What are reflex actions? Give two examples. Explain a reflex arc.
[5 Marks]
[5 Marks]
Reflex actions are quick, sudden, immediate response of the body to a certain stimuli that mostly involves spinal cord and the spinal nerves.
[0.5 Marks]
For example: when our hand touches a very hot electric iron, we move away our hand with a jerk. [0.5 Marks]
Reflex Arc: The path through which nerve signals involved in a reflex action travel is called the reflex arc. The following flowchart shows the flow of the signal in a reflex arc.
[1 Mark]
Receptor → Sensory neuron → Relay neuron → Motor neuron → Effector (muscle)
[0.5 Marks]
The receptor is an organ which comes in contact with the danger zone. The sensory neurons pick signals from the receptor and send them to the relay neuron. The relay neuron is present in the spinal cord. The spinal cord sends signals to the effector via the motor neuron. The effector comes into action and moves the receptor away from the danger. [2.5 Marks]
Reflex actions are quick, sudden, immediate response of the body to a certain stimuli that mostly involves spinal cord and the spinal nerves.
[0.5 Marks]
For example: when our hand touches a very hot electric iron, we move away our hand with a jerk. [0.5 Marks]
Reflex Arc: The path through which nerve signals involved in a reflex action travel is called the reflex arc. The following flowchart shows the flow of the signal in a reflex arc.
[1 Mark]
Receptor → Sensory neuron → Relay neuron → Motor neuron → Effector (muscle)
[0.5 Marks]
The receptor is an organ which comes in contact with the danger zone. The sensory neurons pick signals from the receptor and send them to the relay neuron. The relay neuron is present in the spinal cord. The spinal cord sends signals to the effector via the motor neuron. The effector comes into action and moves the receptor away from the danger. [2.5 Marks]
