Quiz
Human Phys Mid 2
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Fragen in diesem Quiz (165)
1A secondary endocrine organ is ________.
- AA) An organ that secretes at least two hormones
- BB) An organ that receives communication from at least two hormones
- CC) An organ that secretes tropic hormones
- DD) An organ that is the target of tropic hormones
- EE) An organ that secretes hormones, but is better known for another function
2Which of the following endocrine organs is located in the brain?
- AA) Pancreas
- BB) Adrenal Gland
- CC) Hypothalamus
- DD) Gonads
- EE) Thymus
3What is another name for the posterior lobe of the pituitary gland?
- AA) adenohypophysis
- BB) neurohypophysis
- CC) pineal gland
- DD) melanocyte
- EE) paraventricular nucleus
4What hormone released by the posterior pituitary functions in uterine contraction and milk letdown in the breast?
- AA) Somatomedin
- BB) Vasopressin
- CC) Antidiuretic hormone
- DD) Oxytocin
- EE) Prolactin
5Secretion of hormones from the anterior pituitary is stimulated by ________ released from the _________.
- AA) antidiuretic hormone : hypothalamus
- BB) inhibiting hormones : posterior pituitary
- CC) oxytocin : hypothalamus
- DD) stimulating hormones : posterior pituitary
- EE) releasing hormones : hypothalamus
6What ensure(s) that blood levels of a specific releasing hormone are locally high in order to stimulate the pituitary?
- AA) degradation rates of tropic hormones
- BB) affinity of the tropic hormones
- CC) hepatic portal system
- DD) hypothalamic-pituitary portal system
- EE) pulsatility of tropic hormone release
7Which of the following is NOT a hormone released from the anterior pituitary?
- AA) prolactin inhibiting hormone
- BB) luteinizing hormone
- CC) follicle stimulating hormone
- DD) growth hormone
- EE) adrenocorticotropic hormone
8Which tropic hormone is responsible for controlling the release of follicle stimulating hormone from the anterior pituitary?
- AA) growth hormone releasing hormone
- BB) corticotropin releasing hormone
- CC) follicle releasing hormone
- DD) gonadotropin releasing hormone
- EE) follicle stimulating releasing hormone
9Which of the following correctly describes a pathway for secretion of a hormone under the control of tropic hormones?
- AA) CRH stimulates ACTH release, which stimulates somatomedin release.
- BB) PRH stimulates PH release, which stimulates prolactin release.
- CC) GHRH stimulates GH release, which stimulates insulin-like growth factor release.
- DD) GnRH stimulates PH release, which stimulates prolactin release.
- EE) TRH stimulates TSH release, which stimulates thymosin release.
10Which of the following tropic hormones is a catecholamine?
- AA) prolactin-releasing hormone
- BB) prolactin-inhibiting hormone
- CC) growth hormone-inhibiting hormone
- DD) growth hormone
- EE) luteinizing hormone
11Which of the following is a correct example of long-loop negative feedback?
- AA) TSH inhibits the release of TRH.
- BB) TSH stimulates the release of TRH.
- CC) Glucocorticoids inhibit the release of CRH.
- DD) FSH inhibits the release of GnRH.
- EE) GH stimulates the release of GHIH.
12Which of the following is a correct example of short-loop negative feedback?
- AA) Thyroid hormones inhibit the release of TRH.
- BB) Thyroid hormones inhibit the release of TSH.
- CC) TRH stimulates the release of thyroid hormones.
- DD) TSH inhibits the release of TRH.
- EE) TRH inhibits the release of TSH.
13The release of ________ from the pineal gland is important for establishing ________.
- AA) melatonin : thirst
- BB) prolactin : circadian rhythm
- CC) melatonin : circadian rhythm
- DD) prolactin : breast milk production
- EE) melanin : thirst
14The thyroid gland secretes what hormone?
- AA) thyroid hormones only
- BB) thymosin only
- CC) calcitonin only
- DD) both thyroid hormones and thymosin
- EE) both thyroid hormones and calcitonin
15What is triiodothyronine?
- AA) a catecholamine released from the adrenal cortex
- BB) a catecholamine released from the adrenal medulla
- CC) a thyroid hormone secreted from the thyroid gland
- DD) the hormone secreted from the thymus
- EE) the hormone secreted from the pineal gland
16Which of the following hormones is NOT released from the adrenal gland?
- AA) adrenocorticotropic hormone
- BB) aldosterone
- CC) cortisol
- DD) androgens
- EE) epinephrine
17Which of the following hormones is NOT secreted by the endocrine region of the pancreas?
- AA) insulin
- BB) glucagon
- CC) somatostatin
- DD) pancreatic polypeptide
- EE) glucocorticoids
18What layer of the adrenal cortex secretes mineralocorticoids?
- AA) zona reticularis only
- BB) zona fasciculata only
- CC) zona glomerulosa only
- DD) both zonae reticularis and fasciculata
- EE) both zonae reticularis and glomerulosa
19What layer of the adrenal cortex secretes androgens?
