introduction to tissues-human body is made up of 4 basic tissues- connective tissues, epithelium tissue, nervous tissue, muscular tissue--biological tissues is a collection of interconnected cells that perform a similar function and an embryological origin with similar structure , types of tissues , microscopic diagram, diagrams of tissues, epithelial tissue and types, connective tissue , its components and types Types of tissues with characteristic's and distribution regions

1. ANANYA GIRISH BABU
LECTURE

2. Objectives:
 To know the different types of tissues, present in the human body.
 To study the cells, fibers and ground substance constituting connective tissue.
 To identify the different types of glands, present in the body.

3. TISSUES OF THE BODY
• A group of cells having similar origin, structure and function is called a tissue.
• A tissue is a group of cells that usually have a common embryonic origin and function together to carry out
specialized activities
• Types: There are four types of basic tissues in the body according to their structure and function :
1. Epithelial tissue
2. Connective tissue
3. Muscular tissue
4. Nervous tissue
• Cartilage and bone are specialized connective tissues.

4. EPITHELIAL TISSUE
• It is a layer of cells, which covers the external surface (skin) or lines the internal surface of gastrointestinal, respiratory, and
urogenital tract.
Functions
• Protection: It protects the body surface from drying or bacterial invasion.
 Transport: Mucous and particulate matters are carried to epithelial surface. Fluid may pass through the cell.
 Secretion: The cells secrete the product synthesized, either to the lumen or blood. [space within the tube tract, cavities]
 Excretion: May excrete metabolic waste a products.
 Absorption: It absorbs essential substances from the lumen of the GIT and kidney tubules (Where it is called reabsorption).
 Lubrication: Peritoneum[serous membrane in abdomen], pleura and pericardial epithelium serve this function.
 Sensory: In the skin (touch sensation), nasal mucosa (smell sensation) and tongue (taste sensation), it serves as sensory organ.

6. Types of epitheliums
Epithelium is classified into
 simple
 pseudostratified
 stratified varieties

7. Simple epithelium
Simple squamous epithelium Simple cuboidal: Simple columnar:
• Irregular flat cells with height less
than width.
• Distribution:
a. Alveoli of the lungs.
b. Bowman's capsule and loop of Henle
of kidney.
c. Mesothelium lining the and
pericardial cavities.
d. peritoneum, pleura
e. Endothelial cells lining blood
vessels.
• Height and width are nearly equal
and nuclei are central in position
• Distribution:
a. Thyroid follicles
b. Ducts of many gland
c. Surface of the ovary
• Height of the cells is greater than
width, nuclei are elongated and
placed towards the base
• Distribution:
a. small bronchi and bronchioles,
b. uterine tube
c. Efferent ductules of the testis
• Non ciliated simple columnar :
distributed – lining of
gastrointestinal tract from stomach
to rectum, gall bladder
Single layer of cells resting on a basement membrane

10. Pseudostratified columnar epithelium
• Single layer of cells resting on the basement of the membrane
• Some cells are shorter and do not reach the lumen, while tall cells reach the lumen.
• The nuclei of the cells therefore lie at different levels. This gives the impression of stratification (false
stratification).

11. Pseudostratified
columnar epithelium
Pseudostratified non
ciliated
Distributions:
Male urethra
Auditory tube
Pseudostratified ciliate
Distribution:
Upper part of
respiratory tract

12. Stratified epithelium
• These are made up of many layers of cells
• They found in areas which are subjected to friction
1 Stratified squamous non keratinized • Epithelium made up of many layers of cells basal cell resting on the basement
membrane and columnar or low cuboidal
• Superficial cells are squamous and flat hence called stratified squamous
epithelium
Distribution : epithelium lining of mouth, esophagus, anal canal, vagina
2 Stratified squamous keratinized • The superficial layer consist of non living cells with keratin in their cytoplasm
• They are tough and water resistant
Distribution: epidermis of the skin
3 Stratified cuboidal epithelium • Consist of few layer of cuboidal cells
Distribution : duct of sweat gland
4 Stratified columnar epithelium • It consist of 2 or more layer of cells
• Basal layers are seen as polyhedral and superficial cells are columnar
Distribution: male urethra

13. Transitional epithelium
• These are stratified epithelium which having 3 or 4
layers of cell
• Deepest cell columnar or cuboidal , middle layers are
polyhedral or pear shape, cell surface are umbrella
shaped cells
• Distribution : renal pelvic, ureter, urinary bladder

