Cell Junctions Diagram – Tight, Adherens, Gap, Desmosome

All 13 parts on the diagram

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Start here: the junctions 5

Tight junction A seal between two cells near their free surface. It keeps molecules from slipping between them.
Adherens junction An anchoring junction tied to actin filaments. Cadherins hold the two cells together across the gap.
Desmosome A spot that holds two cells tightly together. Its plaques are tied to intermediate filaments.
Gap junction A patch of channels between two cells. Ions and small molecules pass straight from cytoplasm to cytoplasm.
Hemidesmosome Half of a desmosome, at the foot of a cell. It holds the cell to the basement membrane.

What they are built from 8

Claudins Small membrane proteins of the tight junction. They pull the two membranes into close contact.
Cadherins Membrane proteins that bind to each other across the gap. Adherens junctions and desmosomes both use them.
Actin filaments Thin filaments of the cytoskeleton. In an adherens junction, linker proteins tie them to the cadherins.
Plaque A dense plate of protein inside the membrane. It joins the cadherins to the filaments.
Intermediate filaments Strong, stable filaments of the cytoskeleton, made of keratin in epithelial cells. They loop into the plaque.
Connexon A ring of six connexin proteins. Two connexons end to end make one channel.
Integrins Membrane proteins of the hemidesmosome. They reach from the plaque into the basement membrane.
Basement membrane The thin layer that epithelial cells sit on. It is also called the basal lamina.

How this list was compiled: Every name was checked on 2026-10-01 and kept only where two independent sources use it. (1) Wikipedia, text only: Cell junction, https://en.wikipedia.org/wiki/Cell_junction ; Tight junction; Adherens junction; Desmosome; Gap junction; Hemidesmosome. (2) Kimball's Biology Pages, Junctions Between Cells, https://www.biology-pages.info/J/Junctions.html . (3) E. V. Wong, Cells: Molecules and Mechanisms, chapter 13, Extracellular Matrix and Cell Adhesion, an open college textbook, https://bio.libretexts.org/Bookshelves/Cell_and_Molecular_Biology/Cells_-_Molecules_and_Mechanisms_(Wong)/13%3A_Extracellular_Matrix_and_Cell_Adhesion . Licence: own work

The drawing: Drawn for this site on 2026-10-01 from plain geometry; nothing traced. Licence: own work

How it works

Cell junctions are the connections between neighboring animal cells. The first drawing shows two epithelial cells with the junctions in order from the free surface down. The second enlarges each junction to show its important components.

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Three jobs

A tight junction seals the space between cells. Adherens junctions, desmosomes and hemidesmosomes anchor: each ties the membrane to filaments inside the cell. A gap junction is a set of channels, so it lets cells share ions and small molecules.

Which filament goes with which

Adherens junctions are tied to thin actin filaments. Desmosomes and hemidesmosomes are tied to thick intermediate filaments through a dense plaque.

Hemi means half: a hemidesmosome has one plaque, and it faces the basement membrane, not another cell.

Questions and answers

What are the types of cell junctions?

Animal cells have tight junctions, which seal; anchoring junctions, which are the adherens junction, the desmosome and the hemidesmosome; and gap junctions, which are channels from one cell into the next.

What is the difference between a desmosome and a hemidesmosome?

A desmosome joins two cells, and its links across the gap are cadherins. A hemidesmosome joins one cell to the basement membrane, and its links are integrins. Both have a dense plaque tied to intermediate filaments.

What is the difference between a tight junction and a gap junction?

A tight junction closes the space between two cells, so little can pass between them. A gap junction does the opposite job: its channels open a path from the cytoplasm of one cell into the cytoplasm of the next.

What is a connexon?

It is half of a gap junction channel. Six connexin proteins form a ring, the connexon, in the membrane of one cell. It lines up with a connexon in the next cell, and the two make one open channel.