Topography the Brain Flashcards

1
Q

Some main regions of the brain:

A

Cerebrum (two hemispheres)
Diencephalon (contains thalamus and hypothalamus)
Brainstem (Midbrain - Pons - Medulla)
Cerebellum

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2
Q

Where are the ventricles found in the brain?

A

2 Lateral Ventricles are found within the cerebral hemispheres

The 3rd ventricle is found within the diencephalon

The cerebral aqueduct is contained within the midbrain

The 4th Ventricle is post to the pons & medulla and anterior to the cerebellum

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3
Q

What is contained within the ventricles?

A

CSF

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4
Q

Where is CSF made, travel and absorbed

A
  • Produced in choroid plexus of ventricles
  • Passes into subarachnoid space through foramina in the roof of the 4th ventricle
  • Absorbed by arachnoid villi
  • Passes into the sagittal sinus
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5
Q

What arteries supply the brain?

A

The ICAs & Vertebral Arteries

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6
Q

What is the function of the circle of willis and what arteries feed into it?

A

The circle of willis compensates for one vessel to the brain being blocked by allowing others to supply the same area.

Its fed by the two ICAs and the basilar artery (which is made by the 2 vertebral arteries)

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7
Q

What major vessels come off the circle of willis?

A

Anterior Cerebral Artery
Middle Cerebral Artery
Posterior Cerebral artery

Its worth noting there is no more anastomosis after the circle of willis (they are end arteries), so any blockage in this arteries or their branches will cause ischaemic stroke

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8
Q

Which artery supplies which part of the brain?

A

Brainstem - Basilar Art
Cerebellum - Basilar Art

Cerebrum:

  • Ant Cerebral Art supplies the medial aspect
  • Middle Cerebral Art Supplies the lateral aspect
  • Posterior cerebral Art supplies the occipital lobe and much of the inferior aspect
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9
Q

Describe the venous drainage of the brain?

A

Superficial veins

  • > Deep Veins
  • > Venous Sinuses
  • > Internal Jugulars
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10
Q

Where do the venous sinuses lie?

A

Between layers of dura mater

Dura mater is two layers its just they’re always fused except at venous sinuses

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11
Q

What are the major venous sinuses of the brain?

A
Cavernous sinus 
Superior & Inf Sagittal Sinuses
Transverse Sinus
Straight Sinus
Sigmoid Sinus
Sup & Inf Petrosal Sinuses

Can you locate them all?

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12
Q

Where is the cavernous sinus?

A

Between the sphenoid and temporal bones.

Basically just under/lateral to the sella turcica

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13
Q

Where is the transverse sinus?

A

Runs in a transverse plane against the inf surface of the occipital bone

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14
Q

Where is the sigmoid sinus?

A

Curves in an S shape behind the petrous temporal bone.

It drains from the transverse sinus and becomes the IJV at the jugular foramen

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15
Q

What cranial nerves are given off by the brainstem?

A

III –> XII

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16
Q

What is the function of the brainstem?

A
  • Give off cranial nerve 3-12
  • Pathway for tracts running from higher brain centres
  • Contains vital centres (Respiratory, cardiovascular)
17
Q

How is the brainstem attached to the cerebellum?

A

By the Cerebellar Peduncle which is split into 3:

  • Meddulla = Inf Cerebral Peduncle
  • Pons = Middle Cerebral Peduncle
  • Midbrain = Sup Cerebral Peduncle
18
Q

Which section of the brainstem gives out which cranial nerves?

A

Higher the brainstem lower the cranial nerve.

Midbrain - 3 & 4
Pons - 5 –> 8
Medulla - 9 –> 12

19
Q

What are the important surface features of the medulla?

A

Pyramidal projections run down the front of the medulla, they are motor fibre tracts.

The olives lateral to the pyramids at the top of the medulla

20
Q

What happens to the medullla’s pyramids near the bottom?

A

Near the bottom of the medulla the pyramids cross over.

This is called the Decussation of the Pyramids

21
Q

What ventricle is related to the brainstem?

A

TWO!
Midbrain contains the cerebral aqueduct

The pons & medulla are ant to the 4th ventricle

22
Q

Which cranial nerve is the only one to originate posteriorly?

A

The 4th (Trochlear) from the midbrain

23
Q

What is the important surface anatomy of the midbrain?

A

Posteriorly you can see the sup & Inf Colliculi which are involved in the visual and auditory reflex

24
Q

Function of the cerebellum?

A

Co-ordination and movement

25
Q

Function of the Diencephalon?

A

Thalamus - Acts as a sensory relay centre

Hypothalamus - Involved in regulating the ANS, hormones, temperature and circadian rhythm

26
Q

What makes up the Diencephalon?

A

A number of paired structures:

  • Thalamus
  • Hypothalamus
  • Pituitary
  • Epithalamus (pineal Gland)
27
Q

Whats the function/location of the thalamus

A

Its egg shaped on either side of the 3rd ventricle

Made up of ant/medial/lateral nuclei groups

Acts as a sensory relay station

28
Q

Whats the function of the hypothalamus?

A

Below thalamus separated by the hypothalamic sulcus

Its essential for homeostasis:

  • Controls the autonomic system
  • Regulates body temp
  • Regulates hunger and thirst
  • Regulates sleep-wake cycle
  • Controls the endocrine system
29
Q

Describe the structure of the cerebellum?

  • Lobes
  • Surface
  • Connections to rest of brain
A
  • Two hemispheres connected by a vermis
  • Each hemisphere is split into ant/post/flocculonodular lobe
  • Surface covered in sulci & Folia (Gyri)
  • Connected to brainstem by inf/middle/sup cerebellar peduncles
  • Undersurface has attached cerebellar tonsils
30
Q

Whats the function of the cerebellum?

A

It gets info on proprioception, balance, posture and from the brain motor intention

Then it works out force, direction, extent of contraction to ensure smooth coordinated movement while maintaining posture and feeds it back to the cerebral cortex.

I.e. it fine tunes movement and maintains posture

31
Q

What happens if theres damage to the cerebellum?

A

Ataxia - A lack of smooth voluntary muscle contraction

So the person can still make movements but without fine control so cant do:

  • Finger Nose test
  • Knee Heel Test
  • Walking in a straight line
32
Q

What connects the brainstem and the cerebrum?

A

The midbrain includes the cerebral peduncles which connect the pons to the thalami (and through that to the cerebrum)

33
Q

What vessels come off the basilar artery?

A

Cerebellar
The Superior cerebellar and Anterior Inferior Cerebellar come of the Basilar itself

The Posterior Inferior comes off the vertebral arteries prior to fusing to form the basilar artery