COM 2 physiology Flashcards
(79 cards)
1
Q
Name the visceral functions that the ANS controls
A
- Arterial pressure
-Sweating and bidy temperature regulation
-Gastrointestinal motility
2
Q
What is the ANS activated mainly by
A
- Centers in the spinal cord, brain stem and hypothalamus
- Higher brain areas
3
Q
What does the ANS operate through
A
Visceral reflexes
4
Q
What is the ANS divided into
A
- Sympathetic nervous systen
-parasympathetic nervous system
5
Q
What does the sympathetic nervous system orignate from
A
Spinal cord segmenta T1 to L2
6
Q
What does the sympathetic nervous system include
A
- paravertebral sympathetic chains
-prevertabral ganglia - nerves exteneded from ganaglia to organs
7
Q
In the sympathetic Nervous system where does the cell body of the preganglionic neuron lie + postganglionic neuron
A
-preganglionic neuron: Cell body in intermediolateral horn of spinal cord
-postganglionic neuron : Cell body in ganglion
8
Q
What is the distribution of the sympathetic nerves based on
A
- Embryological origin of organs
9
Q
what do T1 send fibers to
A
Upward to the head
10
Q
What do T2 send fibers to
A
Neck
11
Q
What do T3-T6 send fibes to
A
Thorax
12
Q
What do T7 - T11 send fibers to
A
Abdomen
13
Q
What do T12 -L2 send fibers
A
Downwards to the legs and pelvic organs
14
Q
What do the parasympathetic fibers leave the central nervous system through
A
- Cranial nerves, 3,7,9,10
and sacral spinal nerves S2, S3 and sometimes S1 and S4
15
Q
What do parasympathetic pathways use
A
- preganglionic and postganglionic neurons
16
Q
What is the structure of preganglionic fibers in parasympathtic fibers
A
- LONG
17
Q
In the PSN where is the postganglionic neurons located
A
- within the wall of the target organ
18
Q
What is the name for cranical nerve 3 + what does it contribute to
A
- oculomotor
- To the pupillary sphincter and ciliary muscle of they eye
19
Q
What is the name of cranial nerve VII
A
Facial nerves
20
Q
What does the cranial nerve VII (7) contribute to
A
- Lacrimal, nasal and submandibular glands
21
Q
What is the name of cranial nerve IX -9
A
Glossopharyngeal
22
Q
What does the cranial nerve IX - 9contribute to
A
- Partoid gland
23
Q
What is the name for cranial nevre X
A
Vagus
24
Q
What does the cranial nerve X, vagus contribute to
A
-Heart , lungs, esophagus, stomach, intestines
25
What does the sacral nerves (Pelvic nerves) contribute to
- Descendign colon, rectum, bladder
26
Name the neurotransmitters both sympathetic and parasympathetic systmes use
- Acetylcholine and norepinephrine
27
What do cholinergic fibers secrete
Acetylcholine
28
What do adrenergic fibers secrete
Norepinephrine and epi ephrine in the adrena medulla
29
Are all preganglionic neurons cholinergic or adrenergic
Cholinergic
30
What does ACh stimulate im both systems
- Sympathetic and parasympathetic postganglipnic neurons
31
What are sympathetic postganglionic neurons are mostly...
Adrenergic
32
Parasympathetic postganglionic neurons are mostly...
cholinergic
33
Exp;ain the process starting from an action potential how neurotransmitters are released
Action potential → depolarization of nerve endings → increased calcium permeability → calcium entry → release of neurotransmitter (ACh or NE) from vesicles.
34
Where is ACh synthesized and from what
in the nerve endings
choline + acetyl coA =ACh via choline acetyltransferase
35
What is ACh broken down by and what is it broken down into
- Acetylcholinesterase
- into acetate and choline
36
Where does norepinephrine synthesis occur
Axoplasm of adrenergic nerve terminals
37
Explain the steps invlolved in norepinephrine synthesis
Key steps:
Hydroxylation of Tyrosine → Forms Dopa.
Decarboxylation of Dopa → Forms Dopamine.
Dopamine is transported into secretory vesicles.
Hydroxylation of Dopamine inside vesicles → Forms Norepinephrine (NE).
38
Where does epinephrine synthesis occur
Adrenal medulla
39
Explain the steps of epinephrine synthesis
same as norepinephrine + one additional step.
Key steps:
Hydroxylation of Tyrosine → Forms Dopa.
Decarboxylation of Dopa → Forms Dopamine.
Dopamine is transported into secretory vesicles.
Hydroxylation of Dopamine inside vesicles → Forms Norepinephrine (NE).
