The dermis is:
Vascular and innervated
Avascular and innervated
Avascular and not innervated
Vascular but not innervated
The correct answer and explanation is :
Correct Answer: Vascular and Innervated
The dermis is the middle layer of the skin, lying beneath the epidermis and above the hypodermis. It is both vascular (has blood vessels) and innervated (contains nerve endings), which is crucial for its role in maintaining skin function and overall health.
1. Vascularity of the Dermis
The dermis contains an extensive network of blood vessels that provide oxygen and nutrients to both the dermis and the avascular epidermis (which lacks blood vessels). The two primary vascular plexuses in the dermis are:
- Papillary plexus: Located near the epidermis, it supplies nutrients to the upper skin layers.
- Reticular plexus: Found deeper in the dermis, it plays a role in thermoregulation by adjusting blood flow.
These blood vessels also help with temperature regulation, wound healing, and immune responses.
2. Innervation of the Dermis
The dermis is rich in nerve endings that allow for sensations such as touch, pressure, pain, and temperature. Different nerve receptors include:
- Meissner’s corpuscles: Detect light touch.
- Pacinian corpuscles: Detect deep pressure and vibration.
- Ruffini endings: Detect skin stretch.
- Free nerve endings: Detect pain and temperature changes.
3. Why the Other Answers Are Incorrect
- Avascular and innervated: The dermis has blood vessels, so this is incorrect.
- Avascular and not innervated: The dermis is both vascular and innervated.
- Vascular but not innervated: The dermis has nerve endings, so this is incorrect.
Thus, the dermis is both vascular and innervated, making it essential for sensory perception, thermoregulation, and wound healing.