4. Autonomic Nervous System Flashcards

1
Q

Compare control of SNS and ANS

A

SNS: voluntary
ANS: involuntary

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

Compare number of neurons in pathway of SNS and ANS

A

SNS: single motorneuron
ANS: a preganglionic and postganglionic neuron

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

Compare cell body location of SNS and ANS

A

SNS: CNS
ANS: CNS for preganglionic and autonomic ganglion for post ganglionic

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

Compare effectors of SNS and ANS

A

SNS: skeletal muscle
ANS: cardiac muscle, smooth muscle, glands

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

Compare NTs and receptors of SNS and ANS

A

SNS: ACh/AChR
ANS: Preganglionic neuron: ACh/nAChR; postganglionic neuron: ACh/mAChR and NE/a1, a1, b1, b2

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

Divisions of autonomic nervous system

A

Sympathetic: ‘fight or flight’ (e.g. the body responds to fear, a difficult exam, a burning house, or an attacker)

Parasympathetic: ‘rest-and-digest’ (e.g. sexal arousal, salivation, lacrimation, urination, digestion, and defecation)

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

Describe the two neurons in series that connect the spinal cord and effector organs of the sympathetic division

A

Cell bodies of preganglionic sympathetic neurons are in thoracic and lumbar regions of spinal cord (T1-L3)
Thoracolumbar
Cell bodies of postganglionic sympathetic neurons are in:
-Paravertebral ganglia (sympathetic chain)
-Prevertebral/collateral ganglia (celiac, superior and inferior mesenteric ganglia)
Length of axons: short pre-ganglionic and long post-ganglionic

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

Adrenal gland

A

A speicalized sympathetic ganglion
Cell bodies of preganglionic located in thoracic spinal cord (T5-T9)
The axon of preganglionic neurons pass through the sympathetic chain and the celiac ganglion without synapsing, and travel to adrenal medulla, where they synapse on chromaffin cells

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

Endogenous analgesia system

A

Includes the secretion by the brain of endorphins in response to the central perception of pain.
Opioids and serotonin/catecholamines come from adrenal gland

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

Describe two neurons in series that connect the spinal cord and effector organ in the parasympathetic division

A

Cell bodies of preganglionic parasympathetic neurons are in nuclei of cranial nerves (III, VII, IX, X) and sacral region of spinal cord (S2-S4).
Craniosacral
Cell bodies of postganglionic parasympathetic neurons are within or very close to effector organs.

Length of axons: long pre-ganglionic axon; short post-ganglionic axon.

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

Sympathetic vs parasympathetic: origin of preganglionic nerve

A

Sympathetic=thoracolumbar

Parasymapthetic=craniosacral

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

Sympathetic vs parasympathetic: location of ganglia

A

Sympathetic=far from effector organs

Parasymapthetic=near or within effector organs

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

Sympathetic vs parasympathetic: length of preganglionic nerve

A

Sympathetic=short

Parasymapthetic=long

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

Sympathetic vs parasympathetic: length of post ganglionic nerve

A

Sympathetic=long

Parasymapthetic=short

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

Neuromuscular junction

A

The junction between motoneuron and its effectors (skeletal muscle fibers)
Motor end plate
Nerve terminals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Neuroeffector function

A

The junction between postganglionic autonomic neurons and its effectors (target tissues)
Branching networks
Varicosities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Neuroeffector junction vs. Neuromuscular junction: arrangement

A

neuroeffector junction = diffuse, branching networks

neuromuscular junction= discrete, organized structure called motor end plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Neuroeffector junction vs. Neuromuscular junction: innervation

A

neuroeffector junction = target tissues may be innervated by many postganglionic neurons
neuromuscular junction= a skeletal muscle fiber is innervated by a single motorneuron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Neuroeffector junction vs. Neuromuscular junction: NT storage sites

A

neuroeffector junction = varicosities

neuromuscular junction= nerve terminals

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

Neuroeffector junction vs. Neuromuscular junction: postsynaptic receptors

A

neuroeffector junction = postsynaptic receptors are widely distributed on the target tissue
neuromuscular junction= postsynaptic receptors are located in the specialized motor end plate

