Cytology and Histology Cells and Tissues. Section One Cell Theory

Cytology and HistologyCytology and Histology

Cells and Tissues

Section OneSection One

Cell Theory

Building Blocks of LifeBuilding Blocks of Life

• You can easily identify the picture of the leaf below. The appearance or structure of the leaf is different from the other objects.

• Are the microscopic “building blocks” of these objects just as different? Think about it!

Building Blocks of LifeBuilding Blocks of Life

• Although it is easy to identify the differences between living organisms with the naked eye, their microscopic structures are often very similar.

• The microscopic structures of different living organisms are the same because they are all comprised of cells.

• Cells act as building blocks to comprise all organisms.

InformationInformation

• The cell is the basic unit of structure in all living organisms:– Microscopic building blocks called cells comprise all

organisms, including plants, animals and microscopic organisms.

– Robert Hooke, in 1665, first used the term cell.– Some living organisms are unicellular (made of only

one cell).– There are many different kinds of cells that make up

plants and animals.

A Question…A Question…

• Why are living organisms made up of many different kinds of cells? Think about it!

• To answer this question, let’s look at several different types of cells.

Heart (Cardiac) Muscle CellsHeart (Cardiac) Muscle Cells

• Notice that these cells are long and thin and have many spaces between them. This structure makes it easier for the cells to expand and contract as the heart pumps blood.

Nerve CellNerve Cell• These cells can be as long as one meter. They are

specially designed to carry electrical and chemical signals from one part of the body to another. The long branches help the cell to communicate with other cells.

Skin (Epithelial) CellsSkin (Epithelial) Cells

• Note that these cells are very flat and can cover a large area. They provide an important protective function for an organism.

Vascular Stem CellsVascular Stem Cells

• These plant stem cells are narrow and tubular. They perform the special function of moving materials in a plant.


• The cell is the functioning unit of all living organisms.

• Living organisms can carry on their life processes because of the functioning of their cells.

• The particular kinds of structures in cells enable them to carry on their special functions.

• Is there another characteristic of living organisms that makes them different from nonliving things?

Living vs. NonlivingLiving vs. Nonliving

• Living things have cells that produce other cells. This is called reproduction.

• All cells come from previously existing cells.

ReviewReview

• Cells comprise all organisms• The cell is the basic unit of structure of an

organism.• Different types of cells make up organisms.• Different types of cells perform different

functions.• All cells come from previously existing cells.

Select The Letter Of The Correct Select The Letter Of The Correct Answer From The List Below:Answer From The List Below:

A. structure D. different B. organ E. identical C. cell F. function

1. The _________________ is the building block that comprises all organisms.

2. Each type of cell performs a different __________________.

3. The cell is an organism’s basic unit of __________________.

4. There are ________________ types of cells that comprise plants and animals.

1. The _________________ is the building block that comprises all organisms.

2. Each type of cell performs a different __________________.

3. The cell is an organism’s basic unit of __________________.

4. There are ________________ types of cells that comprise plants and animals.

Answers:Answers:

cell

function

structure

different

Section TwoSection Two

Exploring The Cell

Exploring The CellExploring The Cell

• Just as organs, like the heart or the lungs, make up an organism, organelles (microscopic working parts) make up cells.

• In this exercise we will examine a typical animal cell to discover the function of various cell organelles.



NucleusNucleus

• The nucleus is usually located near the center of the cell.

• It directs all life activities such as the manufacturing of chemicals that the cell and the organism require.

• The nucleus also directs the transport of the chemicals to other places in the cell.

NucleolusNucleolus

• The nucleolus is a dark body comprised of RNA and protein.

• Cell division involves the nucleolus. The nucleolus is most visible just before the cell divides.

• Protein synthesis also involves the nucleolus.

ChromatinChromatin

• Each cell of an organism contains the information to build the complete organism.

• DNA is the molecule that stores this hereditary information.

• DNA and protein make up the chromosomes found in the nucleus. Chromatin is a clump of DNA and protein.

