Post on 02-Jan-2016
HONORS ANATOMY & PHYSIOLOGYCHAPTER 5
HUMAN ANATOMY & PHYSIOLOGY
INTEGUMENTARY SYSTEM
Includes: Skin Nails Hair Sweat & Oil Glands
Integumentary System
FUNCTIONS
1. Protection: chemical barriers: skin secretions:
acidic: hostile to most bacteria some bactericidal melanin: chemical pigment shield protects
DNA from damage by UV rays physical barrier:
continuity of skin & hardness of keratinized cells
stratum corneum: multiple layers of dead cells (brick) and water-resistantglycolipids (mortar)
Substances that Penetrate Skin
1. lipid-soluble substances: )2, CO2, Vit A,D,E,K
2. oleoresins: poison ivy, poison oak3. organic solvents: acetone, dry-cleaning
fluid, paint thinner all dissolve cell lipids4. heavy metal salts: Pb, Hg5. selected drugs: nitroglycerine, nicotine,
fentanyl, seasickness meds, estrogen6. penetration enhancers: help carry other
drugs into body thru skin
Functions – Protection cont’d
3. Biological Barriers: dendritic cells of epidermis
active elements of immune system agn presenting cells
dermal macrophages phagocytes viruses or bacteria agn presenting cells
DNA e- can absorb some UV rays heat
body temperature homeostasis when body overheated blood flow to skin
increases & some heat radiates off body, sweating (sensible losses)
when body cold less blood flows to skin, more to trunk, goose bumps
@normal temps sweat glands lose ~500 mL/dthru insensible losses
Functions of Skin -2
Functions of Skin - 3
Cutaneous Sensation (sensory receptors): exteroceptors: sense stimuli from outside body Meissner’s corpuscles: in dermal papilla, feel
light touch Pacinian corpuscles: deep dermis or hypodermis,
feel deep touch hair follicle receptors: feel breezes, insect free nerve endings: pain from irritants or extreme
cold or heat
Functions of Skin - 4
Metabolic Functions: Sun light nrg powers some chemical reactions:1. modified cholesterol Vit D precursor 2. keratinocyte enzymes
“disarm” cancer-causing chemicals activate some steroid hormones (cortisone
cream cortisol a more potent anti-inflammatory)
3. synthesize important proteins collagenase
Functions of Skin - 5
Blood Reservoir dermal vessels can hold up to 5%of blood
vol. vessels constricted when
other organs need extra blood constriction shunts blood to areas in need
excretory function: sweat contains urea, uric acid (breakdown
products of proteins) NaCl + water lost with profuse sweating
Functions of Skin- 6
made of 2 kinds of tissues1. Epidermis2. Dermis
Structure of the Skin
made of stratified squamous epitheliumsome keratinized, some notavascularCells:
Keratinocytes majority of cells make keratin
Melanocytes Langerhans Cells
Immune System aka dendritic cells
Epidermis
Cells of the Epidermis
1. stratum basale deepest layer constantly undergoing cell division/ cells
pushed upward
2. stratum spinosum3. stratum granulosum4. stratum lucidum (only in thick skin)
clear, flatter, more keratin
5. stratum corneum (cornified = keratinized)
outermost layer/ 20-30 dead cells thick
Epidermal Layers
Layers of Epidermis
Thick Skin
areas subject to abrasion palms soles finger tips
Thin Skin
covers rest of bodythinnest skin (thinner subcutaneous
layer) eyelid: 0.02mm bridge of nose ankles knuckles
pigment (yellow to brown to black)
produced by melanocytes most are in stratum basale
cells stimulated to make more melanin when skin exposed to sunlight shields DNA from damaging effects of UV
radiationfreckles & moles: seen where melanin
concentrated in 1 spot
Melanin
a strong, stretchy envelope that helps to hold the body together leather is the dermis of whatever animal it was
made frommade of dense CT: strong& flexiblerich blood supply2 regions:1. Papillary2. Reticular
Dermis
upper dermisdermal papillae: uneven projections into
lower epidermis that contain:1. capillaries2. pain receptors3. touch receptors: Meissner’sCorpuscles4. in thick skin: form ridges (fingerprints)
that improve gripping ability genetically determined
Papillary Layer
deepest skin layerContains:1. sweat & oil glands, hair follicles, blood
vessels2. Pacinian corpuscles (deep touch
receptors)3. many phagocytes4. fibers: elastic: give young skin elasticity collagen: make dermis tough &
