Nervous System

Question 1

What are the actions of the sympathetic nervous system?

Answer 1

Raises heart rate 
Increases force of contraction 
Constricts most blood vessels 
Slows GI transit 
Constricts sphincters 
Bronchodilates 
Increase sweating 
Dilates pupil (mydriasis) 
Secretion of seminal fluid/movement of sperm

Question 2

What are the actions of the parasympathetic nervous system?

Answer 2

Slows heart rate (no effect on force)
Relaxes blood vessels 
Speeds up GI transit 
Relaxes sphincters 
Increases salivation 
Bronchoconstricts 
Constricts pupil (miosis) 
Erection

Question 3

What are dendrites?

Answer 3

Receptive projections sensitive to neurotransmitter input

Question 4

What is the soma of a neuron?

Answer 4

Metabolic centre

Question 5

What is an axon?

Answer 5

One-way rapid communication between cell body and axon terminals

Question 6

What is an axon terminal?

Answer 6

Form connections with other neurons/effector tissue via synapses

Question 7

What makes up the CNS?

Answer 7

Brain, spinal cord, retina & CNII

Question 8

What makes up the PNS?

Answer 8

Spinal & cranial nerves (all except CNII)
Autonomic nervous system
Somatic sensory and motor nerves

Question 9

What are the 3 branches of motor output?

Answer 9

Somatic motor - skeletal muscle
Brachio motor - pharyngeal arch muscle
Visceral/autonomic motor - organs and vessels

Question 10

What are the 3 branches of sensory input?

Answer 10

Somatic sensory - sensations from somatic tissue
Visceral sensory - sensations from organs and vessels
Special visceral sensory - taste

Question 11

At what levels of the spinal cord is a lateral horn seen?

Answer 11

T1-L2 and S2-4

Question 12

Where do neurons controlling lateral horn cells (or autonomic brainstem nuclei) arise?

Answer 12

Hypothalamus

Question 13

Where does the sympathetic chain extend up to and finish?

Answer 13

Near base of skull

Ends at tip of sacrum

Question 14

Which branch of the ANS would be damaged by vertebral damage at L1 level?

Answer 14

Parasympathetic

Question 15

What does the sympathetic chain communicates with spinal nerves via?

Answer 15

Rami communicans

Question 16

What is the difference between grey and white rami communicans?

Answer 16

White = preganglionic sympathetic neurons passing into chain 
Grey = postganglionic sympathetic neurons passing from chain into spinal nerve

Question 17

Give examples of nerves which emerge from the sympathetic chain

Answer 17

Thoracic and cardiac splanchnic nerves

Question 18

What is a dorsal root ganglion?

Answer 18

Cell bodies of sensory neurons

Question 19

At what levels are white rami communicans seen?

Answer 19

T1-L2

Question 20

At what vertebral levels are grey rami communicans seen?

Answer 20

All levels

Question 21

Where can brainstem or spinal cord injury proximal to T1 cord level affect supply to?

Answer 21

Sympathetic supply to head

Question 22

Describe the sympathetic supply to the face

Answer 22

Reticulospinal tract neurons originate in brainstem/hypothalamus
Descend to T1 & synapse with preganglionic neuron in lateral horn
Exit cord with T1 spinal nerve
Travel to sympathetic chain
Run up chain to cervical ganglia & synapse with postganglionic neuron
Postganglionic neurons enter head as plexus around internal carotid artery
Supply face via external carotid artery

Question 23

What are the 3 sympathetic chain ganglia in the neck?

Answer 23

Superior cervical - C1-4
Middle cervical - C5-6
Stellate - C7-T1, near lung apex

Question 24

What are sympathetic nerves in the head distributed with?

Answer 24

Cranial nerves and arteries

Question 25

Describe the distribution of the superior cervical ganglion to the face

Answer 25

Sympathetic neurons form a plexus around the internal carotid artery which join parasympathetic nerves Distributed with arterial branches Forms deep petrosal nerve which joins parasympathetic greater petrosal nerve and CN VII Run to pterygo-palatine ganglion from which they are distributed Distributed with branches of CN V

Question 26

What can be the effects of a pterygo-palatine fossa tumour?

Answer 26

Can compress pterygo-palatine ganglion causing loss of sympathetic and parasympathetic innervation to the face

Question 27

What does loss of sympathetic supply to the head lead to?

Answer 27

``` Horners syndrome Uneven pupil size / Pupil constriction (miosis) Vasodilation Ptosis - eyelid droop Lack of sweating (anhydrosis) ```

Question 28

Which cells of the adrenal medulla release adrenaline?

Answer 28

Chromaffin cells

Question 29

Describe parasympathetic outflow from the CNS

Answer 29

Parasympathetic nuclei sit in the brainstem Outflow with CN III, VII, IX & X Outflow with S2-4 spinal nerves

Question 30

Which cranial nerve do parasympathetic post ganglionic neurons hitchhike with?

Answer 30

CN V

Question 31

What can Frey syndrome be caused by?

Answer 31

Parotid surgery or injury | Parasympathetic nerves regrow to skin so innervate muscarinic receptors of sweat glands

Question 32

What are the 2 principal transmitters in the peripheral nervous system?

Answer 32

Acetylcholine | Noradrenaline

Question 33

What neurotransmitters does the sympathetic nervous system use?

Answer 33

ACh at pre ganglionic terminals | NA at post ganglionic terminals

Question 34

Which neurotransmitters does the parasympathetic nervous system use?

Answer 34

ACh at both pre and post ganglionic terminals

Question 35

Which ACh receptor types does the parasympathetic system use?

Answer 35

Nicotinic at pre ganglionic terminal | Muscarinic at post ganglionic terminal

Question 36

What are the sympathetic exceptions to the use of nicotinic ACh receptors?

Answer 36

Sweat glands & chromaffin cells in adrenal medulla - muscarinic receptors

Question 37

What effects do a1 receptor agonists induce?

Answer 37

Blood vessel constriction GI smooth muscle relaxation Sphincter contraction

Question 38

What effects do B1 agonists have?

Answer 38

Increased HR Increased speed of AV node conduction increased contraction force GI smooth muscle relaxation

Question 39

Where are muscarinic M1 receptors located?

Answer 39

Autonomic ganglia, induce EPSP

Question 40

Where are muscarinic M2 receptors located?

Answer 40

Heart | Negative chronotropic effects on sinoatrial node, & dromotropic on AV node & atria

Question 41

Where are muscarinic M3 receptors located?

Answer 41

Smooth muscle and vascular endothelial cells Cause smooth muscle contraction e.g. Pupil, GI transit Vascular smooth muscle relaxation - Ca2+ influx and NO release from endothelial cell – the NO causes decrease in Ca2+ in vascular myocytes)

Question 42

What is the typical ion concentration of Ca2+ inside and outside the cell?

Answer 42

Inside: 0.2μM Outside: 2mM

Question 43

What is the typical ion concentration of Cl- inside and outside the cell?

Answer 43

Inside: 5mM Outside: 115mM

Question 44

What are signs of Frey syndrome?

Answer 44

Gustatory sweating of face