Exam 3 Ch 5-6

Integumentary System consists of

Skin

Sudoriferous (sweat) glands

Sebaceous (oil) glands

Hairs

Nails

Subcutaneous tissue

skin consists of two layers

1. epidermis

2. dermis

3. hypodermis (not part of skin)

epidermis is the outermost layer of the skin, avascular, and consists of

epithelial tissue

dermis underlies the epidermis, vascular, and consists of

dense connective tissue

hypodermis or subcutaneous tissue is not part of the skin but still functions as ___ in the integumentary system

loosely anchors skin to muscles

shock absorption

insulation

epidermis consists mostly of

keratinized stratified squamous epithelium

types of cells that make up the epidermis

Keratinocytes

• protection

Melanocytes

• pigment- melanin

Dendritic cells

• macrophages- ingest foreign substances and activate immune system

Tactile epithelial cells

• sensory receptors

4-5 layers of epidermis (come lets get sun burnt)

Stratum basale

Stratum spinosum

Stratum granulosum

(Stratum lucidum)- palms/soles

Stratum corneum

cells above stratum granulosum are _____ while cells below are ____

dead, alive

dermis consists of what cell types

fibroblasts, macrophages, and occasionally mast cells and white blood cells

two layers of dermis

papillary dermis

reticular dermis

papillary dermis is the thin superficial layer of _____ consisting of loose, interlacing collagen and elastic fibers and blood vessels

areolar connective tissue

dermal papillae is the superficial region of dermis that sends fingerlike projections up into epidermis that contains

capillary loops, free nerve ending, and touch receptors

friction ridges (occur in thick skin are a collection of ridges formed by dermal papillae on top of dermal ridges) function as

enhance gripping ability

sense of touch-vibrations

reticular dermis consists of coarse _____ that provide stretch/recoil and strength and resilience

dense irregular connective tissue

dermal vascular plexus (reticular dermis)

network of blood vessels between reticular layer and subcutaneous tissue

cleavage tension lines (reticular dermis)

reticular layer are caused by many collagen fibers running parallel to skin surface

invisible

flexure lines (reticular dermis)

dermal folds at or near joints

(hands, wrists, joints)

Extreme stretching of skin can cause dermal tears, leaving silvery white scars called

striae

Acute, short-term traumas (e.g., burn or repeated friction) to skin can cause ___ , fluid-filled pockets that separate epidermal and dermal layers

blisters

what 3 pigments contribute to skin color

melanin carotene and hemoglobin

melanin is the only pigment made in skin by

melanocytes

two forms of melanin

reddish yellow or brownish black

excessive sun exposure can destroy ___ that causes alterations in D N A that may lead to skin cancer

folic acid (Necessary for DNA synthesis)

carotene has a yellow orange pigment most obvious in palms and soles because it accumulates in what tissues

stratum corneum and subcutaneous tissue

hemoglobin has what color

pinkish

What other factors cause alterations in skin color

Blueness, or cyanosis: Low oxygenation of hemoglobin; sign of respiratory or cardiovascular issues

Pallor, or blanching: Emotional stress, low blood pressure, anemia (decreased ability of blood to carry oxygen),

Redness, or erythema: Embarrassment, fever, inflammation, allergy

Yellowness, or jaundice: Liver disorders

Red/purple/green/yellow marks, or bruises, or ecchymoses, or hematomas: Result of blood leakage from damaged blood vessel beneath skin

Brown or black patches: Hyperpigmented, thickened skin in folds may be a sign of endocrine disorder

hair consists of

dead keratinized cells

what are the functions of hair

Sense insects on skin before bite or sting

Hair on head guards against physical trauma

Protect from heat loss

Shield skin from sunlight

Eyelashes shield eyes

Nose hairs filter particles from inhaled air

list two regions of hair

Root: portion within scalp, where keratinization is still going on

Shaft: portion that extends above scalp, where keratinization is complete

what are the 3 parts of the hair shaft

Medulla: central core of large cells and air spaces

Cortex: several layers of flattened cells surrounding medulla

Cuticle: outer layer consisting of overlapping layers of single cells

hair pigmentation is made by ___ in hair follicles

melanocytes

hair follicle

extends from epidermal surface to dermis (sometimes into subcutaneous tissue)

hair bulb

•Hair bulb: expanded area at deep end of follicle

hair follicle receptor

sensory nerve endings that wrap around bulb

wall of the hair follicle is composed of what

Peripheral connective tissue sheath, or fibrous sheath

• Derived from dermis, forms external layer of follicle wall

Glassy membrane

• Basement membrane of follicle epithelium

Epithelial root sheath

• Derived from epidermis, external root sheath and internal root sheath

•Papilla of a hair follicle, or hair papilla

–Dermal tissue containing a knot of capillaries that supplies nutrients to growing hair

if the papilla of a hair follicle is destroyed what happens

the follicle stops producing hair

hair matrix

•Hair matrix: actively dividing area of bulb that produces hair cells

–As matrix makes new cells, it pushes older ones upward

arrector pili

small band of smooth muscle attached to follicle

Responsible for “goose bumps”

name two types of hair

1. Vellus hair- pale, fine body hair of children and adult females

2. Terminal hair- coarse long hair

   1. scalp, eyebrows, face and neck of males, pubic regions

what affects hair growth

nutrition and hormones

follicles go through ___ between active and resting phases

growth cycles

hirsutism

condition in which females develop coarse, terminal hair in masculine distribution

by 60-65 years old most experience balding as terminal hair is replaced with

vellus hair

true balding is a pattern commonly found in

men

▪Hair follicles respond to androgens with decreasing growth cycles

Telogen effluvium

abrupt hair thinning caused by an abundance of hair follicles entering resting phase at same time

