Brain - Structure & Function

Question 1

What is the general structure of the brain?

Answer 1

Cerebrum – controls voluntary actions – learning, memory, personality, conscious though

Cerebellum – controls unconscious function – e.g. posture, balance, involuntary movement

Medulla oblongata – autonomic control – breathing rate, heart rate

Hypothalamus – regulatory centre for temperature & water balance

Pituitary Gland – stores and releases hormones regulating many body functions

Question 2

What is the function of:

Medial longitudinal fissure?

Corpus Callosum?

Answer 2

• Medial longitudinal fissure separates the left and right hemispheres*
• Corpus callosum – large bundle of fibres connecting left and right hemisphere*
• Why?: Integrates the different functions of each hemisphere*

Question 3

What is the structure and function of the cerebrum?

Answer 3

• Coordinates body’s voluntary response
• It then sends impulses to effectors across motor neurone
• It is highly convoluted – increases surface area to hold a capacity for complex activity
• Split into 2 halves, known as cerebral hemispheres
  
  • each hemisphere controls one half of the body and has discrete sections per function, mirrored in each hemisphere

Outer layer of cerebral hemisphere is the cerebral cortex

In the frontal and prefrontal lobes of the cerebral cortex are involved in reasoning and decision making (most sophisticated processes)

Question 4

What is the structure & function of the cerebral cortex?

Answer 4

• Sensory area - receives impulses from sensory neurone
• Motor area - sends impulses to effectors
• Association areas - link information to coordinate a response

Question 5

Are impulses transmitted from one side of the body, to the corresponding hemisphere of the brain?

Answer 5

• At the base of the brain, an impulse from the left side of the body, reaches the right hemisphere, vice versa
• E.g. inputs from the eye go to the visual area in the occipital lobe
  
  • So impulses from the right eye, reach the visual cortex in the left side and vice versa

Question 6

What is the function of the cerebellum?

Answer 6

• Controls muscular movement, body posture and balance – it coordinates movement, it does not initiate it
  
  • If the brain is damaged, someone has jerks and uncoordinated movement
• Cerebellum receives information from organs of balance in the ears and information about muscle tone and tendons

Question 7

What is the function of the medulla oblongata?

Answer 7

• Contains regulatory centres of autonomic nervous system
• E.g. ventilation, heart rate, swallowing, coughing, peristalsis (constriction and relaxation of muscles of intestines etc.)

Question 8

What is the function of the hypothalamus?

Answer 8

• Main region of control for autonomic nervous system
• Receives information from internal receptors
• Has 2 centres – one for sympathetic and one for parasympathetic nervous system
  
  • Controls complex behaviour patterns – feeding, sleeping, behaviour, aggression
  • Monitors blood plasma composition – e.g. water and blood glucose (so the hypothalamus has rich blood supply
  • Produces hormones – it is an endocrine gland

Question 9

What is the structure and function of the pituitary gland?

Answer 9

Found at base of hypothalamus, has 2 sections

• Anterior pituitary gland (front) – produces 6 hormones, e.g. FSH, growth hormones and reproductive
• Posterior pituitary gland – stores and releases hormones produced by hypothalamus. E.g. ADH