Effective Study Habits1.Develop a routine (time, place, no distractions, take breaks).2.Pay attention to the schedule.3.In addition to notes write down details and specific examples provided in class.4.Interact!!5.Recap daily.6.Test yourself!7.Read!

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Figure 4.1 Overview of four tissue types: epithelial, connective, muscle, and nervous tissues.

Nervous tissue: Internal communication• Brain, spinal cord, and nerves

Muscle tissue: Contracts to cause movement• Muscles attached to bones (skeletal)• Muscles of heart (cardiac)• Muscles of walls of hollow organs (smooth)

Epithelial tissue: Forms boundaries between different environments, protects, secretes, absorbs, filters• Skin surface (epidermis)• Lining of GI tract organs and other hollow organs

Connective tissue: Supports, protects, bindsother tissues together• Bones• Tendons• Fat and other soft padding tissue

Page 117

Cell Type

Epithelial 1. Squamous 2. Columnar 3. Cuboid

FunctionsA.Protection 1. Barrier against infection 2. Reduces dehydration 3. Reduces friction

a. cells sloughb. secretions (serous fluid,

mucous)B. Glandular secretionsC. Absorption

Locations? Pg 1.28

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Figure 4.2b Classification of epithelia.

Squamous (scale)

Cuboidal (glands)

Columnar(b) Classification based on cell shape. Page 119

Cells Simple Small 6-Sided (tightly

packed) Little Space *Highly MitoticAvascularNerve Endings

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Figure 3.5 Cell junctions.

Interlockingjunctionalproteins

Intercellularspace

Intercellularspace

Plasma membranesof adjacent cells

Microvilli

Intercellularspace

Basement membrane

Plaque

Linkerglycoproteins(cadherins)

Intermediatefilament(keratin)

Intercellularspace

Channelbetween cells(connexon)

(a) Tight junctions: Impermeable junctions prevent molecules from passing through the intercellular space.

(b) Desmosomes: Anchoring junctions bind adjacent cells together and help form an internal tension-reducing network of fibers.

(c) Gap junctions: Communicating junctions allow ions and small molecules to pass from one cell to the next for intercellular communication.

Pg 67Tight seal b/t cells

Areas of high friction or stress

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Figure 4.2b Classification of epithelia.

Squamous (scale)

Cuboidal glands

Columnar(b) Classification based on cell shape. Page 119

Cells Simple Small 6-Sided (tightly

packed) Little Space *Highly MitoticAvascularNerve Endings

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Figure 4.2a Classification of epithelia.

Stratified

Simple

Apical surface (free)

Basal surface

Apical surface

Basal surface

(a) Classification based on number of cell layers.

Pg 119

-Low wear & tear-Absorption & Filtration

Basement membrane

-High wear & tear

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Figure 4.3d Epithelial tissues.

Pseudostratified columnar epithelium

Function: Secrete substances, particularly mucus; propulsion of mucus by ciliary action.

Description: Single layer of cells of differing heights, some not reaching the free surface; nuclei seen at different levels; may contain mucus-secreting cells and bear cilia.

Photomicrograph: Pseudostratified ciliated columnar epithelium lining the human trachea (800x).

Cilia

Basement membrane

Pseudo-stratified epithelial layer

Location: Nonciliated type in male’s sperm-carrying ducts and ducts of large glands; ciliated variety lines the trachea, most of the upper respiratory tract.

Trachea

Pg 122

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Figure 4.3a Epithelial tissues.

(a) Simple squamous epithelium

Description: Single layer of flattenedcells with disc-shaped central nucleiand sparse cytoplasm; the simplestof the epithelia.

Function: Allows passage ofmaterials by diffusion and filtrationin sites where protection is notimportant; secretes lubricatingsubstances in serosae.

Location: Kidney glomeruli; air sacsof lungs; lining of heart, bloodvessels, and lymphatic vessels; liningof ventral body cavity (serosae).

Photomicrograph: Simple squamous epitheliumforming part of the alveolar (air sac) walls (125x).

