PSL 431 Practice Questions Exam 2

4. Pick the answer from the list below that best matches each description. Each answer is used once. ANSWERS Dorsal column system Muscle spindle Golgi tendon organ Lateral inhibition Somatotopic organization DESCRIPTION A. Sensory afferents from each part of the body surface project to different parts of the somatosensory cortex. B. Enhances two-point discrimination C. Carries sensory information regarding touch, light pressure, muscle length and tension, and limb position D. Sensory receptor for muscle force E. Sensory receptor for muscle length

A. Somatotopic organization B. Lateral inhibition C. Dorsal column system D. Golgi Tendon organ E. Muscle spindle

2. Name at least three of the chemicals in the "toxic soup of inflammation" (chemicals released during inflammatory processes that sensitize nociceptors).

Bradykinin, serotonin, substance P, and potassium ion.

15. When applied to the skin of a subject's forearm, Drug Q causes the skin blood vessels to constrict and the pilomotor muscles to contract (goose bumps form). The drug does not affect sweating rate. Drug Q could be: A. a cholinergic agonist B. muscarine C. an adrenergic agonist D. A and B are correct E. A, B, and C are correct

C An adrenergic agonist would cause skin blood vessels to constrict and pilomotor muscles to contract. The sweat glands of the forearms do not have adrenergic receptors, so an adrenergic agonist would have no effect on sweating rate. Choices A and B are wrong, because a cholinergic agonist (of which muscarine is an example) would dilate skin blood vessels, have no effect on pilomotor muscles, and increase sweating.

1. For each of the following neuronal type, state whether it is part of the peripheral nervous system (PNS) or the central nervous system (CNS). For each neuronal type that is in the CNS, state whether it is in the brain or the spinal cord. Pyramidal pathway neurons Alpha motor neuron Gamma motor neuron

Pyramidal pathway neurons (CNS, brain) Alpha motor neuron (CNS, spinal cord) Gamma motor neuron (CNS, spinal cord)

Which is a CORRECT match of a fluid and its function within the auditory system? a. Vibrations of the Scala Tympani mediate sound dissipation b. The Scala Vestibuli has a higher concentration of K+ than the ICF c. The ossicles are contained with a fluid filled pouch d. The Scala Media is filled with Perilymph e. The Hair Cells are immersed in the same fluid as the Scala Tympani

a. Vibrations of the Scala Tympani mediate sound dissipation

The Optic Chiasm is: a. Where axons from the nasal retina of each eye cross to other side of brain b. Where axons from the temporal retina of each eye cross to other side of brain c. Located within each eye d. The same thing as the Optic Tract e. Part of the Visual Cortex

a. Where axons from the nasal retina of each eye cross to other side of brain

The Hair Cells that enable hearing are located within: a. The stapes b. The organ of corti c. The scala vestibuli d. The perilymph e. The eustachian tube

b. The organ of corti

Photopigments in rods and cones are similar in all of the following ways EXCEPT for: a. They all contain retinal b. They all contain the same opsin c. They are all contained within discs in the outer segment d. They are required for light sensing e. They act as GPCRs

b. They all contain the same opsin

Which of the following is matched with the type of blindness it would cause? a. Loss of M-Opsin will cause night blindness b. Mutation of S-Opsin causes red-green color blindness c. Lesion of visual cortex will cause loss of ability to detect shape, color and location d. Lesion of the Optic Chiasm will cause total blindness e. Mutation of L-Opsin will cause Deuteranopia

c. Lesion of visual cortex will cause loss of ability to detect shape, color and location

Identify the TRUE statement about components of the visual system: a. Rods enable high acuity vision b. Transducin is the molecule that absorbs light in photoreceptors c. The axons of ganglion cells form the optic nerve d. Information from the left eye is only processed in Visual Cortex on the left side of the brain e. Bipolar Cells fire action potentials to convey visual stimuli

c. The axons of ganglion cells form the optic nerve

Which of the following might result in Sensorineural Deafness? a. Having a cork plugging up your eardrum b. Swimmers Ear (getting water trapped in your middle ear) c. Years of being a roadie for the loudest band in the world d. Failing to ever clean the earwax from your ears e. A small puncture of the tympanic membrane

