Parietal Cell Diagram – Canaliculus and Proton Pump Labeled

All 12 parts on the diagram

Show the list

The cell 6

Nucleus The nucleus sits in the middle of the cell. The canaliculus forks around it.
Canaliculus A deep channel folded in from the top of the cell. Acid is secreted into it.
Tubulovesicles Small sacs of membrane that store proton pumps. They join the canaliculus when the cell is active.
Mitochondria The many oval bodies that supply the energy for pumping acid.
Apical membrane (lumen side) The side of the cell that faces the lumen of the gland.
Basolateral membrane (blood side) The sides and base of the cell, facing the blood supply.

Making acid 6

Proton pump (H+/K+ ATPase) Pumps hydrogen ions out of the cell and takes potassium ions in.
Chloride channel Lets chloride ions out to the lumen. It sits in the top membrane.
Hydrochloric acid The acid of the stomach. Hydrogen and chloride ions from the cell form it.
Carbonic anhydrase An enzyme that joins carbon dioxide and water. A hydrogen ion and bicarbonate come of it.
Chloride-bicarbonate exchanger Swaps bicarbonate out to the blood for chloride coming in.
Intrinsic factor A protein the parietal cell also secretes. The body needs it to absorb vitamin B12.

How this list was compiled: Every name read on 2026-10-03 and kept only where two independent sources give it. (1) Wikipedia, text only: Parietal cell, https://en.wikipedia.org/wiki/Parietal_cell . (2) Colorado State University, Vivo Pathophysiology: The Parietal Cell, Mechanism of Acid Secretion, http://www.vivo.colostate.edu/hbooks/pathphys/digestion/stomach/parietal.html , and Gastric Secretions, http://www.vivo.colostate.edu/hbooks/pathphys/digestion/stomach/secretion.html (both read in the Internet Archive copy): canaliculi, tubulovesicular membranes, the proton pump, carbonic anhydrase, chloride channels, the exchange of bicarbonate for chloride at the basolateral membrane, intrinsic factor. (3) Miller and others, Journal of Biomedicine and Biotechnology (2010), open access, https://europepmc.org/article/PMC/PMC2842899 : canaliculi, tubulovesicles, mitochondria, nucleus, apical and basolateral membranes, the chloride-bicarbonate exchanger. (4) Nighot and others, PLoS One (2015), open access, https://europepmc.org/article/PMC/PMC4574764 : a chloride channel in the parietal cell, tubulovesicles joining the apical membrane. (5) Henry Gray, Anatomy of the Human Body (1918, public domain), The Stomach, https://www.theodora.com/anatomy/the_stomach.html : parietal or oxyntic cells joined to the lumen by fine channels. The drawing is our own. Licence: own work

The drawing: Drawn for this site on 2026-10-03 from plain geometry. Own original drawing; nothing traced or copied. Not to scale. Licence: own work

How it works

Parietal cells, also called oxyntic cells, sit in the gastric glands of the stomach and secrete hydrochloric acid and intrinsic factor. The first drawing shows one cell. The second is a chart of how it makes acid.

Read the full guide

The cell

The narrow top of the cell faces the lumen of the gland; its sides and base face the blood. The canaliculus is a deep channel folded in from the top. Tubulovesicles beside it join its membrane when the cell is active, and many mitochondria supply the energy.

Making acid

Carbonic anhydrase joins carbon dioxide and water, which gives a hydrogen ion and bicarbonate. The proton pump sends the hydrogen ion out in exchange for potassium. Bicarbonate leaves to the blood through an exchanger that brings chloride in, and chloride follows the hydrogen ion out through a channel.

For a parietal cells diagram that shows the whole gastric gland, open the stomach wall page.

Questions and answers

What does a parietal cell do?

It secretes hydrochloric acid into the stomach and a protein called intrinsic factor, which the body needs to absorb vitamin B12. Parietal cells are found in the gastric glands of the stomach lining.

What is the canaliculus of a parietal cell?

A deep infolding of the cell membrane that opens to the lumen of the gland. It greatly enlarges the surface that secretes acid. Tubulovesicles fuse with it when the cell is stimulated, so it grows and shrinks with need.

How does a parietal cell make hydrochloric acid?

Carbonic anhydrase forms hydrogen ions and bicarbonate from carbon dioxide and water. The proton pump moves hydrogen ions out in exchange for potassium, chloride ions follow through channels, and the two form hydrochloric acid. Bicarbonate leaves to the blood.

Why do parietal cells have so many mitochondria?

Pumping hydrogen ions out against a very steep gradient is active transport, driven by ATP. The many mitochondria of the cell supply that ATP to the proton pump.