Tissues Flashcards
epithelial tissue
covers surfaces, cells strongly connected to each other and these define the function of the tissue, it separates tissue also and has some secondary functions eg forms glands
connective tissue
connects and supports one part of the body to another, extracellular matrix and fluid that defines function not cells, eg blood, bone, adipose
muscle tissue
contracts and shortens, long thin cells, packed with contractile apparatus, 3 types- smooth, skeletal, cardiac
nervous tissue
communication from one part of body to another, neutrons are the cells, they receive impulses and transmit to others, integrate information,
endothelium
thin membrane that lines the inside of the heart and blood vessels made of epithelial cells
how do epithelial cells maintain surface coverage
tight junctions (occluding), gap junctions, desmosomes and cell to extracellular matrix junctions, no contact inhibitions
epithelia lie on a
basement membrane made of basal lamina and reticular lamina. held on by hemidesmosomes
secondary roles of epithelia
movement- cilia, absorption- microvilli
types of epithelia
squamous, cuboidal, columnar, transitional (only in urinary bladder), pseudostratified columnar (trachea)
Exocrine glands
secrete into tubes circles down then up still connected to surface. can be tubular or acinar OR tubuloacinar (compound). mucus glands or serous glands
Endocrine glands
secrete into blood, cuts off from surface
methods of exocrine secretion
merocrine gland (vesicles get secreted out by exocytosis through lumen) , apocrine gland (pinched off) , holocrine gland (whole gland disintegrates and gets secreted eg hair follicle)
myoepithelial cells
squeeze the acini
abnormal functions of epithelial cells
over or under proliferation, over or under secretion, loss of cilia
eg pituitary gland secreting growth hormone - gigantism or dwarfism if over or under proliferated
mucus glands in uterine tube- thick mucus, chlamydia
what makes up the extracellular matrix that is needed for connective tissue
fibres-collagen and elastin (rope like), ground substance (jelly like), tissue fluid
collagen
formed by fibroblasts, inelastic but flexible, reticulin (type III)
elastic fibres
consists of elastin, yellow, can stretch, found in sheets
types of connective tissue
loose, dense regular, dense irregular
loose connective tissue cells
permanent cells- fibroblasts, adipocytes, macrophages, mast cells, undifferentiated mesenchyme cells. transient cells- white blood cells
dense regular
strong, straight eg tendon
dense irregular
elastic, move in more than one directions eg dermis of skin
abnormal functions of connective tissue
blood too many white blood cells- leukaemia bone- osteoporosis
what is cancer in connective tissue called
sarcoma
what is cancer in epithelial tissue called
carcinoma
