CHAPTER 3 CHAPTER 3 CELLS AND TISSUES CELLS AND TISSUES PART 1 – CELLS PART 2 - TISSUES.
Cells and Tissues – Part I Cell Structures
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Transcript of Cells and Tissues – Part I Cell Structures
Cells and Tissues – Part ICell Structures
Chapter 3Kelly Trainor
BIO 160
ObjectivesIdentify the three major cell regions (nucleus, cytoplasm, and
plasma membrane).Describe selective permeability, diffusion, osmosis, and the various
transport processes allowing solutes and molecules to pass through a membrane.
Cells and TissuesCarry out all chemical activities needed to sustain lifeCells are the building blocks of all living thingsTissues are groups of cells that are similar in structure and functionCells are not all the sameAll cells share general structuresAll cells have three main regions
NucleusCytoplasmPlasma membrane
Cytoplasmic Organelles
Cellular ProjectionsNot found in all cellsUsed for movement
Cilia move materials across the cell surface Located in the respiratory system to move mucus
Flagella propel the cell The only flagellated cell in the human body is sperm
Cell Diversity
Cell Diversity
Cell Physiology: Membrane TransportMembrane transport—movement of substances into and out of the
cellTwo basic methods of transport
Passive transport No energy is required
Active transport Cell must provide metabolic energy (ATP)
Solutions and TransportSolution—homogeneous mixture of two or more components
Solvent—dissolving medium; typically water in the bodySolutes—components in smaller quantities within a solution
Intracellular fluid—nucleoplasm and cytosolInterstitial fluid—fluid on the exterior of the cell
Selective PermeabilityThe plasma membrane allows some materials to pass while
excluding othersThis permeability influences movement both into and out of the cell
Passive Transport ProcessesDiffusion
Particles tend to distribute themselves evenly within a solutionMovement is from high concentration to low concentration, or
down a concentration gradient
Passive Transport ProcessesTypes of diffusion
Simple diffusion An unassisted process Solutes are lipid-soluble
materials or small enough to pass through membrane pores
Passive Transport ProcessesTypes of diffusion (continued)
Osmosis—simple diffusion of water Highly polar water molecules easily
cross the plasma membrane
Passive Transport ProcessesFacilitated diffusion
Substances require a protein carrier for passive transport
Transports lipid-insoluble and large substances
Active Transport ProcessesSubstances are transported that are unable to pass by diffusion
Substances may be too largeSubstances may not be able to dissolve in the fat core of the
membraneSubstances may have to move against a concentration gradient
ATP is used for transport
Active Transport ProcessesTwo common forms of active transport
Active transport (solute pumping)Vesicular transport
Exocytosis Endocytosis
PhagocytosisPinocytosis
Active Transport ProcessesActive transport (solute pumping)
Amino acids, some sugars, and ions are transported by protein carriers called solute pumps
ATP energizes protein carriersIn most cases, substances are moved against concentration
gradients
Active Transport ProcessesVesicular transport
Exocytosis Moves materials out of the cell Material is carried in a membranous vesicle Vesicle migrates to plasma membrane Vesicle combines with plasma membrane Material is emptied to the outside
Active Transport ProcessesVesicular transport (continued)
Endocytosis Extracellular substances are engulfed by being enclosed in a
membranous vescicleTypes of endocytosis
Phagocytosis—“cell eating” Pinocytosis—“cell drinking”
Cells and Tissues – Part IITissue Types
Chapter 3Kelly Trainor
BIO 160
ObjectivesName the four major tissue types, their chief subcategories and
explain how they differ structurally and functionally.Give the chief locations of the various tissue types in the body.
