Biological tissue is a collection of interconnected cells that perform a similar function within an organism. In other words, it is a group of cells working together mainly inside an organ.Epithelial cells cover or line all body surfaces, cavities and tubes. So, These are called covering epithelia.Epithelial cells form the functional units of secretory glands. So, These are called glandular epithelia.

1. TISSUES

2. Definitionof Tissues
Biological tissueisa collection ofinterconnected
cells thatperforma similarfunction within an
organism.
Inotherwords,itisa group of cells working
together mainly inside an organ.

3. Classification of Tissues
Humanbody iscomposed of
4basic types oftissue:
•Epithelial tissue
•Connective tissue
•Muscular tissue
•Nervous tissue

4. Origin of Tissue
A fertilized egg divides to produce 3 primary germ cell
layers. These layers differentiate to form the tissues of the
body.

5. Epithelial Tissue
Epithelialcells cover orline all body surfaces, cavities and
tubes.So,Theseare called covering epithelia.
Epithelialcells formthefunctional unitsofsecretory glands.
So,Theseare called glandular epithelia.

6. General Characteristic
 Closely attached to each other forming a protectivebarrier.
 Always has one free (apical) surface open to outside the bodyor
inside (cavity) an internal organ.
 Always has one fixed (basal) section attached to underlying
connective tissue.
 Has no blood vessels but can soak up nutrients from bloodvessels
in connective tissue underneath.
 Can have lots of nerves in it (innervated).
 Very good at regenerating (fixing itself). i.e. sunburn, skinned
knee.

7. Functions
 To protect the tissues that lie beneath it
from radiation, desiccation, toxins, invasion by pathogens,and
physical trauma.
 The regulation and exchange of chemicals between the underlying
tissues and a body cavity.
 The secretion of hormones into the blood vascular system, and/or
the secretion of sweat, mucus, enzymes, and other products thatare
delivered by ducts glandularepithelium.
 To provide sensation.
 Absorbs stomach and intestinal lining (gut).
 Filters the kidney.

8. Classification of Epithelia
According tothickness
 “simple” - one cell layer
 “stratified”–morethanone layer of cells (whichare
named according totheshape of thecells inthe
apical layer)
According toshape
 “squamous”–widerthan tall
 “cuboidal” –as tallas wide
 “columnar” - taller than wide

10. Simplesquamous epithelium
Description: Singlelayer of
flattened cells withdisc-shaped
central nuclei and sparse
cytoplasm; thesimplestofthe
epithelia.
Function:Passivetransportofgases
and fluids.
Location:Alveoli oflungs,lining
body cavities (mesothelium),lining
blood vessels (endothelium)

11. Simplecuboidal epithelia
Description :Single layer of
cubelike cells withlarge,
spherical central nuclei.
Function:Secretion and
absorption.
Location: Kidney tubules;
ducts and secretory portions
ofsmall glands; ovary
surface.

12. Simplecolumnar epithelia
Description: Singlelayer of tall
cells withround tooval
nuclei.
Types: (i)Ciliated columnar
epithelia.
(ii)Non-ciliated
columnarepithelia.
Function: Absorption;
secretion of mucus,
Enzymes and
other
substances.
Location: Digestive tract, gall
bladder etc.

13. Stratifiedsquamous epithelia
Description:
Multilayered, surface cell are
squamous, basal cells are
cuboidal and divided
constantly.
Function: Protection.
Location: Oral
cavity, cervix, anal canal.

14. Stratifiedcuboidal epithelia
Description:Generally two
layers ofcube-like cells.
Function: Protection.
Location: Large ducts ofsweat
glands, mammary glands,
and salivary glands.

15. Stratifiedcolumnar epithelia
Description:
Multilayered, superficial cells
elongated and columnar.
Function:Protection;
secretion.
Location: Rareinthebody;
small amountinthemale
urethra.

16. Pseudo stratifiedcolumnar
epithelia
Description: Single cell layered,
all cell attach tothebasement
membrane butnotall reach the
free surface. Nuclei at varying
depth.
Function: Secretion of mucus,
propulsion of mucus by ciliary
action.
Location: Linesof trachea.

17. Transitionalepithelia
Description:Characterized by
domelike cells thatare neither
squamous norcolumnar. The
formofthecellschanges.
Function:Stretchingand
protection.
Location: Bladder and partof
urethra.

18. Connective Tissues
Thetissuesthatconnect the differentpartsof the
body together are called connective tissues.

19. General characteristic
 The intercellular material is maximum where as the
cellular component is minimum.
 Unlike the other tissues, (e.g. epithelium, muscle and
nerve) which are formed mainly by cells, the major
constituent of connective tissue is ECM (Extra-cellular
matrix).
 Possesscells, fibersand groundsubstances.

20. Basic Functions
 Supportand binding ofother tissues
 Holding body fluids
 Defending thebody against infection
macrophages, plasma cells, mastcells, WBCs
 Storingnutrientsasfat

21. Classification of connective
tissues

22. Connective tissueproper :
Loose CT; Areolar
Description: Gel like matrix with
all three fiber types ; cells:
fibroblasts, macrophages, mast
cells, and whiteblood cells.
Function: Its macrophages
phagocytize bacteria ; plays
important role in inflammation ;
holds and conveys tissue fluid.
Distributed under
of body; surrounds
Location:
epithelia
capillaries.

