Section 1
Preview this deck
endothelium
Front
| 5 | 0 | ||
| 4 | 0 | ||
| 3 | 0 | ||
| 2 | 0 | ||
| 1 | 0 |
Active users
0
All-time users
0
Favorites
0
Last updated
4 years ago
Date created
Mar 1, 2020
Cards (117)
Section 1
(50 cards)
endothelium
slick lining of hollow organs
stratified epithelia properties
contain two or more layers of cells, regenerate from below (basal layer), major role is protection, named according to shape of cells at apical layer
endocrine glands
endocrine glands lack ducts, so they are often referred to as ductless glands. they secrete directly into the tissue fluid that surrounds them. endorine glands produce messenger molecules called hormones, which they release into the extracellular space. These hormones then enter nearby capillaries and travel through the bloodstream to specific target organs. each hormone signals its target organs to respond in some characteristic way.
stratified columnar epithelium
several cell layers, basal cells usually cuboidal; superficial cells elongated and columnar. function is for protection and secretion, location is rare in the body, small amounts in male urethra and in large ducts of some glands.
specialized contacts
adjacent epithelial cells are directly joined at many points by special cell junctions
tight junction
in the apical region of most epithelial tissues, a beltlike junction extends around the periphery of each cell. this is a tight junction. at tight junctions, adjacent cells are so close that some proteins in their plasma membranes are fused. this fusion forms a seal that closes off the extracellular space thus a tight junction prevents molecules from passing between the cells of epithelial tissue. an example would be tight junctions in the digestive tract keeping digestive enzymes, ions, and microorganisms in the intestine from seeping into the blood stream.
epithelial surface features
epithelial cells are composed of many cells closely joined together by special cell junctions along their lateral walls. Epithelial tissues also have distinct apical and basal regions. The apical region of certain epithelia has modifications associated with specific functions.
Cilia
whiplike bristles on the apex of epithelial cells that beat rhythmically to move substances across certain body surfaces.
specialized types of simple squamous epithelium
endothelium, mesothelium
desmosomes
the main junction for binding cells together are called desmosomes, also known as anchoring junctions. these adhesive spots are scattered along the abutting sides of adjacent cells. Desmosomes have a complex structure: on the cytoplasmic face of each plasma membrane is a circular plaque. The plaques of neighboring cells are joined by linker proteins, which project from both cell membranes and interdigitate like the teeth of a zipper in the extra cellular space. In addition, intermediate filaments insert into each plaque from its inner cytoplasmic side, bundles of these filaments extend across the cytoplasm and anchor at other desmosomes on the opposite side of the same cell. Overall, this arrangement not only holds adjacent cells together but also interconnects intermediate filaments of the entire epithelium into one continuous network of strong wires. These junctions are common in tissues that experience great mechanical stress. Plaques of adjoining cells are joined by proteins called cadherins, regular cell shape and structure by cell-cell interactions, class of calcium dependent adhesion molecules.
stratified epithelium
it has more than one layer.
mesothelium
visceral serosa, it lines the peritoneal, pleural, pericardial cavities, covers visceral organs of those cavities.
adhesion proteins
link plasma membranes of adjacent cells
Special characteristics of epithelial tissue
cellularity, specialized contacts, polarity, support by connective tissue, avascular but innervated, regeneration
Functions of Epithelium
Protection, absorption, secretion and ion transport, filtration, and forms slippery surfaces.
polarity
all epitehlia have a free upper surface (called apical) and a lower surface (called basal). they exhibit polarity, a term meaning that the cell regions near the apical surface differ from those near the basal surface.
Simple epithelium
the epithelium is only one cell layer
regeneration
epithelial tissue has a high regenerative capacity. as long as epithelial cells receive adequate nutrition, they can replace lost cells quickly by cell division.
Four types of tissue
epithelium, connective, muscle, nervous
stratified squamous epithelium description
thick membrane composed of several cell layers; basal cells are cuoidal or columnar and metabolically active, surface cells are flattened and squamous. in the keratinized type, the surface cells are full of keratin and dead; basal cells are active in mitosis and produce the cells of the more superficial layers
support by connective tissue
all epithelial sheets in the body are supported by an underlying layer of connective tissue
transitional epithelium
resembles both stratified squamous and stratified cuboidal, basal cells cuboidal or columnar; surface cells dome shaped or squamous like, depending on the degree of organ stretch, function is to stretch readily and permit distension of urinary organ by contained urine, located lining the ureters, bladder, and part of the urethra.