c. Years of being a roadie for the loudest band in the world

Why is vision sharpest at the fovea? a. It is the part of the retina with the most Rods b. It is the part of the retina that has the most Ganglion Cells c. It is where the optic nerve exits the eye d. It is where there are no Bipolar and Ganglion Cells to block the light path e. It is the part of the retina with the fewest Cones

d. It is where there are no Bipolar and Ganglion Cells to block the light path

All of the following are steps of the Auditory Pathway EXCEPT for: a. Hair Cells are the receptor cells b. Spiral Ganglion cells convey sound information to the brain via Auditory Nerve c. Axons conveying sound information cross within the brainstem d. Sound information is processed in the Lateral Geniculate Nucleus of the Thalamus e. Sound information is ultimately received and processed in Primary Auditory Cortex

d. Sound information is processed in the Lateral Geniculate Nucleus of the Thalamus

Which of the following is TRUE about how the Basilar Membrane (BM) enables hearing? a. Sound waves detected at the base of the BM specifically convey louder sounds b. Sound waves detected near the helicotrema specifically convey louder sounds c. Sound waves detected near the Oval Window specifically convey low pitch sounds d. Sound waves detected near the helicotrema specifically convey low pitch sounds e. All hair hells detect high pitch sounds

d. Sound waves detected near the helicotrema specifically convey low pitch sounds

Which is the TRUE statement about phototransduction? a. A conformational change in Opsin directly opens mechanically-gated K +channels to hyperpolarize the photoreceptor b. It relies on the heterotrimeric G-Protein cGMP Phosphodiesterase c. Light converts all trans-retinal to all cis-retinal d. Light causes graded depolarization of the photoreceptor e. Degradation of cGMP leads to a decreased Na +movement into the photoreceptor

e. Degradation of cGMP leads to a decreased Na +movement into the photoreceptor

11. Which of the following neurotransmitters directly inhibits the release of substance P (SP) from the nerve terminal of sensory neurons and attenuates pain sensation? a. Bradykinin b. Acetylcholine c. Prostaglandins d. Substance P e. Natural opioids (such as encephalin)

e. Natural opioids (such as encephalin)

9. Which of the following always has an excitatory effect on their target tissues? A. somatic motor neurons B. parasympathetic motor neurons C. sympathetic motor neurons D. A and B are correct E. A, B, and C are correct

A Action potentials in somatic motor neurons always stimulate skeletal muscle to contract; even a single action potential in an alpha motor neuron is normally sufficient to initiate a contraction in the skeletal muscle fibers that it innervates. By contrast, sympathetic and parasympathetic motor neurons sometimes increase the activity of their target tissues and sometimes decrease it . . . depending on the particular neurotransmitter released from the neuron and the particular type of receptor present on the target tissue.

10. If a patient were given a drug that blocked the effects of the parasympathetic nerves on the heart, the autonomic nervous system : A. could still raise heart rate above its intrinsic level B. could still lower heart rate below its intrinsic level C. could still raise and lower heart rate from its intrinsic level D. could neither raise nor lower heart rate from its intrinsic level

A By activating the sympathetic nerves to his heart, the patient could still increase heart rate above its intrinsic level. However, with parasympathetic effects blocked, there would be no way for the patient to decrease heart rate below its intrinsic level.

8. Norepinephrine increases smooth muscle contraction in: A. blood vessels B. bladder muscle C. the respiratory airways D. the sweat glands E. All of the above are correct.

A Norepinephrine increases the contraction of the smooth muscle in the walls of all blood vessels, and causes the vessels to constrict (alpha adrenergic effect). Norepinephrine relaxes the smooth muscle in the wall of the bladder and relaxes the bronchial smooth muscle in the respiratory airways (beta-2 adrenergic effect). This question illustrates that the effect of norepinephrine on smooth muscle depends on the specific type of adrenergic receptor present in the smooth muscle of the particular organ. Answer D is nonsense, because the sweat glands don't have any smooth muscle.

6. Two of the following comparisons between the somatic nervous system and the autonomic nervous system are TRUE. The others are FALSE. Which two comparisons are TRUE? Why is each of the others FALSE? Somatic Nervous System Autonomic Nervous System A. Target tissue is muscle. Target tissue is glands. B. Motor neuron action potentials Motor neuron action potentials always excite target tissue always inhibit target tissues C. Neurotransmitter at target tissues is Neurotransmitter at target tissues is Acetylcholine norepinephrine.

