Chapter 15: Autonomic Nervous System Flashcards
acetylcholine (ACh)
neurotransmitter that binds at a motor end-plate to trigger depolarization
adrenal medulla
interior portion of the adrenal (or suprarenal) gland that releases epinephrine and norepinephrine into the bloodstream as hormones
adrenergic
synapse where norepinephrine is released, which binds to α- or β-adrenergic receptors
afferent branch
component of a reflex arc that represents the input from a sensory neuron, for either a special or general sense
agonist
any exogenous substance that binds to a receptor and produces a similar effect to the endogenous ligand
alpha-adrenergic receptor
one of the receptors to which epinephrine and norepinephrine bind, which comes in two subtypes: α1 and α2
antagonist
any exogenous substance that binds to a receptor and produces an opposing effect to the endogenous ligand
anticholinergic drugs
drugs that interrupt or reduce the function of the parasympathetic system
autonomic tone
tendency of an organ system to be governed by one division of the autonomic nervous system over the other, such as heart rate being lowered by parasympathetic input at rest
baroreceptor
mechanoreceptor that senses the stretch of blood vessels to indicate changes in blood pressure
beta-adrenergic receptor
one of the receptors to which epinephrine and norepinephrine bind, which comes in three subtypes: β1, β2, and β3
cardiac accelerator nerves
preganglionic sympathetic fibers that cause the heart rate to increase when the cardiovascular center in the medulla initiates a signal
cardiovascular center
region in the medulla that controls the cardiovascular system through cardiac accelerator nerves and vasomotor nerves, which are components of the sympathetic division of the autonomic nervous system
celiac ganglion
one of the collateral ganglia of the sympathetic system that projects to the digestive system
central neuron
specifically referring to the cell body of a neuron in the autonomic system that is located in the central nervous system, specifically the lateral horn of the spinal cord or a brain stem nucleus
cholinergic
synapse at which acetylcholine is released and binds to the nicotinic or muscarinic receptor
chromaffin cells
neuroendocrine cells of the adrenal medulla that release epinephrine and norepinephrine into the bloodstream as part of sympathetic system activity
ciliary ganglion
one of the terminal ganglia of the parasympathetic system, located in the posterior orbit, axons from which project to the iris
collateral ganglia
ganglia outside of the sympathetic chain that are targets of sympathetic preganglionic fibers, which are the celiac, inferior mesenteric, and superior mesenteric ganglia
craniosacral system
alternate name for the parasympathetic division of the autonomic nervous system that is based on the anatomical location of central neurons in brain-stem nuclei and the lateral horn of the sacral spinal cord; also referred to as craniosacral outflow
dorsal longitudinal fasciculus
major output pathway of the hypothalamus that descends through the gray matter of the brain stem and into the spinal cord
dorsal nucleus of the vagus nerve
location of parasympathetic neurons that project through the vagus nerve to terminal ganglia in the thoracic and abdominal cavities
edinger-westphal nucleus
location of parasympathetic neurons that project to the ciliary ganglion
efferent branch
component of a reflex arc that represents the output, with the target being an effector, such as muscle or glandular tissue
endogenous
describes substance made in the human body
endogenous chemical
substance produced and released within the body to interact with a receptor protein
epinephrine
signaling molecule released from the adrenal medulla into the bloodstream as part of the sympathetic response
exogenous
describes substance made outside of the human body