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 organ parietal- 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 loss mechanical damage chemical damage thermal damage ultraviolet 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/coldpressure/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 days

Cells in skin Melanocytes: in stratum basale make melanin (pigment) sunlight stimulates production Phagocytes: in stratum basale eat foreign substances (protection) Sun damage: cause elastic fibers to clump = leathery skin can 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 northern to 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