Week 8 - Chapter 13 (Peripheral Nervous System Physiology)

Question 1

Acetylcholine

Answer 1

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.

Question 2

Acetylcholinesterase

Answer 2

an enzyme present in abundance on the surface of the postjunctional cell. AChE degrades ACh into two inactive products: acetate and choline.

Question 3

Adrenergic Receptor (and subtypes)

Answer 3

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
• Dopamine

Question 4

Alpha1 Receptor (locations and function)

Answer 4

• eyes,
• blood vessels,
• male sex organs,
• prostatic capsule, and
• bladder (trigone and sphincter).

Causes pupil dilation, vasoconstriction, ejaculation, and bladder contraction and prostatic contraction.

Question 5

Alpha2 Receptors (locations and function)

Answer 5

Located on nerve terminals, not organs innervated by the ANS.
Referred to as presynaptic. The function of these receptors is to regulate transmitter release..

Question 6

Autonomic Nervous System and what does it regulate

Answer 6

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).

Question 7

Autonomic Tone is the…

Answer 7

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.

Question 8

Baroreceptor Reflex (locations, function, response)

Answer 8

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.

Question 9

Beta1 Receptors (locations and function)

Answer 9

• heart
• kidney.

activation:

• increases heart rate, force of contraction, and velocity of impulse conduction through the atrioventricular node.
• release of renin–> angiotensin synthesis–> vasoconstriction–> increased blood pressure

Question 10

Beta2 Receptors (location and function)

Answer 10

Arterioles of the:
-heart,
-lungs
-skeletal muscles
-bronchi
-uterus
-liver
Activation only by Epinephrin and leads to: 
-bronchial dilation,
-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.

Question 11

Central Nervouse System

Answer 11

the complex of nerve tissues that controls the activities of the body. In vertebrates it comprises the brain and spinal cord.

Question 12

Cholinergic Receptors (and subtypes)

Answer 12

• receptors that mediate responses to acetylcholine.
• These receptors mediate responses at all junctions where acetylcholine is the transmitter.
• NicotinicN (neuronal)
• NicotinicM (muscle)
• Muscarinic (target organs)

Question 13

Dopamine Receptor (location and function)

Answer 13

• only clinical significance is that its located in the vasculature of the kidney.
• Activation dilates renal blood vessels, enhancing renal perfusion.

Question 14

Effector

Answer 14

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.

Question 15

Epinepherine

Answer 15

the major transmitter released by the adrenal medulla. (The adrenal medulla also releases some norepinephrine.)

Question 16

Muscarinic Receptor

Answer 16

• located on target organs of the parasympathetic nervous system
• activation causes
  (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]).

Question 17

NicotinicM Receptors

Answer 17

causes contraction of skeletal muscle

Question 18

NicotinicN Receptor activation

Answer 18

• promotes ganglionic transmission at all ganglia of the sympathetic and parasympathetic nervous systems.
• release of epinephrine from the adrenal medulla.

Question 19

Norepinepherine is the transmitter released by

Answer 19

• 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.

Question 20

Parasympathetic Nervous System

Answer 20

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

Question 21

Peripheral Nervous System

Answer 21

The peripheral nervous system has two major subdivisions: (1) the somatic motor system and (2) the autonomic nervous system.

Question 22

Postganglionic neurons

Answer 22

the neurons that go from the ganglia to effector organs

Question 23

PostJunctional neurons

Answer 23

the neurons that go from the junction to effector organs

Question 24

Preganglionic neurons

Answer 24

The neurons that go from the spinal cord to the parasympathetic ganglia

Question 25

Prejunctional neurons

Answer 25

The neurons that go from the spinal cord to the junction

Question 26

Reuptake

Answer 26

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.

Question 27

Sensor

Answer 27

The purpose of the sensor is to monitor the status of a physiologic process

Question 28

Somatic Motor System controls..

Answer 28

The somatic motor system controls voluntary movement of muscles. The two subdivisions of the autonomic nervous system regulate many involuntary processes.

Question 29

Sympathetic Nervous System function…

Answer 29

Three main functions:
• Regulating the cardiovascular system
• Regulating body temperature
• Implementing the acute stress response (commonly called a “fight-or-flight” reaction)