Animal Tissues & Cell Modifications Study
Guide
Transcribed and Formatted Notes
1. Cell Modifications
Apical Modifications
Cilia and Flagella:
Cilia: Are usually short, hair-like structures that move in waves. Type of cell modification that
sweeps the mucus.
Flagella: Are long whip-like structures formed from microtubules.
Villi and Microvilli:
These are finger-like projections that arise from the epithelial layer in some organs.
They help to increase surface area for faster and more efficient absorption.
Extra-Cellular Matrix (ECM):
It is a compound (glycoprotein) secreted by the cell on its apical surface.
Cell wall is the extra-cellular structure in plant cells that distinguishes them from animal cells.
Lateral Modifications
A type of cell modification that is found on the lateral surface of the cell. Happens at the side of the cell.
Gap Junction: It is also known as communicating junctions. Closable channels that connect the
cytoplasm of adjoining animal cells.
Tight Junction: It acts as barriers that regulate the movement of water and solutes between
epithelial layers. It prevents leakage of ECF (extracellular fluid).
Adhering Junction: It anchors junction on the lateral surface of the cell. It is similar to the anchoring
junction of the basal surface of the cell.
Desmosomes: Anchoring junctions bind adjacent cells together like a molecular 'Velcro' and help
form an internal tension-reducing network of fibers.
Basal Modifications
A type of modification that is found on the basal surface of the cell. Occurs at the bottom part of the
cell.
Examples: Basal folding and hemidesmosomes.
Desmosomes / Hemidesmosomes: The anchoring junction on the basal surface of the cell.
Hemidesmosomes: Rivet-like links between cytoskeleton and extracellular matrix components
such as the basal lamina that underlie epithelia.
Guide
Transcribed and Formatted Notes
1. Cell Modifications
Apical Modifications
Cilia and Flagella:
Cilia: Are usually short, hair-like structures that move in waves. Type of cell modification that
sweeps the mucus.
Flagella: Are long whip-like structures formed from microtubules.
Villi and Microvilli:
These are finger-like projections that arise from the epithelial layer in some organs.
They help to increase surface area for faster and more efficient absorption.
Extra-Cellular Matrix (ECM):
It is a compound (glycoprotein) secreted by the cell on its apical surface.
Cell wall is the extra-cellular structure in plant cells that distinguishes them from animal cells.
Lateral Modifications
A type of cell modification that is found on the lateral surface of the cell. Happens at the side of the cell.
Gap Junction: It is also known as communicating junctions. Closable channels that connect the
cytoplasm of adjoining animal cells.
Tight Junction: It acts as barriers that regulate the movement of water and solutes between
epithelial layers. It prevents leakage of ECF (extracellular fluid).
Adhering Junction: It anchors junction on the lateral surface of the cell. It is similar to the anchoring
junction of the basal surface of the cell.
Desmosomes: Anchoring junctions bind adjacent cells together like a molecular 'Velcro' and help
form an internal tension-reducing network of fibers.
Basal Modifications
A type of modification that is found on the basal surface of the cell. Occurs at the bottom part of the
cell.
Examples: Basal folding and hemidesmosomes.
Desmosomes / Hemidesmosomes: The anchoring junction on the basal surface of the cell.
Hemidesmosomes: Rivet-like links between cytoskeleton and extracellular matrix components
such as the basal lamina that underlie epithelia.
