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

1
Q

3 brain coverings

A
Dura mata
- subdural spaces (increased arteries)
Arachnoid mata
- subarachnoid space (CSF and increased veins)
Pia mata
- adheres directly onto brain
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2
Q

Dura mata layers

A

Fibrous endosteal
Meningeal
- dural venous sinuses in between some sites

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3
Q

Dural reflections

A

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

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4
Q

Blood supply of dura

A
Ethmoidal artery (ant + post)
Internal carotid artery
Middle meningeal artery
Maxillary artery
Ascending pharyngeal artery
Occipital artery 
Vertebral artery
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5
Q

Nerve supply of dura mata

A

Meningeal branches of

  • Maxillary
  • Mandibular
  • Upper cervical nerves
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6
Q

Arachnoid mata

A

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

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7
Q

Specialisations of arachnoid mata

A

Trabeculae
Villi
Barrier

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8
Q

Arachnoid trabeculae

A

Strands of collagenous connective tissue from arachnoid to pia

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9
Q

Arachnoid villi

A

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

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10
Q

Arachnoid barrier

A

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

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11
Q

Pia mata

A

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)

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12
Q

Spinal meninges

A

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)

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13
Q

Ventricular system

A
Lateral ventricles (cerebrum) via intraventricular foramen to
3rd ventricle (diencephalon) via cerebral aqueduct to
4th ventricle (pons/medulla)
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14
Q

Parts of lateral ventricle

A

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

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15
Q

Walls of 3rd ventricle

A
Anterior wall
Posterior wall
Sides= Thalamus
Roof
Floor
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16
Q

Floor of 4th ventricle (Rhomboid Fossa)

A
Facial colliculus
Inferior cerebral peduncle
Hypoglossal trigone
Vagal trigone
Locus cerulus
Stria medularis
Cuneate tubercle
Gracile tubercle
17
Q

CSF formation

A

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

18
Q

Circulation of CSF

A

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)

19
Q

Absorption of CSF

A

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

20
Q

Functions of CSF

A

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

21
Q

Cerebrospinal cisterns and types

A
Sites of dilation of subarachnoid space with pooling of CSF
Cerebello-medullary 
Pontine 
Interpenduncular
Cistern Ambiens
22
Q

Cerebello-medullary cistern

A

Largest cistern

23
Q

Pontine cistern

A

Contains basilar artery

24
Q

Interpenduncular cistern

A

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

25
Q

Cistern ambiens

A

Between corpus collosum and cerebellum

Contains great cerebral vein and pineal gland

26
Q

Obstruction of CSF circulation

A

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

27
Q

Hydrocephalus

A

Excess CSF, therefore increased pressure

Congenital or acquired

28
Q

Occipital lobe position

A

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

29
Q

Functions of frontal lobe

A

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

30
Q

Functions of parietal lobe

A

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

31
Q

Functions of temporal lobe

A

Auditory
Auditory-visual associations
Visual sensations
Wernicke’s area

32
Q

Functions of occipital lobe

A

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

33
Q

Functions of insular lobe

A

Poorly understood region

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