Tetanic muscle contractions don't occur in a normal cardiac muscle because
A) cardiac muscle tissue contracts on its own.
B) neural stimulation is lacking.
C) the refractory period lasts until the muscle relaxes.
D) the refractory period ends before the muscle reaches peak tension.
E) potassium channels outnumber sodium channels.
C
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In the diagram, where is the crista galli?
a) C b) A c) B d) E e) G
Which of the following is not characteristic of the cytoskeleton?
a. the cytoskeleton supports the plasma membrane and is responsible for the particular shape, rigidity, and spatial geometry of each different cell type. b. the cytoskeleton probably plays a role in regulating cell growth and division. c. the cytoskeletal elements are all rigid, permanent structures. d. the cytoskeleton is responsible for cell contraction and cell movements. e. the cytoskeleton supports and organizes the ribosomes, mitochondria, and lysosomes.
The anatomical term that means "away from the midline of the body" is ________.
A. proximal B. lateral C. medial D. superficial E. distal
Which of the following would you most likely NOT find in a neuron?
A. mitochondria B. lysosomes C. centrioles D. Golgi apparatus E. Nissl bodies or chromatophilic substance