問題一覧
1
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.
2
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.
3
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.
4
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.
5
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.
6
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.
7
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.
8
9. Repolarization
b
9
10. Depolarization
c
10
11. Plateau
a
11
12. Repolarization (autorhythmic cells)
c
12
13. Pacemaker Potential (autorhythmic cells)
a
13
14. Depolarization and reversal of the membrane potential (autorhythmic)
b
14
15. Repolarization (event in autorhythmic cell)
due to efflux of potassium
15
16.) pacemaker potential (autorhythmic)
due to influx of sodium
16
17.) Depolarization and reversal of the membrane potential (autorhythmic cells event)
due to influx of calcium
17
23.)
Na+ leak channel
18
24.)
fast ca++ channels
19
25.)
k+ channel
20
26.)
Phospholipid membrane
21
27.)
gap junction
22
28.)
gap junction
23
29.)
fast na++ channel
24
30.)
slow ca++ channel
25
31.)
k+ channel
26
32.)
Sarcoplasmic reticulum
27
Initiates the depolarization impulse that generates an action potential, setting the overall pace of the heartbeat.
sa node
28
50.) Fast CA++ channels open
d
29
51. K+ Channels open
e
30
52. Na+ leak Channels
a
31
53. Pacemaker potential
a
32
54. Depolarization
c
33
55. Repolarization
e
34
56. Reversal of membrane potential
d
35
57. Ca++ channels and potassium channels both open
c
36
58. Ions flow across gap junctions to cause early threshold
a
37
59. K+ channels stay open
d
38
60. Fast Na+ channels open
b
39
61. Depolarization
b
40
62. Plateau
c
41
63. Repolarization
d
42
70. Ventricular systole- second phase: As ventricular pressure rises and exceeds pressure in the arteries the semilunar valves open and blood is ejected
c
43
71. Ventricular diastole- late: All chambers are relaxed; Ventricles fill passively
e
44
72. Atrial systole begins: atrial contraction forces a small amount of additional blood into relaxed ventricles
a
45
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
46
74. Ventricular systole- first phase: Ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves.
b
47
75. Isovolumetric contraction
b
48
76. Isovolumetric relaxation
d
49
80. The plasma of the blood is mostly made of what molecule?
water
50
Which part of the hemoglobin molecule does the O, bond to?
Fe * from the Heme group
51
The amount of Erythrocytes found in the blood is known as its
Hematocrit
52
82. Which chemical is partially responsible for Erythrocyte development?
EPO
53
Which type of cell fragments and becomes platelets?
B. Megakaryocyte