Bio 210 lecture exam 2

Integumentary system

consist of skin and its derivatives

The integument

is the skin covering the body

the integument

also known as the cutaneous membrane

Dermatology

its scientific study and treatment of the integumentary system

The integument

the body's largest organ

Layers of the skin

epidermis, dermis, subcutaneous layer(not considered in the integument)

Epidermis

stratified squamous epithelium

Dermis

deep layer, primarily dense irregular connective tissue

Subcutaneous layer

deep to dermis, Layer of areolar and other connective tissue, hypodermis or superficial fascia, Not part of the integument(true skin) but is still part of integumentary system

Thick skin

on the palms of hands, soles of feet and surfaces of fingers and toes, All five layers of the epidermal strata, Has sweat glands

thick skin

has no hair follicles or sebaceous glands

Thin skin

lacks a stratum lucidum, has sweat glands, hair follicles and sebaceous glands

Hemoglobin

an oxygen binding compound, Bright red color upon binding oxygen, More visible when blood vessels dilate

Melanin

black, brown, tan, yellow-brown shades

Melanocytes

pigment of melanin is produced and stored here

UV light

stimulating melanin production

melanin

darker skinned producing more and dark colored

Carotene

yellow, orange pigment, acquired from yellow-orange vegetables, converted to vitamin A within the body

Nevus

a mole, harmless overgrowth of melanin forming cells

Freckle

yellowish brown spots, represent localized areas of increased melanocyte activity

Hemangioma

skin discoloration due to benign blood vessel tumor

Capillary hemangiomas

usually present at birth and disappear in childhood, strawberry colored birthmarks

Cavernous hemangiomas

may last a lifetime, port-wine stains

Friction ridges

complex arches and whorls on finger, palms, soles, and toes, formed from large folds and valleys of the dermis and epidermis, interlocking of epidermal ridges and dermal papilla, help increase fiction on contact, each individual with unique pattern of these

Dermis

deep to the epidermis, composed of connective tissue

Two layersof the dermis

papillary and reticular layer

Lines of cleavage, stretch marks, and wrinkles

collagen and elastic fibers oriented in parallel bundles

Incisions parallel for surgery

more likely to heal quickly, scarring reduced

Incisions perpendicular to cleavage lines for surgery

more likely to open due to cut elastic fibers, scarring increases

Stretch marks

striae

Dermal blood vessels

supply nutrients to epidermis and dermis, play an important role in body temperature and blood pressure regulation

Vasoconstriction

blood vessel diameters narrowed, look pale when exposed to cold

Vasodilation

blood vessel diameter increased, occurs when needing to loose heat, why people become flushed during exercise

Subcutaneous layer

not considered part of the integument, not the true skin, the layer underneath the skin

Functions of the subcutaneous layer

acts as energy reservoir, provides thermal insulation, drugs often inject here

Epidermal derivatives

nails, hair, exocrine glands derived from epidermal epithelium

Hair is found almost everywhere on the body besides

the hands and palmar surface of fingers, the siders and soles of the feet and toes, the lips, portions of the external genital

Three types of hair

lanugo, vellus, terminal

Lanugo hair

fine, un-pigmented, downy hair

Vellus hair

fine hair, primary human hair, found on upper and lower limbs

Terminal hair

coarser, pigmented, longer, on scalp, eyebrows, and eyelashes, men's beards, during puberty replaces vellus hair in axillary and public regions

Functions of the hair

protection, heat retention, sensory reception, visual identification, chemical signal dispersal

Disperse pheromones

chemical signals involved in attracting sexual partners

Hair color

results from synthesis of melanin in the matrix adjacent to hair, reflects genetic, environmental and hormonal factors, becomes lighter with age as pigment production decreases

Growth rate of hair

one-third mm per day in the scalp for 2 to 5 years, enters formant phase of 3 to 4 months, eventually pushed out and replaced by new hair

Hair loss

normal scalp to loss of 10-100 hairs per day

Alopecia

thinning of hair, usually result of aging

Two most common types of exocrine glands

sweat glands and sebaceous glands

Sweat glands

Merocrine and apocrine glands

Merocrine

most numerous and widely distributed sweat glands, secrete sweat

sensible perspiration

sweating and knowing you are

Insensible perspiration

involuntary, the loss of fluid by evaporation through the stratum corneum

Major function of thermoregulation

produce exocytosis

Apocrine sweat glands

discharge their secretions into hair follicles, found in axillae, around nipples, in pubic and anal region, produce odor when acted on by bacteria

Sebaceous glands

produce oily secretion called sebum

Holocrine glands

activated during puberty

Ceruminous glands

located only in the external acoustic auditory canal, produce cerumen (earwax)

Earwax

cerumen

Mammary glands

produce milk, apocrine glands of the breast

Epidermis functions

acts as a physical barrier, prevention of water loss,

Metabolic regulation of vitamin D

also termed cholecalciferol, transported to kidney and converted to calcitriol

Metabolic regulation of calcitriol

the active form of vitamin D, increased absorption of calcium and phosphate, important in regulating blood levels of calcium and phosphate, synthesized in the kidneys

UV rays

cause melanocytes to produce melanin

Secretion

waste products secreted onto skin surface during sweating

Electrolytes

prevent dehydration

Absorption

selectively permeable

Transdermal administration

some oil soluble drugs delivered by adhesive patch

Dendritic cells

within the stratum spinosum of the epidermis, initiate immune response against pathogens

Dermis functions

temperature regulation, sensory reception

Regeneration

replacement of damaged cells with same cell type, restores organ function

Fibrosis

gap filled with scar tissue, collagen fibers build, you get a scar

Stages of wound healing

1. Cut blood vessels bleed into wound 2. Blood clot forms and leukocytes clean wound 3. blood vessels regrown and granulation tissue forms 4. epithelium regenerates and connective tissue fibrosis occurs

first degree burns

only involved epidermis, slight redness and pain, immerse burned area in cool water

second degree burn

involve epidermis and part of dermis, skin blistered and painful, slight scarring

third degree burn

involve epidermis, dermis, and subcutaneous layer, require hospitalization

rule of nines

test the severity of the burn

skin changes with aging

decrease collagen fibers

basal cell carcinoma

most common type of skin cancer, does not spread

squamous cell carcinoma

may spread, arises from keratinocytes of stratum spinosum

melanoma

most deadly type of skin cancer due to aggressive growth and metastasis

skeletal system

Bones, cartilage, ligaments, other connective tissues

bones

primary organs of the system, form framework of the body, perform multiple functions

compact bone

dense or cortical bone, relatively dense connective bone tissue, 80% of bone mass

spongy bone

cancellous or trabecular bone, located internal to compact bone, appears porous, 20% of bone mass

cartilage

semi-rigid connective tissue, more flexible than bone

hyaline cartilage

supportive, connective, most common, lines joints

fibrocartilage

supportive connective, intervertebral disc, pubic symphysis, meniscus of kneww

elastic cartilage

supportive, connective, external ear, epiglottis

ligaments

anchor bone to bone

tendons

anchor muscle to bone

functions of bone

support and protection, leverage for muscles to move the bones, hemopoiesis, storage of mineral and energy reserves

bones function

as a system of levers for a muscles to contract and move the bones

hemopoiesis

the process of blood cell production

calcium

most abundant mineral in our body, stored in bones

phosphate

is also stored in bones

calcium is needed for

muscle contraction, blood clotting, nerve impulse transmission

phosphate is required for

ATP utilization, plasma membrane

lipids

stored in yellow bone marrow, in shafts of some adult bones

four classes of bone determined by shape

long bones, short bones, flat bones, irregular bones

short bones

length nearly equal to their width