Epithelium
a sheet of cells that covers a body surface or lines a body cavity, with minor exceptions, all of the outer and inner surfaces of the body are covered by epithelia. Examples include the outer layer of the skin; inner lining of all hollow viscera, such as the stomach and respiratory tubes; the lining of the peritoneal cavity; the lining of all blood vessels
Tissue
A group of cells of similar structure that perform a common function
stratified cuboidal epithelium
generally two layers of cubelike cells, function is for protection, located in the largest ducts of sweat glands, mammary glands, and salivary glands.
Squamous cells
flat cells
stratified squamous epithelium function and location
protects underlying tissues in areas subjected to abrasion, keratinized variety forms the epidermis of the skin, a dry membrane, nonkeratinized type forms the moist linings of the esophagus, mouth and vagina.
Cellularity
epithelia are composed almost entirely of cells, these cells are separated by a minimal amount of extra cellular material, mainly projections of their integral membrane proteins into the narrow spaces between the cells.
adhesive belt junctions
just below the tight junctions in epithelial tissue are adhesive belt junctions, a type of anchoring junction. Transmembrane linker proteins attach to the actin microfilaments of the cytoskeleton and bind adjacent cells. this junction reinforces the tight junctions, particularly when the tissues are stretched. together with tight junctions, these form the tight junctional complex around the apical lateral borders of epithelial tissue.
unicellular exocrine glands
goblet cell is a one celled exocrine gland that is shaped like a goblet, these are scattered within the epithelial lining of the intestines and respiratory tubes, between columnar cells with other functions. They produce mucin, that dissolves in water when secreted, the resulting complex of mucin and water is viscous, slimy mucus. Mucus covers, protects, and lubricates many internal body surfaces.
Epithelium purpose
Its main role is to be a boundary layer and interface tissue, separating the inside of the body from the outside. In this way, new stimuli can be experienced at the boundary layer, so epithelia both protect the underlying tissues and contain nerve endings for sensory reception. Epithelia function in diffusion, secretion, absorption, and ion transport.
cell junctions
the most important of lateral surface factors, they are characteristic of epithelial tissue but are found in other tissue types as well. there are several types, tight junctions, adhesive belt junctions, desmosomes, gap junctions
ducts
carry products of exocrine glands to the epithelial surface.
cuboidal cells
shaped like cubes
glands
epithelial cells that make a secrete a product form glands, the products of glands are aqueous (water based) fluids that usually contain proteins. glands are classified as endocrine or exocrine depending on where they release their product, and as unicellular or multicellular based on the cell number.
Epithelium cell shapes
Squamous, cuboidal, columnar
microvilli
are microscopic cellular membrane protrusions that increase the surface area of cells, and are involved in a wide variety of functions, including absorption, secretion, cellular adhesion,
keratin
keratin refers to a family of structural proteins, it is the key of structural material making up the outer layer of skin.
simple columnar epithelium
secretion and absorption, ciliated types propel mucus or reproductive cells. lines the digestive tube from the stomach to the anal canal. It functions in the active movement of molecules, namely in absorption, secretion, and ion transport. It is thin enough to allow large numbers of molecules to pass through quickly, yet thick enough to house the cellular machinery needed to perform the complex processes of molecular transport.
columnar cells
taller than they are wide
multicellular exocrine glands
each has two basic parts, an epithelium walled duct and a secretory unit consisting of the secretory epithelium. Also, in all but the simplest glands, a supportive connective tissue surrounds the secretory unit, carrying with it blood vessels and nerve fibers. simple glands have an unbranched duct, whereas compound glands have a branched duct. they are tubular if their secretory cells form tubes and alveolar if the secretory cells form spherical sacs.
simple cuboidal epithelium
this epithelium forms the secretory cells of many glands, the walls of the smallest ducts of glands, and of many tubules in the kidney, its functions are the same as the simple columnar epithelium.
basal lamina
noncellular supporting sheet between the epithelial tissue and the connective tissue deep to it. consists of proteins secreted by epithelial tissue cells. Functions: it acts as a selective filter, determining which molecules from capillaries enter the epithelium, and acts as scaffolding along which regenerating epithelial cells can migrate, the basal lamina and reticular layers of the underlying connective tissue deep to it form the basement membrane.
