Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

CVS 2023 > Autonomic nervous system > Flashcards

Autonomic nervous system Flashcards

1
Q

What does Autonomic Nervous System regulate?

A

Physiological functions

(e.g. Heart rate, temperature, BP)

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

Give some examples of the physiological functions that the ANS controls

A

– Heart rate, BP, body temperature… etc (homeostasis)
– Co-ordinating the body’s response to exercise and stress

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

In ANS regulation largely voluntary or involuntary?

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

What types of tissues does ANS exert control over? (3)

A
  • Smooth muscle (Vascular and visceral)
  • Exocrine secretion
  • Rate and force of contraction in heart (HR)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

2 divisions of ANS and what are these based on?

A

Sympathetic and Parasympathetic

Based on Anatomical grounds

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

Some text books include a 3rd division of the ANS, describe this

A
  • Enterinc nervous system
  • Network of neurones surrounding the GI Tract
  • Is normally controlled via sympathetic and parasympathetic fibres (mix of both)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the parasympathetic NS responsible for?

A

‘rest and digest’ / basal conditions

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

What is the sympathetic nervous system responsible for?

A

‘fight or flight’ / stressful conditions (can be coordinated or independent in diff. tissues)

(s for stress and sympathetic)

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

Sympathetic ganglionic arrangement

A

Short preganglionic neurone

Long post ganglionic neurone to target tissue

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

Parasympathetic ganglion organisation

A

Long preganglionic neurone

Short postganglionic neurone (within target tissue walls)

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

What happens under stress?

A

Sympathetic system activity is increased

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

What autonomic system is more dominant under normal body conditions (basal)?

A

PNS - dominates under normal circumstances

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

What is the anatomical origin of the SNS?

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

What is the anatomical origin of the PNS?

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

What do preganglionic neurones of both PNS and SNS divisions release?

A
  • Acetylcholine (ACh)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does the acetylcholine released from the preganglionic neurones act on?

A
  • Nicotinic acetylcholine receptors on the postganglionic cell (neuromuscular junction)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What do nicotinic MACh receptors have?

A
  • An Ion channel
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe how action potentials are fired to act on the effector cells

A
  • Pre ganglionic neurone fires action potentials
  • Causes release of acetylcholine from the terminal
  • They act on the nicotinic acetylcholine receptors at the neuromuscular junction
  • These receptors have an integral ion channel
  • The acetylcholine binds to the receptor
  • This opens the ion channel
  • The ion channel is permeable to sodium and potassium ions but at resting membrane potentials, overwhelming you get an inward movement of sodium ions
  • This depolarises the post ganglionic neurone to threshold
  • And it can then fire action potentials
  • The postganglionic neurone then releases a neurotransmitter (noradrenaline) onto the effector cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where are preganglionic cell bodies found in?

A
  • CNS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the primary neurotransmitter in the parasympathetic neurotransmitter?

A

Acetylcholine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where are preganglionic synapses found?

A
  • Periphery
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What receptor does sympathetic system usually act on and how?

A

Adrenaline/noradrenaline released and acts on Adrenergic receptors (eg a1/b1 or b2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What receptor does parasympathetic system usually act on and how?

A

Ach binds to muscarinic receptors usually (eg M3/M2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What happens if you denervate a heart?

