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Nursing Physiology
Test 4
100
Physiology
Undergraduate 2
04/23/2013

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Term
1) Skeletal muscle fibers are formed by the fusion of multiple cells during embryonic development, resulting in the presence of numerous nuclei per fiber.
Definition
true
Term
2) Thick filaments have many protrusions along their middle (head of the myosin filaments) but none at their ends.
Definition
false
Term
3) Skeletal muscle and cardiac muscle are multinucleated cells, whereas smooth muscle cells each have one nucleus.
Definition
false
Term
4) As skeletal muscle shortens with contraction, the length of the I band remains constant as the length of the A band decreases.
Definition
false
Term
5) Binding of ATP to myosin increases myosin's affinity for actin.
Definition
false
Term
6) The contractile portion of the thin filament is composed of what protein?
Definition
actin
Term
7) What is the protein component of the thin filament that binds to calcium thereby initiating skeletal muscle contraction?
Definition
troponin
Term
8) Which of the following is a structural protein that extends along each thick filament from M line to Z line.
Definition
Titin
Term
9) The shortening of a skeletal muscle fiber during contraction involves which of the following?
Definition
the sarcomeres shortening
Term
10) During skeletal muscle contraction, as the muscle shortens, the thick and thin filaments ________.
Definition
slide past one another
Term
11) When 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 ________.
Definition
titin acting as a spring using the energy stored by the stretching
Term
12) The repeated, oscillating interaction between actin and myosin that results in the generation of force by a skeletal muscle cell is called what?
Definition
crossbridge cycling
Term
13) What converts the myosin head into the high-energy state?
Definition
the hydrolysis of ATP
Term
14) The release of an inorganic phosphate from the myosin molecule directly results in which of the following?
Definition
power stroke
Term
15) In order for crossbridge cycling to occur, the actin-myosin complex must be broken by which of the following?
Definition
binding of ATP to myosin
Term
16) The sequence of events that links the action potential to changes in skeletal muscle force development is called what?
Definition
excitation-contraction coupling
Term
17) During skeletal muscle contraction, multiple crossbridge cycles are occurring between the same thick and thin filament. Which of the following best describes this process?
Definition
Crossbridge cycling is asynchronous between a certain thick and thin filament.
Term
18) Contraction of skeletal muscle fibers is stimulated by what type of neuron?
Definition
motor neurons
Term
19) Which of the following is NOT a specialization observed at the neuromuscular junction?
Definition
Each muscle fiber is innervated by multiple motor neurons.
Term
20) Increases 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.
Definition
dihydropyridine receptor : ryanodine receptor
Term
21) Which of the following is the voltage sensor that initiates an increase in cytoplasmic calcium in response to an action potential?
Definition
dihydropyridine receptor
Term
22) The binding of calcium to troponin will directly cause which of the following?
Definition
the movement of tropomyosin, thereby exposing the myosin-binding site on the actin molecule
Term
23) What portion of a sarcomere shows up as light striations when viewed under a microscope?
Definition
I band
Term
24) Which of the following best describes the function of transverse (t) tubules and the sarcoplasmic reticulum in skeletal muscle contraction?
Definition
C) 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.
Term
25) During the cross-bridge cycle, ATP binding to myosin causes which of the following?
Definition
the myosin head to detach from actin
Term
26) Prolapse involves improper alignment of the atrioventricular valve such that one or more of the cusps are pushed into the atrium by the pressure developed in the ventricle.
Definition
true
Term
27) The contractile cycle of the heart normally originates from a pacemaker cell within the sinoatrial node.
Definition
true
Term
28) Action potentials travel more quickly through the ventricular contractile cells than the conduction pathway.
Definition
false
Term
29) Ventricular contraction begins at the top of the heart and travels downward to its apex.
Definition
false
Term
30) The AV node autorhythmic cells are the fastest depolarizing cells in the heart.
Definition
false
Term
31) Which of the following statements about the plateau phase of a contractile cell action potential is FALSE?
Definition
The membrane potential remains the same as the peak of the action potential for about 200 milliseconds.
