ANATOMY - SPINAL NERVES and HISTOLOGY OF NERVE

Question 1

In the spinal cords, what is the ventral horn , what does it look like?

Answer 1

The horn facing the front of the Body. It is the rounder of the 2 horns

Question 2

What is contained in grey matter? Where in the spinal cord is it?

Answer 2

It is in the centre, the part that looks like a H.
It contains nerve cells

Question 3

What is contained in the white matter of spinal cords

Answer 3

axons, many myelinated

Question 4

Where is the spinal cords located?

Answer 4

In the vertebral canal

Question 5

Where is the central canal located?

Answer 5

In the grey matter of the spinal cords

Question 6

Do sensory neurons enter the spinal cord through the ventral or dorsal horn?

Answer 6

The dorsal

Question 7

Do motor neurons exit the spinal cord through the ventral or dorsal horn?

Answer 7

Ventral

Question 8

Are spinal nerves paired?

Answer 8

Yes

Question 9

How many pairs of spinal nerves are there? List them

Answer 9

31 pairs.
C1-C8
T1-T12
L1-L5
S1-S5
1 Co (coccyx)

Question 10

How is the spinal nerve formed from the spinal cords?

Answer 10

The posterior root and anterior root which originate from the spinal cords fuse to form the spinal nerve.

Question 11

Do the spinal nerves divide?

Answer 11

Yes.
Into anterior and posterior rami.

Question 12

What is a dermatome?

Answer 12

A strip of skin supplied by a single spinal nerve

Question 13

What is a myotome?

Answer 13

All the skeletal muscle innervated by a single spinal nerve.

Question 14

What must you test for when testing nerve function?

Answer 14

Motor and sensory loss

Question 15

What are lower motor neurons?

Answer 15

Motor neurons which exit through the ventral horn of grey matter and innervate skeletal muscle

Question 16

What is contained in the dorsal root ganglion?

Answer 16

The cell bodies of many sensory neurons

Question 17

What is one structural difference between motor and sensory neurons?

Answer 17

Motor neurons are multipolar

Sensory neurons are unipolar

Question 18

Where can sensory nerve endings be found?

Answer 18

Skin
Joint capsules
Muscles

Question 19

Draw a motor neuron

Question 20

Draw a sensory Neuron

Question 21

Draw an Interneuron

Question 22

What makes up the CNS?

Answer 22

Brain and spinal cord

Question 23

What makes up the PNS?

Answer 23

Cranial nerves and spinal nerves

Question 24

What are the 2 cell types in nervouse tissue?

Answer 24

Neurons
Neuroglia/support cells

Question 25

What do interneurons do?

Answer 25

Send signal through CNS pathways

Question 26

What are bundles of neuron processes called in the CNS?

Answer 26

Tracts

Question 27

What are bundles of neuron processes called in the PNS?

Answer 27

Nerves

Question 28

What is the cytoplasm called int he neuron cell body?

Answer 28

Perikaryon

Question 29

Neuron cell bodies have few mitochondria t/f?

Answer 29

False. They have many

Question 30

What are Nissl bodies and where are they found?

Answer 30

Clusters of RER Found in base of dendrites and axon hillock

Question 31

What are neurofilaments

Answer 31

Bundles of intermediate filaments found in neuron cell bodies They give scaffolding and shape to the cell bodies

Question 32

What structures allow transport of neurotransmitters within neurons?

Answer 32

Microtubules

Question 33

What do dendrites do ?

Answer 33

Transmit impulse towards cell body

Question 34

How many axons does one neuron have?

Answer 34

1

Question 35

What do axons do?

Answer 35

Transmit impulses away from cell body

Question 36

What are the branches at the end of the axon called?

Answer 36

End axon terminals/ terminal boutons

Question 37

What are the 3 structural classifications of neurons?

Answer 37

- multipolar - bipolar - pseudounipolar / unipolar

Question 38

Describe structure and function of a multipolar neuron

Answer 38

Has many dendrites and one axon The most common type of neuron Innervate skeletal muscle

Question 39

Describe structure and function of bipolar neurons

Answer 39

2 processes Rare neurons Found in some sensory organs e.g retina of eye

Question 40

Describe stucture and function of unipolar/ pseudounipolar neurons

Answer 40

- 1 short process - Have a short projection which extends into 2 axons -One axon goes into CNS -One axon goes the the PNS - SENSORY NEURONS

Question 41

What is a synapse?

Answer 41

Site at which one neuron communicates with: • another neuron, or • an effector cell

Question 42

Can synapses transmit impulses in either direction?

Answer 42

No. One direction only

Question 43

What are the different types of synapses (STRUCTURALLY)

Answer 43

- axodendritic - axosomatic (axon -> cell body) - axoaxonic - others which are uncommon

Question 44

What are the types of synapse (method of transmitting signal)

Answer 44

- electrical synapse - chemical synapse ( more common)

Question 45

What are the components of a chemical synapse?

Answer 45

1. Presynaptic terminal bouton 2. Synaptic cleft 3. Postsynaptic membrane

Question 46

What are the support cells on the CNS?

Answer 46

- astrocytes - microglia - oligodendrocytes - Ependymal cells

Question 47

What are the support cells in the PNS?

Answer 47

- Schwann cells - Epineurium - Perineurium - Endoneurium

Question 48

What is the function of astrocytes?

Answer 48

- scaffolding - blood brain barrier (foot processes line the meninges forming an impermeable barrier)

Question 49

What is the function of oligodendrocytes ?

Answer 49

- form myelin sheath around many axons in CNS

Question 50

Function of microglia?

Answer 50

- small phagocytes ( macrophages of CNS ) - migrate towards injured neurons - engulf invading organisms and dead neurons

Question 51

Function of Ependymal cells?

Answer 51

- line cerebrospinal fluid filled cavities - have cilia to help circulation of CSF

Question 52

What is the Epineurium ?

Answer 52

Surrounds entire nerve

Question 53

What is the Perineurium ?

Answer 53

Surrounds each nerve fascicle

Question 54

What is the Endoneurium ?

Answer 54

Surrounds each individual nerve fibre/axon Extends from spinal cord almost to nerve ending

Question 55

Symptoms of multiple sclerosis?

Answer 55

- visual disturbances - muscle weakness - sensory loss

Question 56

What is the cause of Multiple sclerosis?

Answer 56

The immune system attack myelin around axons in the CNS - impulse conduction if slowed and eventually ceases