Features of the brain, Meninges, Blood Supply, CSF flow

Question 1

What are the following lobes responsible for:

(1. ) Frontal
(2. ) Parietal
(3. ) Temporal
(4. ) Occipital

Answer 1

(1. ) Frontal = Voluntary movement of the opp side of body, dominant hemisphere controls speech and writing, intellectual functioning, thought process, reasoning and memory
(2. ) Parietal = Receives and interprets sensation including pain, touch, pressure, size, shape
(3. ) Temporal = Understanding spoken words and sounds, memory and emotion
(4. ) Occipital = Understanding visual info and meaning of written words

Question 2

Where would you find Broca’s area and what is the importance of it?

Answer 2

(1. ) inferior frontal gyrus of the dominant hemisphere
(2. ) Area is important for speech production, motor control of facial + tongue muscle
(3. ) Sx of Broca’s Aphasia
- Difficulty in speaking
- Problems with reading + writing

Question 3

Where would you find Weirnicke’s area and what is the importance of it?

Answer 3

(1. ) Temporal Lobe
(2. ) Area is important for comprehension of spoken and written language
(3. ) Sx of Aphasia
- ability to grasp meaning of spoken words and sentences is impaired
- h/e production of speech is not very affected
- ‘meaningless speech’

Question 4

Describe function of the dura mater

Answer 4

(1. ) Dura forms folds and partitions the brain, and divide the cranial cavity into several compartments.
(2. ) Space between endosteal and meningeal layers forms the dural venous sinuses

Question 5

Describe all the dural venous sinuses

Answer 5

(1. ) Superior sagittal sinus
(2. ) Straight sinus
(3. ) Inferior sagittal sinus
(4. ) Transverse sinus
(5. ) Sigmoid sinus
(6. ) Confluence of sinuses

Question 6

Describe the dural folds

Answer 6

(1. ) Falx cerebri = within longitudinal fissure
(2. ) Tentorium cerebri = separates cerebellum from occipital lobe
(3. ) Falx cerebelli = separates cerebellum lobes
(4. ) Diaphragm Sellae = surrounds the sellicae turnica

Question 7

What is the cavernous sinus? and what may be found within it?

Answer 7

(1. ) It is a paired dural venous sinus that lies lateral to the body of the sphenoid
(2. ) It houses CN3, 4, 6, V1, V2 and ICA

Question 8

What is a Cavernous Sinus Thrombosis?

Answer 8

(1. ) Infection such as sinusitis can travel to the cavernous sinus
(2. ) Blood clot develops to prevent the infection spreading any further
(3. ) H/e this can prevent venous drainage from the brain causing oedema and RICP

(4. ) Sx
- Sharp, severe headache
- Seizures
- Focal, motor deficit
- Dec consciousness

Question 9

What is found within the subarachnoid space ?

Answer 9

(1. ) The is the space between the arachnoid and pia mater

(2. ) CSF, arteries, veins are found within this space

Question 10

What is the function of the PIA mater?

Answer 10

It is part of the BBB that comprises of: capillaries endothelialium, basement mb, astrogenic end feet

Question 11

Describe function of the arachnoid mater

Answer 11

(1. ) Forms subarachnoid space

(2. ) Forms arachnoid granulations that allows for CSF to be drained into the venous system

Question 12

What produces CSF, and what is the function of CSF (4) ?

Answer 12

(1.) Choroid Plexus

Function of CSF

(1. ) Cushions and nourishes the brain
(2. ) Protects it against from blow to the head
(3. ) Buoyancy
(4. ) chemical stability

Question 13

Describe the flow of CSF from ventricular system to venous system

Answer 13

Lateral ventricles –> intraventriuclar foramen –> 3rd ventricle –> cerebral aquaduct –> 4th ventricle –> lateral and medial aperture –> subarachnoid space + SC –> arachnoid villi –> superior sagittal sinus –> IJV

Question 14

What is hydrocephalus?

Answer 14

(1. ) Blockage of CSF flow e.g. tumour or adhesion, causes increased pressure so ventricles swell.
(2. ) Sx of RICP = headache, unsteadiness, mental impairment
(3. ) Mx = Shunt to peritoneum or jugular vein

Question 15

What makes up the anterior blood circulation?

Answer 15

(1. ) branches arise from internal carotid artery

(2. ) anterior and middle cerebral arteries form the anterior circulation that supplies the forebrain

Question 16

What makes up the posterior blood circulation?

Answer 16

(1. ) Posterior circulation is supplied by the vertebral arteries which enters via foraman magnum
(2. ) This gives rise to the basilar artery which then divides into the posterior cerebral arteries.
(3. ) Basiliar also gives rise to pontine, superior cerebellar and posterior-inferior cerebellar arteries

Question 17

What do the cerebral arteries supply

Answer 17

ACA = Anterior-medial
MCA = Lateral 
PCA = Posterior

Question 18

What is a berry anneurysms

Answer 18

(1. ) Points of weakness that can lead to aneurysm formation
(2. ) Commonly at the branching points e.g. anterior communicating a.
(3. ) Ruptures can lead to SAH or intracerebral haemorrhage

Question 19

What is a Stroke?

Answer 19

• Can be ischaemic or haemorrhagic

- Rapid onset of focal neuroloigcal deficets lasting >24hrs (if <24hrs this is a TIA)

Question 20

What is Amaurosis Fugax?

Answer 20

• temporary loss of one eye
• cause: carotid thrombosis occuldes central retinal artery
• risk of stroke

Question 21

Extradural haemorrhage

Answer 21

(1. ) High pressure bleed from meningeal arteries causes RICP
(2. ) Typically after head injury, fractured skull

Question 22

Subdural haemorrhage

Answer 22

(1. ) Low pressure bleed from bridging veins. This can form a haematoma which can cause RICP
(2. ) Crescent shape is seen on CT scan.

(3. ) Causes:
- Severe head injury = car crash, fall
- Minor head injury = older age, blood-thinning medication, drink excessively

Question 23

SAH

Answer 23

(1. ) Berry anneurysm of CoW
(2. ) Blood surrounds and fills sulci
(3. ) Sx = Thunderclap headache, photophobia, high mortality

Question 24

What is an intracerebral haemorrhage?

Answer 24

(1.) Small vessels and microanneurysms leading to bleeding within brain tissue