Tri B - Central Nervous System

Question 1

Describe the Dura Mater

Answer 1

Tough and fibrous
2 layered;
Outer periosteal - thicker, close to cranial bones
Inner meningeal - forms infoldings

Question 2

Name and describe the infoldings of the Dura Mater

Answer 2

Falx Cerebri - separates the 2 cerebral hemispheres
Falx Cerebelli - separates the 2 hemispheres of the cerebellum
Tentorium Cerebelli - separates cerebrum and cerebellum

Question 3

Describe the Arachnoid Mater

Answer 3

Thin, web-like membrane - avascular
Can herniate through dura, forming arachnoid villi - filters CSF

Question 4

Describe the Pia Mater

Answer 4

Very delicate, highly vascular
Closely follows convolution of brain
Supports network of blood vessels - includes choroid plexuses

Question 5

Name the Spaces between cranial meninges

Answer 5

Extradural
Subdural
Subarachnoid

Question 6

Describe the Spaces between cranial meninges

Answer 6

Extradural - between skull and dura
- potential space
Subdural - between dura and arachnoid
- potential space - serous fluid
Subarachnoid - between arachnoid and pia
- true space; trabeculae, CSF
- arachnoid cisterns, large pools of CSF near fissures

Question 7

Describe the ventricular system

Answer 7

4 irregular shaped cavities
2 lateral, 3rd & 4th ventricles
CSF is produced by choroid plexuses - in walls of lateral and 4th, roof of 3rd

Question 8

Describe CSF (cerebrospinal fluid)

Answer 8

Similar composition to blood- glucose, plasma proteins, minerals

Question 9

What are the functions of CSF?

Answer 9

Support and protect the brain
Maintain pressure
Acts as a cushion/ shock absorber
Keep brain and spinal cord moist
Exchanges nutrients and waste

Question 10

Describe the flow of CSF

Answer 10

Lateral Ventricles
–> interventricular foramina
–> third ventricle
–> cerebral aqueduct
–> fourth ventricle
to either
–> foramina of Luschka & foramen of magendie
–> subarachnoid space
or
–> central canal of spinal cord

Question 11

Describe the cerebrum

Answer 11

Largest part of brain
Hemispheres joined by corpus callosum
Surrounds midbrain and diencephalon

Question 12

Describe the cerebral cortex

Answer 12

2-4 mm thick outer layer
- contains functional cell bodies
Contains folds and grooves

Question 13

Name and describe the different types of folds in the cerebral cortex

Answer 13

Gyri - exposed folds
Fissures - deepest grooves
Sulci - shallower grooves

Question 14

Name and describe the different types of signals processed in the cerebral cortex

Answer 14

Sensory - receive and interpret sensory impulse
Motor - initiate movement
Association - complex integrative function (memory, emotions, reasoning)

Question 15

Name and describe the different functional areas within the cerebral cortex

Answer 15

Frontal lobe - reasoning, planning, speech, movement
Parietal lobe - perception of stimuli; touch, temp, pain
Temporal lobe - auditory stimuli and memory
Occipital lobe - Aspects of vision

Question 16

Describe the cerebral white matter

Answer 16

Nerve fibres - 3 directions
Association fibres - transmit between gyri of same hemisphere
Commissural fibres- transmit from gyri of one hemisphere to corresponding
Projection fibres - transmit from cerebrum to lower brain and spinal cord

Question 17

Describe the Basal Ganglia

Answer 17

Groups of cell bodies - grey matter
-caudate nucleus
-lentiform nucleus
Relay stations
Imitation of fine motor control

Question 18

What happens if there’s damage to the basal ganglia

Answer 18

Movement becomes jerky, clumsy, uncoordinated

Question 19

Describe the diencephalon

Answer 19

Connects cerebrum to midbrain
Composed of hypothalamus and thalamus (structures that surround 3rd ventricle)

Question 20

Describe the Thalamus

Answer 20

Paired oval masses of grey & white matter
Situated of each side of 3rd ventricle
Approx. 3cm length
Primarily relay station for sensory impulses

Question 21

Describe the Hypothalamus

Answer 21

Composed of 12 pairs of nuclei
Links nervous to endocrine system via pituitary gland
Function: Homeostasis

Question 22

Describe the Brainstem

Answer 22

Contains; Midbrain, Pons, Medulla Oblongata
Controls breathing, heart rate
Reticular formation extends through brainstem

Question 23

Describe the Midbrain

Answer 23

Extends from pons to diencephalon - 2.5cm
Surrounds cerebral aqueduct
Contains both nucleus and tracts
Anterior - pair of fibre bundles - cerebral peduncles
Posterior - 4 rounded eminences - corporal quadrigemina

Question 24

Describe the Pons

Answer 24

2.5cm long
Bridge connecting spinal cord with brain
Contains both nucleus and tracts
Helps control of respiration

Question 25

Describe the Medulla Oblongata

Answer 25

3cm long
Contains all ascending/descending tracts
Anterior aspect - 2 “pyramids”
-Composed of largest motor tract
-Point where many nerves cross
Contains nuclei (controls breathing)

Question 26

Describe the Cerebellum

Answer 26

Butterfly shaped
Each hemisphere consists of lobes - posterior, anterior, flocculondular
Folia - grey matter ridges
Arbor vitae - white matter tracts below folia
Cerebellar nuclei - grey matter masses, give rise to nerve fibres that transmit impulses

Question 27

What is the function of the cerebellum and what does damage look like?

Answer 27

Controls posture, balance and coordination
Damage - ataxia - disruption of muscle coordination

Question 28

Name the 2 endocrine glands in the brain

Answer 28

Pineal Gland
Pituitary Gland

Question 29

Describe the Pineal Gland

Answer 29

Pea sized, protrudes from 3rd ventricle
Secretes melatonin
Starts to calcify in puberty

Question 30

Describe the Pituitary Gland

Answer 30

Pea sized
Secretes hormone control of other glands

Question 31

Describe the Limbic System

Answer 31

Ring of structures in inner border of cerebrum and floor of diencephalon
Primary role in emotions - pain, anger
- also involved in smell and memory
Contains:
Hippocampus - memory
Amygdala - rage
Mamillary bodies - olfaction

Question 32

Describe arterial blood supply within the brian

Answer 32

15% cardiac output
2 internal carotid arteries
2 vertebral arteries

Question 33

Describe the Circle of Willis

Answer 33

A ring of blood vessels
Located at base of brain
If on section is blocked, others can prevent tissue death

Question 34

Describe the Dural Venous Sinuses

Answer 34

Endothelial lined spaces between periosteal and meningeal layers of dura
Large surface veins empty here
All brain blood drains through internal jugular vein

Question 35

Name the Main Venous Sinuses

Answer 35

Superior Sagittal x1
Inferior Sagittal x1
Straight x1
Transverse x2
Sigmoid x2