A is TRUE. B is FALSE, because motor neurons (i.e. VEN) can either activate or inactivate the target tissue. C is partially TRUE, because the neurotransmitter released from the nerve terminals of the motor neurons can be either acetylcholine or norepinephrine.

2. Pick the answer from the list below that best describes the location of the cell body of each neuron. Each answer is used once. ANSWERS Dorsal root ganglion Sacral spinal cord Thoracic spinal cord Ventral horn of the cervical spinal cord Primary motor cortex Thalamus Brainstem NEURONS A. Somatic afferent neuron (SAN) from nociceptors in skin of the foot. B. motor neuron (SEN) to the biceps muscle of the arm. C. Neurons delivering sensory information to the somatosensory cortex from nociceptors in the skin of the foot.

A. Dorsal root ganglion B. Ventral horn of cervical spinal cord C. Thalamus

1. You won't find any autonomic neurons coming out of the _________ level of the spinal cord. A. cervical B. thoracic C. lumbar D. sacral E. enteric

A. No autonomic neurons emerge from the cervical cord. Sympathetic neurons emerge from the thoracic and lumbar levels of the spinal cord, and parasympathetic neurons emerge from the sacral cord (and also from the brain via the cranial nerves). "Enteric" is not a spinal cord level.

9. Pick the answer from the list below that best matches each description. Each answer is used once. ANSWERS Dorsal column system Lateral inhibition Somatotopic organization DESCRIPTION A. Sensory afferents from each part of the body surface project to different parts of the somatosensory cortex. B. Enhances two-point discrimination C. Carries sensory information regarding touch, light pressure, muscle length and tension, and limb position

A. Somatotopic organization B. Lateral inhibition C. Dorsal column system

5. Pick the answer from the list below that best matches each description. Each answer is used once. ANSWERS Hypophysis (pituitary) Limbic system Cerebellum Reticular formation (reticular activating system) Thalamus DESCRIPTION A. Major relay station in the anterolateral system. B. Sets the general level of behavioral arousal. C. Emotional "center" of the brain. D. Coordinates balance and movement. E. "Master gland" of the body

A. Thalamus B. Reticular formation (reticular activating system) C. Limbic system D. Cerebellum E. Hypophysis (pituitary)

10. Put the following, scrambled sequence of events in order, starting with tapping the patellar tendon. A. Using a small rubber hammer, a physician taps a patient's patellar tendon. B. Increased action potential frequency in Group Ia and II afferent neurons from patient's quadriceps muscle. C. Patient's quadriceps muscle contracts briefly. D. Lower leg extends (i.e., brief "kick") E. Excitation of somatic efferent neurons to the quadriceps muscle; inhibition of somatic efferent neurons to hamstrings muscle. F. Activation of stretch receptors in muscle spindles of quadriceps muscle. G. Passive stretch of quadriceps muscle.

A. Using a small rubber hammer, a physician taps a patient's patellar tendon. G. Passive stretch of quadriceps muscle. F. Activation of stretch receptors in muscle spindles of quadriceps muscle. B. Increased action potential frequency in Group Ia and II afferent neurons from patient's quadriceps muscle. E. Excitation of somatic efferent neurons to the quadriceps muscle; inhibition of somatic efferent neurons to hamstrings muscle. C. Patient's quadriceps muscle contracts briefly. D. Lower leg extends (i.e., brief "kick")

4. Which of the following is the most valid contrast between myelinated and non- myelinated neurons? Myelinated neurons Non-myelinated neurons A. faster propagation of action potentials slower propagation of action potentials B. carry efferent action potentials carry afferent action potentials C. carry afferent action potentials carry efferent action potentials D. in autonomic nervous system in somatic nervous system E. in peripheral nervous system in central nervous system

A. faster propagation of action potentials slower propagation of action potentials

7. Pick the neurotransmitter from the list below that best matches each description. Each answer may be used once, more than once, or not at all. NEUROTRANSMITTERS Opiate neurotransmitter (e.g. enkephalin) Acetylcholine (ACh) GABA Norepinephrine (NE) Glutamate Substance P DESCRIPTION A. Descending neurons from the reticular activating system exert pre-synaptic inhibition on primary nociceptor afferent neurons. B. Neurotransmitter released when a local axon "reflex" is activated by a nociceptive stimulus. C. Neurotransmitter released at the somatic neuromuscular junction. D. Excitatory neurotransmitter released by interneurons that make synaptic contact with somatic efferent neurons. E. One of the inhibitory neurotransmitter released by interneurons that make synaptic contact with somatic efferent neurons.

