epithelial tissue Flashcards
what are the 4 types of body tissues
epithelial, connective, muscle, nervous
what fills the spaces between cells
intercellular matrix
what is the function of connective tissue
supports and binds other tissues (bone, blood, lymph)
what is the function of epithelial tissue
provides a covering i.e skin, linings of the various passages inside the body
what is the function of muscle tissue
includes striated muscles that move the skeleton, and smooth muscles such as the muscles that surround the stomach
what is the function of nerve tissue
made of nerve cells and used to carry messages around the body
where can you find epithelial tissue
covering all body surfaces, lining body cavities and hollow organs and are the main tissue in glands
how are epithelial cells arranged
tightly packed with little intercellular matrix
what are epithelial cells connected to?
connective tissue via a non-cellular basement membrane
what is the basement membrane
thin, pliable sheet-like type of extracellular matrix which provides cell and tissue support. also acts as a platform for complex signaling. it sits between epithelial tissues such as mesothelium and endothelium and the underlying connective tissue
what are the three factors which classify epithelial cells
shape, stratification, specialisation
list the 4 shapes of epithelial cells
squamous, cuboidal, columnar, transitional
list the three types of stratification
simple, stratified, pseudostratified with cilia
describe the squamous shape
flat with an irregular flattened shape
describe the cuboidal shape
a cube shape, nuclei are in the centre
describe the columnar shape
taller than they are wide, nucleus closer to the base
describe the transitional cells
cells that line organs that can stretch such as the bladder and uterus
explain the simple stratification
single layer of cells
explain the stratified stratification
more than one layer of cells, can withstand a lot of stress, only one layer touches the basement membrane
explain the pseudostratified with cilia stratification
only a single layer of cells but the position of the nuclei gives the impression that it is stratified
where are simple cuboidal epithelium found
glandular tissue and in the kidney tubules
where are simple columnar epithelium found
stomach and intestines
where are pseudostratified columnar epithelium found
lining the respiratory tract and some of the tubes in the male reproductive tract
give three types of specialisations of epithelium
glandular, keratinised, cilated
describe glandular epithelium
specialised to secrete and produce substances- two types, exocrine and endocrine
what is an exocrine gland
a gland that discharges its secretion onto the surface of the epithelium
what are the three types of exocrine gland?
merocrine gland, apocrine gland and holocine gland
what is a merocrine gland
a gland that secretes substances by the plasma membrane resulting in the release of the secretion and loss of cell membrane, i.e sweat glands, salivary glands
what is an apocrine gland
a gland that secretes a shedded portion of their cytoplasm i.e mammary glands
what is a holocrine gland
glands that secrete by shedding entire cells from the lining of a duct, i.e sebaceous glands
what is an endocrine gland?
releases secretions i.e hormones into surrounding tissues which then diffuse into the bloodstream for distribution to other regions of the body
what are keratinised cells
contain keratin, found mostly in the skin bu also found in the mouth and nose providing a tough, impermeable barrier. they are flat and dead cells, with no nucleus or organelles
what are ciliated cells
have apical plasma membrane extensions composed of micro-tubules capable of beating rhythmically to move mucus or substances through a duct. these are common in the respiratory tract and lining of the oviduct
