1Physiology What allows for the voluntary retention of urine once a full bladder has induced an increase in bladder parasympathetic tone? A. Inhibition of S2–S4 α-motor neurons causing relaxation of the external urethral sphincter striated muscle fibers B. Inhibition of pelvic splanchnic nerves causing a compensatory increase in bladder sympathetic activity C. Activation of S2–S4 a-motor neurons causing contraction of the external urethral sphincter striated muscle fibers D. Activation of neurons in the inferior mesenteric ganglion and subsequent contraction of the internal urethral sphincter E. Activation of neurons in the inferior mesenteric ganglion and subsequent contraction of the external urethral sphincter What neurotransmitter is used by preganglionic sympathetic fibers? A. Norepinephrine B. Epinephrine C. Glutamate D. Acetylcholine E. GABA Use the following answers for questions 3 and 4: A. Botulism toxin B. Tetanus toxin C. Diphtheria toxin D. Alpha bungarotoxin E. Tetrodotoxin This toxin inhibits vesicle fusion in the presynaptic terminal at the neuromuscular junction. This toxin inhibits RNA translation. What decreases the rate of degradation of a passively conducted electrical signal in an axon? A. Decreasing axonal diameter B. Demyelinating an axon C. Increasing axonal membrane resistance D. Increasing extracellular resistance What substance releases factor VIII from von Willebrand factor? A. Fibrinogen B. Platelets C. Factor IX D. Antithrombin III E. Thrombin In brain death, what happens to the intracranial pressure (ICP) as the mean arterial pressure (MAP) rises? A. Cerebral autoregulation increases ICP. B. Cerebral autoregulation decreases ICP. C. The lack of cerebral autoregulation causes an increase in ICP. D. The lack of cerebral autoregulation causes a decrease in ICP. E. Cerebral autoregulation maintains a relatively constant ICP. The sensory nerves originating in the extremities with cell bodies in the dorsal root ganglia are examples of what classification of neuron? A. Unipolar B. Bipolar C. Multipolar D. Pyramidal E. Multiaxonic To what type of motion/activity will the utricle respond? A. Injecting cold water into the ear of a person sitting upright B. Sleeping C. Stopping at a stop sign in a motor vehicle D. Beginning to spin in an office chair E. Falling at terminal velocity while skydiving A patient has a hormone-producing pituitary microadenoma that puts him at risk (if left untreated) for peripheral neuropathies, cardiac arrhythmias, and sleep apnea. What hormone is the adenoma producing? A. Adrenocorticotropic hormone (ACTH) B. Growth hormone C. Prolactin D. Thyroid-stimulating hormone E. Follicle-stimulating hormone What are the major proinflammatory cytokines? A. TGF- α and VEGF B. IL-1 and TNF-α C. IL-6 and TGF-α D. IL-6 and IL-13 E. IFN-γ and IL-10 What is a miniature end-plate potential? A. Inhibitory postsynaptic potential B. Excitatory postsynaptic potential C. Response of the postsynaptic terminal caused by the release of a single vesicle into the synaptic cleft D. Response of the postsynaptic terminal caused by the release of a single molecule of neurotransmitter into the synaptic cleft E. Response of the postsynaptic terminal caused by the release of the neurotransmitters from a single neuron only When do T-type calcium channels open during the action potential? A. At the resting potential B. Between the resting and threshold potentials C. Between the threshold potential and maximal depolarization D. Between maximal depolarization and the resting potential E. Between the resting potential and “overshoot” phase (hyperpolarization) How do class 3 cardiac antiarrhythmics (potassium channel blockers) affect action potentials and conduction velocity? A. Shorten action potential refractory period and increase conduction velocity B. Shorten action potential duration and maintain normal conduction velocity C. Prolong action potential refractory period and slow conduction velocity D. Prolong action potential duration and maintain normal conduction velocity E. Shorten action potential refractory period and slow conduction velocity What neurotransmitters never can be used to upregulate action downstream in a neural network? A. GABA and glycine B. Glutamate and acetylcholine C. Norepinephrine and epinephrine D. Dopamine and substance P E. All neurotransmitters can be used to upregulate downstream neural network activation How does caffeine exert its effects? A. GABA receptor antagonism B. Phosphodiesterase inhibition C. Adenosine receptor agonism D. Acetylcholinesterase activation E. Ryanodine receptor antagonist How does cocaine affect neurotransmission at the synaptic cleft? A. Inhibition of the presynaptic uptake of monoamines B. Induction of the release of monoamines C. Prevention of the degradation of monoamines in the synaptic cleft D. Blockade of the postsynaptic uptake of monoamines E. Induction of the postsynaptic uptake of monoamines What are the degradation products of the reaction between acetylcholine and acetylcholinesterase on the postsynaptic membrane? A. Phosphatidylcholine and choline B. Phosphatidylcholine and acetate C. Acetyl CoA and acetate D. Choline and acetate E. Choline and acetyl CoA What role do caspases play in necrosis? A. Caspases signal and regulate the orderly fragmentation of DNA. B. Caspases signal a cell to undergo necrosis. C. Caspases typically are not part of necrosis. D. Caspases inhibit necrosis and cell death. What molecules are needed to activate the ligand-gated component of NMDA receptors? A. Glutamate and glycine B. Magnesium and glycine C. Magnesium and serine D. Aspartate and zinc E. Zinc and glycine What is the mechanism of action of bisphosphonates? A. Increasing the body stores of calcium B. Activation of osteocytes C. Inhibition of osteocytes D. Inhibition of osteoclasts E. Recruitment of osteoblasts Where does GABA bind on the GABAA receptor? A. On the α subunit B. On the β subunit C. Between the α and β subunits D. On the γ subunit E. Between the α and γ subunits A patient with a complete spinal cord injury has a patellar reflex in the acute period following his injury. What circuitry component must be intact? A. Cell bodies in the midthoracic spinal cord B. Dorsal columns between the brain and lumbar spinal cord C. Cell bodies in the lumbar prominence of the spinal cord D. Anterior horn cells between the brain and lumbar spinal cord What is the mechanism of action for temozolomide (Temodar)? A. Microtubule inhibitor B. DNA cross-linking
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