Anatomy and Physiology Exam 2

Exam 2

integumentary system consists of:

skin, hair, nails, sweat glands, sebaceous glands

skin regions

epidermis, dermis, hypodermis

epidermis

superficial skin region

epithelial tissue- primarily keratinized stratified squamous

withstand high wear and tear

avascular

dermis

areolar and dense connective tissues

vascular

under epidermis

hypodermis

mostly adipose tissue

absorbs shock, insulates body, anchors skin to muscles

subcutaneous layer deep to skin

keratinocytes

produce keratin which gives skin its protective properties

millions slough off making household dust

in epidermis

melanocytes

produce pigment called melanin

protects cell nucleus from UV damage

located deep within epidermis

dendritic cells

start shaped macrophages

key activators of immune response

in epidermis

merkel cells

sensory receptors for touch

in epidermis

epidermal layers(from deep to superficial)

stratum basale

stratum spinosum

stratum granulosum

stratum lucidum(thick skin only)

stratum corneum

stratum lucidum

epidermal layer for thick skin only

high wear areas

palms and soles

clear layer

thin, translucent band of 2-3 layers of flat, dead keratinocytes

stratum basale

aka stratum germinativum

deepest layer of epidermis

firmly attached to dermis

single row of actively dividing stem cells

cells die as they move toward surface

sratum spinosum

prickly layer

2nd deepest layer of epidermis

several layers thick

web-like system of pre-keratin filaments

resists tension and pulling

dendritic cells and melanosomes abundantly scattered throughout

stratum granulosum

3rd epidermal layer

1-5 layers of flat cells

cell appearance begins to change

nuclei and organelles disintegrate

keratinization begins

cells above this layer begin to die- too far from dermal caplillaries

stratum corneum

outermost epidermal layer

20-30 layers of flat, keratinized dead cells

75% of epidermal thickness

protects deeper layers from environment

prevent water loss

dermis

made from strong, flexible connective tissue

contains semifluid matrix, nerves, blood/lymph vessels, hair follicles, sweat and sebaceous glands

papillary and reticular layers

papillary layer

superficial layer of dermis

loose areolar connective tissue

contains collagen, elastic fibers, blood vessels

dermal papillae-projections into epidermis

dermal papillae

finger-like projections into epidermis

capillaries

free nerve endings(nociceptors = pain)

touch receptors(meissners’s corpuscles)

nociceptors

pain

free nerve endings

often trigger a withdrawal reflec

meissner’s corpuscles

light touch receptors

sense of texture

caress, brush

reticular layer

deeper layer of dermis

dense irregular fibrous connective tissue

elastic and collagen fibers for stretch and strength

80% of dermal thickness

striae

stretch marks

dermal tears leave silvery white scars

pregnancy or rapid gain in body size

blisters

fluid filled pockets separating dermal and epidermal layers

caused by acute, short term trauma to skin

burns or friction

photosensitivity

increased reactivity to sun exposure

caused by drugs, perfumes

leads to skin rashes

melanin

only pigment made in skin

shields DNA of keratinocytes from damaging UV

more sun protection needed = greater production

carotene

yellow-orange pigment(palms and soles)

can be converted to vitamin A for vision and epidermal health

hemoglobin

provides pinkish hue for fairer skins

cyanosis

skin turns blue

indicates low oxygenation of hemoglobin

pallor

blanching/pale

due to anemia, low blood pressure, fear, anger

erythema

redness

due to fever, hypertension, inflammation, allergy

jaundice

yellow

indicated liver dysfunction/failure

vitiligo

chronic autoimmune disorder causing patches of skin to lose color

destruction of melanocytes, no pigment, skin has white patches

patches usually appear symmetrically

functions of the hair

warn against insects(or foreign bodies) on skin

guard against physical trauma(head)

protect from excessive heat loss

shield skin from sunlight

Hair cover the body except

palms

soles

lips

nipples

portions of external genitalia

hair bulb

expanded area at deep end of hair follicle

has the hair matrix

hair matrix

actively dividing area of bulb

hair growth

hair follicle receptor

sensory nerve endings encasing bulb

hair is a touch receptor

arrector pili

small band of muscle attached to follicle

causes goosebumps and hair standing sensations

hair color

pigment is causes by melanocytes in follicles

different combinations of melanin give color

pheomelanin

additional pigment in red hair

lanugo

soft, unpigmented hairs

fetuses/newborns

vellus hair

pale and fine

peach-fuzzy

body hair on children and adult females

terminal hairs

coarse and long, pigmented

scalp and eyebrows

after puberty axillary, pubic, face, and neck

alopecia

some degree of hair loss

alopecia areata

portion of single body part

alopecia totalis

entire portion of single body part

alopecia universalis

entire body

androgenic alopecia

gene/hormone related

tellugen effluvium

caused by thyroid disorder, stress, diet

anagen effluvium

caused by chemotherapy

traction alopecia

caused by hair consistently being pulled back tight

ex. military, dance, cheer, gymnastics

nails

modifications of the epidermis

contain hard keratin

act as protective covers for distal, dorsal surface of fingers and toes

free edge

what hangs past distal end of finger/toe

keratinized

nail plate

sits over distal surface of finger/toe

keratinized

nail root

proximal to cuticle

embedded in skin

nail bed

rests deeply covering epidermis

under nail plate

nail matrix

portion of nail bed responsible for nail growth

fungal infection

thick, yellow nails

koilonchya

“spoon nail”

