ANS 1 Flashcards

1
Q

describe the organisation of the nervous system

A
  • CNS - brain and spinal cord
  • PNS - motor & sensory neurons, somatic and ANS divisions
  • ANS - parasympathetic vs sympathetic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the peripheral NS?

where are the cell bodies and peripheral nerves?

A
  • anything not in the brain or spinal cord
  • cell bodies are located in the spinal cord or in ganglia (collection of cell bodies)
  • peripheral nerves are either - somatic NS (sensory and motor nerves) or autonomic NS (controls smooth muscle and gland secretions and enteric NS)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the ANS and briefly describe what it controls

A
  • ANS controls multiple systems that maintain homeostasis
  • eg it controls blood pressure, metabolism, gut mobility, digestion, reproductive function etc
  • involuntary - subconscious
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what does the NTS stand for?

A

nucleus tractus solitarri - nuclei in the brainstem that receives many inputs from the cranial nerves

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

how are the efferent nerves organised in the ANS?

A
  • two distinct branches
  • pre and post ganglionic neurons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what 2 branches is the ANS divided into?

A
  • parasympathetic
  • sympathetic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe the parasympathetic system PNS

eg functions

A
  • rest and digest functions
  • GI acid secretion
  • GI motility - increases motility
  • pupil constriction and lens adjustment
  • heart rate - reduces
  • often overridden by the SNS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

describe the sympathetic NS

A
  • often described as ‘fight or flight’
  • functions include increasing the hr, airway dilation (bronchodilation), dilates pupil of eye, decreases gut motility and secretions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are the **3 different types of interaction **between the SNS and the PSNS?

A
  • **antagonistic **- act in opposing directions
  • **complementary **- both act similarly
  • co -operative - both play a role at some stage in overal function
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

describe the **antagonistic effects **of the SNS and PSNS

A
  • heart rate - SNS increases it and PNS decreases it
  • gut motility - SNS decreawes contraction and PNS increases contraction
  • pupil pf the eye - SNS dilates the pupil and PSNS constricts the pupil
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is an example of a **complimentary effect **of SNS and PNS?

A
  • saliva
  • primarily controlled by the PNS in response to various stimuli - eg if there is food in the mouth etc
  • SNS input changes the composition of saliva but not the volume made (makes it thicker and conatin more protein)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the **co-operative effects **of the SNS and PNS

2 examples

A
  1. **pupil of the eye and lens **
    * sns causes dilation of the pupil and pns causes focussing of the lens
  2. reproduction
    * PNS causes erection through the dilation of blood vessels
    * SNS causes ejaculation by constriction of smooth muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is a pre-ganglionic vs post ganglionic neuron?

A
  • pre-ganglionic neuron - cell body in the brain stem or spinal cord
  • post ganglionic neuron - collection of cell bodies outside the CNS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the anatomical definition of the SNS?

A
  • thoraco-lumbar (T1-L2)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the** anatomical definition** of the PSNS?

A
  • cranio-sacral
  • crain nerves III,VII,IX and X)
  • sacral segments S2-S4
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

describe the length of the pre and post ganglionic fibres in the PSNS

A
  • in the PNS, ganglia are **close to the target tissue **
  • therefore there are** long pre-ganglionic fibres**
    *** short post ganglionic fibres **
17
Q

describe the length of the pre and post ganglionic fibres in the SNS

A
  • fibres in the SNS are arranged in a **chain close to and on either side of the spinal cord **
  • short pre-ganglionic fibres
    * long post-ganglionic fibres
18
Q

what neurotransmitters do the post ganglionic fibres of the PSNS and the SNS release?

A
  • PNS post-ganglionic fibres release Ach
  • SNS post-ganglionic fibres release noradrenaline (NA)
  • NB - some SNS fibres tp sweatglands and pilorector muscles are cholinergic
19
Q

what do pre-ganglionic neurons of both the PNS & the SNS release?

A

Acetylcholine

20
Q

where are the adrenal glands located and what NT’s do they release & what area of the gland is an extension of the SNS & how?

A
  • the adrenal medulla of the adrenal glands is an extension of the SNS
  • adrenal glands sit next to the kidney (ad renal) and secrete catecholmines (NA & Adr) from the medulla
  • sympathetic pre-ganglionic fibres stimulate chromaffin cells in the medulla leading to release of adr and NA
21
Q

what is neural tone in the ANS?

A
  • it is not the case that the ANS is switched on or off as required
  • at rest, there is basal activity in both the SNS and PNS known as neural tone
  • ie the SNS tone keeps the blood vessels slightly constricted and the PNS tone keeps the HR under 100bpm
22
Q

what centre of the CNS is the site of cardio and resp control?

A
  • the brain stem - pons & medulla
  • they receive afferents from both baro and chemo receptors
23
Q

what is the function of the hypothalamus in terms of the ANS?

A
  • set point control in a number of negative feedback control systems including temperature, osmolality and hunger
24
Q
A