- AA) zona reticularis only
- BB) zona fasciculata only
- CC) zona glomerulosa only
- DD) both zonae reticularis and fasciculata
- EE) both zonae reticularis and glomerulosa
20What region of the adrenal gland secretes epinephrine?
- AA) Zona reticularis
- BB) Zona fasciculata
- CC) Zona golmerulosa
- DD) Medulla
- EE) Zonae reticularis, fasciculata and golmerulosa
21What cells secrete epinephrine from the adrenal medulla?
- AA) chromaffin cells
- BB) A cells
- CC) B cells
- DD) D cells
- EE) zona reticularis cells
22Which of the following is an incorrect association between pancreatic cell type and hormone secreted?
- AA) Alpha cells secrete glucagon.
- BB) Beta cells secrete insulin.
- CC) Delta cells secrete somatostatin.
- DD) Epsilon cells secrete calcitonin.
- EE) F cells secrete pancreatic polypeptide.
23Which of the following hormones is NOT secreted by gonads?
- AA) testosterone
- BB) oxytocin
- CC) androstenedione
- DD) estradiol
- EE) progesterone
24What anterior pituitary hormone is NOT a tropic hormone?
- AA) prolactin
- BB) growth hormone
- CC) adrenocorticotropic hormone
- DD) follicle stimulating hormone
- EE) luteinizing hormone
25Which of the following hormones regulates plasma calcium levels?
- AA) calcitonin only
- BB) oxytocin only
- CC) parathyroid hormone only
- DD) both calcitonin and oxytocin
- EE) both calcitonin and parathyroid hormone
26What hormone is secreted by the heart?
- AA) erythropoietin
- BB) thymosin
- CC) atrial natriuretic peptide
- DD) epinephrine
- EE) somatostatin
27Where does the neural input for circadian rhythmicity of hypothalamic tropic hormones originate?
- AA) suprachiasmatic nucleus
- BB) paraventricular nucleus
- CC) supraoptic nucleus
- DD) pineal gland
- EE) cerebrum
28Abnormal hormone secretions from an endocrine gland due to altered tropic hormone release are called ________.
- AA) primary secretion disorders
- BB) hypersecretions
- CC) secondary secretion disorders
- DD) hyposecretions
- EE) tertiary secretion disorders
29Which of the following changes in plasma levels would be observed in a primary
hyposecretion of cortisol?- AA) increased CRH, increased ACTH, and increased cortisol
- BB) decreased CRH, decreased ACTH, and decreased cortisol
- CC) increased CRH, increased ACTH, and decreased cortisol
- DD) decreased CRH, decreased ACTH, and increased cortisol
- EE) increased CRH, decreased ACTH, and decreased cortisol
30A person has a tumor in the hypothalamus causing an excess in TRH secretion. Which of the following correctly describes changes in plasma levels of hormones?
- AA) increased TRH, increased TSH, and increased thyroid hormones
- BB) decreased TRH, decreased TSH, and decreased thyroid hormones
- CC) increased TRH, increased TSH, and decreased thyroid hormones
- DD) decreased TRH, decreased TSH, and increased thyroid hormones
- EE) increased TRH, decreased TSH, and decreased thyroid hormones
31A person has a tumor in the anterior pituitary causing a decrease in ACTH secretion. Which of the following correctly describes changes in plasma levels of hormones?
- AA) increased CRH, increased ACTH, and increased cortisol
- BB) decreased CRH, decreased ACTH, and decreased cortisol
- CC) increased CRH, increased ACTH, and decreased cortisol
- DD) decreased CRH, decreased ACTH, and increased cortisol
- EE) increased CRH, decreased ACTH, and decreased cortisol
32Which of the following best describes the mechanism of insulin catabolism in target cells?
- AA) degradation by lysosomes following receptor-mediated endocytosis
- BB) degradation by insulin-degrading enzyme following receptor-mediated endocytosis
- CC) degradation by proteases in the extracellular fluid
- DD) degradation by mitochondrial enzymes following receptor-mediated endocytosis
- EE) degradation by peroxisomal enzymes
33When the response to two hormones is equal to the sum of their individual responses, the response is described as ________.
- AA) permissive
- BB) antagonized
- CC) synergistic
- DD) additive
- EE) agonistic
34When the response to two hormones is greater than the sum of the individual responses, the response is described as ________.
- AA) permissive
- BB) antagonized
- CC) synergistic
- DD) additive
- EE) agonistic
35A releasing hormone is a type of tropic hormone.
- ARichtig
- BFalsch
36The hypothalamus is connected to the posterior pituitary by the hypothalamic-pituitary portal system.
- ARichtig
- BFalsch
37The secretion of hormones from the anterior pituitary is controlled by hypothalamic tropic hormones.
- ARichtig
- BFalsch
38Growth hormone functions as both a tropic hormone and as a hormone that acts on target cells throughout the body.
- ARichtig
- BFalsch
39The only non-peptide/protein tropic hormone is somatostatin.
- ARichtig
- BFalsch
40The only non-peptide/protein tropic hormone is dopamine.
- ARichtig
- BFalsch
41The release of LG and FSH by the anterior pituitary is under control of the same hypothalamic tropic hormone.
