H&N week 4- Cranial cavity

Question 1

Label this diagram of the arterial blood supply of the brain.

Answer 1

Question 2

Compare the 3 arterial blood supplies for the cerebal hemisphere.

Answer 2

Anterior cerebral artery- serves for the lower limbs.

Posterior Cerebral Artery- supplies the posterior hemisphere and the lower parts of the hemisphere.

Middle cerebral artery- This is the main continuation of the internal carotid & serves for the area of the brain involved in the sensory of the brain and the area for speech.

Question 3

Label this diagram of the meninges.

Answer 3

Question 4

What is the function of the superior cerebral vein?

Answer 4

This takes blood from the surface of the brain and discharges it into the sagittal sinus.

Question 5

WHat is the arachnoid mater?

Answer 5

This is one of the meninges that lies immediately deep to the dura mater and loosely covers the brain.

It gives off cobweb like strands that cross the subarachnoid space.

Question 6

What is the function of cerebral spinal fluid?

Answer 6

it bathes the brain and acts like a cushion to resist movement if someone has trauma to the head.

Question 7

Where do you find cerebral spinal fluid?

Answer 7

In the subarachnoid space.

Question 8

Where is cerebral spinal fluid made?

Answer 8

In the 4th ventricle in the brain.

Question 9

WHat is the Pia mater?

Answer 9

This is the deepest of the 3 layers of the meninges.

It is vascular, very thin and follows the surface of the brain.

Question 10

What is the superior sagittal sinus?

Answer 10

A large venous channel inside the attached falx cerebri.

Question 11

Where does the superior sagittal sinus begin and end?

Answer 11

It begins near the crista galli anteriorly

It ends by draining into the confluence of the sinus.

Question 12

What is the Falx cerebri

Answer 12

A large sickle shaped fold whcih is an extension of the meningeal layer of the dura to physically seperate the right and left cerebral hemispheres.

Question 13

What is the dura mater?

Answer 13

A dense layer of collagen that lines the inside of the vault.

Question 14

What are the two layers of the dura mater?

Answer 14

The external periosteal layer

and the

Internal Meningeal layer.

Question 15

What are the arachnoid villi?

Answer 15

These are strands that pass through the dura and into the lumen of the sinus.

These absorb CSF gradually into the sinus.

Question 16

What is the middle meningeal artery?

Answer 16

This is an artery that runs between the dura and bone which arises from the maxillary artery. (located under the pterion)

This supplies the dura mater.

Question 17

Compare the 3 types of brain haemorrhage

Answer 17

Extradural- caused by rupture of the middle meningeal artery. Blood gathers between the bone and the dura (putting pressure on the brain)

Subdural- Involves the cerebral vein. Blood gathers between the arachnoid and the dura.

Subarachnoid- This is caused by bleeding of the cerebral arteries. A berry anerusym bleeds into the subarachnoid space.

Question 18

Which brain haemorrhage causes loss of conciousness first?

Answer 18

The ruptured artery of an Extradural haemorrhage means there is greater blood flow & build up than the ruptured vein (lower blood pressure) of a subdural haemorrhage.

So conciousness loss is rapid in an extradural haemorrhage.

Question 19

What is a Berry aneursym?

Answer 19

This is an anerusym (swollen then burst artery) found at the circle of willis.

This anerusym bleeds into the subarachnoid space causing the CSF to be blood stained.

Question 20

What is the circle of willis?

Answer 20

This is the joining of several arteries at the bottom of the brain.

Question 21

Label this diagram of the cranial venous sinuses.

Answer 21

Question 22

What is a sinus?

Compare it to a vein?

Answer 22

A network of veins that sit in a cavity.

The walls are made of dura mater and lined by endothelim.

Question 23

What is the function of the superior and inferior petrosal sinus?

Answer 23

It joins the sagittal sinuses to the cavernous sinus.

Question 24

What is the confluence of sinus?

Answer 24

This is a connection between the straight sinus and the superior sagittal sinus.

Question 25

Where do you find the straight sinus?

Answer 25

This runs in the place where the falx meets the tentorium cerebelli.

Question 26

What is the tentorium cerebelli?

Answer 26

An extension of the dura mater that seperates the cerebellum from the inferior portion of the occipital lobes.

Question 27

How does the Right transverse sinus form?

Answer 27

When the superior sagittal sinus swings to the side.

Question 28

How does the left transverse sinus from?

Answer 28

When the straight sinus swings to the left.

Question 29

What is the jugular foramen?

Answer 29

This is the hole where the sigmoid sinus exits as the internal jugular vein.

Question 30

What is the sigmoid sinus?

Answer 30

What we call the transverse sinus when it changes direction to form an ‘s’ shaped bend.

Question 31

Why does cavernous sinus thrombosis occur?

Answer 31

The bacteria can reach the sinus by the sphenoidal emissary vein.

Because the slow blood flow in the sinus allows bacterial buildup.