Cell-Cell Junctions and Adhesion

Study Notes

Cell-Cell Adhesion and Junctions

Cells cling to each other through two main ways: direct cell-cell junctions and extracellular matrix
Direct cell-cell junctions:
- Create pathways for communication between cells
- Allow cells to exchange signals that coordinate their behavior
- Regulate patterns of gene expression
Extracellular matrix:
- Composed of extracellular materials secreted by cells
- Controls the orientation of cells' internal structure

Functional Classes of Cell Junctions

There are four functional classes of cell junctions in animal tissues
These classes include both cell-cell junctions and cell-matrix adhesions
Functions of these classes:
- Transmit stresses and are tethered to cytoskeletal filaments inside the cell
- Seal the gap between cells in the epithelia to create an impermeable barrier
- Create passageways linking the cytoplasm of adjacent cells
- Allow signals to be relayed from cell to cell across their plasma membranes

Specific Types of Cell Junctions

Examples of cell junctions:
- Chemical synapses in the nervous system
- Immunological synapses, where T-lymphocytes interact with antigen-presenting cells
Epithelial cells have specific types of cell junctions that play a crucial role in forming a barrier

Classification of Cell Junctions

Cell junctions can be functionally classified into different types, as shown in Table 19-1
This classification is important for understanding the roles of cell junctions in different tissues and cells.

Description

This quiz covers the different ways cells adhere to each other, including direct cell-cell junctions and extracellular matrix. It also explores the functional classes of cell junctions in animal tissues.