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128 terms

human anatomy exam 2

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tissues
group of cells similar in structure and function
four basic tissue types
epithelial, connective, muscle, and nervous
epithelial tissue
is a sheet of cells that covers the body surface or lines a body cavity
two types of epithelia
covering and lining and glandular epithelia
covering and lining epithelia
forms the outer layer of the skin
lining in the body cavities
covers the surface of visceral organs
glandular
cover the glands of the body
functions of epithelium
protection, absorption, filtration, excretion, secretion, sensory reception
characteristics of epithelial tissues
-composed of tightly packed cells that form a sheet
-cells are connected by tight juntions and desmosomes
-free surface (apical) is exposed to the lumen (opening) of internal organs
basal surface of basement membrane
support of cells
forms boundaries between tissue layers
lie on top of connective tissue
avascular
tissue does not contain blood vessels
inerverted
tissue is supplies with nerve tissues
cell regeneration
through mitosis
simple squamous
single layer, flattened cells, disc shaped central nucliei, sparse cytoplasm.
allows filtration or secretion
air sacs of lungs.
simple cuboidial
single layer of cubelike cells with large spherical central nucliei,
used for secretion and absorption
found in kidney tubules
simple columnar
single layer of tall cells round to oval nucliei
absorption anad secretion of mucous, enzymes and other substances
location: nonciliated type lines most of the digestive tract (stomach to anal canal), gallblader
pseodstratified columnar
single layer of cells differeing hieghts
used in secretion
found in ciliated variety lines the trachea, most of the upper respiratory system
stratified squamous
thick membrane composed of several cell layers, basal cells are cuboidial or columnar and metabollically active , surface cells are flatten
function: protects underlying tissues in areas subjected to abrasion
location: nonkeratinized stype forms the moist linings of the esophagus, mouth and vagina
transitional epithelial
resembles both stratified squamous and stratified cuboidial. surface cells dome shaped or sqamous.
function: stretches readily and permits distention of urinary organ by contained urine.
location: lines the uretus, urinary bladder, and part of the urethra.
gland
is composed of one or more cells that is/are specialized to produce and secrete substance into ducts or body fluids
endocrine glands
ductless and secrete hormones that travel through lymph or blood to target organs
exocrine glands
numerous, many of their products are familar, secrete their product on their body surfaces, or into body cavities.
ex. mucous, sweat, oil, salivary galnds, the pancreas(which synthesizes digestive enzymes)
what three things carry out both exocrine and endocrine functions
pancreas, testes and ovaries
two structural types of exocrine glands
unicellular and multicelluar glands
goblet cells
epithethial cell
-does not have ducts, only ductless exocrine gland in body
- one cell
-secrete mucous to lubricate tissue
found in respiratory, digestive, urinary and reproductive tracts
three types of exocrine glands
merocrine, holocrine, apocrine
merocrine glands
most common,
glands release fluid products by exocytosis
secretion is only produced on demand
-pancreas, salivary and mucous glands
holocrine glands
-secretions accumulate within their cells until they rupture and die
-sebaceous glands
apocrine glands
modified sweat glands
-secretion accumulate at the tip of each cell
- the tips of cells pinch off to release secretion
-rare, remaing part of cell regenerates
-ex. mammary glands
functions connective tissue
- needed for binding structures
-support
-protection, insulation
-cushion
-fill spaces between tissue
-produce blood cells
characteristics of connective tissue
-derived from embryonic tissue called mesenchyme (stem cell)
-most are highly vascular (rich in blood supply) except cartilage (avascular- no blood supply) and tendons are slightly avascular
-CT cannot be found on free surfaces
-innervated except for cartilage
consist of 3 elements (cells, fibers, no shape(amorphous))
-contains matrix- ground substance+fibers, matrix excreted by cells. Consistency of matrix varies from a liquid to solid
blast cells
-immature cells of Connective tissue (CT)
-blast-spout or produce
-undergo rapid mitosis
-secrete the matrix of CT
types of blast cells
Fibroblast, chondroblast, osteoblast, hemocytoblast
fibroblast
immature cells
-large flat cell with branche processes
-most common type in CT
-secrete fibers into matrix
chondroblast
secrete the matrix of cartilage
osteoblast
secrete the matrix of bones
hemocytoblast
produce all blood cells
cyte cells
-mature cells of CT
maintain the health or condition of the matrix
macrophages
-originate as white blood cells
-carries out an immune response
-carry out phagocytosis, clean tissue of bacteria and foreign organisms
mast cells
large cells found near blood vessels
-release heparin and histamine
plasma cells
-small cells that secrete antibodies
collagen fibers
collagen- the most structural protein
-appears as thick and whitish threads
-fibers grouped in a long parallel bundle
flexible, slightly elastic
-great tensile strength( can resist pulling)
-found most abundant in ligaments and tendons
elastic fibers
protein called elastin
- weaker than collagenous fibers
-highly stretchable
-common in body parts that stretchsuchs as the vocal cords, air tubes, skin, and blood vessels
reticular fibers
very thin collagen fibers
form delicate supporting networks
-supports soft organs, fat cells nerve and muscle cells
dense irregular connective tissue
-pimarily irregularly arranged collagen fibers; some elastic fibers; major cell type is the fibroblast.