- ARichtig
- BFalsch
42In a short negative feedback loop, a tropic hormone from the anterior pituitary inhibits the release of its own releasing hormone from the hypothalamus.
- ARichtig
- BFalsch
43The hormone thymosin is released from the thyroid gland.
- ARichtig
- BFalsch
44The thyroid gland secretes parathyroid hormone.
- ARichtig
- BFalsch
45The parathyroid gland secrete calcitonin.
- ARichtig
- BFalsch
46The zona fasciculata secretes both androgens and glucocorticoids.
- ARichtig
- BFalsch
47All hormones of the adrenal cortex are steroid hormones.
- ARichtig
- BFalsch
48The skin is necessary for the activation of calcitonin.
- ARichtig
- BFalsch
49Insulin-like growth factors are secreted by the liver and function to promote tissue growth.
- ARichtig
- BFalsch
50The magnitude of response at the target cell depends on both the concentration of hormone and the concentration of receptor.
- ARichtig
- BFalsch
51All hormones are required to be bound to carrier proteins in order to be active.
- ARichtig
- BFalsch
52Hormones transported in blood bound to proteins are metabolized more slowly more than those traveling dissolved in plasma.
- ARichtig
- BFalsch
53Regulation of insulin release by blood glucose levels is an example of humoral control of hormone secretion.
- ARichtig
- BFalsch
54Growth hormone has direct action on target cells throughout the body.
- ARichtig
- BFalsch
55Much of the insulin is removed from the blood as it passes through the liver.
- ARichtig
- BFalsch
56Kidney cells contain insulin-degrading enzyme.
- ARichtig
- BFalsch
57A skeletal muscle is composed of a number of ________, each composed of many muscle fibers bundled by connective tissue.
- AA) fascicles
- BB) myofibrils
- CC) muscle cells
- DD) myofilaments
- EE) sarcomeres
58What structure composed of connective tissue transmits force from contracting skeletal muscle to bone?
- AA) myofibril
- BB) fascicle
- CC) tendon
- DD) ligament
- EE) aponeurosis
59What is the saclike membranous network that surrounds each myofibril called?
- AA) sarcolemma
- BB) sarcoplasmic reticulum
- CC) transverse tubule
- DD) nucleus
- EE) mitochondrion
60The fundamental repeating unit of the myofibril called a ________ gives skeletal muscle its striated appearance, and is bordered by ________.
- AA) crossbridge : Z lines
- BB) sarcomere : M lines
- CC) sarcomere : I bands
- DD) sarcomere : Z lines
- EE) crossbridge : A bands
61What is the region of the striated muscleʹs banding patterns that contains only the connections between the tails of myosin molecules ?
- AA) A band
- BB) I band
- CC) H zone
- DD) Z line
- EE) M line
62The contractile portion of the thin filament is composed of what protein?
- AA) myosin
- BB) tropomyosin
- CC) troponin
- DD) actin
- EE) titin
63What is the protein component of the thin filament that binds to calcium thereby initiating skeletal muscle contraction?
- AA) myosin
- BB) tropomyosin
- CC) troponin
- DD) actin
- EE) titin
64Which of the following is a structural protein that extends along each thick filament from M line to Z line.
- AA) Titin
- BB) Actin
- CC) Myosin
- DD) Tropomyosin
- EE) Troponin
65The shortening of a skeletal muscle fiber during contraction involves which of the following?
- AA) the thick filaments shortening
- BB) the thin filaments shortening
- CC) the sarcomeres shortening
- DD) the A bands shortening
- EE) the Z lines not changing their position
66During skeletal muscle contraction, as the muscle shortens, the thick and thin filaments ________.
- AA) shorten
- BB) slide past one another
- CC) do not interact
- DD) condense
- EE) lengthen
67When a skeletal muscle is passively stretched, that cell has a tendency to spring back once the force that was stretching the muscle is removed due to ________.
- AA) the passive interaction between actin and myosin (no energy required)
- BB) the active interaction between actin and myosin (energy required)
- CC) titin acting as a spring using the energy stored by the stretching
- DD) actin and myosin acting as a spring using the energy stored by the stretching
- EE) the elastic connective tissue that surrounds the muscle cells and fascicles
68The repeated, oscillating interaction between actin and myosin that results in the generation of force by a skeletal muscle cell is called what?
- AA) crossbridge cycling
- BB) the sliding-filament model
- CC) Z line interaction
- DD) sarcomeric facilitation
- EE) titin cycling
69What converts the myosin head into the high-energy state?
- AA) binding to ATP only
- BB) binding to actin
- CC) the condensation of ATP
- DD) the hydrolysis of ATP
- EE) binding to titin
70The release of an inorganic phosphate from the myosin molecule directly results in which of the following?
- AA) development of rigor
- BB) power stroke
- CC) cocking of the myosin head
- DD) binding of actin to myosin
- EE) breaking of the actin myosin complex
71In order for crossbridge cycling to occur, the actin-myosin complex must be broken by which of the following?
- AA) binding of tropomyosin to myosin
- BB) binding of ATP to actin
- CC) binding of the troponin complex to actin
- DD) conformational change that occurs as the myosin head changes from the high to low energy state
- EE) binding of ATP to myosin
72The sequence of events that links the action potential to changes in skeletal muscle force development is called what?
