2.3 Autonomic Nervous System Flashcards Preview

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Flashcards in 2.3 Autonomic Nervous System Deck (59):
1

Somatic nervous system

Perceptible and voluntary

2

Autonomic nervous system

Imperceptible and involuntary

3

Another term for parasympathetic division

Craniosacral division

4

Where are the preganglionic neurons located in the parasympathetic division?

Cranial nuclei and sacral region of spinal cord

5

Function of Parasympathetic nervous system

Digestion and energy storage... rest & digest

6

Another term for sympathetic division

Thoracocolumbar division

7

Function of sympathetic division of autonomic nervous system

Energy mobilization and distribution... Fight or flight

8

Where are the cell bodies of preganglionic neurons located in the sympathetic division?

Thoracic and lumbar regions of the spinal cord

9

SymNS and ParaNS are...

Mutually inhibitory -Increase in activity in one leads to decrease in activity of the other

10

What actions does the Parasympathetic division do?

-Activates digestive processes -Promotes nutrient storage (liver, muscle) -Slows heart rate and reduces blood pressure

11

What actions does the sympathetic division do?

-Mobilizes nutrients (glucose) into bloodstream -Increases cardiac output----> Increase perfusion of active tissue -Dilates bronchiole tubes--> Increased ventilation -Slows digestion and other non-essential organ systems

12

The parasympathetic neuron has a ________ preganglionic neuron, and synapses near_______

Long Target organ

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The sympathetic neuron has a ________ preganglionic neuron and synapses near_______

Short Spinal column (long postganglionic neuron)

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All preganglionic neurons are...

Cholinergic, they release acetylcholine at the synapse

15

When ACh is released from the preganglionic neuron, it binds....

Post synaptic nicotinic ACh receptors -->Na+ ion channels (fast) --> Always EPSPs

16

Where does the nicotinic name of the receptor come from?

Their ability to be activated by nicotine

17

What does the postganglionic fiber in the parasympathetic division release?

Acetylcholine

18

What does the acetylcholine released from the postganglionic fibers bind to on effector target tissues?

Muscarinic receptors (sustained / slower acting GPCRs)

19

What does the binding of acetylcholine to muscarinic receptors in the parasympathetic division cause?

EPSPs or IPSPs depending on the tissue

20

Where do muscarinic receptors get their name?

They bind muscarine compound from poisonous mushrooms

21

Parasympathetic pathway (entire thing)

1. Preganglionic fibers release acetylcholine 2. Acetylcholine binds postsynaptic nicotinic receptors 3. Binding causes influx of Na+ into postganglionic neuron 4. Postganglionic fibers release acetylcholine 5. Acetylcholine binds muscarinic receptors on effector target tissues 6. Causes EPSPs or IPSPs

22

The majority of post-ganglionic fibers in the sympathetic division release what?

Norepinephrine!

23

Two pathways for sympathetic division

Acetylcholine-->Acetylcholine Acetylcholine--> Norepinephrine

24

Sympathetic pathway (most common one)

1. Preganglionic fibers release acetylcholine 2. Acetylcholine binds postsynaptic nicotinic receptors 3. Binding causes influx of Na+ and leads to EPSP on postganglionic neuron 4. Adrenergic neurons release norepinephrine 5. Norepinephrine binds adrenergic receptors on target cell (also GCPRs) 6. Cause EPSPs or IPSPs on target tissues (often muscles or glands)

25

What are target cells of the ACh pathway in the sympathetic nervous system?

Sweat glands, and blood vessels in muscle tissue

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What are the target tissues of the norepinephrine pathway in the sympathetic division?

Most other tissues

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Varicosites

At axon terminus of postganglionic adrenergic neurons

Enables widepread secretion of NE at synapses throughout the effector organs---> Activates adrenergic receptors that stimulate (inhibit) target tissues 

"Showers" cells in norepinephrine

 

28

Where / what does preganglionic ACh activate in the sympathetic division?

Adrenal medulla (inner)

Specifically chromaffin cells

NO postganglionic neuron!!

29

What do chromaffin cells release?

