The Cell TheoryThe Cell Theory

Chapter 2Chapter 2

The CellThe Cell

All living things are made of cells.All living things are made of cells.Cells are the smallest living unit of life.Cells are the smallest living unit of life.Each cell performs the necessary Each cell performs the necessary

functions to sustain life.functions to sustain life.Cells can replicate themselves. Cancer Cells can replicate themselves. Cancer

occurs when cells replicate occurs when cells replicate haphazzardly.haphazzardly.

Cellular function is carried out by Cellular function is carried out by organelles.organelles.

Cellular reactions are mediated Cellular reactions are mediated (controlled) by ENZYMES. (controlled) by ENZYMES.

Enzymes speed up chemical Enzymes speed up chemical reactions.reactions.

All the chemical reactions in the body All the chemical reactions in the body make up its METABOLISM.make up its METABOLISM.

There are 10 organelles that you are There are 10 organelles that you are responsible for.responsible for.

Plasma MembranePlasma Membrane

Outer covering of the cell.Outer covering of the cell.Also called the PLASMALEMMA.Also called the PLASMALEMMA.Separates the intracellular (inside) Separates the intracellular (inside)

fluid and the extracellular (outside) fluid and the extracellular (outside) fluid.fluid.

Double layer of lipids (fat) with Double layer of lipids (fat) with protein molecules between the layers.protein molecules between the layers.

Polar Head (like water)Polar Head (like water)Non-polar tails (do not like water)Non-polar tails (do not like water)Proteins within the membrane. They Proteins within the membrane. They

give support to the membrane and give support to the membrane and prevent it from collapsing.prevent it from collapsing.

Carbohydrates are attached to the Carbohydrates are attached to the integral proteins. These form the integral proteins. These form the GLYCOCALYX.GLYCOCALYX.

The glycocalyx is a sticky coat that The glycocalyx is a sticky coat that allows the cell to bind to other cells.allows the cell to bind to other cells.

The glycocalyx also serves as a The glycocalyx also serves as a marker.marker.

i.e.: certain antibiotics recognize i.e.: certain antibiotics recognize the the

glycocalyx and attach to the glycocalyx and attach to the cell.cell.

Functions of the Plasma Functions of the Plasma MembraneMembrane

Allows entry into the cell Allows entry into the cell (Endocytosis)(Endocytosis)

Phagocytosis – cell eatingPhagocytosis – cell eating

Pinocytosis – cell drinkingPinocytosis – cell drinking

Receptor-Mediated - Receptor-Mediated - hormoneshormones

Allows movement out of cells Allows movement out of cells (Exocytosis)(Exocytosis)

CytoplasmCytoplasm

Cytosol is a gel like substance which Cytosol is a gel like substance which holds all the internal cellular holds all the internal cellular organelles.organelles.

Contains ions, water, and enzymes.Contains ions, water, and enzymes.

THE ORGANELLESTHE ORGANELLES

Perform all the cellular functions.Perform all the cellular functions.

““Little Organs”Little Organs”

MITOCHONDRIAMITOCHONDRIA

Power plant of Power plant of the cellthe cell

Produces energy Produces energy

RIBOSOMERIBOSOME

2 parts that make proteins.2 parts that make proteins.

RNA

Ribosome

ENDOPLASMIC RETICULUMENDOPLASMIC RETICULUM

Subway system of the cell.Subway system of the cell.Network of membrane-walled tubes Network of membrane-walled tubes

that twist through the cytoplasm.that twist through the cytoplasm.ROUGH E.R. – have ribosomes ROUGH E.R. – have ribosomes

attached.attached.SMOOTH E.R. – do not have SMOOTH E.R. – do not have

ribosomes attached.ribosomes attached.

GOLGI APPARATUSGOLGI APPARATUS

Stacks of disk shaped membranes.Stacks of disk shaped membranes.

SortSort

Package proteinsPackage proteins

ProcessProcess

LYSOSOMESLYSOSOMES

Sacs containing digestive enzymes Sacs containing digestive enzymes that can break down almost all types that can break down almost all types of biological materials.of biological materials.

PEROXISOMESPEROXISOMES

Contain oxidases (use oxygen to Contain oxidases (use oxygen to neutralize aggressive compounds neutralize aggressive compounds known as free radicals).known as free radicals).

Free radicals can damage cellular Free radicals can damage cellular proteins, membranes, and DNA if left proteins, membranes, and DNA if left to accumulate.to accumulate.

CYTOSKELETONCYTOSKELETON

System of complex rods that run System of complex rods that run throughout the cytoplasm.throughout the cytoplasm.

MicrotubulesMicrotubulesMicrofilamentsMicrofilaments

CENTROSOMECENTROSOME

Contains a matrix and an inner pair Contains a matrix and an inner pair of centrioles which are important in of centrioles which are important in cellular division.cellular division.

NUCLEUSNUCLEUS

Membrane bound organelle which is Membrane bound organelle which is the control center for all cellular the control center for all cellular activity..activity..

Contains DNA – produce instructions Contains DNA – produce instructions for protein synthesis.for protein synthesis.