- AA) the sliding-filament model
- BB) crossbridge cycling
- CC) myoaction coupling
- DD) excitation-contraction coupling
- EE) oxidative phosphorylation
73During skeletal muscle contraction, multiple crossbridge cycles are occurring between the same thick and thin filament. Which of the following best describes this process?
- AA) Crossbridge cycling is highly synchronized between a certain thick and thin filament.
- BB) Crossbridge cycling is asynchronous between a certain thick and thin filament.
- CC) No more than one myosin head links to the thin filament at the same time.
- DD) No more than one myosin head detaches from the thin filament at the same time.
- EE) Tropomyosin only exposes one binding site on actin at a time allowing only one crossbridge to form with actin at a given time.
74Contraction of skeletal muscle fibers is stimulated by what type of neuron?
- AA) autonomic neurons
- BB) sympathetic neurons
- CC) motor neurons
- DD) parasympathetic neurons
- EE) afferent neurons
75Which of the following is NOT a specialization observed at the neuromuscular junction?
- AA) the high density of acetylcholine receptors in the motor end plate
- BB) Every action potential that reaches the axon terminal of the motor neuron will generate an action potential in the muscle fiber.
- CC) The motor end plate is relatively large compared with other synapses.
- DD) The terminal bouton fans out over a wide area of the sarcolemma.
- EE) Each muscle fiber is innervated by multiple motor neurons.
76Increases in the amount of cytoplasmic calcium required to initiate a muscle contraction are
mediated by the coupling between a ________ on the T tubule and a ________ on the
membrane of the sarcoplasmic reticulum.- AA) Dihydropyridine receptor: calcium pump
- BB) Dihydropyriridine receptor: ryanodine pump
- CC) Ryanodine receptor: calcium pump
- DD) Calcium pump: ryanodine receptor
- EE) Calcium-induced calcium release channel: dihydropyridine receptor
77Which of the following is the voltage sensor that initiates an increase in cytoplasmic calcium in response to action potential?
- AA) dihydropyridine receptor
- BB) ryanodine receptor
- CC) calcium pump
- DD) calcium-induced calcium release channel
- EE) sodium channel
78The binding of calcium to troponin will directly cause which of the following?
- AA) the binding of ATP to myosin
- BB) the further release of calcium into the cytoplasm
- CC) the movement of tropomyosin, thereby exposing the myosin-binding site on the actin molecule
- DD) the movement of tropomyosin, thereby exposing the actin-binding site on the myosin molecule
- EE) the hydrolysis of ATP
79What portion of a sarcomere shows up as light striations when viewed under a microscope?
- AA) A band
- BB) I band
- CC) H zone
- DD) M line
- EE) Z line
80Which of the following best describes the function of transverse (t) tubules and the
sarcoplasmic reticulum in skeletal muscle contraction?- AA) Action potentials in T tubules trigger the release of acetylcholine, which binds to receptors on the sarcoplasmic reticulum and triggers calcium release.
- BB) Action potentials in T tubules trigger the release of norepinephrine, which binds to receptors on the sarcoplasmic reticulum and triggers calcium release.
- CC) Action potentials in T tubules are detected by DHP receptors, which are coupled to ryanodine receptors in the sarcoplasmic reticulum and open channels for calcium.
- DD) Action potentials in T tubules are detected by ryanodine receptors, which are coupled to DHP receptors in the sarcoplasmic reticulum and open channels for calcium.
- EE) Action potentials in T tubules cause a depolarization of the sarcoplasmic reticulum membrane, thereby opening calcium channels to trigger calcium release.
81During the cross-bridge cycle, ATP binding to myosin causes which of the following?
- AA) the myosin head to attach to actin
- BB) the myosin head to detach from actin
- CC) the myosin head to swing forward pulling actin toward the M line
- DD) the myosin head to interact with calcium channels, triggering calcium release from the sarcoplasmic reticulum
- EE) the myosin head to be in its high-energy form
82What is the function of T tubules?
- AA) They store calcium
- BB) Actin and myosin are synthesized here
- CC) They conduct action potentials from the sarcolemma to the interior of the muscle cell
- DD) They provide elasticity to the muscle
- EE) They hold the thick filaments to the Z line
83What is a motor unit?
- AA) all the muscle fibers in a fascicle
- BB) all the myofibrils in a muscle fiber
- CC) a muscle fiber and all the motor neurons that innervate it
- DD) a motor neuron and all the muscle fibers it innervates
- EE) a spinal nerve and all the muscle fibers it innervates
84In order to allow discrete contractile events to occur, calcium is rapidly removed from the
cytoplasm via ________.- AA) calcium pumps (active transport of calcium)
- BB) dihydropyridine receptors
- CC) ryanodine channels
- DD) calcium-sequestering proteins in the cytoplasm
- EE) calcium-binding proteins on the sarcoplasmic reticulum
85Which of the following is NOT part of the process whereby skeletal muscles relax?
- AA) Sarcolemmal calcium channels open to allow the efflux of calcium.
