All living organisms are made of cells and cell products. Cells vary in size, shape, and function. The basic unit of structure and function in the human body is the cell. Cells have a membrane, cytoplasm, and organelles that allow them to carry out functions. Tissues are groups of cells that work together to perform a specific function. The four main types of tissues are epithelial, connective, muscular and nervous tissue. Epithelial tissue covers and protects the body, connective tissue binds and supports other tissues, muscular tissue forms muscles, and nervous tissue transmits signals in the body.

1. Introduction to cells
and tissues
Mr. Sachin Parsekar

2. Introduction to cells and tissues
• All living organisms are made of cells and cell products.
• Cells are the smallest living subunits of organism such as a human being
• Microorganisms, such as amoebas and bacteria, are single cells that function
independently.
• Human cells, however, must work together and function interdependently.
Human body depends upon the contributions of all of the different kinds of
cells
• Human cells vary in size, shape, and function. Most human cells are so small
they can only be seen with the aid of a microscope

3. Cells
• Cells is the basic or smallest unit or
part of living organism
• Cells are known as building blocks of
life.
• The human cells are consist of water,
protein , and nucleic acid.
• Every cells of body is able to take in
food, get rid of waste and grow.
• Most of the cells can reproduce also.

4. Cell structure and functions of cells
• Early biologists saw cells as simple membranous sacs
containing fluid and a few floating particles.
• Cells vary in their shape, size, color and functioning.
• Cells are unicellular and multicellular
• Unicellular: which are made up of one cell. ( bacteria)
bacteria)
• Multicellular: which are made up of many cell (
( human).
 red blood cells and nerve cells are specialized cells.
Bacteria

5. Shapes of cells
• Cells shape and size which are related to
its need or job it does.
• E.g.
1. Thin Muscle cells can contract to do
work.
2. Long nerve cells can relay the
massages throughout body.
3. Outer skin layer skin forms a protective
cover over our body. Flat shape helps
them to cover a large area.

6. Basic composition of cells
• Cell membrane
• Cytoplasm
1. Endoplasmic reticulum
2. Mitochondria
3. Golgi apparatus
4. Lysosomes
5. Ribosomes
• Nucleus
• Cilia and flagella

7. Cell membrane
• Thin covering called the cell membrane enclosed the cell.
• Cell membrane form both the outer boundary of the cell itself
and the boundary of most of the internal cell.
• It separate inner contain of cell from outer environment.

8. Cytoplasm
• Cytoplasm is the part of a cell between its
membrane and nucleus.
• The cytoplasm is the gel-like fluid inside the
cell.
• It provides a platform upon which other
organelles can operate within the cell.
• Cytoplasm contain cytoplasmic
organelles.

9. • Endoplasmic reticulum : it
forms of network of canals which
serve as channel for the
transport of materials from one
part of cell to another.
• it is vast system in cytoplasm
outside nucleus.

10. • Mitochondria : mitochondria is small
throughout the cytoplasm.
• Membrane( biological molecules or
particles) contain many folds.
• Fold contain enzymes which convert food
into energy.
• It is also known as power house of cell.
• It transfer ATP (Adenosine triphosphate) to
place where required.

11. • Golgi apparatus: Golgi Apparatus
consist of stock of flat membrane
sacs nears nucleus.
• It is present in concentration form
which are required for digestion.
• thus sacs process protein and other
substances.
• it regulates the movements of fluid in
the cells and push out of product
from cell.

12. • Lysosomes: It is small membrane
enclosed sacs.
• That capable of breaking down protein
and lipids.
• It contain digestive enzymes that break
down protein, fat and carbs.

13. • Ribosomes : every cells contains thousands of ribosomes
• It is small spherical molecules attaches to endoplasmic reticulum.
• Scattered throughout the cytoplasm.
• Ribosomes are molecules that makes protein.
• It is also called protein factory.

14. Nucleus
• The nucleus is control system that direct the activities of the cells.
• A nucleus membrane surrounds the nuleous and separate it from the cytoplasm.
• It contains two important structure.
1. Chromosome: it contains DNA (deoxyribonucleic Acid). DNA makes ups genes.
It is basic unit of heredity.
2. Nucleoli: nucleic hels in formation of ribosomes.