stratified epithelia description
many layers of cells, squamous in shape, deeper cell layers appear cuboidal or columnar, thickest epithelial tissue, adapted for protection from abrasion.
exocrine glands
numerous, they produce familiar products. all exocrine glands secrete their products onto body surfaces or into body cavities, and multicelluar exocrine glands have ducts that carry their product to the epithelial surfaces. their activities are local, that is the secretion acts near the area where it is released. they include many types of mucus secreting glands, the sweat and oil glands of the skin, salivary glands of the mouth, the liver, pancreas, mammary glands, and many others.
lateral surface features
three factors act to bind epithelial cells to one another, one is adhesion proteins in the plasma membranes of the adjacent cells link together in the narrow extracellular space, two the wave contours of the membranes of adjacent cells join in a toungue and groove fashion, and three there are special cell junctions.
epithelial surface features
apical surface features include microvilli which are finger like extensions of plasma membrane, they are abundant in ET of small intestine and kidney, maximize surface area across which small molecules enter or leave, act as stiff knobs that resist abrasion. Cilia is a whip like, highly motile extension of apical surface membranes, cilia moves in coordinated waves to for example sweep dust out of lungs ect.
avascular but innervated
epithelium is avascular, meaning it lacks blood vessels, instead epithelial cells receive their nutrients from capillaries in the underlying connective tissue. Epithelial cells are penetrated however by nerve endings, that is why it is innervated.
simple squamous epithelia
diffusion and filtration, secretion in serous membranes. Thin and often permeable, this membrane occurs wherever small molecules pass through a membrane quickly, by processes of diffusion and filtration
Gap junction
tunnel like junction that can occur anywhere along the lateral membranes of adjacent cells. Gap junctions function in intercellular communication by allowing small molecules to move direction between neighboring cells. At such junctions, the adjacent plasma membranes are very close and the cells are connected by hollow cylinders of protein. Ions, simple sugars, and other small molecules pass through these cylinders from one cell to the next. Gap junctions are common in embryonic tissues and in many adult tissues, including connective tissues. function in intercellular communication
Section 2
(50 cards)
dense irregular connective tissue
similar to areolar tissue, but its collagen fibers are much thicker, these fibers run in different planes, allowing this tissue to resist strong tensions from different directions. this tissue dominates the leathery dermis of the skin.
collagen
strongest and most abundant type of fiber in connective tissue, collagen fibers resist tension and contribute strength to a connective tissue.
osteoblasts
cells that secrete matrix in bone.
three types of cartilage
hyaline, elastic, fibrocartilage
skeletal muscle
pull on bones to cause body movements, long large cylinders that contain many nuclei
special characteristics of connective tissue
relatively few cells lots of extracellular matrix, extracellular matrix composed of ground substance and fibers, all connective tissues originate from embryonic tissue called mesenchyme.
macrophages
phagocytic cells which engulf foreign bodies.
chondroblasts
cells that secrete the matrix in cartilage tissue
areolar connective tissue
most widespread connective tissue proper, underlies almost all the epithelia of the body and surrounds almost all the small nerves and blood vessels, including the capillaries, it is used to support body tissues, hold body fluids, defend body against infection, and store nutrients as fat, first line of defense against invading microorganisms.
hyaline cartilage
supports and reinforces; has resilient cushioning properties; resists compressive stress, forms most of the embryo skeleton, covers the ends of long bones in joint cavities, cartilage of the nose, trachea and larynx, forms costal cartilages of the ribs
smooth muscle tissue
no visible striations in its cells, have tapered ends and one centrally located nucleus, occur in hollow viscera such as digestive and urinary organs, uterus and blood vessels.
elastic cartilage
supports external ear, similar to hyaline but more elastic fibers in the matrix
serous membrane
slippery membrane, line closed cavities, pleural, peritoneal, and pericardial cavities, simple squamous epithelium lying on areolar connective tissue.
interstitial fluid
watery fluid that occupies the extracellular matrix, tissue fluid derives from blood
3 types of muscle tissue
skeletal, cardiac, smooth
four main classes of connective tissue
connective tissue proper, cartilage, bone tissue, blood
inflammation signs
increased blood flow produces heat, increased blood flow causes skin redness, swelling due to increase of interstitial fluid at site, pain due to pressure on pain receptors from increased fluid
ground substance
viscous, spongy part of extracellular matrix, consists of sugar and protein molecules, made and secreted by fibroblasts
reticular fibers
bundles of a special type of collagen fibril. these short fibers cluster into a meshlike network that covers and supports the structures bordering the connective tissue.
