Anatomy And Physiology 2 (Che 231) Integumentary System PDF

ANATOMY AND PHYSIOLOGY 2 (CHE 231) INTEGUMENTARY SYSTEM Presented by Mr. Zubbey Onoruoiza  Introduction The integumentary system consists of the skin, its accessory structures such as hair and sweat glands, and the subcutaneous tissue below the s...

ANATOMY AND PHYSIOLOGY 2 (CHE 231) INTEGUMENTARY SYSTEM Presented by Mr. Zubbey Onoruoiza  Introduction The integumentary system consists of the skin, its accessory structures such as hair and sweat glands, and the subcutaneous tissue below the skin. It is the largest organ of the body. It separates the internal environment of the body from the external environment and prevents the entry of many harmful substances.  Layers of the Skin The two major layers of the skin are The Epidermis (outer layer) and The Dermis (inner layer).  Epidermis The epidermis is a keratinized epithelium—that is, it has a tough, horny superficial layer that provides a protective outer surface overlying its regenerative and pigmented deep or basal layer. The epidermis has no blood vessels or lymphatics. The avascular epidermis is nourished by the underlying vascularized dermis. The skin is also supplied with afferent nerve endings that are sensitive to touch, irritation (pain), and temperature. Most nerve terminals are in the dermis, but a few penetrate the epidermis.  Epidermis The epidermis can be divided into four (or five layers) depending on its location in the body. Skin that has four layers of cells is referred to as thin skin. From superficial to deep, these layers are the stratum corneum, stratum granulosum, stratum spinosum and stratum basale. Thick skin is found only on the palms of the hands and the soles of the feet. It has a fifth layer, called the stratum lucidum, located between the stratum corneum and the stratum granulosum.  Epidermis and Dermis Stratum corneum Stratum basale  Dermis The dermis has two layers -Papillary layer which support and nourishes the Stratum basale epidermis. Papillary -Reticular layer layer which has many accessory structures. Connective tissue of the dermis has both Reticular collagen and elastin fibers. layer Strength and elasticity are two characteristics of the dermis.  Dermis The epidermis has no capillaries of its own, and the lower, living cells depend on the blood supply in the dermis for oxygen and nutrients. Within the dermis are the accessory skin structures: Hair and nail follicles, Sensory receptors Several glands (including sweat glands). Some of these project through the epidermis to the skin surface, but their active portions are in the dermis.  Function of the skin The skin protects the body from environmental effects, such as abrasions, fluid loss, harmful substances, ultraviolet radiation, and invading microorganisms. The skin have sensory (somatic) nerve endings for sensation of pain, temperature and touch. Heat regulation is another function of the skin, the sweat produced by sweat glands is important in the maintenance of normal body temperature.  Function of the skin The skin control evaporation of body water by presence of keratin on the outer epidermal layer. Keratin is relatively water proof and it prevents most evaporation of body water. The living portion of the epidermis also produces and stores vitamin D (sunshine vitamin). The skin has a role in the excretion of excess Sodium chloride which is also lost in sweat, as well as small amounts of urea (a nitrogenous waste product of amino acid metabolism).  Function of the skin Absorption of the skin is limited but substances that can be absorbed include: some drugs, in transdermal patches, e.g nicotine as an aid to stopping smoking and some toxic chemicals, mercury which is toxic can also be absorbed from the skin surface. Keratin also prevents the entry of water into the skin, making the skin water resistant. The skin also provides aesthetic and beautifies the human body.  Assignment Draw and label the skin clearly showing it’s accessory structures. Explain the structure of the skin and the function of each layer of the skin. How does bleaching creams make the skin light?  Pigmentation of the skin Melanocytes are found in the lower epidermis (stratum basale). Melanocytes produce a protein pigment called melanin. In people with dark skin, the melanocytes continuously produce large amounts of melanin. The melanocytes of light skinned people produce less melanin.  Pigmentation of the skin Melanin production is increased by exposure of the skin to ultraviolet rays, which are part of sunlight and are damaging to living cells. As more melanin is produced, it is taken in by the epidermal cells as they are pushed toward the surface. This gives the skin a darker color, which prevents further exposure of the living stratum basale to ultraviolet rays.  Skin care and hygiene Personal hygiene involves keeping all parts of the external body clean and healthy. It is important for maintaining both physical and mental health. Failure to keep up a standard hygiene can have many implications such as increased risk of getting an infection or illness.  