Air sacs oflung tissue

Nuclei ofsquamousepithelialcells

Pg 120

Line cavities, cover organs, alveoli, B.V. , secretory

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Simple Squamous Apical View

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Figure 4.3c Epithelial tissues.

Function: Absorption; secretion of mucus, enzymes, and other substances; ciliated type propels mucus (or reproductive cells) by ciliary action.

Location: Nonciliated type lines most of the digestive tract (stomach to rectum), gallbladder, and excretory ducts of some glands; ciliated variety lines small bronchi, uterine tubes, and some regions of the uterus.

Description: Single layer of tall cells with round to oval nuclei; some cells bear cilia; layer may contain mucus-secreting unicellular glands (goblet cells).

Simple columnar epithelium

Basement membrane

Photomicrograph: Simple columnarepithelium of the small intestine mucosa (660x).

Mucus of goblet cell

Simple columnar epithelial cell

Microvilli

-Lines dig. and repro. Tracts-Microvilli-Absorption

Pg 121

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Figure 4.3b Epithelial tissues.

(b) Simple cuboidal epithelium

Description: Single layer ofcubelike cells with large,spherical central nuclei.

Function: Secretion andabsorption.

Location: Kidney tubules;ducts and secretory portionsof small glands; ovary surface.

Photomicrograph: Simple cuboidalepithelium in kidney tubules (430x).

Basementmembrane

Connectivetissue

Simplecuboidalepithelialcells

Pg 121

Cuboid = Glands

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Figure 4.3e Epithelial tissues.

(e) Stratified squamous epithelium

Description: Thick membranecomposed of several cell layers;basal cells are cuboidal or columnarand metabolically active; surfacecells are flattened (squamous); in thekeratinized type, the surface cells arefull of keratin and dead; basal cellsare active in mitosis and produce thecells of the more superficial layers.

Function: Protects underlyingtissues in areas subjected to abrasion.

Location: Nonkeratinized type formsthe moist linings of the esophagus,mouth, and vagina; keratinized varietyforms the epidermis of the skin, a drymembrane.

Photomicrograph: Stratified squamous epitheliumlining the esophagus (285x).

Stratifiedsquamousepithelium

Nuclei

Basementmembrane

Connectivetissue

Pg 123

High wear & tearSloughSkin (outer layer), openings & exits

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Figure 4.3d Epithelial tissues.

Pseudostratified columnar epithelium

Function: Secrete substances, particularly mucus; propulsion of mucus by ciliary action.

Description: Single layer of cells of differing heights, some not reaching the free surface; nuclei seen at different levels; may contain mucus-secreting cells and bear cilia.

Photomicrograph: Pseudostratified ciliated columnar epithelium lining the human trachea (800x).

Cilia

Basement membrane

Pseudo-stratified epithelial layer

Location: Nonciliated type in male’s sperm-carrying ducts and ducts of large glands; ciliated variety lines the trachea, most of the upper respiratory tract.

Trachea

Pg 121

-Lines most of Respiratory tract-Has Goblet Cells

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Figure 4.3f Epithelial tissues.

(f) Transitional epithelium

Description: Resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surface cells domeshaped or squamouslike, depending on degree of organ stretch.

Function: Stretches readily and permits distension of urinary organ by contained urine.Location: Lines the ureters, urinary bladder, and part of the urethra.

Photomicrograph: Transitional epithelium lining the urinary bladder, relaxed state (360X); note the bulbous, or rounded, appearance of the cells at the surface; these cells flatten and become elongated when the bladder is filled with urine.

BasementmembraneConnectivetissue

Transitionalepithelium

Pg 123

-withstand tension changes-lines bladder & ureters

90% of all cancers are associated with epithelial cells. Why?

Clicker Question: Which of the following statements regarding epithelial tissues are true?

1. Has a good blood supply.2. Food in the stomach would touch the apical surface of the epithelial tissue there.3. Simple arrangements of epithelia are associated with filtration and absorption.4. Pseudostratified epithelia consist of at least 2 layers of cells stacked on top of one another.

A. 1,2,4 B. 2,3,4 C. 1, 2, 3 D. 2,3