List of human cell types explained

See also: Cell type. The list of human cell types provides an enumeration and description of the various specialized cells found within the human body, highlighting their distinct functions, characteristics, and contributions to overall physiological processes. Cells may be classified^[1] by their physiological function, histology (microscopic anatomy),^[2] lineage, or gene expression.

Total number of cells

The adult human body is estimated to contain about 30 trillion (3×10¹³) human cells, with the number varying between 20 and 40 trillion depending on factors such as sex, age, and weight. Additionally, there are approximately an equal number of bacterial cells. The exact count of human cells not yet been empirically measured in its entirety and is based on smaller samples of empirical observation.^{[3] [4] [5] [6] [7] [8]} It is generally assumed that these cells share features with each other and thus may be organized as belonging to a smaller number of types.^{[9] [10]}

Classification

As a definition of "cell type" is yet to be agreed, it is not possible yet to arrive at a precise number of human cell types.^[11] There is, for example, significant variation in these cell types depending on the specific surface proteins they possess.

An extensive listing of human cell types was published by Vickaryous and Hall in 2006, collecting 411 different types of human cells (with 145 types of neuron among those).

The Human Cell Atlas project, which started in 2016, had as one of its goals to "catalog all cell types (for example, immune cells or brain cells) and sub-types in the human body".^[12] By 2018, the Human Cell Atlas description based the project on the assumption that "our characterization of the hundreds of types and subtypes of cells in the human body is limited", but the word hundreds was removed in later versions.^[13]

On 2021, Stephen Quake guessed that the upper limit of the number of human cell types would be around 6000, based on a reasoning that "if biologists had discovered only 5% of cell types in the human body, then the upper limit of cell types to discover is somewhere around 6000 (i.e., 300/0.05)."

Other different efforts have used different numbers. A count of cells in the human body published in 2023 divided the cells in about 400 types to perform the calculation.

The main cellular components of the human body by count

	Cell type	% cell count
	Erythrocytes (red blood cells)	84.0
	Platelets	4.9
	Bone marrow cells	2.5
	Vascular endothelial cells	2.1
	Lymphocytes	1.5
	Hepatocytes	0.8
	Neurons and glia	0.6
	Bronchial endothelial cells	0.5
	Epidermal cells	0.5
	Respiratory interstitial cells	0.5
	Adipocytes (fat cells)	0.2
	Dermal fibroblasts	0.1
	Muscle cells	0.001
	Other cells	2.0

In 1996, scientists revealed a 'map' of 16,000 human genes.^[14] This led to estimates that humans likely had around 100 000 genes^[15] (or regions that code for human proteins). However, actual sequencing did not start before around 1999, and it was not until 2003^[16] that the first complete draft of a human genome revealed that there was roughly 20000-25000 protein-coding genes, as most DNA does not code for any protein. It is difficult to say that there have not been similar mistakes when estimating how many cells humans have as there are still substantial gaps in understanding human cells.

Efforts to characterize all human cell types

Several efforts have been made to make a list or a map of all human cells.^{[17] [18] [19]} One of the largest and most recent is the HuBMAP (Human BioMolecular Atlas Program).^[20]

The HuBMAP project has organized 1551 different samples in 17 collections, each dedicated to a different system. However, this project still only mapped about 31 of the human bodies' 70 organs. Their datasets and visualisations place great emphasis on biomarkers and location in the body, but less on cell development and how cells can change over time. Usually specific surface proteins are used to identify cells, and based on this they are put into different categories.

Another major effort to make an overview of these proteins that allows us to observe cell types is the Human Protein Atlas.^[21]

A similar project, the Human Brain Project has also attempted to map the human brain, although much of the publicly accessible model does not have cellular resolution.^{[22] [23]}

Standards and naming conventions

So far not all cells which can be found in the human body have been documented. There is no good way to make the experiment where one checks if all cell types identified so far could be taken from and measured in a single donor, proving that the cells types are universal to all humans. This is partly due to a lack of standards, as scientists are still not entirely sure what is needed to measure, in order to capture every cell type which can be found.

