a) What is a reflex action? b) Outline the activities that occur in the body when one touches a hot object.
a) What is a reflex action?
Rapid and automatic; response to a particular stimulus; 2 mks
b) Outline the activities that occur in the body when one touches a hot object.
When the hot object is touched, the pain receptors; in the skin of the finger are stimulated; nerve impulses are initiated and transmitted through the sensory neurone; to the grey matter; of the spinal cord to the brain; for interpretation; the impulses are then transmitted through the relay neurone; via a synapse; the impulses from the relay neurone are transmitted via the motor neurone; through another synapse; to the effector; which are the biceps muscles of the upper arm; making the muscles to contract; straightening the arm; and the arm is withdrawn from the hot object; Max. 18 mks
Rapid and automatic; response to a particular stimulus; 2 mks
b) Outline the activities that occur in the body when one touches a hot object.
When the hot object is touched, the pain receptors; in the skin of the finger are stimulated; nerve impulses are initiated and transmitted through the sensory neurone; to the grey matter; of the spinal cord to the brain; for interpretation; the impulses are then transmitted through the relay neurone; via a synapse; the impulses from the relay neurone are transmitted via the motor neurone; through another synapse; to the effector; which are the biceps muscles of the upper arm; making the muscles to contract; straightening the arm; and the arm is withdrawn from the hot object; Max. 18 mks
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