Nuclear MembraneNuclear Membrane

• The nuclear membrane is the membrane envelope of the nucleus.

• It is connected with the endoplasmic reticulum and the cell membrane.

Endoplasmic ReticulumEndoplasmic Reticulum

• The endoplasmic reticulum is a series of membrane channels similar to the tunnels in a mine.

• It is the transportation system of the cell through which chemicals move from one part of the cell to another part.

Golgi BodiesGolgi Bodies

• Some membrane channels of the endoplasmic reticulum take on a special shape in the area of the nucleus.

• This is the Golgi complex. It is very prominent in cells that secrete cell products such as mucus.

CentrioleCentriole

• A microscopic framework comprised of thin filaments makes up the dense parts of the cytoplasm.

• Some of the filaments are organized into two cylinders called the centrioles.

• The centrioles make up the centrosome and are important in cell reproduction.

MitochondrionMitochondrion

• A double membrane folded into ridges comprises a mitochondrion.

• It supplies the energy needs of the cell by taking raw materials from food and changing them into chemical energy.

CytoplasmCytoplasm

• The cytoplasm is the fluid environment of the cell.

• The fluid is like water in some areas of the cell. In other areas it is thick.

• Cytoplasm often flows in a circular motion called cyclosis.

Cell MembraneCell Membrane

• The cell membrane, a lipid layer between two protein layers, encloses every cell.

• It is selectively permeable, allowing only some materials to pass into and out of the cell.

• It controls transport into and out of the cell.

RibosomeRibosome

• The ribosomes are the numerous tiny organelles lining the endoplasmic reticulum

• Ribosomes, comprised of ribonucleic acid (RNA) and protein, are important in manufacturing cell proteins.

CiliaCilia

• In some cells the centrosome reproduces and moves to the edge of the cell.

• It then gives rise to the fine hair-like structures called cilia.

• Sometimes, cilia become long and tail-like to form structures called flagella.

Pinocytic VesiclePinocytic Vesicle

• Pinocytic vesicles result from the cell membrane being pulled into the cell.

• Pinocytosis is the process by which vesicles release their contents into the cell.

LysosomeLysosome

• A lysosome is a sac-like organelle that contains enzymes to break down large food molecules into smaller ones.

• In the white blood cell, lysosomes become active when the cells engulf (surround and take in) bacteria.

• The lysosomes break open and digest the white blood cell as well as the bacteria.

Section ThreeSection Three

Cell Diversity

Structures Found In CellsStructures Found In Cells

Cell Structure Cell TypeCell Membrane Animal and PlantNucleus Animal and PlantLarge Vacuole Plant OnlyCell Wall Plant OnlyCytoplasm Animal and PlantChloroplast Plant OnlyCentrosome Animal OnlyMitochondria Animal and Plant

Cell WallCell Wall

• The cell wall is a rigid structure of nonliving material surrounding the cell membrane of plant cells. Made mostly of cellulose, it protects and supports plant cells and maintains their shape.

ChloroplastsChloroplasts

• Chloroplasts are organelles in the plant cell that contain the green pigment chlorophyll. Chlorophyll is important to plants for manufacturing food.

VacuolesVacuoles• Plant cell cytoplasm often contains large

round sacs called vacuoles. Most animal cells have only a few small vacuoles.

• Some unicellular organisms, like the amoeba, have specialized vacuoles such as food and contractile vacuoles.

CentrosomeCentrosome

• Centrosomes are small structures found in animal cells. Centrosomes contain centrioles that function during animal cell reproduction.

Quiz: Fill In The Blanks…Quiz: Fill In The Blanks…

Plant and animal cells have many organelles in common. However, a plant cell has a rigid _____________ comprised of cellulose that provides support. Some plant cells also contain a structure called a ____________ that is used to make food. A large storage ____________ can also be present. Animal cells can contain a small structure called a _____________ that is not found in plant cells.

cell wall

chloroplastvacuole

centrosome


• You now know about plant and animal cells.• There is a third group of organisms that have

characteristics of both plants and animals. They are the protists. They are usually microscopic and unicellular.

