Chapter 6: Skin

Epidermis

Outer layer

• composed of stratified squamous epithelium

• Basement membrane between epidermis and dermis

• Lack of blood vessels

Dermis

Inner Layer

• thicker than epidermis

• Connective tissue, with collagenous and elastic fibers, muscle, blood, nerve tissue

Subcutaneous layer

(Hypodermis)

Beneath dermis; insulting layer

• areolar and adipose connective tissue

• Not considered part of the skin

• Contains blood vessels that supply skin

Name the epidermal layer that is found in thick skin, but is absent from thin skin

Stratum Lucidum

What is keratinization and where does it occur?

Hardening of cells; occurs in epidermis

Anchoring the epidermis to the superficial dermis is a thin layer called the _______

Basement Membrane

What is the function of the lunula of the nail?

Sit of Nail growth

What is the function of the arrector pili?

To shift position of hair follicles

Increase or Decrease

Vasoconstriction of blood vessels in the dermis of the skin is a response to an _______ in body temperature

Decrease

• skin gets pale or cool so it keeps heat inside the body

As body temperature increases, the blood vessels of the dermis will _______

Vasodilate

• skin gets warmer or red so it helps cool body down

Define the term erythema

Reddened skin

• eryth=red

What type of burn involves the destruction of the epidermis, dermis, and accessory structures of the skin?

Full-thickness burn

(Third degree)

What type of burn involves the destruction of some of the epidermis and some of the underlying dermis?

Deep partial-thickness burn

(second degree)

What type of burn involves injury to only the epidermis?

Superficial partial-thickness burn

(first degree)

As we age, our skin _____

thins/ thinner

How do apocrine glands differ from other skin glands?

Apocrine glands secrete the response to emotional stimuli.

why do cells of the epidermis die as they are pushed towards the surface of the skin?

They are too far from their nutrition supply

The ______ are the bundles of smooth muscle found within the thermos, attached to hair follicles.

Arrector pili

When healing a shallow cut in the skin, the rate of mitosis increases in what layer

Epidermis

Nutrient and oxygen supply from the epidermis comes from blood vessels, located in the ______ layer of the skin

Dermal

Within the epidermis, cell division and growth occurs in the stratum _____

Stratum basale

Merocrine(eccrine) sweat glands are located ______ and function to ______

Almost everywhere in the body; cool the skin

Arrector pili are located in the dermis of the skin. What are they?

Smooth Muscle

What type of dead cells make up a hair?

Epithelial cells

One response to increase internal body temperature is an increase in blood flow to the skin due to the ______ of dermal blood vessels

Vasodilation

Burns classified as ______ burns heal quickly with no scarring.

Superficial partial-thickness

(first degree)

What variation in melanin accounts for the differences in skin tone between individuals?

Differences in the amount of melanin produced

What structures are part of the integumentary system?

• skin

• Hair and nails

• Sebaceous (oil) glands

• Sweat glands

• sensory receptors

What are the two layers of the skin?

• Epidermis

• Dermis

Which tissues forms the epidermis of the skin?

Stratified squamous epithelium

What layer of the skin lacks blood vessels?

The epidermal layer

Lack of blood supply within the epidermis is the cost for what characteristic of epidermal cells?

Cells near the skin surface are dead

The skin contains two distinct layers, the _______ and the _______

Epidermis; Dermis

The stratum corneum of the epidermis is made of ______

Many layers of tough, tightly packed, dead cells

The epidermis only contains one type of tissue, namely ______ ______ epithelium

Stratified squamous epithelium

Where in the body is thick skin, with five epidermal layers, found?

Palms of hands and soles of feet

Which statement describes the stratum basale of the epidermis?

It contains cells that are dividing

Why do the cells of the epidermis die as they are pushed towards the surface of the skin?

There are too far from their nutrient supply

The outermost layers of the epidermis are called the stratum ______

Stratum Corneum

The palms of the hands and the souls of the feet are covered with _____ skin

Thick

The epidermis of thick skin contains an extra layer, called the stratum ______. This layer is typically lacking in thin skin

Stratum Lucidum

Where are the body is thin skin (with four epidermal layers only) found?

Most body areas except palms and soles

The production of new skin cells in what layer typically keeps pace with the loss of cells from the stratum corneum?

Stratum basale

The pigment melanin produced by _____ and contributes to the color that is observed in the skin

Melanocytes

The substances called _______ is produced in specialized skin cells. It absorbs ultraviolet radiation from sunlight, preventing it from causing mutations in the DNA of skin cells.

Melanin

Most body areas, such as the arms and the legs are covered with ______ skin

Thin

Cell division by cells of the stratum _____ replaces the shedding skin cells of the stratum corneum

Stratum Basale

How is melanin protective ?

It absorbs UV radiation from sunlight

The primary determinant of skin color is a pigment-protein called _______

Melanin

What is the tubelike depression from which a hair grows and emerges at the skin surface?

Hair follicle

Which of the following are function of the sebum?

• it lubricates hair

• It waterproofs the skin

• It softens skin

The skin does play an important role in the production of vitamin _____

D

The steps in the production of vitamin D as they occur…

1. Production of dehydrocholestrol in skin cells

2. Production of cholecalciferol with the help of sunlight

3. Production of calcitriol in love and kidney cells

The secretion called ___lubricates hair and makes skin soft, pliable, and waterproof

Sebum