INTEGUMENTARY SYSTEM

To be an organ

• Membranes are organs: mucous serous synovial

• Epithelial membranes: mucous + serous + cutaneous(dry membrane, exposed to air)

• Connective tissue: synovial membrane

Mucous membranes

• Line cavities that open to exterior:– Respiratory: ciliated columnar– Digestive: columnar with microvilli– Urinary: no mucus, moist with urine– Reproductive

• Rests on loose connective tissue: lamina propria

Serous Membrane

• Name by location: closed cavities

• 2 layers: visceral- on organparietal- lines inside of cavity

• Peritoneum: abdomen

• Pluera: lungs

• Pericardium: heart

Synovial membrane

• The only connective tissue membrane

• Line fibrous capsule around joint

• Line bursa: small fluid filled sac

• Line tendon sheath

Integumentary system

• Integumentary system = (organ system)skin + sweat/oil gland + hair/nails

• Skin = cutaneous membrane (organ)

Functions

• Protection from non self – bacteria from heat lossmechanical damagechemical damagethermal damageultraviolet radiation (sunlight)

Functions

• Mini excretory system

• Secretes: urea, salt, water

• Manufactures proteins for immunity and synthesizes vitamin D (needs sunlight)

Functions

• Nervous system

• Skin has receptors in it for nervous input hot/cold pressure/pain

• Nervous system controls sweat glands and capillaries

Revisit synovial membranes

• PROPRIOCEPTION

• Proprioceptors in synovial membrane report to nervous system about location of joint and amount of stretch/slack on each side of joint capsule, tendon etc.

Structure of Integument

• Skin = epidermis + dermis

• Epidermis = keratinizing stratified squamous

• Dermis = dense C.T.

• Cornified: upper layer of epidermis has lots of keratin = hardened

Hypodermis

• Deep to skin: also called subcutaneous

• Not part of skin

• Mostly adipose

• Anchors skin to organs/bones below

Epidermis

• 5 layers: strata• Corneum: 30 cell thick-dead cell remnants

constantly rubbed off- lots of keratin• Lucidum: dead, lots keratin, only in areas

of very thick skin (palms, soles of feet)• Granulosum • Spinosum• Basale: gets nourichment from dermis,

constant cell division-millions of new cells

Vascularity

• Epidermis is composed of epithelium

• Avascular: no direct blood supply

• Can scrape off many layers and not have bleeding.

• Receives blood and nourishment from dermis

• New epidermis every 25-45 days

Cells in skin

• Melanocytes: in stratum basalemake melanin (pigment)sunlight stimulates production

• Phagocytes: in stratum basaleeat foreign substances (protection)

• Sun damage: cause elastic fibers to clump = leathery skincan alter genetic material = cancer

• Darker skin: less cancer

Skin color

• Melanin: yellow - red - brown – black

• Carotene: yellow – orange

• Oxygen: bound to heme in blood. If decrease oxygen looks more blue (cyanosis)

Dermis

• Strong, stretchy = hide (of an animal)

• 2 regions

• I. papillary fingerlike projections on superior surface = papillae– Indent the epidermis above- loops, whorls– For grip and friction– Have capillary loops– Pain/touch receptors (meissner’s corpuscles)

Dermis

• II. Reticular: deepest skin layer– Blood vessels– Sweat/oil glands– Pressure receptors (pacinian corpuscle)– Many phagocytes– Collagen: strong, bind water to keep skin

hydrated– Elastic: for elasticity

• AGE

• Decrease # of collagen and elastic fibers: sag

• Decrease sub Q adipose

Dermis

• Very vascular: lots of blood vessels

• Regulate temperature homeostasis

• Body temp. high Capillaries fill with warm blood: skin red warm – blood cools

• Body temp. low Capillaries close to keep blood in warm part of body: extremities get blue

• Scalp: skin on head has many capillaries: much heat dissipated (lost) from top of head. Head injury = much bleeding

• Southern cow – bigger ears than northernto dissipate heat - elephant

Ischemia

Restriction of blood flow to skin = cell death

• Ulcers: skin breakdown with ▼ blood flow

• Decubitus ulcers = bed sores

Nervous System

• All body systems interact with each other

• Sensors in skin are:

• Nerve cells with specialized end organ

• For pressure, temperature, pain

Skin pathology

• Erythema: red skin– Blush– Inflammation– Fever– Hypertension

• Pallor or blanching: white– Stress– Anemia– Hypotension (decrease blood flow)

Skin pathology

• Jaundice: yellow– Liver disease– Excess bile pigment in tissue

• Bruise = hematoma: blood is out of circulatory system and clotted in tissue. (broken blood vessels)

Appendages