Retrograde signaling occurs when
a. receptors on the presynaptic membrane are activated resulting in a depolarization of the presynaptic dendrites.
b. acetylcholinesterase levels in a synapse are too high .
c. a postsynaptic cell secretes a signaling molecule that influences the sensitivity of the presynaptic terminal.
d. enzymes responsible for the breakdown of the neurotransmitter at a synapse are not produced in sufficient quantity.
e. none of these.
C
You might also like to view...
Which send blood to either esophageal arteries or esophageal branches to supply the esophagus with blood?
A. Thoracic aorta B. Bronchial arteries and left gastric artery C. Thoracic aorta and left gastric artery D. Bronchial arteries E. Left gastric artery
When final velocity is larger than initial velocity, the acceleration is what?
A. zero B. negative C. positive D. average
In both the proximal and distal tubules, the reabsorption of sodium involves the active transport of sodium across the basolateral membrane.
a. true b. false
What is the path of blood from the heart, to the left zygomaticus muscles, and back to the heart?
A. Aorta ? left common carotid artery ? left external carotid artery ? left facial artery ? zygomatic tissues ? left facial vein ? left internal jugular vein ? left subclavian vein ? left brachiocephalic vein ? superior vena cava B. Aorta ? left brachiocephalic artery ? left common carotid artery ? left internal carotid artery ? left occipital artery ? zygomatic tissues ? left maxillary vein ? left internal jugular vein ? left subclavian vein ? left brachiocephalic vein ? superior vena cava C. Aorta ? left brachiocephalic artery ? left common carotid artery ? left external carotid artery ? left facial artery ? zygomatic tissues ? left facial vein ? left internal jugular vein ? left subclavian vein ? superior vena cava D. Aorta ? left common carotid artery ? left internal carotid artery ? left maxillary artery ? zygomatic tissues ? left facial vein ? left external jugular vein ? left subclavian vein ? left brachiocephalic vein ? superior vena cava