Integumentary System Anatomy and Physiology Honors Unit 3

How can you identify a skin cancer mole/melanoma?

ABCDE rule

What is the ABCDE rule?

Asymmetry, Border (outer edges or uneven), Color (dark black or have multiple colors), Diameter (greater than 6mm), Evolving (change in size, shape and color)

What are the functions of the skin?

•Protection from water, air,
infection, chemicals, UV radiation.
•Sensations such as pressure, heat, cold,
& pain.
•Temperature regulation- body can be
heated or cooled by sweat and blood
flow near surface.
•Excretion of waste through sweat.
•Production of Vitamin D.

What are the layers of the skin in order?

Epidermis → Dermis → Hypodermis

What are the layers of the epidermis?

-Top layers are composed stratified squamous epithelial tissue

Stratum Corneum, Stratum Lucidum, Stratum Granulosum, Stratum Spinosum, Stratum Basale

What is the Stratum Corneum?

-Layer of dead cells that are 20-30 thick.

-Composed of keratinized cells that protect the deeper layers.

-Are regularly shed

What is the Stratum Lucidum (Clear Layer)?

A thin layer of translucent cells ONLY found in thick skin of the palms and soles of feet.

What is the Stratum Granulosum?

-Cells here begin to flatten and disintegrate.

-Accumulate keratin granules, responsible for water-proofing the skin

What is the Stratum Spinosum “Spiny Layer”?

-Named for the irregular shape of the cells.

-Several cells thick.

-Contains pre-keratin filaments.

What is the Stratum Basale?

Constantly dividing and pushing up cells into the next layer.

How do melanocytes protect the body?

-Melanocytes are spider-shaped
epithelial cells found in the bottom 2
layers of the epidermis (Stratum
Basale & stratum spinosum)

-Melanocytes produce a pigment
called melanin, which is absorbed by
the nearby epidermal cells.

-Melanin protects the skin against harmful UV rays.

How do darker skinned and lighter skinned people differ in amount melanocytes?

Darker-skinned people have the same number of melanocytes, but the amount of melanin produced differs from lighter-skinned people.

What happens when UV radiation mutates a skin cell’s DNA?

The cells begin to divide uncontrollably, this can cause skin cancer.

What are the different types of skin cancer?

-Melanoma- uncontrolled division of melanocytes
-Basal cell carcinoma- uncontrolled division of cells in the stratum basale layer
-Squamous cell carcinoma- uncontrolled division of cells in the stratum
spinosum layer

What tissue is the dermis composed of?

Dense Irregular Connective Tissue

What does the dermis contain?

Nerves, Blood Vessels, Sweat Glands, and Hair Follicles

What is the boundary between the epidermis and the dermis?

Wavy layer called the Dermal Papillae

What does the Dermal Papillae do?

-The Dermal Papillae forms your fingerprint (Epidermal ridges)

-The Epidermal ridges increase friction allowing us to pick up objects more easily

What are the characteristics of the dermis?

-Composed of 2 layers: Papillary layer (Loose connective) and Reticular layer (Bundles of collagen fibers)

-Arrangement of collagen fibers causes lines of cleavage or lines of tension.

Why are lines of cleavage important?

-Lines of cleavage
are important to
surgeons.

-Cuts should be
made parallel to
the lines of
cleavage for
quicker healing
and less scar tissue
formation.

How can blood flow in the dermis change?

-During exercise, the blood vessels in the dermis
swell causing skin to appear red.

-This allows heat from the blood to dissipate,
cooling the body.

-When blood supply to the skin is restricted for a
prolonged time, decubitus ulcers (bedsores) can
form.

What are the characteristics of the hypodermis?

-Known as the
subcutaneous layer

-Not actually a part of
the skin

-Composed of loose,
fatty connective tissue
that connects the skin to
muscle or bone

-Also insulates and stores
nutrients

What are the 2 types of glands found in the skin?

-Sudoriferous
(sweat) glands

-Sebaceous (oil)
glands

What are the characteristics of the Sudoriferous (sweat) glands?

-More than 2.5 million per person

-2 types of Sudoriferous glands: Eccrine and Apocrine

What is the Eccrine?

-Merocrine sweat glands that are abundant and often found on the palms, soles of feet, and forehead

-Long tubes that open into pores on the surface of the skin

What is the Apocrine?

-Found almost exclusively in the armpit and genital areas

-Apocrine sweat glands contain all the traditional components of sweat PLUS fatty substances and proteins.

-Originally odorless, but bacteria begin to breakdown fat & proteins causing body odor.

-Increase during puberty & may be similar to scent glands of animals.

What is Sweat?

-Sweat is 99% water with trace amounts of salts, vitamins, wastes, and an antimicrobial peptide called dermcidin.

-Sweat is generally acidic.

What are the characteristics of the sebaceous (oil) glands?

-Produces sebum (oil)

-Sebaceous glands

-Function: lubricates skin and hair,
kills bacteria

-The amount of oil produced is based on inheritance, but usually
increases during puberty.

Where is sebum (oil) usually found?

Usually secreted onto hair, there are more oil glands on the scalp and face and none on palms or soles of feet

What type of glands are Sebaceous glands?

Holocrine glands (whole burst cells)

What is hair and nails made of?

Hard keratin

What is the function of hair?

-Head hair keeps in heat and protects us from the sun

-Body hair alerts us to insects

-Eyelashes protect the eyes

-Nose hair prevents the entry of foreign objects

What is the structure of hair?

-The part of the hair that sticks out of the skin is called the shaft.

-It is protected by the outermost layer called a cuticle.

What is the structure of nail?

Nails are protective and useful as tools.

Nail has 4 basic parts:
Free Edge (Visible)

Body (Visible)

Root (Not Visible)

Nail Bed (Not Visible)

How are nails formed?

-The nail matrix produces heavily keratinized cells, which become the nail body.
-The nail is protected on three sides by nail folds.

What is the Lunula?

“little moon”; whiter due to thickness of nail

What is the Eponychium?

The cuticle, it provides a protective seal for the nail matrix.

What happens in a severe burn cycle?

Fluids and heat is loss
Damaged dermis is unable to regenerate
Temperature and fluid levels are stabilized through medical innovation
Homeostasis Regulation

What happens in a superficial burn cycle?

Fluids and heat is loss
Intact dermis regenerates
Fluid and temperature are stabilized
Homeostasis Regulation