A. opiate neurotransmitter B. Substance P C. Acetylcholine D. Glutamate E. GABA

7. Within the cervical spinal cord, you would you find cell bodies of ______________________________. [Which of the following would correctly go in the blank? One or more answers may be correct.] A. somatic efferent (alpha motor) neurons B. somatic afferent neurons from nociceptors C. anterolateral tract neurons D. Visceral afferent neurons

A. somatic efferent (alpha motor) neurons C. anterolateral tract neurons

3. Within the cervical spinal cord, you would you find cell bodies of ______________________________. [Which of the following would correctly go in the blank? One or more answers may be correct.] A. somatic efferent (alpha motor) neurons B. cortico-spinal (pyramidal) tract neurons C. gamma motor neurons D. somatic afferent neurons from nociceptors E. anterolateral tract neurons F. somatic afferent neurons from muscle spindle and Golgi tendon organs

A. somatic efferent (alpha motor) neurons C. gamma motor neurons E. anterolateral tract neurons

7. A runner suffers from cold, painful finger tips because of excessively constricted blood vessels in the skin (Raynaud's disease). Which autonomic dysfunction is most likely to be involved? A. abnormally low concentration of epinephrine in the blood B. blood vessels abnormally sensitive to the normal sympathetic neurotransmitter C. blood vessels abnormally sensitive to acetylcholine D. abnormally low parasympathetic nerve activity E. blood vessels insensitive to epinephrine

B Norepinephrine, the normal sympathetic neurotransmitter, causes constriction of blood vessels in the skin. Sympathetic nerve activity to the skin is generally elevated during exercise. Excessive vasoconstriction in response to norepinephrine would greatly reduce skin blood flow, which would leave the skin cold and hypoxic (low oxygen), a painful condition. Choice A is wrong because epinephrine constricts skin blood vessels; thus, abnormally low epinephrine in the blood would allow skin vessels to dilate. An insensitivity of blood vessels to epinephrine (choice E) would have the same effect. Choice C is wrong, because: (1) the autonomic nerves going to skin blood vessels release norepinephrine, not acetylcholine, (2) acetylcholine levels in the blood are generally not high enough to affect blood vessels, and (3) acetylcholine, if present in high enough concentrations to have an effect, would cause blood vessels to dilate, not constrict. Choice D is wrong, because there are no parasympathetic neurons on skin blood vessels, so parasympathetic activity does not affect skin blood flow.

19. Which type of drug would be best to dilate the skin blood vessels of the runner with Raynaud's disease? (See Study Question #7 above.) A. alpha adrenergic agonist B alpha adrenergic antagonist C. muscarinic cholinergic agonist D. muscarinic cholinergic antagonist E. nicotinic (N Nerve) cholinergic antagonist

B Stimulation of alpha adrenergic receptors causes vasoconstriction of skin blood vessels. In a patient with Raynaud's disease, the skin vessels are abnormally sensitive to alpha adrenergic agonists. The most direct treatment would be to block this response with an alpha adrenergic antagonist. A muscarinic cholinergic agonist would also dilate skin blood vessels, but this would be counteracting the symptom without attacking the problem. Unfortunately, both alpha antagonists and cholinergic agonists tend to cause unpleasant and troublesome side effects (e.g., nausea and dangerous falls in blood pressure, called hypotension).

