Chapter 2: Functional Neuroanatomy (Part 2)

Question 1

Brain and spinal cord are surrounded by ________ protective membranes, the ________.

Answer 1

three; meninges

Question 2

Name and define the meninges.

Answer 2

• Dura mater
  
  • most outer layer; made of tough connective tissue that’s important for stabilizing and structural support to the brain
  • located closest to skull
• Pia mater
  
  • innermost layer; made of a very very thin layer that’s important for many small blood vessels and works to protect our CNS with cerebral fluid protection
  • located closest to brain
• Arachnoid mater
  
  • in between layer; made of what looks like cobwebs and filled with cerebral fluid that’s important for protection of the brain, acts like a cushion and many blood vessels nourish the brain
  • located in between dura mater and pia mater

Question 3

The ________ system is a series of chambers in the brain filled with ________ ________.

Answer 3

ventricular; cerebrospinal fluid (CSF)

Question 4

What are the two functions of CSF?

Answer 4

• acts as a shock absorber
• provides an exchange medium between blood & brain

Question 5

What cells produce CSF?

Answer 5

ependymal cells; choroid plexus also contains lots of material to produce more CSF

Question 6

What is the flow of CSF?

Answer 6

1. lateral ventricles: (bilaterally) CSF produced
2. third ventricle: flow into a midline structure
3. fourth ventricle: midline structure

third & fourth ventricle: separated by cerebral aqueduct, an ally way between the ventricles; important because these ventricles provide CSF to the brainstem area

Question 7

Brain vasculature

Answer 7

…

Question 8

Arteries vs Veins

Answer 8

• afferents; delivering oxygenated blood, glucose, & other nutrients to the brain tissue; 1L blood every min for proper function
• efferent, deoxygenated blood, metabolism byproducts & waste from brain and sent back to heart, repair

Question 9

What two main arteries bring blood to the brain?

Answer 9

1. Internal carotid artery
2. Vertebral artery

Question 10

Internal carotid artery

Answer 10

major artery that brings blood to the brain; located on both sides of the neck, internal and external branches
- branch into anterior & middle cerebral arteries
- anterior cerebral artery: blood to most of cerebral hemispheres (not the occipital lobes)
- middle cerebral artery: blood to lateral surfaces of cerebral hemispheres

Question 11

Vertebral artery

Answer 11

supply oxygenated blood to approx 20% of the brain but most of the brain receives blood from the internal carotid artery; located bilaterally
- blood flow to cerebellum, meninges, & brainstem
- vertebral arteries fuse together at the base to form basilar artery
- basilar artery gives rise to posterior cerebral arteries
- blood to ventral-posterior surface of brain & occipital lobe

Question 12

Where do basilar, vertebral & internal carotid arteries combine and intermix blood supply?

Answer 12

Circle of Willis

Question 13

Circle of Willis

Answer 13

ring of arteries, a fail safe where vertebral & carotid arteries mix, it’s a an important protective mechanism system because if one of these arteries gets blocked there will still be the other arteries to supply blood & nutrients

any blockage after the circle of willis destroyed or lost because the arteries break off into capillary beds supporting blood to the whole brain

Question 14

Blood collects in the ________ ________ system and travels through ________ ________ back to the heart.

Answer 14

venous drainage; jugular vein

Question 15

Stroke (cerebrovascular disease)

Answer 15

caused by the rupture or blockage of blood vessels, leading to insufficient blood supply; preventing blood from going where it needs to go
- 85% ischemic stroke

Question 16

Ischemic stroke vs Hemorrhagic stroke

Answer 16

• clots or other debris prevent blood from reaching a region of the brain , causing it to die
• occurs when a rupture in an artery allows blood to leak into the brain

Question 17

Blood Brain Barrier (BBB)

Answer 17

limits passage of substances between blood and brain
- formed by tightly packed capillaries & astrocytes
- higher resistance in brain capillaries restricts passage of large molecules from the blood into brain tissue
- BBB acts like a bouncer

Question 18

Is the BBB continuous throughout the brain?

Answer 18

No, there a few spots that don’t have BBB
ex. area postrema (vomit center)

Question 19

What can pass through the BBB easily and what cannot?

Answer 19

• gas, fat solubles like alcohol, nicotine, & anesthetics
• nutrients need to be transported through special cells or transporters

Question 20

What cells are within the BBB?

Answer 20

astrocytes & endothelial cells