week 1- protection of the brain

Question 1

the brain is protected by…

Answer 1

• cranium (skull)
• meninges
• blood brain barrier
• cerebrospinal fluid

Question 2

what does the cranium do?

Answer 2

encloses brain to protect it from mechanical force

Question 3

what are the meninges?

Answer 3

3 connective tissue membranes that cover external surface of brain and spinal cord

Question 4

what is each membrane of the meninges called?

Answer 4

mater

Question 5

what is the outermost membrane of the meninges called?

Answer 5

dura mater

Question 6

what is the middle membrane of the meninges called?

Answer 6

arachnoid mater

Question 7

what is the innermost membrane of the meninges called?

Answer 7

pia mater

Question 8

what is outer dura mater?

Answer 8

strong, protective membrane that is double layered

Question 9

what is the outer layer of the dura mater called?

Answer 9

periosteal layer

Question 10

what does the outer periosteral layer attach to?

Answer 10

attaches directly to the inner surface of skull

Question 11

what does the inner meningeal layer cover?

Answer 11

external surface of the brain

Question 12

the two dural membranes are fused together but in areas where they seperate they enclose…

Answer 12

dural sinuses

Question 13

what are dural sinuses?

Answer 13

channels that drain venous blood from the brain

Question 14

what is dural folds(septa)?

Answer 14

tough, inward folds the help hold brain in position and prevent excessive movement

Question 15

what is the arachanoid mater seperated from the dura mater with?

Answer 15

subdural space

Question 16

what is the cavity found beneath the arachnoid membrane?

Answer 16

subarachnoid space

Question 17

what does the subarachnoid space contain?

Answer 17

cerebrospinal fluid

Question 18

what does cerebrospinal fluid do?

Answer 18

cushions brain further protecting from mechanical forces

Question 19

what is pia mater?

Answer 19

very thin membrane that clings to surface of the brain

Question 20

what does pia mater contain?

Answer 20

small blood vessels that supply oxygen and nutrients to brain and spinal cord

Question 21

what does cerebrospinal fluid do?

Answer 21

• floats brain, reducing weight
• nourishes
• shock absorbing medium

Question 22

how does CSF nourish the brain?

Answer 22

nourishes neural tissue and removes waste, functions as a diffusion medium between blood and neural tissue

Question 23

where is CSF produced?

Answer 23

within the four ventricles of the brain by choroid plexus

Question 24

what are the four ventricles of the brain interconnected with?

Answer 24

each other and central canal of spinal cord

Question 25

where are the lateral ventricles found in the brain?

Answer 25

within each cerebral hemisphere

Question 26

where is the third ventricle found in the brain?

Answer 26

diencephalon

Question 27

where is the fourth ventricle found in the brain?

Answer 27

between cerebellum and brain stem

Question 28

what is the choroid plexus?

Answer 28

a cluster of capillaries surrounded by ependymal cells, that are joined together by tight junctions. Produce CSF

Question 29

once CSF is produced how does it flow?

Answer 29

1. through venticles
2. circulates through subarachanoid space, spinal meninges and through central canal
3. is absorbed into dural sinuses via arachnoid villi

Question 30

what does the blood-brain barrier do?

Answer 30

protects neural tissue from harmful substances and pathogens circulating in blood

Question 31

what does the blood brain barrier mainly consist of?

Answer 31

endothelial cells and ‘feet’ processes of astrocytes

Question 32

what is the blood-brain barrier permeable to?

Answer 32

• lipid soluble: oxygen, carbon dioxide, lipids, alcohol, nicotine and anaesthetics
• nutrients such as glucose

Question 33

what is the blood-brain barrier impermeable to?

Answer 33

metabolic wastes, proteins, toxins, potassium ions, most drugs and antibiotics

Question 34

how many arteries ascend the neck to deliver blood into cranium?

Answer 34

four

Question 35

what four arteries ascend the neck to deliver blood into the cranium?

Answer 35

• right/left internal carotid arteries (either side of neck)

- right/left vertebral arteries (back of neck either side of vertebral column)

Question 36

once blood is inside the cranium how many cerebral arteries supply blood to the cerebellum?

Answer 36

six