• caused by stress (hormonal changes with childbirth, surgery, severe emotional stress, or crash dieting) or low thyroid hormone levels, drugs, Severe dietary deficiencies of proteins or minerals

  
  

nails are scale-like modifications of epidermis that contain

hard keratin

nails act as

protective cover for distal, dorsal surface of fingers/toes

nails consist of

Root embedded in skin

Nail plate or body visible attached portion

Free edge

nail bed

•epidermis underneath keratinized nail plate

nail matrix

thickened portion of bed responsible for nail growth

nail folds

skin folds that overlap border of nail

cuticle or eponychium

nail fold that projects onto surface of nail body

hyponychium

area under free edge of plate that accumulates dirt

nails appear pink bec of

underlying capillaries

lunule

thickened nail matrix

yellow tinged nails indicate

respiratory or thyroid gland disorder

thickened yellow nails are caused by

fungal infection of nail

Koilonchya, also called “spoon nail,” is an outward concavity of nail may signal

iron deficiency

Beau’s lines are horizontal lines across nails may indicate

severe illnesses such as uncontrolled diabetes, heart attack, or cancer chemotherapy

sudoriferous glands help control

body temp

two types of sweat glands

Eccrine sweat glands- no odor

• Also called merocrine sweat glands

Apocrine sweat glands- odor

• Despite name, are merocrine glands

sweat glands contain what cells

•myoepithelial cells

eccrine glands location, function, secretion

Location: palms, soles, forehead

Function: thermoregulation

secretion: 99% water, salts, metabolic wastes (urea, uric acid, and ammonia), and dermcidin (microbe-killing peptide)

apocrine glands location, function, secretion

location: axillary and anogenital areas (armpit and genitals)

function: Function unknown but may act as sexual scent gland

secretion: viscous milky or yellowish sweat that contains fatty substances and proteins

• Bacteria break down sweat, leading to body odor

types of modified apocrine glands

Ceruminous glands and Mammary glands:

Ceruminous glands - modified apocrine glands

location: lining of external ear canal

secretion: cerumen - earwax

Mammary glands - modified apocrine glands

location: boob

secretion: secrete milk

sebaceous glands location, function, secretion

location: across body, develop from hair follicles

Function: producing and secreting sebum which protects from protects your skin from: friction, Moisture loss or brittle hair, Infections caused by bacteria or fungi

Secretion: Secrete sebum

• Oily secretion

• Bactericidal (bacteria-killing) properties

• Softens hair and skin

eccrine vs. apocrine vs. sebaceous glands

acne

an infectious inflammation of the sebaceous glands, resulting in pimples (pustules or cysts)

Whiteheads, or closed comedones,

blocked sebaceous glands

blackheads

If secretion is oxidized, whitehead becomes blackhead, or open comedones

Overactive sebaceous glands in infants can cause seborrhea

–Begins as pink, raised lesions on scalp that turn yellow/brown and slough off

what are the main functions of skin

Protection

Body temperature regulation

Cutaneous sensations

Metabolic functions

Blood reservoir

Excretion

protection - skin function

skin has 3 barriers:

• Chemical barriers: skin secretes chemicals (sweat and sebum), low pH, Melanin protects against UV

• Physical barriers: keratinized cells of stratum corneum block most water and water-soluble substances

• Biological barriers:

  • Dendritic cells (epidermis)- engulf foreign invaders and active immune system

  • Macrophages (dermis)- activate immune system

temperature regulation- skin function

insensible to sensible perspiration - more sweat produced to cool body

cold temp: –Dermal blood vessels constrict

insensible perspiration

Under normal, resting body temperature, sweat glands secrete about 500 m l/day of unnoticeable sweat

sensible perspiration

If body temperature rises, dilation of dermal vessels can increase sweat gland activity to produce 12 L (3 gallons) of noticeable sweat to cool the body

cutaneous sensations- skin function

part of nervous system

respond to stimuli outside of the body

metabolic functions- skin function

• Skin can synthesize vitamin D needed for calcium absorption in intestine

• Chemicals from keratinocytes can disarm some carcinogens

• Keratinocytes can activate some hormones

• Skin makes collagenase, which aids in natural turnover of collagen to prevent wrinkles

blood reservoir- skin function

Skin can hold up to 5% of the body’s total blood volume

Skin vessels can be constricted to shunt blood to other organs, such as an exercising muscle

excretion- skin function

Skin can secrete limited amounts of nitrogenous wastes, such as ammonia, urea, and uric acid

Sweating can cause salt and water loss

skin burns definition rule of nines complications

definition: tissue damage caused by heat, chemicals, electricity, radiation, or friction. Burns vary in severity based on depth and total body surface area (TBSA) involved.

rule of nines: a quick method used in emergency care to estimate what percentage of the body is burned and to estimate fluid loss

complications: infection, fluid loss, hypothermia, respiratory complications, scarring, organ dysfunction,

skin cancer definition rule of nines complications

basal cell carcinoma: Most common; least malignant; arises from stratum basale; pearly nodule; slow‑growing.

squamous cell carcinoma: Arises from stratum spinosum; scaly red papule; can metastasize.

malignant melanoma: Cancer of melanocytes; highly metastatic; dangerous; irregular dark lesion.

abcd rule: Asymmetry, Border irregularity, Color variation, Diameter > 6 mm.

skin burn severity

first: Epidermis only; red; painful; no blisters; heals without scarring.

second: Epidermis + dermis; blisters; very painful; moist; may scar.

third: Full thickness; charred/leathery; painless; requires grafting; severe scarring.