Some attempts have been made – and some are still in progress– for creating standards for identifying cells consistently.^{[24] [25] [26]} The Cell Ontology provides arguably the most comprehensive metadata standard to date, cataloging over 2500 cell classes and being used actively by the Human Cell Atlas community.^[27]

There is still no standard which are used industry wide, nor any definitions which have been accepted by the wider scientific community. Often making it difficult to say whether some collected and observed cells are really one or multiple types of cells. This lack of standards makes it difficult to estimate how many cell types and how many of each cell types can be found in the human body, as well as difficult to predict which young cells one would need to develop with mature cells. The list on this Wikipedia article also suffers to some inconsistencies due to multiple sources using different conventions.

List of human cell types

Cell type	Develops from	Tissue of origin	Function	Group ^[28]	Subgroup	Germ layer of origin	Biomarkers
Brunner's gland cell	crypt basal stem cells	in duodenum, duodenal submucosa	enzyme and alkaline mucus secretion	Exocrine secretory epithelial cells		Endoderm
		respiratory and digestive tracts	mucus secretion
		stomach
			pepsinogen secretion
			hydrochloric acid secretion
Pancreatic acinar cell		pancreas	bicarbonate and digestive enzyme secretion
			lysozyme secretion
Type II pneumocyte		lungs	surfactant secretion
Type I pneumocyte			formation of the Blood-Gas Barrier	Barrier cell
Gall bladder epithelial cell		gall bladder
Centroacinar cell		pancreas
Intestinal brush border cell (with microvilli)
K cell			gastric inhibitory peptide secretion	Hormone-secreting cells	Enteroendocrine cell
L cell			glucagon-like peptide-1, peptide YY3-36, oxyntomodulin, and glucagon-like peptide-2) secretion
I cell			cholecystokinin (CCK) secretion
G cell			gastrin secretion
Enterochromaffin cell			serotonin secretion
Enterochromaffin-like cell			histamine secretion
N cell			neurotensin secretion
S cell			secretin secretion
D cell			somatostatin secretion
Mo cell (or M cell)			motilin secretion
other hormones secreted: vasoactive intestinal peptide, substance P, alpha and gamma-endorphin, bombesin
Thyroid epithelial cell					Thyroid gland cells
Parafollicular cell
Parathyroid chief cell					Parathyroid gland cells
Oxyphil cell
Alpha cell			glucagon secretion		Pancreatic islets (islets of Langerhans)
Beta cell			insulin and amylin secretion
			somatostatin secretion
Epsilon cell			ghrelin secretion
PP cell (gamma cell)			pancreatic polypeptide secretion
Salivary gland mucous cell				Exocrine secretory epithelial cells		Ectoderm
Salivary gland serous cell
Von Ebner's gland cell		in tongue	(washes taste buds)
Mammary gland cell			(milk secretion)
			(tear secretion)
Ceruminous gland cell			(earwax secretion)
Eccrine sweat gland dark cell			(glycoprotein secretion)
Eccrine sweat gland clear cell			(small molecule secretion)
Apocrine sweat gland cell			(odoriferous secretion, sex-hormone sensitive)
Gland of Moll cell in eyelid			(specialized sweat gland)
Sebaceous gland cell			(lipid-rich sebum secretion)
Bowman's gland cell			(washes olfactory epithelium)
Corticotropes				Hormone-secreting cells	Anterior/Intermediate pituitary cells
Gonadotropes					Anterior/Intermediate pituitary cells
Lactotropes					Anterior/Intermediate pituitary cells
Melanotropes					Anterior/Intermediate pituitary cells
Somatotropes					Anterior/Intermediate pituitary cells
Thyrotropes					Anterior/Intermediate pituitary cells