-able to withstand tension exerted in many directions, provides structural strength
-located in the dermis of the skin
dense regular CT
-primarily parallel collagen fibers, a few elestic fibers, major cell type is fibroblast
-function- attatched muscles to bones or to muscle; attached bones to bones, withstands great tensile stress when pulling force is applied in one direction
-location, tendons, most ligaments, apopneruroses
adipose tissue
-matrix as in areolar, but very sparse,closely packed adiposecytes or fat cells have nucleus pushed to the side by large fat droplet
-function, provides reserve food fuel, insulates against heat loss supports and protects organs.
-location-under skin in the hypodermis, around kidneys and eyeballs; within abdomen in breast
areolar tissue
-gel-like matrix with all three fiber types; cells, fibroblast, macrophages, mast cells and some white blood cells.
-function- wraps and cushions organs; its macrophages phagocytize bacteria; plays important role in inflamation; holds and conveys tissue
-location-widely distributed under epithelia of body e.g forms lamina propria of mucous membranes; packaging organs; surrounds cappilaries
cartilage
-tough, flexible but rigid
-can withstand tension and compression
-provides support, framework, attachments and protection
-matrix abundant with collagen and elastic fibers,
- predominant cells chondroblast and chondrocytes (encased within lacunae)
-avascular
-not innerverted
hyaline cartilage
-amorphous but firm matrix, chondroblast produce the matrix
-supports and reinforces; has resilient cushioning properties; resist compressive stress
- forms most of the embryonic skeleton; covers the end of long bones in joint cavities; forms costal cartilage of the ribs, cartilage of the nose trachea, and larynx
elastic cartilage
-similar to hyaline cartilage but more elastic fibers in matrix
-maintains the shape of a structure while alowing great flexibility
-supports external ear
fribrocartilage
-matrix is similar to but less firm than that in hyaline cartilage, thick collagen fibers predominate
-tensile strength with the ability to absorb compressive shock
-intervertebral disc; pubic symphysis; disc of knee joint
bone
most rigid CT
-matrix solid and hard due to mineral salts such as calcium phosphate and calcium carbonate
-function-protection and support, attachments for muscles, make blood cells, stores and releases inorganic salts, predominant cells called osteoblast, osteoclast and osteocytes ecased with lacunae
blood
-liquid CT
-matrix called plasma
-plasma contains - white blood cells- fight diseases via phagocytosis -red blood cells- transport respiratory gases
-platelets- needed for blood clotting
-fibers of blood called plasma proteins
-Function- transport nutrients, hormones waste, respiratory gases and other substances
nervous tissue
found in brain, spinal cord and peripheral nerves
-cells called nerons and neuroglia
nerons
-amoitotic
-transmit electrical impulses throughout body
neuroglia
-support cells
-highly mitotic
nervous system
regulate and control body functions
muscle tissue
-tissue specialized to contract or shorten
-muscle cellsare elongated referred to as muscle fibers
-well vascularized
-function-provide motion, maintain posture, generate heat
skeletal tissue
-long, cylindrical, multinucleate cells, obvious striations
-voluntary movement locomotion; locomotion manipulation of the environment; facial expression; voluntary control.
-in skeletal muscles, attached to bones or occasionally to skin.
cardiac muscle
-branching, striated, genaerally uninucleate cells that interdigitate at specialized junctions.
-as it contracts, it propels blood into the circulation; involuntary control
-the walls of the heart
smooth muscle
-spindle-shaped cells with central nucliei; no striations, cells arranged closely to form sheets
-propels substances or objects (foodstuffs, urine, a baby) along internal passageways; involuntary control.
