The Skin
The skin is the covering of the whole body both in human and other animals,human skin is usually in two colors i.e. dark and light. The skin is the largest organ in the body, it is not uniformly thick and it’s about 20 square feet.
Appendages of the Skin
The following are said to be the appendages of the skin I.e. things that attaches to the skin;
- Hair follicles with hair
- Nails
- Sweat gland
- Mammary gland
- Sebaceous gland
Types of skin
I can tell you that the skin is divided into four types; I believe you will be thinking about the layers but I am talking about the types not the layers, the types are;
- Dry Skin
- Oily Skin
- Combination Skin
Types of skin
Division of skin
Thick Skin: The thick skin is the type of skin that is found in body with about 5mm thickness, examples are foot skin, the interscapular region and the palm.
Thin Skin: This type of skin is found in other parts of the body except the parts mentioned above, the thinnest part is the eyelids and the penis that has 0.5mm thickness.
Layers of the Skin
As I said earlier that the layers are different from the types, so the following are the layers of the Skin;
a. The Epidermis Layer
b. The Dermis Layer
c. The subcutaneous Layer
The Epidermis Layer: This is the visible and touchable part of the skin. It is the outer layer of the skin and it is formed by stratified epithelial cells. It serves as a protection for the body from environmental havoc. The Epidermis layer can also be divided based on the layer inside it.
Layers of Epidermis
i. Stratum Corneum: This is also called honey layer and it is the outermost part
ii. Stratum Lucidum: This is made up of flattened epithelial cell
iii. Stratum Granulosum: This is a thin layer of two rows of flattened rhomboid cells
iv. Stratum Spinosum: This layer is also called prickle cell layer
v. Stratum Germinativum: This is a thick layer made up of polygonal cells, superficial and columnal or cuboidal epithelial cells.
Functions of Epidermis
a. It creates new skin cells
b. It gives skin its color
c. Protect the body
The Dermis Layer: This is the inner layer of the skin; it is in between the epidermis and the subcutaneous layers of the skin. It is made up of dense and stout collagen fibers, fibroblast and histiocytes. It also contains beds of vascular connective tissues, sweat gland and hair follicles. It is responsible for the wrinkles.
Layers of the dermis
The following are the layers of the dermis;
a. Superficial papillary layer
b. Deep reticular layer
The superficial papillary Layer: This contains blood vessels, lymphatic and nerve fibers. It also have some pigments-containing cells called Chromatofores
The deep reticular layer: it is made up of reticular and elastic fibers which are found around the hair bulbs, sweat gland and sebaceous glands. This layer contains mast cells, nerve ending, lymphatic epidermal appendages and fibroblast.
Functions of dermis
a. Production of sweat
b. Helps in feelings
c. It grows hair
d. Production of oil
The Subcutaneous Layer: This is the bottom layer of the skin, it’s a layer of tissue that lies immediately after the dermis, and it is also called fat layer or the hypodermis
Functions of subcutaneous layer
a. Control of body temperature
b. It attaches the dermis to the bones and muscles
c. Fat storage
SKIN COLOR
The color of the skin depends on two important factors
a. Pigmentation of skin
People have different types of skin color because there are different kind of Melanin produced by Melanocytes in the body through the process called Melanogenesis. Melanin is responsible for the coloration of skin and the Melanocytes that produces it are present mainly in the Stratum Germinativum and the Stratum Spinosum of the epidermis. The increase in melanin content cause the darken of the skin while the deficiency causes Albinism (The medical condition in which there is very light skin, white hair and pink eyes)
See Melanin work
b. Hemoglobin in the blood
Hemoglobin is a part in the blood that carries oxygen through the body, it also contains iron and it also gives blood its red color. The amount and nature of hemoglobin that moves round the cutaneous blood vessels has important features in the color ration of the skin.
Note: Skin becomes
i. Pink, when the blood rushes to the skin due to cutaneous vasodilation
ii. Pale, when hemoglobin content decreases
iii. Dark, when hemoglobin content increases
iv. Bluish, when there is cyanosis
Skin Disorders
- Psoriasis: It’s a medical condition in which there is variety of rashes
- Dandruff: It’s a scaly medical condition of the scalp which may be caused by seborrheic dermatitis,psoriasis etc.
- Warts: This happens when virus infect the skin and causes the skin to grow excessively.
- Melanoma: This is the most dangerous types of skin cancer.
- Herpes: This is caused by the herpes virus which leads to periodic blisters of skin irritation around the lips .
Skin Test
- Skin biopsy: This is done by the removal of a piece of skin and the skin is examined under a microscope to identify the skin condition.
- Skin testing: This is done by adding extracts of common substances such as pollen to the skin
Skin Treatments
- Medicines that can kill bacteria are being administered
- Anti fungal drug medications
- Skin surgery
- Anti viral drugs are used