ANP LO3

Briefly explain why sunburned skin peels rather than being shed as a powder.

Sun burned skin peels because the skins cells are held together by desmosomes which branch through and onto other skin cells keeping them together.

Explain why warm, dry climates feel cooler than warm, humid climates, even though the temperatures may be the same.

Sweat evaporation is more difficult, meaning that less heat is dissipated from the body (vapor pressure inhibits evaporation).

What are the two types of sweat glands?

Exocrine Glands of the Skin Skin houses many types of exocrine glands Two most common types. Sweat glands and Sebaceous glands. Sweat glands have Two groups, Merocrine and Apocrine. Sebaceous glands are Holocrine glands which Produce oily secretion known as sebum

What is the effect of sunlight on skin color? Why?

Exposure to sunlight causes keratinocytes to secrete chemicals that stimulate melanocytes. Prolonged exposure causes melanin buildup to help protect the DNA (nucleus) of skin cells from UV radiation by absorbing rays and dissipating as heat.

Merkel cells

Tactile cells, also called Merkel cells, are few in number and found scattered among the cells within the stratum basale. Tactile cells are sensitive to touch and, when compressed, they release chemicals that stimulate sensory nerve endings, providing information about objects touching the skin

Why is a subcutaneous injection with a hypodermic needle a useful method of administering drugs?.

Subcutaneous tissue is vascular tissue. Drugs can enter bloodstream to be distributed throughout the body.

Keratinocytes

are the most abundant cell type in the epidermis and are found throughout all epidermal strata. The stratum basale is dominated by large keratinocyte stem cells, which divide to generate new cells that replace dead keratinocytes shed from the surface. Their name is derived from their synthesis of keratin, a protein that strengthens the epidermis considerably.The keratins found in epidermal cells of the skin are called cytokeratins. Their structure in these cells gives skin its strength and makes the epidermis almost waterproof.

What is acne and how is it formed?

Acne occurs when glands (called sebaceous glands) in the follicles of the skin become overactive. These glands produce sebum, an oily substance that helps to stop the skin drying out. Someone with acne produces too much sebum, which forms a plug with dead skin cells and blocks the follicle.

What is alopecia?

Alopecia areata is a type of hair loss that occurs when your immune system mistakenly attacks hair follicles , which is where hair growth begins. The damage to the follicle is usually not permanent.

What is the ABCD rule?

Asymmetry. One half doesn't match the appearance of the other half. • Border irregularity. The edges are ragged, notched, or blurred. • Color. The color (pigmentation) is not uniform. Shades of tan, brown, and black are present. Dashes of red, white, and blue add to a mottled appearance. • Diameter. The size of the mole is greater than 1/4 inch (6 mm), about the size of a pencil eraser. Any growth of a mole should be evaluated. • Evolution. There is a change in the size, shape, symptoms (such as itching or tenderness), surface (especially bleeding), or color of a mole.

Why is regional infection or inflammation of the skin usually very painful?

Because the Merkel (tactile) cells are present at the epidermal/dermal junction, and each has a nerve ending associated with it; i.e. there are many cells to function as pain receptors.

Carotene

Carotene is yellowy-orange in color and is a powerful antioxidant that helps protect skin cells from oxidative damage. It is transformed in the body into vitamin A, which is essential for vision and good skin health. .

What are ceruminous glands, and what do they produce?

Ceruminous glands are simple, coiled, tubular glands made up of an inner secretory layer of cells and an outer myoepithelial layer of cells. They are classed as apocrine glands. The glands drain into larger ducts, which then drain into the guard hairs that reside in the external auditory canal.

Hemoglobin

Hemoglobin is a molecule in the blood that carries oxygen and, by doing so, lends the skin a reddish-pink color. Where the hemoglobin is not picking up enough oxygen from the lungs and carrying it around the body, the skin can appear blueish, sallow, or grey.

