30 Questions
Which type of junctions anchor actin filaments in a cell to the extracellular matrix?
Integrins
What do integrins bridge in cell-cell interactions?
Cell membranes
Which proteins activate integrins after binding?
Intracellular activator proteins
What can be influenced by the intracellular signals produced by activated integrins?
All of the above
What do hemidesmosomes facilitate?
Stable adhesion of epithelial cells to the basement membrane
Which type of junctions anchor intermediate filaments in a cell to the extracellular matrix?
Hemidesmosomes
Which type of junctions anchor actin filaments in a cell to the extracellular matrix?
Integrins
What are the main functions of integrins?
All of the above
What do integrins depend on for their function?
Extracellular matrix
Which proteins are similar in form to desmosomes but use integrins instead of desmogleins?
Hemidesmosomes
Which type of tissue is characterized by tightly bound cells that are anchored onto the basal lamina through cell-matrix junctions?
Epithelial tissue
Which of the following is NOT a function of cell junctions?
Build up the paracellular barrier of epithelia
What is the main function of cell-cell junctions in epithelial tissues?
Bond cells together
What is the purpose of cell-matrix junctions?
Anchor cells onto the basal lamina
Which of the following is NOT a type of cell-cell junction?
Hemidesmosome
Which of the following is NOT a relevant tissue type where cell junctions are particularly abundant?
Connective tissues
What is the purpose of the junctional complex?
Bond cells together
Which of the following is NOT a component of the junctional complex?
Gap junctions
Which of the following cell types are packed into tight communities in the body?
Epithelial cells
What is the purpose of the paracellular barrier of epithelia?
Control paracellular transport
Which type of cell junction forms strong structural connections between cells and is often found in cardiac muscle and fibroblasts?
Desmosomes
Which type of cell junction seals the gap between epithelial cells and serves as a selective permeability barrier for paracellular transport?
Tight junctions
Which type of cell junction allows the passage of small water-soluble molecules from cell to cell, without having to pass through the plasma membrane?
Gap junctions
Which type of cell junction forms strong, membrane-spanning structures that are tethered inside the cell to the tension-bearing filaments of the cytoskeleton?
Adherens junctions
Which type of cell junction is formed by transmembrane adhesion proteins that belong to the cadherin family?
Adherens junctions
Which type of cell junction is widely distributed in animal tissues and most abundant in tissues that are subjected to severe mechanical stress?
Adherens junctions
Which type of cell junction is rare and has direct attachments between cells?
Tight junctions
Which type of cell junction is important in tissue remodeling and is located more basal than tight junctions?
Adherens junctions
Which type of cell junction provides anchorage sites for the cytoskeleton and helps in modeling the shape of multicellular structures?
Adherens junctions
Which type of cell junction is structurally similar to adherens junctions but contains specialized proteins that link with intermediate filaments instead of actin?
Desmosomes
Study Notes
Cell Junctions
Anchoring Filaments
- Focal adhesions anchor actin filaments in a cell to the extracellular matrix
- Hemidesmosomes anchor intermediate filaments in a cell to the extracellular matrix
Integrins
- Integrins bridge the extracellular matrix and the cytoskeleton in cell-matrix interactions
- Integrins are activated by proteins called talin and kindlin after binding to the extracellular matrix
- Activated integrins can influence various cellular processes, such as proliferation, migration, and differentiation
- Integrins depend on the presence of divalent cations, such as calcium and magnesium, for their function
Cell-Cell Junctions
- Desmosomes bridge cells in cell-cell interactions
- Integrins can also bridge cells in cell-cell interactions
- Intercellular adhesion molecules (ICAMs) are involved in cell-cell interactions
Tissue Characteristics
- Epithelial tissue is characterized by tightly bound cells that are anchored onto the basal lamina through cell-matrix junctions
- Cardiac muscle tissue often contains desmosomes and gap junctions
- Fibroblasts contain focal adhesions and adherens junctions
Cell Junction Functions
- The main function of cell-cell junctions in epithelial tissues is to provide mechanical strength and cohesion
- The main function of cell-matrix junctions is to provide anchorage and traction forces
- The purpose of the junctional complex is to provide a strong structural connection between cells and the extracellular matrix
- The paracellular barrier of epithelia provides a selective permeability barrier for paracellular transport
Cell Junction Types
- Tight junctions seal the gap between epithelial cells and serve as a selective permeability barrier for paracellular transport
- Gap junctions allow the passage of small water-soluble molecules from cell to cell, without having to pass through the plasma membrane
- Adherens junctions form strong structural connections between cells and are often found in cardiac muscle and fibroblasts
- Focal adhesions form strong, membrane-spanning structures that are tethered inside the cell to the tension-bearing filaments of the cytoskeleton
- Hemidesmosomes provide anchorage sites for the cytoskeleton and help in modeling the shape of multicellular structures
- Desmosomes are structurally similar to adherens junctions but contain specialized proteins that link with intermediate filaments instead of actin
- Macula adherens are rare and have direct attachments between cells
Test your knowledge of cell-cell junctions with this quiz! Learn about the different types of junctions found along the lateral and basal surfaces of cells, their structure, functions, and relevance to cells and tissues. Explore the components of the junctional complex and discover how they contribute to cellular movement in the body.
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