Structure and function of the brain

Gross structure

  • Cerebrum

    • Controls voluntary actions

    • Learning, memory, personality, conscious thought

  • Cerebellum

    • Controls unconscious functions

    • Posture, balance, non-voluntary movement

  • Medulla oblongata

    • Autonomic control

    • Heart rate and breathing rate

  • Hypothalamus

    • Regulatory centre for temperature and water balance

  • Pituitary gland

    • Stores and releases hormones

    • Regulate many body functions

Different images of brain

  • Photos of the brain

    • Taken during autopsies

    • Position of lesion caused by accident tumour or stroke

      • Linked to observed changes in patients behaviour or capabilities

  • MRI

    • Used to investigate structure of brain

    • fMRI developed

      • Allows brain study during activity

    • Active areas identified by increased blood flow

  • CT

    • Series of X-rays

    • Create 3D images of inside of body

Cerebrum

  • Receives sensory information and interprets it

  • Sends impulses along motor neurones to effectors

    • Produce appropriate response

  • Responsible for coordinating body’s voluntary responses

  • Highly convoluted

    • Increases surface area

    • Increases capacity for complex activity

  • Split into left and right halves

    • Each hemisphere controls one half of body

    • Discrete areas perform specific functions

  • Outer layer is cerebral cortex

    • 2-4 mm thick

    • Reasoning and decision making occur in frontal and prefrontal lobe

  • Each sensory area within hemispheres receives information

    • From receptor cells located in sense organs

  • Size of sensory area allocated

    • Proportional to relative number of receptor cells present

  • Information passed to other areas

    • Association areas

    • Analysed and acted upon

  • Impulses come into motor areas

    • Motor neurones send out impulses

  • Primary motor cortex mainly controls movement

    • Located at back of frontal lobe

  • Base of brain

    • Impulses from each side of body cross

    • Left hemisphere receives impulses from right-hand side of body

  • Impulses from right side of field of vision

    • Sent to visual cortex in left hemisphere

    • Integration of inputs means brain can judge distance and perspective

Cerebellum

  • Controls muscular movement, posture and balance

  • Only coordinates movement

  • Area is damaged

    • Jerky and uncoordinated movement

  • Receives information from organs of balance in ears

    • Relays information to cerebral cortex

    • Areas involved in motor control

Medulla oblongata

  • Contains important regulatory centres of autonomic nervous system

  • Control reflex activities

    • Such as ventilation and heart rate

  • Controls swallowing, peristalsis and coughing

Hypothalamus

  • Controlling region for autonomic nervous system

  • Two centres

    • One parasympathetic

    • One sympathetic

  • Controls complex patterns of behaviour

    • Feeding, sleeping, aggression

  • Monitoring composition of blood plasma

    • Concentration of water and blood glucose

    • Has rich blood supply

  • Producing hormones

    • Endocrine gland

Pituitary gland

  • Anterior pituitary

    • Front section

    • Produces six hormones

    • Such as FSH

      • Involved in reproduction and growth hormones

  • Posterior pituitary

    • Back section

    • Stores and releases hormones

    • Produced by hypothalamus

    • Such as ADH

      • Involved in urine production