The Cerebrum

Question 1

The brain weighs

Answer 1

about 3 pounds
skull+brain weigh 11-14 pounds

2% body weight
20% body energy

Question 2

The function of the brain is not related to ___

Answer 2

size.
But is related to number & organization of neurons

Question 3

2 hemispheres of the brain

Answer 3

82% of brain’s mass

Question 4

The cerebral cortex is made of

Answer 4

• Neuronal cell bodies (gray matter)
• Neuronal axons below (white matter)

Question 5

The meninges

Answer 5

3-layer membrane surrounds delicate brain

Question 6

Layers of meninges

Answer 6

• dura mater (tough mother)
• arachnoid mater (spider mother)
• Pia matter (faithful mother)

Question 7

Dura mater

Answer 7

• Made of 2 layers (external/internal)
• Bound together except where they form sinuses
• allow CSF

Question 8

Longitudinal Fissure

Answer 8

separates cerebral hemispheres

Question 9

tentorium cerebelli

Answer 9

separates occipital from cerebellum

Question 10

falx cerebelli

Answer 10

separates hemispheres of cerebellum

Question 11

Function of meninges

Answer 11

Protects the brain
- shock absorber
- anchor CNS to limit brain movement
- support system blood vessels, nerves, lymphatics, and CSF

Question 12

Where there are layers..

Answer 12

there are spaces

Question 13

Types of spaces

Answer 13

• epidural
• subdural
• subarachnoid

Question 14

Epidural space

Answer 14

between skull & dura mater
- spinal cord space between dura mater bones in vertebral column
- space analgesics/anesthesia injects

between 1+2 lumbar vertebra, spinal cord ends and only CSF - location lumbar puncture

Question 15

Subdural space

Answer 15

between dura mater & arachnoid mater
- normal conditions not a space
- opened up if brain bleeds from trauma (subdural hematoma) which causes damage/possible stroke

Question 16

What to do with subdural hematoma

Answer 16

mechanical compression and increase pressure

Question 17

Subarachnoid space

Answer 17

between arachnoid and pia mater
- filled CSF, cushions & protects brain

Question 18

Blood Brain Barrier (BBB)

Answer 18

highly selective, semi-permeable membrane

• lines blood vessels in brain
• acts as filter to protect CNS
• regulates which substances can pass through bloodstream into brain
• form tight packed specialized cells – form barriers around brain capillaries

Question 19

blood is toxic to brain cells

Answer 19

blood and braincells touching can lead to cell death

Question 20

Functions of BBB

Answer 20

• protects against foreign invaders and hormones/neurotransmitters in body
• maintains constant environment for brain (homeostasis)

Question 21

BBB problems

Answer 21

• hypertension (high BP)
• developmental problems with BBB
• Hyperosmolality (increased levels of sodium or glucose)
• microwaves, radiation, infection, trauma, ischemia, inflammation, pressure

Question 22

Circumventricular Organs (CVO)

Answer 22

Series of structures located around ventricular stystem (highly vascular (lack BBB))

link CNS, VS, Endocrine Sys: creating alternate route for hormones/neuropeptides

Question 23

function of CVOs

Answer 23

sensory: monitor presence of toxic substances

secretory: secrete hormones (pineal & pituitary)

Question 24

Toxins that cross BBB

Answer 24

• lead/mercury/iron
• alcohol/nicotine/caffeine
• some bacteria (meningitis)
• highly lipid soluble molecules
• diseases (cancer)

can limit crossover of some drugs (dopamine)

Question 25

the brain consumes

Answer 25

20% of body’s oxygen

Question 26

blood enters the brain through

Answer 26

carotid arteries
vertebral arteries
(these feed the circle of Willis)

Question 27

Aorta

Answer 27

begins in low left chamber of heart
- extends up toward head
- 3 branches off aortic arc

Question 28

branches off Aortic arc

Answer 28

1. Brachiocephalic trunk/artery (innominate)
2. Left Common Carotid artery
3. Left Subclavian artery

Question 29

Circle of Willis

Answer 29

circular array of blood vessels

Question 30

arteries leading INTO circle of willis

Answer 30

• bilateral internal carotid
• basilar (merging of vertebral arteries)

Question 31

arteries leading OUT OF circle of willis

Answer 31

• posterior cerebral artery PCA
• middle cerebral artery MCA
• anterior cerebral artery ACA

CEREBRAL BLOOD SUPPLY IS FROM THESE

Question 32

Anterior cerebral artery ACA

Answer 32

medial & superior parts of frontal lobe
anterior parietal lobe

divided into 2 groups: central & cortical

Question 33

Middle cerebral artery MCA

Answer 33

• substantial portions of cerebrum
• bulk of lateral surface of cerebrum, parts of frontal, temporal, parietal lobes

Question 34

branches of Middle Cerebral Artery

Answer 34

Superior: portions of motor strip, premotor area, left hemisphere, brocas

Inferior: postcentral gyrus, wernickes

Question 35

Posterior cerebral artery PCA

Answer 35

occipital lobe, postermedial temporal lobes, midbrain, thalamus, choroid plexus, parts of lateral/3rd ventricles

central & cortical branches

Question 36

Vertebral basilar system

Answer 36

blood supply to thalamus, cerebellum, occipital lobes, brainstem, and cervical spinal cord

Question 37

Branches of Vertebral artery

Answer 37

• Posterior inferior cerebellar artery (PICA)
• Basilar artery

Question 38

Posterior inferior cerebellar artery (PICA)

Answer 38

largest branch of vertebral artery
supplies critical regions of medulla, 4th ventricle and cerebellum

Question 39

Basilar Artery

Answer 39

main artery supplies blood to posterior brain (brainstem, cerebellum, occipital lobes)

Question 40

the Basilar Artery divides into

Answer 40

Anterior inferior cerebellar artery (AICA)
Superior cerebellar
Posterior cerebellar

Question 41

Venous System

Answer 41

(removal system)
- Moves deoxygenated blood away
- Removed thru 4 sinuses in meninges

• Superficial & deep cerebral veins then remove

Question 42

4 sinuses in meninges

Answer 42

superior sagittal
transverse
occipital
sigmoid