Epithelial tissue

tissues are group of cells which may or may not be similar in structure but are specialized to perform special function. study of tissue is called histology

aka covering tissue.
• it is a typed of tissue which covers the inner and outer part of organs. its characters
1)cells are compactly packed 2) absence of inercellular space. 3)cells lie on the basement membrane. 4)avascular
5) presence of nerve endings. 6)joined together by cemeting of an carbohydrate derivate

•composed of single layer of cells. •rounded centrally placed nucleus •composed of thin flat hexagonal •cells found in lining of buccal cavity. •lining of coelom kidney blood vessel alveoli of lungs

suboidal shaped centrally placed nucleus cells at basal membrane found in liming of kidney thyroid gland sweat gland salivary gland testis gut and ovary

-tall pillar like structure large oval elliptical nucleus present ineard basal end.
- found in the inner linning of stomach and other organs.
eg inner lining of goblet cells of stomach gastric glands, intestial galnds uterine wall

keratinised.
• presence of keratin
•rough resisnant and horny
• resistant to friction acts as waterproof
•dies subsequently resistant to bacterial invasion present in the hair nail claw skin etc non-keratinizied
• absence of keratin smooth helps in lubirctaion during chewing and sallowing
• not resistant to friction
• do not act as waterproof
•keeps the tissue moist found in esophagus buccal cavity and wet surfaces tissue is alive

•presence of cuboidal cells in the upper layer and squamous and columnar in the lower layer
• present in the linning if salivary gland , sweat gland pamcreatic gland female urethra

presence of columnar celss in the upper layer and squamous and cubiidal in the germinative layer •cilliated
• present in
•intestinal lining
•lining of uterus
•lining if pharynx
•lining of urethra
•linning if anus
•salivary gland
•epiglottis

•presence of cillia on free surface •function is to propel mucus away from lungs to prevent infection
• and in fallopian aid the transportation of ovum from ovary to uterus.
•found in trachea and bronchi of pulmonary and fallopian tube if reproductive system

•composed of modification of stratified squamous and straitifed columnar
• 4 layers also called plastic epithelium due to presence of highly elasctic cells
• epidermis or superficial layer cells are flat large and quadrilateral •second layer is pear shaped
• found urinary bladder uterus and urethra

unicellular eg goblet cells single cells scattered in columnar cells multicelluar eg sweat and gastric gland formed of many cuboidal cells

endocrine - ductless secrete hormone and pour secretion directly in blood vessel eg thyroid gland pituatary gland exocrine - have duct secrete enzyme pour secretion through duct eg salivary sweat gland heterocrine - secrete noth enzyme and horomone eg pancreatic and gonad

holocrine (eg sebaceous gland) secretion are discharged by rupture of plasma apocrine ( eg mammry gland) secretion are discharged by rupture of apex or few secretary cells merocrine ( eg salivary gland) secretion are discharged by diffusion or exocytosis

-formed of columnar cell
-they go deep but do not reach upon the free surface
-they rest upon basal membrane
-found in the urinary duct, bronchi and trachea

-loose connective tissue
-jelly like transparent matrix fibers and cells
fibers include
white fiber ☃️
presence of collagen fibers
long unbranched and thick
provide tensile strength and elasticity and help in reapir of injury
yellow fiber ✨
elastin fiber
provides elasticity due to presence of elastin fiber
long branched and interconnected to form a network
cells ❣️
*fibrocytes/ - secrete matrix and fibers(both yellow and white)
/macrophages/-phagocytic in function
englufs bacteria toxc substances and damaged cells
*mast/- produce heparin and histamine
heparin prevents clotting of blood in the injured vessel
histamine causes dilation of blood vessel which is an inflammatory response to the infection or injury
*adipocytes- fat storing cells
*function is to pack tissues and combat with toxic substances released by pathogen

-composed of fat storing cells called adipocytes
has less or no fibers
peripherally placed nucleus
two types
white adipose
-due to large number of adipocytes
found in adult humans
yellow adipose
-due to large number of blood vessel
found in developing feotus and infant