18. To dilate a patient's pupils in preparation for an eye examination, you could use eye drops that contained either an __________ or a __________. A. alpha adrenergic agonist....... muscarinic cholinergic agonist B. alpha adrenergic agonist....... muscarinic cholinergic antagonist C. alpha adrenergic antagonist ....... muscarinic cholinergic agonist D. alpha adrenergic antagonist ....... muscarinic cholinergic antagonist

B Stimulation of alpha receptors (a-receptors) would increase the contraction of the radial muscles of the iris and dilate the pupil. A muscarinic cholinergic antagonist would dilate the pupils by blocking parasympathetically mediated contraction of the pupillary sphincter muscles. Of course, a cholinergic antagonist would have the effect only if the parasympathetic nerves were active (i.e., a blocking drug will only have an effect if there is an ongoing action to block). In fact, the parasympathetic nerves to the pupils are usually active in resting persons, and eye drops containing muscarinic cholinergic antagonists (e.g. atropine) are often used to dilate the pupils of patients before eye exams. Historically, atropine was called belladonna ("beautiful woman"), because is was used by Italian women to dilate their pupils and make their eyes more attractive.

20. Asthma is an allergic constriction of the bronchial airways due to an increase in the intrinsic (spontaneous) contraction of the bronchial smooth muscle. Which type of drug would be the best treatment? A. alpha adrenergic agonist B. beta adrenergic agonist C. beta adrenergic antagonist D. muscarinic cholinergic agonist E. muscarinic cholinergic antagonist

B activation of bronchial beta receptors decreases the contraction of bronchial smooth muscle below its intrinsic level, and therefore directly counteracts the problem. Indeed, the active ingredient in most of the "rescue inhalers" used by asthmatics is a beta adrenergic agonist. The most common drug used for this purpose is albuterol, which is a selective beta- 2 adrenergic agonist. Perhaps you chose Answer E, because you were thinking that a muscarinic cholinergic antagonist would help dilate the bronchi by blocking an ongoing parasympathetically mediated bronchial constriction. However, the victim of an asthma attack is usually very alarmed and anxious; and they would therefore have very little, if any, parasympathetic activity to be blocked.

5. Which of the following would most directly activate stretch receptors in a muscle spindle in the biceps muscle? A. passive shortening of the biceps B. active contraction of intrafusal muscle fibers in the biceps C. active contraction of extrafusal muscle fibers in the biceps D. action potentials in group Ia or II afferent fibers innervating the muscle spindle E. action potentials in group Ib afferent fibers innervating the Golgi tendon organ in the biceps tendon

B. active contraction of intrafusal muscle fibers in the biceps

4. Typically, sympathetic ganglia are: A. located within the central nervous system B. located within the walls of the organs they innervate (i.e., within their effector organs) C. located outside of the central nervous system and away from their effector organs D. restricted to the thoracic and lumbar levels of the spinal cord E. found only in the abdomen

C Autonomic ganglia are located outside of the central nervous system; they are part of the peripheral nervous system. Whereas parasympathetic ganglia are characteristically microscopic and located within the walls of their effector organs, sympathetic ganglia are located in discrete structures some distance away from their effector organs. Choice D is a tricky one. It's true that the pre-ganglionic sympathetic neurons emerge only from the thoracic and lumbar levels of the spinal cord. However, when these pre-ganglionic neurons enter the sympathetic chains, they may travel up to the highest cervical levels or down to the lowest sacral levels before making synaptic contact with post-ganglionic sympathetic neurons. That is, sympathetic ganglia are found at all levels of the sympathetic chain, not just at the thoracic and lumbar levels. In addition, some additional sympathetic ganglia are found out in the abdomen.

14. Which of the following statements is TRUE? A. All sympathetic responses are evident during a defense-alarm reaction. B. The sympathetic nervous system is typically activated in an all-or-none fashion. C. Parasympathetic activity is typically low during a defense-alarm reaction. D. If the sympathetic and parasympathetic nerves to the bronchial airways were cut, the bronchial smooth muscle would relax completely. E. The secretion of tears by the lacrimal glands could be increased by administration of an adrenergic agonist.

