
Respuesta :
Mammals all have hair, but that hair can be very different from one mammal to another or even on the same mammal IS EXPAINED BELOW.
Explanation:
- Medulla in a human is smaller (medullary index of less than one-third); and medulla in animals is very thick (medullary index of one-half or greater). - Cuticle in humans is imbricated; and the cuticle in animals is coronal or spinous.
- Hair (and a coat of hairs, called fur or pelage) is uniquely mammalian. No other creature possesses true hair, and at least some hair is found on all mammals at some time during their lives. Hairs grow out of pits in the skin called follicles.
- The hair cuticle scales in dog is imbricate, smooth, petal and wide-distant, and the medulla is continuous occupying approximately half of the hair shaft; this is different from the vacuolated structure of the hair medulla described by Mukherjee et al.
- The typical mammalian hair consists of the shaft, protruding above the skin, and the root, which is sunk in a pit (follicle) beneath the skin surface. Except for a few growing cells at the base of the root, the hair is dead tissue, composed of keratin and related proteins.