Why is it important for impulses from the atria to be delayed at the AV node before they pass into the ventricles?
What will be an ideal response?
If the impulses from the atria were not delayed at the AV node, they would be conducted through the ventricles so quickly by the bundle branches and Purkinje cells that the ventricles would begin contracting before the atria had finished contracting. As a result, the ventricles would not be as full of blood as they could be, and the pumping action of the heart would be less efficient.
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If the peripheral capillary beds become constricted,
A) blood flow into the efferent arteriole will increase. B) blood pressure in the renal arteries will increase. C) GFR will decrease. D) vasodilation of the efferent arteriole will occur. E) the sensation of thirst will be inhibited.
Which two glands are especially noted for regressing after childhood?
A. The thymus and pineal gland B. The anterior and posterior pituitary C. The thymus and thyroid D. The thymus and adrenal medulla E. The thyroid and parathyroids
Which of the following are commonly used to produce ATP during skeletal muscle contraction?
a) creatine phosphate b) anaerobic cellular respiration c) aerobic cellular respiration d) All of these choices are correct. e) None of these choices are correct.
Define excitatory postsynaptic potential (EPSP) and inhibitory postsynaptic potential (IPSP)
A) An excitatory postsynaptic potential is a graded hyperpolarization by the postsynaptic cell and an inhibitory postsynaptic potential is a graded repolarization by the postsynaptic cell. B) An excitatory postsynaptic potential is a graded repolarization by the postsynaptic cell and an inhibitory postsynaptic potential is a graded hyperpolarization by the postsynaptic cell. C) An excitatory postsynaptic potential is a graded hyperpolarization by the postsynaptic cell and an inhibitory postsynaptic potential is a graded depolarization by the postsynaptic cell. D) An excitatory postsynaptic potential is a graded depolarization by the postsynaptic cell and an inhibitory postsynaptic potential is a graded hyperpolarization by the postsynaptic cell. E) An excitatory postsynaptic potential is a graded depolarization by the postsynaptic cell and an inhibitory postsynaptic potential is a graded repolarization by the postsynaptic cell.