問題一覧
1
58. Ions flow across gap junctions to cause early threshold
a
2
What is the first step in an action potential within an contractile cell.
Contractile cells start with a resting membrane potential of about -90'mV. Neighboring cells (either autorhythmic or contractile cells) depolarize. Gap junctions are open and positive ions (Ca*2 and Na*) move in to the contractile cells through gap junctions and trigger a threshold.
3
52. Na+ leak Channels
a
4
51. K+ Channels open
e
5
29.)
fast na++ channel
6
12. Repolarization (autorhythmic cells)
c
7
55. Repolarization
e
8
What is the first step in an action potential within an autorhythmic cell.
Autorhythmic cell starts out at resting membrane potential (--60 mV), positive out, negative in. Cell begins depolarizing due to a slow continuous influx of sodium When the membrane potential gets to -40 millivolts, it has reached threshold for initiating an action potential.
9
16.) pacemaker potential (autorhythmic)
due to influx of sodium
10
61. Depolarization
b
11
72. Atrial systole begins: atrial contraction forces a small amount of additional blood into relaxed ventricles
a
12
63. Repolarization
d
13
31.)
k+ channel
14
73. Ventricular diastole- early: As ventricles relax, pressure in ventricles drops; blood flows back against cusps of semilunar valves and forces them closed. Blood flows into relaxed atria
d
15
23.)
Na+ leak channel
16
54. Depolarization
c
17
70. Ventricular systole- second phase: As ventricular pressure rises and exceeds pressure in the arteries the semilunar valves open and blood is ejected
c
18
26.)
Phospholipid membrane
19
57. Ca++ channels and potassium channels both open
c
20
What is the last step in an action potential within an contractile cell.
The calcium channels close while more potassium channels open, allowing potassium to quickly leave the cell, resulting in repolarization.
21
56. Reversal of membrane potential
d
22
59. K+ channels stay open
d
23
82. Which chemical is partially responsible for Erythrocyte development?
EPO
24
25.)
k+ channel
25
71. Ventricular diastole- late: All chambers are relaxed; Ventricles fill passively
e
26
11. Plateau
a
27
74. Ventricular systole- first phase: Ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves.
b
28
53. Pacemaker potential
a
29
50.) Fast CA++ channels open
d
30
27.)
gap junction
31
10. Depolarization
c
32
13. Pacemaker Potential (autorhythmic cells)
a
33
60. Fast Na+ channels open
b
34
Initiates the depolarization impulse that generates an action potential, setting the overall pace of the heartbeat.
sa node
35
The amount of Erythrocytes found in the blood is known as its
Hematocrit
36
32.)
Sarcoplasmic reticulum
37
What is the 2nd step in an action potential within an autorhythmic cell.
Calcium channels open and positively-charged calcium ions rush in. Calcium influx produces the rapidly rising phase of the action potential (depolarization), which results in the reversal of membrane potential from negative to positive inside the cell. Depolarization peaks at about +10 mV.
38
62. Plateau
c
39
14. Depolarization and reversal of the membrane potential (autorhythmic)
b
40
28.)
gap junction
41
Which type of cell fragments and becomes platelets?
B. Megakaryocyte
42
15. Repolarization (event in autorhythmic cell)
due to efflux of potassium
43
30.)
slow ca++ channel
44
What is the 2nd step in an action potential within an contractile cell.
The entry of positive ions brings the membrane potential to threshold, triggering voltage-gated channels and initiates depolarization. Rapid influx of sodium results in depolarization, resulting in a reversal of charge (depolarization) (to about +25 mV) as sodium moves into the cell.
45
What is the 3rd step in an action potential within an contractile cell.
Depolarization also causes opening of slow calcium channels, allowing calcium entry from the extracellular space. This calcium influx triggers additional calcium release from the sarcomplasmic reticulum. Intracellular calcium initiates cell contraction.
46
17.) Depolarization and reversal of the membrane potential (autorhythmic cells event)
due to influx of calcium
47
75. Isovolumetric contraction
b
48
9. Repolarization
b
49
80. The plasma of the blood is mostly made of what molecule?
water
50
What is the 3rd step in an action potential within an autorhythmic cell.
Membrane potential goes from +10 mV to resting membrane potential (-60 mV). Potassium channels open, resulting in potassium rapidly leaving the cell.
51
24.)
fast ca++ channels
52
Which part of the hemoglobin molecule does the O, bond to?
Fe * from the Heme group
53
76. Isovolumetric relaxation
d