14. Glandular epithelium
• The epithelial cells are specialized to perform secretary function. Such epithelial cell in groups
constitute glands (single epithelial cell can also be a gland-unicellular).
• There are 2 types of glands
1. Exocrine gland
2. Endocrine gland

16. EXOCRINE GLANDS ENDOCRINE GLANDS
• When the secretion form the gland is poured through
duct system they are called exocrine gland
e.g.: salivary gland
• Depending upon the nature of secretion it may classified
as
a. mucous gland [secrete mucopolysaccharides]
b. serous gland [watery in nature rich with proteins]
• These glands are ductless and pour their secretions
directly to the blood stream, these secretions are called
hormones

17. Connective tissue
• Connective tissue has formed elements[ fibers and cells] and amorphous substance or ground substance
COMPONENTS OF CELL
1. Cells – 7 cells are found in connective tissue
2. Fibers- connective tissue fibers are of 3 types

18. fibroblast collagen fibres
macrophages reticular fibres
Plasma cells elastic fibres
Mast cells
Pigment cells
Reticular cells
Fat cells/ adiposities
Components
of
connective
tissue
Cells Fibers

19. Fibers – collagen fibers
• In fresh state they are in white color so they are also known as
White fibers [ individual diameter 1-12 °µm]
• It contain protein called collagen
• Collagen fibers run in straight or wavy but individual fibers
don’t not branch [ bundles can branch]
• Collagen fibers formed and maintained by fibroblast
• Depending on diameter they are classified as
1. Type I :[diameter about 250nm] they found in tendons,
ligaments, bones and meninges
2. Type II :[diameter about 20-100nm] found in cartilages
3. Type III: they are also called reticular fibers
4. Type IV : form the basement membrane of the epithelium

20. Reticular fibers
• Similar to collagen fiber type III in chemical structure
• They are thin fibers of network or a reticulum which shows branching but they don’t run in bundle
• They forms the skeletal framework of the lymphatic system
Distribution –
• Basement of epithelial tissue
• Walls of blood vessels
• Lymphatic organs

21. Elastic fibers
• They are thin and highly elastic, they are branched
don’t form bundle
• In bulk they form in yellow so known as yellow
fibers
• They can be stretched and return to the original state
• They are made up of proteins called elastin
Distribution
• Loose connective tissues
• Wall of blood vessels
• Capsule of glands

22. Cells
1. Fibroblast • Each cells is flattened or fusiform shaped and centrally placed nucleus
• They are responsible for the formation of fibers such as elastic, reticular and collagen
• Help in healing wound
2. Macrophages • less numerous than fibroblast
• Their cytoplasm contain hydrolytic enzyme
• Phagocytic function
• They are 2 type- fixed[ attached to reticular fibers] and wandering [free and become ovoid]
3. Plasma cells • These cells are numerous in mucous and submucous coat in the gut
• Round in shape and accentually placed nucleus
• These cells produce antibodies in defense mechanism of body
4. Mast cell • Cells are rounded in shape with centrally placed nucleus
• Present in fibrous capsule of the liver, along the blood vesicles, beneath the mucosa of
alimentary and respiratory tract
• They secrete heparin which is an anticoagulant
• And also produce histamine which causes allergic reaction

23. 5. Pigment cells • Present in iris and choroid of the eye
6. Reticular cell • Present in reticular connective tissue
• Produces reticular fibers
• Phagocytic in nature
7. Fat cells /adipocytes • Polygonal in shape with accentually placed nucleus
• Cytoplasm have large amount of fat and they are numerous in adipose tissue

25. Connective
tissue
Loose
connective
tissue
Areolar tissue
Myxomatous
tissue
Adipose
tissue
Dense
connective
tissue
Cartilage Bones

26. Areolar tissue Adipose tissue Myxomatous tissue Reticular tissue
• Common connective
tissue where collagen
and elastic fiber are
loosely arranged and
their Ground substance
is semifluid in nature
• Plenty of macrophages
and fibroblast are
present
• This is an aggregation
of fat cell
• It is abundant in female
especially in pectoral
region and gluteal
region
• Matrix consist of mucoid
substance with few
collagen fiber
• It also shows star shaped
fibroblast
• It contain network of
reticular fibers and
contain specialized
fibroblast called
reticulocytes
Distribution : between
muscles, vessels and nerve
Space between the organs
Distribution : bone
marrow, Subcutaneous
tissue ,Bony orbit
• Those tissues are present
in umbilical cord and
vitreous body of eye
• Those are present in
lymphatic organ and
bone marrow

27. -loose-myxomatous-connective-tissue- Reticular connective tissue-diagram