Chapter 5 💁

athlete's foot

A fungal infection of the skin, especially between the toes; causes itching, redness, and peeling. Also called tinea pedis.

Hypodermis

AKA Subcutaneous layer -Pads and protects the body and its parts, acts as an energy reservoir, and provides thermal insulation. *Drugs are often injected into the subcutaneous layer be- cause its excessive vascular network promotes rapid absorption.

Friction Ridges

Found on fingers, palms, soles, and toes -Formed from large folds and valleys on both epidermal and dermal tissue -Helps grasp objects -Increase friction so that items don't slip. (so you don't fall on your ass when you walk barefoot, or maybe your just drunk idk) -Fingerprints (dermatoglyphics) -Each individual has a unique pattern -Valuable tool for law enforcement

Hair Growth & Replacement

Hair Loss -Can be temporary (drugs, dietary factors, radiation, high fever, stress) -Thinning (alopecia) (both sexes, result of aging, change in texture)

Skin Color

Hemoglobin: oxygen biding protein present in red blood cells. Upon binding with oxygen, exhibits a bright red color (the redder, the healthier) Melanin: produced in melanocytes. yellow, reddish, tan, brown and black shades Carotene: mostly comes from diet hoe

blister

blister A thin-walled, fluid-filled sac either internal to or within the epidermis; caused by a burn or by excessive friction.

Exocrine Glands

(in reticular layer) sweat (sudoriferouse) glands -Merocrine glands: sweat gland duct carries the secretion to the surface of the epidermis. Distributed throughout body, except external genitalia, nipples, and lips; especially prevalent on palms, soles, and forehead Produce nonviscous, watery secretion; controlled by nervous system; provide some antibacterial protection; function in thermoregulation and excretion; flush surface of epidermis -Apocrine glands: sweat gland duct carries the secretion into hair follicle. Distributed in axillary, anal, areolar, and pubic regions. Produces viscous, complex secretion; secretion influenced by hormones; may act in signaling/communication *Both have myoepithelial cells ( In response to sympathetic nervous system stimulation, myoepithelial cells con- tract to squeeze the gland, causing it to discharge its accumulated secretions into the duct.) sebaceous glands -Associated with hair follicles; Produce lipid material called sebum, which coats epidermis and shaft of hair; provide lubrication and antibacterial activity Ceruminous glands: External acoustic meatus; secretes Cerumen (ear wax) Mammary glands: Breasts; Milk to nourish offspring

Dermis

-Composed of cells of the CT proper and primarily collagen fibers, but elastic and reticular fibers are also present -Also contains blood vessels, sweat glands, sebaceous glands, hair follicles, nail root, nerve endings, & muscular tissue *Reticular layer stretches (stretch marks). Like leather

Dermis: Reticular Layer

-Deep layer -Extensive innervation -Dense irregular connective tissue through which large bundles of collagen fibers project in all directions. These fibers are interwoven into a meshwork that surrounds the structures in the dermis -The word reticular in the name of this layer means "network" and refers to the meshwork of collagen fibers. These interwoven collagen fiber bundles obscure any distinct boundary between the papillary and reticular layers. -Collagen fibers extend internally from the reticular layer of the dermis into the underlying subcutaneous layer.

Hair 💇

-Found everywhere except palms, soles, genitalia, lips -Protection - Lots keratin & oil -Erector Pilli ("goosebumps") -Stratum Corneum -Drugs change constitution of hair -Hair grows constantly

Lines of Cleavage

-Patterns due to gravity -Cutting along the lines=minimal scarring

Functions of Hair

-Protection -Heat retention -Prevents the loss of conducted heat from scalp to surrounding air -Facial expression -Sensory reception -Visual ID -Chemical signal dispersal

Functions of Skin

-Protection: physical barrier; can absorb certain chemicals and drugs (such as estrogen from a birth control patch or nicotine from a nicotine patch). The skin is said to be selectively permeable because some materials are able to pass through it, while others are effectively blocked. -Prevent water loss:The acidic nature of the barrier also prevents the invasion of certain bacteria -Temperture regulation: Blood vessels constrict when cold to slow blood flow. Contract when hot to dissipate heat -Metabolic regulation: The synthesis of vitamin D3 is important in regulating the levels of calcium and phosphate in the blood. -Immune defense: epidermal dendritic cells -Sensory reception: Merkel cells -Excretion: excretory function when it secretes substances from the body during sweating. Sweat contains waste and also helps cool the body down. Also contains sebaceous gland which lubricates skin and hair with sebum

Hair Color

-Result of the synthesis of melanin in the matrix adjacent to the papillae -Genetically determined -Environmental & hormonal factors (puberty) -Age (gray hair) 👵

The Integument

-Skin that covers your body -AKA Cutaneous membrane -Consists of skin, nails, hair, sweat glands, and sebaceous glands -Largest organ -Surface is covered by an Epi. that protects underlying body layers -CT contain blood vessels that provide nutrients -Smooth muscle controls blood vessel diameter & hair position -Nervous tissue monitors sensory receptors

Aging of Integument

-Skin will sag creating wrinkles -less immune cells -altered skin & hair pigmentation -sweat production diminishes -blood supply to the dermis is reduced leading to impaired thermoregulation (old people never get hot) & harder to repair wounds -hair thinning and loss -vitamin d diminishes (more fractures, brittle bones) -Skin cancer (lower immune system) most common cancer, greatest risk factor is exposure to UV rays in the sun; highest incidence unpeople with severe sunburns, especially children

Nails 💅

-Stratum corneum -Keratin -Protect exposed distal tips of digits

Dermis: Papillary Layer

-Superficial layer It is composed of areolar connective tissue, and it derives its name from the projections of the dermis toward the epidermis called dermal papillae (contains capillaries and sensory receptors) . The dermal papillae interlock with deep projections of epidermis called epidermal ridges.

