ANS Flashcards Preview

Physiology > ANS > Flashcards

Flashcards in ANS Deck (40)
Loading flashcards...
1
Q

Autonomic System overview

A

Motor and sensory pathways regulating body’s internal environment through involuntary control

* Sympathetic

*Parasympathetic

2
Q

Preganglionic neurons

A

Cell body in the CNS

(myelinated B fibers)

3
Q

Postgangliotic neuron

A

Cell body in autonomic ganglia (outside CNS)

(unmyelinated C fibers

4
Q

Activation of ANS

A
  1. Visceral information comes in from body to brain
  2. autonomic centers receive information and initiate response
  3. Hypothalamus
    1. “homeostasis”
  4. Pons
    1. Respirations
  5. medulla
    1. vasomotor tone
    2. respirations
5
Q

ANS has partial control of 4 things

A
  • systemic blood pressure
  • GI motility and secretion
  • urinary bladder emptying
  • sweating and body temperature
6
Q

Structure of sympathetic nervous system

A
  • “Thoracolumbar”
    • pregangliotic neurons cell bodies located in T1-L2/3 of spinal cord- in the intermediolateral horn of gray matter.
      • short
    • post-ganglionic neuron cell bodies are located in the ganglia on either side of the spinal cord.
      • long
7
Q

SNS paravertebral ganglion T1 affects ______

A

head

8
Q

SNS paravertebral ganglion T2 affects _____

A

neck

9
Q

SNS paravertebral ganglion T3-6 affects _____

A

chest

affects phrenic nerve and cardiac accelerant compensation

10
Q

SNS paravertebral ganglion T7-T11 affects

A

abdomen

11
Q

SNS paravertebral ganglion T12-L2 affects ______

A

legs

12
Q

parasympathetic preganglionic neurins arise from:

A
  • Cranial
    • medullary CN 3, 7, 9, 10
  • Sacral
    • spinal cord S2-S4 regions

Long preganglionic neurons, short post

13
Q

Post ganglionic neurons cell bodies of the parasympathetic system are located in:

A
  • target organs
  • discrete ganglia in the head and neck

***Long preganglionic neurons, short post

14
Q

Vagus Nerve (CN X) affects what organs in the parasympathetic nervous system?

A
  1. heart
  2. lungs
  3. esophagus
  4. stomach
  5. small intesting
  6. liver
  7. gallbladder
  8. pancreas
  9. upper uterus
15
Q

Occulomotor Nerve (CN III) affects what organs in the parasympatheic nervous system

A
  1. eye (the pre-ganglionic nucleus is called the Edinger-Westphal nucleus
16
Q

Trigeminal (CNV) affects what in the parasympathetic nervous system?

A
  1. Submandibular gland (secretions)
17
Q

Facial nerve (CNVII) affects what in the parasympathetic nervous system?

A
  1. lacrimal
  2. nasal
  3. submaxillary glands

***pre ganglionic nucleus is calls Superior salivatory nucleus

18
Q

Glossopharyngeal nerve (CNIX) affects what in the parasympathetic nervous system?

A
  1. Parotid gland

***preganglionic nucleus is called the Inferior salivatory nucleus

19
Q

S2-S3 nerves affect what in the parasympathetic nervous system?

A
  1. distal colon
  2. rectum
  3. bladder
  4. lower uterus
  5. external genitalia
20
Q

Edinger-Westphal nucleus is preganglionic input for what postganglionic neuron?

A

Ciliary ganglion

21
Q

Superior Salivatory nucleus is preganglionic nucleus for what postganglionic neuron?

A

Pterygopalatine and submandibular ganglia

22
Q

Inferior salivatory nucleus is preganglionic neuron for what postganglionic neuron?

A

Otic ganglion

23
Q

sympathetic preganglionic fibers

neurotransmitter and receptor

A

Secrete Acetylcholine

Cholinergic (nicotinic)

24
Q

sympathetic postganglionic fibers

neurotransmitter and receptor

A

Secrete Norepinephrine

Receptor type: Adrenergic

or

Secrete ACh to muscarinic receptor or adrenal medulla

25
Q

parasympathetic preganlionic

neurotransmitter and receptor type

A

secretes Acetylcholine

Receptor: Cholinergic (nicotinic)

26
Q

parasympathetic postganlionic fibers

neurotransmitter and receptor

A

secretes Acetylcholine

Receptor type: muscarinic

27
Q

Adrenal Medulla

A

acts like a ganglia but releases NE and Epi as hormones

20% NE

80% Epi

28
Q

sweat glands

A
  • innervated by SNS
  • Postganglionic nerve releases ACh into a muscarinic receptor
  • thus it is a sympathetic cholinergic fiber ???
29
Q

Adenylate cyclase activates cAMP causing _____

A

smooth muscle dilation

30
Q

Acetylcholine

Synthesis and storage

A
  • Synthesis- Choline and acetyl CoA form acetylcholine with help of choline acetyltransferase
  • Storage- stored in synaptic vesicles and released in response to an action potential
31
Q

metabolism of acetylcholine

A
  • <1 msec rapid hydrolysis by acetylcholinesterase to choline and acetate
  • Choline is transported back into nerve endings used for synthesis of new acetylcholine
32
Q

Creation of Epinephrine

A
  1. Tyrosine converted into DOPA by Tyrosine hydroxylase (rate limiting step)
  2. DOPA converted into Dopamine by DOPA decarboxylase
  3. Dopamine converted into Norepinephrine by Dopamine Beta-hydroxylase
  4. Norepi converted into Epinephrine by Phenylethanolamine N-methyltransferase
33
Q

Norepinephrine

formation and storage

A
  • Formation
    • dopamine formed in cytoplasm
    • dopamine enters synaptic vesicle
    • in vesicle it is converted to Norepi
  • storage and release
    • Norepi stored in vesicle until AP
    • with AP the norepi is released from postganglionic SNS nerve endings into ECF via exocytosis
34
Q

Norepinephrine

termination of action

A
  • Reuptake- back into postganglionic sympathetic nerve endings
    • most common
    • 80% of released norepi can be reused
  • Dilution- by diffusion from receptors
  • metabolism- by the enzymes
    • monoamine oxidase (MAO-cytoplasm)
    • catechol-o-methyltransferase (COMT-liver)
35
Q

Epinephrine

formation and storage

A
  • Formation- synthesized in the medulla of the adrenal gland (chromaffin cells)
  • Storage and release- released after stimulation of the adrenal medulla by pre-ganglionic sympathetic neurons by ACh
36
Q

Epinephrine

termination of action

A
  • COMT- liver
  • MAO- cytoplasm
37
Q

what does cAMP do?

A

relaxes muscles

38
Q

Gaq

A
  • increases IP3, DAG and Ca++
  • Vasoconstriction,
  • increased heart contractility
  • increased CNS activity
39
Q

Gai

A
  • decreases cAMP
  • smooth muscle contraction
  • decreased HR
  • decreased contractility
  • decreased CNS activity (post synaptically A2)
40
Q

Gas

A
  • Increased cAMP
  • smooth muscle relaxation/vasodilation
  • Increased HR
  • Increased contractility