Brain

Unit 3

Behaviour, Populations and Environment

Learning Outcomes

• To learn about the structure of the brain

• To learn about the convoluted nature of the cerebrum

• To learn about the location of the discrete areas of the brain and their functions

• To relate the size of the discrete areas with the function they carry out

Evolution of the Brain

Brain Structure

Brain Structure

• Plasticity - Brain is flexible. If injured, the functions of the damaged part can be taken by unaffected parts.

• Sensory/ Motor areas - Brain receives information along sensory neurones from sensory receptors in eyes, ears, skin etc. It then sends out information along motor neurones to muscles or glands.

Cerebrum

• Convoluted (folded) which increases number of cell bodies

• 2 halves called cerebral hemispheres

• Controls conscientious thought, voluntary actions, determines personality etc

Areas of Cerebrum

Motor Homunculus

• Imaginary human whose body parts have been drawn in proportion to their mobility and fine motor control

• The more motor control needed, the larger the motor area required

Corpus Callosum

• Mass of fibres which separates cerebral hemispheres

• Transfers information from 1 hemisphere to the other

Cerebellum

• Attached to underside of brain

• Unconscious fine control of voluntary muscle movement and balance

Medulla Oblongata

• Connects brain to spinal cord

• Unconscious co-ordination of basic functions – breathing, heart rate, digestion, reflex actions

Medulla oblongata

EEG

• Electroencephalogram• records brain’s electrical

activities

Split-brain studies

• when a person’s corpus callosum has been cut

• exchange of information between cerebral hemispheres doesn’t occur

Brain Injuries

• Studies for brain injuries include:

• Phineas Gage – frontal lobe determines personality

• a man with visual agnosia mistook his wife for a hat

• soldiers with shrapnel wounds• people with brain lesions• Stroke sufferers

The Facts you need to know

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“in recent human evolutionary history ….”

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“the cerebral hemispheres are ….”