Flashcards in Week 8 - Chapter 13 (Peripheral Nervous System Physiology) Deck (29):
the transmitter released by
(1) all preganglionic neurons of the parasympathetic nervous system & sympathetic nervous system,
(3) all postganglionic neurons of the parasympathetic nervous system,
(4) all motor neurons to skeletal muscles, and
(5) most postganglionic neurons of the sympathetic nervous system that go to sweat glands.
an enzyme present in abundance on the surface of the postjunctional cell. AChE degrades ACh into two inactive products: acetate and choline.
Adrenergic Receptor (and subtypes)
receptors that mediate responses to epinephrine (adrenaline) and norepinephrine. These receptors mediate responses at all junctions where norepinephrine or epinephrine is the transmitter.
-Alpha 1 & Alpha 2
-Beta 1 & Beta 2
Alpha1 Receptor (locations and function)
-male sex organs,
-prostatic capsule, and
-bladder (trigone and sphincter).
Causes pupil dilation, vasoconstriction, ejaculation, and bladder contraction and prostatic contraction.
Alpha2 Receptors (locations and function)
Located on nerve terminals, not organs innervated by the ANS.
Referred to as presynaptic. The function of these receptors is to regulate transmitter release..
Autonomic Nervous System and what does it regulate
One of the subdivision of the Peripheral Nervous System. three principal functions:
(1) regulation of the heart;
(2) regulation of secretory glands (salivary, gastric, sweat, and bronchial glands); and
(3) regulation of smooth muscles (muscles of the bronchi, blood vessels, urogenital system, and GI tract).
Autonomic Tone is the...
steady, day-to-day influence exerted by the autonomic nervous system on a particular organ or organ system. Autonomic tone provides a basal level of control over which reflex regulation is superimposed.
Baroreceptor Reflex (locations, function, response)
1) Baroreceptors located in the carotid sinus and aortic arch monitor changes in blood pressure and send this information to the brain.
(2) In response, the brain sends impulses along nerves of the autonomic nervous system, instructing the heart and blood vessels to behave in a way that restores blood pressure to normal.
Beta1 Receptors (locations and function)
-increases heart rate, force of contraction, and velocity of impulse conduction through the atrioventricular node.
-release of renin--> angiotensin synthesis--> vasoconstriction--> increased blood pressure
Beta2 Receptors (location and function)
Arterioles of the:
Activation only by Epinephrin and leads to:
-relaxation uterine smooth muscle.
-vasodilation of arterioles of the heart, lungs, and skeletal muscle
-in the liver activation promotes glycogenolysis (breakdown of glycogen into glucose), thereby increasing blood levels of glucose.
-skeletal muscle enhances contraction.
Central Nervouse System
the complex of nerve tissues that controls the activities of the body. In vertebrates it comprises the brain and spinal cord.
Cholinergic Receptors (and subtypes)
-receptors that mediate responses to acetylcholine.
-These receptors mediate responses at all junctions where acetylcholine is the transmitter.
-Muscarinic (target organs)
Dopamine Receptor (location and function)
-only clinical significance is that its located in the vasculature of the kidney.
-Activation dilates renal blood vessels, enhancing renal perfusion.
Information picked up by the sensor is sent to the CNS (spinal cord and brain), where it is integrated with other relevant information. Signals (instructions for change) are then sent from the CNS along nerves of the autonomic system to the effector. In response to these instructions, the effector makes appropriate adjustments in the process. The entire procedure is called a reflex.
the major transmitter released by the adrenal medulla. (The adrenal medulla also releases some norepinephrine.)
-located on target organs of the parasympathetic nervous system
(1) increased glandular secretions (from pulmonary, gastric, intestinal, and sweat glands);
(2) contraction of smooth muscle in the bronchi and GI tract;
(3) slowing of heart rate;
(4) contraction of the sphincter muscle of the iris, resulting in miosis (reduction in pupillary diameter);
(5) contraction of the ciliary muscle of the eye, causing the lens to focus for near vision;
(6) dilation of blood vessels; and
(7) voiding of the urinary bladder (by causing contraction of the detrusor muscle [which forms the bladder wall] and relaxation of the trigone and sphincter muscles [which block the bladder neck when contracted]).
causes contraction of skeletal muscle
NicotinicN Receptor activation
-promotes ganglionic transmission at all ganglia of the sympathetic and parasympathetic nervous systems.
-release of epinephrine from the adrenal medulla.
Norepinepherine is the transmitter released by
-all postganglionic neurons of the sympathetic nervous system.
-The only exceptions are the postganglionic sympathetic neurons that go to sweat glands, which employ acetylcholine as their transmitter.
Parasympathetic Nervous System
Subdivision of the Autonomic Nervous System.
• Slowing of heart rate
• Increased gastric secretion
• Emptying of the bladder
• Emptying of the bowel
• Focusing the eye for near vision
• Constricting the pupil
• Contracting bronchial smooth muscle
Peripheral Nervous System
The peripheral nervous system has two major subdivisions: (1) the somatic motor system and (2) the autonomic nervous system.
the neurons that go from the ganglia to effector organs
the neurons that go from the junction to effector organs
The neurons that go from the spinal cord to the parasympathetic ganglia
The neurons that go from the spinal cord to the junction
Transmission is terminated by reuptake of norepinephrine back into the nerve terminal. (Note that the termination process for norepinephrine differs from that for ACh, whose effects are terminated by enzymatic degradation rather than reuptake.) Following reuptake, norepinephrine can undergo one of two fates: (1) uptake into vesicles for reuse or (2) inactivation by monoamine oxidase (MAO), an enzyme found in the nerve terminal.
The purpose of the sensor is to monitor the status of a physiologic process
Somatic Motor System controls..
The somatic motor system controls voluntary movement of muscles. The two subdivisions of the autonomic nervous system regulate many involuntary processes.