False The pulmonary arteries carry deoxygenated blood from the right ventricle to the lungs. Arteries → Away from heart Veins → Back to the heart

A type IIB motor unit could contain both Fast Oxidative and Fast Glycolytic muscle fibers, but not Slow Oxidative muscle fibers. A. True B. False

False Type IIB motor unit only contains fast twitch glycolytic muscle fibers. Type IIA motor units have fast oxidative muscles.

Cortisol and ________________ are both hormones that bind to receptors found on/in liver cells, and both promote gluconeogenesis and increases in blood glucose concentration.

Glucagon Low BG will stimulate the release of glucagon which will increase the BG levels

If the dorsal root ganglia from a given spinal segment were removed, sensory information from the associated parts of the body could not be conveyed to the CNS. A. True B. False

True Afferent neurons synapse at the dorsal root ganglia before it reaches the spinal cord

A deoxygenated red blood cell returning to the heart from the systemic circulation would pass through the right ventricle before passing through the left atrium. A. True B. False

True Blood from systemic circulation returns to the heart through the vena cava. It then enters the right atrium → right ventricles → pulmonary arteries → lungs → pulmonary veins → right atrium → and finally to the right ventricle.

Temporal summation and recruitment are used simultaneously by the central nervous system to increase the strength of contraction of a skeletal muscle. A. True B. False

True Both can happen simultaneously, but recruitment must happen before summation.

If an XX fetus is exposed to DHT early in development, at birth the child will have a uterus, and the external genitalia may be masculinized. A. True B. False

True XX means there is no Y chromosome and the SRY gene is not present. Without the SRY gene, the testes will not develop, therefore the ovaries will form. The development of the external genitalia is controlled by the presence of androgens. DHT is an androgen and since it is present, male external genitalia will develop.

If an individual suffered damage to the brainstem, they would likely experience difficulty controlling their breathing, blood pressure and eye movements. A. True B. False

True The brainstem controls involuntary function.

What is the name of the uterine tissue layer that changes in thickness during the menstrual cycle, and into which a fertilized embryo implants at the start of pregnancy?

endometrium

Which lobe of the cerebrum contains the primary motor cortex and is the most anterior lobe?

frontal Anterior means towards the front of the body.

A single motoneuron and all of the muscle fibers it innervates is called a......

motor unit