Bio 180 - Integumentary System - Moraine Valley

Integument

The skin (cutaneous membrane) and accessory structures; the body's first line of defense.

What is the cutaneous membrane made up of?

Dermis

Epidermis

Epidermis

Superficial epithelium

Dermis

underlying connective tissue that contains as extensive blood supply, along with sensory receptors that monitor touch, pressure, temperature, and pain

Where are the accessory structures of the cutaneous membrane located?

The Dermis; then projected into the epidermis

What are some accessory structures of the cutaneous membrane?

Hair

Nails

Exocrine Glands

What separates the integument from the deep fascia around other organs, muscles, and bones?

Hypodermis (superficial fascia)

True or False: Hypodermis is a part of the Integument.

False

Functions of the Skin and the Hypodermis

Protection (Acts as a barrier)

Excretion (Salts, water, and wastes)

Insulation and Evaporation for Maintenance of body temp

Production of melanin and protection from UV rays

Production of keratin*

Acts as water repellent

Synthesis of Vitamin D3

Storage of lipids (in form of adipocytes)

Detection of external stimuli

What are the types of skin

Thick Skin and Thin Skin

Thick Skin Location

Palms of hands and Soles of feet

How many layers of epdermis make up thick skin?

five

Thin Skin Location

All areas that do not contain thick skin

How many layers of epidermis make up thin skin

Four

What differentiates think skin from thick skin

How many layers of dead skin cells are present

Name the five epidermal layers

Stratum Basale

Stratum Spinosum

Stratum Granulosum

Stratum Lucidum

Stratum Corneum

Stratum basale

The innermost epidermal layer; Basale cells and melanin.

Stratum Spinosum

layer immediately superficial to the stratum basale; composed of 8 to 10 layers of keratinocytes bound by desmosomes. Contains dendritic cells.

Which epidermal layer contains dendritic cells?

Stratum Spinosum

What do dendritic cells defend against?

Superficial skin cancers

Microorganisms that penetrate the most superficial layer of the epidermis.

Stratum Granulosum

consists of three to five keratinized layers derived from the stratum spinosum. "Granular" or "grainy".

Define Keratin

tough, fibrous protein that is a main structural component in hair and nails

What is Keratohyaline?

The protein that promotes dehydration of a cell, along with the aggregation of cross-linked fibrin.

Stratum Lucidum

The glassy layer that covers the stratum granulosum in thick skin; devoid of organelles and contains large amounts of densely packed keratin. "lucid"

Which epidermal layer, or strata, is unique to thick skin?

Stratum Lucidum

Stratum Corneum

The outermost layer in both thin and thick skin types. Think "Corns are superficial on skin - top layer".

How many layers of keratinized cells are in the Stratum Corneum

15-30

How often in the stratum corneum shed and replaced?

10-14 days

Keratinization

The formation of a protective, superficial layer comprised of cells filled with keratin

Which pigments are present in the epidermis?

Carotene

Melanin

Carotene

The orange-yellow pigment that normally accumulates in epidermal cells; can be converted to Vitamin A. "Carrot".

Melanin

The brown, yellow-brown, or black pigment produced by melanocytes in the stratum basale; protects the epidermis and dermis from excess ultraviolet radiation.

Jaundice

The yellowing of the skin, eyes, and mucous membranes due to liver pathology; too much bilirubin in the system.

What is responsible for the darkening of the skin?

Pituitary Tumors

What does the Pituitary tumor secrete?

melanocyte-stimulating hormone (MSH)

What does Addison's Disease do to the body?

Addison's Disease causes the pituitary gland to release large amounts of adrenocorticotropic hormone (ACTH), causing more darkening of the skin.

What happens when one has Vitiligo?

Skin color becomes palers due to the immune system attacking melanocytes.

What type of disease is Vitiligo?

Autoimmune

What vitamin is produced with the help of the skin?