- BB) The binding of calcium to a low-affinity site closes sarcoplasmic reticulum calcium channels.
- CC) A calcium pump actively removes calcium.
- DD) Amount of calcium bound to troponin decreases.
- EE) A myosin-binding site on the actin molecule is blocked by tropomyosin.
86What enzyme catalyzes the reaction that creates creatine phosphate?
- AA) creatine phosphatase
- BB) creatine hydrolase
- CC) creatine hydrogenase
- DD) creatine kinase
- EE) ATP hydrolase
87Since the creatine phosphorylation reaction is substrate driven, an increase in the concentration of creatine within a skeletal muscle fiber will directly have what effect?
- AA) increase creatine phosphate concentration
- BB) decrease creatine phosphate concentration
- CC) increase ATP generation
- DD) decrease creatine kinase activity
- EE) increase glucose metabolism
88During intense (heavy) exercise, the ability of oxidative phosphorylation to provide enough
ATP for force generation by the skeletal muscle is ________, thereby causing the muscle fiber
to derive energy from ________.- AA) enhanced : substrate-level phosphorylation
- BB) diminished : substrate-level phosphorylation
- CC) enhanced : fatty acids
- DD) enhanced : glucose
- EE) diminished : fatty acids
89As the intensity of exercise increases, the muscles switch from oxidative to substrate-level
phosphorylation, resulting in the increased generation of which of the following?- AA) lactic acid
- BB) water from the electron transport chain
- CC) glucose
- DD) fatty acid
- EE) ATP
90When an action potential is generated within a motor neuron, ________.
- AA) the muscle cells of the motor unit will occasionally contract
- BB) only select muscle cells within the motor unit are stimulated to contract
- CC) every muscle cell of the motor unit is stimulated to contract
- DD) the muscle cells from a neighboring motor unit will contract
- EE) all of the muscle cells within the motor unit are stimulated to relax
91What is the longest phase of a twitch?
- AA) latent
- BB) contraction
- CC) plateau
- DD) relaxation
- EE) initial
92Which of the following is NOT part of the explanation for the all-or-nothing property of an
isometric twitch contraction of skeletal muscle?- AA) equivalent calcium reuptake by the sarcoplasmic reticulum
- BB) equivalent calcium released by each action potential
- CC) equivalent activation of calmodulin stimulating myosin light-chain kinase activity
- DD) equal numbers of crossbridges activated by the calcium released
- EE) all-or-nothing property of the action potential generated by a skeletal muscle
93Which of the following is a property of isometric skeletal muscle contraction?
- AA) rapid shortening of the muscle
- BB) rapid lengthening of the muscle
- CC) load is greater than the force generated by the muscle
- DD) load is equal to the force generated by the muscle
- EE) load is less than the force generated by the muscle
94Which of the following is a property of isotonic skeletal muscle contraction?
- AA) slow increase in force with no change in muscle length
- BB) rapid increase in force with no change in muscle length
- CC) muscle length will be increased by contraction
- DD) load is greater than the force generated by the muscle
- EE) load is less than the force generated by the muscle
95Which of the following statements about excitation-contraction coupling in skeletal muscle is
FALSE?- AA) An action potential in the sarcolemma stimulates the opening of voltage-gated calcium channels in the plasma membrane and the sarcoplasmic reticulum.
- BB) Calcium binds to troponin, causing a shift in tropomyosin thereby exposing the binding sites on actin for myosin.
- CC) DHP receptors on the T tubules detect changes in voltage and communicate to ryanodine receptors on the sarcoplasmic reticulum to open calcium channels.
- DD) An end-plate potential triggers an action potential on the sarcolemma.
- EE) Calcium ATPases in the sarcoplasmic reticulum are necessary for relaxation of the muscle.
96Which of the following statements about end-plate potentials is FALSE?
- AA) They are graded potentials.
- BB) They are always depolarizations.
- CC) They are always of sufficient magnitude to generate an action potential in the
sarcolemma. - DD) They are a result of acetylcholine binding to muscarinic cholinergic receptors.
- EE) They are terminated by removal of acetylcholine from the synaptic cleft.
97Which of the following best describes an isotonic contraction?
- AA) When the contractile elements shorten, they lengthen the elastic elements but do not move the load.
- BB) When the contractile elements shorten, they create enough force to move the load.
- CC) When the contractile elements lengthen, they shorten the elastic elements and move the load.
- DD) When the contractile elements lengthen, they lengthen the elastic elements but do not move the load.
- EE) The contractile elements stay the same length as the elastic elements shorten and move the load.
98The speed with which the skeletal muscle generates force is determined primarily by
________.- AA) the amount of energy available
- BB) the type of myosin present
- CC) actin
- DD) troponin
- EE) tropomyosin
99Which of the following is the property of skeletal muscle whereby an increase in the frequency
of action potentials enhances the force developed by the muscle cell?- AA) Length-tension relationship
- BB) Summation
- CC) Force-velocity relationship
- DD) External tension
- EE) Internal tension
100The tension produced during skeletal muscle contraction can be increased by all of the
following except one. Which one is it?- AA) recruiting motor units
- BB) increasing the frequency of action potentials in the motor neuron innervating the muscle
- CC) increasing the frequency of action potentials in the muscle fiber
- DD) initiating the contraction when the muscle is at its optimum length
- EE) increasing the load on the muscle
101Which of the following statements about summation and tetanus is FALSE?
