Ch 9: The Circulatory, Lymphatic, and Immune Systems (Princeton Review) Flashcards
(111 cards)
What are the very first branches from the aorta?
the coronary arteries
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What is the only deoxygenated blood that does not end up in the vena cavae?
blood in the coronary sinus; instead, the coronary sinus drains directly into the right atrium
p. 331
At the end of systole when the ventricles stop contracting, blood begins to flow backward from the aorta into the left ventricle, but very little backflow actually occurs, because the semilunar valves slam shut when the pressure in the ventricles becomes…
….lower than the pressure in the great arteries.
p. 333
What is another term for the mitral valve?
the bicuspid valve
What is a syncytium?
a tissue in which the cytoplasm of different cells can communicate via gap junctions
p. 334
In cardiac muscle, the gap junctions are found in the ____________ ______, the connections between cardiac muscle cells.
intercalated disks
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Voltage-gated sodium channels, also called ____ ______ channels, play an important role in cardiac muscle, as in neurons, but, in addition, another type of voltage-gated channel, the ____ _______ channel, is involved in the cardiac muscle action potential.
fast sodium
slow calcium
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To maximize the entry of calcium in the cell, cardiac muscle has involutions of the membrane called _ _______. The action potentials travel down along T tubules, allow the entry of calcium from the extracellular environment, and induce the _______ _______ to release calcium.
T tubules
sarcoplasmic reticulum
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Cardiac muscle action potentials last much (longer/shorter) than neuronal or skeletal muscle action potentials, and will therefore have a (longer/shorter) absolute refractory period.
longer
longer
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Is the strength of contraction by cardiac muscle affected by the extracellular concentration of calcium ions?
Yes, a significant portion of the calcium that stimulates contraction comes from the extra cellular pool, entering the cell as part of the action potential.
The affinity of hemoglobin for oxygen is influenced by…
…temperature, carbon dioxide levels, and pH.
(from Khan Academy https://www.khanacademy.org/test-prep/mcat/biological-sciences-practice/biological-sciences-practice-tut/e/circulatory-system—passage-2?_ga=2.12146039.2119758222.1652986581-826931683.1648912754)
Over which blood vessel is the drop in blood pressure the greatest?
arterioles
(https://www.khanacademy.org/test-prep/mcat/biological-sciences-practice/biological-sciences-practice-tut/e/circulatory-system—passage-2?_ga=2.12146039.2119758222.1652986581-826931683.1648912754)
Which types of muscle are striated?
Which are not?
cardiac and skeletal muscle
smooth muscle is not
What is the difference between serum and plasma?
They are the same EXCEPT the serum excludes the fibrinogen and other clotting factors.
What is plasma made up of?
90% water
8% proteins (albumin, antibodies, fibrinogen, lipoproteins)
2% hormones, electrolytes, nutrients, glucose
[From Khan Academy video: “What’s Inside of Blood?”]
State the Bohr effect simply.
How about more complex?
CO2 and H+ affect the affinity of hemoglobin for oxygen.
Stated not simply:
The Bohr effect describes hemoglobin’s lower affinity for oxygen secondary to increases in the partial pressure of carbon dioxide and/or decreased blood pH. This lower affinity, in turn, enhances the unloading of oxygen into tissues to meet the oxygen demand of the tissue.
State the Bohr vs Haldane effect
The Bohr Effect is a decreased affinity of Hb for O2 when the concentration of CO2/H+ is high.
The Haldane Effect is a decreased affinity of Hb for CO2/H+ when the concentration of O2 is high.
The SA node exhibits automaticity and its action potential is commonly divided into 3 separate phases. Name them.
Why is this different from other cardiac myocytes?
Phase 0, phase 3, and phase 4
(other cardiac myocytes have phases 1 and 2, but the SA node does not)
Skeletal muscle cells and other myocytes depolarize because of a ___ ______, not __ like the SA node.
Na+ influx
Ca2+
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Why don’t potassium leak channels cause spontaneous action potential in neurons are muscle cells?
Potassium leak channels allow potassium to leave the cell, down a gradient, polarizing the membrane.
In contrast, sodium is at a higher concentration outside of the cell, so sodium leak channels allow sodium to enter the cell and depolarize the membrane.
p. 336
The cardiac muscle cells of the heart have a resting membrane potential of about ___ __, very close to the K+ equilibrium potential.
- 90 mV
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Why do cardiac muscle cells have a plateau phase (phase 2) in their membrane potential?
Because during this phase, the influx of Ca2+ ions balances the K+ efflux from phase 1.
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What happens during phase 0 of the membrane potential in cardiac muscle cell?
fast Na+ channels open
Na+ influx
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What happens during phase 1 of the membrane potential in cardiac muscle cell?
(Note: all ion movement is through voltage-gated channels; all channels open and close at the beginning of the phase.)
Na+ channels inactivate
K+ channels open
K+ efflux
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