Session 1: Unit Introduction and Basic Topography

Question 1

Composition of grey matter

Answer 1

Cell bodies and dendrites

It is highly vascular which reflects its computational role.

Question 2

Composition of white matter

Answer 2

Axons and their supporting cells.

Question 3

Why is grey matter; grey, and white matter; white?

Answer 3

White matter is white because of its high concentration of axons with myelin (fat) making it white.

Grey matter does also have axons in order to communicate with white matter but not at all in the same concentration as white matter.

Question 4

What is the PNS equivalent of grey matter?

Answer 4

Ganglion (collection of cell bodies)

The basal ganglia is an exception.

Question 5

What is the PNS equivalent of white matter?

Answer 5

Peripheral nerve

Question 6

Explain where white matter and grey matter can be found in the spinal cord.

Answer 6

Grey matter is at its core and whiter matter is found as an outer shell.

Question 7

Define funiculus.

Answer 7

A segment of white matter containing multiple distinct tracts.

The impulses travel in multiple directions.

Question 8

Define tract.

Answer 8

An anatomically and functionally defined white matter pathway where two distinct regions of grey matter are connected by.

The impulses travel in one direction.

An example is the corticospinal tract.

Question 9

Define fasciculus.

Answer 9

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

Question 10

White matter is organised into tracts.

What is grey matter organised into?

Answer 10

Cell columns

Question 11

What is a nucleus?

Answer 11

It is a collection of functionally related cell bodies.

Question 12

What is cortex?

Answer 12

A folded sheet of cell bodies found on the surface of a brain structure. This is grey matter.

It should be around 1-5 mm thick.

Question 13

What is fibre?

Answer 13

White matter.

This term relates to the axon and its associated supporting cells (oligodendrocytes in CNS and Schwann cells in the PNS)

Question 14

Explain association fibres.

Answer 14

Connect cortical regions within the same hemisphere

Question 15

Explain commissural fibres.

Answer 15

Connect left and right hemispheres or cord halves.

Question 16

Explain projection fibres.

Answer 16

Connect cerebral hemispheres with the cord/brainstem and vice versa

Question 17

Answer 17

Question 18

Functions of the midbrain.

Answer 18

Eye movements and reflex responses to sound and vision.

Question 19

Functions of pons

Answer 19

Feeding and sleep

Question 20

Functions of medulla

Answer 20

Cardiovascular and respiratory centres.

Contains a major pathway (medullary pyramids)

Question 21

Answer 21

Question 22

Function of lateral/sylvian fissure.

Answer 22

Separates temporal from frontal/parietal lobes

Question 23

Function of parieto-occipital sulcus

Answer 23

Separates parietal from occipital lobe.

Question 24

What is the calcarine sulcus surrounded by?

Answer 24

Primary visual cortex.

Question 25

Answer 25

Question 26

Why is the uncus important?

Answer 26

It is a part of the temporal lobe that can herniate and compress the midbrain.

It also has an important olfactory role.

Question 27

Function of parahippocampal gyrus

Answer 27

Key cortical region for memory encoding.

Provides input to the underlying hippocampus.

Question 28

Answer 28

Question 29

Answer 29

Question 30

What is the corpus callosum?

Answer 30

A central structure in the brain which consists of fibres that connect the two cerebral hemispheres.

Question 31

What is the thalamus?

Answer 31

A sensory relay station projecting to sensory cortex.

Question 32

What is the cingulate gyrus?

Answer 32

A cortical area important for emotion and memory

Question 33

What is the hypothalamus?

Answer 33

Region under thalamus that is an essential centre for homeostasis.

Question 34

What is the fornix?

Answer 34

The fornix is the major output pathway from the hippocampus.

Question 35

What is the tectum?

Answer 35

The tectum consists of 4 colliculi that is found in the dorsal part of the midbrain.

It is involved in involuntary responses (reflexes) to auditory and visual stimuli.

Question 36

What are the cerebellar tonsils?

Answer 36

Part of the cerebellum that can herniate and compress the medulla.

Question 37

What produces CSF?

Answer 37

Choroid plexus found in the ventricles (mainly lateral ventricles).

They produce around 600-700 ml of CSF every day.

Question 38

Functions of the CSF.

Answer 38

Metabolic properties as well as mechanical functions such as cushioning the brain.

Also renders the brain weightless in its cavity.

This means without the CSF it would appear heavy and herniate into foramen magnum.

Question 39

Functions of the ventricles.

Answer 39

Producing CSF

Question 40

Where is the CSF reabsorbed?

Answer 40

At the arachnoid granulations (and some other sites).

Question 41

Explain the course of CSF.

Answer 41

Made mostly in the lateral ventricles.

It will the drain via the interventricular foramen.

It will then reach the third ventricle which is squashed between the two thalami.

It continues its course via the cerebral aqueduct into the fourth ventricle and will then drain into either the lateral foramen och Luschka, foramen of Magendie or the central canal.