this helps regulate the body heat. When the body needs to give off heat, the blood vessels expand, the blood is placed closer to the outside air. When the body needs to conserve heat, the blood vessels contract slowing that rate of the heat loss.
Epidermal Products Hair Is a substance that grows out of the skin of mammals. The color, texture and the way it grows are determined by heredity and environment. Parts of the Hair Shaft – main hair fiber Follicle – coating that encloses the root hair Erector Muscle – pushes against the oil glands to help lubricate the hair shafts. It also causes the hair to stand when a person is frightened.
Hair follicle: sac-like anatomical structure from which hair grows.Sebaceous gland: gland that secretes sebum, which lubricates the skin and hair.Arrectorpili muscle: muscle that elevates the hair.Root of hair: part of the hair implanted in the dermis.Papilla: part of the hair connected to the conjunctival tissue.Inner root sheath: sheath formed of several layers of cells.Connective tissue sheath: girdle enclosing the epithelial sheath and connecting to the conjunctival tissue.Epidermis: outer layer of the skin.Hair shaft: a filament that grows from the skin.
Kinds of Hair Fur-soft, dense hair (found on cats, rabbits, dogs & leopards) Fleece-thick, wooly hair (found on sheep) Bristle-short, stiff hair (hound on hogs) Quills-sharp, spiny hair (found on porcupines) Importance of Hair: They provide protection, warmth and sensation (common on animals with tactile hairs or whiskers. This type of hair helps feel the way around through narrow or dark places).
are the cutaneous slits into which the lateral margins are embedded.
Is a sharp hooked nails of bird.
Is the horny covering protecting the ends of digits of some animals like horses.
Horns - Are hard projecting appendages growing on heads of some animals like cattle, goat and deer.
Talons - Are claw found especially on a bird of prey. Antler - Is a branch of horns of a male deer or stag.
Diseases and Disorders of the Skin Rash Such as typical measles or chicken pox, can indicate an infection that affects the whole body. Yellow tinge of the skin signals that the liver is not working properly. A rash is a change of the skin which affects its color, appearance or texture. Rashes may cause the skin to change color, itch, become warm, bumpy, dry, cracked or blistered, swell and may be painful.
Diseases and Disorders of the Skin Acne Occurs when a hair follicle becomes blocked, usually by keratin-containing dead cells, preventing sebum from reaching the surface of the skin. The result of this inflammation is a pimple. Acne tends to occur during the teenage years because hormones that increase at puberty both keratin formation and sebum production.
Diseases and Disorders of the Skin Bacterial Infections
Is commonly found in boils, carbuncles, and pimples.
is a skin disease characterize by blue-green pus, are often infected by pseudomonas aeruginosa.
Diseases and Disorders of the Skin Bedsores or Pressure Sores
also known as pressure ulcers or decubitus ulcers, develop in patient who are immobile
(bedridden or continued to a wheelchair).
The primary cure and treatment is to remove the pressure by turning the patient regularly (every two hours is often quoted, though the evidence for this figure is not strong and four hourly turns may be as effective in some patients).
Diseases and Disorders of the Skin Birthmark
A birthmark is a blemish on the skin formed before birth. A little over 1 in 10 babies have a vascular birthmark.
Are congenital disorders of the capillaries in the dermis of the skin.
The exact cause of most birthmarks is unknown, but vascular birthmarks are not hereditary and many people have them.
are more of a problem when they affect the face or when they affect function of any body part.
are a benign overgrowth of blood vessels, or melanocytes, or smooth muscle, or fat, or fibroblast or keratinocytes. They are thought to occur as a result of a localized imbalance in factors controlling the development and migration of skin cells.
these birthmarks may occur anywhere on the body, they are most commonly oval in shape and light brown, or milk coffee, in color. These birthmarks may be present at birth, or appear in early childhood, and do not fade with age.
is a type of melanocytic nevus (or mole) found in infants at birth. Occurring in about 1% of infants in the United States, it is located in the area of the head and neck 15% of the time, but may occur anywhere on the body.
appears as a pink or tanned, flat, irregularly-shaped mark on the knee, back of the neck, and/or the forehead, eyelids and, sometimes, the top lip.
Diseases and Disorders of the Skin Eczema and Hives Eczema
is a red, scaly rash that commonly occurs in body folds such in front of the elbow, behind the knee, and around the groin.
is a form of dermatitis,or inflammation of the epidermis (the outer layer of the skin)
Hives (also called urticaria)
are red, raised, welt like lesions on the skin, often occurring on the face and neck.
Are often triggered by ingestion or inhalation of a substance, such as a medication or food, to which a person is allergic.
may be an indication of a more serious, even life-threatening allergic reaction.
Fungal Infection Ringworm
is fungal infection that affects the keratinized portion of the skin, hair, and nails and produces patchy scaling and an inflammatory response.
several species of fungus cause ringworm in human are described by their location on the body; in the scalp the condition is ringworm, in the feet it is athlete’s foot, and in the groin, it is JOCK ITCH.
Diseases and Disorders of the Skin Ringworm on a human arm.
Diseases and Disorders of the Skin Mole An elevation of the skin that is variable in size and is often pigmented and hairy. It is an aggregation of melanocytes in the epidermis. Most people have 10 – 20 moles which appear in childhood and enlarge until which appear in childhood and enlarge until puberty.
Skin Cancer Any type of cell present in the skin can become cancerous. Skin cancer develops most commonly on sun-exposed areas, such as the face, hands, arms, and legs. The three most common types of skin cancers are: Squamous Cell Carcinoma is a carcinomatous cancer occurring in multiple organs. These include the skin, lips, mouth, esophagus, urinary bladder, prostate, lungs, vagina, and cervix. Basal Cell Carcinoma is the most common type of skin cancer. It rarely metastasizes or kills. However, because it can cause significant destruction and disfigurement, it is still considered malignant by invading surrounding tissues. Malignant Melanoma is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. Diseases and Disorders of the Skin
Diseases and Disorders of the Skin Melanoma. A basal cell carcinoma. Note the pearly appearance and telangiectasia. Squamous Cell Carcinoma of the skin tends to arise from pre-malignant lesions, actinic keratoses; surface is usually scaly and often ulcerates
Diseases and Disorders of the Skin Viral infection