keeps skin hydrated by binding to water
Dermis: Reticular Layer
Dermis
Striae
extreme stretching of skin white scarsaka stretch marks
3 pigments contribute to skin color:1. Melanin
amount & kind (yellow black)
2. Carotene orange – yellow pigment stratum corneum & subcutaneous layers
3. Hemoglobin amount O2 bound to it in RBCs in dermal blood
vessels has greater affect in light skinned people
Skin Color
cyanosis: blue hue to skin; due to poorly oxygenated blood
erythema: redness, due to increased blood flow (infection, inflammation); burn, HT, blushing
pallor: paleness, due to emotions, anemia, low BP, decreased blood flow
jaundice: yellow; usually from liver disease (not clearing bilirubin)
hematomas: bruising (bleeding under skin)
Skin Color in Sickness & in Health
Appendages of the Skin
derivatives of epidermis: hair& hair follicles nails sweat glands sebaceous glands
Hair & Hair Follicles
areas of skin with no hair: palms soles lips nipples parts of external genitalia
Functions of Hair
sense insects b/4 they biteprotects against heat loss (scalp)protects against sunshield eyesfilter air inhaled through nose
Hair
“pili”produced by hair folliclesconsist of dead keratinized cellskeratin here compared to keratin in epidermis:
tougher & more durable individual cells do not flake off
Hair
3 concentric layers of keratinized cells1. Medulla
innermost large cells & air space absent in fine hair
2. Cortex surrounds medulla layers of flattened cells
3. Cuticle 1 layer overlapping cells provides strength
Hair Pigment
melanocytes @ base of follicle to cortical cells
differing proportions of melanins of different colors give different hair colors
melanin production decreases (delayed-action genes) replaced by air bubbles gray white
Hair Follicle
fold down from epidermis dermis forming hair bulb
sensory nerve ending : root hair plexus surrounds hair bulb bending hair
stimulates plexus sensitive touch
receptors
Hair Follicle
dermal papilla: bit of dermal tissue protruding into base of follicle capillaries
matrix: actively dividing cells produces hair
arrector pili: smooth muscle from dermal part of follicle epidermis @ angle contraction goose
bumps
VELLUS TERMINAL
pale, fine hair children and
females
coarse long hairseyebrows, scalp@ puberty:
Types of Hair
Factors the Influence Hair Growth
1. Nutrition poor nutrition
poor growth2. Hormones 3. local inflammation
increased growth
normal growth~2.5 mm/wk
fastest growth teens 40’s then slows
each follicle goes thru cycle:
1. active growth phase wks yrs
2. regressive phase matrix cells die
3. resting phase 1 – 3 mos
Hirsutism
excessive hairinesscould be from ovarian
or adrenal gland tumor secreting high levels of androgens
Alopecia
hair thinningstarts @ anterior
hairline posteriorlymales:
by age 35: 40% by age 60: 85%
Male Pattern Baldness
most common type of baldness
X-linked recessive inheritance: delayed-action gene
switches on in adult & changes hair follicle response to testosterone follicles very short growth cycle may get vellus hair
Alopecia Areata
immune system attacks hair follicleshair falls out in patches
Nails
scalelike modification of epidermis forming clear protective covering on dorsal
surface of distal digitshard keratinFunctions:1. pick up small objects2. scratch3. protect tips of digits
Parts of a Nail
1. free edge2. nail plate or body3. nail bed
proximal portion = matrix: nail growth
4. proximal root5. nail folds:
proximally :eponychium (cuticle)
Nail Abnormalities
yellow: thyroid or respiratory problem
thickened yellow: fungus infection
outward concavity: iron deficiency (spoon nail)
horizontal lines: malnutrition
Sweat Glands
aka sudoriferous glands
over entire skin surface except: nipples parts of external
genitalia2 types:1. Eccrine Sweat
Glands2. Apocrine Sweat
Glands
secretory cells surrounded by myoepithelial cells: contract when stimulated by nervous system sweat goes thru duct to skin
Eccrine Sweat Glands
more numerous than apocrine
abundant on palms & soles of feet
secretory cells in dermis
sweat released thru pore (not skin pore)
Eccrine Sweat Gland
secretion: hypotonic (99% water) filtrate of blood