• A good example of a protist is the Euglena. It is a unicellular organism with chloroplasts, lacks a cell wall, moves by means of a flagellum, and can take in food as well as manufacture it.


• The protists generally include the following:– Protozoa– Most algae– Bacteria– Viruses– Fungi– Slime molds– Lichens

EuglenaEuglena

• The euglena resembles an animal since it lacks a cell wall and has a flagellum for movement. It has chloroplasts for photosynthesis, like a plant, and it can take in food like an animal.

FungiFungi

• Fungi include molds, mushrooms and yeasts. They do not use photosynthesis but live on dead or living organisms. They can be found as single cells or as filaments called hyphae. Fungi reproduce by spores.

• The common bread mold has hyphae that contain many nuclei in one large cell. The stem of the mushroom is a mass of hyphae that supports a cap. When the cap is ripe, it releases many spores.

BacteriaBacteria

• Bacteria are among the smallest unicellular organisms. They do not have a formed nucleus but possess a single ring-like chromosome in the cytoplasm.

• Most bacteria take in food. Some make their own food by photosynthesis using pigments other than chlorophyll. Most bacteria have a cell wall. Some bacteria are disease-producing while others are beneficial to man.

VirusesViruses

• Viruses are so small that they can only be seen through an electron microscope. A virus is made of DNA surrounded by a protein coat. They live only within other living cells where they force the cell to manufacture duplicates of the original virus.

• Some viruses called bacteriophages attack and destroy bacteria.

LichenLichen

• A lichen is a combination of a fungus and an alga that grow together. The alga produces food for itself and the fungus. The fungus holds water and protects the alga.

• This relationship between the alga and fungus is called mutualism since they grow together and help each other. Therefore, the lichen can live in hostile environments such as on bare rock.

AlgaeAlgae

• Many types of algae are unicellular green organisms. They contain the green pigment chlorophyll needed in photosynthesis to make their own food. Some algae are multicellular and contain other pigments. They live in water and moist places on land.

• Spirogyra is an example of a green algae made of single cells that attach to each other to form long spiral filaments.

AlgaeAlgae• Many types of algae are unicellular green

organisms. They contain the green pigment chlorophyll needed in photosynthesis to make their own food. Some algae are multicellular and contain other pigments. They live in water and moist places on land.

• Chlamydomonas is a unicellular fresh water algae with two flagella. Volvox is a hollow sphere of cells resembling the single chlamydomonas cells in the form of a colony.

ProtozoaProtozoa

• Protozoa are unicellular organisms that live free in water or as parasites in other organisms. They have no chlorophyll. We group them by the way they move.

• The amoeba is an example of a protozoan. The amoeba moves by pushing out the cell membrane in different directions to form pseudopods (false feet). It engulfs its food by surrounding it with pseudopods.

ProtozoaProtozoa• Protozoa are unicellular organisms that live

free in water or as parasites in other organisms. They have no chlorophyll. We group them by the way they move.

• The paramecium is an example of a protozoan that uses hair-like projections called cilia to move. They take in food through an oral groove that then forms a food vacuole within the cytoplasm. The food is then digested.

Slime MoldsSlime Molds• Slime molds follow several stages in their

life cycle. At one stage they are slimy masses of protoplasm. They are animal-like cells with flagella. At another stage they are like the amoeba. At still another stage they are like the molds and form spore cases for reproduction.

• Physarium is a good example of a slime mold. The plasmodium stage is a spreading mass. At another stage, it consists of amoeba-like cells.

ReviewReview• Plants, animals and protists are the three major groups of

organisms.• Protists are usually unicellular.• The protists include the following:

– Some Algae– Bacteria– Fungi– Lichens– Protozoa– Slime molds– Viruses

• Viruses are on the borderline of life since they reproduce only in other organisms.