C Choice C is true, because parasympathetic activity is typically decreased to low levels when the body is reacting to great physical or emotional stress. During such a defense- alarm reaction, most sympathetic nerves are strongly activated; but Choice A is wrong because not all sympathetic nerves are activated. The sympathetic response of ejaculation, for example, does not typically occur during a fear, fight, or flight situation! Choice B is wrong, because specific sympathetic responses are typically and normally activated in a discrete, graded fashion, as appropriate for the particular situation. The sympathetic system is rarely, if ever, "all the way on" . . . sympathetic responses don't all occur together, even during extreme physical or emotional stress. Choice D is wrong, because bronchial smooth muscle, like other autonomic effector tissues, has an intrinsic, spontaneous activity of its own; in the absence of any autonomic nerve input, bronchial smooth muscle would be in a state of partial contraction. Choice E is wrong, because the lacrimal glands don't have adrenergic receptors and so don't respond to adrenergic agonists.

21. Which of the following would act most directly to decrease the heart rate in an exercising subject? A. muscarinic cholinergic antagonist B. nicotinic (N Muscle) cholinergic agonist C. beta adrenergic antagonist D. alpha adrenergic agonist E. alpha adrenergic antagonist

C The increase in heart rate during exercise is caused by a simultaneous decrease in parasympathetic activity and increase in sympathetic activity to the heart. The sympathetic activity acts via cardiac beta-1 receptors to increase heart rate above its intrinsic level (which, in adult humans, is about 110 beats per minute). A beta adrenergic antagonist would lower heart rate back toward its intrinsic level by blocking this sympathetic effect. However, it is important to emphasize that the only way to get heart rate below its intrinsic level would be through parasympathetic activation or administration of a muscarinic cholinergic agonist.

2. Autonomic neurons found within a skeletal muscle (like the gastrocnemius) would be most likely to cause: A. contraction of extrafusal muscle fibers B. relaxation of intrafusal muscle fibers C. constriction of blood vessels within the muscle D. sensations of pain E. conscious awareness of muscle tension

C autonomic (sympathetic) neurons are found in all the body's skeletal muscles, where they innervate the smooth muscle cells in the walls of the blood vessels. Sympathetic activation increases smooth muscle contraction, which constricts the blood vessels and reduces blood flow. The intrafusal and extrafusal muscle fibers are innervated by somatic motor neurons, not by sympathetic neurons. Conscious sensations from muscles depend on activation of sensory afferent neurons. Sympathetic neurons, by contrast, carry only efferent action potentials.

8. Stepping on a sharp object with the left foot normally causes all of the following EXCEPT: A. excitation of motor neurons to ipsilateral leg flexor muscles B. inhibition of motor neurons to ipsilateral leg extensor muscles C. excitation of motor neurons to contralateral leg flexor muscles D. excitation of sympathetic efferent neurons to the heart E. activation of the anterolateral system projecting to the contralateral somatosensory cortex

C. excitation of motor neurons to contralateral leg flexor muscles

1. For each of the following structures, state whether it is part of the peripheral nervous system (PNS) or the central nervous system (CNS). For each structure that is in the CNS, state whether it is in the brain or the spinal cord. Cerebral cortex Ventral horn Thalamus Hypothalamus Basal nuclei (basal ganglia) Dorsal root ganglion Limbic system Brainstem

Cerebral cortex - CNS (brain) Ventral horn - CNS (spinal cord) Thalamus - CNS (brain) Hypothalamus - CNS (brain) Basal nuclei (basal ganglia) - CNS (brain) Dorsal root ganglion - PNS Limbic system - CNS (brain) Brainstem - CNS (brain)

11. Substance X is a muscarinic cholinergic agonist. This means that Substance X: A. binds to muscarinic cholinergic receptors on effector tissues B. activates muscarinic ercholinergic receptors on effector tissues C. causes exactly the same effects as parasympathetic activation D. A and B are correct E. A, B, and C are correct

D By definition, a muscarinic cholinergic agonist is a substance that binds to and activates muscarinic cholinergic receptors. Choice C is wrong, because a muscarinic cholinergic agonist (when administered into the blood stream) would activate all muscarinic cholinergic receptors, not just those innervated by parasympathetic neurons. For example, in addition to mimicking parasympathetic effects, a muscarinic cholinergic agonist would cause dilation of all blood vessels (not just those in the external genitalia) and would mimic the sympathetic -cholinergic effect of sweating.

