final chapter 5 lectures 8-9

functions of the integumentary system

protection
sensation
temperature regulation
vitamin d production
excretion

protection

the skin is the covering of the body and acts as a barrier, protecting the body from UV light, microorganisms, and prevents dehydration

sensation

the integumentary systems has sensory neurons that detect heat, cold, touch, pressure, pain

temperature regulation

the skin plays a major role in regulating body tempature through modulation of blood flow through the skin and the activation of sweat glands

vitamin d production

when exposed to ultraviolet light the skin, produces a molecule that can be transformed into the hormonal form of vitamin D an important regulator of calcium homeostasis

excretion

small amounts of waste products are excreted through skin glands

the skin is made up of two major tissue layers

a superficial epidermis and a deeper dermis

epidermis

The superficial layer of skin consists of stratified squamous epithelial tissue

protects against potential damages from abrasion and reduces water loss

dermis

a layer of connective tissue. It gives the skin its strength and durability, for instance, leather is composed of animal dermis that is preserved in a process called tanning.

superfical → deep epidermis layers

stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale

basement membrane

ECM that sperates dermis from epidermis

stratum basale

deepest layer of epidermis a single layer of cells attached to basement membrane by heimdesmosomes

home to mealanocytes

stratum spinosum

8-10 layers of recently born keratinocytes. As these cells move superficially, they begin to flatten and produce a fiber called keratin

melanocytes

the cells that produce the protein melanin that gives skin its pigment

stratum granusolum

2-5 layers of flattened cells. here is where cells die

stratum lucidum

3-5 layers of dead and transparent cells. only present in thick skin, absent in most thin skin

stratum cornium

25 or more layers of dead squamous cells and keratin fibers. These layers prevent water loss and protect against abrasion

factors that determine skin color

pigments in the skin, blood ciruclation

melanin

A group of pigments primarily responsible for skin, hair, and eye color

blocks UV light and protects stem cells of the stratum basale

phagocytosed by keratinocytes.

large amounts of melanin are found in certain regions of the body such as

freckles, moles, nipples, areolae of the breasts, axillae(arm pit), and the genitalia.

fastest to slowest absorption

intravenous, intramuscular, subcutaneous, intradermal

intravenous

injections directly into the blood via vein
25 degrees
saline, diuretics

intramuscular

injections into the muscle which is quickly absorbed by surrounding blood vessels
90 degrees
steroids antibiotics vaccines

subcutaneous

Injections into the hypodermis are mostly fat and collagen. This area has little blood supply
45 degrees
insulin and blood thinner

intradermal

Injections into the dermis with very slow absorption and allows for longer-lasting effects of drugs.

10-15 degrees
allergy testing

pressure ulcers (bedsores)

are injuries to the skin and underlying tissues resulting from prolonged pressure on the skin

pressure ulcer causes

Lesions are caused by a lack of blood flow to areas, typically occur over bone prominences (tailbone, shoulder blade, back of head, elbow), can develop in just hours, most heal incompletely, and prevention is the best treatment; can be lethal if sores become infected. 

treatment of pressure ulcers

cleaning and bandaging the wound, removing damaged tissue(debride) some may require surgery, negative pressure: vacuum-assisted closure, or would vac to help promote blood flow.

preventing bedsores in elderly patients

Frequent body repositioning, skin care regimens, special mattresses, proper nutrition, quitting smoking, exercising, and ensuring proper fluid intake.