ICPP S9 The Autonomic Nervous System

Question 1

Where do parasympathetic nerves originate?

What can be said about their post/pre-ganglionics?

What can be said about their ganglia?

Answer 1

Originate in the lateral horn of the medullary/ brainstem and spinal cord segments S2-S4.

Long myelinated pre-ganglionics and short unmyelinated post ganglionics.

Ganglia located near/ within the innervated tissues.

Question 2

Where so sympathetic nerves originate?

What can be said about their pre/post-ganglionics?

What can be said about their ganglia?

Answer 2

Originate in the intermediolateral cell column, of the lateral horn through spinal cord segments T1-L2.

Pre ganglionics are short and myelinated and post ganglionics are long and non-myelinated.

Ganglia are either in the paravertebral ganglia or prevertebral ganglia.

Question 3

All pre-ganglionic neurones are ________.

Release ___ that acts on post-ganglionic ________.

nAChRs are ________-________.

Answer 3

cholinergic

ACh

nAChRs

Ligand gated

Question 4

What can be said about the NT at post-ganglionics of the PSNS?

What type of receptor is activated?

Answer 4

Cholinergic

mAChRs.

Question 5

What can be said about the NT’s pf the post-ganglionics of the SNS?

What type of receptor do they interact with?

Answer 5

Mainly nor-adrenergic

Alpha and beta adrenoceptors.

Question 6

What are some exceptions to the sympathetic post-ganglionics NTs, where are these exceptions made?

What do they activate?

Answer 6

Post-ganglionics innervate gets sweat glands and hair follicles (piloerection) are cholinergic - activate mAChRs?

Post-ganglionics that innervate that terminate in the kidney release dopamine on D1 receptors.

In the adrenal medulla the post-ganglionics are chromaffin cells.

Question 7

What some NANCs?

Answer 7

ATP - purinoceptors - purinergics.
5-HT - serotonin
NO - blood pressure regulation
Neuropeptides - vasoactive intestinal peptide, substance P.

Question 8

What does activation of M1 mAChRs lead to?

Answer 8

Secretion from salivary glands

Secretion from stomach

Question 9

What does activation of M2 muscarinic s lead to?

Answer 9

SA node - bradycardia

Reduced atrial contractile force

AV node - reduced conduction velocity of AV node.

Question 10

What does activation of M3 mAChRs lead to?

Answer 10

Smooth muscle contraction

Bronchoconstriction

Increased endocrine and exocrine secretions from salivary glands and stomach

Eye accommodation
- ciliary contraction and iris sphincter contraction.

Question 11

What does NO generation lead to?

Answer 11

Vasodilation

Penile erection via vasodilation

Question 12

What does B1 activation cause?

Answer 12

Ventricles - +ve inotropy

SA node - +ve chronotropy

AV node - +ve dromotropy - increased cardiac conduction velocity

Increased amylase secretion

Question 13

What does B2 activation cause?

Answer 13

Smooth muscle relaxation - bronchodilation.

Question 14

What does B3 activation cause?

Answer 14

Lipolysis

Relaxation of detrusor muscle in the bladder.

Question 15

What does alpha 1 activation cause?

Answer 15

Smooth muscle contraction

Vasoconstriction in skin, mucosa and abdominal viscera.

Sphincter contraction of the GI tract and urinary bladder.

Question 16

What does alpha 2 activation cause?

Answer 16

Relaxation and contraction of smooth muscle

Norepinephrine inhibition

Platelet activation.

Question 17

What doe sensory neurones monitor?

Answer 17

CO2 levels
O2 levels
Nutrients levels 
Arterial levels 
GI tract content and chemical composition

Question 18

What do the chemoreceptors in the carotid body sense?

Via what nerve is this information relayed to the CNS?

Answer 18

CO2, O2 and pH.

Glossopharyngeal nerve

Question 19

What is the nucleus tractus solitarius?

What is its role?

Where is it found?

Where else does it receive input from, what does this region sense and cause?

Answer 19

Where primary sensory neurones project to secondary sensory neurones.

Integrates all visceral afferent information.

Medulla oblongata

Area postema - detects toxins in the CSF and blood.
Essential for chemically induced vomiting and conditional taste aversion.

Question 20

What is dysautonomia?

What 2 broad ways may dysautonomia occur?

Answer 20

Umbrella term for malfunctions of the ANS

Primary disorder or as a result of secondary condition for example Parkinson’s and diabetes.

Question 21

Name 3 example of dysautonomia - briefly describe them.

Answer 21

Neruocardiogenic syncope

• Syncope is a loss of consciousness due to fall in blood pressure
• Loss of consciousness asa result of certain triggers ie sight of blood and emotional distress.

Multiple system atrophy

• degenerative neurological disorder caused by degeneration of neurones in the brain - fatal
• affects involuntary functions - blood pressure, breathing, bladder function and muscle control

POTS
- Lying to standing causes large heart rate increase