Brain

Question 1

Describe the makeup of the cerebrum

Answer 1

> Divided into 2 hemispheres by longitudinal fissure
At base of longitudinal fissure= corpus callosum
Separated into Grey Matter & White Matter

Question 2

Describe grey matter of brain

Answer 2

where cell bodies lie = non-myelinated
- outer layer of cerebrum = cerebral cortex
- Includes Basal ganglia = group of nuclei spread deep in white matter, involved in motor selection + habit learning (link with thalamus to co-ordinate movement)
> Basal ganglia
- corpus striatum (caudate nucleus, putamen, global pallidus)
- Subthalamic nuclei
- Substantia nigra (commonly affected by parkinson’s)

Question 3

Describe white matter of the brain

Answer 3

• Myelinated axons
• association fibres connect areas within hemispheres
• Corpus Callosum - connects two hemispheres (allows co-ordination of body)
• Internal capsule

Question 4

Describe the frontal lobe

Answer 4

front of brain involved in
1. control of behaviour, personality + emotion
2. memory
3.speech via broca’s area (in left hemisphere: translates thought to speech and produces motor commands for speech)
4. Movement planning + execution
> premotor area - initiation + planning movement
> primary motor cortex - initiates + controls movement
> homunculus - what is controlled by where

Damage to frontal lobe:
- apraxia - struggle to initiate/plan movement
- expressive dysphasia: can’t convert thought > speech
(only if brocas area affected = left side)
- Personality/ behaviour changes

Question 5

Describe the Parietal lobe

Answer 5

middle of brain involved in:

1. Interpretation of sensory input - somatosensory cortex
2. Body awareness
3. Spatial awareness

Damage to parietal lobe
- difficulty perceiving sensory info:
> no sensation/ altered or hypersensation

Question 6

Describe the Temporal lobe

Answer 6

Side of brain involved in:

1. Interpretation of speech
   - Primary auditory area - interprets sound via pitch/rhythm
   - Wernicke’s area - determines what sound is (music/words etc.) and what it means (words>thoughts)
   - memory of sounds + what they mean

Damage to temporal lobe
- affects the interpretation of sound - receptive dysphasia

Question 7

Describe the occipital lobe

Answer 7

Very back of brain involved in:

1. Interpretation of visual input
   - intensity of light/darkness of objects
   - shape + movement of objects
   - colour
   - memory of past visual experiences - evaluation + recognition

Damage to Occipital lobe:
- affects visual interpretation

Question 8

Describe the Brainstem

Answer 8

Involved with:

• unconscious control
• connects with internal capsule via basal ganglia

Consists of:

1. Midbrain
2. Pons
3. Medulla
   - pathways cross here so right brain=left body
   - houses important control centres: respiratory/ cardiac/ vasomotor/ swallowing/ gastric secretion/ sweating/ vestibular nuclei (balance)
   - houses cranial nerves (*7=facial ,10 = vagus)

Question 9

Describe the Diencephalon

Answer 9

Consists of
> Thalamus - between cortex + midbrain
- principle sensory relay system (all sensory info synapses here - then feeds to sensory cortex in parietal)
- interprets some basic sensations
> Hypothalamus - at base of brain near pituitary gland
- regulates homeostasis via influence of Autonomic system and pituitary gland

Question 10

Describe the limbic system

Answer 10

- Underside of cerebrum (bottom of frontal lobes + inner section of temporal lobes) 
> controls emotion
> Memory 
Consists of 
1. Cingulate gyrus (medial side - near corpus callosum)
- links smells + sights with memory
- regulates aggression
- emotional response to pain
2. Hippocampus (deep in temporal lobe)
- memories of people, places, events
3. Amygdala (near hippocampus - almond shape)
- emotions especially anger
4. mamillary bodies

Question 11

Describe the Cerebellum

Answer 11

> works with autonomic response (works closely with pons)
interacts with motor areas to produce smooth, co-ordinated movement with balance
Connected via 3 peduncles (stalks)
- superior - midbrain
- middle - pons
- inferior - medulla

Question 12

Describe what might happen if a stroke affected

1. Frontal lobe
2. Parietal lobe
3. Temporal lobe
4. Occipital lobe
5. Brainstem
6. Thalamus/hypothalamus
7. Limbic system
8. Cerebellum

Answer 12

Stroke would affect:

1. Behaviour/ motor control + speech
2. Sensory deficit
3. Speech + hearing
4. Sight
5. Sensation, motor control, respiratory + cardiac systems
6. Autonomic nervous system
7. Emotions and memory
8. Co-ordination + balance

• Remember that paths cross so stroke in left side will usually affect right side of body