Find out the correct sequence of a simple reflex are:

Options

A. Brain-spinal cord -nerves -effector
B. Effector -CNS -sensory nerves -receptor
C. Muscles -spinal cord -brain -receptor
D. Receptor -sensory nerves -CNS -effector

Answer

To find the correct sequence of a simple reflex arc, we need to understand the components involved in the reflex action. A reflex arc is a neural pathway that controls a reflex action. Here’s the step-by-step breakdown of the correct sequence:

### Step-by-Step Solution:

1. **Stimulus**: The process begins when a stimulus is detected by a receptor. This could be anything from touching a hot surface to stepping on a sharp object.

2. **Receptor**: The receptor, which is a specialized sensory organ or cell, receives the stimulus and converts it into an electrical signal.

3. **Sensory Nerves**: The electrical signal is then transmitted through sensory nerves. These nerves carry the signal from the receptor towards the central nervous system (CNS).

4. **Central Nervous System (CNS)**: The signal reaches the central nervous system, which consists of the brain and spinal cord. In the case of a simple reflex, the signal typically goes to the spinal cord.

5. **Interneurons**: Within the spinal cord, interneurons process the information and relay the response signal to the motor neurons.

6. **Motor Nerves**: The motor nerves carry the response signal away from the CNS to the effector.

7. **Effector**: Finally, the signal reaches the effector, which is usually a muscle or gland that carries out the response, such as pulling your hand away from a hot surface.

### Correct Sequence:
The correct sequence of a simple reflex arc is:
**Receptor → Sensory Nerves → Central Nervous System → Motor Nerves → Effector**

### Conclusion:
Thus, the correct answer is option 5: Receptor, then the sensory nerves, after that the central nervous system, and finally the effector.

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