Skin care and hygiene Regular routine of personal care, washing and grooming of the body: Skin The skin can be groomed by bathing or showering regularly using soap. By wearing clean clothes and maintaining a healthy diet. By staying out of the sun or using sunscreen when going out.  Skin care and hygiene Teeth The teeth can be groomed by brushing twice a day for 2 minutes and flossing daily, using a fluoride toothpaste By replacing the toothbrush every 2-3 months, limiting sugar intake and seeing a dentist every 6 months. Hair The hair is groomed by washing regularly with shampoo and rinsing thoroughly with clear water to remove all soap, By brushing and combing daily and avoid sharing combs and brushes.  Skin care and hygiene Hands The hands should be washed daily with soap and water, and the nails should be cut short and kept clean. Feet The feet should be washed at least once a day and it should be kept clean and dry, socks should be changed regularly.  Disease conditions of the skin Viral infections Warts Warts is caused by Human papilloma virus (HPV) and are spread by direct contact, e.g. from another lesion, or another infected individual. There is proliferation of the epidermis and development of a small firm growth. Common sites are the hands, the face and soles of the feet.  Disease conditions of the skin Bacterial infections Impetigo This is commonly caused by Staphylococcus aureus. Superficial pustules develop, usually round the nose and mouth. It is spread by direct contact and affects mainly children and immunosuppressed individuals.  Disease conditions of the skin Fungal infections Ringworm These are superficial infections of the skin. In ringworm there is an outward spreading ring of inflammation. It most commonly affects the scalp and is found in cattle from which infection is spread to people.  Disease conditions of the skin Fungal infections Tinea pedis (athlete's foot) This commonly occurs in people whose feet have become very sweaty while confined within tight-fitting shoes. It affects the area between the toes. Both infections are spread by direct contact.  Disease conditions of the skin Non-infective inflammatory conditions Eczema This is an allergic reaction that manifests as dry, itchy patches of skin that resemble rashes. It may be accompanied by swelling of the skin, flaking, and in severe cases, bleeding.  Disease conditions of the skin Non-infective inflammatory conditions Albinism Albinism is a genetic disorder that affects (completely or partially) the coloring of skin, hair, and eyes. The defect is primarily due to the inability of melanocytes to produce melanin. Individuals with albinism tend to appear white or very pale due to the lack of melanin in their skin and hair.  Disease conditions of the skin Non-infective inflammatory conditions Vitiligo In vitiligo the melanocytes in certain areas lose their ability to produce melanin, possibly due to an autoimmune reaction. This leads to a loss of color in patches. Neither albinism nor vitiligo directly affects the lifespan of an individual.  Disease conditions of the skin Skin cancer Anyone can get skin cancer, and the most important factor is exposure to sunlight. Light-skinned people are more susceptible to the effects of ultraviolet (UV) rays, which may trigger mutations in living epidermal cells. Squamous cell carcinoma and basal cell carcinoma are the most common forms of skin cancer. The lesions are visible as changes in the normal appearance of the skin, and a biopsy is used to confirm the diagnosis.  Disease conditions of the skin Malignant melanoma Malignant melanoma is a more serious form of skin cancer, which begins in melanocytes. Any change in a pigmented spot or mole should prompt a person to see a doctor. Melanoma is serious not because of its growth in the skin, but because it may metastasize very rapidly to the lungs, liver, or other vital organ.  Burns First-Degree Burn In first degree burn only the superficial epidermis is burned, and is painful but not blistered. Light colored skin will appear red due to localized vasodilation in the damaged area. Vasodilation is part of the inflammatory response that brings more blood to the injured site.  Burns Second-Degree Burn The deeper layers of the epidermis are affected in second degree burns. Another aspect of inflammation is that damaged cells release histamine, which makes capillaries more permeable. More plasma leaves these capillaries and becomes tissue fluid, which collects at the burn site, creating blisters. The burned skin is often very painful.  Burns Third-Degree Burn This results in the entire epidermis being charred or burnt away, and the burn may extend into the dermis or subcutaneous tissue. Extensive third-degree burns are potentially life threatening because of the loss of the stratum corneum of the epidermis. Without this natural barrier, living tissue is exposed to the environment and is susceptible to infection and dehydration.  The End Quick Recap Any Questions? Test  Sources Moore Clinically Oriented Anatomy. Anatomy and Physiology in Health and Illness. Anatomy and Physiology; Opensax College. Essentials of Anatomy and Physiology.