Integumentary PT: Anatomy and Physiology

SKIN, HAIR, OIL GLANDS, SWEAT GLANDS, NAILS AND SENSORY RECEPTORS

Components of Integumentary System

Sensing (sensory information), Thermoregulation, and Protection

3 Main Functions of Integumentary System

Epidermis, Dermis, Hypodermis

What are the layers of the skin

Epidermis

Skin layer that's avascular and consists of epithelial tissue

Dermis

Layer of the skin containing fibrous or dense connective tissue.

Hypodermis

Not really a part of the skin though share some protective function with it. Mostly adipose tissue

Adipose tissue

A component of hypodermis that acts as shock absorber, anchors the skin, and store fat.

Keratinocytes

Main role is to produce keratin

Melanocytes

Cell found at the deepest layer of epidermis

Dendritic Cells or Langerhans Cell

Star-shaped macrophages that patrol the epidermis

Merkel Cells

Sense touch and shaped like spiky hemisphere

Keratinocyte

has keratin content made up of intermediate filament

Melanocyte

Has melanin granules which acts for skin protection

Merkel Cell

Has merkel disc which provides skin with sensory function

Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum

5 layers of epidermis

Stratum basale

aka stratum germinativum

10-25%

Percentage of melanocyte in stratum basale

adipose tissue

Acts as shock absorber, anchors the skin, and stores fat

25-45 days

Old epidermal cells are replaced by new ones every \_____.

Dendritic cells

Cells that are key activators of immune system

Stratum lucidum

Strata that's absent in thin skin

Stratum spinosum

Cells contain weblike system of intermediate prekeratin filaments attached to desmosomes allowing it to resist tension and pulling

Stratum spinosum

Keratinocytes on this layer are spiky hence they're called prickle cells

3-5 layers

number of cell layers on stratum granulosum

Stratum granulosum

In this layer, cells begin to change appearance such as flattening of cell and disintegrating of organelles and nuclei

Stratum lucidum

Cell above this layer dies due to distance from capillaries of dermis

Papillary Layer

Thin superficial layer of areolar connective tissue consisting of loose, interlacing collagen and elastic fibers and blood vessels form a loosely woven mat that is heavily invested with small blood vessels.

Dermal papillae

superficial region of dermis that sends fingerlike projections

Dermal papillae

these projections contains capillary loops, free nerve endings, and touch receptors (tactile

Reticular Layer

layer that consists of coarse, dense fibrous connective tissue

Cleavage (tension) lines

Collagen fibers run in various planes but most run parallel to the skin surface

Flexure lines

dermal folds at or near joints. Skin's inability to slide easily for joint movement causes deep creases

Reddish yellow to Brownish black

Melanin gives off what color

tyrosinases

Synthesis of melanin depends on an enzyme in melanocytes called __________

Carotene

Yellow to orange pigment

Carotene

Pigment most obvious in palms and soles

Carotene

Accumulates in stratum corneum and fatty tissue of hypodermis

Cyanosis

When hemoglobin is poorly oxygenated both the blood and the skin of Caucasians appear blue.

Erythema

Indicates embarrassment, blushing, fever, hypertension, inflammation or allergies.

Pallor (blanching or pale color)

Appears during fear, anger, other types of emotional stress. It also signifies anemia or low blood pressure.

Jaundice (yellow cast)

abnormal yellow skin tone usually signifies a liver disorder in which yellow pigment called bile accumulates in the blood and is deposited in the body tissues.

Metallic skin / bronzing

a sign of Addison's disease in which the adrenal cortex produces inadequate amounts of steroid hormones or a sign of pituitary gland tumors.

Bruises (black and blue marks)

when blood escapes from the circulation and clotted beneath the skin. Clotted bloods are called "hematoma" (blood swelling).

Hair shaft

area that extends above scalp, where keratinization is complete

Hair root

area within scalp, where keratinization is still going on

Hair bulb

expanded area at deep end of follicle (4 mm below the skin surface)

Hair matrix

actively dividing area of bulb that produces half cells originate in hair bulge

arrector pili mm

small band of smooth muscle attached to follicle.

