Ch 2 - ANS Flashcards

(53 cards)

1
Q

Two Divisions of the Nervous System

A

Central Nervous System (CNS) = Brain and the spinal cord

Peripheral Nervous System (PNS) = Everything outside of CNS

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2
Q

Sensory (Afferent) Nervous System

A
  • Brings information INTO the NS
  • Begins with events in sensory receptors in the periphery
  • Simplistic Pathway: Receptors -> Brainstem -> Diecephalon -> Cortex
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3
Q

Motor (Efferent) Nervous System

A
  • Carries information from the NS TO the periphery
  • 2 components = Somatic (Voluntary) & Autonomic (Involuntary)
  • Efferent information results in contraction of muscle or secretion by glands
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4
Q

2 Components of the CNS

A

Somatic: Voluntary, largely involves skeletal muscles

Autonomic (ANS): Involuntary, largely smooth muscle & glands

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5
Q

Somatic Nervous System

A
  • Voluntary; Conscious control
  • SINGLE MOTORNEURON and the skeletal muscle innervated: Each muscle fiber is innervated by a single motor neuron
  • Cell body of the motor neuron is located in the CNS
  • Neurotransmitter: Acetylcholine (ACh)
  • Receptor: Nicotinic
  • Action potential in motor neuron -> EPP in muscle fiber -> depolarization of muscle -> contraction
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6
Q

Neurotransmitter of Somatic Nervous System

A

Acetylcholine (ACh)

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7
Q

Neurotransmitter Receptor of Somatic Nervous System

A

Nicotinic

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8
Q

3 Divisions of the ANS

A
  • Sympathetic
  • Parasympathetic
  • Enteric = is the intrinsic innervation of the GI tract
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9
Q

The neurotransmitter of every Preganglionic Neuron is

A

Acetylcholine (ACh)

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10
Q

The receptor of every Preganglionic Neuron is

A

Nicotinic

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11
Q

Origin of the Sympathetic Division ANS

A

T1-L3 (Thoracocolumbar/Adrenergic Division)

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12
Q

Origin of the Parasympathetic Division ANS

A

CN 3, 7, 9, 10, & S2-S4 (Craniosacral)

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13
Q

Overall function of the Sympathetic Division

A

Mobilize the body for activity

Responds to stressful situations

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14
Q

Location & Projection of Preganglionic Neurons in the Sympathetic Division

A

Location: Intermediolateral cell column (T1-L3)
Projection:
• Via ventral roots and white communicating rami to the sympathetic trunk or paravertebral ganglia
• Via splanchnic nerves to prevertebral (collateral) ganglia
- They synapse at both locations w/ postganglionic neurons

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15
Q

Location & Projection of Postganglionic Neurons in the Sympathetic Division

A

Location:
• Sympathetic trunk (paravertebral ganglia)
• Prevertebral (collateral) ganglia
Projection:
• In sympathetic trunk: Via gray communicating rami to spinal nerves
• In prevertebral ganglia: project to abdominal & pelvic viscera

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16
Q

Interneurons in the Sympathetic Division are called

A

Small Intensely Fluorescent (SIF) cells

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17
Q

Interneurons in the Sympathetic Division are located in

A

Sympathetic ganglia

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18
Q

The neurotransmitters of Sympathetic Division Interneurons are

A

Dopamine; they are inhibitory

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19
Q

Norepinephrine is the NT of these neurons

A

Postganglionic Sympathetic Neurons. Exception are sweat glands & some blood vessels which have cholinergic innervation

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20
Q

Dopamine is the NT of these cells

A

SIF cells

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21
Q

Neuro-Effector Junctions in sympathetic division are analogous to neuromuscular junctions of the somatic NS, however there are these differences

A
  1. NMJ has a discrete arrangement where there is a single motor neuron innervating muscle. In contrast, in the ANS, postganglionic neuron is diffuse w/ a branching pattern w/ beads, or varicosities, line branches.
  2. There is overlap in the branching networks from different postganglionic neurons, s/t target tissues may be innervated by many postganglionic neurons
  3. In the ANS, postsynaptic receptors are widely distributed on the target tissues, and there is no specialized region of receptors analogous to the motor end plate of skeletal muscle
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22
Q

The Adrenal Medulla

A
  • Innervation originates from T5-T9
  • No postganglionic neuron
  • Specialized ganglion in the sympathetic division of the ANS
  • Secretes 80% epinephrine & 20% norepinephrine
  • ACh is NT of Preganglionic & Nicotinic is receptor
23
Q

Pheochromocytoma

A
  • Tumor of the adrenal medulla

- Secretes mainly norepinephrine

24
Q

Location of Alpha1 Adrenergic Receptors

A
  • Vascular smooth muscle of the skin
  • Splanchnic regions (organs)
  • GI system
  • Bladder
  • Radial muscle of the eye (mydriasis - when your pupils dilate)
25
Action of Alpha1 Adrenergic Receptors
Produce excitation; contraction/constriction
26
Location of Alpha2 Adrenergic Receptors
Platelets | Walls of GI tract
27
Action of Alpha2 Adrenergic Receptors
Produce inhibition, eg: Relaxation/dilation
28
Location of Beta1 Adrenergic Receptors
Sinoatrial (SA) & Atrioventricular (AV) node Cardiac muscle Fat cells (increase lipolysis) Kidney (renin secretion)
29
Action of Beta1 Adrenergic Receptors
Excitation; increased HR, increased conduction, increased contractility
30
Location of Beta2 Adrenergic Receptors
Vascular smooth muscle of skeletal muscle (relaxation) Bronchial smooth muscle (dilation) Walls of GI tract & bladder
31
The parasympathetic division is aka
Craniosacral or Cholinergic System
32
The overall function of the Parasympathetic division is
Restoration & conservation of energy
33
The NT for the parasympathetic division
ACh as NT for both pre & post ganglionic synapses
34
Location of Nicotinic Cholinergic Receptors
- Autonomic ganglia of symp & parasymp system - Neuromuscular junction - Adrenal medulla
35
Location of Muscarinic Cholinergic Receptors
M1: salivary glands, stomach M2: heart M3: endocrine & exocrine glands, ciliary muscles, vascular smooth muscle
36
Action of Muscarinic Cholinergic Receptors
Inhibitory in heart (lower Heart Rate, lower conduction velocity in AV node) Excitatory in smooth muscle & glands (higher GI motility, higher secretion
37
Length of preganglionic axons are short in the
Sympathetic Division
38
Length of preganglionic axons are long in the
Parasympathetic Division
39
Length of postganglionic axons are short in the
Parasympathetic Division
40
Length of postganglionic axons are long in the
Sympathetic Division
41
Location of autonomic ganglia in Sympathetic Division vs Parasympathetic Division
Sympathetic Division: Paravertebral & Prevertebral Parasympathetic Division: In or near effector organs
42
Neurotransmitter in effector organs of Sympathetic Division vs Parasympathetic Division
Sympathetic: Norepinephrine (except sweat gland) Parasympathetic: ACh
43
MOA of Alpha 1 Adrenergic Receptor
Formation of IP3 & Increase in Ca2+
44
MOA of Alpha 2 Adrenergic Receptor
Inhibit adenylate cyclase & decrease in cAMP
45
MOA of Beta 1 Adrenergic Receptor
Activation of adenylate cyclase & production of cAMP
46
MOA of Beta 2 Adrenergic Receptor
Activation of adenylate cyclase and production of cAMP
47
Formation of IP3 & Increase in Ca2+ is the MOA of which Adrenergic Receptor?
Alpha 1
48
Inhibition of adenylate cyclase & decrease in cAMP are the MOA of which Adrenergic Receptor?
Alpha 2
49
Activation of adenylate cyclase & production of cAMP are MOA of which Adrenergic Receptor?
Beta 1 & 2
50
Parasympathetic Cholinergic Varicosities; the small clear vesicles release
Small, clear vesicles: release the classic NT ACh
51
Parasympathetic Cholinergic Varicosities; the large dense-core vesicles
Non-classic neurotransmitters: • Vasoactive intestinal peptide [VIP] • Nitric oxide [NO] -> Varicosities contain nitric oxide synthase and can synthesize NO on demand
52
MOA of Muscarinic receptor in SA node
Inhibition of adenylate cyclase, (α₂) which leads to the opening of K⁺ channels, causing repolarization, thereby ↓ing HR
53
MOA of Muscarinic receptor in smooth muscle & glands
Formation of IP₃ and increase intracellular Ca²⁺; (α₁)