Quiz: Fill In The Blanks…Quiz: Fill In The Blanks…

The three major groups of living organisms are the plants, animals and _____________. The third group is made up of organisms that have characteristics of both plants and animals. They are generally ______________ (single celled). The protists include the ______________, some algae, bacteria, viruses, fungi, slime molds and lichens. Among the protists, the group that is on the borderline of life is the ______________.

protists

unicellularprotozoa

viruses

Section FourSection Four

Tissues

Unicellular OrganismsUnicellular Organisms

• Unicellular organisms such as the paramecium can only grow to a certain size.

• Why do you think this is true? Think about it!• Here is a hint: Two of the most important life

processes are obtaining oxygen and getting rid of waste.

• All parts of a cell need oxygen. Poisonous waste materials must be disposed of by a cell.

What Limits Growth of What Limits Growth of Unicellular Organisms?Unicellular Organisms?

• Larger cells present a problem in getting oxygen to the very inner areas of the cell. The oxygen must move (diffuse) great distances from the cell membrane to get to some areas of a large cell.

• Waste must be removed from the cell. The larger the cell, the longer it takes to transport the waste to the outside environment. This is a serious problem for large cells.

VolvoxVolvox• Some unicellular organisms solve this problem by grouping

themselves in colonies. A good example of a colony is the protist Volvox.

• Hundreds of thousands of individual cells make up this hollow sphere. Each cell resembles a unicellular alga with two outward pointing flagella. The movement of the flagella causes the ball to spin forward.

• A thin strand of cytoplasm connects each cell to other cells. Cells at the posterior (hind) end of the ball created daughter colonies. Cells at the anterior (front) end have large eyespots.

• Certain cells of Volvox are specialized. Groups of similar cells work together for a special purpose, such as the cells making up the eyespots on Volvox. This is called specialization.


• In higher organisms, tissue is a group of similar cells that perform a special function. Muscle tissue is an example.

• Different types of tissues that function together as a unit comprise an organ. The stomach is an example of an organ.

• A group of organs that function together as a unit comprise a system. The digestive system is one example.

Select The Best Matching Select The Best Matching Choice:Choice:

Answer Column:A. Volvox specializationB. Group of organsC. Locomotion (movement)D. UnicellularE. VolvoxF. MuscleG. StomachH. Algae

Colony:Correct Answer: E Flagella:Correct Answer: C

Eyespot:Correct Answer: A

Tissue:Correct Answer: F Organ:Correct Answer: G

System:Correct Answer: B


• The cells of organisms are organized into different tissues adapted to do a special job.

• The cells making up a tissue are similar to each other and carry on the same function.

• The cells of different tissues differ from one another in structure and function.

• The organelles in all cells are the same. The differences in structure and function among the tissue cells are associated with their special organelles.

Nerve CellsNerve Cells

• Nerve cells can be very long and highly branched. They have a specialized cytoplasm for receiving stimuli and sending impulses.

• Nerve cells are specialized to transmit and receive nervous impulses. Each cell is well-suited to conduct information over long distances. An individual nerve cell can be as long as one meter. The connection between nerve tissue and muscle tissue is important for rapid movement.

Epithelial TissuesEpithelial Tissues

• Epithelial tissues form the inner and outer linings of organs. Groups of these cells may form glands. They are closely packed together.

• Epithelial cells are closely packed together with almost no spaces between the cells. Therefore, they provide a protective barrier. They often specialize to form gland cells that secrete substances to the surface of the tissue.

BloodBlood

• Plasma, red blood cells, white blood cells and platelets comprise blood. This liquid carries carbon dioxide, food and waste to various parts of an organism.

• Blood is a liquid matrix responsible for transporting materials. The red blood cells contain hemoglobin for the transport of oxygen. The white blood cells attack bacteria. The fragile platelets function in blood clotting.

CartilageCartilage

• You find cartilage on the ends of bones, the nose, the outer ear and the walls of the trachea (windpipe). The matrix (material between the cells) allows cartilage to bend.

• Cartilage is a dense, fibrous tissues with a rubbery material between the cells. Although cartilage is flexible and elastic, it can support weight. Some types of cartilage are more flexible than others.