Hair Papilla

nipple-like bit of dermal tissue that protrudes into the hair bulb

Vellus Hair

pale, fine body hair of children and adult females.

Terminal hair

coarse, long hair Found on scalp and eyebrows

Alopecia

hair thinning in both sexes at the age of 40

True (frank) baldness

Genetically determined and sex-influenced hair condition

Nail

Act as a (clear) protective cover for distal, dorsal surface of fingers and toes

Nail bed

epidermis underneath keratinized nail plate.

Nail matrix

thickened portion of bed responsible for nail growth.

Nail folds

skin folds that overlap border of nail

Eponychium

nail fold that projects onto surface of nail body; also called Cuticle.

Hyponychium

area under free edge of plate that accumulates dirt

Lunula

thickened nail matrix, appear white

Sweat glands

Also called Sudoriferous glands

Eccrine (merocrine) sweat glands & Apocrine sweat glands

Two main types of sweat glands

eccrine sweat glands

Abundant on palms, soles, and forehead. Each is a simple coiled tubular gland and the secretory part lies coiled in the dermis and the duct extends open in a funnel-shaped pore at the skin surface.

apocrine sweat glands

Secrete viscous, milky or yellowish (color) sweat that contains fatty substances and proteins

Sebaceous (oil) glands

widely distributed, except for thick skin of palms and soles, secret sebum

Thermoregulation, Storage of blood, protection, cutaneous sensations, excretion and absorption, synthesis of Vitamin D

Function of skin

Keratin, Tightly interlocked keratinocytes, Lipids, Oily sebum, Acidic pH of perspiration, Melanin, Intraepidermal macrophages, Macrophages in dermis

Protection of the skin

Pain and nerve endings (tactile discs - epi; Pacinian corpuscles - dermis; hair root plexuses - hair follicle)

Cutaneous sensations

400 mL

Water that evaporates thru the stratum corneum despite being naturally water proof

Sweat

Lipid soluble materials (Vit A,D,E,K) (drugs) 9O2 and CO2)

Toxic materials

heavy metals (lead, mercury, arsenic) (sub in poison ivy and poision oak)

Topical steroids

(i.e., cortisone) are lipid-soluble and move easily into the papillary region of the dermis.

Fibrosis

process of scar tissue formation

Hypertrophic scar

a scar that remains within boundaries of the wound

Keloid scar

a scar that extends beyond the boundaries into normal surrounding tissues

Epidermal wound healing

Does not result in scar formation; Abrasion and minor burns

Deep wound healing

There is formation of scar tissue which causes the healed tissue to lose some of its normal function;

Bones

provide a resting ground for muscles and protection of vital organs

Long bone

longer; Upper and lower limbs

Short bone

Wide; write and ankle

Flat bone

Thin and flattened; skull bones, ribs, scapulae, sternum

Irregular bones

do not fit into categories; vertebrae and facial bones

Diaphysis, Epiphysis, articular cartilage, epiphyseal plate

Structure of long bone

Diaphysis

consists of a central shaft

epiphysis

Two end of long bone

articular cartilage

thin layer that covers the end of epiphyses

epiphyseal plate

growing long bone have ____ composed of cartilage, between each epiphysis and diaphysis

Osteoblast, osteocytes, osteoclast

Cellular components of bones

Osteoblast

functions in the formation, repair and remodeling of bone

Osteocytes

when osteoblasts is surrounded by matrix; mature bone cells

Osteoclasts

contribute to bone repair and remodeling by removing existing bone

lamellae

thin sheets of extracellular matrix

lacunae

Osteocytes are located between the lamellae within the spaces

Canaliculli

tiny canals that connect the lacunae

cavities

The spaces are filled with soft tissue called marrow; such as the large

Yellow Marrow

consist mostly of adipose tissue or fats

Red Marrow

consist of blood-forming cells and the only site of blood formation

periosteum

Outer; Outer surface is covered by dense connective tissues

endosteum

Inner; The surface of medullary cavity is lined with a thin connective tissue membrane

Compact

Forms most of the diaphysis of a long bone and the thinner surfaces of other bones