14.3 a reflex arc

Question 1

what is the central nervous system (CNS) made up of?

Answer 1

brain and spinal cord

Question 2

what is the peripheral nervous system (PNS) made up of?

Answer 2

pairs of nerves that originate from either the brain or the spinal cord

Question 3

what is the peripheral nervous system divided into?

Answer 3

• sensory neurones (nervous system)

- motor neurones (nervous system)

Question 4

what is the motor (neurones) nervous system

Answer 4

• voluntary nervous system

- autonomic nervous system

Question 5

what do sensory neurones do?

Answer 5

carry nerve impulses from receptors towards the central nervous system

Question 6

what do motor neurones do?

Answer 6

carry nerve impulses away from the central nervous system to the effectors

Question 7

what is the voluntary nervous system?

Answer 7

carries nerve impulses to body and muscles and is under voluntary (conscious) control

Question 8

what is the autonomic nervous system?

Answer 8

carries nerve impulses to glands, smooth muscle and cardiac muscle and is under involuntary (subconscious) control

Question 9

what is a reflex?

Answer 9

involuntary response to a sensory stimulus

Question 10

what is a reflex arc?

Answer 10

pathway of neurones involved in a reflex

Question 11

what is the order of a reflex arc?

Answer 11

stimulus
receptor
sensory neurone
intermediate neurone
motor neurone
effector
response

Question 12

what is the coordinator also called?

Answer 12

intermediate neurone

Question 13

what do intermediate neurones do?

Answer 13

link sensory neurones to the motor neurones in the spinal cord

Question 14

what is the importance of reflex arcs?

Answer 14

• involuntary-> brain not involved so not overloaded
• protect body from harm-> not a learnt response
• fast-> only 1 or 2 synapses
• rapid -> absence of decision- making process