Magnocellular neurosecretory cells			secrete oxytocin and vasopressin
Parvocellular neurosecretory cells			secrete thyrotropin-releasing hormone (TRH), corticotropin-releasing hormone (CRH), vasopressin, oxytocin, neurotensin, and prolactin
Chromaffin cells (adrenal gland)
				Epithelial cells
Epidermal basal cell (stem cell)
Melanocyte
Trichocyte
Medullary hair shaft cell	Trichocyte
Cortical hair shaft cell	Trichocyte
Cuticular hair shaft cell	Trichocyte
Huxley's layer hair root sheath cell	Trichocyte
Henle's layer hair root sheath cell	Trichocyte
Outer root sheath hair cell	Trichocyte
Surface epithelial cell		cornea, tongue, mouth, nasal cavity, distal anal canal, distal urethra, and distal vagina
basal cell (stem cell)		cornea, tongue, mouth, nasal cavity, distal anal canal, distal urethra, and distal vagina
Striated duct cell		(salivary glands)
Lactiferous duct cell		(mammary glands)
Ameloblast		(deposit tooth enamel)
			(tooth dentin formation)	Oral cells
Cementoblast			(tooth cementum formation)
				Sensory transducer cells
Auditory outer hair cells of organ of Corti
Cold-sensitive primary sensory neurons
Heat-sensitive primary sensory neurons
Merkel cells of epidermis
Olfactory receptor neurons
Pain-sensitive primary sensory neurons
Photoreceptor rod cells					Photoreceptor cells of retina in eye
Photoreceptor blue-sensitive cone cells of eye					Photoreceptor cells of retina in eye
Photoreceptor green-sensitive cone cells of eye					Photoreceptor cells of retina in eye
Photoreceptor red-sensitive cone cells of eye					Photoreceptor cells of retina in eye
Proprioceptive primary sensory neurons
Touch-sensitive primary sensory neurons
			(blood pH sensor)
Outer hair cells of vestibular system of ear			(acceleration and gravity)
Inner hair cells of vestibular system of ear
Taste receptor cells of taste bud
				Autonomic neuron cells
Adrenergic neural cells (various types)
Peptidergic neural cells (various types)
				Sense organ and peripheral neuron supporting cells
Outer pillar cells of the organ of Corti
Inner phalangeal cells of organ of Corti
Outer phalangeal cells of organ of Corti
Border cells of organ of Corti
Hensen's cells of organ of Corti
Vestibular apparatus supporting cells
Taste bud supporting cells
Olfactory epithelium supporting cells
Olfactory ensheathing cells
Schwann cells
Satellite glial cells
Enteric glial cells
Basket cells		Central nervous system neurons and glial cells		Neuron	Interneurons
Cartwheel cells					Interneurons
Stellate cells					Interneurons
Golgi cells					Interneurons
Granule cells					Interneurons
Lugaro cells					Interneurons
Unipolar brush cells					Interneurons
Martinotti cells					Interneurons
Chandelier cells					Interneurons
Cajal–Retzius cells					Interneurons
Double-bouquet cells					Interneurons
Neurogliaform cells					Interneurons
Retina horizontal cells					Interneurons
Starburst amacrine cells					Interneurons - > Amacrine cells
Renshaw cells					Interneurons - >Spinal interneurons
Spindle neurons					Principal cells
Fork neurons					Principal cells
Place cells					Principal cells-> Pyramidal cells
Grid cells					Principal cells-> Pyramidal cells
Speed cells					Principal cells-> Pyramidal cells
Head direction cells					Principal cells-> Pyramidal cells
Betz cells					Principal cells-> Pyramidal cells
Boundary cells					Principal cells->Stellate cells
Bushy cells					Principal cells
Purkinje cells					Principal cells
Medium spiny neurons					Principal cells
Astrocytes
Oligodendrocytes
Tanycytes				Ependymal cells
Pituicytes
Anterior lens epithelial cell				Lens cells
