LEC 16 - Ventricular system and blood supply

Question 1

What are the three layers of the meninges.

Answer 1

dura mater, arachnoid mater, pia mater

Question 2

Define the dura mater and its characteristics.

Answer 2

tough outer layer

Question 3

How is the arachnoid mater structured and what is its function?

Answer 3

‘spider web’ and contains blood vessels

Question 4

Explain the role of the pia mater in relation to the brain.

Answer 4

innermost layer, ‘skin’, closest to the brain

Question 5

Describe the system of sinuses related to the dura mater.

Answer 5

The system of sinuses is formed by the duplication of dura mater plates

Question 6

How many layers does the dura mater have and what are they?

Answer 6

The dura mater has two layers: the periosteal layer (near bone), and the meningeal layer (closer to the brain)

Question 7

What are the two types of dural folds?

Answer 7

• falx cerebri
• tentorium cerebelli

Question 8

Describe venous return

Answer 8

The superior sagittal sinus drains deoxygenated blood and waste into the sigmoid sinus, which then directs it to the internal jugular vein, clearing it from the brain.

Question 9

Describe the function of cerebrospinal fluid (CSF) in the brain.

Answer 9

provides physical support and cushioning for the brain, serves an excretory function, and facilitates chemical communication.

Question 10

Define the ventricular system in the brain.

Answer 10

The ventricular system is a network of interconnected cavities filled with cerebrospinal fluid, including the lateral ventricles, third ventricle, and fourth ventricle.

Question 11

Describe the intraventricular foramen in the ventricular system

Answer 11

also known as the foramina of Monro.

Connects the lateral ventricles with the third ventricle

Question 12

Describe the cerebral aqueduct in the ventricular system

Answer 12

Also known as aqueduct of Sylvius connects the third ventricle to the fourth ventricle in the brain.

Question 13

Describe the central canal in the ventricular system

Answer 13

It is continuous with the fourth ventricle, runs down throughout the spinal cord

Question 14

Describe the role of cerebrospinal fluid (CSF) in the central nervous system.

Answer 14

CSF provides physical support by cushioning the CNS, acting as a ‘water jacket’ that reduces the effective weight of the brain, and it also helps maintain homeostasis in the absence of a lymphatic system.

Question 15

Define the choroid plexus in relation to cerebrospinal fluid (CSF).

Answer 15

The choroid plexus is the site of CSF production within the brain.

Question 16

How does cerebrospinal fluid (CSF) exit the ventricles?

Answer 16

CSF exits the ventricles through the medial and lateral apertures, which release it into the subarachnoid space.

Question 17

Describe the function of arachnoid granulations in the context of cerebrospinal fluid (CSF).

Answer 17

Arachnoid granulations serve as the exit site for cerebrospinal fluid (CSF)

Question 18

In the venous sinus describe the arachnoid villi

Answer 18

Arachnoid villi allow reabsorption of CSF into the dural venous sinuses

Question 19

describe the flow of cerebrospinal fluid (CSF) through the brain and spinal cord

Answer 19

1. CSF is secreted by the choroid plexus in each lateral ventricle.
2. It flows through the interventricular foramina into the third ventricle.
3. The choroid plexus in the third ventricle adds more CSF.
4. CSF flows down the cerebral aqueduct to the fourth ventricle.
5. The choroid plexus in the fourth ventricle adds more CSF.
6. CSF flows out via two lateral apertures and one median aperture.
7. It fills the subarachnoid space, bathing the brain and spinal cord.
8. CSF is resorbed into the venous blood at the arachnoid villi in the dural venous sinuses.

Question 20

Describe the circle of Willis

Answer 20

A network of arteries at the brain’s base provides backup blood flow, connecting front and back blood supplies to maintain circulation if a blockage occurs.

Question 21

Name the arteries that supply the brain areas

Answer 21

anterior cerebral artery

posterior cerebral artery

middle cerebral artery

Question 22

Describe anterior cerebral artery

Answer 22

supplies mainly medial surface of the frontal and parietal lobes

Question 23

Describe posterior cerebral artery

Answer 23

supplies mainly medial surface of the occipital love and basal surface of occipital and temporal lobes

Question 24

Describe middle cerebral artery

Answer 24

Supplies mainly lateral surface of all lobes

Question 25

Define Acquired Brain Injury (ABI).

Answer 25

Acquired Brain Injury (ABI) refers to all types of brain injury that occur after birth.

Question 26

Describe the types of incidents that can lead to brain injury.

Answer 26

Brain injury can result from stroke, traumatic brain injury (TBI), brain tumours, poisoning, infection and disease, near drowning or other anoxic episodes, and alcohol and drug abuse.

Question 27

Define stroke in the context of brain injury and what ischemia and haemorrhagic stroke is

Answer 27

stroke = blood flow to the brain is interrupted, leading to brain injury.

ischemia stroke = blood-deprived area, blood flow is obstructed

haemorrhagic stroke = bleeding area, a ruptured blood vessel leaks blood into brain

Question 28

Describe the relationship between occlusion and infarction in the brain.

Answer 28

Occlusion results in infarction of a predictable territory, with the location and size of the infarct relating to the site of occlusion along the artery.

Question 29

How does the location of an infarct affect neurological deficits?

Answer 29

Neurological deficits relate to the location of the infarct, as different areas of the brain control different functions.

Question 30

Identify the questions to consider when assessing a stroke.

Answer 30

1) Which artery was affected by the stroke? 2) Which brain structure is supplied by the affected artery? 3) What is the normal function of the specific brain structure? 4) What are the functional deficits?

Question 31

List potential functional deficits that may arise from a stroke.

Answer 31

Functional deficits can include motor impairment, speech difficulties, sensory loss, and cognitive challenges. They are dictated by location and severity of the injury

Question 32

Define primary injury in the context of brain damage.

Answer 32

Primary injury refers to the damage to brain structures and neurons that occurs at the moment of the initial impact.

Question 33

Describe secondary injury following a brain injury.

Answer 33

Secondary injury involves biochemical events that occur after the primary injury, which typically worsen the outcome of the injury.