anatomy and physiology chapter 4- skin and body membranes

functions of body membranes

covers body surfaces, lines body cavities, forms protective sheets around organs

how are body membranes classified?

according to tissue types

epithelial body membranes

cutaneous, mucous, serous

connective tissue body membranes

synovial

cutaneous membrane

skin, dry membrane, outermost protective boundary

2 regions of the cutaneous membrane

superficial epidermis and underlying dermis

what is the superficial epidermis composed of?

keratinized stratified squamous epithelium

what is the underlying dermis composed of?

mostly dense (fibrous) connective tissue

mucous membrane

lines all body cavities that open to the exterior body surface

why are moist membranes adapted?

absorption or secretion

where is stratified squamous epithelium located?

mouth and esophagus

where is simple columnar epithelium located?

the rest of the digestive tract

mucous membranes are held in place by…

underlying loose connective tissue (lamina propria)

lamina propria

loose connective tissue

serous membranes (serosa)

lines open body cavities that are closed to the exterior of the body

serous membranes (serosa) locations

heart, lungs, and abdominal cavity

surface of serous membrane

a layer of simple squamous epithelium

underlying layer of serous membrane

a thin layer of areolar connective tissue

serous membranes are double layered membranes separated by…

serous fluids

visceral layer of serous membrane

covers the outside of the organ

parietal layer of serous membrane

lines a portion of the wall of the ventral body cavity

how are serous membranes named?

first by later, then by location

peritoneum

abdominal cavity

pleura

around the lungs

pericardium

around the heart

synovial membrane

lines fibrous capsules (bursae, tendon sheaths)

the synovial membrane secretes…

synovial fluid (a lubricating fluid)

the integumentary system is made up of…

skin (cutaneous membrane) and skin derivatives (appendages)

examples of skin derivatives (appendages)

sweat glands, oil glands, hair, nails

skin functions

protects deeper tissues from mechanical, chemical, bacterial, UV, and thermal damage and dessication

dessication

drying out of the skin

keratin

a protein that protects the skin from water loss

what does the skin aid in?

loss of retention of body heat, excretion of urea and uric acid

what does the skin synthesize?

vitamin D

the skin houses…

cutaneous sensory receptors that detect touch, temperature, pressure, and pain

3 regions of the skin

epidermis, dermis, hypodermis

epidermis

outer layer of the skin, avascular, water tight barrier, 5 layers

dermis

deep layer, dense connective tissue, 2 layers

hypodermis (subcutaneous tissue)

not considered part of the skin, anchors skin to underlying organs, serves as shock absorber and insulates deeper organs

the hypodermis is composed of…

mostly adipose tissue

all layers of the epidermis are classified as…

stratified squamous epithelium

5 epidermal layers (deepest to most superficial)

stratum basale, stratum spinosum, stratum granulosum, stratum lucidium, stratum corneum

stratum basale layer is also known as…

stratum germinativum

stratum basale

deepest layer of epidermis, lies next to the dermis, cells are actively mitotic

how is the epidermis connected to the dermis?

wavy borderline of the stratum basale

what happens to the daughter cells of the stratum basale layer?

pushed upward to from more superficial layers

stratum lucidium is formed from…

dead cells of deeper strata

stratum lucidium occurs…

only in thick, hairless skin of the palms and soles of feet

stratum corneum

outermost layer of the epidermis, compact dead cells

keratinocytes

compact dead cells of the stratum corneum, filled with keratin, forms a watertight barrier

melanocytes are mainly in…

stratum basale layer

where do melanocytes accumulate?

in membrane-bound granules called melanosomes

the amount of melanin produces by melanocytes depends on…

genetics and exposure to sunight

epidermal dendritic cells are also called…

Langerhans cells

epidermal dendritic cells (Langerhans cells)

alert and activate immune cells to a bacterial or viral invasion

merkel cells

associated with sensory nerve endings, serve as touch receptors

3 pigments that contribute to skin colo

melanin, carotene, hemoglobin

what determines the extent of red coloring in hemoglobin?

oxygen content

hemoglobin

red coloring from blood cells in dermal capillaries

redness (erythema)

due to embarrassment, inflammation, hypertension, fever, or allergy

pallor (blanching)

due to emotional stress, anemia, low blood pressure, or impaired blood flow to an area

jaundice (yellowing)

liver disorder

bruises (hematomas)

black and blue marks

overall dermis structure

collagen and elastic fibers are located throughout the dermis, location of appendages of skin

what do collagen fibers do for the skin?

give the skin its toughness

what do elastic fibers do for the skin?

give the skin elasticity

the dermis is the site of…

blood vessels and nerve supply

2 layers of the dermis

papillary layer (upper dermal) and reticular layer (deepest skin layer)

dermal paillae

projections of the papillary layer

papillary layer of dermis

houses pain receptors, unique pattern makes up fingerprints

reticular layer of dermis

location of blood vessels, sweat and oil glands, and deep pressure receptors (lamellar corpuscles)

lamellar corpuscles

deep pressure receptors

all appendages of the skin are derived from…

epidermal layer

cutaneous glands are all…

exocrine glands (contain ducts and empty through pores)

two cutaneous glands

sebaceous (oil) glands and sudoriferous (eccrine sweat) glands

when are sebaceous glands activated?

puberty

where do sebaceous glands empty?

usually into hair follicles, some open directly onto skin

sebaceous (oil) glands

produces sebum (oil), lubricant for skin, prevents brittle haor, kills bacteria

sudoriferous (eccrine sweat) glands

produce sweat, widely distributed in skin

sudoriferous (eccrine sweat) glands functions

helps dissipate excess heat, excretes waste products

the acidic nature of sudiferous (eccrine sweat) glands inhibits…

bacteria growth

2 types of sudiferous glands

eccrine and apocrine

eccrine glands

open via duct through the pores, produce sweat

apocrine glands

ducts empty into hair follicles, releases sweat

when do apocrine glands begin to function?

at puberty

sweat is composed of…

mostly water, salts, vitamin c, some metabolic waste, fatty acids and proteins (apocrine only)

where does the odor of sweat come from?

associated bacteria

function of hair

to protect and conserve heat

hair follicle

dermal and epidermal sheath surround hair root

arrector pili muscle

smooth muscle, pulls hair upright when a person is cold or scared

associated structures of hair

hair follicle, arrector pili muscle, sebaceous and sudiferous glands

hair is produced by…

hair follicle

hair root is enclosed in…

the hair follicle

hair consists of…

hard keratinized epithelial cells

what provides pigment for hair color?

melanocytes

where does hair grow?

in the matrix of the hair bulb in stratum basale

hair anatomy

central medulla, cortex surrounding medulla, cuticle on the outside of the cortex

what is the most heavily keratinized region of the hair?

cuticle outside the cortex

what is responsible for nail growth?

the stratum basale that extends beneath the nail bed

nail

scale-like modification of the epidermis