Central Nervous System

Question 1

How is the nervous system divided?

Answer 1

anatomically and functionally, into:

CNS
PNS

Question 2

What does the CNS consist of?

Answer 2

brain

spinal cord

Question 3

What does the PNS consist of?

Answer 3

cranial nerves (from brain)
spinal nerves (from spinal cord)

Question 4

How does the CNS develop?

Answer 4

from a hollow tube, where:

• one end becomes enlarged (rostral)
• one end is non-enlarged (caudal/tail)

Question 5

What happens to the rostral end of the developing hollow tube that forms the CNS?

Answer 5

ultimately becomes the brain

Question 6

What happens to the caudal/tail end of the developing hollow tube that forms the CNS?

Answer 6

remains as spinal cord

Question 7

What are the 3 compartments that the rostral end of the hollow tube divide into?

Answer 7

forebrain
midbrain
hindbrain

Question 8

What does the forebrain. subdivide into?

Answer 8

telencephalon and diencephalon

Question 9

What does the midbrain divide into?

Answer 9

remains as mesencephalon

Question 10

What does the hindbrain become?

Answer 10

metencephalon (pons) and myelencephalon (medulla)

Question 11

What is the cerebellum?

Answer 11

outgrowth from hindbrain that is involved in control of movement

Question 12

Telencephalon

What are the 2 structures involved?

Answer 12

cerebrum

basal ganglia

Question 13

Telencephalon

What is the cerebrum composed of?

Answer 13

2 cerebral hemispheres

Question 14

Telencephalon

What is the cerebrum the site of

Answer 14

site of ‘highest’ level of neuronal processing responsible for motor activity, sensory perception, consciousness, etc.

Question 15

Telencephalon

What is the cerebral cortex?

Answer 15

outer layer of cerebrum composed of grey matter

Question 16

Telencephalon

What is the grey matter of the cerebrum?

Answer 16

neuronal cell bodies, dendrites, synapses

Question 17

Telencephalon

What is the white matter of the cerebrum?

Answer 17

myelinated axons arranged in discrete bundles (tracts), located below cortex

Question 18

Telencephalon

How much volume of the brain does the cerebrum make up?

Answer 18

~85% total brain volume

• after 11 weeks, expanding cerebral hemispheres have overgrown diencephalon

Question 19

Telencephalon

What do basal ganglia do?

Answer 19

involved in movement control

Question 20

Diencephalon

What are the 2 structures that arise?

Answer 20

thalamus

hypothalamus

Question 21

Diencephalon

What does the thalamus do?

Answer 21

important relay station for processing information going to cerebrum

Question 22

Diencephalon

What does the hypothalamus do?

Answer 22

fundamental role in regulation of ‘automatic’ bodily functions

Question 23

Brainstem

What are the 3 structures that make up the brainstem?

Answer 23

midbrain
pons
medulla

Question 24

Brainstem

What are 2 other components in the brainstem?

Answer 24

white matter

nuclei

Question 25

Brainstem What does white matter do?

Answer 25

carry information to or from cortex

Question 26

Brainstem Where is white matter found?

Answer 26

all levels of brainstem contain tracts of white matter

Question 27

Brainstem What are nuclei?

Answer 27

groups of cell bodies

Question 28

Brainstem What do nuclei do?

Answer 28

responsible for function of cranial nerves

Question 29

What is reticular formation?

Answer 29

set of interconnected nuclei located throughout brainstem, forming central core of brainstem

Question 30

What are the 3 main functions of the reticular formation?

Answer 30

ascending: responsible for generation and maintenance of arousal and consciousness descending: responsible for generation and maintenance of muscle tone respiratory and cardiovascular centres: of fundamental importance, located in medulla

Question 31

What are ventricles?

Answer 31

series of chambers developed from a cavity of the primitive tube

Question 32

What are the 4 ventricles?

Answer 32

lateral ventricles (2 – left and right) 3rd ventricle 4th ventricle

Question 33

Where are the lateral ventricles (2)?

Answer 33

left and right cerebral hemispheres

Question 34

Where is the 3rd ventricle?

Answer 34

(midline) located in diencephalon, between thalami

Question 35

Where is the 4th ventricle?

Answer 35

located between dorsal surface of pons and overlying cerebellum

Question 36

What is the cerebral aqueduct?

Answer 36

connects 3rd and 4th ventricles

Question 37

What does CSF fill?

Answer 37

ventricles

Question 38

What is CSF produced by?

Answer 38

produced continuously by choroid plexus (specialized tissue)

Question 39

What happens to CSF if there's an obstruction somewhere?

Answer 39

fluid will accumulate upstream to the obstruction – results in hydrocephalus

Question 40

Where does CSF travel?

Answer 40

1. CSF leaves ventricular system via apertures between cerebellum and medulla 2. fluid fills space surrounding entire CNS (brain and spinal cord) – ~90% of CSF volume is in this space

Question 41

What system is CSF apart of?

Answer 41

ventricular system

Question 42

What are the functions of CSF?

Answer 42

- buoyant effect – protects against tendency of various forces (including gravity) to distort brain - excretion of waste (metabolic by-products from neurons and glia) - transport of hormones

Question 43

What are the 3 membranes that cover the outer surface of CNS?

Answer 43

pia mater arachnoid membrane dura mater

Question 44

What is the pia mater?

Answer 44

inner membrane layer – follows indentations of surface

Question 45

What is the arachnoid membrane?

Answer 45

middle membrane layer – fits ‘loosely’ over surface

Question 46

What space does the arachnoid membrane create?

Answer 46

subarachnoid space – space between pia mater and arachnoid membrane

Question 47

Describe CSF in the arachnoid membrane.

Answer 47

- CSF is located beneath | - arachnoid membrane has rich blood supply (veins) – CSF is reabsorbed back into veins at this site

Question 48

What is the dura mater?

Answer 48

outer membrane layer– very thick and tough, with a protective function