Autonomic Nervous System- Sns

Front 1

What is the primary function of the ANS?

Back 1

is to maintain constancy of the internal environment, ie, homeostasis

Front 2

ANS regulates?

Back 2

visceral fxns necessary for homeostasis, eg, BP, body temp, plasma osmolality and glucose conc.

Front 3

What are the two major divisions of the ANS?

Back 3

1. SNS
2. PNS

Front 4

Components of the ANS include?

Back 4

1. Autonomic sensory nerves
2. Autonomic motor (effector) nerves

Front 5

Autonomic sensory nerves do what?

Back 5

monitor internal variables, such as BP, blood chemistry, body temp, etc.

Front 6

Autonomic motor (effector) nerves

Back 6

nerves that innervate targets (cells, organs, glands) and cause necessary adjustments in target activity to maintain homeostasis

Front 7

Effector nerves arise?

Back 7

outside of the central nervous system in autonomic ganglia

Front 8

Sympathetic nerve tracts descend from>?

Back 8

the hypothalamus and brainstem autonomic nuclei and synapse with preganglionic nerve cell bodies located in lateral horns of the spinal cord (T1-L2)

Front 9

Sympathetic preganglionic nerve axons exit the spinal cord via? type of output?

Back 9

the ventral (anterior) roots; thus, sympathetic outflow from the CNS is a thoracolumbar output

Front 10

What do sympathetic preganglionic nerve axons travel in?

Back 10

white (myelinated) rami

Front 11

Sympathetic preganglionic nerve axons travel in white rami to?

Back 11

22 pairs of paravertebral ganglia (the sympathetic chains) located on either side of the vertebral column

Front 12

#1. Some sympathetic preganglionic nerve axons synapse with?

Back 12

sympathetic postganglionic nerves in the paravertebral ganglia

Front 13

#2. Some preganglionic nerve axons from upper thoracic segements travel up to the?

Back 13

3 cervical ganglia and synapse with postganglionic nerves there=sympathetic innervation of the head and neck

Front 14

#3. Some preganglionic nerve axons from?

Back 14

T5 to T11 exit the sympathetic chains leave as the splanchnic nerves and synapse with postganglionic nerves in the celiac ganglion in the abdomen

Front 15

#1. Some postganglionic nerve axons in the sympathetic chains travel back to?

Back 15

the spinal nerves via gray (unmyelinated) rami; these nerve axons travel in peripheral nerves to innervate vascular smooth muscle of arterioles, veins and sweat glands

Front 16

#2. Some postganglionic nerve axons exit?

Back 16

sympathetic ganglia and travel to specific target organs -- eye, heart, lungs, liver, GI tract, kidney

Front 17

What is the exception to the general arrangement?

Back 17

some sympathetic preganglionic nerve axons in the splanchnic nerves innervate chromaffin cells of the adrenal medulla (don't synapse with post-synaptic nerves)

Front 18

What do the chromaffin cells and adrenal medulla release?

Back 18

NE and epinephrine into the blood, these hormones can then circulate to various tissues and act on specific receptors

Front 19

What is the neurotransmitter released from sympathetic preganglionic nerve endings?

Back 19

ACh-therefore they are cholinergic nerves, ACh receptors on the sympathetic postganglionic nerves are nicotinic receptors

Front 20

What is the neurotransmitter released from nearly all sympathetic postganglionic nerve endings?

Back 20

NE, adrenergic nerves, adrenergic receptors (there are some sympathetic cholinergic postganglionic nerves)

Front 21

Receptors that bind NE and epi are?

Back 21

adrenergic receptors

Front 22

NE is stored in?

Back 22

synaptic vesicles in postganglionic nerve endings until release is stimulated by a nerve impulse

Front 23

What are the events involved with neurotransmission at the sympathetic postganglionic nerve terminal

Back 23

1. AP arrives at nerve terminal--depolarization of terminal
2. Voltage-gated ion channels open, Ca diffuses into the nerve terminal, stimulating exocytosis of NE into the synaptic cleft
3. NE diffuses across the cleft and binds to adrenergic receptors on the postsynaptic membrane, ie, the target cell membrane

Front 24

NE also binds to ?

