brain gross structure

Question 1

what is the advantage of having a control centre for the whole body

Answer 1

communication between billions of neurones involved is much faster than if control centres for different functions were distributed around the body

Question 2

meninges

Answer 2

protective membranes

Question 3

cerebrum

Answer 3

• controls voluntary actions e.g. learning, memory, personality, conscious thought
• receives sensory information, interprets in with respect to that stored from previous experience and sends impulse along motor neurone to effectors to produce appropriate response
• coordinates all voluntary responses and some involuntary ones
• highly convoluted to increase SA, capacity for complex activity
• split into left and right hemispheres

Question 4

cerebral cortex

Answer 4

• outer layer of the cerebral hemispheres
• 2-4 mm thick
• sophisticated processes e.g. reasoning, decision making occur in frontal/prefrontal lobe

Question 5

sensory area of brain

Answer 5

• located in both hemispheres
• receives information from receptor cells located in sense organs
• size of sensory area allocated is in proportion to the relative number of receptor cells present in that body part
• information is passed onto other areas of the brain (association areas) to be analysed and acted upon
• impulses go to motor areas

Question 6

motor area of brain

Answer 6

• impulses arrive and motor neurones send them out e.g. move skeletal muscles
• size of motor area allocated is in proportion to the relative number of motor endings in it
• main region which controls movement is primary motor cortex in back of frontal lobe

Question 7

which side of the brain is responsible for which side of the body

Answer 7

• impulses from each side of the body cross
• so left hem receives impulses from right side and vice versa
• e.g. inputs from eye pass to visual area in occipital lobe where impulses from right side of field of vision in each eye are set to visual cortex in left hemisphere and vice versa
• through the integration of these inputs, the brain is able to judge distance and perspective

Question 7

cerebellum

Answer 7

• controls unconscious functions e.g. posture, balance, non-voluntary movement, muscle coordination
• does not initiate movement, but coordinates it
• cerebellum receives information from organs of balance in ears and about tone of muscles and tendons
• then relays this information to areas of cerebral cortex involved in motor control

Question 8

medulla oblongata

Answer 8

• used in autonomic control e.g. controls heart rate and breathing rate
• contains many important regulatory centres of the autonomic nervous system
• control reflex activities e.g. ventilation and heart rate
• controls swallowing, peristalsis, coughing

Question 9

hypothalamus

Answer 9

• regulatory centre for temperature and water balance
• main controlling region for autonomic nervous system
• has 2 centres- one for parasympathetic and sympathetic
• controls complex patterns of behaviour e.g. feeding, sleeping, aggression
• monitors composition of blood plasma e.g. concentration of water and blood glucose so has rich blood supply
• produces hormones as it is an endocrine gland

Question 10

pituitary gland

Answer 10

• stores and releases hormones that regulate many body functions
• found at base of hypothalamus
• approx size of a pea
• controls most glands in body
• divided into anterior and posterior

Question 11

anterior pituitary gland

Answer 11

• front section
• produces 6 hormones- FSH, LH, ACTH, TSH, Growth hormone

Question 12

posterior pituitary gland

Answer 12

• back section
• stores and releases hormones produced by hypothalamus e.g. ADH, oxytocin

Question 13

what happens if cerebellum is damaged

Answer 13

person suffers from jerky and uncoordinated movement