Epithelial Tissue Quiz

What is epithelial tissue? | Tissue that covers and lines surfaces and performs secretion and absorption.

What are the 4 main functions of epithelial tissue? | Physical barrier, regulates exchange, produces secretions, provides sensation.

Physical barrier | Protects exposed internal and external surfaces.

Regulates exchange | Controls substances entering or leaving the body.

Produces secretions | Glandular epithelium releases substances such as mucus, sweat, and oil.

Provides sensations | Detects touch, temperature, pain, and pressure.

What special senses involve epithelium? | Vision, taste, smell, hearing, and balance.

What are the 5 characteristics of epithelial tissue? | Cellularity, polarity, attachments, avascularity, high regeneration.

Cellularity | Mostly cells with very little extracellular material.

Polarity | Epithelium has an apical side and a basal side.

Apical surface | Exposed/free surface of epithelial tissue.

Basal surface | Bottom surface attached to the basement membrane.

Attachments | Connections between epithelial cells and the basement membrane.

Avascularity | Epithelial tissue has no blood vessels.

How does epithelium get oxygen and nutrients? | From nearby connective and other tissues.

Highly regenerative | Epithelium constantly makes new cells to replace lost cells.

Why must epithelial tissue regenerate often? | Exposed cells are constantly being lost or shed.

Which epithelial cells actively divide? | Basal cells.

Progenitor cells | Cells that divide to produce new epithelial cells.

What is a callus? | Thickened skin caused by repeated stress.

What is the basement membrane? | Thin structure connecting epithelium to deeper connective tissue.

What are the 2 layers of the basement membrane? | Basal lamina and reticular lamina.

Basal lamina | Basement membrane layer made by epithelial tissue.

Reticular lamina | Basement membrane layer made by connective tissue.

What are the 2 parts of the basal lamina? | Lamina lucida and lamina densa.

Lamina lucida | Clear layer closer to the epithelium.

Lamina densa | Dense layer closer to connective tissue.

What are the 4 epithelial cell attachments? | Tight junctions, desmosomes, hemidesmosomes, gap junctions.

Tight junction | Seal between neighboring cells that blocks unwanted substances.

What is a tight junction like? | A zip-lock seal around the top of cells.

Where are tight junctions located? | Near the apical end.

What can tight junctions help block? | Bacteria, fungi, and other unwanted substances.

Desmosome | Attachment between neighboring cells that provides mechanical support.

What is a desmosome like? | A spot-weld between cells.

Where are desmosomes located? | Near the basal end.

What do desmosomes help with? | Keep cells attached when tissue stretches.

Hemidesmosome | Anchors basal epithelial cells to the basement membrane.

Gap junction | Protein channel connecting neighboring cells.

What do gap junctions allow? | Cell-to-cell communication.

What can travel through gap junctions? | Ions and other substances.

Cilia | Hair-like structures that move substances across a cell surface.

What is an example of something cilia move? | Mucus.

Microvilli | Membrane extensions that increase surface area.

What is the main function of microvilli? | Increase absorption.

Where are cilia and microvilli found? | On the apical surface.

What 2 things classify epithelial tissue? | Number of layers + shape of apical cells.

Simple epithelium | One layer of cells.

Stratified epithelium | More than one layer of cells.

Which cells determine the name of epithelial tissue? | The apical/exposed cells.

Squamous cells | Flat, squashed-looking cells.

What does a squamous nucleus look like? | Flat and centrally located.

Cuboidal cells | Cube-shaped cells.

What does a cuboidal nucleus look like? | Round and centrally located.

Columnar cells | Tall, column-shaped cells.

What special structures can columnar cells have? | Cilia and microvilli.

Transitional cells | Cells that change shape as tissue stretches.

What is pseudostratified? | Looks stratified but is actually one layer.

Why does pseudostratified tissue look multilayered? | Its nuclei appear at different heights.

Do all pseudostratified cells touch the basement membrane? | Yes.

How many basic epithelial tissue classifications are in the notes? | 8.

What are the 4 simple epithelial tissues? | Simple squamous, simple cuboidal, simple columnar, pseudostratified ciliated columnar.

What are the 4 stratified epithelial tissues? | Stratified squamous, stratified cuboidal, stratified columnar, transitional.

Simple squamous epithelium | One layer of flat cells.

Simple squamous location | Glomerular capsule of the kidney.

Simple squamous is good for what? | Fast exchange across a thin surface.