Animal Tissue Flashcards
what is tissue?
group of similar cells along with intercellular substances with in them performing same function
classification of animal tissue
4 types : epithelial - simple and compound epithelium
connective - loose, dense, specialised C.T.
muscular- skeletal, smooth , cardiac muscles
neural- neaurons and neuralgia cells
epithelial tissue
: has a free surface either facing body fluid or the outside environment
: provides lining
: compactly packed cells with little intercellular spaces
: 2 types - SIMPLE AND COMPOUND
SIMPLE epithelium
single layer of cells
functions as linking of body cavities , ducts , tubes
3 types - squamous , columnar, cuboidal
squamous epithelium
single layer of flattened cells
irregular boundaries
+nt in walls of blood vessels , air sacs of lungs
forms diffusion boundary
cuboidal epithelium
: single layer of cube like cells
: +nt in PCT , ducts of glands .
: main function absorption and secretion
: in PCT epithelium has a microvilli .
columnar epithelium
: single layer of tall and slender cells
: nuclei at the base
: free surface has microvilli
: +nt in the lining of stomach and intestine .
: helps in absorption and secretion
Ciliated epithelium
: free surface of columnar and cuboidal epithelium having cilia on it.
: helps move the mucus or particles in a specific direction over the epithelium
: +nt in inner surface of hollow organs like bronchioles and fallopian tube .
pseudo stratified epithelium
: it is a single layer but appears to be multilayered .
: +nt in trachea and bronchi .
epithelium of blood vessel is cd
endothelium
glandular epithelium
on the basis of specialised secretions from columnar and cuboidal cells , these are named as glandular epithelium which are further divided into 2 types unicellular and multicellular
unicellular ( goblet cells of alimentary canal)
multicellular ( salivary glands )
glands on pouring secretions
on this basis , there are 2 types of glands exocrine and endocrine
exocrine : those with ducts or tubes , eg mucus , ear wax, milk, saliva , digestive enzymes etc.
Endocrine : these are ductless , secretes hormones , directly into the fluid bathing the gland
compound epithelium
it is multilayered ,
limited role in secretion and absorption
main role is providing support and protection against mechanical and chemical stresses
+nt in dry surface of skin, moist surface of buccal cavity , pharynx , inner lining of salivary glands and pancreatic ducts .
Junctions
all cells are held together by little intercellular spaces .
there exists 3 types of junction
Tight : helps prevent leakage
Adhering : acts like cement to keep neighbouring cells together .
Gap junctions : facilitate the cells to communicate with each other by connecting cytoplasm of adjoining cells which help transfer of ions , small molecules and sometimes big molecules
CONNECTIVE TISSUE
: it is most abundant tissue and widely distributed in the body of complex animals .
: named connective tissue bcoz of functions of linking and supporting
: all C.T. except blood secrete fibres like structural proteins cd elastin or collagen which provide strength, elasticity and flexibility
also secrete modified polysaccharides which accumulate btw cells and fibres act as matrix
3 types : loose , dense , specialised C.T.
Loose C.T. :
has cells and fibres loosely arranged in semi fluid ground substance .
: of 2 types
areolar
adipose
areolar c.t. :
areolar : +nt beneath the skin ,s supports as framework for epithelium
contains fibroblast [ that produce and secrete fibres] , macrophages and mast cells .
adipose C.T.
adipose cells is another type of loose C.T. located mainly beneath the skin . the cells of tissue are specialised to store fats , excess of nutrients which are not used immediately and are converted and stored as fats in it .
Dense C.T. :
fibres and fibroblast are compactly packet in it
this further has 2 types : dense regular and irregular depending on the orientation of fibres
regular dense C.T. :
in regular collagen fibres are arranged in rows btw parallel bundles of fibres
tendons [ bone to muscle ]
ligament [ bone to bone] are examples of this tissue
irregular dense C.T. :
has fibroblast and many fibres [mostly collagen] that are oriented differently . +nt in skin .
SPECIALISED C.T. :
cartilage , bone and blood are diff types of C.T.
Cartilage :
it is solid , pliable , and resists compression . cells of this tissue [chondrocytes] are enclosed in small cavities within the matrix secreted by them . most of the cartilage in vertebrates embryo are replaced by bones in adults . +nt in tip of nose , outer ear joint , bones of vertebral column , limbs , and hands in adults .
Bone :
it is hard , non pliable , ground substance rich in calcium salts which give bone its strength . main tissue that provide structural frame work to the body . it supports softer tissue and organs . cells [osteocytes ] +nt in space cd LACUNAE. limb bones , long bones serve as weight bearing function . attach with skeletal muscles to bring movements. bone marrow in some bones cause red blood cells production ..
