Chapter 4 Flashcards
artifacts
minor distortions that alter a preserved tissue’s condition. this is why most microscopic structures are not exactly like living tissue
epithelial tissue or epithelium
sheet of cells that covers a body surface or lines a body. 2 forms: covering and lining (lines outer layer of skin, digestive system, respiratory system and organs in ventral body cavity) and glandular (fashions the glands in the body)
functions include: protection, absorption, filtration, excreatoin, secretion and sensory reception
polarity
characteristic of epithelium. all epithelia have an apical surface (upper surface exposed to exterior) and a lower attached basal surface. these two differ and exhibit a polarity. also includes microvilli and basal lamina
microvilli
part of epithelium. fingerlike extensions of membrane that increase exposed surface area. intestinal is brush border
basal lamina
adjacent to basal surface and acts as a selective filter that determines which molecules diffusing can enter the epithelium. connects epethelium to underlying connective tissue
specialized contacts
characteristic of epithelium. epithelial cells fit closely together. tight junctions and desmosomes bind adjacent cells together to help keep things from diffusing in
supported by connective tissue
characteristic of epithelium. the basal lamina and reticular lamina form the basement membrane which reinforces the epithelium sheet and prevents stretching and tearing
avascular but innervated
characteristic of epithelium. epithelium contains to blood vessels (avascular) and is supplied by nerve fibers (innervated).
regeneration
characteristic of epithelium. epithelial cells can reproduce themselves rapidly when some are destroyed. they replace lost cells by cell division
simple squamous epithelia
single layer of flattened cells. diffusion and filtration, protection is not important here. located in kidney, air sac of lungs, heart lining, blood vessels, serosae and lymphatic vessels
simple cuboidal epithelia
single layer of cube cells. secretion and absorption. located in kidney tubules, ducts of smallglands and ovary surface
simple columnar epithelia
single layer of tall cells. secretion and absorption of mucus and enzymes. located in digestive tract, gallbladder and excretory ducts of uterus
stratified squamous epithelia (non keratinized)
protects underlying tissues from abrasion. thick membrane of several cell layers. basal cells are cuboidal/columnar and they do mitosis to replace surface cells. located in the moist linings of esophagus, mouth ad vagina
stratified squamous epithelia (keratinized)
protects underlying tissues from abrasion. thick membrane of several cell layers. basal cells are cuboidal/columnar and they do mitosis to replace surface cells. located in the skin
endothelium
type of simple squamous epithelium. provides slick, friction-reducing lining in lymphatic vessels and in cardiovascular system organs (blood vessels and heart)
mesothelium
type of simple squamous epithelium. in serous membranes, lines the ventral body cavity and covers its organs
pseudostratified columnar epithelium
single layer of cells with differing heights. all start at basemen membrane. located in sperm carrying ducts, ducts of large glands, trachea and upper respratory tract
transitional epithelium
type of stratified epithelia. stetch to store urine. basal cells are cuboidal or columnar, surface cells depends on stretching. located in the uterus or bladder.
gland
one or more cells that make and secrete a product, called a secretion. classified by where they release their product (encorine or exocrine) and their cell number (unicellular, multicellular)
secretion
- product of gland, an aqueous fluid that usually contains fluids
- the process glands go through to make and release this product. glands obtain substances from the blood and transform them chemically into this product
endocrine glands
secrete internally. ductless glands. structurally diverse. they produce hormones (messenger chemicals) that they secrete by exocytosis into extracellular space. hormones travel by blood to target organs and prompt these organs to respond. e.g. pituatary gland, testes, ovaries, thyroid
exocrine glands
secrete externally onto the body surface (skin) or body cavities. they are diverse. unicellular produce mucus and do not have ducts. multicellular produce sweat, oil and have ducts
connective tissue
connects all parts of body together. most abundant and widely distributed primary tissue. 3 main components: ground substance, fibers, and cells. 4 main classes: connective tissue proper (fat and fibrous tissue of ligaments), cartilage, bone and blood.
functions are: 1. binding and supporting, 2. protecting, 3. insulating, 4. storing resserve fuel and 5. transporting substances
ground substance
structural element of connective tissue. acts as a medium for nutrients to diffuse between blood capillaries and the cells. made of fluid, adhesion proteins and proteolycans. fills space between cells
connective tissue fibers
a structural element of connective tissues. these provide support. 3 types of fibers: collagen fibers, elastic fibers and reticular fibers
collagen fibers
type of connective tissue fibers. the strongest and most abundant. stronger than steel. constructed of the fibrous protein collagen
elastic fibers
type of connective tissue fibers. long, thin fibers that form branching networks in the extracellular matrix. made of protein elastin, which stretches and recoils like rubber bands. these are located where elasticity is needed (skin, lungs and blood vessel walls and aorta).
reticular ribers
type of connective tissue fibers. short branching fibers, collagenous fibers that branch extensively and form delicate fibers that surround small BV and support soft tissue of organs (in spleen). abundant where connective tissue is in contact with other tissue types
connective tissue cells
structural element of connective tissues. in extracellular matrix. help in binding, support, insulation, and protection. these exist in immature and mature forms. immature cells have the “-blast” suffix and are active cells that secrete the ground substance. mature cells have the “-cyte” suffix which are less active and maintain the health of the matrix.
other types include fat cells, white blood cells, mast cells and macrophages
mast cells
a type of connective tissue cell. they cluster around blood vessels and detect foreign microorganisms and initiate local inflammatory responses against them and secrete chemicals that mediate inflammation. release histamine
mesenchyme
a common embyonic tissue that gives rise to mature connective tissues. it arises during early weeks of embryonic development and differentiates into all types of connective tissue cells. some of these cells remain and provide a source of new cells in mature connective tissues.
connective tissue proper-loose connective tissues subclass
type of conntective tissue. these have 3 subdivisoins: areolar, adipose and reticular
areolar connective tissue
type of connective tissue proper (loose connective tissue). it is a gel-like matrix with fibroblasts, macrophages, mast cells and WBC and loose arrangement of fibers. it supports and binds tissues, wraps and cushions organs. hold tissue fluids and helps defend against infections and inflammation.
widely distributed under epithelia in body. forms lamina propia of mucous membranes. package organs and surround capillaries
adipose tissue
type of connective tissue proper (loose connective tissue). it is a sparse matrix made of closely packed fat cells (adipocytes). it provides a reserve food fuel, insulation, supports/protects organs. located under the skin in subcutaneous tissue, around kidneys and eyeballs, and in abdomen and breasts.
reticular tissue
type of connective tissue proper (loose connective tissue). limited to certain sites, found in loose ground network. forms soft internal skeleton (stroma) and supports other cells (WBC,mast and macrophages). located in lymphoid organs (lymph nodes, bone marrow and spleen).
connective tissue proper (dense connective tissue)
type of connective tissue proper. this has 3 sub divisions: dense regular connective tissue (often called fibrous connective tissue) and dense irregular connecive tissue and elastic connective tissue
dense regular connective tissue
type of connective tissue proper (dense connective tissue). closely packed parallel collagen fibers that withstand great resistance to being pulled. these are in tendons (attach muscles to bones) and ligaments (bind bones together at joints).most common cell is fibroblast.