Crystallin-containing lens fiber cell
		Right atrium, atrioventricular junction, left atrium, left ventricle, right ventricle, epicardium	Myocardium, atriventricular node	Metabolism and storage cells	Adipocytes	Mesoderm	(gene:)FASN, GPAM, LEP,^[29]
Brown fat cell
Liver lipocyte
Cells of the Zona glomerulosa			produce mineralocorticoids	Secretory cells	Cells of the adrenal cortex
Cells of the Zona fasciculata			produce glucocorticoids
Cells of the zona reticularis			produce androgens
			secreting estrogen
Corpus luteum cell		ruptured ovarian follicle	secreting progesterone
Granulosa lutein cells					Corpus luteum cell
Theca lutein cells
Leydig cell			secreting testosterone
Seminal vesicle cell			(secretes seminal fluid components, including fructose for swimming sperm)
Prostate gland cell			(secretes seminal fluid components)
Bulbourethral gland cell			(mucus secretion)
Bartholin's gland cell			(vaginal lubricant secretion)
Gland of Littré cell			(mucus secretion)
Uterus endometrium cell			(carbohydrate secretion)
Juxtaglomerular cell			(renin secretion)
Macula densa cell		kidney
			Urinary system	Barrier cells
Podocyte
Proximal tubule brush border cell
Loop of Henle thin segment cell
Kidney distal tubule cell
Principal cell					Kidney collecting duct cell
Intercalated cell				Epithelial / Barrier cells		Mesoderm
		urinary bladder		Barrier cells		Mesoderm
Duct cell		seminal vesicle, prostate gland, and similar	Reproductive system	Barrier cells
Efferent ducts cell
Epididymal principal cell
Epididymal basal cell
Endothelial cells		circulatory system					ABCC9, KCNJ8, RGS5
Planum semilunar epithelial cell of vestibular system of ear			(proteoglycan secretion)	Extracellular matrix cells
Organ of Corti interdental epithelial cell			(secreting tectorial membrane covering hair cells)
Loose connective tissue fibroblasts
Corneal fibroblasts			(corneal keratocytes)
Tendon fibroblasts
Bone marrow reticular tissue fibroblasts
Other nonepithelial fibroblasts
Hepatic stellate cell (Ito cell)		liver			Pericyte
		intervertebral disc
Hyaline cartilage chondrocyte
Fibrocartilage chondrocyte
Elastic cartilage chondrocyte
Osteoblast/osteocyte
		vitreous body of eye
Stellate cell
Pancreatic stellate cell
Red skeletal muscle cell (slow twitch)				Contractile cells	Skeletal muscle cells
White skeletal muscle cell (fast twitch)
Intermediate skeletal muscle cell
		muscle spindle
		muscle spindle
Myosatellite cell (stem cell)
Cardiac muscle cell					Cardiac muscle cells
SA node cell
Purkinje fiber cell
Smooth muscle cell (various types)		iris
		exocrine glands
Erythrocyte (red blood cell)	erythroblasts				Blood and immune system cells
Megakaryocyte
Platelets if considered distinct cells, currently there's debate on the subject.
Monocyte (white blood cell)
Connective tissue macrophage (various types)
Epidermal Langerhans cell
		in bone
		central nervous system
	myeloblast, promyelocyte, myelocyte, metamyelocyte
Eosinophil granulocyte	myeloblast, promyelocyte, myelocyte, metamyelocyte
Basophil granulocyte	myeloblast, promyelocyte, myelocyte, metamyelocyte
Mast cell
Helper T cell
Regulatory T cell
Cytotoxic T cell
Natural killer T cell
B cell(/lymphocyte)		Left atrium, left ventricle, septum, right ventricle, epicaridum	Myocardium
Natural killer cell
Hematopoietic stem cells and committed progenitors for the blood and immune system (various types)
Oogonium/oocyte					Germ cells
Spermatid
Spermatocyte
Spermatozoon
		In the ovaries			Nurse cells
Sertoli cell		In the testis
Epithelial reticular cell		In the thymus
Interstitial kidney cells		Kidney			Interstitial cells

