1 - Introduction to Functional Organisation of the CNS

Question 1

Can CT and MRI distinguish between grey and white matter?

Answer 1

Yes

Question 2

Imaging type that can visualise only white matter

Answer 2

Diffusion weighted MRI

Question 3

*Orientations of primate brain

Answer 3

BRAIN DIRECTIONS

Question 4

Name for fissure between lobes of brain

Answer 4

Longitudinal fissure

Question 5

Name for ridges of the cerebrum

Answer 5

Gyri/gyrus

Question 6

Name for grooves in cerebrum

Answer 6

Sulci/sulcus

Question 7

Organisation of the cerebral cortex

Answer 7

Four divisions (frontal, temporal, parietal, occipital. Not functionally very useful distinctions.

Question 8

Brain areas based on cellular differences

Answer 8

Brodmann areas. Largely functionally significant

Question 9

*Which kind of brain imaging produced this image?

Answer 9

PET scan

Question 10

What determines the histological layered structure of the brain?

Answer 10

Different neuron morphologies

Question 11

Proportion of brain’s neurons in the cerebellum

Answer 11

~70% of all neurons in brain

Question 12

Basic role of the cerebellum

Answer 12

Compares what your body wishes to do (in terms of movement) with what the muscles are actually doing. Makes movement more smooth. Also learning motor function.

Question 13

Location of basal ganglia

Answer 13

In telencephalon

Question 14

Role of basal ganglia

Answer 14

Selects, initiates voluntary movements. Form loops with cortex (for execution)

Question 15

What does damage of basal ganglia lead to?

Answer 15

Parkinson’s, Huntington’s diseases. Movement disorders.

Question 16

Striatum

Answer 16

Caudate and putamen

Question 17

Where in the brain are the thalami?

Answer 17

Diencephalon

Question 18

Role of thalami

Answer 18

Sensory relay between body and cortex

Question 19

Three different ways in which thalamic nuclei can project

Answer 19

1. Relays sensory information to specific areas of cortex 2. Relays of non-sensory information from cortex and basal ganglia to specific areas of cortex 3. Project globally to cortex; arousal, sleep

Question 20

Where in the brain is the hypothalamus?

Answer 20

Below thalamus, on the ventral surface of the brain (bottom part)

Question 21

Gland hanging from the hypothalamus

Answer 21

Pituitary gland

Question 22

Role of hypothalamus

Answer 22

Regulates homeostasis (temperature, blood volume and pressure, ion concentration, pH, O2 and glucose)

Question 23

Role of brainstem 1 2 3 4

Answer 23

1) Facial muscles 2) Sensation from face, head 3) Cardiorespiratory control 4) Arousal, sleep/wake cycle

Question 24

*Gross organisation of the spinal cord

Answer 24

Question 25

Changes in spinal cord shape over length

Answer 25

Divided into cervical, thoracic, lumbar and sacral regions. Enlarged at lower cervical and lumbar regions (for innervation of limbs).

Question 26

\*Shape of spinal cord over length

Answer 26

Question 27

Where does the spinal cord end?

Answer 27

~L1/L2 boundary

Question 28

Organisation of spinal nerves

Answer 28

Each spinal segment gives rise to a pair of spinal nerves

Question 29

How do spinal nerves leave the spinal cord?

Answer 29

Each formed by dorsal and ventral roots from the spinal cord, which fuse to form spinal nerve

Question 30

Role of ventral root

Answer 30

Exclusively motor (control skeletal muscle)

Question 31

Role of dorsal root

Answer 31

Exclusively sensory.

Question 32

Location of dorsal root ganglia

Answer 32

Hidden between vertebrae

Question 33

Role of dorsal root ganglia

Answer 33

Location of cell bodies of primary sensory afferent neurons

Question 34

Organisation of neurons in dorsal root ganglia

Answer 34

Cell body location in DRG. Splits into two axons. One goes to periphery, innervates site. Other branch enters dorsal horn via dorsal root

Question 35

Composition of most peripheral nerves

Answer 35

Mixed sensory and motor axons

Question 36

Number of ventricles

Answer 36

Two lateral ventricles, one third, one fourth, cerebral aqueduct

Question 37

Clinical importance of ventricles

Answer 37

Used to orientate the brain on an MRI, CT

Question 38

What forms CSF?

Answer 38

Vascular choroid plexus. CSF is an ultrafiltrate of plasma.

Question 39

Where is the choroid plexus?

Answer 39

Surface of ventricles

Question 40

Where does CSF exit brain?

Answer 40

Fourth ventricle. Drains into the subarachnoid space

Question 41

Layers of meninges

Answer 41

Dura (thickest, outermost) Arachnoid (fibrous, middle) Pia (thinnest, innermost)

Question 42

Two extensions of meninges

Answer 42

Falx and tentorium

Question 43

Falx

Answer 43

Extension of meninges into longitudinal fissure

Question 44

Tentorium

Answer 44

Extension of meninges between cerebellum and occipital lobe

Question 45

Significance of falx and tentorium

Answer 45

Fix brain in place. If there is swelling somewhere in the brain, the brain becomes compressed, has to squeeze through a hole in the middle of tentorium