Normal color from hemoglobin, melanin, carotene

Hemoglobin= Gives blood vessels in dermis a reddish tint. Melanin = stored in melanocytes - In black, brown, tan, yellow-brown shades. Carotene - Yellow-orange pigment that accumulates in Subcutaneous fat, Keratinocytes of stratum corneum, Converted to vitamin A by body.

Male pattern baldness continued

It is caused by a combination of genetic and hormonal influences. The relevant gene for male pattern baldness has two alleles, one for uniform hair growth and one for baldness. The baldness allele is dominant in males and is expressed only in the presence of a high level of testosterone, which causes the terminal hair of the scalp to be replaced by thinner vellus, beginning on the top of the head and later at the sides.

What is the cleavage line, and what is its significance?

Langer lines of skin tension, or sometimes called cleavage lines, are topological lines drawn on a map of the human body. They correspond to the natural orientation of collagen fibers in the dermis, and are generally parallel to the orientation of the underlying muscle fibers.

What causes male-pattern baldness?

Male pattern baldness is related to your genes and male sex hormones. It usually follows a pattern of receding hairline and hair thinning on the crown, and is caused by hormones and genetic predisposition. Thinning of the hair, called alopecia can occur in both sexes, usually as a result of aging. In diffuse hair loss, a condition that is both dramatic and distressing, hair is shed from all parts of the scalp.

Melanin

Melanin is the main factor influencing skin color and, the vast array of skin tones are due to the amount of this pigment that is produced by these cells. Melanin protects the body's cells from UV damage, sun exposure will usually cause the melanocytes to produce more pigment than usual.

Mammary glands

Modified apocrine sweat glands of breast - Only function in pregnant and lactating females - Produce milk

In a condition known as sunstroke, the victim appears flushed, the skin is warm and dry, and the body temperature rises dramatically. Explain these observations based on what you know concerning the role of the skin in thermoregulation.

The body is dehydrated so sweat is no longer being produced. Flushed skin would be due to blood being pumped to surface and dilation of blood vessels in an attempt to release heat. Body temp rises because sweat is not evaporating and carrying away heat.

What factors contribute to skin color?

The color of the skin is determined by the concentrations of three main pigments: melanin, carotene and hemoglobin. These are found in the dermis and combine to produce the pigmentation of all surface tissues including the skin, mucous membranes, and even the eyes.

What type of tissue is the dermis?

The dermis is composed of a papillary layer and a reticular layer. The reticular layer of the dermis is made up of dense irregular connective tissue. The hypodermis is a layer of loose connective tissue.

What are the layers (strata) of the epidermis?

The epithelium of the integument is called the epidermis. It is a keratinized, stratified squamous epithelium. Layers from deep to superficial 1. Stratum basale 2. Stratum spinosum 3. Stratum granulosum 4. Stratum lucidum 5. Stratum corneum - 1st three layers composed of living keratinocytes - Corneum and lucidum composed of dead cells

What are the 3 forms of skin cancer?

The most serious is melanoma. Like all body tissues our skin is made up of cells: basal cells, squamous cells and melanocytes. The different types of skin cancer are named for the skin cell where the cancer develops: basal cell carcinoma, squamous cell carcinoma and melanoma.

What layer of skin gives rise to fingernails?

The nails, hair, and exocrine glands of the skin all are derived from the epidermal epithelium. Both nails and hairs are composed primarily of dead, keratinized epithelial cells. Nails are scalelike modifications of the stratum corneum layer of the epidermis that form on the dorsal edges of the fingers and toes.

Many medications can be administered transdermally by applying patches that contain the medication to the surface of the skin. These patches can be attached anywhere on the skin except the palms of the hands and the soles of the feet. Why?

The palms and soles have more eccrine sweat glands, which would cause the patch to not stick there well, and would also make absorption more difficult.

Describe the rule of nines in burn victims.

