The System

SKIN

The Integumentary System Integument is Skin and its appendages make up the integumentary system A fatty layer (hypodermis) lies deep to it Two distinct regions

Functions of skin Protection  Cushions and and is waterproof  Protects from chemicals, heat, cold, bacteria  Screens UV Synthesizes with UV Regulates body heat Prevents unnecessary loss Sensory reception ( endings- cutaneous receptors)

Epidermis Keratinized stratified squamous epithelium Four types of cells  – deepest, produce keratin (tough fibrous protein) (protects and waterproofs)  Melanocytes - make dark skin pigment  Merkel cells – associated with sensory endings  cells – macrophage-like dendritic cells Layers (from deep to superficial)  Stratum basale or germinativium – single row of cells attached to dermis; youngest cells w/rapid growth, forms here  Stratum spinosum – spinyness is artifactual; tonofilaments (bundles of ) resist tension  Stratum granulosum – layers of flattened keratinocytes producing keratin (hair and made of it also)  Stratum (only on palms and soles)  Stratum – horny layer (cells dead,old cells, many layers thick, translucent, flake off)

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

Remember… Four basic types of tissue  – epidermis just discussed  Connective tissue – dermis  Nervous tissue

Dermis Strong, flexible connective tissue: your “hide” Cells: fibroblasts, macrophages, mast cells, Fiber types: collagen,, reticular Rich supply of Critical role in temperature regulation (the vessels) Two layers (see next slides)  – areolar connective tissue; includes dermal papillae  Reticular – “reticulum” (network) of collagen and reticular

* Dermis layers * * * Dermal papillae

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

Fingerprints,, footprints Dermal papillae lie atop dermal ridges Elevate the overlying epidermis into epidermal ridges Are “sweat films” because of pores determined creases Deep dermis, from continual folding Fibers : strength and resilience Elastic fibers: stretch-recoil  Striae: stretch marks Tension 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) = below the “Subcutaneous” (Latin) = below the skin Also called “superficial ” “fascia” (Latin) =band; in anatomy: sheet of connective tissue Fatty tissue which stores fat and skin (areolar tissue and adipose cells) Different patterns of accumulation (male/female)

Skin color Three skin pigments  : the most important  Carotene: from and yellow vegies  Hemoglobin: the of light skin Melanin in granules passes from melanocytes (same number in all races) to keratinocytes in stratum  Digested by  Variations in color (High conc. = freckles)  Protection from UV light vs vitamin D?

Skin appendages Derived from epidermis but extend into Include  Hair and hair follicles (made of epithelial & connective tissue)  Sebaceous (oil) glands (most active at puberty)  Sweat ( ) glands  Nails

Nails Of hard Corresponds to hooves and claws Grows from nail

Hair and hair follicles: complex Derived from epidermis and dermis Everywhere but palms, soles, nipples, parts of genitalia * “arrector pili” is smooth muscle ➨➨➨➨➨➨➨➨➨➨➨➨➨➨ ➨➨➨➨➨➨➨➨➨➨➨➨➨ Cuticle ➨➨➨➨➨➨➨➨➨➨➨➨➘ are tiny muscles Attached to hair follicls to pull Hair upright during fright or cold

Functions of hair  – less in man than other mammals SSense light touch of the skin PProtection - Parts RRoot imbedded in skin SShaft projecting above surface Make up of hair – hard Three concentric layers MMedulla ( ) CCortex (surrounds medulla)  (single layers, overlapping)

Types of hair  : fine, short hairs  Intermediate hairs  Terminal: longer, Hair growth: averages mm/week  Active: growing  Resting phase then Hair loss  Thinning – related  Male pattern baldness Hair color  Amount of melanin for black or brown; distinct form of melanin for  White: decreased and air bubbles in the medulla  Genetically determined though influenced by hormones and environment

Sebaceous ( ) glands Entire body except palms and soles Produce sebum by holocrine secretion Oils and

Sweat glands Entire skin surface except nipples and part of external genitalia Prevent overheating cc to 12 l/day! (is mostly water) Humans most efficient (only have) Produced in response to as well as heat

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

Disorders of the integumentary system Burns  Threat to Catastrophic loss of body fluids and fatal circulatory shock Infection  Types First degree – epidermis: redness (e.g. ) Second degree – epidermis and upper dermis: blister Third degree - Infections Skin cancer

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

Critical burns Over of the body has third- degree burns 25 % of the body has second- degree burns Third-degree burns on face, hands, or Estimate by “rule of 9’s” Body is divided Into 9% regions

Scabies  Female mites burrows into the where she lays eggs  Skin-skin contact  Clothing, bedding, towels  Inflammatory elevation of the skin ( papules)

Scabies Sysptoms: - intense itching - skin rashes - produces allergic reaction (eggs) - scratching may cause secondary infection  To help: - medications all over the body

Ringworm

 Fungal infection…not a worm!  Skin-skin contact  Ring-shaped, scaly patches on the skin

Ringworm  Symptoms: - red raised itchy patches with defined edges, lighter in the center - take an appearance of a  To help: - topical antifungal drugs

Impetigo  Superficial skin infection  Bacterial…staphylococcu s or streptococcus  Spread w/ direct contact w/  Thick, yellow crust (commonly on the face)

Infected Wounds  Symptoms: - swelling - pain - fever w/ - bleeding or pus - foul smell  To help: - cleaning - ABX and pain killers

Tumors of the skin Benign, e.g. warts Cancer – associated with exposure (also skin aging)  Aktinic keratosis – premalignant  cell - cells of stratum basale, slow  Squamous cell – keratinocytes. epithelial  Melanoma – melanocytes: most dangerous; recognition: A - Asymmetry B - Border irregularity C - D - Diameter larger than 6 mm

Basal cell carcinoma Sqaumous cell carcinoma Melanoma Skin Cancer

6-35 The Anatomy of a Tattoo

6-37 Ink Matures Fibrin clot Granulation Tisssue

6-38 Epidermis Dermis INK Histology of a Tattoo Granulation tissue

6-39 So where is my tattoo?

6-40 Bad Ink Bad sterilization

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