lecture 22 - movement & sensation

Question 1

What are the major sulci/fissures of the brain (4)?

Answer 1

Central, lateral and parietal-occipital sulcus, transverse fissure

Question 2

What parts of the brain does the central sulcus divide?

Answer 2

Frontal and Parietal lobes

Question 3

What parts of the brain does the lateral sulcus divide?

Answer 3

Frontal and temporal lobe

Question 4

What parts of the brain does the parieto-occipital sulcus divide?

Answer 4

Parietal and occipital lobes.

Question 5

What parts of the brain does the transverse fissure divide?

Answer 5

The cerebellum from the temporal and occipital lobes.

Question 6

What are the functions of the frontal lobe?

Answer 6

Motor control (top) & language and personality (bottom)

Question 7

What are the functions of the temporal lobe?

Answer 7

Memory and hearing

Question 8

What are the functions of the parietal lobe?

Answer 8

Somatosensory

Question 9

What are the functions of the occipital lobe?

Answer 9

Vision (contains visual cortex)

Question 10

What is the diencephalon?

Answer 10

Small part within the centre of the brain, that contains the thalamus and hypothalamus.

Question 11

What is the corpus callosum?

Answer 11

A bundle of nerve fibres (myelinated axons) that connect the two hemispheres of the brain.

Question 12

What is the colour of the corpus callosum, and why is it this colour?

Answer 12

White - contains fat, in the form of myelin on the axons bound with oligodendrocytes.

Question 13

Where is the cerebellum located?

Answer 13

At the bottom/back of the brain.

Question 14

Where does the brain stem attach to the rest of the brain?

Answer 14

At the thalamus (of the diencephalon)

Question 15

What are the parts of the brain stem, from superior to inferior?

Answer 15

Midbrain, pons, medulla oblongata

Question 16

Where does the brain stem connect to the spinal cord?

Answer 16

Through the foramen magnum to the medulla oblongata

Question 17

What is the structure and appearance for the cerebral cortex?

Answer 17

Made up of cell bodies (grey matter)

Question 18

What is white matter?

Answer 18

Tracts of myelinated axons within the brain.

Question 19

What are the 3 types of white matter?

Answer 19

Commissural, projection and association tracts.

Question 20

What are commissural tracts?

Answer 20

Bundles of axons that cross from 1 hemisphere of the brain to the other.

Question 21

The corpus callosum is an example of which type of tracts?

Answer 21

Commissural tracts.

Question 22

What are projection tracts?

Answer 22

Tracts of axons that extend between the cortex and other CNS areas outside of the cerebrum. (e.g. corticospinal tract)

Question 23

What type of tract is the corticospinal tract?

Answer 23

A projection tract

Question 24

What does. the corticospinal tract connect?

Answer 24

The cerebral cortex to the spinal cord.

Question 25

What are association tracts?

Answer 25

Tracts of axons that connect parts of the cerebral cortex in the same hemisphere. Allows for short or long distance communication.

Question 26

What part of the brain functions as the primary motor cortex?

Answer 26

Pre-central gyrus.

Question 27

What is the location of the pre-central gyrus?

Answer 27

Adjacent to the central sulcus, in the frontal lobe.

Question 28

What is the pre-central gyrus made up of?

Answer 28

Cell bodies of upper motor neurons that form somatic efferent pathways.

Question 29

How does the primary motor cortex control movement?

Answer 29

Specific regions of the motor cortex control specific regions of the body, with more neurons for more delicately controlled body parts.

Question 30

What is the overall pathway for information in somatic efferent motor control?

Answer 30

Upper to lower motor neuron, then to effector (skeletal muscle).

Question 31

Where is the cell body on an upper motor neuron of the somatic efferent pathway found?

Answer 31

In the primary motor cortex/pre central gyrus.

Question 32

What is the pathway of the axon of the upper motor neuron in a somatic efferent pathway?

Answer 32

Extends from motor cortex to spinal cord, crossing over (usually at the medulla oblongata) to the opposite side of the cord before synapsing with the lower motor neuron.

Question 33

Where is the cell body of a lower motor neuron in a somatic efferent pathway?

Answer 33

Ventral horn (grey matter) of spinal cord, on opposite side to the original motor neuron’s origin in the primary motor cortex.

Question 34

What is the pathway of the axon of the lower motor neuron in the somatic efferent pathway?

Answer 34

Extends out of ventral root of the spinal cord into the body where it makes a synapse on skeletal muscle.

Question 35

What structure of the brain is associated with somatosensory perception?

Answer 35

Post-central gyrus

Question 36

What is somatosensory perception?

Answer 36

Conscious perception of touch, pressure, temperature, etc.

Question 37

What is the location of the post-central gyrus?

Answer 37

On the parietal lobe, adjacent to the central sulcus.

Question 38

Where is the primary somatosensory cortex?

Answer 38

At the post-central gyrus

Question 39

How many neurons are in the dorsal column pathway?

Answer 39

3

Question 40

What does the dorsal column pathway control?

Answer 40

Somatosensory perception

Question 41

Where is the first neuron in the dorsal column pathway?

Answer 41

Input zone at sensory receptors, cell body in dorsal root ganglion, output zone ascends the brain stem (dorsal column) to make synapse with neuron 2 in medulla oblongata.

Question 42

What class of neuron (—polar) is the 1st neuron in the dorsal column pathway?

Answer 42

Unipolar

Question 43

What are the locations of the 2nd neuron in dorsal column pathway?

Answer 43

Cell body in medulla oblongata, axon crosses to opposite side of spinal cord and makes synapse to neuron 3 at thalamus

Question 44

What are the locations of the components of Neuron 3 in the dorsal column pathway?

Answer 44

Cell body in thalamus, axon ascends to somatosensory cortex, makes synapse to cell body of somatosensory neuron for touch to be perceived.

Question 45

What is a motor unit?

Answer 45

A unit consisting of a motor neuron and all the muscle fibres it innervates.

Question 46

How many muscle fibres can a single motor neuron synapse with?

Answer 46

Up to a few thousand

Question 47

What is the structure of a small motor unit?

Answer 47

Consists of one motor neuron and a few dozen muscle fibres

Question 48

what is the structure of a large motor unit?

Answer 48

Single motor neuron and as many as a few thousand muscle fibres

Question 49

What does the corticospinal/pyramidal tract control?

Answer 49

The control of precise,voluntary movements