15. • Functions of Nucleus:
1. The nucleus is the cells control system
2. It direct cells growth and controls all
the activities that go on within the
cells.
3. It stores genetic information.
4. It also control genetic information.

16. Cilia and flagella
• Cilia are tiny brush like hairs.
• Cilia are generally short and in great numbers.
• Cilia are found in respiratory tract where they move the mucus and traps foreign
particles and keep longs safe from unwanted foreign substance.
• A flagellum or flagella is a long, whip-like structure that helps some single
celled organisms move.

17. Cell division
• When cell is formed is small.
• It grows after digesting food.
• growth of cell is limited.
• After reaching a certain critical size it divides to
form two cells.
• New cells are required for growth of an
organism and replace dead body cells.
Some cells in our body keeps on dividing throughout our life. In human body about 30 lakh blood
cells die and are replaced each second. Skin cells also keep diving. Some cells in brain cannot
replace once the die. Becouse body can heal injuries in all parts of body except nervous system

18. Tissues
• Next level organism after cells is tissues.
• Tissues are groups of cells that have a similar structure
and act together to perform a specific function.
• Each type of tissues in an organ performs a special
function
• E.g.
1. blood three types of cells,
2. whereas muscles tissues have only one type of cells.
3. Muscular part of intestine consist of group of muscles cell
that makes muscle tissues. Muscular tissue contract and
expand to allow the food to move forward.

19. Types of tissues
1. Epithelial tissue
2. Connective tissues
3. Muscular tissue
4. Nervous tissue

20. Epithelial tissue
• The main function of epithelial
tissue is to protect the body.
• It cover whole body and all the
organs.
• It also cover the internal surfaces
of organs such as mouth,
oesophagus, stomach, intestine,
lungs, trachea, blood vessels and
urinary bladder

21. • Epithelial cells haves different shapes depending on their function and
location.
• Cuboidal
• Flat
• Columnar ( tall column)
• The individual cells are tightly packed with no space between them,
that makes the epithelial tissue an ideal protective tissue.

22. Functions of epithelial tissue
1. In stomach the cells of tissue forms a glands
which secrete digestive juices.
2. In intestine inner surface absorb the food.
3. In skin it removes waste by excreting them in
the form of sweat.
4. This tissue which forms inner lining of nose,
bronchi and lungs secret mucus, which keep
these organs moist and traps dust particles
and harmful bacteria

23. Connective tissues
• Connective binds two or more
other tissue or organ.
• It fills up the space between
organs of body. It provides
support and give shape to the
body
• All connective tissue consist of
jelly like ground substance called
matrix.
• Various connective tissue have
different types of cells and fibers in
them.

24. Example of connective tissues
1. Bone is hardest connective tissue. Its hardness because of the
calcium and other minerals in the matrix. It forms skeletal which
support the body.
2. Cartilages is soft connective tissue consisting of cartilages cells. Its
matrix consist if a clear glassy material, which makes the tissue tough
but flexible. External ear is made of cartilages.
3. Blood is a liquid connective tissues. It has red blood, white blood cells
and platelets. Matrix is filles with a liquid called blood plasma. This
tissues helps in transport of digested food, respiratory gases and
waste in the body

25. Muscular tissue
• Muscular tissue forms the muscles in the body.
• The muscular tissues are found in every part of body.
• It makes up one-third of the body weight.
• Muscular tissue is collection of large number of muscle cells.
• Muscle fibbers are bound together by connective tissue.
• Most of attached to to bones of the skeleton.

26. Types of muscle tissue
1. Voluntary or striped muscles.
2. Involuntary or smooth muscles.
3. Cardiac or heart muscles.

27. Nervous tissue
• Nervous tissue consist of nerve cells or
neurons.
• A nerve cells is made up of the cells
body. Which contain the nucleolus and
long
1. Afferent nerve tissue :(sensory)
transmit messages to brain ( eyes,
skin, )
2. Efferent nerve tissue : (motor) relay
information from brain to organs.

28. Thank you