Parasympathetic NS Flashcards

1
Q

Parasympathetic NS =

A

REST & DIGEST!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are reflex arcs?

A

Feedb. control mechanisms!

  • unmyelinated AFFERENT SENSORY FIBRES from visceral R’s monitor body status; the info. is integrated in BRAINSTEM & HYPOTHALAMUS
  • Descending info. flow is adjusted to compensate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What signaling does the Parasympathetic NS specialise in?

A

Organised for DISCRETE & LOCALISED SIGNALING

(long pregang. fibre with postgang. fibre located close(r) to target organ)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are some of the Parasymp. NS main goals?

A

Conservation of energy

Maintence of organ funtions at rest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What do cranial nerves innervate?

Where do the originate from?

A
  • Originate in BRAINSTEM!
  • Innervate ganglia in heart, lung, digestive syst organs, eyes, glands
    e. g. VAGUS NERVE

–carries AFFERENT - visceral sensory info.

–carries EFFERENT - parasymp. regulation of heart and other organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What do spinal nerves innervate?

Where do they orginate from?

A
  • Originate from SACRAL REGION!
  • Innervate ganglia is intestine, bladder & reproductive organs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are some unique characteristics of the Parasymp. NS?

A

Parasymp. syst. shows LITTLE DIVERGENCE

PRECISE LOCAL CONTROL of target organs

Each pregang. neuron controls only 1-3 POSTGANG. NEURONS (in contrast to high divergence of symp. syst.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What neurotransmitter is used in the parasymp. NS?

A

Neurotransmitter = ACh

[pre- and postgang. neurons]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the 2 types of ACh receptors involved in the parasymp. NS?

A

Nicotinic

Muscarinic (=GPCR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What type of R is the postgang. neuron R?

A

nACHR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What type of R is the target organ R?

A

mAChR (=GPCR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

mACHR’s are GPCR.

THUS how many subtypes exist? Show whether these sutypes are excitatory or inhibitory. What do these specialisations depend on?

A

5 subtypes!

M1 –> M5

[M1 & M3 = EXCITATORY]

[M2 = INHIBITORY]

Specialiation of responses depends on the GPCR COUPLING MECHANISM! (i.e. which intracellular signaling pathways are activated)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Discuss M1 and M3 mAChR’s.

A

EXCITATORY RESPONSE

Phospholipase C causes release of intracellular Ca2+ (promoting contraction)!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Discuss M2 mAChR’s.

A

INHIBITORY RESPONSE

Muscle relaxation caused by an increased Kir conductance, or by inhibiting adenylate cyclase

(Go GPCR)

OR

(Gi GPCR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are mAChR’s inhibited by?

A

ATROPINE

(opposes normal parasymp. actions, THUS promoting a “sympathetic-like” effect)!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

In LOW DOSES, what effect does atropine cause?

A

Depresses salivary & bronchial secretions

17
Q

In MODERATE DOSES, what effect does atropine cause?

A

Dilates pupils

Vagal effects on heart blocked, THUS increase heart rate!

18
Q

In HIGH DOSES, what effect does atropine cause?

A

Inhibits gastric secretion & motility

19
Q

When OVERDOSED, what effect does atropine cause?

A

Hallucination

Delirium

Coma