The sinoatrial node is the heart's normal pacemaker because
a. it has the fastest natural rate of autorhythmicity.
b. it has both sympathetic and parasympathetic innervation.
c. it lies in the right atrium.
d. activation of K+ channels occurs more rapidly in this region than elsewhere in the heart.
e. none of these answers.
A
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Answer the following statements true (T) or false (F)
1. Dopamine and serotonin are neurotransmitters that can act as natural pain killers. 2. The brainstem consists of the medulla oblongata, the pons, and the midbrain. 3. Many of the “vital centers” are located in the brainstem. 4. The hypothalamus is important in regulation of body temperature. 5. The hypothalamus secretes ADH into the blood to help control water balance.
Adjacent to the lumen, the innermost tissue layer of the GI tract is the __________.
Fill in the blank(s) with the appropriate word(s).
Severe ________________________________________ is the most significant clinical sign of Salmonella
Fill in the blank(s) with correct word
Which of the following are released by damaged tissues and function as intercellular autocrine or paracrine signals?
A. Erythropoietin B. Prostaglandins C. Epinephrine D. Norepinephrine E. Aldosterone