LO3; Chapter 6 Integumentary system

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

Subcutaneous tissue is vascular tissue so drugs can be distributed to enter the blood stream throughout the body.

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

UV sunlight stimulates melanin production which makes skin color appear darker as a result of melanocytes attempting to protect the skin from UV damage

What is sunless tanner?

products used to create a tanned skin color without UV light exposure where only the most superficial epidermis cells are affected and skin color change is temporary.

Describe the rule of nines in burn victims

rules of nines is used to estimate the surface area of a burn. Estimating surface area of a burn is critical for determining an appropriate fluid replacement, the greater the surface area of the burn, the greater volume of fluids that are lost. These fluids must be replaced. Most major body areas account for 9% of the total body area; each upper limb counts 9% each, each lower limb and gluteal region counts 18%, anterior trunk counts 18%, posterior trunk counts 18%, and perineum is 1%.

What is the ABCDE rule?

rules used to asses signs of melanoma where A= asymmetry, B= border, C= color, D= diameter, E= evolving

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

Steam rooms are humid so sweat produced won't have the typical cooling effect so overheating can occur. People with heart conditions should be cautious because this can lead to overworking the heart and decreasing blood flow to the heart by making the heart pump blood to the skin to be cooled instead

What are the layers (strata) of the epidermis? From deep to superficial

Stratum basale, Stratum spinosum, Stratum granulosum, Stratum lucidum, Stratum corneum

What layer of skin gives rise to fingernails?

Epidermal layer

What causes male-pattern baldness?

A combination of genetic and hormonal influences. The gene for it 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 high levels of testosterone.

What is acne and how is it formed?

Acne is the term used to describe plugged sebaceous ducts. Acne can be caused by stimulation of sebaceous glands (e.g. puberty; sex hormones) which makes pores more prone to blockage.

What is alopecia?

Alopecia is an autoimmune disorder where hair follicles are attacked.

What are the 3 forms of skin cancer?

Basal cell carcinoma: most common Squamous cell carcinoma: arises from keratinocytes of stratum spinosum Malignant Melanoma: most deadly type of skin cancer due to aggressive growth and metastasis

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

Because Merkel cells are present at the epidermal junction and have nerve endings that function as pain receptors.

What are ceruminous glands and what do they produce?

Ceruminous glands are modified apocrine sweat glands located only in the ear canal where their secretion forms a waterproof earwax called "cerumen". Cerumen helps to trap foreign objects from reaching the eardrum and helps lubricate the external acoustic meatus and eardrum.

What type of tissue is the dermis?

Connective tissue proper

List the functions of the integumentary system

Covers body and consists of skin and accessory tissues, protection, prevention of water loss/gain, secretion and absorption, sensory reception, etc

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

Desmazones are interlocking structures so it sheds off as a unit rather than breaking off as a powder form.

What factors contribute to skin color?

Hemoglobin- gives blood vessels in the dermis a reddish tint, Melanin- pigment produced and stored in melanocytes and presents black, brown, tan, yellow-brown shades Carotene- yellow/orange pigment that accumulates in sebaceous fat and keratinocytes of stratum corneum; is converted to vitamin A in the body

What is the function of melanin in keratinocytes?

Keratinocytes hold melanin which responds to UV light exposure. Their cytoplasmic processes transfer melanin pigment within melanosomes to the keratinocytes within the basal layer. This pigment accumulates around the nucleus of the keratinocytes and shields the nuclear DNA from UV radiation.

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?

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?

Describe the following cell types: Merkel cells, melanocytes, basal cells, and keratinocytes.

Merkel cells- tactile cells, are few in number and are found scattered among the cells within the stratum basale. Tactile cells are sensitive to touch and when compressed, release chemicals that stimulate sensory nerve endings, providing information about objects touching the skin. 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 UV light exposure. Basal cells- a type of cell in the innermost layer of the epidermis. 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.

What are the 2 types of sweat glands?

Merocrine sweat glands- most numerous and distributed sweat glands. They are simple coiled tubular glands that discharge their secretions directly onto the surface of the skin. Their clear secretion is called sweat. Apocrine sweat glands- coiled tubular glands that release their secretions into hair follicles in the axillae, around the nipples, in the pubic region, and in the anal region.

What are the two major components of the integumentary system?

The Integumentary and Cutaneous membrane

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 hypodermis is gone in an 80 year old which makes it more difficult for their body to retain heat.

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 victim is most likely dehydrated because sweat is no longer being produced. The flushed skin symptom could be due to blood being pumped to the surface (via vasodilation) and dilation of blood vessels in an attempt to release heat, the body temp rises because sweat is not being produced to release heat.

How do sunscreens protect skin?

They contain materials that absorb or block UVA and UVB rays which are believed to cause skin cancers

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

Warm humid climates feel hotter because w loose the cooling mechanism from the saturated water in humid temperature.

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

cleavage lines refer to the natural orientation of collagen fibers in the dermis where incisions perpendicular to cleavage lines can gape and delay healing so it is important to make incisions parallel to cleavage lines so they can heal quickly.