23. CTproper :Loose CT;Adipose
Description: Matrix as in areolar,
but very sparse; closely packed
adipocytes, orfatcells , have
nucleus pushed to the side by
large fat droplet.
Function: Provides reverse food
fuel; insulates against heat loss;
supportsand protects organs.
Location: Under skin; around
kidneys and eyeballs; within
abdomen; in breasts.
Fat droplets
Nucleus

24. CTproper: Loose CT; reticular
Description: Network of reticular
fibers in a typical loose ground
substance; reticular cells lie on
the network.
Function: Fibers form a soft internal
skeleton that supports other cell
types including white blood cells,
mastcells, and macrophages.
Location: Lymphoid organs(lymph
nodes, bone marrow, and
macrophages.

25. CTproper: dense CT; Irregular
Description: Primarily irregularly
arranged collagen fibers; some
elastic fibers; major cell type is
the fibroblast.
Function:Elasticityand structural
support.
Location: Dermis of the skin;
submucosa of digestive tract and
joints.
Collagen
fibers

26. CTproper: dense CT; Regular
Description: Primarily parallel
collagen fibers; a few elastin
fibers; major cell type is the
fibroblast.
Function: Attaches muscles to
bones and bones to bones.
Location: Tendons and in most
ligaments.

27. Cartilage: Hyaline
Description: Amorphous but firm
matrix; chondroblasts produce
the matrix and when mature lie
in lacunae.
Supports and
resists compressive
Function:
reinforces;
stress.
Location: Forms most of the
embryonic skeleton; ends of
long bones; cartilages of nose.

28. Cartilage: Elastic
Description:Similartohyaline
cartilage, butmore elastic
fibersin matrix.
Function:Maintainstheshape
and allows flexibility.
Location: Supportstheexternal
ear(pinna).

29. Cartilage : Fibrocartilage
Description : Collagen fibers
are predominant ; matrix is
as hyaline butless firm.
Function: High
strength,
tensile
absorb
compressive shock.
Location: Intervertebraldisc;
discs ofknee joint.

30. Bone
Description: Hard, calcified
matrix containing many
collagen fibers. Very well
vascularized.
Function: Bone supports and
protects; provides levers for
the muscles to act on; stores
calcium and other minerals
and fat; bone marrow is the
siteof blood cell formation.
Location: Skeleton.

31. Blood
Description:Liquidconnective
tissue,red and whiteblood
cells influid matrix.
Function:Transportrespiratory
gases, nutrients,wastesand
other substances.
Location: Intheblood vessels.

32. Muscle Tissue
 Muscle is one of our 4 tissue types and muscle tissue
combined with nerves, blood vessels, and various
connective tissues.
 Muscles are quite complex and as we’ll find out, they
are a marvel ofboth biology and physics.

33. General characteristics
1. Excitability
 Theability toreceive and respond toa stimulus
 Inskeletal muscle, thestimulusisa neurotransmitter
(chemical signal) release by a neuron (nerve cell).
 In smooth muscle, the stimulus could be a
neurotransmitter,a hormone, stretch,pH, Pco2, or
Po2.
 In cardiac muscle, the stimulus could be a
neurotransmitter,a hormone, orstretch.
Theresponse isthe generation of an electrical impulse that
travelsalong theplasma membrane of themuscle cell.

34. 2. Contractility
 Theability toshortenforcibly whenadequately
stimulated.
 Thisisthedefining property ofmuscletissue.
2. Extensibility
 Theability tobe stretched(Extended)
4. Elasticity
 Theability torecoil and resumeoriginal length
afterbeing stretched.

35. Functions
 Movement
 Locomotion
 Maintains posture
 Produces heat
 Facial expressions
 Pumps blood
 Peristalsis

36. 3TypesofMuscle Tissue

37. Skeletal Muscle Tissue
Description:Longstriated cells
withmultiplenuclei.
Function:Contraction for
voluntary movements.
Location: Inskeletal muscle.

38. SmoothMuscle Tissue
Description:Long, spindle-
shaped cells, each witha
single nucleus.
Function:Propulsionof
substancesalong internal
passageways.
Location: Inholloworgans(e.g.
stomach)

39. Cardiac Muscle tissue
Description:
Branching, striated cells
fused at plasma
membranes.
Pumping of
the circulatory
Function:
blood in
system.
Location: Wallof heart.

40. Nerve Tissue
Byfarthemostcomplex tissueinthehumanbody is
nerve tissue.
Formed by a network of more than 100 million nerve
cells, assistedby many more glial cells.
Each neuron has, on an average , at least a
thousand interconnection with other neurons forming
a very complex nervous system.

41. Functions
 Regulates&controlsbody functions
 Generates &transmitsnerveimpulses
 Supports,insulatesand protects impulse
generating neurons.

42. Composition of Nerve Tissue
Thenerve tissueiscomposed oftwo elements:
1. Thenerve cell orneuron
2. Theneuroglia

43. Neuron
Description: Neurons are
branching cells; cell processes
that may be quite long extend
from the nucleus-containing cell
body.
Function: Transmit electrical
signals from sensory receptors
and to effectors(muscles and
glands) that control their
activity.
Location: Brain, spinal cord and
nerves.

44. Glial cells
Glia carry nutrients, speed
repair, provide myelin for
axons, support the blood-
brain barrier, and may form
their own communication
network. They are also
involved in neurogenesis.

45. References:
1.Gray's Anatomy, 40thEdition
By Susan Standring, PhD, DSc,FKC
2.http://www.highlands.edu/academics/divisions/scipe/biology/labs/rome/
histology
3.http://krupp.wcc.hawaii.edu/BIOL100L/powerpoint/tissues
4.http://www.iteachbio.com/Anatomy-Physiology/BodyTissues
5.http://www.lavc.edu/instructor/watson_k/docs/Tissues
6.http://www.nakedscience.org/mrg/Anatomy%20Unit%204%20-
%20Tissue%20Types

46. Thank
You ALL