Skin (Integument) Figure 5.3 Epidermis Layers of the Epidermis: STRATA = LAYERS Epidermis CGSBDCGSBD CGSBDCGSBD.

Skin (Integument)

Figure 5.3Epidermis

Layers of the Epidermis: STRATA = LAYERS

Epidermis

C

G

S

B

D

C

G

S

B

D

Tissues

• Groups of cells similar in structure and function

• The four types of tissues–Epithelial

–Connective

–Muscle

–Nerve

EPITHELIAL TISSUE

Epithelial Tissue

–covers the body surfaces

–lines the lumen of organs

–lines the body cavities

–forms glands and lines ducts

Epithelial Tissue - characteristics• Cellularity –• Special contacts – tight / desmosomes• Polarity – apical / basal• Supported by connective tissue – lamina• Avascular but innervated – • Regenerative –

Classification of Epithelia

• Simple or stratified

Figure 4.1a

apical

basal

Classification of Epithelia• Squamous, cuboidal,

or columnar

• DESCRIPTION

Figure 4.1b

Simple Squamous

Figure 4.2a

DESCRIPTION

FUNCTIONS

PRESENCE- glomeruli, alveoli, etc.

Alv Org

Lung XS

Alv Org

AL

Type II cell

C

Squamous

(bar = 1um)

Lumen of alveolusSimple squamous of alveolusSimple squamous of capillary

Lumen of alveolus

Respiratory membrane

Capillary Simple squamous epithelium

Capillary wall is Simple squamous epithelium

Kidney (Glomerulus) Simple squamous epithelium (arrow) lines the glomerulus. Bar = 50um

NEPHRON TUBULE CONTAINS THE GLOMERULUS

Epithelia: Simple Cuboidal

Figure 4.2b

• DESCRIPTION• FUNCTIONS• PRESENCE-

Beginning of nephron tubule

Longitudinal section of nephron tubules

Cross section of nephron tubules

2,000L 180L

1.5L

FILTER RESORB SECRETE

EXCRETE

Epithelia: Simple Columnar

Figure 4.2c

DESCRIPTION

FUNCTIONS

PRESENCE

Gall BladderSimple columnar epithelium lines the gall bladder. Note the underlying connective tissue with blood vessels.

Bar = 100 Microns

Gall BladderSimple columnar epithelium lines the gall bladder. Note the underlying connective tissue with blood vessels.

Bar = 100 Microns.

Goblet cell

... ... with microvilli (brush border)with microvilli (brush border)

ciliacilia

... ... with ciliawith cilia

Figure 4.2d

DESCRIPTION

FUNCTIONS

PRESENCE

Trachea The pseudostratified columnar epithelium of the trachea is ciliated and has goblet cells.

Bar = 50 um

Pseudostratified columnar epithelium Pseudostratified columnar epithelium with cilia and goblet cellswith cilia and goblet cells

Trachea Pseudostratified columnar epithelium