Choose the correct statement:

Options

A. Receptors do not produce graded potential
B. Nociceptors respond to changes in pressure
C. Meissner's corpuscles are thermoreceptors
D. Photoreceptors of human eye are depolarized during darkness and become hyperpolarized in response to the light stimulus

Answer

To solve the question "Choose the correct statement," we will analyze each of the provided options step by step.

### Step 1: Analyze the First Option
**Statement:** Receptors do not produce graded potential.

- **Explanation:** This statement is incorrect. Receptors are specialized cells that respond to stimuli and generate graded potentials. When a receptor detects a stimulus, it causes a change in the membrane potential, leading to either depolarization or hyperpolarization. Therefore, receptors do produce graded potentials.

### Step 2: Analyze the Second Option
**Statement:** Nociceptors respond to the changes in pressure.

- **Explanation:** This statement is also incorrect. Nociceptors are sensory receptors that specifically respond to painful stimuli, such as injury or damage to tissues. They do not primarily respond to pressure changes. Instead, mechanoreceptors are the ones that respond to pressure.

### Step 3: Analyze the Third Option
**Statement:** Meissner corpuscles are thermoreceptors.

- **Explanation:** This statement is incorrect as well. Meissner corpuscles are mechanoreceptors that respond to light touch and vibration. They are not thermoreceptors, which are specialized for detecting temperature changes.

### Step 4: Analyze the Fourth Option
**Statement:** The photoreceptors of the human eye are depolarized during darkness and hyperpolarized during light stimulus.

- **Explanation:** This statement is correct. In darkness, photoreceptors (rods and cones) maintain a depolarized state with a membrane potential of approximately -40 mV. When exposed to light, they undergo hyperpolarization, changing the membrane potential to about -65 mV. This change in potential is crucial for the transmission of visual signals to the brain.

### Conclusion
After analyzing all the options, the correct statement is:
**The photoreceptors of the human eye are depolarized during darkness and hyperpolarized during light stimulus.**