Muscle TissueMuscle Tissue

• Muscle tissue forms the walls of the heart, the digestive system and the arteries. It is made of contractile fibers.

• The cells of muscle tissue have a great ability to contract. They are responsible for most movement in animals. Individual muscle cells are long and are bound together by connective tissue.

BoneBone

• Bone is made of interconnected cells in a stiff matrix that contains calcium and phosphorous salts. It is very rigid.

• Bone is saturated with inorganic salts (such as calcium carbonate and calcium phosphate) that give it strength. Bone is comprised of compact layers of hard material surrounding a central canal.

Connective TissueConnective Tissue

• Connective tissue attaches bone to bone (ligaments), muscle to bone (tendons) and skin to muscle. It contain fibers that provide strength.

• Connective tissue lines muscle fibers, attaches the skin to the underlying tissues, lines the heart, suspends the organs in their correct positions and forms a layer around blood vessels.

ReviewReviewTissue Type Function

Blood Transport, fight disease and clotting

Bone Rigid supportCartilage Flexible supportConnective Bind cells and organsEpithelial Protect, lubricate and

secreteMuscle MovementNerve Transmit information


Answer Column:A. Transmit informationB. Flexible supportC. Fight diseaseD. Store fats and oilsE. LubricateF. MovementG. ReproductionH. Rigid support

Nerve:Correct Answer: A Muscle:Correct Answer: F

Epithelial:Correct Answer: E

Cartilage:Correct Answer: B Bone:Correct Answer: H

Blood:Correct Answer: C

Section FiveSection Five

Testing Your Knowledge

This Is A Test of What You Have This Is A Test of What You Have Learned…Learned…

• There are 10 questions on this test.• Try to correctly answer all of the questions.• If you miss a question, watch the screen for

an explanation of the correct answer.


Answer Column:A. Supplies energyB. Comprises a centrioleC. Manufactures proteinD. Microscopic frameworkE. Directs cell activityF. Produces ciliaG. Transportation systemH. Digests bacteria

Ribosome:Correct Answer: CA ribosome is the cell organelle that manufactures protein. Ribosomes are the many small structures that line the endoplasmic reticulum.

Nucleus:Correct Answer: EThe nucleus directs all cell activities. It is usually located near the center in plant and animal cells from which it also directs the transport of chemicals to other cell parts.


Answer Column:A. Supplies energyB. Comprises a centrioleC. Manufactures proteinD. Microscopic frameworkE. Directs cell activityF. Produces ciliaG. Transportation systemH. Digests bacteria

Lysosome:Correct Answer: HLysosomes are sac-like organelles that contain enzymes which digest large substances. For example, white blood cells digest bacteria.

Mitochondrion:Correct Answer: AThe mitochondrion supplies energy to the cell by changing raw materials from food into chemical energy.

Select The Best Choice To Select The Best Choice To Complete Each Analogy:Complete Each Analogy:

An organ is to a multicellular organism as a(n) _____________ is to a cell.

A. systemB. muscleC. functionD. organelleE. tissue

organelle

Since an organ performs a specific task in a multicellular organism, the best analogy is an organelle that performs a specific task in a cell.

Select The Best Choice To Select The Best Choice To Complete Each Analogy:Complete Each Analogy:

A flagellum is to a cell as a ______________ is to a large multicellular organism.

A. muscleB. nerveC. ciliumD. boneE. cell

muscle

Since a flagellum’s function is to provide a cell with locomotion (movement), the best analogy is a muscle that also provides a large multicellular organism with movement.

Fill In The Blanks…Fill In The Blanks…

A(n) _____________ is the basic unit of structure in all organisms. It is comprised of small working parts, each of which is a(n) _____________. A group of similar cells that perform a specific function is a(n) _____________. Different groups of these similar cells that function as a unit comprise a(n) ______________. These, in turn, make up the systems of a large multicellular organism.

cell

organelle

tissueorgan

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Cytology and Histology Cells and Tissues. Section One Cell Theory