powerpoint #2 tissues Flashcards
What are tissues based off and composed of?
based off structure of cells, composition non-cellular extracellular matrix and cell function
What are the 4 kinds
epithelial,connective, muscle and nervous
biopsy
removal of tissue for diagnostic purpose
autopsy
examination organs of dead body to determine death
what are the 3 types and functions of embryonic tissue?
ENDODERM- middle layer
-forms lining of digestive tracts MESODERM-middle layer. forms tissues such as muscle,bone,blood vessels. ECTODERM-outer layer, forms skin and neuroectoderm
what are important characteristics of Epithelial Cells?What areas of the body does it cover?
- consists of cells bound together closely. little or no intercellular space
- covers body surfaces and forms glands
- covers outside surface of body,lining digestive,respiratory and urogenital systems,heart, blood vessels
- exposed apical surface face and attached basal surface
- avascular( no blood vessels)- obtains nutrients by diffusion or absorption
What are the functions of epithelial tissue?
- provides physical protection. Epithelia protect exposed surfaces from dehydration,abrasion and destruction by chemical or biological agents.
- controls permeability:any substance leaving or entering body crosses epithelium. some impermeable, some permeable to large compounds such as proteins. hormones can affect transport of ions and nutrients. physical stress like callused hands from physical labour alter structures and properties of epithelia.
- secretes substances(pancreas) and absorbing substances(lining in small intestine)
what are the cell surface modifications?
Microvili-increase surface area absorption or secretion
Cilia-move materials across cell surface
How are epithelium Cells classified?
Number of cells and shape of cells
one layer of cell?
Simple epithelium-relatively thin. found in protected areas of body such as ventral body cavities,chambers heart, all blood vessels
define a stratified epithelium?
- 2 or more layers of cells
- height and shape may differ
- found areas of high mechanical or chemical stresses, such as surface area of skin and lining of mouth
what are the shapes of epithelial cells called ?
Cuboidal- equal height and width
squamous-flat,scale like
columnar-taller than wide
what are the functional characteristics of each cell?
SIMPLE- diffusion of gases, filtration of blood and secretion and absorptioin.
STRATIFIED-allows protection, patricularly against abrasion
Cuboidal and columnar- secretion or absorption, includes goblet cells which make and secrete mucus
Define functions of simple squamous epithelium?
- structure is single layer of flat cells
- functions include secretion,absorption,protection from friction,diffusion and filtration
Functions of a Simple Cuboidal Epithelium?
- provides limited protection
- secretion and absorption in kidney
- secretion in glands and choroid plexus
- movement mucus out of terminal bronchioles by ciliated cells
what is the structure and location of simple cuboidal epithelium
- structure single layer cube cells,some have cilia or microvilli.
- located kidney tubules, glands and ducts, choroid plexus of brain, lining of terminal bronchioles of lngs and surface ovaries.
Functions of Simple Columnar Epithelium?
- found areas where secretion and absorption occur
- ciliated cells help move particles out of bronchioles
- secretion by glands of intestine and stomach
- absorption by cells of intestine
structure and location of Simple Columnar Epithelium?
- single layer narrow,tall cells. some have cilia or microvilli
- located glands and ducts, bronchioles of lungs,auditorry tubes,uterus,uterine tubes,stomach,intestines,gallbladder,bile ducts and ventricles of brain
Functions of Stratified Squamous Epithelium?
- found where mechanical stresses severe
- protects against abrasion,caustic chemicals,water loss, infection
Structure and functions of Stratified Squamous Epithelium
- structure is multiple layers cells cuboidal in basal layer and progressively flatten towards surace. located mouth,throat,larynx,esophagues,anus,vagina, inferior urethra and cornea
- keratinized-skin, keratin protein tough and water resistant
- cells retain nucleus and cytoplasm however in keratinized cells they are dead.