PHYSIO/ANAT - ANS Flashcards

1
Q

What are the 2 fuctnional divisions of the nervous system?

A
  • somatic NS
  • visceral NS
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2
Q

What does the visceral NS supply?

A

Internal organs/viscera

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3
Q

What are the divisions of the visceral NS?

A
  1. Visceral sensory/afferent
  2. Visceral motor/ ANS
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4
Q

What does the ANS innervate?

A

Smooth muscle
Cardiac muscle
Glands

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5
Q

What are the 2 divisions of the ANS?

A

-sympathetic
-parasympathetic

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6
Q

Is the ANS controlled voluntarily?

A

No

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7
Q

What is a main difference between the structure of the ANS and the somatic motor system?

A

Somatic motor system - cell body is in CNS and one axon extends to muscle

ANS - a chain of 2 neurons (pre and postganglionic neurons)

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8
Q

What is a ganglion?

A

A group of cell bodies

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9
Q

Where does the preganglionic neuron run from ? SYMPATHETIC

A

Spinal cord -> ganglion

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10
Q

Where does the postganglionic neuron run from? SYMPATHETIC

A

Ganglion -> organ

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11
Q

Where are the cell bodies of presynaptic neurons found? SYMP

A

In the lateral horns of spinal cord segments T1-L2/L3

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12
Q

Where do the preganglionic axons of symp. division exit the spinal cord from?

A

Anterior roots of spinal nerves

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13
Q

How do preganglionic axons of symp system separate from spinal nerves?

A

Separate as white rami communicantes

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14
Q

What do white rami of symp division enter ?

A

Sympathetic chains

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15
Q

In the sympathetic NS, where can the preganglionic neuron synapse?

A
  1. Paravertebral ganglia/sympathetic chain
  2. Preverterbral ganglia
  3. Adrenal medulla
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16
Q

Where is the sympathetic trunk located?

A

Anterolateral to vertebral column from skull to coccyx

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17
Q

Is there the same amount of ganglia in the sympathitic chain as there are spinal nerves? Why/why not?

A

No
The ganglia fuse

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18
Q

Where are the ganglia located on the sympathetic chain?

A

3 in cervical area
11 thoracic
4 lumbar
4 sacrall

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19
Q

How are ganglia of the sympathetic trunk connected?

A

By the interganglionic trunk

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20
Q

What are the 3 ways for the postganglionic neurons to travel to target organs? SYMPATHETIC - SYNAPSING IN CHAIN OF GANGLIA

A
  1. Exit in grey rami comminucans and travel with somatic nerves
  2. Associate with large arteries to travel to head
  3. Run directly to thoracic organs
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21
Q

How do postganglionic neurons which synapse in the sympathetic trunk exit the sympathetic trunk? SYMPATHETIC

A

Via grey rami communicans

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22
Q

When postganglionic neurons which synapse in the sympathetic trunk run with spinal nerves, what do they innvervate? SYMPATHETIC

A
  1. Sweat glands
  2. Arrector pili muscles
  3. Peripheral blood vessels
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23
Q

When postganglionic neurons which synapse in the sympathetic trunk run with large arteries, what do they innvervate?

A
  • salivary gland
  • smooth muscle
  • blood vessels in head
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24
Q

When postganglionic neurons which synapse in the sympathetic trunk run directly to organs, what do they innvervate?

