Intro to Nervous - Sensory & Motor

Question 1

What is the name of the connective tissue layer surrounding the axon?

Answer 1

Endoneurism

Question 2

What is the Endoneurism?

Answer 2

A connective tissue layer that surrounds the axon of an individual neurone

Question 3

What is the name of the connective tissue layer surrounding a fascicle?

Answer 3

Perineurisum

Question 4

What is the Perineurium?

Answer 4

A connective tissue layer that surrounds a fascicle (a collection of neurons)

Question 5

What is the name of the connective tissue layer surrounding a fascicle?

Answer 5

Perineurium

Question 6

What is the Epineurium?

Answer 6

Surrounds the entire nerve; it’s formed by a collection of fascicles. Contains small blood vessels supplying the nerve fibres and is created by arachnoid and pia mater.

Question 7

What is a fascicle?

Answer 7

A bundle of neurons.

Question 8

What are Group A nerves?

Answer 8

The largest myelinated fibres that are somatic afferent and efferent fibres. Split into alpha, beta and delta.
Alpha are for efferent motor fibres
Beta are for touch sensation
Delta are for pain and temperature

Question 9

What are Group B nerves?

Answer 9

Myelinated autonomic and pre-ganglionic fibres

Question 10

What are Group C nerves?

Answer 10

They’re thin, unmyelinated fibres that are visceral and somatic afferent.

Question 11

In the frontal lobe what gyri does the central sulcus separate?

Answer 11

The precentral gyrus and postcentral gyrus

Question 12

What is the precentral gyrus?

Answer 12

Primary motor cortex for voluntary movement. Works by the homunculus.

Question 13

What is the postcentral gyrus?

Answer 13

Where integration is done, where info is processed and passes on to the pre-central gyrus to provide a response to the info. Sensory processing/integration.

Question 14

What is the sensory tracts for?

Answer 14

Pain, touch/pressure, temperature and 2-point discrimination that all follow specific pathways through the CNS

Question 15

Where do the somatosensory stimuli from below the neck pass along?

Answer 15

The sensory pathways of the spinal cord

Question 16

Where do the somatosensory stimuli from the head and neck travel?

Answer 16

Through the cranial nerves through the trigeminal system

Question 17

What are the two major pathways that bring sensory info to the brain?

Answer 17

Dorsal Column System & the Spinothalamic Tract

Question 18

How many neurons do the dorsal column system and spinothalamic tract have?

Answer 18

Three

Question 19

Where do the dorsal column system neurons cross?

Answer 19

At the medulla it reaches the 4 dorsal column nuclei

Question 20

Which of the 4 dorsal column nuclei do the peripheral and central sensations come in at?

Answer 20

Peripheral = outside nuclei
Central = the 2 inside/middle nuclei

Question 21

Where do the the 3rd order neurons travel up to?

Answer 21

The thalamus and then up the primary somatosensory cortex to the post-central gyrus

Question 22

What is the spinothalamic tract?

Answer 22

Part of the dorsal root ganglion

Question 23

What’s the tract of the spinothalamic tract?

Answer 23

Axons extend from the dorsal root within the spinal cord and synapse with the 2nd order neuron in their respective pathway

Question 24

Where do the axons in the spinothalamic tract decussate?

Answer 24

In the spinal cord at the level that they come in

Question 25

What does the dorsal column system deal with?

Answer 25

Touch and proprioception

Question 26

What does the spinothalamic tract deal with?

Answer 26

Pain and temperature

Question 27

Where is the postcentral gyrus?

Answer 27

In the somatosensory cortex

Question 28

What are neurons in the primary motor cortex called?

Answer 28

Betz cells

Question 29

What are Betz cells?

Answer 29

Neurons in the primary motor cortex that synapse with lower motor neurons in the spinal cord/brain stem

Question 30

Where do Betz cells travel?

Answer 30

The corticospinal tract (rest of body that’s not head or neck)
Or the Corticobulbar tract (cranial nerves from the cortex to brainstem - efferent)
They’re named after original or their targets (either spinal or brainstem).

Question 31

What does the corticobulbar tract do?

Answer 31

Tells the cranial nerves (the motor ones) what to do & don’t cross and thus are ipsilateral so the motor cortex are to the same side of the nervous system.

Question 32

What does the corticospinal tract do?

Answer 32

It’s the major neuronal pathway providing voluntary motor function starting in the pre-central gyrus. It generates all motor info that passes through the midbrain and once in the medulla split.

Question 33

What is the lateral corticospinal tract?

Answer 33

It’s part of the corticospinal tract where 80-90% cross at the spinal cord and tell the arms and legs what to do (appendicular appendages). Decussate in the medulla and thus are contralateral.

Question 34

What is the anterior corticospinal tract?

Answer 34

Part of the corticospinal tract that deals with the axial muscles (trunk). Some collateral branches of the tract project to ipsilateral ventral horn. Ipsilateral.