Integument Repair & Regeneration

1. Cut blood vessels initiate bleeding into the wound. The blood brings clotting proteins, platelets, numerous whiteblood cells, and antibodies to the site. The clotting proteins and platelets stop the bleeding, while the white blood cells and antibodies clean the wound and fight any infection that may have been introduced. 2. A blood clot forms, temporarily patching the edges of the wound together and acting as a barrier to prevent the entry of pathogens into the body. Internal to the clot, macrophages and neutrophils (two types of leukocytes) clean the wound of cellular debris. 3. The cut blood vessels regenerate and grow in the wound. A soft mass deep in the wound becomes granulation (gran ́u ̄-l̄ ́shu ̆n) tissue, a vascular connective tissue that initially forms in a healing wound. Macrophages within the wound begin to remove the clotted blood. Fibroblasts produce new collagen in the region. 4. Regeneration of the epidermis occurs due to division of stratum basale cells at the edge of the wound. These newepithelial cells migrate over the wound, creeping internally to the now superficial remains of the clot (the scab). The connective tissue is replaced by fibrosis.

3 Layers

Epidermis Dermis Hypodermis

3 Kinds of Hair

Lanugo -Baby hair -Premature hair -Shed hair as you grow in placenta -Protects in womb Vellus -Hair on head & beards -No limit to length -Continuos growth -Lasts 7 years Terminal Hair -Grows to a certain length -controlled by genetics -Lasts for 3-4 months -eyebrows, body hair

Cells in Epidermis

Merkel Tactile Cells: detects pressure changes Epidermal Dendritic (Langerhans) Cells: immune cells, acid makes it hard for bacteria to grow on skin Melanocytes: Melanin is a pigment produced and stored in cells called melanocytes Keratinocytes: secretes keratin (oil/wax)

Skin Markings

Nevus (mole) Freckles Hemangioma -Capillary hemangiomas (strawberry colored birthmarks) -Cavernous hemangiomas (port-wine stains) can indicate brain damage.

Epidermis

SUPERFICIAL Stratum Corneum: all dead cells, squamous Stratum Lucidum: *found only thick skin*; found in areas with no hair (ex: soles, palms, lips, elbow) Stratum Granulosum: no longer mitotic; stays in G1 phase Stratum Spinosum: miotic; cuboidal/columnar (squished) Stratum Basale: deepest layer; miotic; cuboidal/columnar DEEPEST

cold sore

cold sore Small, fluid-filled blister that is sensitive and painful to the touch; associated with the lips and the mucosa of the oral cavity; caused by herpes simplex type 1 virus, which infects nerve cells that supply the skin. Also called a fever blister.

dandruff

dandruff Flaking of the epidermis of the scalp, resulting in white or gray scales in the hair.

eczema

eczema (ek ́z̆-m̆) Noncontagious skin inflammation often characterized by itchy, red vesicles that may be scaly or crusty.

hives

hives Eruption of reddish, raised areas on the skin, usually accompanied by extreme itching; causes include certain foods, specific drugs, or stress. Also called urticaria.

impetigo

impetigo (im-pe-tı ́ḡ) A contagious, pus-forming bacterial infection of the skin; fluid-filled vesicles form and then rupture, forming a yellow crust.

keloid

keloid (k̄ ́loyd) Excess scar tissue caused by collagen formation during healing; often painful and tender.

pruritis

pruritis (proo-rı ́tu ̆s) Irritating, itching condition of the skin that may be caused by infection or exposure to various irritants, such as chemicals, cleaning solutions, or mites.

psoriasis

psoriasis (s̄-rı ́̆-sis) Chronic inflammatory condition characterized by lesions with dry, silvery scales, usually on the scalp, elbows, and knees.

rosacea

rosacea (ro-z̄-she-uh) Chronic skin disorder that results in redness and small, red, pus-filled bumps or pustules, mainly on the face. The cause of rosacea remains unknown but evidence indicates heredity and environmental factors are to blame.

shingles

shingles A skin rash characterized by blisters on red base with burning pain. Caused by the varicella-zoster virus, which causes chickenpox. After someone has had chickenpox, the virus remains dormant in the body, associated with parts of the nervous system. Emotional stress, immune deficiency, or cancer can reactivate the virus to cause shingles (see Clinical View in chapter 16 for an expanded description of shingles).

wart

wart A growth of epidermal cells that forms a roughened projection from the surface of the skin; caused by human papillomavirus.

Types of Burns 🔥

🔥1st Degree: epidermis (ex: sunburn) 🔥🔥2nd Degree: epidermis, dermis (ex: sunburn w/ blister) 🔥🔥🔥3rd Degree: epidermis, dermis, hypodermis Tissue damage: tissue loss & fluid loss Skin grafting: get tissue from other places