12. Substance Y is an adrenergic agonist. This means that Substance Y: A. binds to adrenergic receptors on effector tissues B. activates adrenergic receptors on effector tissues C. causes exactly the same effects as sympathetic activation D. A and B are correct E. A, B, and C are correct

D By definition, an adrenergic agonist is a substance that binds to and activates adrenergic receptors. Choice C is wrong, because an adrenergic agonist (when administered into the blood stream) would not bring about all sympathetic effects (specifically, an adrenergic agonist would not cause generalized sweating). Also, activation of sympathetic nerves always causes constriction of blood vessels, but a beta adrenergic agonist, circulating in the blood stream, causes blood vessels in skeletal muscles to dilate.

22. Coronary blood vessels could be dilated by administration of: A. a beta adrenergic agonist B. a muscarinic cholinergic agonist C. an alpha adrenergic agonist D. A and B are correct E. A, B, and C are correct

D Coronary arterioles have beta adrenergic receptors and muscarinic cholinergic receptors, both of which cause vasodilation when stimulated. Choice C is wrong, because activation of alpha adrenergic receptors on coronary arterioles causes vasoconstriction.

16. Which of the following organs receive(s) dual, reciprocal innervation? A. the blood vessels in the penis and clitoris B. the urinary bladder C. the pilomotor muscles D. A and B are correct E. A, B, and C are correct

D The pilomotor muscles do not receive parasympathetic innervation. If you missed this question, refer back the table of "Most Important Effects of Autonomic Nerve Activity". Choices A and B are true, because the genital blood vessels and the urinary bladder receive both sympathetic and parasympathetic innervation, and the two systems have opposing effects.

5. Adrenal medullary cells and post-ganglionic sympathetic neurons are both activated by: A. the neurotransmitter acetylcholine B. preganglionic sympathetic neurons C. sweating D. A and B are correct E. A, B, and C are correct

D adrenal medullary cells, like all post-ganglionic sympathetic neurons, are activated by the acetylcholine that is released from sympathetic pre-ganglionic neurons. Choice C was put in just to confuse you; although ACh is the neurotransmitter that causes sweating, it's nonsense to say that sweating activates post-ganglionic neurons or adrenal medullary cells.

3. When you step on a sharp object with your foot, the sensation of pain takes place in the: A. dorsal horn of the spinal cord B. dorsal root ganglion of the spinal cord C. nociceptive nerve endings D. cerebral cortex E. thalamus

D. cerebral cortex

17. Parasympathetic activation: A. increases the contraction of the pupillary sphincter muscle above its intrinsic level B. decreases the heart rate below its intrinsic level C. increases the secretion of bronchial mucous glands above their intrinsic level D. A and B are correct E. A, B, and C are correct

E Like all autonomic effector tissues, the pupillary sphincters, heart, and bronchial glands have a spontaneous, intrinsic activity. What the autonomic nerves do is either to increase the effector activity above its intrinsic level or decrease it below its intrinsic level. The table of "Most Important Effects of Autonomic Nerve Activity" indicates the direction of the effect.

13. Which of the following statements is TRUE? A. All sympathetic effects are adrenergically mediated. B. All the effects of sympathetic nerves could be canceled out by activating parasympathetic nerves. C. All the effects of sympathetic nerves could be canceled out by administering a cholinergic agonist. D. All of the effects of a cholinergic agonist could be canceled out by administering an adrenergic agonist. E. None of the above is true.

E None of these statements is true. Choice A is wrong, because sweating is a sympathetic cholinergic response. Choice B is wrong, because there is no reciprocal, parasympathetic effect for several sympathetic responses (e.g. there is no parasympathetic counter-effect for sympathetic effects like ejaculation, piloerection, sweating, or constriction of blood vessels in most organs). Choice C is wrong, because a cholinergic agonist would have no counter- effect on sympathetic ejaculation or piloerection; and a cholinergic agonist would actually enhance sympathetic sweating. Choice D is wrong, because an adrenergic agonist would have no counter-effect on cholinergically-induced sweating or lacrimal gland secretion. These distinctions have great practical importance in clinical medicine.

