Tanning, skin cancer

Tanning, skin cancer

The topmost layer of our skin is the epidermis, which contains melanocytes.

Biology

Keywords

skin, tanning, skin cancer, disease, melanocyte, melanoma, birthmark, suntan lotion, defence, mutagenic, epidermis, keratinised epithelium, epithelial tissue, dermatologist, metastasis, human, biology

Scenes

Skin

  • epidermis - Its two main layers are the outer keratinous layer (stratum corneum) and the living epidermis. The bottom layer of the living epidermis consists of stem cells which divide continuosly and create new epithelial cells. Older epithelial cells are pushed towards the surface by the new ones; meanwhile they undergo apoptosis (programmed cell death) and keratin protein accumulates in them. The dead epithelial cells filled with keratin form the keratinous layer. It has a protective function. Its thickness varies depending on the location in the body. The epidermis does not contain blood vessels; it receives nutrients from the blood vessels of the dermis through diffusion. It does not contain nerve endings, except for free nerve endings that detect pain.
  • dermis - It consists mainly of loose connective tissue and contains both receptors and blood vessels. These blood vessels also provide nutrients for the epidermis indirectly, through diffusion. Ridges increase the surface area between the dermis and epidermis, thereby strengthening the junction between them and increasing the exchange of nutrients between these two layers.
  • hypodermis - It consists mainly of fatty tissue, which plays an important role in protecting the body against mechanical effects and cold temperature, as well as in storing nutrients and fat-soluble vitamins (A,D,E and K).
  • blood vessel - There are blood vessels in the dermis and the hypodermis, but not in the epidermis. The epidermis receives nutrients through diffusion.
  • nerve - The skin is rich in nerve endings, which play an important role in the senses of touch, temperature and pain.
  • sweat gland - It plays an important role in thermoregulation. These glands help to remove large amounts of water from the body. Since the heat capacity of water is high, perspiration (that is, the removal of warm water) reduces the temperature of the body. This effect is further strengthened by the cooling effect of evaporation.
  • sebaceous gland - It opens to the hair follicle. Its oily secretion provides protection for the skin. Sebaceous glands may get clogged and inflamed, which causes pimples on the skin.
  • arrector pili muscle - Hair erector muscle: its contraction causes the hair to ‘stand on end’. In animals with fur, this results in the thickening of the fur, which, in turn, results in better insulation and makes the animal appear larger and more intimidating for rivals. Body hair in humans has become vestigial over the course of evolution, but the arrector pili muscle reflex has not disappeared.
  • hair bulb - The division of its cells causes the hair to grow.
  • hair - It serves the thermal insulation and protection of the body. Body hair in humans has become vestigial over the course of evolution.
  • birthmark (nevus, mole) - In the wider sense, these are sharply circumscribed, chronic lesions of the skin where the colour or the surface is different from that of the surrounding skin. Some of them are present at birth, while others are formed later. In the ordinary sense, only melanocytic nevi are called birthmarks or moles.

Tanning

  • melanocyte - Specialised, pigment-producing cells in the epidermis. The produced pigments are transferred to other epithelial cells in, thereby protecting their DNA from the damaging effects of sunlight. One of the components of sunlight is UV radiation, which damages cellular DNA and therefore causes mutations (mutagenic effect).
  • melanosome - Membrane vesicles containing a pigment called melanin.
  • keratinocyte - Epithelial cell of the skin.

Birthmark

  • birthmark - In the wider sense, these are sharply circumscribed, and chronic lesions of the skin where the colour or the surface is different from that of the surrounding skin. Some of them are present at birth, while others are formed later. In the ordinary sense, only melanocytic nevi are called birthmarks or moles.
  • melanocyte - Specialised, pigment-producing cells in the epidermis. The produced pigments are transferred to other epithelial cells in, thereby protecting their DNA from the damaging effects of sunlight. One of the components of sunlight is UV radiation, which damages cellular DNA and therefore causes mutations (mutagenic effect).
  • keratinocyte - Epithelial cell of the skin.

