TEST 3 - Integumentary system

What are the six functions of the integumentary system?

Protection body temperature regulation sensation metabolic function blood reservoir excretion

How does the skin provide protection?

It blocks injury pathogens UV radiation and prevents water loss

How does the skin regulate body temperature?

Through sweating and blood vessel dilation and constriction

How does the skin provide sensation?

It contains receptors for touch pressure pain and temperature

What metabolic function does the skin perform?

It produces vitamin D when exposed to sunlight

How does the skin act as a blood reservoir?

Dermal blood vessels store about 5 percent of blood volume

How does the skin perform excretion?

Sweat removes water salts and small waste products

What is the epidermis?

The outer avascular layer of skin made of keratinized stratified squamous epithelium

Why is the epidermis avascular important?

It has no blood vessels so it relies on diffusion from the dermis

What is the function of the stratum basale?

It produces new skin cells and contains melanocytes and Merkel cells

What happens in the stratum spinosum?

Keratinocytes strengthen and Langerhans immune cells are present

What happens in the stratum granulosum?

Keratinization begins and cells start dying

Where is the stratum lucidum found?

Only in thick skin like palms and soles

What is the function of the stratum corneum?

It forms a protective layer of dead keratinized cells

What do keratinocytes do?

They produce keratin for protection and waterproofing

What do melanocytes do?

They produce melanin pigment for UV protection

What do Langerhans cells do?

They provide immune defense in the epidermis

What do Merkel cells do?

They function as touch receptors

What is the dermis?

The connective tissue layer beneath the epidermis containing vessels nerves and glands

What is the function of the papillary layer?

It forms fingerprints and contains capillaries and touch receptors

What are dermal papillae?

Projections that create fingerprints and increase surface area

What is the reticular layer?

Deep dermis made of dense connective tissue with collagen and elastin

What is the hypodermis?

The subcutaneous layer made of fat that insulates cushions and stores energy

Why is the hypodermis not technically skin?

It lies below the skin layers and connects skin to underlying tissue

What is melanin?

A pigment that protects skin from UV radiation

What is carotene?

A yellow orange pigment from food that accumulates in skin

What is hemoglobin responsible for in skin color?

It gives skin a pink or red tone

What is keratinization?

The process where cells fill with keratin and become waterproof and strong

What are epidermal ridges?

Fingerprints that improve grip

What are lines of cleavage?

Directions of collagen fibers important for surgical cuts

What are striae?

Stretch marks caused by tearing of dermal collagen

What is a blister?

A fluid filled space between epidermis and dermis

What do sebaceous glands produce?

Sebum which lubricates skin and hair

What is the difference between eccrine and apocrine sweat glands?

Eccrine glands cool body and open to skin surface apocrine glands activate at puberty and open into hair follicles

Where are apocrine glands located?

Armpits and groin regions

What are ceruminous glands?

Modified sweat glands that produce earwax

What is the hair shaft?

The visible part of hair above the skin

What is the hair root?

The part of hair below the skin

What is the hair bulb?

The base where hair growth occurs

What is the hair follicle?

The structure that surrounds and anchors hair

What happens in the anagen phase?

Active hair growth occurs

What happens in the catagen phase?

Hair growth slows and transitions

What happens in the telogen phase?

Hair is in resting phase

What does the arrector pili muscle do?

It causes goosebumps by contracting

What is the root hair plexus?

Nerve endings that sense hair movement

What is basal cell carcinoma?

Most common skin cancer originating in stratum basale

What is squamous cell carcinoma?

Cancer of keratinocytes that can spread if untreated

What is melanoma?

Most dangerous skin cancer from melanocytes

What is a first degree burn?

Damage to epidermis only causing redness and pain

What is a second degree burn?

Damage to epidermis and dermis causing blisters

Why is a third degree burn often painless?

Because nerve endings are destroyed