The severity of a burn injury is measured not only by the degree of the burn, but also by the age of the patient, the general size of the burn, and the location of the burn. For example, a burn on the face may require more extensive treatment than a similar burn on an extremity. The rule of nines is used to estimate surface area of a burn. Simply put, most (but not all) major body areas approximately account for some factor of 9% of the total body surface area. In adults, the anterior and posterior parts of the head and neck count 9% of the total body surface area, each upper limb counts 9%, each lower limb and gluteal region counts 18%, the anterior trunk counts 18%, the posterior trunk counts 18%, and the perineum is 1%. Burns are considered very severe or critical if one of the following criteria is met: 1. Over 25% of the body has second-degree burns. 2. Over 10% of the body has third-degree burns. 3. Third-degree burns are present on the hands, feet, face, or perineum.

An 80-year-old grandmother sets her thermostat at 26oC (80oF) and wears a sweater on balmy spring days. When asked why, the grandmother says she is cold. Can you give one possible cause for her feeling cold?

The subcutaneous fat layer of the hypodermisis gone in an 80-year-old, which makes it more difficult for her body to retain heat.

What is the function of melanin in keratinocytes?

Transfer pigment granules (melanosomes) into keratinocytes.

Dermis

Two layers = Papillary layer and deeper reticular layer. Papillary layer of the dermis - Superficial region, Areolar connective tissue. Reticular layer of the dermis - Deeper, major portion of dermis - Dense irregular connective tissue.

Why are you advised to avoid exercise in a steam room, particularly if you have a heart condition?

When external temperature is lower than body temperature, skin's surface looses heat and cools body. Skin's blood vessels constrict in cool weather and when exercising to allow more blood to reach other areas. A steam room is humid, meaning that sweat will not have a cooling effect, so overheating may occur. Every degree increase means the heart beats faster, which causes the heart to need more blood. A steam room is also hot, compounding the potential for overheating by not constricting blood vessels, decreasing blood flow to the heart and making the heart pump blood to the skin to be cooled by evaporation as well. These things combined means that the heart is working extra hard compared to regular working out.

How do sunscreens protect skin?

contain materials that absorb or block UVA and UVB rays. SPF is a number determined experimentally by exposing subjects to a light spectrum. The amount of light that induces redness in sunscreen-protected skin, divided by the amount of light that induces redness in unprotected skin, equals the SPF.

What is sunless tanner?

create a tanned skin without UV light exposure. Effective ones contain dihydroxyacetone (DHA) as their active ingredient. Sunless tanners do not affect melanin production. Instead, when applied to the epidermis, DHA interacts with the amino acids in the cells to produce a darkened, brownish color.

What are the two major components of the integumentary system?

cutaneous membrane and the accessory structures. The cutaneous membrane has two parts: the superficial epidermis and the deeper dermis. The accessory structures include hair follicles, exocrine glands and nails.

List the functions of the integumentary system.

functions to retain body fluids, protect against disease, eliminate waste products, and regulate body temperature. Protection, Prevention of water loss/gain. Vitamin D3 (cholecalciferol). Secretion & Absorption. Immune function Epidermal dendritic cells. Temperature regulation. Sensory Reception

Melanocytes

have long, branching processes and are scattered among the keratinocytes of the stratum basale. They produce and store the pigment melanin in response to ultraviolet light exposure. Their cytoplasmic processes transfer melanin pigment within melanosomes to the keratinocytes within the basal layer and sometimes in more superficial layers. This pigment (which includes the colors black, brown, tan, or yellow- brown) accumulates around the nucleus of the keratinocyte and shields the nuclear DNA from ultraviolet radiation. The darker tones of the skin result from melanin produced by the melanocytes. Thus, "tanning" is the result of the melanocytes attempting to block UV light from causing mutations in the DNA of your skin cells!

Exocrine Glands of the Skin Other integumentary glands

• Ceruminous glands - Modified apocrine sweat glands - Located only in external ear canal - Secretions of waterproof earwax, cerumen o Traps foreign material o Lubricates acoustic meatus and eardrum