- AA) Summation and tetanus occur at high frequencies of skeletal muscle stimulation.
- BB) Summation and tetanus do NOT occur in cardiac muscle.
- CC) Summation and tetanus result from increases in cytosolic calcium levels.
- DD) Summation and tetanus result in greater tension in the muscle.
- EE) The maximum tension developed during summation and tetanus is treppe.
102Once a skeletal muscle cell begins to shorten during an isotonic twitch contraction, ________.
- AA) the amount of force generated by the muscle will continue to increase
- BB) the amount of force generated by the muscle will start to decrease
- CC) the amount of force generated by the muscle will remain constant
- DD) the muscle will continue to shorten until the force generated by the muscle stops increasing
- EE) the muscle will stop shortening once the force is greater than the load
103Which of the following conditions will result in a skeletal muscle that produces a greater
amount of force?- AA) more sarcomeres in series
- BB) more sarcomeres in parallel
- CC) fewer myofibrils per muscle cell
- DD) fewer sarcomeres in parallel
- EE) fewer sarcomeres in series
104Which of the following is NOT an accurate description of specific muscle fiber types?
- AA) Fast glycolytic fibers are the largest diameter fibers.
- BB) Slow oxidative fibers are the smallest diameter fibers.
- CC) Slow oxidative fibers are quick to fatigue.
- DD) Fast glycolytic fibers produce their ATP by glycolysis.
- EE) Fast oxidative fibers have a high mitochondrial density.
105As skeletal muscle is further stretched beyond the length where optimum force is developed,
________.- AA) the amount of calcium released by the sarcoplasmic reticulum is reduced as length increases
- BB) the thin filaments are pulled away from one another, thereby reducing their ability to interact with myosin
- CC) the thick filaments are pulled away from one another, thereby reducing their ability to interact with actin
- DD) the thick filaments overlap one another, thereby reducing their ability to interact with actin
- EE) the thin filaments overlap one another, thereby reducing their ability to interact with myosin
106As the sarcomere length of skeletal muscle is reduced beyond the length where optimum force
is developed, ________.- AA) the amount of calcium released by the sarcoplasmic reticulum is reduced as length increases
- BB) the thin filaments are pulled away from one another, thereby reducing their ability to interact with myosin
- CC) the thick filaments are pulled away from one another, thereby reducing their ability to interact with actin
- DD) the thick filaments overlap one another, thereby reducing their ability to interact with actin
- EE) the thin filaments overlap one another, thereby reducing their ability to interact with myosin
107In the body, the sarcomere length of skeletal muscle cells is usually ________.
- AA) much less than optimum length
- BB) near optimal
- CC) much greater than optimum length
- DD) quite variable from one muscle to the next
- EE) 3 microns
108Which of the following does NOT influence the force generated by an individual muscle fiber?
- AA) frequency of stimulation
- BB) fiber diameter
- CC) length at onset of contraction
- DD) recruitment
- EE) summation
109What is an increase in the number of active motor units that would increase the force
developed by a skeletal muscle called?- AA) Recruitment
- BB) Summation
- CC) Treppe
- DD) Tetanus
- EE) Length-tension relationship
110Contraction of motor units in a(n) ________ manner allows a muscle to maintain a level of
force for a duration of time without fatiguing.- AA) synchronous
- BB) asynchronous
- CC) asymmetrical
- DD) symmetrical
- EE) random
111Which of the following best describes the relationship between motor neuron size, motor unit
size, and order of recruitment?- AA) large motor neurons : small motor unit : first to be recruited
- BB) large motor neurons : small motor unit : last to be recruited
- CC) large motor neurons : large motor unit : first to be recruited
- DD) large motor neurons : large motor unit : last to be recruited
- EE) There is no relationship.
112A muscle is stimulated at a frequency that allows the muscle to relax completely between
contractions. However, the amount of tension increases with each contraction. What is this
called?- AA) twitch
- BB) summation
- CC) tetanus
- DD) recruitment
- EE) treppe
113The mechanism responsible for the size principle involves ________.
- AA) larger motor neurons that contain the greatest number of muscle cells and reach threshold easier than smaller neurons
- BB) larger sympathetic neurons that contain the greatest number of muscle cells and reach threshold easier than smaller neurons
- CC) smaller sympathetic neurons that contain the least number of muscle cells and reach threshold easier than larger neurons
- DD) smaller motor neurons that contain the least number of muscle cells and reach threshold easier than larger neurons
- EE) smaller motor neurons that contain the greatest number of muscle cells and reach threshold easier than larger neurons
114Which of the following is NOT a property of glycolytic fibers as compared to oxidative fibers?
