Ch. 5 The Central Nervous System

Question 1

What are the three protections of the CNS

Answer 1

Cranium, meninges, CSF

Question 2

Explain what meninges are

Answer 2

• Inside the bones, covering surface of brain + spinal chord= three layers of connective tissue forming membranes = meninges

Question 3

What are the three layers of the meninges

Answer 3

o Outer layer= tough, fibrous, sticks closely to bones on skull, but on inside of vertebral canal= not close fitting
o Middle= loose mesh of fibres
o Inner= delicate, contains blood vessels and sticks closely to surface of brain + spinal chord

Question 4

What are the three functions of the CSF

Answer 4

• 3 functions (protect, support, transport)
  o acts as shock absorber
  o also supports brain (brain suspended + floats in CSF)
  o CSF= formed in blood> circulates CNS (taking nutrients to cells of brain + sp.c. and carries away wastes)> re enters blood capillaries

Question 5

What is the General Function of the cerebral cortex

Answer 5

Higher order functions

Question 6

What is the General Function of the corpus callosum

Answer 6

communication b/w two hemispheres

Question 7

What is the General Function of the cerebellum

Answer 7

coordination of fine movements and maintenance of balance and posture

Question 8

What is the General Function of the hypothalams

Answer 8

homeostasis

Question 9

What is the General Function of the medulla oblongata

Answer 9

(under influence of hypo) regulates heart, breathing, diameter of blood vessels

Question 10

What is the General Function of the spinal chord

Answer 10

pathway for communication b/w effector and brain

reflexes

Question 11

What is the layers of the cerebrum

Answer 11

o Cerebral Cortex (outer grey matter)
o White matter
o Inner basal ganglia (grey matter)

Question 12

What are convolutions, sulci and fissures

Answer 12

• Contains convolutions (gyri; singular gyrus) > increase SA
• Separated by either:
  o Sulci= shallow down folds
  o Fissures= deep down folds

Question 13

What is the corpus colosseum composed of

Answer 13

o White matter consisting of a large bundle of transverse fibres

Question 14

What is the white matter between grey layers of the cerebrum composed of

Answer 14

o Composed of bundles of nerve fibres (tracts, nerves outside CNS)= with myelin sheath,

Question 15

What are the three types of tracts in the cns

Answer 15

1. Tracts that connect various areas of the cortex within same hemisphere
2. Tracts that carry impulses b/w left/right
3. Tracts that connect cortex to other parts of brain/spinal chord

Question 16

What are the three functional areas of the cerebrum

Answer 16

o Sensory areas- receive + process/interpret nerve impulses from receptors
o Motor areas- send impulses/controls for muscular movement (i.e. voluntary)
o Association areas- concerned with intellectual and emotional processes, interpret info from the senses and make it useful

Question 17

what is basal ganglia

Answer 17

• Basal ganglia (grey matter in each hemisphere)

o Consists of groups of nerve cell bodies= associated with control of skeletal muscles

Question 18

How does cerebrum control memory

Answer 18

o Association areas involved in memory
o Memories not stored in individual memory cells, they are pathways of nerve cells
o When memory is stored= new links are made b/w neurons, or existing link= modified

Question 19

what are the two areas of the cerebellum

Answer 19

o	Outer (folded part)= grey matter 
o	Inner= white matter, branches to all parts of the cerebellum

Question 20

if damaged occurred in the cerebellum what would be a consequence

Answer 20

• impulses don’t originate from cerebellum // would still move if didn’t have though would be sporadic, uncontrolled

Question 21

What re the three centres of the medulla oblongata

Answer 21

o	Cardiac Centre 
♣	Regulates rate + force of heartbeat
o	Respiratory Centre
♣	Control rate + depth of breathing
o	Vasomotor Centre
♣	Regulates diameter of blood vessels

Question 22

what are reflexes controlled by the medulla oblongata

Answer 22

swallowing, sneezing, coughing, vomiting,

Question 23

what allows the spinal chord to bend

Answer 23

Outermost layer= does not join to bone= space containing fat, connective tissue + blood

Question 24

what is the spinal chord composed of

Answer 24

o	grey (H) (nerve cell bodies + unmyelinated) 
o	white matter (myelinated fibres)