Integumentary System

Main Functions

Physical Protection

Sensation

Thermoregulation

Vitamin D synthesis

Characteristics of physical protection function

-Moisture barrier, water resistance

-Cushioning via adipose tissue

-Nails protect ends of fingers and toes

-Immunity

Immunity characteristics of physical protection

-First barrier against infection

-Acidic mantle and peptides/lipids on skin suppress bacterial growth

Sensation characteristics

Innervation by various sensory nerve endings to discriminate pain, temp, touch and vibration

Thermoregulation characteristics

-Large surface area and highly vascularized

-Hair on skin

Vitamin D synthesis characteristics

-UV light exposure

-Production of cholecalciferol that goes to live then kidney for activation

Skin ranges in __________

Thickness

Average skin thickness

thinest -->thickest mm

Average 1-2 mm

.5 mm on eyelids to 5mm on back

Thickness is based on the _________ alone

epidermis

What is the epidermis layer composed of?

stratified epithelial cells thatfurther break down into four to five layers

5 layers of the epidermis

stratum corneum,

stratum lucidum,

stratum granulosum, stratum spinosum,

stratum basale

Cells within the epidermis layer

Langerhans Cells

Kerantinocytes

Melanocytes

Merkel Cells

What does the stratum basale layer of the epidermis consists of?

layer of stem cells thatcontinually undergo mitosis producingnew skin cells

Kerantinocytes Function

Produce keratin; water barrier; calciumabsorption; helps form hair, nails, and epidermis

Langerhans' Cells

Skin's first-line defenders (immune system in theskin)

Melanocytes

Primarily produces melanin (pigment of the skin),UVB light stimulates melanin secretion, which isprotective against UV radiation, acting as anatural sunscreen

Merkel Cells

Mechanoreceptors for a light touch and pressure

The epidermis layer DOES NOT have its own...

Blood vessels or nerves

How does oxygen and nutrients get to the epidermis

Through diffusion from the dermis

What is the dermis layer composed of?

Connective Tissue

What fibers does the dermis layer primarily contain?

Collagen

Elastin

Reticular

Collagen fibers

Strengthen tissue

Elastin fibers

Add Elasticity

Reticular fibers

Bind collagen and elastin fibers together

2 layer within the dermis

Papillary

Reticular

Cells and Structures of the Dermis Layer

-Blood vessels

-lymph vessels and immune cells

-nerve endings/receptors

-collagen and elastin

-sebaceous (oil) glands

-sweat glands

-Hair follicles

What strcuture of the dermis supplies nutrients and oxygen to the skin and remove cell waste/products

Blood Vessels

What strcuture of the dermis transport the vitamin D produced in the skin back to the rest of the body

Blood Vessels

What strcuture of the dermis is involved with the immune system

Lymph vessels and immune cells

What strcuture of the dermis transmits sensation of itch, pain, touch and texture, etc

Nerve endings/ receptors

What strcuture of the dermis supports the epidermis, lending it its durabilitySpring back into place when stretched and keeps the skin flexible

Collagen and Elastin

What strcuture of the dermis secrete oil that helps keep the skin smooth & waterproof; protects against an overgrowth of bacteriaand fungi on the skin

Sebaceous (oil) glands

What strcuture of the dermis secrete a milky sweat that encourages the growth of the bacteria responsible for body odor; regulatebody temperature by bringing water via the pores to the surface of the skin, where it evaporates andreduces skin temperature

Sweat glands

What strcuture of the dermis are skin structures from which hair grows; distribute the oil produced by sebaceous glands onto the skin'ssurface

Hair Follicles

Where does the hypodermis situated

Between dermis and underlying organs

What is the hypodermis layer composed of?

connective & adipose tissues

Function of hypodermis layer

-Provides additional cushion and insulationthrough its fat-storage function

-Connects the skin to underlying structures such as muscles

Shaft of hair

Part of the hair that extends above the skin's surface

hair follicle

Sheath of epidermis that each hair lies within - rich nerve and blood supply

Bulb/root

Lowest part of the hair and is where growth occurs

Papilla

Cluster of connective tissue and blood vessels at the base of the hair

Arrector Pili

Small bundle of smooth muscle attached to each hair follicle

Cuticle

Fold of skin that surrounds nail body

Nail Body

Visible part of the nail

Lunula

Crescent shaped white area at the base of the nail

Nail bed

Layer of epithelium under the nail- normally appears pink because of the rich blood supply

Nail Root

Proximal end of the nail- hidden under overlying tissue

Venous Ulcers

Typically caused by inflammatory processes secondary to venous reflux and hypertension

Arterial Ulcers

Most common predisposing condition is peripheral vascular disease affecting lower extremity that supply the leg and foot

Neuropathic Ulcers

Patients with diabetes mellitus generally at higher risk for this type due to predisposing factors such as neuropathy and localized ischemia

Stage 1 Wounds

The skin is intact with nonblanchable erythema

Stage 2 Wounds

Partial-thickness skin loss involving the epidermis and dermis

Stage 3 Wounds

A full-thickness loss of skin extending to the subcutaneous tissue but does not cross the fascia beneath it

Stage 4 Wounds

Full thickness skin loss extends through the fascia with considerable tissue loss; may be muscle bone, tendon or joint involvement

Phases of wound healing

Vascular, inflammatory, proliferation, remodeling

Vascular phase

-Exposure of collagen clotting cascade

-Thrombocytes trigger vasoconstriction leading to hemostasis

-Blot clot forms a temporary wound matrix

-Vasodilation leads to edema

Time for vascular phase

Seconds/minutes

Inflammatory Phase

-Neutrophil recruitment and migration along a chemokine gradient

-Monocyte migration into wound site and differentiation into macrophages

-Phagocytosis to clean the wound from bacteria and cell debris

Time for inflammatory phase

Days

Proliferation phase

-Fibroblast-myofibroblast activity

-Endothelial cell activity initiates angiogenesis

-Extracellular matrix deposition

Time for proliferation phase

days to weeks

Remodeling phase

-Increase in wound stability

-Apoptotic processes to diminish overall cellular wound content

-Avascular and acellular scar tissue

Time for remodeling phase

months to years