Cell type databases

Name	Provider	Sources of revenue/sponsors	Scope	Amount of cells identified so far
HubMap^[30]	A series of US based universities	Unknown		~1200
Human Cell Atlas	Columbia University Medical Center at Columbia University	Chan Zuckerberg Initiative	37 trillion cells
CellXgene^[31]		Chan Zuckerberg Initiative^[32]

Cells derived primarily from endoderm

The endodermal cells primarily generate the lining and glands of the digestive tube.^[33]

Cells derived primarily from ectoderm

Nervous system

There are nerve cells, also known as neurons, present in the human body. They are branched out. These cells make up nervous tissue.A neuron consists of a cell body with a nucleus and cytoplasm, from which long thin hair-like parts arise.

See also

• List of human cell types derived from the germ layers
• Human Cell Atlas
• Cell Ontology
• List of organs of the human body
• List of human microbiota

External links

• Human Cell Tree Map
• Human Cell Atlas

Notes and References

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2. Book: Khan YS, Farhana A . Histology, Cell . May 2023 . StatPearls [Internet] . Treasure Island (FL) . StatPearls Publishing . https://www.ncbi.nlm.nih.gov/books/NBK554382/ .
3. Hatton IA, Galbraith ED, Merleau NS, Miettinen TP, Smith BM, Shander JA . The human cell count and size distribution . Proceedings of the National Academy of Sciences of the United States of America . 120 . 39 . e2303077120 . September 2023 . 37722043 . 10523466 . 10.1073/pnas.2303077120 . 2023PNAS..12003077H .
4. Web site: 2023-09-19 . Mapping the human body one cell at a time: New study reveals the intricate relationship between cell size and count . 2023-10-18 . News-Medical.net . en.
5. Web site: Max Planck Society . Cellular cartography: Charting the sizes and abundance of our body's cells reveals mathematical order underlying life . 2023-10-18 . medicalxpress.com . en.
6. Sender R, Fuchs S, Milo R . Revised Estimates for the Number of Human and Bacteria Cells in the Body . PLOS Biology . 14 . 8 . e1002533 . August 2016 . 27541692 . 4991899 . 10.1371/journal.pbio.1002533 . free .
7. Web site: Hewings-Martin Y . 12 July 2017 . How many cells are in the human body? . 28 June 2023 . Medical News Today . en.
8. Web site: Zimmer C . 23 October 2013 . How Many Cells Are In Your Body? . https://web.archive.org/web/20210403230815/https://www.nationalgeographic.com/science/article/how-many-cells-are-in-your-body . dead . April 3, 2021 . 29 June 2023 . National Geographic . en.
9. Quake SR . The cell as a bag of RNA . Trends in Genetics . 37 . 12 . 1064–1068 . December 2021 . 34462156 . 10.1016/j.tig.2021.08.003 . free .
10. Vickaryous MK, Hall BK . Human cell type diversity, evolution, development, and classification with special reference to cells derived from the neural crest . Biological Reviews of the Cambridge Philosophical Society . 81 . 3 . 425–455 . August 2006 . 16790079 . 10.1017/S1464793106007068 .
11. What Is Your Conceptual Definition of 'Cell Type' in the Context of a Mature Organism? . Cell Systems . March 2017 . 4 . 3 . 255–259 . 10.1016/j.cels.2017.03.006 . 28334573 .
12. Web site: 2022-10-01 . HCA – Human Cell Atlas . 2024-06-14 . https://web.archive.org/web/20221001200439/https://www.humancellatlas.org/learn-more/ . 2022-10-01 .