23. To prepare a patient for general anesthesia, the anesthesiologist must insert a breathing tube into the trachea. What type of drug would be effective in preventing reflex contractions of the laryngeal muscles during the insertion of a trachea tube? (Hint: The laryngeal muscles are skeletal muscles, not smooth muscles.) A. alpha adrenergic antagonist B. beta adrenergic agonist C. muscarinic cholinergic antagonist D. nicotinic (N Nerve) cholinergic antagonist E. nicotinic (N Muscle) cholinergic antagonist

E Skeletal muscles contract when their nicotinic (N Muscle)cholinergic receptors are activated by ACh, which is the somatic neurotransmitter. A N Muscle-cholinergic antagonist binds to these receptors and prevents their activation by ACh or any other agonist. The classic N Muscle-antagonist is curare, a plant toxin discovered and previously used by some South American Indian tribes as an arrowhead poison. Today, anesthesiologists use a short- acting drug that is closely related to curare to paralyze skeletal muscles of patients during insertion of trachea tubes.

3. Which of the following is not an exocrine gland? A. tear gland (lacrimal gland) B. sweat gland C. acid-secreting gland of the stomach D. mucous-secreting gland of the bronchial airway E. pituitary gland

E The pituitary is the "master gland" of the endocrine system; like all endocrine glands, it dumps its hormonal secretions directly into the blood stream. All the other glands listed dump their secretions onto the "outside" of the body; they are exocrine glands and are under autonomic control.

6. Blood pressure would go down if: A. parasympathetic activity to the heart were decreased B. sympathetic activity to the heart were increased C. norepinephrine were administered intravenously D. All of the above are correct E. None of the above is correct

E- Choices A, B, and C would all increase blood pressure. Decreasing parasympathetic activity would allow heart rate to increase; the heart would then pump more blood, and blood pressure would go up. Sympathetic activation would also increase heart rate; in addition, it would increase blood pressure by raising the heart's contractility and by constricting blood vessels. Norepinephrine, the sympathetic neurotransmitter, would have the same effects.

8. Sensory nerve endings associated with hairs of skin are characterized by all of the following EXCEPT: A. low threshold B. rapid adaptation C. both "on response" and "off response" D. large, myelinated afferent neurons E. afferent pathway follows the anterolateral system (this is not correct, because the sensation of hair movement is mediated by the dorsal column system not the anterolateral system).

E. afferent pathway follows the anterolateral system (this is not correct, because the sensation of hair movement is mediated by the dorsal column system not the anterolateral system).

6. The following list describes events in a particular reflex (inverse myotatic reflex) that affects the biceps muscle. This list of events is scrambled (i.e. not in correct sequence). First, put the list of events in correct sequence. Next, match each event with one of the 5 general components of a reflex. A. Inhibitory neurotransmitter released from spinal interneurons B. Forceful stretch of Golgi tendon organ in biceps tendon C. Biceps muscle relaxes D. Decreased frequency of action potentials in somatic efferent neurons that innervate the biceps muscle E. Increased frequency of action potentials in Group Ib afferent neurons from biceps tendon

In order: B. Forceful stretch of Golgi tendon organ in biceps tendon E. Increased frequency of action potentials in Group Ib afferent neurons from biceps tendon A. Inhibitory neurotransmitter released from spinal interneurons D. Decreased frequency of action potentials in somatic efferent neurons that innervate the biceps muscle C. Biceps muscle relaxes

Which statement is TRUE about how Endolymph contributes to hearing? a. Endolymph is high in K+ so opening of Voltage-Gated K+ channels depolarizes Hair cell b. Endolymph is high in Na+ so opening of Voltage-Gated Na+ channels depolarizes Hair cell c. Endolymph is high in K+ so opening of Mechanically-Gated K+ channels depolarizes Hair cell d. Endolymph is low in K+ so opening of Mechanically-Gated K+ channels hyperpolarizes Hair cell e. Endolymph is low in Na+ so opening of Mechanically-Gated Na+ channels hyperpolarizes Hair cell

c. Endolymph is high in K+ so opening of Mechanically-Gated K+ channels depolarizes Hair cell

In Phototransduction the Vm of the plasma membrane _______ due to the _________ of cGMP -Gated Channels a. Depolarizes; Closing b. Depolarizes; Inactivation c. Hyperpolarizes; Closing d. Hyperpolarizes; Opening e. None of the above are true

c. Hyperpolarizes; Closing