Back 24

autoreceptors on the presynaptic nerve membrane--negative feedback control of NE release

Front 25

After NE acts on adrenergic receptors...?

Back 25

NE is taken back up by the presynaptic nerve terminal and most (80%) is restored in vesicles--this process is referred to as reuptake and terminates the action of NE on the target cells

Front 26

What is the remainder of NE taken up by?

Back 26

the nerve terminal is metabolized by MAO in the nerve terminal, and must be replaced by newly synthesized NE

Front 27

Circulating NE and epi are metabolized by the enzyme?

Back 27

catechol-O-methyl transferase (COMT) in the blood and liver

Front 28

Name two catecholamines?

Back 28

NE and Epi

Front 29

Name adrenergic receptors

Back 29

alpha-1, alpha-2, beta-1, beta-2

Front 30

Which adrenergic receptors are postsynaptic?

Back 30

alpha-1, alpha-2, beta-1, beta-2

Front 31

Which adrenergic receptors are presynaptic?

Back 31

alpha-2

Front 32

beta-1 in SA node?

Back 32

increases heart rate

Front 33

beta-1 in AV node?

Back 33

increased conduction velocity

Front 34

beta-1 in ventricular myocardium?

Back 34

increased contractility

Front 35

alpha-1 in cutaneous?

Back 35

vasoconstriction

Front 36

alpha-1 in visceral?

Back 36

vasoconstriction

Front 37

alpha-1 in skeletal muscle?

Back 37

vasocontriction

Front 38

beta-2 in skeletal muscle?

Back 38

vasodilation (epinephrine)

Front 39

alpha-1 in blood vessels?

Back 39

venoconstriction

Front 40

beta-1 in juxtaglomerular cells

Back 40

increased renin release

Front 41

beta-2 in bronchiolar smooth muscle

Back 41

bronchodilation (epinephrine)

Front 42

alpha-1 in pupil?

Back 42

dilation (mydriasis)

Front 43

Alpha-1 adrenergic stimulation

Back 43

1. arteriolar vasoconstriction
2. venous constriction and increased return to the heart

Front 44

Alpha-1 adrenergic stimulation

Back 44

#1. arteriolar vasconstriction; increased peripheral vascular resistance can cause an increase in BP
#2. venous constriction and increased venous return to heart; increase in SV and CO can elevate BP

Front 45

venous constriction and increased venous return to the heart

Back 45

increase in stroke volume and cardiac output can elevate BP

Front 46

Beta-1 adrenergic stimulation

Back 46

1. HR increases- contributes to increase in cardiac output and BP
2. myocardial contractility increases- increase in stroke volume and CO and contribute to increase in BP

Front 47

Beta-2 adrenergic stimulation aka?

Back 47

Epinephrine effect

Front 48

beta-2 adrenergic stimulation of skeletal muscle..

Back 48

dilation of skeletal muscle blood vessels and increased skeletal muscle blood flow

Front 49

What are some metabolic effects of SNS activation?

Back 49

1. Glycogenolysis in the liver
2. Lipolysis in adipose tissue
3. Insulin secretion from the pancreas (beta cells)

Front 50

Glycogenolysis in the liver is mediated via?

Back 50

beta-2 adrenergic receptors- epinephrine effect

Front 51

Glycogenolysis in the liver causes?

Back 51

release of glucose to the blood-- ensures sufficient energy supply for the CNS

Front 52

Lipolysis in adipose tissue mediated via?

Back 52

beta-2 adrenergic receptors- epinephrine effect

Front 53

Lipolysis in adipose tissue causes?

Back 53

release of fatty acids for use primarily by muscle

Front 54

Insulin secreted from the pancreas is inhibited by?

Back 54

activation of alpha-1 receptors

Front 55

Summary of epinephrine effects mediated via beta-2 receptors

Back 55

1. Vasodilation of skeletal muscle arterioles
2. Glycogenolysis
3. Lipolysis
4. Bronchodilation