The body wall of birds has three regions, Skin, Muscles and Peritoneum.
- The skin is dry. It shows upper stratum corneum, which has flat cornified cells. The feathers cover the body. Dermis shows musculo-fibrous tissue. The muscles help to raise and lower the feathers. It is supplied with blood vessels and nerve fibres.
- Glands are absent in the skin of a bird except preen gland which is located on the upper surface of the tail. Its secretions keep the feathers water proof.
- Muscles: Below the skin Muscles are present. In birds skeletal muscles are well developed. The flight muscles are well developed which help to raise and lower the wing.
- Peritoneum: A thin epithelium called peritoneum will cover the inner surface of the muscles.
- In birds skin sweat glands are absent and hence bird cools itself in hot environment by panting.