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 haphazzardly.occurs when cells replicate 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 reactions.Enzymes speed up chemical 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) fluid Separates the intracellular (inside) fluid
and the extracellular (outside) fluid.and the extracellular (outside) fluid. Double layer of lipids (fat) with protein Double layer of lipids (fat) with protein
molecules between the layers.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 give Proteins within the membrane. They give
support to the membrane and prevent it support to the membrane and prevent it from collapsing.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 allows The glycocalyx is a sticky coat that allows the cell to bind to other cells.the cell to bind to other cells.
The glycocalyx also serves as a marker.The glycocalyx also serves as a marker.
i.e.: certain antibiotics recognize the i.e.: certain antibiotics recognize the
glycocalyx and attach to the cell.glycocalyx and attach to the cell.
Functions of the Plasma Functions of the Plasma MembraneMembrane
Allows entry into the cell (Endocytosis)Allows entry into the cell (Endocytosis)
Phagocytosis – cell eatingPhagocytosis – cell eating
Pinocytosis – cell drinkingPinocytosis – cell drinking
Receptor-Mediated - hormonesReceptor-Mediated - hormones 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 organelles.holds all the internal cellular 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 the Power plant of the cellcell
Produces energy Produces energy
ENDOPLASMIC ENDOPLASMIC RETICULUMRETICULUM
Subway system of the cell.Subway system of the cell. Network of membrane-walled tubes that Network of membrane-walled tubes that
twist through the cytoplasm.twist through the cytoplasm. ROUGH E.R. – have ribosomes ROUGH E.R. – have ribosomes
attached.attached. SMOOTH E.R. – do not have ribosomes SMOOTH E.R. – do not have ribosomes
attached.attached.
GOLGI APPARATUSGOLGI APPARATUS
Stacks of disk shaped membranes.Stacks of disk shaped membranes.
SortSort
Package proteins made in the ERPackage proteins made in the ER
ProcessProcess
LYSOSOMESLYSOSOMES
Sacs containing digestive enzymes that Sacs containing digestive enzymes that can break down almost all types of can break down almost all types of biological materials.biological materials.
PEROXISOMESPEROXISOMES
Contain oxidases (use oxygen to Contain oxidases (use oxygen to neutralize aggressive compounds known neutralize aggressive compounds known as free radicals).as free radicals).
Free radicals can damage cellular Free radicals can damage cellular proteins, membranes, and DNA if left to proteins, membranes, and DNA if left to accumulate.accumulate.
CYTOSKELETONCYTOSKELETON
System of complex rods that run System of complex rods that run throughout the cytoplasm.throughout the cytoplasm.
MicrotubulesMicrotubules MicrofilamentsMicrofilaments
CENTROSOMECENTROSOME
Contains a matrix and an inner pair of Contains a matrix and an inner pair of centrioles which are important in cellular centrioles which are important in cellular division.division.
NUCLEUSNUCLEUS
Membrane bound organelle which is the Membrane bound organelle which is the control center for all cellular activity..control center for all cellular activity..
Contains DNA – produce instructions for Contains DNA – produce instructions for protein synthesis.protein synthesis.
Contain chromosomesContain chromosomes
Produce ribsomes in the nucleolusProduce ribsomes in the nucleolus
Specialized Connections Between Cells - Desmosome
1 - Microvilli
2 - Zonula occludens
3 - Zonula adherens
4 - Desmosome
5 - Terminal Web
6- Interdigitation
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 hypertrophic i.e. Muscle cells become hypertrophic in response to exercise.in response to exercise.
nucleus
Cell membrane
Rough Endoplasmic reticulum
mitochondria
Golgi apparatus
nucleolus
Nuclear membrane
Smooth Endoplasmic reticulum
OBJECTIVES for TissuesOBJECTIVES for Tissues
Be able to list the four basic tissue types Be able to list the four basic tissue types and give examples of each.and give examples of each.
Describe the functions of each tissue Describe the functions of each tissue type.type.
Describe the cellular components of each Describe the cellular components of each tissue type.tissue type.
