Human Anatomy & Physiology

Chapter 4-SKIN & BODY MEMBRANES notes

  • ______cover surfaces,line body cavities and forms protective-sometimes lubricating –sheets around organs

I.  Classification of Body Membranes

A.  EPITHELIAL MEMBRANES

  • Covering and lining membranes
  • All have an underlying sheet of connective tissue

1.  Cutaneous Membranes= skin

§  Superficial epidermis is______

§  Underlying dermis is dense(fibrous) connective tissue.The superficial tissue is exposed to air and is a ______

2.  Mucous Membranes-made of varying types of epithelial tissue resting on a loose connective tissue called ______and lines all membranes that open to the exterior(hallow organs of respiratory tract,digestive,urinary and reproductive…

§  Mucosa refers to location,not cellular makeup….But most mucosa are stratified squamous (mouth and esophagus) epithelium or simple columnar (rest of digestive tract)----all wet and bathed in secretions)

3.  Serous membranes(serosa)-

§  Has a layer of simple squamous epithelium on a thin layer of ______

§  Serosa are closed to the exterior(except for dorsal body cavities and joint cavities)

§  Occur in pairs…The ______lines a specific portion of the ventral body cavity

§  Parietal layer folds in itself to form ______-covers outside of the organs in that cavity

§  Serous layers separated by______-secreted by both membranes

®  Serous fluid allows organs to slide against ea. other and cavity w/o friction

®  SEROUS NAMES RELATED TO LOCATION

®  ______covers abdominal cavity

®  ______-surrounds lungs

®  ______surrounds heart

B.Connective Tissue membranes

  • Composed of ______and has NO epithelial cells-line capsules surrounding joints
  • Line small sacs of connective tissue called bursae and the tubelike tendon sheath----all cushioning organs against each other and tendon across bone

II.The Integumentary Sysyem(skin)-cutaneous membrane

A.  functions –most importantly protective….against mechanical damage,chemical damage,

bacterial damage,

UV effects,thermal effects and dessication(drying out)

---also aids in controlling body heat

---aids in excretion of urea and uric acid

----synthesizes Vitamin D

  • The uppermost layer is full of ______-and is cornified or hardened-help prevent water loss
  • Capillaries and sweat glands work on thermal control
  • ______sense

touch,pressure,temperature and pain

B.  Structure of skin

  • Epidermis-stratified squamous epithelial capable of keratinizing(hardening
  • ______-underneath-mostly dense connective tissue
  • Epidermis and dermis strongly connected,but some abuse can cause them to separate—interstitial fluid comes between layers making a ______
  • ______is below dermis and mostly adipose----not actually considered part of skin,but attaches skin to organs beneath---works as “shock absorber” and insulates from extreme temperatures

1.  Epidermis-

§  has 5 layers or ______.From inside out they are stratum basale, spinosum ,granulosum, lucidum and corneum

§  avascular

§  most cells are ______which make keratin

§  Stratum basale-closest to dermis and connected along a wavy borderline.Contains epidermal cells that that get the most nourishment by diffusion from dermis;constant cell division-MILLIONS OF NEW CELLS DAILY(also called stratum germanitivum),daughter cells pushed upward

§  Stratum Spinosum and stratum granulosum become flatter and increasingly full of keratin

§  When the previous cells die,they form the clear ______-not in all skin regions-only where skin is hairless and extra thick-ie.palms and soles;it secretes a water repellent glycolipid into extracellular space;distant from blood supply,so little nutrients-doomed cells

§  OUTERMOST Stratum corneum—20-30 cells layers thick and is ¾ of epidermal thickness;cornified,shinglelike dead cells,filled w/ keratin;protects lower cells;dandruff sloughs off from here

§  We have a totally new epidermis every 25-45 days

§  ______pigment that ranges in color from yellow to brown to black produced by melanocytes(in stratum basale).When skin is exposed to sun,this stimulates these cells to make more of the pigment---THUS tanning

§  Melanin accumulates in membrane bound granules called ______.They move to the end of the melanocytes and taken up by keratinocytes .THERE,melanin forms a pigment umbrella over superficial side of nuclei-shielding DNA from UV

§  ______and moles are where melanin are concentrated in one spot

2.  dermis-‘hide”

  • strong,stretchy
  • dense fibrous connective tissue

1.  ______upper dermal region;______-peglike projections from superior surface-many containing capillary loops-thus nutrients;some have pain receptors-______or touch receptors-______

  • Has whorled rings on soles and palms,increasing friction and gripping ability----genetically determined…..sweat pores provide for fingerprints

2.  ______deepest skin layer w/blood vessels,sweat and oil glands and ______deep pressure receptors;phagocytes act here at reticular layer

o  Collagen and elastic fibers found in dermis.collagen gives toughness and attract water for hydration.Elasisic fibers give elasticity that declines w/age

o  Many blood vessels help w/ body temp.,homeostasis.skin is red when hot due to engorging of blood

o  ______happen in bedridden patients not turned regularly -pressure restricts blood supply and redness when pressure is released

o  Rich nerve supply

C.  Skin Color-3 pigments:

1.  melanin in epidermis

2.  carotene in stratum corneum and subcutaneous tissue

3.  O2-rich hemoglobin in dermis

----varying amounts of the above create the numerous skin colors.Which is showing up more in Caucasians?______

