Lecture 2- Meninges, CSF, Ventricular system, Cerebral hemispheres

Question 1

3 brain coverings

Answer 1

Dura mata
- subdural spaces (increased arteries)
Arachnoid mata
- subarachnoid space (CSF and increased veins)
Pia mata
- adheres directly onto brain

Question 2

Dura mata layers

Answer 2

Fibrous endosteal
Meningeal
- dural venous sinuses in between some sites

Question 3

Dural reflections

Answer 3

Falx cerebri (partial separation of cerebral
hemispheres)
Falx cerebelli (partial separation of cerebellar
hemispheres)
Tentorium cerebelli
Diaphragm sellae

Question 4

Blood supply of dura

Answer 4

Ethmoidal artery (ant + post)
Internal carotid artery
Middle meningeal artery
Maxillary artery
Ascending pharyngeal artery
Occipital artery 
Vertebral artery

Question 5

Nerve supply of dura mata

Answer 5

Meningeal branches of

• Maxillary
• Mandibular
• Upper cervical nerves

Question 6

Arachnoid mata

Answer 6

Thin, vascular membrane
Attaches to dura by several layers of flattened cells
Conforms to general shape of brain but does not fit into every sulcus
Separated from Pia by arachnoid trabeculae and subarachnoid space

Question 7

Specialisations of arachnoid mata

Answer 7

Trabeculae
Villi
Barrier

Question 8

Arachnoid trabeculae

Answer 8

Strands of collagenous connective tissue from arachnoid to pia

Question 9

Arachnoid villi

Answer 9

For reabsorption of CSF
Outgrowths of arachnoid projecting through the dura into the sinuses
Form granulations with age

Question 10

Arachnoid barrier

Answer 10

Cells of outermost arachnoid layer have tight junctions

Prevents spread of microbes from the dura into the subarachnoid space so that they don’t reach the brain

Question 11

Pia mata

Answer 11

2-3 cells thick
Attaches to end feet of arachnoid trabeculae, helps to keep arachnoid space open
Closely follows all sulci and gyri of brain
Penetrated by arteries and veins when they enter or leave the brain substance (perivascular space)

Question 12

Spinal meninges

Answer 12

Devoid of fibrous layer (endosteal) of dura which ends at margin of foramen magnum
Arachnoid mata stays relatively the same
Pia mata forms 21 pairs of denticulate ligaments and is thickened anteriorly to give a shiny appearance in the midline (linea splendens and filum terminale)

Question 13

Ventricular system

Answer 13

Lateral ventricles (cerebrum) via intraventricular foramen to
3rd ventricle (diencephalon) via cerebral aqueduct to
4th ventricle (pons/medulla)

Question 14

Parts of lateral ventricle

Answer 14

Anterior (frontal
Body
Posterior (occipital)
Inferior (temporal)

Question 15

Walls of 3rd ventricle

Answer 15

Anterior wall
Posterior wall
Sides= Thalamus
Roof
Floor

Question 16

Floor of 4th ventricle (Rhomboid Fossa)

Answer 16

Facial colliculus
Inferior cerebral peduncle
Hypoglossal trigone
Vagal trigone
Locus cerulus
Stria medularis
Cuneate tubercle
Gracile tubercle

Question 17

CSF formation

Answer 17

Produced by choroid plexus
Made in the floor of lateral ventricles and roof of 3rd + 4th ventricles
Made at rate of 0.35 ml/min
500 ml of total CSF made per day and replaced every 4-6 hours

Question 18

Circulation of CSF

Answer 18

From lateral vent to 3rd vent via interventricular foramina of Monro

From 3rd vent to 4th vent via cerebral aqueduct of Sylvius

From 4th vent to subarachnoid space via median foramen Magendie (Cisterna Magna + lateral foramina of Luschka, and Pontine Cistern)

Question 19

Absorption of CSF

Answer 19

Absorbed into dural venous sinuses through arachnoid villi/granulations
CSF has a higher pressure than venous blood (passive transfusion)
Arachnoid villi/granulations are a one-way valve, therefore collapse to prevent venous blood from entering subarachnoid space

Question 20

Functions of CSF

Answer 20

Supports and cushions brain and spinal cord against trauma for shock absorption
Acts as a buoyant fluid, therefore allowing brain to weigh less
Maintains uniform pressure
Aids brain nutrition, choroid plexus secretes protein-rich CSF for neural tissues
Removes waste products of neural metabolism

Question 21

Cerebrospinal cisterns and types

Answer 21

Sites of dilation of subarachnoid space with pooling of CSF
Cerebello-medullary 
Pontine 
Interpenduncular
Cistern Ambiens

Question 22

Cerebello-medullary cistern

Answer 22

Largest cistern

Question 23

Pontine cistern

Answer 23

Contains basilar artery

Question 24

Interpenduncular cistern

Answer 24

Contains arterial circle of Willis
Pre- and post- chiasmic
Cisterna of lamina terminalis
Supracallosal cistern

Question 25

Cistern ambiens

Answer 25

Between corpus collosum and cerebellum

Contains great cerebral vein and pineal gland

Question 26

Obstruction of CSF circulation

Answer 26

Increased intraventricular pressure
Retinal veins become dilated
Optic nerve disc pushed forward above level of retina (papilloedema- choked disc)

Question 27

Hydrocephalus

Answer 27

Excess CSF, therefore increased pressure

Congenital or acquired

Question 28

Occipital lobe position

Answer 28

Lies post to line joining pre-occipital notch to parietal-occipital sulcus (medial surface)
Lateral occipital sulcus

Question 29

Functions of frontal lobe

Answer 29

Motor and pre-motor cortical regions
Broca’s area for voluntary speech
“Associational” type cortex involved in executive functioning, goal-directed behaviours, personality etc

Question 30

Functions of parietal lobe

Answer 30

Somatosensory
Certain aspects of visual/auditory/somatic association
Visual/somatic association (the where aspect)

Question 31

Functions of temporal lobe

Answer 31

Auditory
Auditory-visual associations
Visual sensations
Wernicke’s area

Question 32

Functions of occipital lobe

Answer 32

Only visual sensation is processed
fine grade visual discrimination
Primary visual cortex
Secondary visual cortical areas

Question 33

Functions of insular lobe

Answer 33

Poorly understood region

Associated with taste, vestibular, visceral sensation, secondary somatic and auditory