I. STRUCTURE OF THE SKIN: The skin has three layers:
1.The Epidermis On The Outside:
- The epidermis is striated squamous epithelium. The main cells of the epidermis are the keratinocytes, which synthesis e the protein keratin. And it is made from layers of cells with a basal layer, which is always forming new cells through cells division. The new cells gradually move towards the surface, which takes 1-2 months. As they move up they gradually die(we can't see this cells die by eyes), become flattened and develop keratin.
- Moving from the lower layers upwards to the surface the four layers of the epidermis are:
- Stratum basale( basal or germinativum cell layer): is the only layer but it is very especially because of ability to produce all another layer. Making up a small proportion of the basal cell population is the pigment( melanin ) producing melanoytes. The number and size of the pigment( melanin) will determine the color of your skin color, eyes color....
- Stratum spinosum( spinous or prickle cell layer): is the thickness layer, as basal cells reproduce and mature, they move towards the outer layer of skin, initially forming the stratum spinosum.
- Stratum granulosum(granular cell layer): Continuing their transition to the surface the cells continue to flatten, lose their nuclei and their cytoplasm appears granular at this level.
- Stratum corneum(horny layer): Is the outermost layer include of the dead cells are destroyed, it si very easy to peel
- In addition, the stratum lucidum is a thin layer of translucent in thick epidermis.
- Together, the stratum spinosum and stratum granulosum are sometime referred to as the Malphigian layer.
- The elastic fibres make your skin resilient.
- Connective tissue packs and bind the other structure in the skin.
- Capillaries with a lot of tiny blood feed the skin.
- Muscle fibres.
- Sensory cells make the feeling of pain, cold, heat,pressure...
- Nerve fibres.
- Sweat glands which open under skin and onto the surface as pores.
- Sebaceous glands produce oil to help waterproof the skin.
- If the sebaceous glands are strong : is oil skin.
- If the sebaceous glands are weak : is dry skin.
- If they are regularly: is normal skin.
- If it are strong at your forehead, nose, chin and weak at 2 cheek : is a combination skin.
- The fat layer under skin protect the skin from the effect of mechanical thermal insulation, energy reserves.
No comments:
Post a Comment