When light strikes a photoreceptor it
A. deporlarizes and releases more neurotransmitter.
B. depolarizes and releases less neurotransmitter.
C. hyperpolarizes and releases more neurotransmitter.
D. hyperpolarizes and releases less neurotransmitter.
D
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The presence of ____________________ in the stomach is the main stimulus to enhance gastric secretion
Fill in the blank(s) with correct word
Which is not a portion of the urethra?
A. external urethral orifice B. internal urethral sphincter C. prostatic urethra D. membranous urethra E. spongy urethra
When a neuromodulator slows the reuptake of a neurotransmitter or causes expression of an increased number of receptors on postsynaptic neurons, the effect is called
A. presynaptic potentiation. B. recruitment. C. spatial summation. D. facilitation. E. temporal summation.
A sarcomere is the
A. contractile thread that extends the length of the muscle fiber. B. plasma membrane of a muscle fiber. C. protein strand composed of actin or myosin. D. structural and functional unit of the skeletal muscle fiber. E. cytoplasm of a muscle fiber.