Practice Exam #1 (Fall 2011)

Using a #2 pencil, place the following information on your SCANTRON: 1. NAME A. Print your complete name in the space indicated at the top of the scantron. B. Print your last name in the boxes in the upper left hand corner (LAST NAME FIRST) C. DARKEN the corresponding letter spaces in the alphabet matrix below the boxes. 2. STUDENT ID NUMBER A. Place your 8-DIGIT STUDENT ID number in the boxes at the bottom left portion of the scantron labeled IDENTIFICATION NUMBER (beginning with the box on the left) B. DARKEN the corresponding numbers in the number matrix below the boxes. 3. Sign your scantron sheet. AT THE END OF THE EXAM THE SCANTRON SHEET MUST BE HANDED IN. NOTE: The exam question packet is 2-sided. THE FOLLOWING CONDITIONS WILL APPLY TO ALL EXAM QUESTIONS: 1. For each numbered question, SELECT THE ONE BEST ANSWER 2. All questions refer to conditions in a healthy individual at rest, unless otherwise stated in the question. 3. For all questions of the general form: If X is increased (or decreased), then Y will: A. increase B. undergo little or no change C. decrease ASSUME: i. That the increase or decrease in X is relative to the normal resting state value of X, unless otherwise stated in the question. That all other factors that may affect the response of Y remain constant except for X, unless otherwise stated in the question. Exam 1 Physiology 201 10/3/11 The exam has 12 pages and 46 questions 13 Which of the following statements about sleep is TRUE? Adequate sleep is important to immune function before exposure to an immunogen like influenza virus, but not after exposure has occurred. REM sleep is definitely required for all types of learning. For some types of learning, a nap with REM sleep can provide equivalent improvement on an assessment of learning as can a full night?s sleep. Lack of sleep has an insignificant effect on the ability to perform surgical tasks Homeostasis involves processes that Maintain the composition of the interstitial fluid. Ensure the relative constancy of the intracellular fluid Regulate the conditions of the interstitial fluid and plasma to maintain relative constancy. Increase variability within the internal environment. Which of the following accurately describes an afferent pathway within a homeostatic reflex arc? Communication through nerves from the integrating center to the effector. Communication through nerves from the receptor to the integrating center. The central nervous system (CNS) A change in muscle activity Return of the variable back toward its starting value (setpoint) Athletes training for the Olympics will frequently train at high altitude. Initially, they suffer from altitude sickness due to the low oxygen (O2) in the air leading to reduced total O2 content of the blood. The immediate response to this is increased ventilation, which leads to some improvement, but after several days at high altitude additional changes occur that increase total O2 content more significantly toward normal despite the low O2 in the air. This process is termed Acclimatization Resetting the set point Feedforward regulation Positive feedback Given a cell that has an extracellular concentration of X- = 5 mM and an intracellular concentration of X- = 150 mM, which of the following statements about this cell is/are TRUE? The membrane has active transporters that pump X- into the cell EX = a negative number If the cell has leak channels for only X-, the resting Vm = EX a and c a, b and c If the equilibrium potential of Z- (EZ ) = -65mV, then the extracellular fluid (ECF) concentration of Z- is __________ the intracellular fluid (ICF) concentration. The cell has a resting Vm = -70 mV, so if Z- channels were opened on the membrane, then net _______ of Z- would occur and the membrane potential would ________. Less than, influx, hyperpolarize Greater than, influx, hyperpolarize Less than, efflux, depolarize Greater than, efflux, depolarize Greater than, influx, depolarize Hyperkalemia is a condition in which a patient has higher than normal blood K+ concentrations, and is usually associated with loss of kidney function. Hyperkalemia would cause the resting Vm to become _______ compared to normal. depolarized hyperpolarized unchanged For a neuron with EK = -90mV, ENa = +60 mV and ECl = -80 mV, a drug is applied that alters the membrane potential from -70mV to -80 mV. Which of the following could NOT be a mechanism of action for this drug? The drug may have Blocked leak Na+ channels in the membrane Opened ligand-gated K+ channels in the membrane Blocked leak Cl- channels in the membrane All of the above (meaning none of them are possible mechanisms) Which of the following is FALSE about ion channels? The opening of a ligand-gated channel is regulated by binding of a molecule to the intracellular or extracellular region of the