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Flashcards in Autonomic Nervous System Deck (23):
1

Autonomic Nervous System Overview

- visceral motor division of PNS

innervates:

  • smooth muscle
  • cardiac muscle
  • glands

regulates

  • heart rate
  • blood pressure
  • digestion
  • urination

2

Autonomic Motor Systems

- a chain of two motor neurons: postganglionic and preganglionic

- connected by autonomic ganglion

- differs from somatic motor system having only 1 neuron

3

Autonomic vs. Somatic Motor Systems

Autonomic: involuntary control of glands, cardiac and smooth muscle via two nerve fibers from CNS using acetylcholine or norepinephrine for excitatory or inhibitory effect

Somatic: voluntary control of skeletal muscle via one nerve fiber from the CNS using acetylcholine only for excitatory effect

4

Divisions of Autonomic Nervous System

Sympathetic - "fight or flight"

Parasympathetic - "rest and digest"

- innervate mostly same structures but cause oppostie effects

5

Sympathetic Nervous System

- "fight or flight" response

- activated when extra metabolic effort is necessary

Effects:

  • increased heart rate
  • fast, deep breathing
  • dilated pupils
  • increased skeletal muscle blood supply
  • digestion inhibited

- thoracolumbar origin (T1-L2)

6

Parasympathetic Nervous System

- "rest and digest"

- relaxes the body and controls routine maintenance functions

- concerned with conserving energy

- craniosacral origin

7

Location of Autonomic Ganglia

sympathetic - close to CNS

parasympathetic - close to or within effector organ

8

Length of Preganglionic Autonomic Nerve Fibers

Sympathetic - short

Parasympathetic - long

 

9

Length of Postganglionic Autonomic Nerve FIbers

sympathetic - long

parasympathetic - short

10

Origins of Autonomic Nerves

Sympathetic - thoracolumbar ( T1-L2)

Parasympathetic - craniosacral

11

Branching of Autonomic Nerve Axons

Sympathetic - highly branched to influence many organs

Parasympathetic - few branches for localized effect

12

Neurotransmitter used by ALL preganglionic autonomic axons.

Acetylcholine

(both para- and sympathetic)

13

Neurotransmitter in most postganglionic sympathetic nerve fibers

Norepinephrine

- known as adrenergic synapses

14

Neurotransmitter in all postganglionic parasympathetic nerve fibers

Acetylcholine

- known as Cholinergic synapses

15

location of sympathetic chain ganglia

Paravertebral - on either side of vertebrae

16

name for the columns of ganglia on either side of the spine/spinal cord

Q image thumb

Sympathetic Trunks

- ganglia are fused so fewer ganglia than spinal nerves

- originate from T1 to L2

- 3 cervical, 11 thoracic, 4 lumbar, 4 sacral, 1 coccygeal

17

the ganglia shown here AND the term for their location

Q image thumb

Collateral Ganglia

Prevertebral Location (AKA prevertebtral ganglia)

- lie anterior to the aorta in the abdomen and pelvis

- not paired or segmentally arranged like sympathetic trunks

 

18

two divisions of parasympathetic outflow

Cranial - originates from brain

Sacral - originates from sacral region of spinal cord

19

Cranial Outflow (of parasympathetic NS)

- originates from brain via cranial nerves

Innervates: organs of head, neck, thorax, abdomen

20

Sacral Outflow (of parasympathetic NS)

- originates from sacral spinal cord

innervates: remaining abdominal and pelvic organs

21

Cranial Nerves Containing Preganglionic Parasympathetic Fibers

III Oculomotor

VII Facial

IX Glossopharyngeal

X Vagus

22

Dual Innervation

- innervation of same organ by both para- and sympathetic NSs

Can have two different effects:

Antagonistic Effect: each division innervates different cells to create opposing effects

ex: pupillary dilator muscle (sympathetic) vs. constrictor pupillae (parasympathetic)

Cooperative Effect: both divisions cause same effect

ex: parasympathetic increases salivary serous cell secretion, sympathetic increases salivary mucous secretion

23

Single Innervation

- some effectors receive only sympathetic:

  • adrenal medulla
  • arrector pili
  • sweat glands
  • many blood vessels