Comparative Anatomy ZOO 420 Zoology Department Dr Elsayed

Comparative Anatomy - ZOO 420 Zoology Department Dr. Elsayed Younis 2(1+1)

The skin of Birds 1 - Epidermis : stratified squamous epithelium rest on a basement membrane. Basal layer known as germinative or malpighian layer while the most outer layer is horny ( called stratum corneum). 2 - Dermis : built up of a connective tissue differentiated into two distinct layers:

B- The inner one known as spongy layer and formed of areolar connective tissue 3 - Subcutaneous : consists of loose connective tissue Skin derivatives 1 - Soft structures : - Uropygial gland (preen gland): produces a fatty secretion ( oil ) uses to preen the feathers - Chromatophores : contain pigments responsible

2 - Hard structures : - feathers : - cover the body except legs, feet, beak and wattle - scales : - cover the skin of lower legs and feet - Keratinized structure : - such as the bill, claws Types of feathers : - Contour feathers : - cover the body ( including the quill feathers of the wings and tail. - Filoplumes feathers : - very thin, hair-like lie at the bases of the

- plumules feathers ( down feathers) : - situated below the contour feathers and used as insulator to conserve body heat.

The skin of Mammals 1 - Epidermis : stratified squamous epithelium rest on a basement membrane. Basal layer known as germinative or malpighian layer while the most outer layer is horny (called stratum corneum). 2 - Dermis : built up of a dense areolar connective tissue

Skin derivatives 1 - Soft structures : - Sebaceous glands : - small simple alveolar glands produce a fatty secretion for hair feeding. - Sweat glands : - simple coiled tubular glands open on the surface of the body through a long winding duct. - Melanophores : contain melanin pigments which responsible for the color of the skin. 2 - Hard structures : - Hair ( is distinguishing character of