Divisions, blood supply, meninges, ventricular & CSF

Question 1

Divisions of nervous system and what they are:

Answer 1

CNS - brain and spinal cord
PNS - is comprised of the cranial/spinal nerves and peripheral ganglia
PNS nerves project to target organs and to muscles (efferent)
These nerves also carry sensory information to the brain (afferent)

Question 2

Blood supply

Answer 2

• Brain receives 20% of blood
• Brain continuously receives 20%
• Brain cannot store glucose and requires oxygen to extract glucose (why continuous blood)

Question 3

Two supplies of blood to the brain

Answer 3

/carotid and vertebral artery…get to the base of the brain, they fuse. All are bilateral

Question 4

Meninges are: incl. names of layers (DAPS!)

Answer 4

tough protective membrane surrounding brain and spinal cord. 
Dura mater
Arachnoid
Pia mater
Subarachnoid

Question 5

Dura mater

Answer 5

outer, thicker and tougher

Question 6

Arachnoid

Answer 6

middle layer

Question 7

Pia mater

Answer 7

inner, soft - contains smaller surface blood vessels

Question 8

subarachnoid

Answer 8

space between arachnoid and pia. Contains cerebrospinal fluid,

Question 9

Ventricular system and cerebrospinal fluid

Answer 9

1. brain is soft, jelly like and delicate; it weighs 1400 g or ~ 3 lbs. Therefore requires protection from shock and trauma
2. brain floats in CSF which reduces weight to ~ 80 g or ~ 3 ozs. and helps protect it from shock

Question 10

Lateral Ventricles

Answer 10

(Biggest) There are two C-shaped cavities called the lateral ventricles.

Question 11

What is CSF produced by?

Answer 11

Choroid plexus

Question 12

The interventricular foramina (of Monro)

Answer 12

(stem above Bird head, like horns) The interventricular foramina (or foramina of Monro) are channels that connect the paired lateral ventricles with the third ventricle at the midline of the brain. As channels, they allow cerebrospinal fluid (CSF) produced in the lateral ventricles to reach the third ventricle and then the rest of the brain’s ventricular system. They also contain choroid plexus, a specialized CSF-producing structure, that is continuous with that of the lateral and third ventricles, and which is also present in the fourth ventricle.

Question 13

Third ventricle

Answer 13

Bird head

Question 14

Cerebral aqueduct

Answer 14

Bird head’s neck

Question 15

Fourth ventricle

Answer 15

directly under bird head’s neck

Question 16

Choroid plexus

Answer 16

continuously extracts csf from blood. Resembles blood plasma. CSF half life is 3 hrs.

Question 17

CFS flows through…

Answer 17

ventricles to 4th to subarachnoid space around brain and spinal cord to superior aspect of brain where it drains into superior sagittal sinus and into veinous system