Autonomic nervous system Flashcards
1
Q
What are the 2 major components of the nervous system?
A
- Central nervous system (CNS)
- Peripheral nervous system (PNS)
2
Q
What is the central nervous system?
A
Brain and spinal chord
3
Q
What are the 2 major components of the peripheral nervous system?
A
- Somatic
- Autonomic
4
Q
What does the somatic nervous system control?
A
Voluntary control of the skeletal muscles
5
Q
What does the autonomic nervous system control?
A
Involuntary control of smooth muscle, cardiac muscle, glands etc.
6
Q
What are the 2 components of the autonomic nervous system?
A
- Sympathetic
- Parasympathetic
7
Q
What does the sympathetic nervous system do?
A
Fight or flight
8
Q
What does the parasympathetic nervous system do?
A
Rest and digest
9
Q
What does sympathetic stimulation do to the heart? (2)
A
- Increase heart rate
- Increase heart contractility
10
Q
What does sympathetic stimulation do to the eyes?
A
Pupils dilate
11
Q
What does sympathetic stimulation do to the blood vessels? (2)
A
- Dilates blood vessels supplying skeletal muscles
- Constricts blood vessels supplying digestive system
12
Q
What does sympathetic stimulation do to the lungs? (2)
A
- Increases lung expansion
- Relaxes smooth muscle in the respiratory system to widen the airways
13
Q
What does sympathetic stimulation do to the liver?
A
Glycogen broken down and released as glucose
14
Q
What does sympathetic stimulation do to the reproductive system?
A
Essential for orgasm/ejaculation
15
Q
What does parasympathetic stimulation do to the eyes?
A
Pupils constrict
16
Q
What does parasympathetic stimulation do to the heart?
A
- Heart rate slows down
- No effect on contractility
17
Q
What does parasympathetic stimulation do to the GI tract? (2)
A
- Increases blood flow to GI tract
- Glands stimulated to secrete saliva, enzymes, bile etc.
18
Q
What does parasympathetic stimulation do to the bladder? (3)
A
- Bladder wall contracts
- Urinary sphincter relaxes
- Allows for urination
19
Q
What does parasympathetic stimulation do to the reproductive system?
A
Needed for arousal
20
Q
Which parts of the body are innervated by the sympathetic nervous system only? (4)
A
- Sweat glands
- Hair follicles
- Vascular smooth muscle
- Adrenal medulla
21
Q
How are blood vessels controlled by sympathetic nerves?
A
- Increased firing causes constriction
- Decreased firing causes dilation
- No parasympathetic innervation
22
Q
What is a peripheral ganglion
A
A cluster of neuronal cell bodies outside of the CNS
23
Q
What is a nucleus (of neurones)?
A
A cluster of neuronal cell bodies inside the CNS
24
Q
What is the general organisation of the ANS?
A
- Preganglionic neuron from the CNS sends axon to the ganglion
- Synapses onto a postganglionic neuron which sends axon to target cell
25
What kind of neurones are ANS preganglionic neurones?
Always cholinergic
26
What kind of receptors are on ANS postganglionic neurones?
Nicotinic
27
What kind of neurones are sympathetic postganglionic neurones?
Noradrenergic
28
What do sympathetic postganglionic neurones release?
Noradrenaline
29
Which receptors are on the target cells of sympathetic postganglionic neurones?
Alpha/beta adrenergic receptors
30
What kind of receptor are adrenergic receptors?
Metabotropic
31
Where do the preganglionic sympathetic neurones originate? (2)
Thoracic and lumbar regions of spinal chord
32
How long is the sympathetic preganglionic neuron?
Short
33
How long is the sympathetic postganglionic neuron?
Short
34
What are the inner sections of the adrenal gland?
- Adrenal cortex (outside)
| - Adrenal medulla (inside)
35
How does the sympathetic nervous system cause the release of adrenaline?
- Presynaptic neuron reaches adrenal medulla which acts as a modified postganglionic neuron
- Adrenal medulla cells release adrenaline which enters the bloodstream
36
Where is adrenaline released from?
Adrenal glands
37
Which cells in the adrenal medulla release adrenaline?
Chromaffin cells
38
What do chromaffin cells do?
Release adrenaline from the adrenal medulla
39
How long is the parasympathetic preganglionic neuron?
Long
40
How long is the sympathetic postganglionic neuron?
Short
41
Where do the preganglionic parasympathetic neurones originate? (2)
Brainstem and sacral region of spinal chord
42
What kind of neurones are parasympathetic postganglionic neurones?
Cholinergic
43
What do parasympathetic postganglionic neurones release?
Acetylcholine
44
Which receptors do parasympathetic postganglionic neurones activate on target cells?
Muscarinic
45
Which part of the nervous system does the vagus nerve belong to?
Parasympathetic
46
Where does the vagus nerve come from?
Brainstem
47
What is an afferent neurone?
Receives information from organs etc. and transmits it to CNS
48
What is an efferent neurone?
Sends impulses from CNS to organs etc.
49
Where in the spinal chord are preganglionic neurones located?
Lateral horn
50
Which preganglionic neurones are located in the brainstem?
Parasympathetic
51
What does the hypothalamus regulate? (5)
- Feeding
- Thermoregulation
- Circadian rhythms
- Sex drive
- Reproduction
52
Which are the 2 main neurotransmitters in the ANS?
- Acetylcholine
| - Noradrenaline
53
Which G protein are M1, M3 and M5 (muscarinic receptors) coupled to?
Gq
54
What happens when a ligand binds to a receptor coupled to Gq?
- Increases PLC action
- Increased production of IP3 and DAG
- Rise in intracellular calcium
55
Where are M3 receptors found?
Endothelial cells
56
What is the function of M3 receptors on endothelial cells?