Term
32) During phase 3 of a contractile cell action potential, ________.
Definition
only potassium permeability is increased
Term
33) Which of the following ion channels does NOT participate in the contractile cell action potential?
Definition
type T calcium channels
Term
34) Which of the following is NOT a part of the excitation-contraction coupling in cardiac muscle?
Definition
Calcium binds to calmodulin in the cytosol.
Term
35) What is the function of the sodium-calcium exchanger in cardiac muscle?
Definition
remove calcium from the cytosol by transporting it to the extracellular fluid
Term
36) What is the role of ryanodine receptors in cardiac muscle?
Definition
They release calcium from the sarcoplasmic reticulum.
Term
37) Which of the following components of an ECG represents ventricular depolarization?
Definition
QRS complex
Term
38) Which of the following components of an ECG represents ventricular repolarization?
Definition
T wave
Term
39) If damage to the AV node slowed down conduction through this tissue, what would be observed on an ECG?
Definition
a longer PR interval
Term
40) In an ECG recording, the RR interval is 0.5 seconds. What is the heart rate?
Definition
120 beats/min
Term
41) Which of the following describes second degree heart block?
Definition
not every atrial contraction is followed by a ventricular contraction
Term
42) During isovolumetric relaxation, ________.
Definition
the AV and semilunar valves are closed and ventricular pressure is decreasing
Term
43) What is occurring during ventricular ejection?
Definition
the AV valves are closed and the semilunar valves are open as blood is leaving the ventricles
Term
44) Which of the following is TRUE of the ventricular filling phase of the cardiac cycle?
Definition
Ventricular pressure is less than aortic pressure.
Term
45) What phase of the cardiac cycle is the heart in when all four valves of the heart are closed and ventricular pressure is less than atrial pressure?
Definition
none
Term
46) What phase of the cardiac cycle is the heart in when all four valves of the heart are open and ventricular pressure is less than atrial pressure?
Definition
none
Term
47) During which phase of the cardiac cycle are all four heart valves open?
Definition
none
Term
48) Ejection of blood from the right ventricle will continue until ________.
Definition
pressure in the pulmonary artery is greater than pressure in the right ventricle
Term
49) The increase in ventricular volume early in diastole reflects ________.
Definition
the passive movement of blood through the atrium and into the ventricle
Term
50) The small increase in ventricular pressure observed late in diastole is caused by ________.
Definition
atrial contraction
Term
51) The portion of osmotic pressure exerted by ________ in the blood is known as colloid osmotic pressure.
Definition
proteins
Term
52) Under normal conditions, which Starling forces favor filtration?
Definition
capillary hydrostatic pressure and interstitial fluid osmotic pressure
Term
53) Which of the following inaccurately represents normal forces across capillary walls?
Definition
Interstitial fluid hydrostatic pressure increases from arteriole end to venous end.
Term
54) Given that the net filtration of fluid out of the capillaries averages about 3 liters per day, how is blood volume maintained in light of this apparent fluid loss?
Definition
The lymphatic system returns filtered fluid is returned to the blood.
Term
55) Which of the following is NOT a mechanism that alters the balance between filtration and absorption in the body?
Definition
increasing hydrostatic pressure gradient in cases of enhanced interstitial protein
Term
56) Which of the following comparisons between systemic capillaries and lymphatic capillaries is true?
Definition
Net filtration occurs across systemic capillaries; net absorption occurs across lymphatic capillaries.
Term
57) Foreign materials are filtered out of the lymphatic fluid by what type of cell located within the lymph nodes?
Definition
macrophages
Term
58) Exchange between blood and interstitial fluid occurs across capillaries and, to a lesser extent, ________.
Definition
venules
Term
59) What region of the cardiovascular system contains valves?
Definition
both the heart and veins
Term
60) Veins functions as ________ reservoirs due to their ________ compliance.
Definition
volume : high
Term
61) Valves, which are ________, maintain the unidirectional movement of blood, thereby facilitating the return of blood to the heart.
Definition
found only in peripheral veins
Term
62) The high compliance of veins allows them to ________.