- AA) high capacity for lactic acid production
- BB) fewer capillaries
- CC) absence of myoglobin
- DD) poor ability to produce ATP in the absence of oxygen
- EE) readily fatiguable
115What molecule present primarily within oxidative skeletal muscle cells acts as an oxygen
buffer due to its ability to bind oxygen?- AA) Hemoglobin
- BB) Myoglobin
- CC) Lactic acid
- DD) Myosin
- EE) Myosin light chain
116What causes some muscle fibers to appear red?
- AA) greater blood supply
- BB) presence of myoglobin
- CC) presence of lots of mitochondria
- DD) high concentration of actin and myosin
- EE) presence of troponin
117What is the site where a muscle attaches to a stationary bone called?
- AA) origin
- BB) insertion
- CC) abductor
- DD) adductor
- EE) flexor
118What connects muscles to bone?
- AA) ligaments
- BB) tendons
- CC) cartilage
- DD) capillaries
- EE) T tubules
119Relative to the triceps muscle, the biceps is its ________.
- AA) origin
- BB) insertion
- CC) agonist
- DD) antagonist
- EE) abductor
120What type of receptor detects muscle length?
- AA) DHP
- BB) ryanodine
- CC) muscle spindle
- DD) Golgi tendon organ
- EE) nociceptor
121What is an annulospiral ending?
- AA) a structure in the cochlea that contains hair cells
- BB) sensory endings in the muscle spindle that detect muscle length
- CC) sensory endings in the Golgi tendon organ that detect muscle tension
- DD) a structure in the semicircular canals that contains hair cells
- EE) a structure in the utricle that contains hair cells
122What type of efferent neuron innervates intrafusal muscle fibers?
- AA) type Ia
- BB) type Ib
- CC) type II
- DD) alpha motor neurons
- EE) gamma motor neurons
123Which of the following statements is TRUE regarding activation of alpha and gamma motor
neurons?- AA) Alpha and gamma motor neurons are activated at the same time.
- BB) Alpha motor neurons are activated before gamma motor neurons.
- CC) Gamma motor neurons are activated before alpha motor neurons.
- DD) During light activity, alpha motor neurons are activated first; during heavy activity, gamma motor neurons are activated first.
- EE) During light activity, gamma motor neurons are activated first; during heavy activity, alpha motor neurons are activated first.
124Which of the following is the correct order of muscle fiber recruitment from first to last?
- AA) slow oxidative : fast oxidative : fast glycolytic
- BB) fast oxidative : fast glycolytic : slow oxidative
- CC) fast glycolytic : fast oxidative : slow oxidative
- DD) slow oxidative : fast glycolytic : fast oxidative
- EE) fast glycolytic : slow oxidative : fast oxidative
125Which of the following muscle types has the slowest contraction time?
- AA) fast glycolytic skeletal muscle
- BB) fast oxidative skeletal muscle
- CC) slow oxidative skeletal muscle
- DD) smooth muscle
- EE) cardiac muscle
126Which of the mechanisms listed below does NOT account for the decrease in force
development by muscle cells during sustained force development?- AA) Compression of muscle during contraction can reduce blood flow to the muscle.
- BB) Repeated action potentials along the same neuron can lead to neuromuscular fatigue.
- CC) The crossbridges can become resistant to ATP.
- DD) Oxidative fibers can be depleted of glycogen, their primary energy source.
- EE) Glycolytic fibers produce lactic acid and inhibit enzyme activity with their hydrogen ion.
127Which of the following is NOT an adaptation of skeletal muscle that would be observed in
response to aerobic training?- AA) an increase in mitochondrial density
- BB) an increase in capillary density
- CC) an increase in the number of oxidative fibers
- DD) an increase in the diameter of the skeletal muscle fibers
- EE) an increase in the concentration of oxidative enzymes
128Where are gap junctions commonly found?
- AA) single-unit smooth muscle only
- BB) multi-unit smooth muscle only
- CC) cardiac muscle only
- DD) both single-unit smooth muscle and cardiac muscle
- EE) both single-unit and multi-unit smooth muscle
129Which of the following is true of ALL muscle types?
- AA) contract by using the sliding filament mechanism and cross-bridge cycling
- BB) are striated
- CC) contain T tubules
- DD) contain calmodulin
- EE) recruitment increases the strength of contraction
130In smooth muscle, calcium triggers contraction by binding to what protein?
- AA) troponin
- BB) myosin light chain kinase
- CC) myosin light chain
- DD) calmodulin
- EE) DHP receptors
131Calcium binding to calmodulin causes phosphorylation of what protein in what type of
muscle?- AA) troponin in skeletal and cardiac muscle only
- BB) troponin in smooth muscle only
- CC) actin in cardiac and smooth muscle
- DD) actin in smooth muscle only
- EE) myosin in smooth muscle only
132Which of the following adaptations does NOT generally occur with aerobic exercise?
- AA) an increase in the number of mitochondria per muscle fiber
- BB) an increase in the number of myofibrils per muscle fiber
- CC) a conversion of fast glycolytic fibers to fast oxidative fibers
- DD) an increase in the blood supply to the muscles
- EE) an increase in the aerobic capacity of muscle
133The interaction between actin and myosin in smooth muscle requires ________.