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

Adrenergic neurons

A

Synthesize and release norepinephrine

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

Adrenoreceptors

A

a1, a2, b1, b2; activated by NE or epinephrine

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

Cholinergic neurons

A

neurons that synthesize and release ACh

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

Cholinoreceptors

A

Nicotinic AChR, muscarinic AChR; activated by ACh

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Similarities of ACh in both ANS divisions

A

Preganglionic neurons release ACh that activates nAChR on postganglonic neurons in both sympathetic and parasympathetic divisions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

A substantial amount of nicotine (nAChR agonist) will cause…

A

Increase parasympathetic AND sympathetic response.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Non-classic neurotransmitters in parasympathetic division

A

VIP (vasoactive intestinal peptide)

NO (nitric oxide)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Non-classic neurotransmitters in sympathetic division

A

ATP

Neuropeptide Y

29
Q

In the ganglia, which transmitters and receptors are used in the parasympathetic, sympathetic and adrenal medulla?

A

ACh = transmitter

nAChR=receptor

30
Q

In the effector organs, which transmitters and receptors are used in the parasympathetic, sympathetic, and adrenal medulla

A

Parasympathetic:
ACh (VIP, NO) = transmitter
mAChR=receptor

Sympathetic:
NE, ACh (ATP, neuropeptide Y) = transmitter
a1, a2, b1, b2, mAChR =receptor

Adrenal medulla:
NE and epinephrine = transmitter
a1, a2, b1, b2=receptor

31
Q

G protein linked receptors

A

Activate G proteins (GDP to GTP)
Seven TM domains
Ex: adrenoreceptors (a1, a2, b1, b2) mAChRR

32
Q

G protein

A

Guanosine nucleotide-binding proteins
Heterotrimer (a, b, g)
Molecular switches: GTP (active) / GDP (inactive)
Activated by G protein-linked receptors

33
Q

Steps of G protein activation

A
  1. Inactive state
  2. Ligand binding
  3. Nucleotide exchange
  4. Active state
  5. Ligand-dissociation GTP hydrolysis
34
Q

Downsteam effects of G protein activation

A

Gs, Gi: activates or inhibits Adenylyl cyclase (AC) → cAMP↑ or ↓ → PKA ↑ or ↓

Gq: activates Phospholipase C (PLC) → inositol-1,4,5-triphosphate (IP3) ↑, diacylglycerol (DAG) ↑ → Ca2+↑ and PKC ↑

Direct alters the function of ion channels: mAChR → Gi → K+ channels of the sinoatrial node

35
Q

A1 receptor location

A

Vascular smooth muscle of the skin, skeletal muscle, and the splanchnic region
Sphincters of the gastrointestinal tract and bladder
Radial muscle of the iris.

36
Q

A1 receptor function

A

Activation leads to contraction

37
Q

A2 receptors and G protein

A

Adenylyl cyclase, but activates Gi protein, causes inhibitory effect – relaxation

38
Q

A1 receptors and G protein

A

Gq activates phospholipase C upon norepinephrine binding (alpha subunit with GTP binding lead to activation of phospholipase C) – skin and skeletal muscle, cause tissue contraction

39
Q

B1/B2 receptors and G protein

A

Norepinephrine binding, beta receptor activated… - in sinoatrial node and atrioventricular, increase heart rate, conduction velocity and contractility of heart muscle, increase lipolysis, saliva (beta1)

40
Q

B1 location

A

Sinoatrial (SA) node, atrioventricular (AV) node, and ventricular muscle of the heart
Salivary glands, kidney, and adipose tissue

41
Q

B2 location

A

Vascular smooth muscle of skeletal muscle
Walls of the gastrointestinal tract and bladder
Bronchioles

42
Q

B1 receptor function

A

Increase heart rate, conduction velocity, and contractility

Increase secretion of saliva, renin, and lipolysis

43
Q

B2 receptor function

A

Relaxation or dilation

44
Q

A2 receptor location

A

Vascular smooth muscle of certain blood vessels

Gastrointestinal tract

45
Q

A2 receptor function

A

Relaxation

46
Q

Autoreceptors

A

Present on sympathetic presynaptic regions
Inhibits further release of norepinephrine from the same terminals
Negative feedback
Are presynaptic a2 receptors

47
Q

Heteroreceptors

A

Present on parasympathetic presynaptic regions
Inhibits release of acetylcholine from the parasympathetic postganglionic nerve terminals.
Are presynaptic a2 receptors

48
Q

Why does Curare (nAChR blocker) cause relaxation of skeletal muscle?

