Support Structures

Question 0

Dura Mater

Answer 0

• “tough mother”

- thick outer layer immediately under bone

Question 1

Meninges

meningitis?

Answer 1

• 3 parts: Dura Mater, Arachnoid Mater, Pia Mater

- meningitis: inflammation of meninges

Question 2

Arachnoid Mater

Answer 2

• “Spider mother”
• spider-web like spongy layer
• Subarachnoid space filled with CSF (central spinal fluid)

Question 3

Pia Mater

Answer 3

• “pious mother”
• pliant inner layer
• conforms to brain and spine surface
• includes blood vessels

Question 5

CSF

Answer 5

• is drawn into Subarachnoid space of Meninges and Central Canal of spine
• helps to cushion, support (float) jellylike brain, protect Cord, provides reservoir of hormones and nutrition

has a half life of ~3 hours, drains from Subarachnoid space into veins, reabsorbed into blood

Question 6

Hydrocephalus

Answer 6

“water on the brain”

if flow from Ventricles is blocked

may be surgically drained

Question 10

Ventricles

Answer 10

• hollow, inter-connected cavities in the brain
• produce Cerebral Spinal Fluid (CSF)
• 2 lateral and third ventricles in Forebrain
• Cerebral Aqueduct in Midbrain
• Fourth ventricle in Hindbrain

Question 11

Blood Vessels

unconsciousness?

permanent brain damage?

Answer 11

a complex web of arteries (incoming) and veins (outgoing) feed (mainly glucose) and cleanse brain

supply cut off for 6 seconds -> unconsciousness

supply cut off for 4 - 6 minutes -> permanent brain damage

Question 12

Blood Brain Barrier

Answer 12

• semi-permeable barrier, provides strict controls over chemical content of brain (selective - > keeps good stuff in and bad stuff out)
• proper functioning of neurons depends on regulation of chemisty of intra and extra-cellular fluids
• also protects brain from infection since it lacks the body’s immune-system protection and cells can’t regenerate
• barrier consists mainly of specialized capillaries (smallest blood vessels)
• only small uncharged and some fat soluble molecules can passively cross the barrier, others (glucose = primary nutrient) must be actively transported (energetic, protein-mediated)
• glia cells also help create the barrier
• NOTE: the barrier is weaker in the Medulla, allowing some toxins to pass which can trigger vomiting

Question 13

Barrier consists mainly of specialized capillaries

Answer 13

• in most of the body, gaps between endothelial cells of capillary walls allow passage of chemicals in/out
• in the brain, endothelial cells tightly joined (no gaps) = Blood-Brain Barrier

Question 14

fat-solubles

Answer 14

include thiamin (vitamin B1, required for glucose use), nicotine, heroin, cannabinol

Question 15

brain = less than ____ of body weight but requires ____of continuous blood supply!

Answer 15

2%

20%

Question 16

arteries vs. veins

Answer 16

incoming vs. outgoing