protein The opening of voltage-gated channels is caused by the channel changing shape when the membrane potential is a certain value Leak channels are only open in a resting membrane and close if the membrane is depolarized or hyperpolarized. Current flow through leak channels generates the resting membrane potential. You accidentally bump your elbow and get that strange, tingly sensation that occurs from ?hitting your funny bone.? In fact, you have struck the middle of the ulnar nerve and initiated action potentials in the middle of sensory and motor axons running through that nerve. In this scenario, which of the following is/are TRUE? Action potentials will propagate only toward the hand in the motor neurons and only toward the spinal cord in the sensory neurons. Because the sensory afferents originate in the region of the little finger, activation at the middle of the neurons results in a tingly sensation in the area of the little fingers even though the hand was not struck. Action potentials will propagate in both directions from the activated region in both the sensory and motor neurons. a and b b and c Which of the following statements about action potentials is/are TRUE? V-gated K+ channels open at the peak of the AP and are all closed when the membrane reaches -70 mV. The stimulus that opens the V-gated Na+ channels is binding of neurotransmitter and the stimulus that opens the V-gated K+ channels is depolarization to threshold. Depolarization is mediated by V-gated Na+ channels that close at the peak of depolarization of the AP. During the hyperpolarization phase, the membrane is in the relative refractory period. All of the above Graded potentials? are always depolarizing under normal conditions. Decrease in amplitude with distance from the initial location. in a given cell always have the same amplitude. have a refractory period. The drug Goblue partially blocks Na+ leak channels on neurons. Exposure of a neuron to Goblue will Block the generation of APs completely Increase the likelihood of APs occurring Decrease the likelihood of APs occurring Depolarize the membrane toward threshold b and d A man has neurons that express 2x more V-gated K+ channels in their axon membranes than do normal neurons. As a result of his disorder, his neurons? maximum AP frequency will be ______ and their AP propagation rate will be _____ compared to normal. Unchanged, decreased Unchanged, increased Decreased, unchanged Increased, increased Increased, unchanged Which statement is/are TRUE about chemical synapses? Arrival of an AP at the presynaptic axon terminal always generates an EPSP in the postsynaptic neuron. The propagation of signal through a chemical synapse is unidirectional from pre- to post-synaptic cell. The release of neurotransmitter from a presynaptic axon terminal requires Ca2+ influx b and c a, b and c Action potentials arriving at the axon terminal of a presynaptic neuron Always lead to generation of action potentials in the postsynaptic neuron. Always cause ligand-gated Na+ channels to open on the postsynaptic neuron and depolarize the cell membrane. Can directly activate voltage-gated Na+ channels in the postsynaptic neuron. Always activate voltage-gated calcium channels in the presynaptic terminal membrane. Neurotransmitter A generates EPSPs in neuron B. In the presence of a drug that increases the activity of the enzyme that degrades neurotransmitter A, you would observe An increase in EPSP amplitude in neuron B An increase in AP amplitude in neuron B A decrease in EPSP amplitude in neuron B An increase in frequency of APs in neuron A A decrease in AP amplitude in neuron B Afferent neurons carrying information from the periphery to the CNS Enter the spinal cord via the ventral root Have cell bodies located at the peripheral end of the neuron Will transmit information via ascending tracts to the cerebral cortex on the opposite side of the body Sometimes have individual long axons that go all the way from the periphery to the cortex without synapsing until the cortex Which of the following is the most complex integrating area of the nervous system? Thalamus Cerebrum Cerebellum Medulla oblongata Brainstem Which of the following statements about the nervous system is TRUE? Afferent and efferent neurons of the peripheral nervous system typically have their cell bodies within the CNS. Most nerves carry both afferent and efferent information. The hypothalamus, which is heavily involved in homeostatic mechanisms, is part of the brainstem. Parasympathetic autonomic nerves tend to come from the middle portion of the spinal cord (T1-L2) while the sympathetic autonomic nerves tend to come from the top and bottom (above C1, and below S1). Which of the following characteristics do both the somatic motor and the parasympathetic branch of the autonomic nervous system have in