A

Curare blocks nAChR that is required for the initiation of action potential and muscle contraction.

49
Q

Why does Atropine (mAChR blocker) increases heart rate?

A

Atropine inhibits mAChR and parasympathetic division, countering the “rest and digest” activity.

50
Q

Action of a1 adrenoreceptors

A

Stimulation of phospholipase C → ↑ IP3 → ↑ intracellular [Ca2+]

51
Q

Action of a2 adrenoreceptors

A

Inhibition of adenylyl cyclase → ↓ cAMP

52
Q

Action of b1 adrenoreceptors

A

Stimulation of adenylyl cyclase → ↑ cAMP

53
Q

Action of b2 adrenoreceptors

A

Stimulation of adenylyl cyclase → ↑ cAMP

54
Q

Action of nictotinic cholinoreceptors

A

Opening Na+ and K+ channels → depolarization

55
Q

Action of muscarinic cholinoreceptors

A

Stimulation of phospholipase C → ↑ IP3 → ↑ intracellular [Ca2+]

56
Q

Dual innervation by sympathetic and parasympathetic divisions

A

Most organs are dual innervated.

Usually antagonistic but often complementary

Overall function
Sympathetic: ‘fight or flight’
Parasympathetic: ‘rest or digest’

Only sympathetic innervation: sweat glands, adrenal medulla, blood vessels

57
Q

Pupil in bright light

A

Parasympathetic: constrictor/sphincter muscles contract
Increased ACh release and mAChR activity in pupillary constrictor (sphincter) muscle → sphincter muscle constricts → constricts pupil (miosis)

58
Q

Pupil in dim light

A

Symmapethetic: dilator/radial muscles contract
Increased NE release and a1 receptors activity in pupillary dilator (radial) muscle → radial muscle constricts→ dilates pupil (mydriasis)

59
Q

What is the pathophysiology of Horner’s syndrome (typical symptoms - miosis, and anhidrosis)?

A

Interruption of the sympathetic innervation of the head and neck.

60
Q

Autonomic functions of hypothalamus

A

Temperature
Food intake
Water balance

61
Q

Autonomic functions of brain stem

A
Micturition
Breathing
Cardiovascular function
Swallowing 
Coughing 
Vomiting
62
Q

Servomechanism

A

A control system uses a negative feedback mechanism to operate another system
Ex: vasomotor center in blood pressure regulation

63
Q

Temperature regulation

A

Central thermoreceptors in the anterior hypothalamus

64
Q

What is the mechanism of fever?

A

Pyrogens increase the temperature regulation set point in the hypothalamus

65
Q

Glucoreceptors

A

In the hypothalamus, regulate food intake

66
Q

Osmoreceptors

A

In the hypothalamus, regulate water intake

67
Q

Diversity as a determinant of physiologic functions

A
  1. Different transmitters, different functions
    The same effector cells (e.g., smooth muscle cells) may respond differently depending on whether it receives cholinergic or adrenergic input.
  2. Different receptors, different functions
    The same effector cells (e.g., smooth muscle cells) may respond differently when receiving adrenergic input depending on the types of adrenergic receptor.
68
Q

Specificity as a determinant of physiologic functions

A

Same transmitter/receptor, but different functions
Tissue-specific and cell type-specific
- b1 activation in the sinoatrial (SA) node: increase heart rate
- b1 activation in the atrioventricular (AV) node: increase conduction velocity
- b1 activation in the ventricular muscle: increase contractility
- b1 activation salivary gland: increase secretion
- b1 activation kidney: secrete renin

69
Q

Table of effects of ANS and organ function

A

Go look at it and study it HAHAHHA