Epinephrine (adrenaline) and norepinephrine as HORMONES which bind adrenergic receptors on tarhet tissues via the bloodstream 

Global, body-wide effect that lasts longer than neurotransmitters

30

What do both epinephrine and norepinephrine both bind?

Alpha and beta adrenergic receptors

31

What are aplha and beta adrenergic receptors?

G-protein coupled receptors, not ion channels 

Can be stimulatory (alpha and beta) or inhibitory (mostly beta)

32

Effects of both epinephrine and norepinephrine on brain 

Alertness

33

Effects of both epinephrine and norepinephrine on liver

Glucose release

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Effects of both epinephrine and norepinephrine on heart

Increased rate / strength of contraction

35

Other effects of norepinephrine and epinephrine

Bronchiolar dilation, increased diaphragm contraction, reduced digestion, inhibits pain perception

36

Difference between epinephrine and norepinephrine

Norepinephrine works better as a neurotransmitter and epinephrine is more of a hormone

37

What are beta blockers?

Bring down blood pressure, a lot of men take them, block beta adrenergic binding site to reduce effects of epinephrine and norepinephrine

38

Somatic nervous system (system)

1 neuron

39

Autonomic nervous system (system)

Neurotransmitters, hormones and effectors

40

Review slide 15!!!!

41

ANS functions: 3 body scenarios 

  • Relaxation / sleep
  • Vidorous exercise
  • Stress response

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Relaxation / sleep

-Energy storage and tissue repair

-Parasympathetic division predominates

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Vigorous Exercise

-Mobilization and distribution of energy resources

-Sympathetic division predominates

44

Stress response

-Anticipation of the "fight"

-Sympathetic division and CRH / ACTH / cortisol release

45

Digestive tract during relaxation / sleep

Increased secretion from salivary glands, gastric glands, exocrine pancreas

Increased motility of GI smooth muscle

Contraction of gall bladder smooth muscle 

Increased insulin secretion pancreatic beta cells

46

Respiratory system during relaxation / sleep

Contraction of bronchial smooth muscle (constricts bronchi)

47

Cardiovascular system during relaxation / sleep

Decreased MAP (mean arterial pressure)

Decreased cardiac output

Decreased sympathetic outflow --> Relaxation of vascular smooth muscle --> Dilation of blood vessels --> Decreased resistance

-->Decreased MAP

48

Digestive tract during exercise

Decreased activity

49

Respiratory system during exercise

Increased ventilation

- Relaxation of bronchial smooth muscle (dilates bronchi)

50

Cardiovascular system during exercise

Increased MAP and perfusion

-Increased dilation of vascular smooth muscle in active skeletal muscles--> increased local blood flow to active muscles

51

Adrenal medulla during exercise

Mobilization of energy

-Release of epinephrine

-Glycogen breakdown by muscle and liver

-Fat breakdown in fat cells

52

Skin during exercise

Heat dissipation during vigorous and prolonged exercise

-Increased core temperature because of increased metabolic activity

-Increased activation of sweat glands (via acetylcholine at muscarinic receptors)

-Increased blood flow to skin (increased core temperature overrides constriction of vascular smooth muscle)

53

Stress perception in the short term elicited in the 

 

Amygdala--> hypothalamus-->ANS increased sympathetic outflow.. medullary epinephrine and norepinephrine release

54

Effects of short term stress response

Increased MAP

Decreased GI motility

Increase in sweat secretion

55

Chronic, long term stress activates...

Adrenocorticotropic axis for more sustained, prolonged response

56

Hypothalamic control of the chronic stress response

CRH-->ACTH-->Cortisol (released from adrenal CORTEX)

57

Cortisol

Effects similar to epinephrine, but  much more long term

58

Acute effects of cortisol (the stress hormone)

Good, help performance

-Increased breakdown of fat and protein

-Increased gluconeogenesis in liver

-Increased blood glucose levels --> Feul for performance

 

59

Chronic effects of cortisol

Bad, make you sick

Decreased immune functions (immune supression), decreased resistance to disease

Tissue "wasting" due to protein loss

May lead to depression