This document provides information on the four basic tissue types - epithelial, connective, muscle and nervous tissue. It describes each tissue type in detail, including their characteristic roles and functions. For epithelial tissue, it discusses the different classifications including simple and stratified epithelium as well as glandular tissues. It also covers the key components and functions of connective, muscle and nervous tissues.

1. Tissue Level of Organization
By
Yogeshwary M. Bhongade
Assistant Professor
Kamla Neharu College of Pharmacy, Butibori, Nagpur

2. Tissues
• Tissues are groups of similar cells that have a common function.
• The four basic tissue types are epithelial, muscle, connective, and
nervous tissue. Each tissue type has a characteristic role in the body:
Tissue
Epithelial Tissue
Covers the bodysurface
and lines bodycavities
Connective Tissue
Supports and protects body
organs.
MuscularTissue
Provides movement.
Nervous Tissue
Provides a means of rapid
internal communication by
transmitting electrical
impulses

3. Epithelial Tissue
• It is made up of tightly opposed cells
• They form the covering or lining to the free surface of the body
• Rest on basement membrane
• Seperate epithelial tissues from other tissues
Epithelial
Tissue
Membranous
Epithelium
Glandular tissues

4. Functions of the Epithelium
• Epithelia tissue forms boundaries between different environments, and nearly all
substances must pass through the epithelium. In its role as an interface tissue,
epithelium accomplishes many functions, including:
• Covers the body surface and lines body cavities (Pericardial, Peritonial, Plural
Cavitiesand Cardiovasculat System also tined by epithelial tissues. Body tubes are
lined by epithelial tissues)
• Protection for the underlying tissues from radiation, desiccation, toxins, and
physical trauma.
• Absorption of substances in the digestive tract lining with distinct modifications.
• Regulation and excretion of chemicals between the underlying tissues and the
body cavity.
• The secretion of hormones into the blood vascular system. The secretion of
sweat, mucus, enzymes, and other products that are delivered by ducts come from
the glandular epithelium.
• The detection of sensation.

5. Characteristics of Epithelial Layers
• Epithelial tissue is composed of cells laid out in sheets with strong cell-to-
cell attachments.
• These protein connections hold the cells together to form a tightly
connected layer that is avascular but innervated in nature.
• The epithelial cells are nourished by substances diffusing from blood
vessels in the underlying connective tissue.
• One side of the epithelial cell is oriented towards the surface of the tissue,
body cavity, or external environment and the other surface is joined to a
basement membrane.
• The basement layer is non-cellular in nature and helps to cement the
epithelial tissue to the underlying structures.

6. Epithelial Tissue
• Epithelial tissues are identified by both the number of layers and the
shape of the cells in the upper layers.
• There are eight basic types of epithelium: six of them are identified
based on both the number of cells and their shape; two of them are
named by the type of cell (squamous) found in them.
• Epithelial tissue is classified based on the number of cells, the shape of
those cells, and the types of those cells.

7. Types Of Epithelial Tissues
Membranous
Epithelium
Shape
Squamous Cuboial Columnar
Layers
Simple
Epithelium
Simple
Squamous
Simple Cuboial
Simple
Columnar
Stratified
Epithelium
Stratified
Squamous
Stratified
Cuboial
Stratified
Columnar
Psudostratifies
Epithelium

8. Types of Simple Epithelial Tissue
1. A simple squamous epithelium -
• It is a single layer of flat cells in contact with the basal lamina (one of
the two layers of the basement membrane) of the epithelium.
• This type of epithelium is often permeable and occurs where small
molecules need to pass quickly through membranes via filtration or
diffusion.
• Flat, nucleous located near the upper surface gives these cells
appearance of fried egg.
• Found in CVS, Respiratory System, Kidney(Nephron)

9. 2. Simple cuboidal epithelium
• It consists of a single layer cells that are as tall as they are wide. The
important functions of the simple cuboidal epithelium are secretion
and absorption.
• This epithelial type is found in the small collecting ducts of the
kidneys, pancreas, and salivary glands, surface of ovaries.
• They are cube or hexagone shape with central, round nucleus.
• These cells produces secretions (Secretions) or absorb substances
(digestive fluid)

10. 3. Simple columnar epithelium-
• It consist of a single layer of cells that are taller than they are wide.
• This type of epithelia lines the small intestine where it absorbs nutrients
from the lumen of the intestine.
• Simple columnar epithelia are also located in the stomach where it
secretes acid, digestive enzymes and mucous.
• Tall with an oval nucleous near the basement membrane.

11. Types of Stratified Epithelial Tissue
1. A stratified squamous epithelium-
• It consists of squamous (flattened) epithelial cells arranged in layers
upon a basal membrane.
• Only one layer is in contact with the basement membrane; the other
layers adhere to one another to maintain structural integrity.
• In the deeper layers, the cells may be columnar or cuboidal.
• Found in Oral Cavity, Vagina and oesophagous.

12. 2. Stratified cuboidal epithelial Tissue
• It is a rare type of epithelial tissue composed of cuboidally shaped
cells arranged in multiple layers.
• They protect areas such as ducts of sweat glands, mammary glands,
and salivary glands.