5. Methylation of Norepinephrine → Forms Epinephrine (E).
40
Explain the process of removal after secretion of the neurptransmitters( norepinephrine+ epinephrine)
Reuptake into nerve endings (50–80% of NE).
Diffusion into surrounding fluids and blood.
Destruction by enzymes: monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT).
41
Before ACh, NE and E can stimulate an organ what must happen
It needs to bind to specific receptors
42
What does binding of the neurotransmitter to the receptors cause
- A confirmational change which can :
- Change membrane permeablitity to ions
-Activate or inactivate an intracellular enzyme
43
What may the binding of neurotransmitters do inrelation to ionchanngels
May:
Open Na⁺ or Ca²⁺ channels → Depolarization and excitation.
Open K⁺ channels → Hyperpolarization and inhibition.
Allow Ca²⁺ influx to directly trigger actions,
44
What is the function of the enzyme cAMP
Triggers various intracellular effects
45
What does the response of a neurotransmitter depend on - 3/4
- Type of receptor protein
-The Conformational chnage caused by the neurotransmitter binding
-The type of effector cell and its chemical machinery
46
Name the 2 major classes of adrenergic receptors
- Alpha receptors
-Beta receptors
47
Name the subtypes of the alpha receptors + what it is linked to
-a1+ a2
-linked to different G proteins
48
Name the subtypes of the beta receptors + what does it use
- B1, B2, B3
-Uses a G protein signaling
49
What is the effect of norepinephrine on alpha and beta receptors
Excites mainly alpha receptors + lesser beta receptors
50
What is the effect of epinephrine
Exictes both alpha and beta receptors
51
Name the 2 types of Acetylcholine receptors
- Muscarinic + Nicotinic receptors
52
What is muscarinic receptors activated by
MUSCARINE
53
Where are muscarinic receptors found
- On effector cells
54
What are muscarinic receptors stimulated by
Postganglionic cholinergic neurons
55
What is nicotinic receptors activated by
Nicotine
56
Where is nicotinic receptors found
- At autonomic ganglia and neuromuscular junction
57
What system has its own intramural plexus( eneteric nervous system)
- Gastrointestinal system
58
Explain the affect of parasympathetic and sympathetic stimulation on the gastrointestinal systems
PARASYMPATHETIC : -Increase gut activity
Sympathetic - inhibits gut activity
59
What does sympathetic stimulation of adrenal medulla release
80%epinephrine and norepinephrine20%
60
What are the effects of norepinephrine
- Constricts blood vessels
-Increases heart activity
-Inhibits gastrointestinal tract
-Dilates pupils
61
What are the effects of epinephrine comparedd to norepinephrine
- Stronger cardiac stimulation
-Weaker vasoconstriction
Greater metabolic effects
62
What does weaker vasoconstriction result in
-Smaller increase in arterial pressure
-Greater increases in cardiac output
63
What system does adrenal medullae support
Sympathetic nervous system
64
What does the adrenal medulla provide for the sympathetic nervous system
Provides direct nerve stimulation and indirect hormone mediated stimulation
65
What is a low stimulation frequency needed for
- Full autonomic effect
66
What is tone?
Continous basal activty of autonomic systems
67
What is the function of sympathetic tone+ what can it cause
-Keeps the systemic arterioles constricted
-Can cause vasoconstriction
68
What does parasympathetic tone maintain
Gut motility and function
69
What does cutting the vagus nerves result in
- Gastric and intestinal atony (loss of tine) leading to constipation
70
What does cutting autonomic nevres result in
Loss of tone
71
Does gastrointestinal tone have long or short long lasting impacts
- Long lasting impacts
72
After a sympathtic or parasympathetic nerve is destroyed what happens to the sensitivity of the target organ
Target organ becomes more sensitive to injected neurotransmitters
73
What is the increased sensitivity to neurotransmitters called
- Denervation supersensitivity
74
What does the cardiovascular (baroreceptor reflex) inhibit and activate
- Inhibites sympathetic impulses to the heart and ACTIVATES parasympathetic impulses, lowering blood pressure
75
What does the gastrointestinal reflex trigger
- Triggers vagal and glossopharyngeal nuclei
76
What is sexual reflexes initiated by
- By both brain and local stimuli
77
What are all the effects that happen in the fight or flight response
- Increases blood pressure
-Increased metabolism and glucose
-Increases blood clotting
-Enhanced muscle strength
78
What is autonomic functions controlled by
- Neurons in the medulla, pons and mesencephalon
79
What does a transection below the medulla drop?
-It drops arterial pressure