inflammatory response to injury
nonspecific, local response, limits damage to injury site
osteocytes
mature bone cells in lacunae
cutaneous membrane
skin
three types of protein fibers in extracellular matrix
collagen, reticular, elastic. each has unique properties but all function in support.
loose connective tissue subclasses
areolar, adipose, and reticular
elastic fibers
contain rubber band like protein elastin, which allows them to function like rubber bands, stretching and then returning to previous form when tension is released.
classification of connective tissue
loose connective tissue, dense connective tissue
connective tissue
the most diverse and abundant tissue
covering and lining membranes
3 types, cutaneous membrane, mucous membrane, serous membrane
cartilage
firm, flexible tissue, contains no blood vessels or nerves, matrix contains up to 80% water, only one cell type, chondrocyte. each chondrocyte resides in a cavity in the matrix called the lacuna.
elastic connective tissue
elastic fibers are the predominant type of fiber, this tissue is located in structures where recoil from stretching is important, within walls of arteries, in certain ligaments, and surrounding the bronchial tubes in the lungs.
cardiac muscle
contracts to propel blood through blood vessels, differ in two ways, each cardiac cell has just one nucleus, cardiac cells branch and join at special cellular junctions called intercalated discs
plasma cells
mark cells for death, present antibodies
mast cells
release granules (histamine) to increase bloodflow
major functions of connective tissue
support and binding other tissues, holding body fluids, defending body against infection, storing nutrients as fat
bone tissue description
calcified matrix containing many collagen fibers, well vascularized
blood cells
the cellular components of blood function is to carry respiratory gas (red blood cells) to fight infections (white blood cells) and to aid in blood clotting (platelets).
reticular connective tissue
resembles areolar tissue but the only fibers in its matrix are reticular fibers, the bone marrow, spleen, and lymph nodes, which house many free blood cells outside their capillaries, consist largely of reticular connective tissue.
mucous membrane
lines hollow organs that open to surface of body, epithelial sheet underlain with a layer of lamina propria
fibroblasts
cells in connective tissue proper that make the protein subunits of fibers, which then assemble into fibers when the cell secretes them. fibroblasts also secrete the molecules that forms the ground substance of the matrix.
additional cell types in connective tissue
fat cells store energy, neutrophils, lymphocytes and macrophages all are white blood cells that respond to and protect against infectious agents, mast cells release signaling molecules that mediate the inflammating reaction and promote healing
blood
red and white blood cells in a fluid matrix composed of plasma, transport of respiratory gases, nutrients, wastes, and other substances, develops from mesenchyme and consists of blood cells surrounded by nonliving matrix, the liquid blood plasma
muscle tissue
brings about body movements, have an elongated shape and contract forcefully as they shorten. these cells contain many myofilaments, cellular organelles filled with actin and myosin filaments that bring about contraction in all cell types
adipose tissue
similar to areolar in structure and function, but its nutrient storing function is much greater. adipose tissue is crowded with fat cells, which make up 90% of its mass. it removes lipids from the blood stream after meals and later releases them in the blood as needed.
dense regular connective tissue
all collagen fibers usually run the same direction, parallel to the direction of the pull. crowded between the collagen are rows of fibroblasts, which continually manufacture the fibers and ground substance. this tissue is poorly vascularized and contains no fat or defense cells.
immune response
takes longer to develop and very specific, destroys particular microorganisms at site of infection
function of bone tissue
supports and protects organs, provides levers and attachment site for muscles, stores calcium and other minerals, stores fat, marrow is site for blood cell formation.
fibrocartilage
less firm than hyaline; thick collagen fibers predominate, intervertebral discs, pubic symhysis, discs of knee joint
fascia
a fibrous membrane that wraps around muscles, muscle groups, large vessels, nerves
connective tissue proper dense connective tissue
contains more collagen than areolar connective tissue does. with its thick collagen fibers it can resist extremely strong tensile forces, there are three types of dense connective tissue, irregular, regular, and elastic.
osteoblasts
secrete collagen fibers and matrix
Section 3
(17 cards)