Describe and identify the morphology of Describe and identify the morphology of epithelial tissue types.epithelial tissue types.
TissuesTissues
Cells do not operate independently.Cells do not operate independently. Related cells work and operate together Related cells work and operate together
in organized groups.in organized groups.
The bottom line:The bottom line:
Tissues are clubs of cellular organization.Tissues are clubs of cellular 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 different Occurs at the interface of two different environments.environments.
i.e. The epidermis is between the inside i.e. The epidermis is between the inside and the outside of the body.and the outside of the body.
Protects the body by detecting harmful Protects the body by detecting harmful stimuli.stimuli.
i.e. Receptors for pain are found within i.e. Receptors for pain are found within the skin.the skin.
SecretionSecretion
release of molecules from the cellrelease of molecules from the cell
AbsorptionAbsorption
bringing small molecules into the cell.bringing small molecules into the cell.
Ion transport – moves ions (charged Ion transport – moves ions (charged molecules) across a membrane.molecules) across a membrane.
The epithelium filters fluids that cross the The epithelium filters fluids that cross the barrier.barrier.
Characteristics of Characteristics of Epithelial TissueEpithelial Tissue
1. Cellularity 1. Cellularity – composed almost entirely of – composed almost entirely of cells.cells.
2. Specialized Contacts – 2. Specialized Contacts – connects adjacent connects adjacent cells.cells.
gap junctions, tight junctions, desmosomesgap junctions, tight junctions, desmosomes3. Polarity 3. Polarity – under surface called the – under surface called the
“basement membrane”.“basement membrane”.4. Avascular 4. Avascular – lacks blood vessels. Receives – lacks blood vessels. Receives
nutrients through the underlying connective nutrients through the underlying connective tissuetissue
5. 5. RegenerationRegeneration – replaces lost/dead – replaces lost/dead cells quickly.cells quickly.
Shapes of Epithelial Shapes of Epithelial TissueTissue
Simple Epithelium – one layerSimple Epithelium – one layer Stratified Epithelium – more than one Stratified Epithelium – more than one
layerlayer Squamous – cells are wider than tallSquamous – cells are wider than tall Cuboidal – cells are just about as tall as Cuboidal – cells are just about as tall as
widewide Columnar – cells are taller than wide.Columnar – cells are taller than wide.
Pseudostratified Ciliated Columnar Epithelium
Pseudostratified ciliated columnar epithelium with pale goblet cells. The different levels of nuclei are clearer here. Again, notice the wavy-looking cilia
Stratified squamous epithelium with beginning surface cornification. This section is from thin skin, which has a dry surface covered with dead cells. Notice how flat the surface cells are and how dark and pyknotic (degenerative) their nuclei have become. Again, notice the distinct row of basal cells.
CONNECTIVE TISSUECONNECTIVE TISSUE
Types of connective tissueTypes of connective tissue
FatFat
CartilageCartilage
Ligaments and TendonsLigaments and Tendons
BoneBone
BloodBlood
CollagenCollagen
Functions of Connective Functions of Connective TissueTissue
1. Support and bind other tissues. (tendons, 1. Support and bind other tissues. (tendons, ligaments)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.
A stretched preparation
of areolar connective tissue. The pink fibers of different thicknesses are collagenous (or white) fibers. The dark, thin, more tortuous fibers are elastic (or yellow) fibers. Most of the nuclei belong to fibroblasts.
Fat cells -- note nucleus and rim of cytoplasm pushed to one side by the accumulation of fat. The lipid itself has been dissolved out in fixation. In the center of the picture, in the space bounded by the four large fat cells, there is a small, round cross-cut of a capillary with a dark, shrunken red blood cell inside.
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 walls 3. smooth – no visible striations. Found in walls of hollow visceral organs such as digestive of hollow visceral organs such as digestive system, urinary organs, blood vessels, and system, urinary organs, blood vessels, and uterus. Mostly involuntary.uterus. Mostly involuntary.
Nerve TissueNerve Tissue
Uses electrical impulses to transport Uses electrical impulses to transport information.information.
Can RegenerateCan Regenerate