common? Acetylcholine is the neurotransmitter at the target tissue Target tissues are under ?voluntary? control The pre-and post-ganglionic neurons synapse closer to the target tissue than to the CNS. They are responsible for the ?fight or flight? response. All of the above Which of the following statements about human sensory systems is FALSE? Sensory receptors can transduce non-electrical stimuli such as heat or sound to electrical signals (graded or action potentials) Information about the location of the stimulus is relayed based on the location of the receptor AP frequency in the sensory neuron is determined by stimulus strength Each receptor type can only respond to one type of stimulus (light, sound, etc). Which of the following is TRUE? Nocturnal animals have a dark choroid that absorbs light The majority of refraction occurs at the cornea Photoreceptors are located in the sclera The ciliary muscles and the iris are skeletal muscles Janine has never worn glasses, but lately she notices that when she reads she has to hold the book farther from her face in order to see the text clearly. She realizes she probably needs to get ?reading glasses? now. The lens in Janine?s eye has a decreased ability to undergo the process of ________ to see near objects. Divergence Refraction Accommodation Acclimatization For Janine in #24, above, the focal point of near objects is now focused _____ the retina and so she will need a _________ lens in order to move the focal point onto her retina. Behind, convex Behind, concave In front of, convex In front of, concave The rods and cones contain opsins that convert GTP into cGMP generate graded hyperpolarizations after light strikes the chromophore retinal demonstrate increased transmitter release in response to absorption of light demonstrate a decrease in AP frequency when light strikes the chromophore retinal all of the above The retina Has a blind spot if light focuses at the fovea when only one eye is used Contains only two cell types: rods and cones Has a region termed the optic disk where the ganglion cell axons leave the eye as the optic nerve Has 3 different types of cones differentiated by the type of G protein they express. Cortisol, a steroid hormone, Travels through the blood to its target tissues Can cross the membrane of the target cell and interact with a receptor inside the cell Will generate rapid responses from the target cell and its effects will be short-lived (ie. minutes rather than hours-days) a and b a and c Which of the following statements is TRUE about hormones: Lipid soluble hormones are protected by binding proteins in the blood, resulting in a decreased rate of degradation Lipid soluble hormones are stored in vesicles so they cannot diffuse from the cell unless there is a signal to cause exocytosis Catecholamines like dopamine travel freely in the blood and degrade over weeks The peptide hormone insulin has its receptor in the cytosol of its target cell Which of the following is TRUE regarding the hypothalamus and pituitary gland? The anterior pituitary is composed of neuron axons that originate in the hypothalamus Neurons from the hypothalamus synapse on anterior pituitary cells to control hormone release Oxytocin and Vasopressin (ADH) are released from the posterior pituitary directly into the hypothalamo-pituitary portal vessels Anterior pituitary hormones like ACTH are released into the systemic circulation and travel to the rest of the body Thyroid hormone release is regulated in the same fashion as cortisol release: TRH from the hypothalamus regulates release of TSH from the anterior pituitary, which regulates release of thyroid hormone from the thyroid gland, which has feedback at the anterior pituitary and hypothalamus. If an individual has an underactive thyroid gland and is producing lower than normal thyroid hormone, her levels of TRH would be ____ and of TSH would be _______ compared to normal. Increased, increased Increased, decreased Decreased, increased Decreased, decreased Unchanged, increased ATP is directly required for which of the following events. Release of Ca2+ ions from the sarcoplasmic reticulum Detachment of myosin head from actin Rotation of tropomyosin exposing myosin binding sites All of the above According to the sliding filament model, when a muscle fiber contracts and shortens which of the following decreases in length? I-band H-zone Thick and thin filament length a and b a, b and c The thin filament is composed of Troponin, actin and tropomyosin Troponin, actin and myosin Myosin heavy and light chains Actin, tropomyosin and myosin The direct cause of rigor mortis after death is that The enzyme on myosin is not functioning and ATP hydrolysis cannot occur Cross-bridges cannot detach from actin Build up of Pi in the cytosol decreases the number of cross-bridges undergoing the power stroke