Session 1 Topography

Question 1

What is grey matter composed of?

Answer 1

Cell bodies and dendrites

BUT it does also have axons which allow it to communicate with white matter

Question 2

What is white matter composed of?

Answer 2

Axons (with their supporting cells)

Question 3

Why is white matter white?

Answer 3

Due to the presence of fatty myelin

Question 4

What is the PNS equivalent of grey matter?

Answer 4

A ganglion

Question 5

What is the PNS equivalent of white matter?

Answer 5

A Peripheral nerve

Question 6

Why is grey matter grey?

Answer 6

It’s highly vascular (reflects its computational role)

Question 7

Define Funiculus (plural = funiculi)

Also - what direction do the impulses travel in?

Answer 7

A segment of WHITE matter containing lots of distinct tracts

Impulses travel in multiple directions

Question 8

Define tract

what direction do the impulses travel in?

Answer 8

An anatomically and functionally defined white matter pathway connecting two distinct regions of grey matter

Impulses travel in ONE direction

‘One direction have a good trac(t)’

Question 9

Define Fasciculus (plural = fasciculi)

Answer 9

A subdivision of a tract supplying a distinct region of the body

Question 10

Define nucleus (grey matter)

Answer 10

A collection of functionally related cell bodies

Question 11

Define cortex (grey matter)

How thick is it?

Answer 11

A folded sheet of cell bodies found on the surface of the brain structure

1-5mm thick

Question 12

Define fibre (white matter)

Answer 12

• a term relating to an axon in association with its supporting cells (e.g. oligodendrocytes)

(Used synonymously with ‘axon’)

Question 13

What do association fibres connect?

Answer 13

Cortical regions within the SAME hemisphere

Question 14

What do commissural fibres connect?

Answer 14

Left and right hemispheres (or cord halves)

Question 15

What do projection fibres connect?

Answer 15

The cerebral hemispheres with the cord/brainstem (and vice versa)

Question 16

Midbrain

• function (2)
• a.k.a.?

Answer 16

1. eye movements
2. reflex responses to sound and vision

A.k.a. Mesencephalon

Question 17

Pons

Function? (2)

Answer 17

Feeding

Sleeping

Question 18

Medulla

Answer 18

Cardiovascular and respiratory centres

Contains a major motor pathway (medullary pyramids)

Question 19

Central sulcus

What plane does it sit in and what does it separate?

Answer 19

Coronal plane

Separates frontal and parietal planes

Question 20

What does the precentral gyrus contain?

Answer 20

Primary motor cortex

Question 21

What does the postcentral gyrus contain?

Answer 21

Primary sensory cortex

Question 22

What does the lateral (Sylvian) fissure separate?

Answer 22

Temporal from frontal/parietal lobes

Question 23

What does the parieto-occipital sulcus separate?

Answer 23

Parietal from occipital lobe

Question 24

Relevance of the calcarine sulcus?

Answer 24

The primary visual cortex surrounds it

Question 25

Relevance of the optic chiasm?

Answer 25

A site where fibres in the visual system cross over

Question 26

Relevance of the uncus? what lobe is it part of? What important role does it have?

Answer 26

Part of the temporal lobe that can herniate and compress the midbrain Important olfactory role

Question 27

Parahippocampal gyrus?

Answer 27

Key cortical region for memory encoding (inferio-medial aspect of brain)

Question 28

What is the corpus callosum?

Answer 28

Fibres connective the two cerebral hemispheres (v dense!)

Question 29

Function of the thalamus?

Answer 29

Sensory relay station projecting to sensory cortex

Question 30

Importance of cingulate gyrus?

Answer 30

Cortical area important for emotion and memory

Question 31

Hypothalamus function

Answer 31

Essential centre for homeostasis

Question 32

What is the fornix?

Answer 32

Major output pathway for the hippocampus

Question 33

what is the tectum?

Answer 33

Dorsal part of the midbrain involved in involuntary responses to auditory and visual stimuli

Question 34

relevance of cerebellar tonsils?

Answer 34

Part of the cerebellum that can herniate and compress the medulla

Question 35

What makes CSF?

Answer 35

Choroid plexus in the ventricles

Question 36

How much CSF is made a day?

Answer 36

600-700 ml in total

Question 37

Where is CSF reabsorbed?

Answer 37

Arachnoid granulations (and some other sites)

Question 38

If there was a blockage in the aqueduct, what would happen to the ventricles?

Answer 38

The lateral ventricles would dilate (their CSF drainage is blocked) The 3rd ventricle would dilate The 4th ventricle would be normal as the blockage is further upstream so the CSF can drain through the 4th ventricles aperture’s normally

Question 39

How do you treat an aqueductal stenosis?

Answer 39

Ventriculoperitoneal shunt = shunt has a valve with one-way flow = the end with the catheter is placed in the 3rd ventricle and the other end is placed in the peritoneal cavity - excess CSF is reabsorbed by the surrounding tissue

Question 40

Consequence’s of aqueductal stenosis?

Answer 40

Can lead to hydrocephalus * headaches and raised intracranial pressure * difficulty looking up