Chapter 3a

Compartmentation: Cells and Tissues

About this Chapter

• Body compartments• Biological membranes• Intracellular compartments• Tissue types and characteristics• Tissue remodeling• Organs

Three Major Body Cavities

Figure 3-1

PleuralsacPericardialsac

Diaphragm

Pelviccavity

Abdominalcavity

Abdominopelviccavity

POSTERIOR ANTERIOR

Cranial cavity

Thoraciccavity

Body Cavities

Lumens of Hollow Organs

• Hollow organs• Heart• Lungs• Blood vessels• Intestines

• Lumen• Not the internal environment

Functional Compartments

1. Outside Body2. Extracellular fluid• Plasma• Interstitial fluid

3. Intracellular fluid4. Organelles and vacuoles

Body Fluid Compartments

Figure 3-2

ICFECF

Plasma Interstitial fluid Intracellular fluid

Blood vessel

Cellmembrane

Cell membrane

Bloodcells

Capillary wall

Cell Membrane: Overview

• Membranes in the body

Figure 3-3

Cell

Loose connectivetissue

Seen magnified, the pericardial membrane is a layer of flattened epithelial cells supported by connective tissue.

The pericardial membrane is a tissue that surrounds the heart.

Each cell of thepericardial membranehas a cell membranesurrounding it.

The cell membraneis a phospholipidbilayer.

Pericardialmembrane

Heart

Cell Membrane: Functions

• Physical barrier• Gateway for exchange• Communication• Cell structure

Cell Membrane: Structure

• The fluid mosaic model of a biological membrane

Figure 3-4

Cholesterolmolecules insertthemselves into

the lipid layer.

Carbohydrate groupof glycoprotein

Carbohydrate groupof glycolipid

Extracellular surfaceof membrane

Phospholipid heads face the aqueous intracellular and extracellular compartments.

Lipid tails form the interiorlayer of the membrane.

Intracellularsurface ofmembrane

Membranesplits into layersin freeze-fractureelectronmicroscopy.

Proteins

• Proteins• Integral • Peripheral• Lipid-anchored

Cell Membrane: Composition

• Lipids • Phospholipids• Sphingolipids• Cholesterol

Cell Membrane: Composition

Table 3-1

Cell Membrane: Structure and Formation

• Phospholipids have polar and non-polar regions

Figure 3-5a

Phospholipid molecules have polar heads and nonpolar tails.The “R” group is a variable polar group.

Nonpolarfatty acid

tail(hydrophobic)

Polar head(hydrophilic)

Stylized modelMolecular modelsStructural model

(a)

Figure 3-5b

Cell Membrane: Formation

• Membrane phospholipids form bilayers, micelles, or liposomes

Phospholipids arrange themselves so that their nonpolar tails are not in contact with aqueous

solutions such as extracellular fluid.

Phospholipid bilayerforms a sheet.

Micelles are dropletsof phospholipids.

Liposomes havean aqueous center.

Tails

(b)

Cell Membrane: Proteins

• The three types of membrane proteins: integral, peripheral, and lipid-anchored

Figure 3-6

Peripheral protein

Glycoprotein

Peripheralprotein

Integral(transmembrane)

protein

Cytoskeletonproteins

Lipid-anchoredproteins

Cytoplasm

Cell Membrane: Lipid Rafts

• Sphingolipids and alkaline phosphatase

Figure 3-8

Cell Membrane Components

Figure 3-9

Cholesterol ProteinsPhospholipids, Sphingolipids Carbohydrates

GlycoproteinsLipid bilayer Glycolipids

Cellrecognition

Immuneresponse

Structuralstability

CELL MEMBRANE

consists of

together form

functions as

together form together form

whose functions include

Selective barrierbetween cytosol andexternal environment

Intracellular Compartments

• Cytoplasm• Cytosol• Inclusions• Organelles

• Nucleus

Cell Compartments

• A map for the study of cell structure

Figure 3-11

Cytoplasm

Cytosol

Nucleus

Cellmembrane

THE CELL

is composed of

• Lipid droplets• Glycogen granules• Ribosomes• Vaults• Proteasomes• Cytoskeleton• Centrioles• Centrosomes• Cilia• Flagella

Inclusions

• Mitochondria• Endoplasmic reticulum• Golgi complex• Lysosomes• Peroxisomes

Membranousorganelles

Extracellular fluid

Inclusions Have No Membranes

• Ribosomes• Free• Fixed• Polyribosomes

• Proteasomes• Vaults• RNA/protein

Cytoplasmic Proteins Fibers

• Actin (microfilaments)• Intermediate• Myosin• Keratin• Neurofilaments

• Microtubules• Tubulin• Centrioles, cilia, flagella

Microtubule function

• Centrioles• Pull chromosomes• Form core in cilia

• Cilia and flagella• Fluid movement

Centrioles

Figure 3-13a–b

Cilia and Flagella

Figure 3-13c–d

Cytoskeleton: Function

• Cell shape • Internal organization• Intracellular transport• Assembly of cells into tissues• Movement

Cytoskeleton and Cytoplasmic Protein Fibers

Figure 3-14(b)

Microvilli increase cell surface area.

They are supportedby microfilaments.

Microfilaments forma network just insidethe cell membrane.

Microtubulesare the largest

cytoskeleton fiber.

Intermediatefilaments include

myosin and keratin.

(a)

Figure 3-15

Cytoskeleton and Cytoplasmic Protein Fibers

• Motor proteins move on cytoskeletal fibers

Cytoskeletal fiber

Organelle

Motorprotein

Direction ofmovement

ATP

Mitochondria

• Membrane-enclosed compartments• Unique DNA• Site of cellular ATP generation

Mitochondria

Figure 3-16

Matrix is theinnermost

compartment.

Cytosolic sideof membrane

Outermembrane

Inner membraneCytoplasm

of cellMatrix

Cristae

The intermembranespace forms a compartment.

Endoplasmic Reticulum (ER)

• Smooth ER• Synthesis of fatty acids, steroids, lipids• Modified forms in liver, kidney, muscles

• Rough ER• Rows of ribosomes• Protein assembly and modification

Endoplasmic Reticulum

Figure 3-17

Ribosomes are attachedto cytosolic side of rough

endoplasmic reticulum.

Lumen ofendoplasmicreticulum

Endoplasmicreticulum

Smooth endoplasmic reticulum