1A03 - TISSUES

Characteristics of Epithelia

Characteristics of Epithelia

• densely packed

• little matrix

• distinctive cell surfaces

Surfaces of Epithelia

apical, basal, lateral

Basement Membranes of Epithelia

• extracellular

• porous

• avascular

• regenerated

• attaches epithelia to CT

• acts as glue

Functions of Epithelia

• protection

• secretion

• absorption

• filtration

• diffusion

Epithelial Cell Surface Modifications

microvilli: increased surface area for absorption or secretion

cilia: move materials across cell surface

Functions of Simple Epithelial Cells

• diffusion

• blood filtration

• secretion

• absorption

Functions of Stratified Epithelial Cells

• protection

Functions of Pseudostratified Epithelial Cells

• secretion

• mucus movement

Functions of Squamous Epithelial Cells

• diffusion

• filtration

Functions of Cuboidal/Columnar Epithelial Cells

• secretion

• absorption

• may include goblet cells

Goblet Cells

produce and secrete mucus

Glands

• epithelium with supporting network of CT

• endocrine and exocrine

Simple Squamous Epithelia

• diffusion

• filtration

• secretion

• endothelium

• serous membranes

• alveoli

• bowman's capsule

Simple Cuboidal Epithelia

• secretion

• absorption

• kidney tubules

• glands+ducts

• ovary surface

Simple Columnar Epithelia

• movement

• secretion

• absorption

• glands

• bronchioles

• uterus + uterine tubes

• stomach

• intestines

• gallbladder

• ventricles of brain

Psudostratified Columnar Epithelia

• synthesize+secrete+move mucus

• absorption

• protection

• lining of most of upper respiratory tract (ciliated)

• male urethra and epidymis (non-ciliated)

Stratified Squamous Epithelia

• protection

keratinized: skin non-keratinized: mouth, throat, esophagus, anus, vagina

Transitional Epithelia

• regulation (fluid volume)

• protection (against urine)

• lining of urinary system

Connective Tissue Characteristics

• abundant

• consists of cells separated by extracellular matrix

• mostly vascular

• supports extracellular matrix

Connective Tissue Functions

• encloses organs as a capsule

• connects tissues

• storage

• insulation

• transportation

• protection

Extracellular Matrix

protein fibres + ground substance

Extracellular Matrix - Protein fibres

collagen: strong, flexible, inelastic

reticular: fill space, fine collagenous, form branching networks

elastic: made from elastin, crosss linked

Elastin

protein surrounded by fibrillin (a glycoprotein)

Extracellular Matrix - Ground Substance

hyaluronic acid: reduces friction

proteoglycan: long protein core with many polysaccharides

adhesion proteins: fill in space, attach fibres (to cell walls and each other)

Loose CT

areolar: mostly collagen; fills in space

adipose: from adipose cells; store fat

reticular: from reticular fibres; form structures in lymphatic system

Dense CT

regular: fibres line up irregular: fibres in many directions