INTEG SYSTEM

• The integumentary system consists of the skin, hair, oil and sweat glands, nails, and sensory receptors.
• The functions of the integumentary system include helping the body maintain its temperature, storing blood, converting inactive vitamin D to its active form, providing sensory information, protecting the body from the external environment, excreting and absorbing substances, and serving as a basis of diagnosis.
• The size of an adult's burn surface area is estimated using the ______________.
• Ultraviolet light exposure is the most common cause of skin cancer, which includes basal cell carcinoma, squamous cell carcinoma, and malignant melanoma.
• Tissue damage can be caused by excessive heat, electricity, radioactivity, or corrosive chemicals that denature the proteins in the skin cells.
• Burns are graded according to their severity, with the most severe being the fourth degree.
• The skin is the largest organ of the body in weight, weighing 4.5–5 kg (10–11 lbs.) in adults, and has varying thickness, with the eyelids being 0.5 mm (0.02 in.), the heels being 4.0 mm (0.16 in.), and most of the body being 1–2 mm (0.04–0.08 in.).
• The skin consists of two major layers: the epidermis, which is the most superficial layer and is composed of epithelial tissue, and the dermis, which is a layer deep to the epidermis and is composed of connective tissue.
• The epidermis is a keratinized stratified squamous epithelium with four major types of cells: melanocytes (90%), which produce melanin, Langerhans cells (8%), which participate in immune responses, Merkel cells (<1%), which are found in the deepest layer of the epidermis and in contact with the "Tactile (Merkel) Disc", and keratinocytes (<1%).
• The dermis is a layer composed of connective tissue and is vascular.
• The subcutaneous (subQ) layer, also known as the accessory skin structures, is located deep to the dermis but is not a layer of the skin and is composed of areolar and adipose tissue.
• Genetic and hormonal influences determine the thickness and distribution of these accessory structures.
• Hair coloring is a process that adds or removes pigment.
• Prior to birth, the lanugo of the eyebrows, eyelashes, and scalp are shed and replaced by long, coarse, heavily pigmented hairs called lanugo hairs.
• These accessory structures are composed of dead, keratinized epidermal cells.
• The hypodermis, also known as the subcutaneous layer, attaches the skin to underlying tissues and organs.
• The lanugo of the rest of the body are replaced by vellus hairs, commonly called “peach fuzz,” which are short, fine, pale hairs that are barely visible to the naked eye.
• Hair color is determined primarily by the amount and type of melanin in its keratinized cells.
• Dark colored hair contains mostly eumelanin, blonde and red hair contain variants of pheomelanin (yellow to red), and gray hair contains only a few melanin granules.
• Accessory structures of the skin are present on most body surfaces except the palms and palmar surfaces of fingers as well as the soles and plantar surfaces of the feet.
• White hair is a sign of aging and is caused by a progressive decline in melanin production.
• Glands are epithelial cells that secrete a substance.
• Hair follicles develop at about 12 weeks after fertilization and usually by the fifth month of development, the follicles produce very fine, nonpigmented, downy hairs called lanugo that cover the body of the fetus.
• The skin contains four types of glands: Simple branched acinar glands connected to hair follicles, modified sweat glands located in the ear canal, more common, distributed throughout most of the body (especially on forehead, palms, and soles), not present in margin of lips, nail beds of fingers toes, glans penis/clitoris, labia majora, or eardrums, and their main function is to regulate body temperature.
• Temporary hair dyes, semipermanent dyes, and permanent hair dyes are available.
• Disorders include excessive excretion of sweat.
• Age-associated changes include wrinkles, dehydration and cracking, sweat production, and loss of subcutaneous fat.
• Permianis develops from mesoderm and derives from mesenchyme.
• Deep wound healing occurs when an injury extends to the dermis and subcutaneous layer and involves four phases: hemostasis, inflammation, proliferation, and maturation.
• Bacteria are active during emotional sweating and sexual activities and do not begin to function until puberty.
• Emotional stress functions soon after birth and is found mainly on the axilla, groin, areolas, bearded regions.
• Clinical connection refers to an abnormally large amount of cerumen in the external auditory canal that can prevent sound waves from reaching the eardrum.
• Contrary to popular belief, foods such as chocolate or fried foods do not cause or worsen acne.
• Aging skin is a skin condition that affects mostly light skinned adults between the ages of 30 and 60 and is characterized by redness, tiny pimples, and noticeable blood vessels, usually in the central area of the face.
• Sweat appears milky or yellowish in color and are odorless.
• Growth of nails and hair slows during the second and third decades of life.
• Skin glands are plates of tightly packed, hard, dead, keratinized epidermal cells that form a clear, solid covering over the dorsal surfaces of the distal portions of the digits.
• Nail wound healing occurs when superficial wounds affect only the epidermis, involve only slight damage to superficial epidermal cells, and are common types of epidermal wounds include abrasions and minor burns.
• Evaporation through sweat glands includes sweat that evaporates from the skin before it is perceived, known as "invisible sweat", and sweat that is excreted in larger amounts and is seen as moisture on skin, known as "visible sweat".
• Acne is an inflammation of sebaceous glands that usually begins at puberty and occurs predominantly in sebaceous follicles that have been colonized by bacteria.