Animal Tissue

Question 1

what is tissue?

Answer 1

group of similar cells along with intercellular substances with in them performing same function

Question 2

classification of animal tissue

Answer 2

4 types : epithelial - simple and compound epithelium
connective - loose, dense, specialised C.T.
muscular- skeletal, smooth , cardiac muscles
neural- neaurons and neuralgia cells

Question 3

epithelial tissue

Answer 3

: 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

Question 4

SIMPLE epithelium

Answer 4

single layer of cells
functions as linking of body cavities , ducts , tubes

3 types - squamous , columnar, cuboidal

Question 5

squamous epithelium

Answer 5

single layer of flattened cells
irregular boundaries
+nt in walls of blood vessels , air sacs of lungs
forms diffusion boundary

Question 6

cuboidal epithelium

Answer 6

: single layer of cube like cells
: +nt in PCT , ducts of glands .
: main function absorption and secretion
: in PCT epithelium has a microvilli .

Question 7

columnar epithelium

Answer 7

: 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

Question 8

Ciliated epithelium

Answer 8

: 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 .

Question 9

pseudo stratified epithelium

Answer 9

: it is a single layer but appears to be multilayered .
: +nt in trachea and bronchi .

Question 10

epithelium of blood vessel is cd

Answer 10

endothelium

Question 11

glandular epithelium

Answer 11

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 )

Question 12

glands on pouring secretions

Answer 12

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

Question 13

compound epithelium

Answer 13

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 .

Question 14

Junctions

Answer 14

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

Question 15

CONNECTIVE TISSUE

Answer 15

: 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.

Question 16

Loose C.T. :

Answer 16

has cells and fibres loosely arranged in semi fluid ground substance .
: of 2 types
areolar
adipose

Question 17

areolar c.t. :

Answer 17

areolar : +nt beneath the skin ,s supports as framework for epithelium
contains fibroblast [ that produce and secrete fibres] , macrophages and mast cells .

Question 18

adipose C.T.

Answer 18

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 .

Question 19

Dense C.T. :

Answer 19

fibres and fibroblast are compactly packet in it
this further has 2 types : dense regular and irregular depending on the orientation of fibres

Question 20

regular dense C.T. :

Answer 20

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

Question 21

irregular dense C.T. :

Answer 21

has fibroblast and many fibres [mostly collagen] that are oriented differently . +nt in skin .

Question 22

SPECIALISED C.T. :

Answer 22

cartilage , bone and blood are diff types of C.T.

Question 23

Cartilage :

Answer 23

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 .

Question 24

Bone :

Answer 24

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 ..

Question 25

Blood :

Answer 25

fluid C.T. containing RBC, WBC, PLATELETS .
Circulating fluid helps in transferring various substances .

Question 26

MUSCLE TISSUE :

Answer 26

each muscle has long , cylindrical fibres made up of fibrils and myofibrils . these muscles shorten [contract] and lengthen [expand] and return to uncontracted state in a coordinated fashion . its Ian function is in active movement of all body parts .

Question 27

SKELETAL MUSCLES :

Answer 27

tissue is closely attached to skeletal bones . in a typical muscle ; s.a. biceps , striated [stripped] skeletal muscle fibres are bundled together in parallel fashion . a sheath of tough C.T. encloses several muscle fibres

Question 28

SMOOTH MUSCLES

Answer 28

taper at both ends [ fusiform]
don’t show striations.
cell junction hold them together bundled together in a sheath .
wall of blood vessels , intestine , stomach contains such tissue .
involuntary
can’t be directly controlled just by thinking .

Question 29

CARDIAC MUSCLE :

Answer 29

contractile tissue only +nt in heart .
involuntary
never gets fatigue
cell junction fuse P.M. together and make them stick together .
Communication junction [ INTERCALATED DISC ] at some fusion point allows cells to contract as a unit . i.e. when one cell receives signal to contract , others to get to contract .

Question 30

NEURAL TISSUE :

Answer 30

greatest control over body’s responsiveness .
neurons are the excitable cells ;
neuroglia cell constitute rest of the neural system , protect and support neurons . neuroglia make more than one half of the volume .
electrical distrubance when a neutron is stimulated travels through P.M. , then arrives at neutron ending ,or output zone , triggers events that may cause stimulation or inhibition of adjacent neurons and other cells .