Why don't you bleed when you cut your nails? Why don't you bleed when a hair is pulled?

Verified step by step guidance

1. Understand that both nails and hair are composed of keratin, a tough, fibrous protein that is not living tissue.
2. Recognize that nails and hair do not contain blood vessels or nerves, which is why cutting or pulling them does not cause bleeding or pain.
3. Identify that the living part of the nail is the nail bed, which is located beneath the nail plate, and the living part of the hair is the hair follicle, located beneath the skin.
4. Note that when you cut your nails or pull a hair, you are only affecting the non-living keratinized part, not the living tissue that contains blood vessels.
5. Conclude that because the non-living parts of nails and hair lack blood supply, they do not bleed when cut or pulled.

Key Concepts

Anatomy of Nails and Hair

Nails and hair are composed of keratin, a tough protein that forms a protective layer. The visible part of nails, known as the nail plate, does not contain blood vessels or nerves, which is why cutting them does not cause bleeding. Similarly, hair follicles are located beneath the skin, and pulling hair primarily affects the hair shaft, which is also devoid of blood supply.

Skin Structure

The skin consists of multiple layers, including the epidermis, dermis, and subcutaneous tissue. The epidermis is the outermost layer and does not contain blood vessels. When nails are cut or hair is pulled, the action typically does not penetrate deep enough to reach the dermis, where blood vessels are located, thus preventing bleeding.

Pain and Sensation

Pain and sensation are primarily mediated by nerve endings located in the dermis and deeper layers of the skin. Since nails and hair do not have nerve endings in their keratinized structures, cutting nails or pulling hair may cause minimal discomfort but does not trigger the pain response associated with injury to the skin or underlying tissues.