1a. Which of the following accurately describes difference(s) between graded pot
ID: 3480291 • Letter: 1
Question
1a. Which of the following accurately describes difference(s) between graded potentials and action potentials?
A. Graded potentials are for short-distance communication only, whereas action potentials are for short- and long-distance communication
B. Graded potentials are transmitted through electrical synapses, whereas action potentials are transmitted through chemical synapses
C. Graded potentials may be caused by the opening of ligand-gated Cl- channels, whereas action potentials may be caused by the opening of K+ leakage channels
D. Both A and B
E. A, B, and C
1b. Which of the following would occur after baroreceptors detected a moderate drop in blood pressure (a deviation from homeostasis)?
A.The cardiovascular center would increase parasympthetic stimulation to the heart
B.The cardiovascular center would decrease sympathetic stimulation to vasomotor nerves
C. Systemic tissues would begin to generate more CO2
D.The cardiovascular center would decrease sympathetic stimulation to the heart
E.None of the above. They are not mechanisms for reversing a drop in blood pressure.
1c.Which of the following substances generally cannot move out of a systemic capillary (continuous or fenestrated capillary)?
A.plasma proteins like fibrinogen and albumin
B.carbon dioxide
C.glucose
D.amino acids
E.None of the above. They may all freely pass out of a systemic capillary.
Explanation / Answer
1a) Graded potentials can be depolarising or hyperpolarising. But, the action potential is always depolarising. In graded potential, the amplitude is proportional to the strength of the stimulus whereas in action potential, the amplitude follows all or none law. Therefore, graded potential is useful only for short distance communication while action potential can be used for long distance communication. In graded potential, sodium, potassium and chloride ions are involved, but in action potential only sodium and potassium ions are involved. Graded potentials are transmitted through electrical synapses, whereas action potentials are transmitted through chemical synapses. Therefore, the answer for this question is option E.
1b) When baroreceptors detect a moderate drop in blood pressure, the cardiovascular center would decrease the amount of parasympathetic stimulation and increase the amount of sympathetic stimulation to the heart. Therefore, the answer for this question is option E.
1c) Oxygen, carbondioxide, glucose, amino acids, hormones etc. move freely across the systemic capillary by simple diffusion. Larger molecules like fibrinogen and albumin usually will not move out of the systemic capillaries because of their larger size.
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