Definition
accommodate large volumes of blood with little change in pressure
Term
63) At rest, the greatest proportion of blood volume is present within the ________.
Definition
systemic veins
Term
64) Which of the following would decrease central venous pressure?
Definition
standing up
Term
65) An increase in the volume of blood ejected from the heart, with no change in total peripheral resistance, would ________.
Definition
elevate mean arterial pressure
Term
66) An increase in total peripheral resistance, in the absence of any change in cardiac output, would ________.
Definition
elevate mean arterial pressure
Term
67) The respiratory pump facilitates the return of blood to the heart by ________.
Definition
raising the pressure gradient between abdominal and thoracic veins during inspiration
Term
68) Which of the following would NOT increase mean arterial pressure?
Definition
decreased parasympathetic activity to the arterioles
Term
69) The long-term regulation of arterial blood pressure involves ________.
Definition
the control of blood volume by the kidneys
Term
70) ________ are responsible for the detection of mean arterial pressure.
Definition
Arterial baroreceptors
Term
71) The distribution of cardiac output to each organ is determined by the relative resistance of that organ's vascular bed compared with all other organs.
Definition
true
Term
72) An increase in blood flow to metabolically active tissue is called reactive hyperemia.
Definition
false
Term
73) Intrinsic regulation of arteriolar radius regulates mean arterial pressure.
Definition
false
Term
74) Flow autoregulation refers to an organ's ability to maintain perfusion pressure in the presence of a range of blood flows.
Definition
false
Term
75) Histamine induces vasodilation by stimulating the synthesis of nitric oxide.
Definition
true
Term
76) Collagen activates factor X.
Definition
false
Term
77) A fibrin clot can occur in the absence of platelet aggregation.
Definition
false
Term
78) Coagulation factors continuously circulate in the blood in their inactive form.
Definition
true
Term
79) Calcium is required for formation of a blood clot.
Definition
true
Term
80) Vitamin K is necessary for blood clot formation because it activates the extrinsic pathway.
Definition
false
Term
81) Protein C inhibits both the intrinsic and extrinsic clotting pathways.
Definition
true
Term
82) What is a hematocrit measuring?
Definition
the percentage of blood that is comprised of red blood cells
Term
83) A normal hematocrit is approximately what value?
Definition
45
Term
84) Which of the following is NOT a protein found in plasma?
Definition
carbonic anhydrase
Term
85) What is the most abundant plasma protein?
Definition
albumin
Term
86) A majority of the protein present within blood is synthesized within what organ?
Definition
liver
Term
87) Which of the following statements is NOT accurate with respect to erythrocytes?
Definition
They migrate into infected regions of tissue.
Term
88) Which of the following proteins is located inside erythrocytes?
Definition
hemoglobin, spectrin, and carbonic anhydrase
Term
89) The iron-containing ring in hemoglobin is called ________ and it binds ________.
Definition
heme : oxygen
Term
90) What enzyme catalyzes the conversion of carbon dioxide and water to carbonic acid, and where is this enzyme located?
Definition
carbonic anhydrase : erythrocytes
Term
91) Carbonic acid reversibly dissociates to form what two products, without the need of an enzyme?
Definition
bicarbonate and hydrogen ion
Term
92) Erythrocytes are synthesized in what organ and under the control of what chemical?
Definition
bone marrow : erythropoietin
Term
93) What hematopoietic growth factor controls red blood cell synthesis, and what organ releases it?
Definition
erythropoietin : kidney
Term
94) What triggers erythropoietin release?
Definition
decreased blood oxygen levels
Term
95) Pernicious anemia is associated with which of the following?
Definition
insufficient vitamin B12
Term
96) Old red blood cells are removed from the blood by macrophages in what organ?
Definition
spleen
Term
97) During hemoglobin metabolism, what is the yellow pigmented substance produced by the removal of the iron group called?
Definition
bilirubin
Term
98) Iron is transported in blood bound to what molecule?
Definition
transferrin
Term
99) What organ can store iron as transferrin?
Definition
none
Term
100) What is the most abundant class of white blood cells?
Definition
neutrophils
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