Apical Modifications in Epithelial Cells

Questions and Answers

What is the main function of hemidesmosomes?

Attach epithelial cells to the basement membrane (correct)

Transport substances between cells

Attach cells to each other

Provide a watertight seal between cells

Tight junctions allow for the transport of ions and water between cells.

False

What type of modification is responsible for providing cementing to keep neighboring cells together?

Adherens junction

The __________ are channels that allow for the transport of ions, water, and other substances between neighboring cells.

gap junctions Signup and view all the answers

Match the following types of cell junctions with their function:

Tight Junctions = Create a watertight seal between cells Gap Junctions = Allow for communication between cells Hemidesmosomes = Attach epithelial cells to the basement membrane Adherens Junctions = Provide cementing to keep neighboring cells together Signup and view all the answers

What is the primary function of cilia on epithelial cells?

Movement of material over the epithelial surface Signup and view all the answers

Flagella are short, hairlike structures that assist in the movement of material over epithelial surfaces.

False Signup and view all the answers

What are villi and why are they important for absorption?

Villi are finger-like projections that increase surface area for faster and more efficient absorption. Signup and view all the answers

________ are temporary, irregular lobes formed by certain eukaryotic cells for motility and ingestion.

Pseudopods Signup and view all the answers

Match the following structures with their primary functions:

Cilia = Movement of material Flagella = Locomotion Villi = Increasing surface area for absorption Pseudopods = Motility and ingestion Signup and view all the answers

Which component is primarily responsible for the structure of plant cell walls?

Cellulose Signup and view all the answers

Microvilli are generally larger than villi and serve the same function.

False Signup and view all the answers

What are actin filaments primarily associated with in terms of cell structure?

Motility and the formation of pseudopods. Signup and view all the answers

Study Notes

Apical Modification

Cilia: Short, hairlike projections found on the apical surface of epithelial cells, aiding in the movement of materials parallel to the epithelial surface, prominent in tracheal epithelial tissue.
Flagella: Long, whip-like structures composed of microtubules found in bacteria and some eukaryotic cells, primarily responsible for locomotion; an example includes sperm cells.
Villi and Microvilli:
- Villi: Finger-like projections that increase surface area for efficient absorption in certain organs.
- Microvilli: Smaller projections than villi, primarily enhance absorption efficiency of molecules, notably seen in the duodenum's columnar epithelium.
Pseudopods: Temporary, irregular lobes formed by amoebas for movement and engulfing prey, consist mainly of actin filaments, occasionally containing microtubules and intermediate filaments.
Extracellular Matrix (ECM): Secreted by cells, facilitating communication and attachment between nearby cells, crucial for cell functions like growth and movement. In plant cells, the cell wall made of cellulose distinguishes them from animal cells, forming fibers known as microfibrils.

Basal Modification

Hemidesmosomes: Structures that anchor epithelial cells to the basement membrane, contributing to epithelial integrity and stability.

Lateral Modification

Tight Junctions: Create a watertight seal between adjacent cells to prevent liquid leakage; vital in preventing urine from escaping the epithelial layer lining the bladder.
Gap Junctions: Channels that enable the passage of ions, water, and other substances between neighboring cells, facilitating intercellular communication.
Adherens/Adhering Junctions: Act as "cement" to hold neighboring cells together, reinforcing tissue structure and cohesion.

Description

This quiz explores the various apical modifications found in epithelial cells, focusing on structures such as cilia and flagella. Understand the function and significance of these organelles in aiding movement across epithelial surfaces, particularly in tissues like the trachea. Test your knowledge on these crucial cellular features.