Melanoma

  • melanocyte
  • DNA
  • thymine - DNA molecules contain 4 types of nucleobases: thymine, adenine, cytosine and guanine. The order of the nucleobases encodes the amino acid sequence of proteins.
  • UV-radiation
  • thymine dimer - UV radiation causes the formation of thymine dimers in the DNA. This, in turn, causes a disturbance in protein synthesis, which increases the risk of cancer.
  • uncontrolled cell division - UV radiation damages cellular DNA, which causes uncontrolled cell division and tumour formation.
  • melanoma - A malignant tumour that develops from melanocytes. It commonly causes metastases. It is treated surgically, but in case the metastases are widespread, chemotherapy, immunotherapy and radiation therapy may also be necessary.

Protect your skin

  • suntan lotion - Suntan lotion prevents UV radiation from reaching the skin, thereby protecting it against the mutagenic, or DNA damaging effect of UV rays. It is highly recommended to use sun lotion when we are exposed to the sun.

Animation

  • melanocyte - Specialised, pigment-producing cells in the epidermis. The produced pigments are transferred to other epithelial cells in, thereby protecting their DNA from the damaging effects of sunlight. One of the components of sunlight is UV radiation, which damages cellular DNA and therefore causes mutations (mutagenic effect).
  • melanosome - Membrane vesicles containing a pigment called melanin.
  • keratinocyte - Epithelial cell of the skin.
  • melanocyte
  • DNA
  • thymine - DNA molecules contain 4 types of nucleobases: thymine, adenine, cytosine and guanine. The order of the nucleobases encodes the amino acid sequence of proteins.
  • UV-radiation
  • thymine dimer - UV radiation causes the formation of thymine dimers in the DNA. This, in turn, causes a disturbance in protein synthesis, which increases the risk of cancer.
  • uncontrolled cell division - UV radiation damages cellular DNA, which causes uncontrolled cell division and tumour formation.
  • melanoma - A malignant tumour that develops from melanocytes. It commonly causes metastases. It is treated surgically, but in case the metastases are widespread, chemotherapy, immunotherapy and radiation therapy may also be necessary.
  • suntan lotion - Suntan lotion prevents UV radiation from reaching the skin, thereby protecting it against the mutagenic, or DNA damaging effect of UV rays. It is highly recommended to use sun lotion when we are exposed to the sun.
  • birthmark - In the wider sense, these are sharply circumscribed, and chronic lesions of the skin where the colour or the surface is different from that of the surrounding skin. Some of them are present at birth, while others are formed later. In the ordinary sense, only melanocytic nevi are called birthmarks or moles.
  • melanocyte - Specialised, pigment-producing cells in the epidermis. The produced pigments are transferred to other epithelial cells in, thereby protecting their DNA from the damaging effects of sunlight. One of the components of sunlight is UV radiation, which damages cellular DNA and therefore causes mutations (mutagenic effect).
  • keratinocyte - Epithelial cell of the skin.

Narration

The topmost layer of our skin is the epidermis, which contains melanocytes. These are specialised, pigment-producing cells.

When the skin is exposed to UV radiation, the production of pigments in melanocytes is increased and the skin darkens – this is how tanning occurs. The pigments produced by melanocytes are transferred to other cells in the skin, thereby protecting their DNA from the damaging effects of sunshine.

UV radiation is one of the components of sunshine. This radiation damages cellular DNA and therefore causes mutations, which may lead to the formation of skin cancer. Skin cancer often results from mutations that take place in melanocytes. UV radiation causes the formation of thymine dimers in the DNA of melanocytes. This causes a disturbance in protein synthesis, which increases the risk of cancer, that is, uncontrolled cell division and the formation of malignant tumours. Tumour cells can be transferred to other parts of the body, including organs, through blood and lymph circulation. These cells can cause the formation of further tumours. This is called metastasis.

When recognised early, skin cancer can be treated successfully in most instances. Therefore, it is very important to have birthmarks and moles checked regularly by a doctor. Melanomas are removed surgically. When not treated early enough, melanomas commonly metastasise, making them one of the most dangerous types of cancer.

In order to prevent skin cancer, it is highly recommended that we should use suntan lotion when we are exposed to sunshine. Suntan lotion prevents UV radiation from reaching the skin, thereby protecting it against the mutagenic, or DNA-damaging, effect of UV rays.

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