An autorhythmic heart cell is one in which
A. action potentials fire spontaneoulsy.
B. action potentials are stimulated by internal stores of acetylcholine.
C. action potentials always occur at exactly the same frequency.
D. all filaments contract and relax with a high degree of synchrony.
E. action potentials are initiated by the autonomic nervous system.
A
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Platelets
A. play a role in preventing blood loss. B. are actually fragments of cells. C. can become sticky when exposed to connective tissue D. are also known as thrombocytes. E. All of the choices are correct.
A tissue has the following characteristics: free surface, single layer of cells, cells are narrow and tall, microvilli, many mitochondria, goblet cells. Which of the following is most consistent with those observations?(1) Active transport(2) Epithelium(3) Simple epithelium(4) Columnar epithelium(5) Cuboidal epithelium(6) Squamous epithelium(7) Secretion by exocytosis(8) Movement of mucous across its surface
A. 1, 2, 3, 4, 7 B. 1, 2, 3, 5, 7 C. 2, 3, 4, 7 D. 1, 2, 3, 4, 8 E. 2, 3, 4, 8
The urethra in females is ____ cm long
a. 3.8 b. 20 c. 10 d. 5
The auditory tube
A. amplifies sound waves. B. helps maintain balance. C. carries sound to the eardrum. D. carries sound to the inner ear. E. equalizes air pressure between the middle ear and outside air.