homeostasis - the nervous system

Question 1

what are the two parts which make up the nervous system

Answer 1

• the central nervous system e.g the brain or the spinal chord
• other nerves which run to and from the central nervous system

Question 2

what is sent via neurons

Answer 2

electrical impulses

Question 3

what are effectors

Answer 3

a muscle which normally contracts or a gland which secretes a hormone

Question 4

what does the nervous system allow humans to do

Answer 4

react to their surroundings and co- ordinate their behavior

Question 5

what happens if we were to touch a hot object? - reflex arc

Answer 5

• the stimulus is detected by the receptor (e.g. heat is the stimulus and the skin is the receptor)
• electrical impulses pass from the receptor to the central nervous system via the sensorary neurons
• a chemical is released at the synapse, this diffuses across to a relay neurons in the central nervous system where an electrical impulse is triggered
• the electrical impulse travels across the relay neurons and reaches another synapse
• another chemical is released
• this chemical then triggers an electrical impulse in the motor neuron
• the impulse travels and reaches na effector
• the muscle contracts and removes it away from the heat - the response

Question 6

what is the junction called at the end of a neuron

Answer 6

a synapse

Question 7

what is special about a reflex

Answer 7

there is no decision making by the conscious part of the brain

Question 8

how do reflexes protect us from danger

Answer 8

because they are automatic and rapid