-mostly in walls of hollow organs.
tissue repair
occurs in two major ways 1) regeneration 2) fibrosis
regeneration- the replacement of destroyed tissue with the same kind of tissue
fibrosis- involves the formation of scar tissue
four major membranes of the body
serous, mucous,synovial, cutaneous
serous membrane(wet)
-line body cavities that do not open to the body exterior
-form inner linings of the thorax and abdominal and covers the organs with the cavities
-composed of two layers- parital(line cavities) visceral(line surface of organs)
-cells secrete watery serous fluid, which lubricates surface
mucous membrane(wet)
-line cavities and tubes that open to the exterior of the body
-areas include- oral and nasal cavities, digestive tube, respiratory, urinary and reproductive ststems
-mucous membrane consist of epithilium which overlie a layer of loose connective tissue called the aminapropria (sub layer of mucous membrane, simple columnar, stratified squamous)
-membrane contain goblet cells
synovial membrane (wet)
-forms inner linings of joint cavities
-cells of membranes secrete a thick colorless synovial fluid into joint cavity
cutaneous membrane(dry)
skin-integumentary system
dry membrane
ectoderm
outer layer
mesoderm
middle layer
endoderm
inside layer
epidermis
superficial layer, outermost protective layer, composed of epithelial cells
dermis
-deep layer underneath the epidermis
-make up bulk of skin
-tough and leathery
-composed of epithelial cells
-well vascularized to supply epidermis
-well innervated
-regulate body temp
subcutaneous layer (hypodermis)
-not a skin layer
- found underneath the dermis layer of skin
-consist of adipose and areolar CT
-store fat
-anchors skin to underlying structures
-contain major blood vessels that supply the skin
-shock absorber
epidermis layer
-contain keratinized stratified squamous epithilium
-four cell types-kerotinocytes, melanocytes, langerhans cells, merkel cells
keritinocytes
chief or most abundant cells in epidermis
-produce kertin (tough, water proofing protein)
-flaten cells with scale like apperance
-surface keratinocytes are dead, slough off
melanocytes
spider shaped cells
-produce melanin, (pigment)
-found in deepest layer of epidermis
langerhans cells
star shaped
-arise from bone marrow then migrate to epidermis
-known as macrophages (mature cells)
merkel cells
spiky appearance
-found at the junction between epidermis and dermis skin layers
-associated with a nerve disc forming a merkel disc
skin has four strata layers (thick have 5)
stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum.
stratum basale
deepest layer
-cells active in mitosis
-one layer
-containt young keritinocytes, melanocytes and merkel cells
-attached to dermis
stratum spinosum
-several layers of thickness
-keritinocytes have developed spiny projections (called prickle cells)
-langerhans cells most abundant
stratum granulosum
consist of 3-5 cell layers in thickness
-keritinocytes accumulate granuls in cytoplasm
-kertin forms
stratum lucidum (thick layer only)
abesnt in thin skin
-lies above granulosum layer
-few layers of dead keritinocytes
stratum corneum
superficial thick layer
-sloughing noted in this layer
-20-30 cell layers
-keritinocytes are shingle like in appearance
two dermis layers
papillary layer, reticular layer
papillary layer
thin superficial layer
-make up 20% of the dermis
-contain peg-like projections celled dermal papillae which produce the ridges of fingertips
-dermal papillae contain- capillary loops- produce nutrients to the epidermis - meissners corpuscles- touch receptors
reticular layer
deep layer
-makes up 80% of dermis
contains pacinan corpuscles- pressure sensitive receptors
- contain sweat and sebaceous glands
melanin
- major skin pigment color range,
-pigment from yellow-red-black
-local accumulation of melanin produce freckles and moles
carotene
yellowish-orange pigment
-abundant in soles and palms
-pigment acculates in the stratum corneum and hypodermis
oxygenated hemoglobin
red pigments of red blood cells
-produce pinkish tint to skin
alterations of skin color-redness
due to blushing, fever, inflamation, hyper tension and allergy
alterations of skin color-blanching
pale skin due to anemia of emotional stress
alterations of skin color-jaundice
yellowish appearance due to disorder of the adrenal glands
alterations of skin color-bruising
black blue due to hematoma(clotted blood mass)
sweat glands
-two major types-eccrine and apocrine
-located in all skin areas except nipples of breast and part of human genetalia
-two modified sweat glands-ceruminous glands, mammary glands
eccrine (merocrine) glands