13. Web site: 2018-08-29 . Human Cell Atlas - Human Cell Atlas . 2024-06-14 . https://web.archive.org/web/20180829033849/https://www.humancellatlas.org/learn-more . 2018-08-29 .
14. Web site: The Human Transcript Map . 2024-04-23 . www.ncbi.nlm.nih.gov.
15. Amaral P, Carbonell-Sala S, De La Vega FM, Faial T, Frankish A, Gingeras T, Guigo R, Harrow JL, Hatzigeorgiou AG, Johnson R, Murphy TD, Pertea M, Pruitt KD, Pujar S, Takahashi H, Ulitsky I, Varabyou A, Wells CA, Yandell M, Carninci P, Salzberg SL . The status of the human gene catalogue . Nature . 622 . 7981 . 41–47 . October 2023 . 37794265 . 10575709 . 10.1038/s41586-023-06490-x . 2303.13996 . 2023Natur.622...41A .
16. Web site: Why the human genome was never completed . 2024-04-23 . www.bbc.com.
17. Web site: Home . 5 May 2023 . humancellatlas.org . en-GB.
18. Web site: 26 September 2018 . NIH to build a detailed map of cells within the human body . 5 May 2023 . National Institutes of Health (NIH) . EN.
19. Web site: Davis D . The ambitious quest to map every cell in our body . 5 May 2023 . BBC . en.
20. Web site: HuBMAP Consortium . The HuBMAP Human BioMolecular Atlas Program . 5 May 2023 . en-US.
21. Web site: The Human Protein Atlas . 19 July 2023 . www.proteinatlas.org.
22. Web site: Siibra Explorer . 2023-07-02 . atlases.ebrains.eu.
23. Web site: Medical Data Analytics . 2 July 2023 . The Human Brain Project .
24. Preprint . Lubiana T, Roncaglia P, Mungall CJ, Quardokus EM, Fortriede JD, Osumi-Sutherland D, Diehl AD . Guidelines for reporting cell types: the MIRACL standard . 2022 . 2204.09673 .
25. Ascoli GA, Alonso-Nanclares L, Anderson SA, Barrionuevo G, Benavides-Piccione R, Burkhalter A, Buzsáki G, Cauli B, Defelipe J, Fairén A, Feldmeyer D, Fishell G, Fregnac Y, Freund TF, Gardner D, Gardner EP, Goldberg JH, Helmstaedter M, Hestrin S, Karube F, Kisvárday ZF, Lambolez B, Lewis DA, Marin O, Markram H, Muñoz A, Packer A, Petersen CC, Rockland KS, Rossier J, Rudy B, Somogyi P, Staiger JF, Tamas G, Thomson AM, Toledo-Rodriguez M, Wang Y, West DC, Yuste R . Petilla terminology: nomenclature of features of GABAergic interneurons of the cerebral cortex . Nature Reviews. Neuroscience . 9 . 7 . 557–568 . July 2008 . 18568015 . 2868386 . 10.1038/nrn2402 . 10261/36813 .
26. Web site: Home . 2024-04-23 . www.humancellatlas.org . en-GB.
27. Osumi-Sutherland D, Xu C, Keays M, Levine AP, Kharchenko PV, Regev A, Lein E, Teichmann SA . Cell type ontologies of the Human Cell Atlas . Nature Cell Biology . 23 . 11 . 1129–1135 . November 2021 . 34750578 . 10.1038/s41556-021-00787-7 .
28. The organization of the cell types in a hierarchy of groups and subgroups is done for organization purposes and does not conform to any particular standard.
29. Web site: CCF ASCT+B Reporter . Hubmap Consortium.
30. Web site: 5 January 2017 . The Human BioMolecular Atlas Program (HuBMAP) . 2023-07-12 . commonfund.nih.gov . en.
31. Web site: CellGuide Cell Types and Cell Tissues - CZ CELLxGENE . 2024-07-05 . Cellxgene Data Portal.
32. Web site: Behind the scenes of Chan Zuckerberg CELLxGENE . 2024-07-05 . Chan Zuckerberg Initiative . en-US.
33. Book: Gilbert . Scott F. . Endoderm . https://www.ncbi.nlm.nih.gov/books/NBK10107/ . Developmental Biology . 2000 . Sinauer Associates . 978-0-87893-243-6 . 6th .