13. 3. Stratified Columnar epithelial Tissue
• Stratified columnar epithelium is a rare type of epithelial tissue
composed of column-shaped cells arranged in multiple layers.
• It is found in the conjunctiva, pharynx, anus, and male urethra.

14. Transitional epithelium
• Transitional epithelium is a type of stratified epithelium.
• This tissue consists of multiple layers of epithelial cells which can
contract and expand in order to adapt to the degree of distension
needed.
• Transitional epithelium lines the organs of the urinary system and is
known here as urothelium.

15. Glandular tissues
• The glandular tissue are a mixture of both endocrine (ductless, hormones
are secreted into the blood) and exocrine (have ducts, hormones are
secreted onto surfaces) glands.
• The exocrine glands are covered in the respective topics. For example
sweat glands are covered in the section on skin.
Glandular
tissues
Unicellular Multicellular
Endocrine
Gland
Exocrine
Gland

16. Connective tissue
• Connective tissue is the tissue that connects, separates and supports all
other types of tissues in the body.
• Like all tissue types, it consists of cells surrounded by a compartment
of fluid called the extracellular matrix (ECM).
• Connective tissue, group of tissues in the body that maintain the form
of the body and its organs and provide cohesion and internal support.
• The connective tissues include several types of fibrous tissue that vary
only in their density and cellularity, as well as the more specialized
and recognizable variants—bone, ligaments, tendons, cartilage, and
adipose (fat) tissue.

17. Functions of Connective Tissue
• Bind togather, support and strenthen body tissue
• Protect and insulate internal organ.
• Transport.
• Store energy in addipose or fat tissue
• Immune response

18. Types of connective tissue
Connective
tissue
Cell
Ground
Substances
Fluid

19. Cells
Connective
Tissue
Fibroblast Macrophages Plasma cells Mast cell Adipocytes Leukocytes

20. Ground Substances
• Present between cell and fibre
• It is in the form of fluid, semifluid or gelateneous or calcified
• Support cell and bind them togather
• Store wathe and organic substances given below.
Connective
Tissue
Polysachharides
Hyaluronic Acid
Chondroitin
Sulphate
Dermatan
Sulphate
Keratin Sulphate
Proteins
Adhesive protein-
Fibronectin

21. Muscle Tissue
• Muscle tissue is a specialized tissue found in animals which functions by
contracting, thereby applying forces to different parts of the body.
• Muscle tissue consists of fibers of muscle cells connected together in sheets
and fibers.

22. Function of Muscle Tissue
• Muscle tissue functions as a single unit, and is often connected to the same
nerve bundles. A nerve impulse traveling from the brain or another outside
signal tells the muscle to contract. The nerve impulse is transferred almost
instantaneously to all the nerve cells in the muscle tissue, and the entire
muscle contracts.
• At the cellular level, each muscle cell has a complex of proteins containing
actin and myosin. These proteins slide past one another when the signal to
contract is received.
• The filaments are connected to the ends of the cells, and as they slide past
one another, the cell contracts in length. A single cell can contract up to 70%
in length, which shortens the entire muscle when contraction happens.
Muscle tissue can be used to move bones, compress chambers, or squeeze
various organs.

23. Types of Muscle Tissue
Skeletal Muscle Tissue
• Skeletal muscle tissue is a type of striated muscle, meaning clear bands can
be seen in it under a microscope.
• These tiny light and dark bands are sarcomeres, highly organized bundles of
actin, myosin, and associated proteins.
• These organized bundles allow striated muscle to contract quickly and
release quickly. Muscle tissue is attached to the bones through tendons,
which are highly elastic portions of connective tissue. Many muscles may
seem to control a single appendage, but in reality each one only controls one
small aspect of movement. Skeletal muscle tissue can be controlled
voluntarily, by the somatic nervous system. The other types of muscle are
controlled mainly by the involuntary or autonomous nervous system.

24. Cardiac Muscle Tissue
• While the striations in skeletal muscle tissue are even and parallel,
complex and branching striations are seen in cardiac muscle tissue.
• While the striations are hard to see in this image, the branching nature of
the cells is easy to pick out.
• The branching is caused by the connection of cardiac muscle cells to one
another. The cells are connected via intercalated discs. These junctures
help cardiac muscle to contract as one and provide a rapid and
coordinated contraction to move blood.

25. Smooth Muscle Tissue
• Unlike cardiac and skeletal muscle tissue, smooth muscle tissue has no
striations. The fibers of myosin and actin in smooth muscle fiber is not
nearly as organized as in the other types of muscle tissue. In smooth
muscle, the contractions are not quick and rapid but rather smooth and
continuous. Smooth muscle is found surrounding many organs, blood
vessels, and other vessels used for transporting fluids. The smooth
muscle can contract to apply a force on organ. This can be used to move
blood or food throughout their respective systems. Smooth muscle is
recognizable from its lack of striations and unbranching nature in image
(b) below.

26. Nervous Tissue
• Nervous tissue is the term for groups of organized cells in the nervous
system, which is the organ system that controls the body's movements,
sends and carries signals to and from the different parts of the body, and
has a role in controlling bodily functions such as digestion