Anatomy SC: 1 and 3 Neurons, Sympathetic and PSympathetic

Question 1

Do the action potentials that pass through a dendrite travel towards or away from the cell body?

Answer 1

Towards

Question 2

Are dendrites or axons longer?

Answer 2

Axons

Question 3

What produces the myelin sheath in the PNS?

Answer 3

Schwann cells

Question 4

What produces the myelin sheath in the CNS?

Answer 4

Oligodendrocytes

Question 5

What are Schwann cells responsible for in the PNS?

Answer 5

Producing myelin sheaths

Question 6

What are Oligodendrocytes responsible for in the CNS?

Answer 6

Producing myelin sheaths

Question 7

What is the main function of the myelin sheath?

Answer 7

To greatly increase the speed of action potential along axon

Question 8

What is a collection of nerve cell bodies called in the PNS?

Answer 8

Ganglion

Question 9

What is a collection of nerve cell bodies called in the CNS?

Answer 9

Nucleus

Question 10

All motor neurons of skeletal muscles and the ANS are (multi/uni)polar

Answer 10

Multipolar

Question 11

What are unipolar neurons generally used for?

Answer 11

Sensory innervation

Question 12

Define a nerve

Answer 12

A collection of axons surrounded by connective tissue and blood vessels

(Called a nerve in the PNS but a tract in the CNS)

Question 13

Do tracts tend to be single or mixed modailty?

Answer 13

Single

Question 14

Which division is said to be responsible for the ‘fight or flight’ response?

Answer 14

Sympathetic

Question 15

Which division is said to be responsible for the ‘rest and digest’ response?

Answer 15

Parasympathetic

Question 16

What is the sympathetic division also known as?

Answer 16

Thoracolumbar outflow

Question 17

Presynaptic sympathetic cell bodies are only found between __ and __

Answer 17

T1 to L2

Question 18

Lateral horns are only found from ___ to ___

Answer 18

T1 to L2

Question 19

To join the sympathetic trunk, an action potential will exit the __ via the __ root into the __ nerve then into the __ rami then almost immediately leaves via the __ ramus (communicantes) to join the sympathetic trunk

Answer 19

To join the sympathetic trunk, an action potential will exit the SPINAL CORD via the ANTERIOR root into the SPINAL nerve then into the ANTERIOR rami then almost immediately leaves via the WHITE ramus (communicantes) to join the sympathetic trunk

Question 20

Once an action potential has reached the sympathetic trunk (ST), it will do one of 4 things…

Answer 20

Ascend, then synapse
Synapse at level of entry
Descend, then synapse
Pass through ST without synapsing to enter at abdominopelvic splanchnic nerve

Question 21

Neurotransmitter of PREganglionic sympathetic neurones is __

Answer 21

ACh

Question 22

Neurotransmitter of POSTganglionic sympathetic cells is generally __ , or __ in sweat glands

Answer 22

Generally noradrenaline

ACh in sweat glands

Question 23

Sympathetic innervation of the heart:
PREsynaptic axons synapse in __ or ___
POSTsynaptic axons pass in __ nerves to the __

Answer 23

PRE: T1 or cervical paravertebral ganglia
POST: cardiopulmonary splanchnic nerves to the SA and AV nodes and myocardium

Question 24

Sympathetic innervation of the lungs:
PREsynaptic axons synapse in the __
POSTsynaptic axons pass in __ nerves to the __

Answer 24

PRE: upper thoracic paravertebral ganglia
POST: cardiopulmonary splanchnic nerves to the bronchiolar smooth muscle and mucous glands

Question 25

Sympathetic innervation abdominopelvic organs:

PREsyanptic axons synapse in __ where they form __

Answer 25

Synapse in one of the many prevertebral ganglia where they form a plexus of nerves around arteries to travel to the target organ

Question 26

Sympathetic innervation of adrenal medulla:

PREsynaptic axons pass through the __ to synapse __

Answer 26

…pass through the aorticorenal ganglion to synapse directly onto the adrenaline/noradrenaline secretory cells (the suprarenal medullary cells)

The adrenal medulla is an exception in that it is directly innervated by preganglionic sympathetic neurones

Question 27

The parasympathetic innervation is also known as

Answer 27

The craniosacral outflow

Question 28

Where are preganglionic parasympathetic neurones located?

Answer 28

In the brainstem and spinal cord

Question 29

Presynaptic parasympathetic axons leave the CNS via

Answer 29

CN III, VII, IX and X
Sacral spinal nerves
Craniosacral outflow

Question 30

How do the parasympathetic axons travel to the eye?

Answer 30

Cilliary ganglion

Question 31

How do the parasympathetic axons travel to the hindgut, pelvis and perineum?

Answer 31

Sacral spinal nerves

Question 32

What do the parasympathetic ganglia in the head supply?

Answer 32

Lacrimal and salivary glands

Question 33

What does the vagus nerve supply?

Answer 33

Organs of neck, chest and abdomen as far as hindgut

Vagus nerve synapses in or at wall of target organ

Question 34

In the sympathetic division, preganglionic neurones have __ (long/short) axons while post ganglionic fibres are relatively __ (long/short)

Answer 34

In the sympathetic division, preganglionic neurones have SHORT axons while post ganglionic fibres are relatively LONG.

This is due to the sympathetic chain that runs alongside the vertebral column made up of sympathetic ganglia

Question 35

In the parasympathetic division, ganglia are located __

Answer 35

Close to the target organ

This means preganglionic neurones have long axons and postganglionic fibres are short