nail becomes outwardly concave

indicates iron deficiency(can lead to anemia)

beau’s lines

horizontal lines across nails

can indicate severe illness(diabetes, heart attack, cancer)

clubbing

nails appear convex, club like

can indicate respiratory and cardiovascular diseases

sweat glands(sudoriferous glands)

on all skin surfaces except nipples and external genitalia

exocytise hypotonic solution of 99% water, 1% NaCl

2 types: eccrine(merocrine) and apocrine(post puberty)

eccrine(merocrine) glands

most abundant sweat glands

especially on palms, soles, and forehead

ducts empty to pores

thermoregulation

apocrine

post puberty sweat glands

only in axillary and anogenital areas

larger sweat glands

ducts empty into hair follicles

secretes viscous, milky/yellow sweat containing fatty substances and proteins

superficial bacteria break this down causing body odor

sebaceous(oil glands)

widely distributed(except thick skin)

most develop from from follicles and secrete into hair follicles

stimulated by hormones

arrector pili contractions push out sebum

acne results from infectious inflammation of glands

holocrine glands

sebaceous(oil) glands

accumulate products within until it bursts forth

sebum

oily secretion in sebaceous glands

bactericidal(bacteria-killing)

softens hair and skin by preventing excess water loss

whitehead

blocked gland

blackhead

secretion oxidized in pimple

skin barriers for protection

chemical: sweat, sebum, low pH, melanin, defensin

physical: cells are keratinized

biological: dendritic cells in epidermis, macrophages in dermis, DNA absorbs UV

main functions of skin

protection

thermoregulation

cutaneous sensation

metabolism

blood reservoir

waste excretion

insensible perspiration

unnoticed, evaporates quickly, no beads

normal, resting body temperature: 500 mL/d

sensible perspiration

very noticeable, beads and drips

when body temperatures rises

dermal vessels dilate

cutaneous sensation

exterocepters on skin respond to stimuli outside body(environment)

touch, temperature

function of skin

pacinian corpuscles

coarse touch receptors

give sense of shape

bumps, ridges

metabolic skin function

skin synthesizes vitamin D via sunlight exposure

necessary fro calcium absorption in intestines

blood reservoir

skin function

skin holds up to 5% of total blood volume

dermal vessels can constrict and shunt blood elsewhere when needed

excretion

skin function

skin can secrete some nitrogenous wastes

sweating causes water and salt loss

skin cancer

most skin tumors are benign(non-cancerous) and don’t spread(metastasize)

risk increases with overexposure to UV radiation

some lotions contain enzymes to help repair damaged DNA

basal cell carcinoma

most common, least malignant skin cancer

stratum basale epidermal cells proliferate and slowly invade deeper skin layers

99% cured with simple excision

squamous cell carcinoma

not very malignant but can metastasize

good prognosis if treated early

involves keratinocytes of stratum spinosum

appears as a red papule or splotch on scalp, ears, lower lip, hands

melanoma

highly malignant and metastatic

resistant to chemotherapy

cancer of melanocytes

early detection is key

ABCD rule

asymmetry, border, color, diameter

burns

tissue damage(protein denaturation via:

heat, chemicals, electricity, radiation

damaged/lysed cells lose ICF

can lead to dehydration and electrolyte imbalance

in severe cases renal failure or shock

rule of nines

how burns are evaluated

body is divided into 11 sections

each section is 9% of body surface

except genitals is 1%

estimate volume of fluid loss

first degree burns

epidermal damage only

localized redness, edema(swelling), pain

second degree burn

epidermis and upper(superficial) dermis damaged

blistering

partial thickness burns

first and second degree burns

third degree burns

full thickness burn

skin turns gray-white, cherry red, or black

no edema

no pain - nerve endings destroyed

skin grafting necessary

critical burns

more than 25% of body has 2nd degree burns

more than 10% of body has 3rd degree burns

face, hands, or feet have 3rd degree burns

skin development

skin thickens

more subcutaneous fat forms

sweat and sebaceous gland activity increases

signs of aging can be delayed by:

UV protection

nutrition

hydration

hygiene and skincare

genetics

function of bones

support for body and soft organs

protection for CNS and vital organs

movement via joint articulations and muscle insertions

mineral storage for calcium and phosphorous

blood cell formation in bone marrow

triglyceride storage for energy

axial skeleton

skull, vertebral column, rib cage

appendicular skeleton

bones of the limbs

girdles attach limbs to the axial skeleton

long bones

longer than they are wide

limbs

short bones

cube shaped

wrist and ankle

sesamoid bones

form within tendons

patella

flat bones

thin, flat, slightly curved

sternum, scapulae, ribs, cranial bones

irregular bones

weird shapes

vertebrae

compact bone

dense, outer layer on every bone

smooth and solid

consists of osteons and canals