Skin (Integument) Figure 5.3 Epidermis

Layers of the Epidermis: STRATA = LAYERS Epidermis CGSBDCGSBD CGSBDCGSBD

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 alveolus Simple squamous of alveolus Simple 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 Bladder Simple columnar epithelium lines the gall bladder. Note the underlying connective tissue with blood vessels. Bar = 100 Microns Gall Bladder Simple columnar epithelium lines the gall bladder. Note the underlying connective tissue with blood vessels. Bar = 100 Microns.

Goblet cell

... with microvilli (brush border)

cilia

... with 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 with cilia and goblet cells

Trachea Pseudostratified columnar epithelium