also has: salts vitamin C abys wastes: urea, uric
acid, NH3
Eccrine Sweat Gland
regulated by sympathetic division of ANSFunctions:1. prevent overheating
forehead spreads inferiorly
2. “emotional” sweating fright or extreme nervousness palms, soles, or axilla over body
Apocrine SweatGlands
axillary & anogenital areas onlylarger than eccrine glandsfound deeper in dermis/hypoderrmisempty onto hair follicleodorless until released onto skinwhere
bacteria decompose molecules musky, unpleasant odor
in addition to what is found in eccrine sweat: fatty acids proteins
Apocrine Sweat Glands
begin functioning @ pubertyactivated by sympathetic division of ANS
during: pain stress
exact function uncertain but likely analogous to animals glands that secrete pheromones
Ceruminous Glands
modified apocrine glands
secretion mixes with sebum (made by sebaceous gland) cerumen (ear wax)
Function:deters insects blocks entry of
foreign objects
Mammary Glands
specialized sweat glands that secrete milk
Sebaceous Glands
oil glandsfound with hair follicles
smaller on trunk & limbs large on face, neck, upper chest
secrete sebum: oily substance develop as outgrowths of hair folliclearrector pili contractions force sebum to skin
surfaceandrogens stimulate secretion (activity starts
in puberty)
Sebum
Functions:1. softens & lubricates skin & hair2. bactericidal action
Whitehead Blackhead
created by: sebum blocks
sebaceous gland duct
sebum in whitehead oxidizes
Acne
active inflammation of sebaceous glands
see: pustules or cysts on skin surface
associated with bacterial infection (staph)
Skin Cancer
Benign tumors such as warts and moles are not serious.
Malignant tumors can start on the skin and invade other body areas.
Crucial risk factor- overexposure to UV radiation
Skin Cancer
20% in USA will develop skin cancer (↑ing #s)#1 risk factor: Sun UV radiation
DNA damaged suppresses tumor suppressor gene new skin lotions contain liposomes initiate
repairof damaged DNA
Types of Skin Cancer
Basal cell carcinoma- most common, 30% of all white skin people get it. Arises from the stratum basale layer of the skin 99% curable if caught early Dome shaped nodules that form an ulcer in the
center.Squamous Cell carcinoma-
Arise from stratum spinosum Grows rapidly and metastasizes if not removed Small red rounded elevation on the skin
Basal Cell Carcinoma
Lesion removed from patient
Basal Cell Carcinoma
Squamous cell carcinoma
Skin Cancer Types cont.
Melanoma Cancer of melanocytes (very dangerous) 5% of skin cancers but rising fast Can arise from preexisting moles Appears as a spreading brown or black patch Chance of survival is poor if the lesion is greater than
4 mm thick
Melanoma
What is the ABCD rule?
Used for recognizing melanomaA-Asymmetry: two sides of the pigmented
mole do not matchB-Border irregularity: borders are not smoothC- Color: lesion has a multiple of colorsD- Diameter the spot is larger than 6 mm in
diameter (size of a pencil eraser)
What are the 3 types of burns?
First-degree burns: only the epidermis is damaged. Redness, swelling and pain are common. (sunburn) 2-3 days to heal
Second-degree burns: epidermis and upper layers of dermis. Blistering can occur. 3-4 weeks to heal.
Third-degree burns: involves the entire thickness of the skin. (pg. 164-165)
Third-degree burn
Second-degree burns
Burn Evaluation
Rule of 9’s:divides body into11areas each 9% of body
surface area + 1% for genitalia
Burn Treatment
patients require extra calories to replace lost proteins & allow tissue repair must add parenteral nutrition (IV)
2◦ infections main threat 24 hrs after burn wound is sterile fungi, bacteria,& other pathogens multiply
rapidly Immune system deficient infection leading cause of death in burn victims
Burn Treatment: Skin Grafts
1st debride burned tissuewash area with antibiotic in solutionapply synthetic membrane temporarilyskin graft: healthy skin applied to area
autograft: taken from the patient synthetic skin: silicone “epidermis” bound to
spongy “dermis” made of collagen fibers & ground cartilage patients own cells absorb &replace synthetic
* no rejection from immune system
Think About It