A

Still beats but faster

Vagal influence from parasympathetic usually slows down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Parasympathetic supply to heart is via...
Preganglionic fibres of Vagus nerve (10th cranial nerve)
26
Where do preganglionic fibres synapse to postganglionic fibres in parasympathetic system?
On epicardial surface/within heart (SA/AV NODE!)
27
What do post ganglionic fibres release in parasympathetic heart stimulation and what does this bind to?
Ach | Binds to M2 receptors
28
Effects of Ach binding to M2 receptor
``` Decrease HR (-ve chronotropic effect) Decrease AV node conduction velocity ```
29
Sympathetic input to heart
Postganglionic fibres travel from sympathetic chain
30
What do the post ganglionic fibres of sympathetic system innervate?
SA NODE, AV NODE, MYOCARDIUM | different to parasympathetic as myocardium is included here
31
How does the sympathetic input occur in heart?
Release of Noradrenaline | NA binds to B1 adrenoreceptors
32
What effect does NA binding to B1 adrenoreceptors have on the heart?
``` Increase HR (+ve chronotropic effect) Increase force of contraction (+ve inotropic effect) ```
33
What sets the rhythm of the heart?
AP firing in the SA node (steadily depolarise towards threshold)
34
Sympathetic effects on AP firing in SA node
Noradrenaline binds to B1 receptors (Gs receptors) Increase cAMP Speeds up pacemaker potential (If - funny current)
35
Parasympathetic effects on AP firing SA node
Ach binds to M2 receptors (Gi receptors) Decrease cAMP Increase K+ conductance decreases pacemaker potential slope
36
How does noradrenaline increase force of contraction?
NA acts on B1 receptors Increase cAMP Activates PKA = phosphorylation of Ca2+ channels
37
What does phosphorylation of Ca2+ channels lead to?
Increase Ca2+ entry during plateau | Increase uptake of Ca2+ in SR (more available to release)
38
what innervation type do most vessels receive?
Sympathetic
39
What receptors are present in most vessels?
a1 adrenoreceptors
40
What vessels have B2 receptors?
skeletal muscle myocardium liver
41
What do you need to ensure you can have vasoconstriction and vasodilation?
Vasomotor tone | Already some constriction to allow vasodilation if needed
42
How does sympathetic output effect vessels?
Increased output = vasoconstriction | decreased output = vasodilation
43
How does circulating adrenaline affect vessels?
High affinity for b2 receptors than for a1 | At high levels adrenaline can affect a1
44
What binds to what to allow for vasoconstriction/vasodilation?
More Noradrenaline will bind to a1 | adrenaline binds to b2 but a1 in high levels
45
What effect does activating b2 adrenoreceptors have?
Vasodilation
46
What effect does activating a1 adrenoreceptors have?
Vasoconstriction
47
How does vasodilation occur from activating b2 receptor?
``` Increase cAMP PKA Open K+ channels inhibits MLCK (cannot phosphorylate MLC) Relaxation of smooth muscle ```
48
How does vasoconstriction occur from activation of a1 receptor?
IP3 production Increase in Ca2+ from SR stores and influx = Contraction (DAG inhibits MLC phosphatase so stays phosphorylated)
49
What has the largest impact on ensuring adequate perfusion?
``` Metabolite concentration (eg adenosine, H+) STRONG vasodilator effect ```
50
How are changes in system communicated to brain?
``` Afferent nerves (towards brain) eg baroreceptors or atrial receptors ``` this then alters efferent pathway
51
What are baroreceptors?
``` Stretch receptors (increased arterial pressure = stretch) ```
52
Where are baroreceptors found?
Carotid sinus and aortic arch
53
What happens if baroreceptors detect stretch of blood vessels?
Stretch = high BP Fire more action potentials towards medulla Inhibit SNS, Activate PNS =Bradycardia and Vasodilation
54
What is baroreceptor for?
Maintaining blood pressure over SHORT time | moment to moment
55
What happens to baroreceptors if there is continuous hypertension?
Reset to 'new normal' | reset to higher levels
56
drugs acting on ANS
Sympathomimetics (a and b receptor agonists) Adrenoreceptor antagonists Cholinergics (muscarinic antagonists/agonists)
57
Sympathomimetics eg
Adrenaline Dobutamine salbutamol
58
Adrenaline function
Restore function and support circulation in cardiac arrest Anaphylactic shock (you get widespread vasodilation when this occurs, HIGH LEVELS of adrenaline stimulates a1 receptor)
59
Dobutamine
``` B1 agonist cardiogenic shock (pump failure) ```
60
Salbutamol
``` b2 agonist treats asthma (relaxes bronchioles0 ```
61
a adrenoreceptor antagonists
Anti-hypertensive eg a1 antagonist PRAZOSIN Inhibits NA action on a1 receptors = vasodilation
62
B adrenoreceptor antagonists example
Propranolol = non selective slows HR reduce force of contraction but BRONCHOCONSTRICTION
63
problem with propranolol
non selective NOT GOOD for Asthmatic patient (causes bronchoconstriction from b2) (use selective b1 like atenolol)

CVS 2023 (26 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions