Physiology of the Autonomic Nervous System

Question 1

Where do Parasympathetics exit CNS, Location of ganglia, Length of pre-ganglionic axon, length of post ganglionic axon

Answer 1

• Cranial and Sacral
• On or near the target organ
• pre ganglionic is long and must travel to the ganglion on the target organ
• post ganglionic is short

Question 2

Where do sympathetics exit CNS, Location of ganglia, Length of pre-ganglionic axon, length of post ganglionic axon

Answer 2

• Thoracic Lumbar
• Sympathetic chain,
• Pre-ganglionic fibers are short and must travel to sympathetic chain just outside the spine
• Post ganglionic fibers are long

Question 3

In an Autonomic reflex arc, where is the information being processed

Answer 3

• Instead of being processed in the spinal cord for a normal skeletal muscle reflex arc
• It is processed in the hypothalamus of the brain

Question 4

At the first synapses between pre and post ganglion in the autonomic reflex arc, what neurotransmistter is released between the two, and what receptors up take this? in both parasympathetic and sympathetics

Answer 4

It is the same for both the parasympathetic and sympathetic

Acetylcholine

Nicotinic cholinergic receptors

Question 5

At the second synapses between the post ganglionic axon and target organ in the autonomic reflex arc, what neurotransmistter is released between the two, and what receptors up take this? in both parasympathetic and sympathetics

Answer 5

in the Parasympathetic Branch:
Acetylcholine
Muscarinic Cholinergic receptors on the target organs

In the Sympathetic Branch:
Norepinephrine (Noradrenaline)
Adrenergic receptor

Question 6

locations, functions of: M1R

Answer 6

Muscarinic Cholinergic Receptor 1

Can be found in the CNS (not autonomic, but role in memory)

Salivary glands- Increase secretion (Autonomic)
Acid secreting cells of stomach- increase secretion (Autonomic)

Gq/11 so they use G coupled proteins to increase intracellular Ca++

Question 7

locations, functions of: M3R

Answer 7

Muscarinic Cholinergic Receptor 3

Smooth muscle cells (Contraction)
Exocrine Glands (secretion)

Both Autonomic roles

Gq/11 lead to increase of intracellular Ca++

Question 8

locations, functions of: M5R

Answer 8

Muscarinic Cholinergic Receptor 5

Found in CNS, role is uncertain

Gq lead to increase in intracellular Ca++

Question 9

locations, functions of: M2R

Answer 9

Muscarinic Cholinergic receptor 2

Cardiac and extensively at the SA node
slows heart rate

Autonomic system role

Gi/o Decreases cAMP and interacts with K channels

Question 10

locations, functions of: M4R

Answer 10

Muscarinic Cholinergic receptor 4

role uncertain

Gi/0 decreases cAMP and interacts with K channels

Question 11

What affect must M2R have on K+ channels in order to slow heart rate

Answer 11

it opens the K+ channels which causes a repolarization and hyperpolarization which makes it harder for the heart to fire

Question 12

locations, functions of: Alpha 1 adrenergic receptors

Answer 12

Gq/11 (Phospholipase pathway)

lead to increase of Ca++ intracelluarly

Located on:
Smooth muscle of blood vessels (contraction)
Smooth muscle of urinary and reproductive tracts
Liver (glycogenolysis and gluconeogenesis)
Adipose tissue (lipolysis)
Lacrimal glands (reduce watery secretion)
Radial muscle of iris (contraction leads to dilation of pupil)

Question 13

locations, functions of: Alpha 2 adrenergic receptors

Answer 13

Gi/o coupled

decrease adenylate cyclase/camp

Locate on:
GI sphinctors (contraction)
Pancreas (increase glucagon, decrease insulin)
Smooth muscle of blood vessels (dilation)
Platelets (increase clotting)

Question 14

locations, functions of: Beta 1 adrenergic receptors

Answer 14

Gs Coupled

Increased adenylate cyclase activity and cAMP production

Primary location:
Cardiac tissue SA node (increase heart rate)
Cardiac tissue ventricle muscle (increase strength of contraction)
Salivary glands (viscous secretion)
Adipose tissue (lipolysis)

Question 15

locations, functions of: Beta 2 adrenergic receptors

Answer 15

Gs coupled

Lead to increased adenylate cyclase activity and cAMP prodution

Location:
Bronchiole smooth muscle (relaxation)
Gastrointestinal smooth muscle (relaxation)
Urinary/reproductive smooth muscle (relaxation)
Vascular smooth muscle (relaxation)
Liver (glycogenolysis)
Eye (relaxation of ciliary muscle flattens lens to see distance)

Question 16

locations, functions of: Beta 3 adrenergic receptors

Answer 16

Gs coupled

lead to increased adenylate cyclase activity and cAMP production

Primary location:
White adipose tissue (lipolysis)
Brown adipose tissue (heat production)

Question 17

What is the effect of Varicosities at the 2nd synapse of the Autonomic reflex arc

Answer 17

work similar to the pre synaptic terminal except the ligand receptors are not concentrated at the pre synaptic terminal but are more spread out so that the start of the action can occur over a spread out area

Question 18

Chromaffin cells location and function

Answer 18

found at the adrenal medulla by the kidneys and they make and release epinephrine as part of the sympathetic response

Question 19

How does the release of Epinephrine into the blood work?

Answer 19

Pre ganglionic Sympathetic neurons skip the paravertebral ganglion and synapse on the adrenal medulla and release Acetyl choline which binds the Nicotinic receptors on the chromaffin cells

These then will release epinephrine into the blood

Question 20

Sympathethetic affects on the body

Answer 20

Fight or flight

Iris of eye: Dilation
Ciliary muscle of eye: relax (far vision)
Salivary glands: reduce secretion
Lacrimal gland: reduce secretion
Heart SA node: increase rate
Heart muscle: increase strength of contraction
Bloodvessels: constrict
Capillaries: Dilate
Bronchi: Dilation
GI secretion: Decrease
GI motillity: Decrease
GI Sphinctor: Increase
Sweat glands: increase
LIver: increase gluconeogenesis, glycogenolysis
Adipose tissue: increase Lipolysis

Question 21

Parasympathetics effect on body

Answer 21

Rest and digest

Iris of eye: constrict
ciliary muscle of eye: contract for near vision
Salivary glands: watery secretion
Lacrimal glands: increase
Heart SA node: decrease rate
Heart muscle: XXX
Blood vessels: XXX
Bronchi: Constriction
GI secretion: increase
GI motility: Increase
GI sphincter: Decrease
Sweat glands: XXX
Liver: XXX
Adipose tissue: XXX