Body TissuesTissues
Groups of cells with similar structure and functionFour primary types
Epithelial tissue (epithelium) Connective tissue Muscle tissue Nervous tissue
Epithelial TissuesLocations
Body coveringsBody liningsGlandular tissue
FunctionsProtectionAbsorptionFiltrationSecretion
Epithelium CharacteristicsCells fit closely together and
often form sheetsThe apical surface is the free
surface of the tissueThe lower surface of the
epithelium rests on a basement membrane
Avascular (no blood supply)Regenerate easily if well
nourished
Classification of EpitheliaNumber of cell layers
Simple—one layerStratified—more than one layer
Classification of EpitheliaShape of cells
Squamous flattened
Cuboidal cube-shaped
Columnar column-like
Figure 3.17b
Simple EpitheliaSimple squamous
Single layer of flat cellsUsually forms membranes
Lines body cavities Lines lungs and capillaries
Simple EpitheliaSimple cuboidal
Single layer of cube-like cellsCommon in glands and their ductsForms walls of kidney tubulesCovers the ovaries
Simple EpitheliaSimple columnar
Single layer of tall cellsOften includes mucus-producing goblet cellsLines digestive tract
Simple EpitheliaPseudostratified columnar
Single layer, but some cells are shorter than othersOften looks like a double layer of cellsSometimes ciliated, such as in the respiratory tractMay function in absorption or secretion
Stratified EpitheliaStratified squamous
Cells at the apical surface are flattenedFound as a protective covering where friction is commonLocations
Skin Mouth Esophagus
Stratified EpitheliaStratified cuboidal—two layers of cuboidal cellsStratified columnar—surface cells are columnar, cells underneath
vary in size and shapeStratified cuboidal and columnar
Rare in human bodyFound mainly in ducts of large glands
Stratified EpitheliaTransitional epithelium
Shape of cells depends upon the amount of stretchingLines organs of the urinary system
Glandular EpitheliumGland
One or more cells responsible for secreting a particular productTwo major gland types
Endocrine gland Ductless since secretions diffuse into blood vessels All secretions are hormones
Exocrine gland Secretions empty through ducts to the epithelial surface Include sweat and oil glands
Connective TissueFound everywhere in the bodyIncludes the most abundant and widely distributed tissuesFunctions
Binds body tissues togetherSupports the bodyProvides protection
Connective Tissue CharacteristicsVariations in blood supply
Some tissue types are well vascularizedSome have a poor blood supply or are avascular
Extracellular matrixNon-living material that surrounds living cells
Extracellular MatrixTwo main elements
Ground substance—mostly water along with adhesion proteins and polysaccharide molecules
Fibers Produced by the cells Three types
Collagen (white) fibersElastic (yellow) fibersReticular fibers
Connective Tissue TypesBone (osseous tissue)
Composed of Bone cells in lacunae (cavities) Hard matrix of calcium salts Large numbers of collagen fibers
Used to protect and support the body
Connective Tissue TypesHyaline cartilage
Most common type of cartilage
Composed of Abundant collagen fibers Rubbery matrix
Locations Larynx Entire fetal skeleton prior to
birth
Connective Tissue TypesElastic cartilage
Provides elasticityLocation
Supports the external earFibrocartilage
Highly compressibleLocation
Forms cushion-like discs between vertebrae
Connective Tissue TypesDense connective tissue (dense
fibrous tissue)Main matrix element is collagen
fiberFibroblasts are cells that make
fibersLocations
Tendons—attach skeletal muscle to bone
Ligaments—attach bone to bone at joints
Dermis—lower layers of the skin
Connective Tissue TypesLoose connective tissue types
Areolar tissue Most widely distributed
connective tissue Soft, pliable tissue like
“cobwebs” Functions as a packing tissue Contains all fiber types Can soak up excess fluid
(causes edema)
Connective Tissue TypesLoose connective tissue types
Adipose tissue Matrix is an areolar tissue in
which fat globules predominate
Many cells contain large lipid deposits
Functions Insulates the bodyProtects some organsServes as a site of fuel
storage
Connective Tissue TypesLoose connective tissue types
Reticular connective tissue Delicate network of
interwoven fibers Forms stroma (internal
supporting network) of lymphoid organsLymph nodesSpleenBone marrow
Connective Tissue TypesBlood (vascular tissue)
Blood cells surrounded by fluid matrix called blood plasmaFibers are visible during clottingFunctions as the transport vehicle for materials
Muscle TissueFunction is to produce movementThree types
Skeletal muscleCardiac muscleSmooth muscle
Muscle Tissue TypesSkeletal muscle
Under voluntary controlContracts to pull on bones or
skinProduces gross body
movements or facial expressions
Characteristics of skeletal muscle cells Striated Multinucleate (more than
one nucleus) Long, cylindrical
Muscle Tissue TypesCardiac muscle
Under involuntary controlFound only in the heartFunction is to pump bloodCharacteristics of cardiac
muscle cells Cells are attached to other
cardiac muscle cells at intercalated disks
Striated One nucleus per cell
Muscle Tissue TypesSmooth muscle
Under involuntary muscleFound in walls of hollow organs
such as stomach, uterus, and blood vessels
Characteristics of smooth muscle cells No visible striations One nucleus per cell Spindle-shaped cells
Nervous TissueComposed of neurons and nerve support cellsFunction is to send impulses to other areas of the body
IrritabilityConductivity