Vitamin D3

Calcitriol

essential for normal absorption of calcium and phosphorus in the small intestine

Epidermal Growth Factor

Stimulates cells to reproduce and heal. Mitogenic (mitosis).

Role of Epidermal Growth Factor

Promotes the division of Basale Cells*

Accelerates the production of keratin*

Stimulates epidermal repair and development after injury

•Stimulates synthetic activity and secretion by epithelial cells

Dermis

The layer of tissue between the epidermis and hypodermis.

Two layers of the Dermis*

Papillary Layer

Reticular Layer

How many layers make up the Dermis

Two

What is the papillary layer made up of

Areolar tissue and contains capillaries, lymphatics, and *sensory neurons*

Reticular Layer

deep to the papillary layer; dense irregular connective tissue

IS the reticular layer of the dermis made up of reticular tissue?

NO

Dermatitis*

The inflammation of the dermis, primarily affecting the papillary layer; potentially very painful.

Is pain felt at the papillary level?

No, but signals for pain originate there

What gives the dermis a characteristic strength and elasticity?

The presence of collagen and elastic fibers

Define Skin Turgor*

properties relating to the flexibility and resilience of skin due to water content (gives the dermis resiliency)

Define Cleavage Lines

collagen and elastic fibers in a particular area of the dermis established in parallel bundles

Define Plexus

network of vessels or nerves

Cutaneous Plexus

arteries supplying the area of the hypodermis along its border with the reticular layer

Papillary Plexus

branching network of arteries located inside of the papillary layer

What layer below the dermis has a high venous circulation?*

Hypodermis

Hair

The projections above the surface of the skin found in most external places

Are hair living or dead structures?

Hair is non-living; it was never alive, so it cannot be dead

Root hair plexus

sensory nerves that surround the base of hair follicles

What is the exposed part of the hair (the part we visibly see) called?

Hair shaft

Arrector Pili Muscle

smooth muscle band that extends from the dermis and attaches to a connective sheath of the hair follicle; able to force the hair to stand erect

Hair root

portion of the hair that anchors to the skin at the base of the hair bulb; surrounds the hair shaft

What is the hair shaft made up of?

Keratin

Club hair*

hair at the end of a growth cycle; only at certain parts of our bodies (ie. Pubic or axillary hair)

Lanugo

fine and unpigmented hair associated with embryological development

Vellus hair

fine "peach fuzz" hairs

What kind of hair covers majority of our bodies?

Vellus hair

Terminal (androgenic) hair

heavy, deeply pigmented, and sometimes curly

What type of hair gives off odors?

Androgenic

What produces hair color?

Melanocytes

Holocrine glands*

Accumulate their "products" within them until they rupture; "holo" = Whole, all

Sebacous glands

holocrine glands that discharge an oily lipid secretion into hair follicles

Sebum

mixture of triglycerides, cholesterol, proteins, and electrolytes that deposit on the skin

Apocrine sweat gland

secretes product onto hair follicles; apocrine sweat has a distinct odor

Do apocrine sweat glands work through apocrine secretion?

NO

Through what method do all sweat glands work through?

MEROCRINE SCERETION

Functions of sweat from merocrine sweat glands*

*Cooling the surface of the skin to reduce body temperature*

Excreting water and electrolytes

Providing protection from environmental hazards

Mammary glands

anatomically related to the apocrine sweat glands; produce milk in the female breasts

Ceruminous glands

modified sweat glands in the passageway of the external ear; secretion combines with secretions of sebaceous glands forming cerumen (earwax)

Nails

protect the exposed dorsal surface of the tips of the fingers and toes; help limit distortion of the digits when they are subjected to mechanical stress

Eponychium (cuticle)

area of the epidermis that extends over the exposed nail - where you start producing the nail

Lunula

area below the nail body where blood vessels are obscured - Luna: Looks like half-moon

Keloid

raised scar tissue covered with a shiny, smooth, epidermal surface