The myosin binding site on actin is altered so that it will not release the myosin head Which of the following is/are TRUE? Action potential propagation along the membrane directly causes Ca2+ release from the T-tubules End Plate Potentials (EPPs) are usually depolarizing, but may sometimes be inhibitory When action potentials reach the motor neuron axon terminal, they cause release of norepinephrine onto the motor end plate An action potential in a motor neuron always generates an action potential in the muscle fiber membrane under normal conditions Muscle fiber fatigue Refers to decreased force production in a fiber due to repeated activation Only occurs during high intensity activity Low intensity, long duration activity produces fatigue from which the fiber recovers quickly in a matter of minutes. Occurs because the SR begins to run out of Ca2+ to release A chin-up involves two steps; you start with your hands grasping a bar that is above your head, then you 1) lift so that the chin is level to your hands and above the bar and then 2) hold your body in that position for ten seconds. Which of the following best describes the muscle contractions involved in these two steps? Step 1: lengthening (eccentric) contraction, Step 2: isometric contraction Step 1: isometric followed by isotonic concentric contraction, Step 2: isometric contraction Step 1: isotonic concentric contraction, Step 2: isometric followed by lengthening (eccentric) contraction Step 1: isotonic concentric contraction, Step 2: isometric contraction Step 1: isometric contraction, Step 2: lengthening (eccentric) contraction Which of the following describes the relationship between load and single fiber contraction velocity? As load increases, isotonic contraction increases and thus velocity remains unchanged Increasing the velocity of contraction allows heavier loads to be lifted Distance shortened/time decreases as load increases. As load increases, more Ca2+ is released from the SR, leading to an increase in velocity of contraction As load increases beyond the maximum isometric tension, isotonic shortening velocity increases As action potential frequency increases, eventually a muscle fiber will reach a state of sustained contraction at maximum tension. This state is Caused by sustained elevation of Ca2+ in the cytosol due to slowing of the Ca2+ ATPase caused by high AP frequency Caused by increased opening of RyR and high Ca2+ release outpacing the rate of Ca2+ ATPase activity. Caused by decreased ATP levels with high AP frequency b and c a and c Maximum isometric tetanic tension is highest at a range of lengths termed Lo. Which of the following is TRUE about the muscle fiber? At Lo, the thick filaments and thin filaments are at optimal overlap At Lo, the thick and thin filaments are at minimum overlap If the muscle fiber length is longer than Lo, it can generate increased tension due to increased contraction length of the actin and myosin filaments At lengths shorter than Lo, overlap of thin filaments increases actin/myosin binding, leading to increased maximum tension ATP production in a skeletal muscle fiber: At the start of activity can be produced for about 1 minute by conversion of creatine phosphate +ADP into ATP + creatine. Occurs by primarily by oxidative phosphorylation as long as oxygen supply is not limited Occurs by glycolysis for high intensity activity (near maximum) lasting for up to 15 minutes. Utilizes fatty acids as a substrate for glycolysis, as well as glucose and glycogen. Skeletal muscle fibers Can have a slow or fast myosin molecule Fatigue more slowly if they utilize primarily oxidative phosphorylation and faster if they utilize primarily glycolysis to produce ATP. Oxidative fibers have many more mitochondria than glycolytic fibers a and b a, b and c Whole muscle tension Is determined by the number of active muscle fibers Is determined by the AP frequency in individual muscle fibers Is generated by recruiting large fibers first followed by intermediate and then small fibers. a and b a, b and c Training can cause an increase in force development in skeletal muscle due to Increased numbers of muscle fibers within the muscle Increased size of the muscle fibers already within the muscle Increased size of only the glycolytic fibers Increased rate of Ca2+ ATPase activity Strength training with short duration, high intensity exercise will lead to Increased glycolytic capacity in fast muscle fibers Increased myoglobin content in the muscle Increased oxidative capacity in the fast muscle fibers Decreased numbers of slow oxidative fibers C C B A D revised at end to accept c or d?a not really accurate, but ?d. a and c? was my intended answer and most students got it right. C along could have been considered correct. D A C C E D B C E D D C C B B A D B C A B C D A D A B D A B D A B C B A B E D B A