ANS Physiology (complete) Flashcards Preview

CV Unit I > ANS Physiology (complete) > Flashcards

Flashcards in ANS Physiology (complete) Deck (13):
1

What are the general characteristics of the ANS?

- Involuntary
- Diffuse projections (not specific)
- Slow action
- Innervates SM, cardiac muscle, and gland cells
- Disynaptic (always 2 synapses)

2

What are the 3 subdivisions of the ANS?

1) Sympathetic (fight/flight)
2) Parasympathetic (rest/digest)
3) Enteric -- semi-autonomous control of digestion

3

Describe the general anatomy of the sympathetic ANS

- Preganglionic neurons originate in thoracic and lumbar spinal cord
- Ganglia located near spinal cord
- 1:10 ratio of pre- to post-ganglionic neurons

4

Describe the general anatomy of the parasympathetic ANS

- Preganglionic neurons originate in brainstem and sacral spinal cord
- Ganglia located near target organs
- 1:3 ratio of pre- to post-ganglionic neurons

5

What is the neurotransmitter used in preganglionic neurons in the ANS?

Acetylcholine (ACh)

6

What are the neurotransmitters used in post-ganglionic neurons of the sympathetic ANS?

- Norepinephrine (NE)
- Epinephrine

7

What is the neurotransmitter used in post-ganglionic neurons of the parasympathetic ANS?

ACh

8

What are the receptors of ACh?

- Nicotinic (depolarizes cell, symp)

OR

- Muscarinic (relaxes cell, parasymp)

9

What are the receptors of NE?

- Alpha-adrenergic
- Beta-adrenergic

10

Describe the adrenal medulla as a sympathetic ganglion

- innervated by pregang symp neurons
- releases NE and epinephrine to bloodstream => sympathomimetic effects

11

Describe the ways ANS regulates HR and force of contraction

Sympathetic stimulation:
- ^ NE => ^ BP
- ^ HR and contractile force
- Vasoconstriction

Parasymp stimulation:
- ^ ACh => Decreased BP
- Decreased HR and contractile force

12

Describe how the baroreceptor reflex affects ANS output

- Low BP => ^ in sympathetic output
- High BP => ^ in parasympathetic output

13

Describe the humoral response to low BP that's controlled by the hypothalamus

- Can stimulate release of hormones that affect BP
- Vasopression (ADH) is a good example
- Low BP detected by subfornical organ => release of vasopression
- Causes vasocontriction => acts on kidneys to ^ H2O retention