nervous system

Question 1

types and functions of neurones

Answer 1

sensory neurone: transmits nerve impulses from sense organs to the central nervous system
relay neurone: transmits nerve impulses from sensory neurone to motor neurone
motor neurone: transmits nerve impulses from central nervous system to effectors (muscles)

Question 2

pathway of nerve impulses when touching something

Answer 2

receptors in skin stimulated, causing nerve impulses to be produced -> nerve impulses transmitted by sensory neurone to spinal cord -> nerve impulses transmitted across synapse to relay neurone -> nerve impulses transmitted to brain where they are interpreted

Question 3

pathway of nerve impulses in a voluntary action

Answer 3

brain produces nerve impulses -> relay neurone transmits impulses down spinal cord -> nerve impulses transmitted across synapse to motor neurone -> motor neurone transmits nerve impulses to effector to carry out action

Question 4

pathway of nerve impulses in a reflex action

Answer 4

receptors in skin stimulated and nerve impulses produced -> nerve impulses transmitted by sensory neurone to spinal cord -> nerve impulses transmitted across synapse to relay neurone -> nerve impulses transmitted across synapse to motor neurone -> motor neurone transmits nerve impulses to effectors to carry out reflex action

Question 5

nervous pathway when hand touches hot object

Answer 5

1. receptors in skin are stimulated by heat from object and nerve impulses are produced
2. sensory neurone transmits nerve impulses to spinal cord
3. in the spinal cord, nerve impulses are transmitted across a synapse to a relay neurone, then across another to a motor neurone
4. motor neurone transmits nerve impulses from spinal cord to effector
5. effector (bicep muscle) contracts and causes hand to move away

Question 6

what is a reflex arc

Answer 6

the shortest pathway by which nerve impulses travel from a receptor to an effector in a reflex action

Question 7

similarities between endocrine and nervous control

Answer 7

both are a means of coordination within the body
stimulus causes transmission of an impulse to an effector which carries out the response

Question 8

differences between endocrine and hormonal control

Answer 8

1. endocrine control involves hormones as signals while nervous control involves nerve impulses
2. hormones are transported by the blood in endocrine control while nerve impulses are transmitted by neurones in nervous control
3. endocrine control involves slow responses while nervous control involves quick responses
4. responses to endocrine control are always involuntary while responses to nervous control can be voluntary or involuntary
5. endocrine control may affect more than one target organ while nervous control is localised and only affects a particular part of the body