Contain chromosomesContain chromosomes

Produce ribsomes in the nucleolusProduce ribsomes in the nucleolus

Related Clinical TermsRelated Clinical Terms

NECROSIS – cellular death due to NECROSIS – cellular death due to disease or injury.disease or injury.

HYPERTROPHY – increase in size.HYPERTROPHY – increase in size.

i.e. Muscle cells become i.e. Muscle cells become hypertrophic in response to exercise.hypertrophic in response to exercise.

nucleus

Cell membrane

Endoplasmic reticulum

mitochondria

Golgi apparatus

TISSUESTISSUES

Chapter FourChapter Four

OBJECTIVES for TissuesOBJECTIVES for Tissues

Be able to list the four basic tissue Be able to list the four basic tissue types and give examples of each.types and give examples of each.

Describe the functions of each tissue Describe the functions of each tissue type.type.

Describe the cellular components of Describe the cellular components of each tissue type.each tissue type.

Describe and identify the Describe and identify the morphology of epithelial tissue types.morphology of epithelial tissue types.

TissuesTissues

Cells do not operate independently.Cells do not operate independently.Related cells work and operate Related cells work and operate

together in organized groups.together in organized groups.

The bottom line:The bottom line:

Tissues are clubs of cellular Tissues are clubs of cellular organization.organization.

Four Types of TissuesFour Types of Tissues

1. Epithelial Tissue1. Epithelial Tissue

2. Connective Tissue2. Connective Tissue

3. Muscle Tissue3. Muscle Tissue

4. Nervous Tissue4. Nervous Tissue

EPITHELIAL TISSUEEPITHELIAL TISSUE

Covers the body surface Covers the body surface

oror

Lines a body cavityLines a body cavity

Epithelial TissueEpithelial Tissue

Occurs at the interface of two Occurs at the interface of two different environments.different environments.

i.e. The epidermis is between the i.e. The epidermis is between the inside and the outside of the body.inside and the outside of the body.

Protects the body by detecting Protects the body by detecting harmful stimuli.harmful stimuli.

i.e. Receptors for pain are found i.e. Receptors for pain are found within the skin.within the skin.

SecretionSecretion

release of molecules from the cellrelease of molecules from the cell

AbsorptionAbsorption

bringing small molecules into the bringing small molecules into the cell.cell.

Ion transport – moves ions (charged Ion transport – moves ions (charged molecules) across a membrane.molecules) across a membrane.

The epithelium filters fluids that The epithelium filters fluids that cross the barrier.cross the barrier.

Characteristics of Epithelial Characteristics of Epithelial TissueTissue

1. Cellularity 1. Cellularity – composed almost entirely – composed almost entirely of cells.of cells.

2. Specialized Contacts – 2. Specialized Contacts – connects connects adjacent cells.adjacent cells.

gap junctions, tight junctions, gap junctions, tight junctions, desmosomesdesmosomes

3. Polarity 3. Polarity – under surface called the – under surface called the “basement membrane”.“basement membrane”.

4. Avascular 4. Avascular – lacks blood vessels. – lacks blood vessels. Receives nutrients through the Receives nutrients through the underlying connective tissueunderlying connective tissue

5. 5. RegenerationRegeneration – replaces lost/dead – replaces lost/dead cells quickly.cells quickly.

Shapes of Epithelial TissueShapes of Epithelial Tissue

Simple Epithelium – one layerSimple Epithelium – one layerStratified Epithelium – more than one Stratified Epithelium – more than one

layerlayerSquamous – cells are wider than tallSquamous – cells are wider than tallCuboidal – cells are just about as tall Cuboidal – cells are just about as tall

as wideas wideColumnar – cells are taller than wide.Columnar – cells are taller than wide.

CONNECTIVE TISSUECONNECTIVE TISSUE

Types of connective tissueTypes of connective tissue

FatFat

CartilageCartilage

Ligaments and TendonsLigaments and Tendons

BoneBone

BloodBlood

CollagenCollagen

Functions of Connective TissueFunctions of Connective Tissue 1. Support and bind other tissues. 1. Support and bind other tissues.

(tendons, ligaments)(tendons, ligaments) 2. Hold body fluids (ground substance).2. Hold body fluids (ground substance). 3. Defend against infection3. Defend against infection - mast cells- mast cells - macrophages- macrophages - plasma cells- plasma cells - neutrophils- neutrophils 4. Store nutrients as fat. 4. Store nutrients as fat.

Muscle TissueMuscle Tissue

Brings about body movement.Brings about body movement. Moves by shortening.Moves by shortening. Three Types:Three Types:

1. skeletal – pulls on long bones. Striated.1. skeletal – pulls on long bones. Striated.

2. cardiac – only in the heart.2. cardiac – only in the heart.

3. smooth – no visible striations. Found in 3. smooth – no visible striations. Found in walls of hollow visceral organs such as walls of hollow visceral organs such as digestive system, urinary organs, blood digestive system, urinary organs, blood vessels, and uterus. Mostly involuntary.vessels, and uterus. Mostly involuntary.

Nerve TissueNerve Tissue

Uses electrical impulses to transport Uses electrical impulses to transport information.information.

Can RegenerateCan Regenerate

Identify the Following:

Epidermis

Dermis

Hair follicle

Subcutaneous fat

Pore