In knee jerk reflex,
A functions as receptor organ while
B functions as effector organ, Choose the option which gives the correct answer for the blanks in above statement.

Options

A. A-Patella bone B-Biceps muscles
B. A-Quadriceps femoris muscle B-Hamstring muscle
C. A-Hamstring muscle B-Quadricep femoris muscle
D. A-Patellar tendon B-Quadriceps femoris muscle

Answer

To solve the question regarding the knee jerk reflex, we need to identify the receptor organ and the effector organ involved in this reflex action.

### Step-by-Step Solution:

1. **Understanding the Knee Jerk Reflex**:
- The knee jerk reflex, also known as the patellar reflex, is a simple reflex action that occurs when the patellar tendon is tapped. This causes a sudden extension of the leg.

2. **Identifying the Receptor Organ**:
- In the knee jerk reflex, the receptor organ is the **patellar tendon**. When the tendon is tapped, it stretches, and this stretch is detected by sensory receptors (muscle spindle fibers) located in the tendon.

3. **Identifying the Effector Organ**:
- The effector organ in this reflex is the **quadriceps femoris muscle**. When the sensory receptors detect the stretch, they send signals to the spinal cord, which then activates the quadriceps muscle to contract, resulting in the kicking motion of the leg.

4. **Final Answer**:
- Therefore, in the statement, A (receptor organ) is **patellar tendon**, and B (effector organ) is **quadriceps femoris muscle**.

### Summary:
- The correct option for the blanks in the statement is:
- A: Patellar tendon
- B: Quadriceps femoris muscle