Question

The outer layer of skin is called
(a)Dermis
(b)Epidermis
(c)Plasma
(d)Cortex

Answer 1

Hint: The outer layer of the skin is made up of cells that are flat in shape, called squamous cells and the layer provides a waterproof barrier to the body. It also protects the body from infection by various pathogens.

Complete answer:
The epidermis is known as the outermost layer of the skin. There are two layers of the epidermis, the living basal layer, that is next to the dermis, and the external stratum corneum, or horny layer, which is composed of dead, keratin-filled cells. The Basal (at the bottom of the epidermis) cells are present under the squamous cells.

Additional Information: -The epidermis has no blood supply and depends on diffusion from the dermal cells for all its metabolic needs.
-The dead-cell layer of the stratum corneum protects from a water loss that allows the vertebrates to dwell on land.
- Keratin, produced in migrating epidermal cells, forms the basis of nails in our fingers, feathers, and beaks of birds and other epidermal derivatives.
-The epidermis is thickest on the friction surfaces and thinnest over the eyelids, on the lower parts of the abdomen, and around the external genitalia.
-The epidermis consists of a living malpighian layer, in contact with the basement membrane (which is attached to the dermis), and a superficial horny layer of dead cells. The malpighian layer consists of both the stratum basale and the stratum spinosum of the epidermis layer.
So, the correct answer is, ‘Epidermis.’

Note: The epidermal cells, which multiply chiefly at the base in contact with the dermis, gradually ascend to the surface, manufacturing keratin as they go and finally die in the upper part, forming a horny layer.