Skin - structure and functions

 SKIN

Human skin consists of 2 layers - the epidermis and the dermis. Under the skin there is a subcutaneous tissue (hypodermis).

SOURCE

Epidermis

👉 built with stratified squamous epithelium

👉 protects the body against external factors and water loss

👉 consists of the two layers: stratum corneum and the stratum germinativum

Stratum corneum

👉 it is hardened due to the deposition of keratin

👉 it peels off systematically

Stratum germinativum

👉 is capable of mitotic division and creates new cells 👉 contains melanocytes that produce melanin - a pigment that protects the skin against the harmful effects of UV radiation and gives the skin color

The epidermis produces:

> hair

> nails

> sebaceous glands

> sweat glands

> mammary glands

Dermis

👉 it is made of fibrous connective tissue

👉 it contains protein fibers that give the skin elasticity and resistance to mechanical damage

👉 it contains blood vessels -> can remove waste products and participate in thermoregulation

👉   it contains pain, pressure, touch, heat and cold receptors, that perceive stimuli from outside

👉 here are placed the products of the epidermis

Hypodermis

👉 it is made of adipose tissue

Functions:

👉 protects the body against heat loss (thermal insulation)

👉 protects against mechanical damage

👉 it is the body's energy reserve

What are the functions of the skin?

♥ synthesizes vitamin D3 from a cholesterol derivative under the influence of UVB
♥ receives stimuli from the environment (heat, cold, touch and pressure receptors)
♥ excretes waste products of metabolism - water and urea (through the sweat glands)
♥ protects the body against the harmful effects of external factors and against the loss of water from the body
♥ regulates the body temperature
♥ secretes sebum, sweat, milk (through the sebaceous, sweat and milk glands)