Question

The outermost layer of the skin is
A. Dermis
B. Hypodermis
C. Hair follicles
D. Epidermis

Answer 1

Hint: The largest organ of the body is skin. It forms the outer covering of a vertebrate's body that forms a protective covering for the body internally & externally. The skin is the largest organ of our body and it keeps refreshing.

Complete Answer:
Skin is the layer that usually covers the body of an animal. It is usually associated with three main functions: protection, regulation, and sensation.
- In mammals, the skin is an organ of the integumentary system made up of multiple layers of ectodermal tissue and gives information to the underlying organs. The skin interfaces with the environment form the first line of defence from pathogens.
- The thickness of the skin also varies from the location on an organism's body. In humans, for example, the skin under the eyes is the thinnest & measures around 0.5 mm thick whereas the skin on the palms and the soles is the thickest skin of the body that measures about 4 mm thick.

Now let us collect information about given options:
- Dermis: The dermis makes the middle layer of the skin. The dermis is made up of the following: Blood & Lymph vessels , Hair follicles Sweat glands & Sebaceous glands, Collagen bundles & Fibroblasts Nerves.
- Hypodermis: It is the deepest and innermost layer of skin and is usually composed of a network of collagen and fat cells. It is used to store the body heat, acts as a shock absorber so protects the body from injury.
- Hair follicles: Hair follicles are present in the dermis that is the middle layer of the skin. It is not present on the outermost layer.
- Epidermis: An outer thin layer of skin is known as epidermis.

Hence the correct answer is option D.

Note: Epidermis is the outermost layer of skin. The uppermost layer of epidermis is known as Stratum Corneum. This layer is composed of keratin and lipids. The cells in this layer usually possess a 2 week life cycle. The cells die in this layer and are replaced by cells of lower epidermis. The cells of the uppermost layer of epidermis are flat, usually dead and are composed of keratin. This layer protects the skin from light, water, heat, bacteria and chemicals. It acts as the primary barrier between the body and the environment. It can also be named as horny layer as cells are tougher like animal horns.