The Integumentary System The Integumentary System Integument is

The Integumentary System

The Integumentary System Integument is_____ n Skin and its _____make up the integumentary system n A fatty layer (_____) lies deep to it n Two distinct regions n ¨ __________

Functions of skin ¨ ______ ¨ Cushions and insulates and is waterproof ¨ Protects from chemicals, heat, cold, bacteria ¨ Screens UV n n Synthesizes _____ with UV Regulates _________ Prevents unnecessary ____ loss _____ reception (nerve endings)

Epidermis n n Keratinized stratified squamous epithelium Four types of cells _____ – deepest, produce keratin (tough fibrous protein) ¨ _____ - make dark skin pigment melanin ¨ ______– associated with sensory nerve endings ¨ ______ cells – macrophage-like dendritic cells ¨ n Layers (from deep to superficial) ¨ ¨ ¨ Stratum _______ or germinativum – single row of cells attached to dermis; youngest cells Stratum _____ – spinyness is artifactual; tonofilaments (bundles of protein) resist tension Stratum _____ – layers of flattened keratinocytes producing keratin (hair and nails made of it also) Stratum ______ (only on _______ and _______) Stratum ______ – horny layer (cells dead, many layers thick) (see figure on next slide)

Epithelium: layers (on left) and cell types (on right)

Remember… n Four basic types of tissue ¨______ – epidermis just discussed ¨______ tissue - dermis ¨__________ tissue

Dermis n n n Strong, _____ connective tissue: your “hide” _______: fibroblasts, macrophages, mast cells, WBCs Fiber types: ____, _______, reticular Rich supply of ____ and ____ Critical role in _____ regulation (the vessels) Two layers (see next slides) ¨ ______ – areolar connective tissue; includes dermal papillae ¨ ______ – “reticulum” (network) of collagen and reticular fibers

*Dermis layers *Dermal papillae * *

Epidermis and dermis of (a) thick skin and (b) thin skin (which one makes the difference? )

Fingerprints, palmprints, footprints n n Dermal _____ lie atop dermal ridges _____ the overlying epidermis into epidermal _____ Are “_______” because of sweat pores _______ determined _______ creases n Deep dermis, from _______ folding Fibers n n _____: strength and resilience Elastic fibers: stretch-recoil ¨ n _______: stretch marks ______ lines (or lines of cleavage) ¨ The direction the bundles of fibers are directed The dermis is the receptive site for the pigment of tattoos

Hypodermis “Hypodermis” (Gk) = _____ the skin n “Subcutaneous” (Latin) = ____ the skin n Also called “_____” n “fascia” (Latin) =band; in anatomy: sheet of connective tissue ______ tissue which stores fat and anchors skin (_______ tissue and _____ cells) n Different patterns of accumulation (male/female) n

Skin color n Three skin pigments ¨ ____: the most _____ ¨ _____: from ____ and _____ ¨ _____: the ______ of light skin n _______ in granules passes from ____ (_____ number in all races) to keratinocytes in stratum basale ¨ _____ by lysosomes ¨ _____ in color ¨ Protection from UV light vs vitamin D?

Skin appendages Derived from epidermis but ______ into dermis n Include n ¨ Hair and _____ follicles ¨ _____ (oil) glands ¨ _____ (sudoiferous) glands ¨ Nails

Nails Of hard _____ n Corresponds to ____ and _______ n Grows from nail _______ n

Hair and hair follicles: complex Derived from epidermis and dermis Everywhere but ______, parts of _______ * *“arrector pili” is smooth muscle Hair bulb: epithelial cells surrounding papilla Hair papilla is connective tissue________

n Functions of hair ¨ _______ – less in man than other mammals ¨ Sense _______ touch of the skin ¨ _______ - scalp n Parts ¨ ____ imbedded in skin ¨ ____ projecting above skin surface Make up of hair – _______ n Three concentric layers n ¨ _____ (core) ¨ _____ (surrounds medulla) ¨ _____ (single layers, overlapping)

n Types of hair ¨ _______: fine, short hairs ¨ __________: longer, courser n Hair growth: averages 2 mm/week ¨ _______: growing ¨ Resting phase then n hair shed Hair loss ¨ Thinning – age related ¨ Male pattern baldness n Hair color ¨ _______ of melanin for black or brown; ____ form of melanin for red ¨ _____: _______ melanin and ______ in the medulla ¨ ______ determined though influenced by hormones and environment

Sebaceous (oil) glands n n n Entire body except ______ and ____ Produce _____ by holocrine secretion Oils and lubricates

Sweat glands n n n Entire skin surface except ______s and part of ______ genitalia Prevent overheating _____ cc to _____ (is mostly water) Humans most efficient (only ______ have) Produced in response to _____ as well as ______

Types of sweat glands n Eccrine or merocrine ¨ Most numerous ¨ True sweat: 99% water, some salts, traces of waste ¨ Open through pores n Apocrine ¨ Axillary, anal and genital areas only ¨ Ducts open into hair follices ¨ The organic molecules in it decompose with time - odor n Modified apocrine glands ¨ Ceruminous – secrete earwax ¨ Mammary – secrete milk

Disorders of the integumentary system n Burns ¨ Threat to life n ____ loss of body fluids n ______ and fatal _____ shock n Infection ¨ Types n First degree – _______: redness (e. g. _______) n Second degree – _______ and upper _____: ______ n Third degree - full thickness Infections n Skin cancer n

Burns First-degree (epidermis only; redness) Second-degree (epidermis and dermis, with blistering) Third-degree (full thickness, destroying epidermis, often part of hypodermis)

Critical burns n n n Over ____ of the body has ____ burns ______ of the body has second -degree burns Third-degree burns on _____, or _____ Estimate by “rule of 9’s”

Tumors of the skin Benign, e. g. warts n Cancer – associated with UV exposure (also skin aging) n ¨ _______ keratosis - premalignant ¨ ______ cell - cells of stratum basale ¨ _______ cell - keratinocytes ¨ _______ – melanocytes: most dangerous; recognition: A - Asymmetry n B - Border irregularity n C - Colors n D - Diameter larger than 6 mm n

Skin Cancer Sqaumous cell carcinoma Basal cell carcinoma Melanoma