UNIT 2: (2.2a) Nervous Control

Question 1

what is stimuli?

Answer 1

internal and external changes

Question 2

what does the nervous system consist of?

Answer 2

• brain
• spinal cord
• neurons

Question 3

what does the central nervous system consist of?

Answer 3

• brain

- spinal cord

Question 4

what role do neurons play in our nervous system?

Answer 4

connect the nervous system to all parts of our body. ensure information flows to and from CNS

Question 5

why is information flow essential?

Answer 5

in multicellular organisms cells do not work independently and internal communication is required for survival of a multicellular organism

Question 6

what are neurons?

Answer 6

nerve cells which carry information/ messages along neurons as electrical impulses

Question 7

what are sensory neurons?

Answer 7

pass information/messages in the form of electrical impulses from receptors in sense organs to the CNS

Question 8

what are inter neurons?

Answer 8

operate within the CNS

Question 9

what are motor neurons?

Answer 9

pass information/messages in the form of electrical impulses from the CNS to muscles or glands ( effectors) enabling a response to occur

Question 10

how are messages sent between neurons?

Answer 10

• tiny gap between neurons called a synapse.
• messages in the form of electrical impulses are transferred between neurons by chemicals at synapses
• chemical diffuses between the gap and makes the next neuron transmit an electrical impulse

Question 11

what is the first stage in a response to stimuli?

Answer 11

receptors in our sense organs detect changes in the environment (stimuli)

Question 12

what is the second stage in a response to stimuli?

Answer 12

an electrical impulse is then sent to the CNS via sensory neuron

Question 13

what is the third stage ina response to stimuli?

Answer 13

information arrives at the CNS and is processed

Question 14

what is the fourth stage in a response to stimuli?

Answer 14

if the body needs to perform a physical activity the CNS sends a message to a muscle or a gland via motor neuron

Question 15

what is the fifth stage ina response to stimuli?

Answer 15

the motor neuron then makes the effector respond e.g muscle may contract or a gland releases a hormone

Question 16

what is a reflex action?

Answer 16

rapid, involuntary response that protects the body from harm

Question 17

what is the first stage in the reflex action?

Answer 17

receptors in the skin detect pain

Question 18

what is the second stage in the reflex action?

Answer 18

the pain acts as a stimulus for the reflex action

Question 19

what is the third stage in the reflex action?

Answer 19

an impulse travels from the receptor along the sensory neuron to the spinal cord

Question 20

what is the fourth stage in the reflex action?

Answer 20

an inter neuron connects the sensory neuron to the motor neuron (reflex arc)

Question 21

what is the fifth stage in the reflex action?

Answer 21

an impulse leaves the spinal cord in the motor neuron and travels to the muscle

Question 22

what is the sixth stage in the reflex action?

Answer 22

the muscle responds by contracting and the hand is removed from danger

Question 23

what are examples of a reflex arc?

Answer 23

• blinking
• pupil of the eye dilating in response to no light
• knee jerk reaction

Question 24

why are reflexes faster than normal response?

Answer 24

the brain is ‘by-passed’ as no conscious decision is required

Question 25

what are the parts of the brain?

Answer 25

• cerebrum
• cerebellum
• medulla

Question 26

what is the function of the cerebrum?

Answer 26

controls conscious thoughts, thinking, emotion and intelligence

Question 27

what is the function of the medulla?

Answer 27

controls unconscious activities like heartbeat, breathing

Question 28

what is the function of the cerebellum?

Answer 28

controls muscle coordination and balance