- AA) the interaction between calcium and troponin to expose the myosin binding site on the actin molecule
- BB) that the calcium-calmodulin complex activates myosin light-chain kinase, which phosphorylates myosin light chain thereby allowing myosin to bind with actin
- CC) the tropomyosin must be moved out of the way by troponin before myosin can bind to actin
- DD) the activation of troponin, which stimulates myosin light-chain kinase to phosphorylate myosin light chain, allowing myosin to bind with actin
- EE) that the calcium-calmodulin complex directly phosphorylates myosin light chain, allowing myosin to bind to actin
134What is the source of variability in the response of smooth muscle cells from different organs
to autonomic nervous activity (some relax to sympathetic nervous output while others
contract)?- AA) the amount of neurotransmitter released into the synaptic cleft
- BB) the duration of neurotransmitter release from the autonomic neurons
- CC) the neurotransmitter released by the autonomic nervous system
- DD) the type of receptor present on the effector organ
- EE) the presynaptic modulation of the autonomic neurons
135Which of the following could cause a pacemaker potential?
- AA) spontaneous opening of sodium channels
- BB) spontaneous opening of potassium channels
- CC) spontaneous closing of calcium channels
- DD) spontaneous opening of chloride channels
- EE) All of the above
136Skeletal muscle fibers are formed by the fusion of multiple cells during embryonic
development, resulting in the presence of numerous nuclei per fiber.- ARichtig
- BFalsch
137Thick filaments have many protrusions along their middle (head of the myosin filaments) but
none at their ends.- ARichtig
- BFalsch
138Skeletal muscle and cardiac muscle are multinucleated cells, whereas smooth muscle cells each
have one nucleus.- ARichtig
- BFalsch
139As skeletal muscle shortens with contraction, the length of the I band remains constant as the
length of the A band decreases- ARichtig
- BFalsch
140Binding of ATP to myosin increases myosinʹs affinity for actin.
- ARichtig
- BFalsch
141A skeletal muscle cell produces force for only a small portion of its contractile cycle because
only a small portion of the crossbridge cycle involves force generation.- ARichtig
- BFalsch
142The proximity of the sarcoplasmic reticulum to each sarcomere permits the nearly
simultaneous delivery of calcium to all sarcomeres of the muscle fiber.- ARichtig
- BFalsch
143The primary source of calcium that drives skeletal muscle contraction is the sarcoplasmic
reticulum.- ARichtig
- BFalsch
144Ryanodine receptors are calcium channels in the sarcoplasmic reticulum.
- ARichtig
- BFalsch
145Creatine phosphate provides an immediate source of high energy phosphate to donate to ADP
at the onset of muscle activity.- ARichtig
- BFalsch
146The contraction phase of a twitch lasts longer than the relaxation phase.
- ARichtig
- BFalsch
147Skeletal muscle fibers operate at near-optimal sarcomere length in situ.
- ARichtig
- BFalsch
148The velocity of shortening during an isometric contraction is zero.
- ARichtig
- BFalsch
149The velocity of shortening of a muscle is greatest when there is no load on the muscle.
- ARichtig
- BFalsch
150Intrafusal muscle fibers contribute directly to the tension produced during muscle contraction.
- ARichtig
- BFalsch
151Alpha motor neurons innervate extrafusal muscle fibers.
- ARichtig
- BFalsch
152The biceps cause flexion of the arm, whereas the triceps cause extension.
- ARichtig
- BFalsch
153Activation of Golgi tendon organs during overstretching of a muscle protects the muscle by
inhibiting its contraction.- ARichtig
- BFalsch
154A skeletal muscle with slower ATPase activity can complete more crossbridge cycles per
second.- ARichtig
- BFalsch
155There are no slow glycolytic fibers.
- ARichtig
- BFalsch
156Hemoglobin in skeletal muscle acts as an oxygen buffer.
- ARichtig
- BFalsch
157Contraction of smooth muscle cells is driven by binding of calcium to calmodulin.
- ARichtig
- BFalsch
158Smooth and cardiac muscle are innervated by the autonomic nervous system, whereas skeletal
muscle is innervated by the somatic nervous system.- ARichtig
- BFalsch
159The speed with which smooth muscle cells contract is similar to fast glycolytic skeletal muscle
cells.- ARichtig
- BFalsch
160Spontaneous depolarization of smooth muscle cells is mediated by pacemaker cells
- ARichtig
- BFalsch
161Slow-wave potentials are caused by cyclical fluctuations in opening and closing of potassium
channels.- ARichtig
- BFalsch
162Action potentials in cardiac muscle last longer than action potentials in skeletal muscle.
- ARichtig
- BFalsch
163Pacemaker activity occurs in certain smooth muscle cells and cardiac muscle cells.
- ARichtig
- BFalsch
164There is no summation of cardiac muscle.
- ARichtig
- BFalsch
165Oxidative phosphorylation is the primary energy source for cardiac muscle.
- ARichtig
- BFalsch
Informationen
- Beschreibung
- Quiz am Human Phys Mid 2, erstellt von Arani Mahes am 05/11/2019.
- Autor
- Arani Mahes
- Sprache
- English
- Aufrufe
- 14
- Bewertung
- Noch keine Bewertungen Bewerte dieses Quiz