Regulates NO production
57
What does NO do to blood vessels?
- Causes vasodilation
| - Leads to drop in blood pressure
58
Which G protein are M2 and M4 (muscarinic receptors) coupled to?
Gi
59
What happens when a ligand binds to a receptor coupled to Gi?
- Inhibits adenylyl cyclase
- Lowers production of cAMP
- Opens GIRK channels (K+)
- Closes Ca+ channels
60
Where are M2 mainly receptors found?
Heart:
- Pacemaker cells
- Atrial muscle
61
What does activation of M2 receptors do to the heart? (2)
- Opens GIRK channels which causes hyperpolarisation = slowing of heart rate
- Decreases cAMP and activity of PKA which causes decreased phosphorylation of Ca2+ channels = decreased contractility
62
Where are M1 and M3 receptors found?
Smooth muscle
63
What does activation of M1 and M3 receptors on smooth muscle cause?
- Rise of intracellular calcium
| - Causes muscle contraction
64
What does activation of M1 and M3 receptors on glands cause?
Secretion
65
What symptoms are caused by consumption of muscarine? (4)
- Drop in blood pressure (endothelial action)
- Increased saliva, tears, sweating (secretion effects)
- Abdominal pain (gut muscle contraction)
- Death from cardiac (slows heart rate) and respiratory failure
66
Which drug is a selective agonist for M3 receptors?
Cevimeline
66
Which drug is a selective agonist for M3 receptors?
Cevimeline
67
What is Cevimeline used to treat?
Dry mouth and eyes caused by Sjogren's syndrome (autoimmune disorder)
68
What is pilocarpine used to treat?
Glaucoma
69
What is glaucoma?
Build up of pressure in the eye
70
Which muscarinic receptors does atropine work on?
All 5 (non-selective)
71
What is atropine an antagonist for?
Muscarinic receptors
72
What does consumption of atropine cause? (2)
- Inhibition of secretion
| - Relaxation of smooth muscle
73
Is muscarine an agonist or antagonist?
Agonist
74
Is atropine an agonist or antagonist?
Antagonist
75
What is pirenzepine used to treat?
Peptic ulcers
76
Which receptor is pirenzepine an antagonist for?
M1
77
Which drug is a selective antagonist for M1 receptors?
Pirenzepine
78
Which receptor is cevimeline an agonist for?
M3
79
Which drug is a selective antagonist for M3 receptors?
Darifenacin
80
Which receptor is darifenacin an antagonist for?
M3
81
What is darifenacin used to treat?
Overactive bladder/incontinence
82
What are cholinomimetic drugs?
Drugs which mimic the effects of activating cholinergic signalling
83
How do cholinomimetic drugs work?
- Inhibit acetylcholinesterase which increases levels of ACh
| - Increases signalling through nicotinic and muscarinic receptors
84
What is physostigmine?
Anticholinesterase drug (cholinomimetic)
85
What is physostigmine used to treat?
Glaucoma
86
Which drugs are used in nerve gases?
Anticholinesterases
87
Which receptors are used by parasympathetic postganglionic neurones?
Muscarinic ACh receptors
88
Which receptors are used by sympathetic postganglionic neurones?
Alpha/beta adrenoreceptors
89
Where is adrenaline released from?
Chromaffin cells in the adrenal medulla (adrenal glands)
90
What kind of receptors are alpha/beta adrenoreceptors
Metabotropic (G-protein coupled)
91
What does activation of alpha 1 adrenoreceptors cause?
Vasoconstriction (blood vessels)
92
What does activation of beta 2 adrenoreceptors cause? (2)
- Vasodilation
| - Relaxation of airway smooth muscle
93
What does activation of beta 1 adrenoreceptors cause? (2)
- Increased heart rate
| - Increased contractility
94
Where are beta 1 adrenoreceptors found?
Heart
95
Where are beta 2 adrenoreceptors found?
Bronchi
96
Which G protein are alpha 1 adrenoreceptors coupled to?
Gq
97
Which G protein are alpha 2 adrenoreceptors coupled to?
Gi
98
Which G protein are beta adrenoreceptors coupled to?
Gs
99
Which drug is a selective agonist for alpha 2 adrenoreceptors?
Clonidine
100
Which drug is a selective agonist for beta 2 adrenoreceptors?
Salbutamol
101
What is the effect of Salbutamol?
Bronchodilation
102
What does activation of beta 1 adrenoreceptors cause?
- Increased activity of adenylyl cyclase
- Increase of cAMP
- cAMP activates PKA
- PKA phosphorylates Ca2+ channels
- Increased contraction in heart
103
How does ephedrine work?
Causes release of noradrenaline which constricts smooth muscle on nasal arteries to stop congestion
104
What are sympathomimetic drugs?
Drugs which mimic the effects of increased sympathetic signalling
105
What are alpha 1 selective antagonists used to treat?
Hypertension
106
Which drug is an alpha 1 selective antagonist?
Prazosin
107
What is Prazosin used to treat?
Hypertension
108
What are adrenoreceptor antagonists used to treat? (3)
- Hypertension
- Heart failure
- Anxiety
109
What are beta blockers used to treat?
- Heart failure
| - Anxiety
110
What are examples of beta blockers? (2)
- Carvedilol
| - Propranolol
111
What is propranolol used to treat?
Anxiety
112
How are beta blockers dangerous for asthma patients?
- Beta 2 activation causes bronchodilation
| - Blocking beta 2 would cause bronchoconstriction
113
What are unwanted side effects of beta blockers?
- Bronchoconstriction
- Cardiac depression
- Bradycardia
- Fatigue
- Cold extremities (vasodilation causes poor circulation)
114
What is bradycardia?
Slow heart rate
115
What is tachycardia?
Fast heart rate
