A Reflex Arc Flashcards
What’s the two major divisions of the nervous system
Central nervous system - which is made up of the brain and spinal cord
Peripheral nervous system - which is made up of pairs of nerves that originate from either the brain or the spinal cord
What are the peripheral nervous system divide into?
Sensory neurones - which carry nerve impulses from receptors towards the central nervous system
Motor neurones - which carry nerve impulses away from the central nervous system to effectors
What can the motor system be further divided into
The voluntary system nervous system - which carries nerve impulses to body muscles and it’s under voluntary control
The autonomic nervous system - which carries nerve impulses to glands, smooth muscle and cardiac muscle and is not under voluntary control, that is, it is involuntary
What’s the spinal cord
A column of nervous tissue that run along the back and lies inside the vertebral column for protection
Describe the main stages of a spinal reflex arc
stimulus - heat from object
Receptor - temperature receptors in skin, generate nerve impulses in the sensory neurone
Sensory neurone passes nerve impulses to the spinal cord
Relay neurone - links the sensory neurone to the motor neurone in the spinal cord
Motor neurone - Carries nerve impulses from the spinal cord to a muscle in the upper arm
Effector - muscle in the upper arm, which is stimulated to contract
Response - pulling the hand away from the hot object
Why are reflex actions important
Involuntary - do not rehire the decision making powers of the brain, thus leaving it to carry out more complex responses
Protect the body from harm- don’t have to be learnt
Fast -neurone pathway is short which very few synapses
