CNS- Brain And Spinal Cord

Question 1

What is the function of the brain?

Answer 1

Where info from the internal/external environment is processed

Question 2

What are the 3 major regions of the brain?

Answer 2

Cerebrum, cerebellum and brain stem

Question 3

What is the function of the cerebrum?

Answer 3

Largest/most developmentally advanced part of the brain

Responsible for several higher function eg higher intellectual function, speech, integration of sensory stimuli of all types and fine control of movement

Question 4

What is the function of the cerebellum?

Answer 4

Second largest area

Responsible for maintaining balance/posture and further control of movement/coordination

Question 5

What is the function of the brain stem?

Answer 5

Responsible for variety of automatic functions eg control of respiration, HR, BP, wakefulness, arousal and attention

Autonomic functions

Divided into medulla, midbrain and pons

Question 6

What is the corpus callosum?

Answer 6

Band of white matter consisting of a bundle of several million nerve fibres/axons

Allows communication between 2 cerebral hemispheres

Question 7

What is the function of the cerebral cortex?

Answer 7

Area of conscious thought and perception

Question 8

What are the 4 lobes of the cerebral cortex?

Answer 8

Frontal, parietal, occipital and temporal lobes

Question 9

What is the function of the frontal lobe?

Answer 9

Personality, emotions, motor, speech, memory and movement

Question 10

What is the function of the parietal lobes?

Answer 10

Auditory association

Interpretation of words and thoughts, olfactory area, and interpretation of smell

Question 11

What is the function of the temporal lobe?

Answer 11

Speech, language, smell, touch, position sense

Interpretation of sensation, spatial awareness and storage of sensory experience

Question 12

What is the function of the occipital lobe?

Answer 12

Sight/visual interpretation

Past visual experience

Question 13

What is the sensory cortex?

Answer 13

Situated in the parietal lobe

Receives and processed sensory info throughout the body

Transmitted here via sensory neurones from sensory organs eg skin, eyes

Question 14

What is the motor cortex?

Answer 14

Located in the frontal lobe

Responsible for planning, control and voluntary movement

Question 15

What is the limbic system?

Answer 15

Complex set of structures lying on both sides of the thalamus just under the cerebellum

Question 16

What makes up the limbic system?

Answer 16

Hypothalamus

Hippocampus

Amygdala

Question 17

What is the function of the limbic system?

Answer 17

Responsible for our emotional life

Formation of memories

Detecting changes in the internal environment

Question 18

What is the function of the amygdala?

Answer 18

Involved in many of our emotions and motivation- related to survival eg fear, anger etc

Question 19

What is the function of the hippocampus?

Answer 19

Involved in conversion of recent memories into long term memory

Question 20

What is the function of the midbrain?

Answer 20

Uppermost part of brain stem

Contains auditory and visual reflex centres

Controls cranial reflex activities eg blinking

Question 21

What is the function of pons?

Answer 21

Meaning bridge- lies between midbrain and medulla oblongata eg medulla

Relays sensory info between the cerebrum and cerebellum

Question 22

What is the function of the medulla oblongata?

Answer 22

Contains respiratory, vasomotor and cardiac centres for control of breathing and cardiovascular function

Many mechanisms for controlling reflex activities eg coughing, gagging, swallowing and vomiting

Question 23

What is the function of the spinal cord?

Answer 23

Links the brain to the rest of the body

Stretches from the medulla oblongata to the level of the 2nd lumbar vertebrae and runs inside the vertebral canal

Question 24

Where are the sensory and motor nerve fibres found?

Answer 24

Sensory nerve fibres- ascending tracts in SC

Motor nerve fibres- descending tracts in SC

Question 25

What 4 factors protect the brain?

Answer 25

1) cranium (skull)
2) meninges (membranes)
3) cerebrospinal fluid
4) blood-brain barrier

Question 26

What is the function of the meninges?

Answer 26

Membranes around CNS providing another layer of protection- surround brain and spinal cord

3 distinct layer:

1) dura mater- outermost layer- thick/strong
2) arachnoid mater- middle layer- thin/transparent membrane
3) pia mater- innermost layer- delicate/follows brain and SC surface

Question 27

What is the blood brain barrier?

Answer 27

Formed by tight junctions of capillaries and astrocytes (type of glial cells)

Numerous projections- Foot processes- encircle capillary and great semi-permeable membrane, separating blood from neurones in the brain

Offers protection from toxic substances

Also difficult to get some drugs into the brain

Question 28

What does the blood brain barrier stop?

Answer 28

1) most chemicals in blood entering brain eg antibiotics
2) proteins
3) NT leaking out into circulation

Question 29

What does the blood brain barrier not stop?

Answer 29

1) oxygen
2) carbon dioxide
3) most anaesthetic agents
4) few water soluble substances eg glucose
5) alcohol
6) urea and creative (crossing much more slowly)

Question 30

What is cerebrospinal fluid?

Answer 30

Clear fluid containing glucose, proteins, lactic acid, urea and WBC

Produced by ependymal cells (type of glial cell) in choroid plexuses of the ventricles in the brain/ canal of the SC

Helps protect brain and SC

Question 31

What are the functions of CSF?

Answer 31

Contributes to intracranial pressure

Provides medium so nutrients and waste products can be exchanged

Supports weight of brain- ‘float’ in the skull