Cell Modification Flashcards
As basic units of life, cells have some forms of adaptations that are manifested as what?
Cell modifications
Some cell modifications that are only present on the __ ___ of epithelial cells
apical surface
Apical Cell modification
Microvilli, Cilia, stereocilia, flagella
Are extensions of the cell membrane that appear as hair-like apical protrusions. Have excellent absorptive properties. Usually present in epithelial tissues that function for absorption, such as those in the intestines
Microvilli
Are hair-like projections in the apical surface of columnar epithelial cells. Longer than microvilli. For the sweeping of mucus and dirt from the respiratory tract. In the fallopian tubes, these are important in the movement of egg cells from the ovary to the respiratory tract
Cilia
Two types of cilia
Nonmotile cilia, Motile cilia
Most commonly found on mammalian cells. Are essential in signaling and in detecting stimuli
Nonmotile cilia
Are usually present in groups and move in a coordinated manner. Important in the movement of substances
Motile cilia
are similar to microvilli and cilia but are longer nonmotile. Found on the epididymis’ epithelial cells. Help absorb and secrete molecules by increasing the cell’s surface area. Also present in the inner ear.
Stereocilia
Hair cells in the ____ have stereocilia that are important in the reception of sound and its transformation into electrical signal. In this case, stereocilia have a sensory function
Cochlea
Are much longer than cilia and usually occur only in singles on every cell surface. Move in a wavelike motion. Most common example is a sperm cell. Some species of bacteria and protists also possess one or two of this
Flagella
Are present along the lateral and basal surfaces of the cells.
Lateral and Basal cell modifications
Multi-protein complexes that serve as connections between cell or as connections between cell or as connection between cells and their extracellular matrix
Cellular junctions
Types of Cellular Junctions
Tight Junction, Gap Junction, Adherens Junction, Desmosomes
Also known as occluding junctions. Found in the lateral sides of cells. They prevent the leakage of water, solute molecules, or ions. Lining of the intestinal walls and kidney contain these
Tight junction
Are tunnel-like intercellular junctions that connect the cytoplasm of two adjacent cells. Allow the cells to exchange signaling molecules easily. Allow cell to communicate. Commonly found in neurons
Gap junctions
Connect the cytoskeleton of two adjacent cells. Maintaining cell-to-cell adhesion and structural integrity. During embryonic development, these junctions are assembled and re-assembled to transform into more advanced cell types
Adherens Junction
Connect the cytoskeleton of two adjacent cells. They are tough cell junctions and are present in tissues that experience mechanical stress, like cardiac muscle tissues
Desmosomes
Similar to desmosomes. But unlike desmosomes, they adhere cells to the extracellular matrix. These junctions are present in the upper respiratory tract as well as the intestines
Hemidesmosomes
Are finger-like extensions of the cell membrane and cytoplasm. They are neither apical nor basal modifications. These structures appear as arm-like projections that function for ingestion and movement. Are common in protozoan cells like amoebas
Pseudopods
