Chapter 5 - The Centeral Nervous System

Question 1

What are the parts of the CNS?

Answer 1

• brain

- spinal cord

Question 2

What are the protective structures of the CNS?

Answer 2

• bones
• meninges
• cerebrospinal fluid

Question 3

What are the protective structures of the brain?

Answer 3

• cranium: part of the skull that houses the brain
• meninges: 3 layers of connective tissue that cover the brain
• cerebrospinal fluid: clear watery fluid, found between inner and middle meninges

Question 4

What is the function of cerebrospinal fluid?

Answer 4

• acts as a shock absorber

- circulates the CNS, carries nutrients to cells of the brain and spinal cord

Question 5

What are the characteristics of the cerebrum?

Answer 5

• largest part of the brain

- three layers: cerebral cortex - grey matter, below cortex - white matter, basal ganglia - deep inside - grey matter

Question 6

Why is the cerebral cortex folded?

Answer 6

To increase surface area

Question 7

What % of all neurons in the CNS are found in the cerebral cortex?

Answer 7

70%

Question 8

What are gyri?

Answer 8

Convolutions in the cerebral cortex

Question 9

What are sulci?

Answer 9

Shallow folds

Question 10

What are fissures?

Answer 10

Deep down folds

Question 11

What is the longitudinal fissure?

Answer 11

• deepest fissure, along the length of the brain

- seperate the cerebrum into right and left hemispheres

Question 12

What are the lobes of the brain?

Answer 12

• frontal
• temporal
• occipital
• parietal

Question 13

What are tracts?

Answer 13

• found in white matter under cerebral cortex

- bundles of myelinated nerve fibres (in PNS called nerves)

Question 14

What are the types of tracts?

Answer 14

1. Tracts that connect areas of the cortex within the same hemisphere
2. Tracts that carry impulses between the left and right hemispheres
3. Tracts that connect the cortex with other parts of the brain (ie. cerebellum)

Question 15

What are the functions of the cerebrum?

Answer 15

• thinking
• reasoning
• learning
• memory
• intelligence
• conscious awareness of surroundings
• high-order functions

Question 16

What are the types of functional areas in the cerebrum?

Answer 16

1. Sensory - interprets impulses from receptors
2. Motor - controls muscular movement
3. Association - concerned with emotional and intellectual processses

Question 17

What is the corpus callosum?

Answer 17

• wife band of nerve fibres that lie underneath the cerebrum at the base of the longitudinal fissure

Question 18

What is the function of the corpus callosum?

Answer 18

• contains nerve fibres that cross from one cerebral hemisphere to the other and allow the two sides of the cerebrum to communicate with each other

Question 19

What are the characteristics of the cerebellum?

Answer 19

• lies under the rear part of the cerebrum

- 2nd largest part of the brain

Question 20

What is the structure of the cerebellum?

Answer 20

• surface is folded into parallel ridges
• outer grey matter
• inner white matter (branched)

Question 21

What is the function of the cerebellum?

Answer 21

• coordination of fine contractions of muscles resulting in smooth movements and the maintenance of balance and posture
• takes place below conscious level

Question 22

What is the function of the hypothalamus?

Answer 22

• controls body activities concerned with homeostasis: heart rate, body temperature, movement of food through alimentary canal, food/water intake (appetite and thirst), secretion on releasing/inhibiting factors

Question 23

What is the medulla oblongata?

Answer 23

A continuation of the spinal cord, 3cm in length

Question 24

What is the function of the medulla oblongata?

Answer 24

• under the influence of the hypothalamus, regulates the heart, breathing and diameter of blood vessels.

Question 25

What centres does the medulla oblongata contain?

Answer 25

• cardiac centre: regulates rate and force of the heartbeat
• respiratory centres: control rate and depth of breathing
• vasometer centre: regulates the diameter of blood vessels

Question 26

What other centres are found in the medulla oblongata?

Answer 26

• centres that regulate the reflexes of swallowing, sneezing, coughing and vomiting

Question 27

What are the characteristics of the spinal cord?

Answer 27

• cylindrical structure
• 44cm in length
• extends from Dora men magnum to second lumbar vertebrae

Question 28

What are the functions of the spinal cord?

Answer 28

1. Carries pulses up to the brain and motor impulses down from the brain
2. Intergrates certain automatic, protective reflexes

Question 29

What is the structure of the spinal cord?

Answer 29

• inner: grey matter
• H shaped
• central canal: at cross bar of H, runs the length of the spinal cord and contains cerebrospinal fluid
• outer matter: white matter
• arranged into tracts

Question 30

What are the two different types of tracts in the white matter of the spinal cord?

Answer 30

• ascending: sensory axons that carry impulses upward

- descending: motor axons that carry impulses downwards, away from the brain

Question 31

What are the protective structure of the spinal cord?

Answer 31

• vertebral canal: bone that encloses the spinal cord, formed by openings in the vertebrae
• meninges: three layers of connective tissue, outer layer not joined to bone; instead there is a space containing fat, connective tissues and blood vessels that acts as padding and allows the spine to bend
• cerebrospinal fluid: found in central canal and between inner and middle layers of meninges, functions: protection, support, transport.