Which of the following statements regarding neurotransmitters is TRUE?
A. Acetylcholine is broken down by enzymes present on postsynaptic cell membranes.
B. Acetylcholine that is released at synapses binds to adrenergic receptors in the postsynaptic cell membrane.
C. Catecholamines are the most abundant neurotransmitters in the central nervous system.
D. Opiate drugs, such as morphine, are antagonists of a class of neurotransmitters called endorphins.
E. Gamma-aminobutyric acid (GABA) is a major excitatory transmitter in the central nervous system.
A
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These events occur during the development of the nervous system: a: Neural groove formsb: Neural folds approach one anotherc: Neural crest cells pinch off from the neural foldsd: Neural folds fuse to form neural tubeWhich is the correct chronological order for the events?
A. b a, d, c B. c a, b, d C. c, b, d, a D. a, c, b, d E. a, b, c, d
Atrial natriuretic peptide causes __________ of afferent arterioles and _________ of mesangial cells
A. constriction; contraction B. constriction; relaxation C. dilation; contraction D. dilation; relaxation
Answer the following statements true (T) or false (F)
1. At the site of an injury, platelets become sticky and form a platelet plug. 2. Vitamin K stimulates the liver to produce more fibrinogen, which helps the blood clot more efficiently. 3. A thrombus is a clot that stays in the place where it was formed. 4. An embolus is part of a clot that has become dislodged and circulates through the bloodstream. 5. If a patient were having a heart attack caused by a blood clot, heparin would be an effective treatment in dissolving the clot.
Sensory receptors are specialized cells or multicellular structures that collect information from the environment and stimulate neurons to send impulses along sensory fibers to the brain.
Answer the following statement true (T) or false (F)