1. The Brain
The human brain is the site of the major coordination in the nervous system.

2. The Brain
Cerebrum
Hypothalamus
Pituitary gland
Cerebellum
Medulla

3. Areas of the brain
The brain is composed of Cerebral Hemispheres, Cerebellum and Medulla
Medulla
Cerebral
Hemispheres
Cerebellum

4. medulla
Controls autonomic activities including heart rate, and ventilation rate
Impulse transmitted from medulla via sympathetic or parasympathetic branch of automatic nervous system
Medulla
Cerebral
Hemispheres
Cerebellum

5. cerebellum Co-ordination of body movement, balance and posture
Cerebral
Hemispheres
Cerebellum

6. cerebrum/cerebral hemispheres
Highly Folded and so has a large SA.
Patients with injuries to specific parts of the brain can be studied to see how their functions are altered.
Cerebral
Hemispheres
Cerebellum
Medulla

7. cerebrum/cerebral hemispheres
Different parts of the brain can be stimulated electrically to see which muscles in the body respond
Conversely different parts of the body can be stimulated to see which parts of the brain show electrical activity.
More recently MRI (magnetic resonance imaging) has been used in brain study

9. Areas of the cerebrum

10. The Areas can be split into 3 groups
Sensory Areas
Motor Areas
Association Areas

11. Motor
Association
Sensory
Sensory area for impulses from eyes

12. cerebrum/cerebral hemispheres
Sensory areas of the cerebral hemispheres receive impulses from sense organs and transmit them to the association areas
The association areas of the cerebral hemispheres receive impulses - interpret them in the light of similar past experiences and transmit impulses to motor areas
The motor areas transmit impulses to the effectors
The size of the sensory and motor areas is related to the number of receptors in that area
The left and right cerebral hemispheres control the opposite sides of the body

13. Mapping of the sensory & motor areas to the body

14. Sensory & Motor Maps
The maps show that regions of the body with many sensory (or motor) neurones have corresponding large areas of the cerebrum linked to them.
So for example the lips occupy a larger region of the sensory cortex than the shoulder, because there are more sensory neurones in the lips.

15. Association Areas
Are used to compare sensory input with previous experiences, and make decisions
These areas are involved in speech, understanding and memory retrieval
The frontal lobes are large in humans and it is thought that they responsible for higher functions like abstract thought, personality & emotion.

16. Speech The left side of the brain
Patients with speech problems gave 1st clues about how the brain controls language
1981 Dr Paul Broca described a patient who could only say the word “tan”.
When the patient died Broca examined the brain and found damage to the left cerebral hemisphere
This part of the brain is now know as Broca’s area

17. Broca’s Area
Broca’s area

18. Wernicke’s Area
In 1967 Karl Wernicke noticed damage to another region of the cortex.
Werniche’s area is connected to Broca’s area by a bundle of nerve fibres.
If this was damaged the patient can understand language but cannot repeat words.
So Werniche’s area is concerned with understanding language. Broca’s area is concerned with controlling the muscles that produce speech

19. Wernicke’s Area
Wernicke’s area

20. Visual Processing
The visual sensory area is at the back of the brain & receives sensory input from the optic nerves
The 2 hemispheres see slightly different images from the opposite of the visual field, and differences can be used to judge distance

21. Optic Chiasma

22. Summary Sensory areas – receive input from receptors
Motor areas – Origin of impulses which bring about voluntary movements
These receive/transmit impulses from the opposite side of the body
Association areas – interpret sensory information in the light of experience

23. A close shave