most numerous
-abundant in palms, soles, forehead, and scalp
-duct extends to surface of skin, opens into a pore
-secretion- called sweat (prevents the body from over heating known as thermoregulation)
-composition-99%water, salts, nitrogen, waste, vitamin C, lactic acid, antibodies, pH 4-6
-regulatede by sympathetic division of ans
-emotional sweating called cold sweat
apocrine glands
-found most abundant in armpits and genital region
-larger in size than eccrine glands
-ducts empty into hair follicle
-secretion contains lipids and protiens
-odoless unless mixed with bacteria
-become fully funtion at puberty
-secretions do not function in thermoregulation
ceruminous glands
found in external ear canal, secrete earwax or cerumen, functions as protection
mammary glands
found in the breast; specialized to secrete milk
sebaceous glands
-secrete sebum (oily secretion)
-sebum softens and lubricates the hair and skin
-holocrine glands by function (cells accumulate sebum, swell and burst)
-sebum released into hair folicles and onto skin surface
-glands scattered throughout skin except in the palms and soles
-androgens (male-like hormones) stimulate the secretion of sebum
-glands become very active during puberty inactive at childhood
-blocked sebaceous gland ducts produce whiteheads and blackheads on skin
-inflamed sebaceous glands cause acne or pimples
-overeactive sebaceous glands cause seborrhea (oily scales on scalp) known as "cradle cap" in infants
hair follicles
-hair present in all skin areas except palms, soles, lips, nipples, and part of the external genitalia
-needed for protection and filtration
-hair produced in hair follicle
- follicle extends from epidermis into the dermis layer of skin
structure of hair follicle
-structure- hair bulb, root hair plexus, hair papilla, connective tiisue root sheath, epithelial root sheath, arrector pili
hair bulb
expanded base of hair follicle
root hair plexus
wrapped around bulb
hair papilla
nipple like; provides nutrients for hair growth
connective tissue root sheath
derived from the dermis; makeup outer wall of the hair follicle
epithelial root sheath
derived from an invagination of the epidermis
arrrector pili
associated with each hair follicle, is a bundle of smooth muscle cells
structure of hair
-shaft
-root
shaft
major region of hair; extends above skin
root
embeded in dermis
shapes of shafts
-flat and ribbon
-oval
-round
layers of shaft
-medulla
-cortex
-cuticle
medulla
central core; absent in fine hair
cortex
middle bulky layers around medula
cuticle
outermost layer, composed of overlapping cells
hair types
vellus- fine
terminal hair-coarse, found on scalp, eyebrows, pubic region, axillary, face and chest
hair growth
avg, 2mm/week
alopecia-thining or baldness condition of scalp, male pattern baldness most common
nails
-protective coverings of fingers and toes
-contains protein keratin
-nail structure -free edge, body root
-nail matrix- proximal portion producing nail growth
-lamule- whitish area on nail at proximal end
skin cancer
a tumor that does not spread is benign
-a tumor that spreads (metastisize) is malignant or cancerous
-most common type of skin cancer is exposure to ultraviolet light
-three types of cancer-basal, squamous, melanoma
basal cell carcinoma
least malignant and most common skin cancer
-lesions occur on the face
-80% of skin cancer
-highly curable
-proliferate, invading the dermis and epidermis
squamous cell carcinoma
-second most common skinn cancer
-arise from the keratinocytes of the stratum spinosum
-lesion arise on head, ears, scalp, lower lip and hands
curable if it does not spread
melanoma
cancer of the melanocytes and most dangerous
- highly metastatic and resistant to chemotherapy
-originates from preexisting moles that get larger
burns
causes tissue damage resluting from excessive heat or exposure to chemicals
first degree burn
-superficial partial thickness burn
-pain, redness, flaring of skin
-ex mild sunburn
-healing 7-10 days
second degree burn
-deep partial thickness burn
-damages the epidermis and upper layer of dermis
-some skin appendages are lost
-this wound occurs from open flames, hot objects and chemicals
-ex. formation of a blister
-healing 2-3 weeks
third degree burn
-full thickness burn
-damages the epidermis and dermis layer and accessory organs in the skin
- all skin functions are lost
-life threatening conditions
-skin becomes tough leathery and numb, skin graphing required, leaving extensive scars
rule of nines
a method to estimate the extent and severity of burns
-it divides the body into 11 areas, each accounting for 9% of the total body area plus 1% for the genitals