§  ______hemoglobin is poorly oxygenated---can happen during heart failure and severe bleeding

  • What else affects skin color?:

Emotions and various disease states:

  1. ______-redness-blushing, hypertension, inflammation ,allergy
  2. ______-blanching-pale—fear ,anger also anemia ,low blood pressure ,impaired blood flow
  3. ______-yellowness-liver disorder
  4. ______-sites where blood has escaped and clotted in tissue spaces;can happen w/disease or vitamin C deficiency
  5. ______-clotted blood mass

D.  Appendages of the Skin

1.  ______-exocrine glands-release secretions to skin’s surface via ducts

a)Sebaceous glands-oil glands-excepts on palms and soles—some open into hair follicle and some to surface

______-is product-clump of oil and cells;keeps skin moist and prevents hair from drying out

2.  ______(sudoriferous glands)-many in the skin-2 types:1)eccrine glands-all over body and make sweat(mostly water,NaCl,vitamin C and traces of metabolic wastes(ammonia, urea,uric acid and lactic acid.It is acidic and inhibits bacteria….sweat comes through a pore(not same as facial pores);helps regulate temp.(37 C)

2)______-mostly at axillary and genital areas;ducts empty into hair follicles;contains fatty acids and proteins—giving milky/yellowish color.It is odorless,but that changes when bacteria use it as food:function at onset of puberty regulated by androgens(male sex hormones----have been connected to sexual foreplay

3. Hair and Hair Follicles

§  1)Hairs made by hair follicles and is flexible epithelial structure;root in ______and shaft protrudes It is formed by mitosis of stratum basale epithelial cells in matrix(growth zone)-become keratinized and die as pushed forward---mostly hair contains protein

§  Hair has central core called a medulla surrounded by a cortex.This is covered by a cuticle(most keratinized region)-gives strength

§  Hair pigments made by melanocytes in hair bulb

§  Variety of shapes and sizes(eyebrows v. head then skin hair).If shaft is flat and ribbonlike-hair curly or kinky.If shaft is round-straight or coarse hair

§  Hair all over except soles,palms,nipples and lips

§  Fastest growing tissue in body

§  Have hormonal control

§  2) hair follicles-contain inner epidermal sheath that forms hair/outer dermal sheath is connective tissue/papilla yield blood supply to matrix in hair bulb

§  ______smooth muscle that raise hair in resonse to temp

§  3) Nails-scalelike product of dermis(corresponds to hoof or nail)

§  Each nail has a ______,a body(visible and a root(imbedded in skin)

§  Nail bed in stratum basale and inner ______,responsible for growth-cells become keratinized and die

§  Part appears pink due to vascularization in dermis

§  ______appears white

E.  Homeostatic imbalances of skin

1.  Infections and Allergies

  • ______-fungal,itchy red ,peeling skin(tinea pedis)
  • Boils and Carbuncles-inflammation of hair follicles and sebaceous glands—often dorsal neck.Carbuncles are caused by bacteria-esp. Staphylococcus aureus
  • ______-small fluid filled(fever blisters)-itch and sting –caused by a herpes simplex virus-can be activated from dormancy from emotions,fever,UV light-usually around lips or oral mucosa
  • ______-itchy,red,swelling and turns into blisters-exposure to chemicals like poison ivy
  • ______-pink,water-filled raised lesions around nose and mouth;w/yellow crust;caused by Staphylococcus
  • ______-chronic overproduction of cells w/ red epidermal lesions—probably autoimmune

2.  burns-tissue damage and cell death caused intense heat,electricity,UV light or certain chemicals---This can have a domino effect on several organ systems

  • destroys cells
  • Life threatening from 1) loss of fluids as they seep from burned surface-dehydrating and fluid imbance-could shut down kidneys and cause circulatory shock
  • ______-divides body into 11 areas,ea. 9% of total body surface area+ area around genitals-determines 5 burned
  • 2) infection later is a leading cause of death-after 24 hrs.,pathogens invade the area and multiply quickly
  • Classification:
  • 1st degree-only epidermis is damaged-red and swollen
  • 2nd degree injury to epidermis and upper dermis-regrowth will occur
  • 1st and 2nd degree are ______burns
  • 3rd degree-destroys entire thickness of skin(full-thickness burns)
  • Critical if a) over 25% covered w/ 2nd degree b) over 10% 3rd degree OR c) 3rd on face ,hands or feet

BURNS

3.  Skin Cancer-

o  Most neoplasms benign(ex-wart)

o  Affect 1/5 americans

o  ______-least malignant and most common-affects stratum basal so cannot form keratin;boundary between epidermis and dermis lost;fairly slow growing

o  ______-from stratum spinosum-scalp,ears,hands-grows rapidly,but if caught early,prognosis is good

o  ______-cancer of melanocytes(5%of skin cancers)-happen where ever there is pigment and often deadly-50% survival w/early detection

o  ABCD RULE_

a)asymmetry

b)border irregularity

c)color-areas of different color

d)diameter-larger than 6 mm

III. Take notes p. 127 on developmental aspects:

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