A

Heart and lungs - THORACIC ORGANS ONLY

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25
Are the sympathetic presynaptic neurons which synapse in the prevertebral ganglia paired?
No
26
Where are sympathetic presynaptic neurons which synapse in the prevertebral ganglia found?
Only in abdomen and pelvis
27
Do sympathetic presynaptic neurons which synapse in the prevertebral ganglia go through the sympathetic chain?
Yes
28
How do sympathetic presynaptic neurons which synapse in the prevertebral ganglia reach the prevertebral ganglia?
By travelling in splanchnic nerves
29
Where are prevertebral ganglia located?
Abdominal aorta
30
Where are the ganglia of the parasympathetic division located?
In/near/on the target organ
31
Where are the cell bodies of the parasympathetic preganglionic neurons located?
- in brain stem - in lateral gray horns of S2-S4
32
What do the parasympathetic preganglionic axons which come from the brain travel through?
Cranial nerves - CN III - CN VII - CN IX - CN X (vagus nerve)
33
What do the parasympathetic preganglionic axons which come from the sacral region travel through?
Pelvic splanchnic nerves
34
Where does CN III synapse?
Ciliary ganglion
35
Where does CN VII synapse?
Pterygopalatine ganglion and Submandibular ganglion
36
Where does CN IX synapse?
Optic ganglion
37
Where does CN X synapse?
Various places in thorax and abdominal cavity
38
Where do preganglionic neurons which travel in pelvic splanchnic nerves synapse?
Inferior hypogastric plexus and Ganglia in pelvic viscera
39
Are preganglionic neurons in the sym NS long/short?
Short
40
Are preganglionic neurons in the parasym NS long/short?
Long
41
Are postganlionic neurons in the sym NS long/short?
Long
42
Are postganlionic neurons in the parasym NS long/short?
Short
43
What are the general/most common physiological effects of the symp NS?
Fight, flight, fright
44
What are the general/most common physiological effects of the parasymp NS?
Rest and digest
45
What are the 3 main anatomical differences between the sympathetic and parasympathetic divisions of the ANS?
- origin - ganglia location - length of fibre
46
Are organs only innverated by the parasympathetic division?
No. Most have dual innervations where the parasym and sym divisions have opposite effects.
47
What is the benefit of organs having dual innervation from parasym and sym NS?
Activities or the structures can be coordinated
48
What are the components of the reflex arc of the ANS?
- an afferent pathway - a central regulatory component - an efferent pathway
49
Where are the central regulatory components on the ANS located?
- spinal cord - hypothalamus - brain stem
50
What is the main integration centre for visceral sensory input? (Transmits sensory input into an effect carried to organ by sym or parasym pathways)
Hypothalamus
51
How do postganglionic nerve fibres of the ANS communicate with tissues?
They have varicosities which lie in close contact with the cells and release neurotransmitters
52
What is the site where varicostities come into contact with tissue cells called?
Neuroeffector junctions
53
What neurotransmitter is emitted from the sympathetic system?
Noradrenaline/norepinephrine
54
What family of chemicals to noradrenaline and adrenaline belong to?
Catecholamines
55
What is an adrenergic response?
When ANS pathways release noradrenaline into tissues
56
What is a cholinergic response?
When ANS pathways release ACh into tissues
57
Can parasympathetic nerve fibres release a wide range of neurotransmitters?
No - they only release ACh
58
What tissues do sympathetic pathways release ACh into?
Sweat glands, Arrector pili muscles, some blood vessels in skeletal muscle
59
What happens when neurotransmitters emitted by ANS pathways bind to receptors on cells in tissues?
It initiates an intracellular signalling cascade which results in the alteration of the cell phenotype
60
What are the 2 main signalling cascades caused by neurotransmitters emitted by ANS binding to cells?
- cAMP cascade (adenylyl cyclase) - phosphoinositide pathway
61
What is an agonist ?
Something which activates a receptor
62
What kind of receptors does noradrenaline bind to ?
Adrenergic receptors / adrenoceptos
63
What is another name for adrenergic receptors?
Adrenoceptors
64
What are the subtypes of adrenergic receptors?
α1, α2, β1, β2, β3
65
What is the significance of the subtype of adrenergic receptor which is present on an organ?
Norepinephrine can have excitatory/inhibitory effects depending on the subtype present on the organ
66
What do α-adrenoceptors activate/inhibit?
- activate phosphoinositide pathway pathway - inhibit cAMP cascade
67
What do β-adrenoceptors activate/inhibit?
Activate cAMP cascade
68
The subtypes of adrenergic receptors expressed in a tissue is a basis for drug production t/f?
True
69
What is an antagonist?
Binds to the receptor and blocks teh activity of the receptor
70
What does ACh bind to?
Cholinergic receptors
71
What are the 2 types of cholinergic receptor?
Nicotinic Muscarinic
72
What kind of receptors are located at the synapses between pre and postganglionic neurons in both sym and parasym divisions?
Nicotinic receptors
73
What kind of neurotransmitter is released by parasympathetic. Postganglionic neurons?
ACh
74
What does ACh released by parasympathetic Postganglionic neurons bind to ?
Muscarinic receptors
75
What are the subtypes of muscarinic receptor ?
M1-M5
76
What intracellular signalling pathways do cholinergic receptors generally activate/inhibit?
- activate phosphoinositide pathways - inhibit cAMP cascade
77
What happens when an organ is require to work at a different rate?
CNS coordinates ANS response to increase/decrease activity
78
What are the postganglionic cells of the adrenal medulla?
Chromaffin cells
79
What happens when chromaffin cells are stimulated ?
They release adrenaline
80
What % of chromaffin cells release adrenaline ino circulation ?
80%
81
What % of chromaffin cells release noradrenaline ino circulation
20%
82
What are the cardiovascular effects of adrenaline ?
- increase heart rate - increase cardiac output - raise blood pressure -vasodilate skeletal muscle blood vessels - vasoconstrict gastrointestinal, renal and splenic beds
83
How does adrenaline vasodilate smooth muscle blood vessels?
Adrenaline has a high affinity for beta 2 adrenergic receptors which trigger smooth muscle relaxation in blood vessels
84
How does adrenaline vasoconstrict gastrointestinal, renal and splenic beds?
Alpha 1 and alpha 2 adronergic receptors trigger smooth muscle contraction