kidney

In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood exits into the paired renal veins. Each kidney is attached to a ureter, a tube that carries excreted urine to the bladder.

AI overview

Your kidneys are two bean-shaped organs that filter waste and extra water from your blood to make urine. They're essential for removing these unwanted substances from your body and maintaining the right balance of water and chemicals in your bloodstream.

AI-generated from the Wikipedia summary — may contain errors.

Key facts

Anatomy.Name: Kidneys
Anatomy.Latin: ren
Anatomy.Greek: νεφρός (nephros)
Anatomy.Image: Blausen 0592 KidneyAnatomy 01.png
Anatomy.Caption: The kidneys lie in the retroperitoneal space behind the abdomen, and act to filter blood to create urine
Anatomy.Image2: Diagram showing the position of the adrenal glands CRUK 343.svg
Anatomy.Caption2: Location of kidneys with associated organs (adrenal glands and bladder)
Anatomy.System: Urinary system and endocrine system
Anatomy.Artery: Renal artery
Anatomy.Vein: Renal vein
Anatomy.Nerve: Renal plexus

via Wikipedia infobox

Research

1,144,228 papers

SGLT2 Inhibitors and Kidney Protection: Mechanisms Beyond Tubuloglomerular Feedback.ReviewKidney360 · 2024Upadhyay ADOI: 10.34067/KID.0000000000000425
[The kidney, its anatomy and main functions].Soins. Gerontologie · 2024Levassort H, Essig MDOI: 10.1016/j.sger.2023.12.003
Lactate metabolism and lactylation in kidney diseases: insights into mechanisms and therapeutic opportunities.ReviewRenal failure · 2025Cheng Y, Guo LDOI: 10.1080/0886022X.2025.2469746
Flow-enhanced vascularization and maturation of kidney organoids in vitro.Nature methods · 2019Homan KA, Gupta N, Kroll KT et al.DOI: 10.1038/s41592-019-0325-y
Endothelial dysfunction in the aging kidney.ReviewAmerican journal of physiology. Renal physiology · 2025Borri M, Jacobs ME, Carmeliet P et al.DOI: 10.1152/ajprenal.00287.2024
Kidney clearance of fibroblast growth factor-23 in humans.ReviewCurrent opinion in nephrology and hypertension · 2023Sharma S, Ix JHDOI: 10.1097/MNH.0000000000000900
Autoantibody-triggered podocyte membrane budding drives autoimmune kidney disease.Cell · 2026Lahme K, Sachs W, Froembling S et al.DOI: 10.1016/j.cell.2025.11.010
Comparative single-cell analyses identify shared and divergent features of human and mouse kidney development.Developmental cell · 2024Kim S, Koppitch K, Parvez RK et al.DOI: 10.1016/j.devcel.2024.07.013

via PubMed

Wikidata facts

Image: Kidney section vertical.png

Show 3 more facts

Commons gallery: Kidney
NCI Thesaurus ID: C12415
Commons category: Kidneys

Sources (9)

via Wikidata · CC0

~35 min read

Article

41 sections

Contents

Structure
Gross anatomy
Blood supply
Nerve supply
Microanatomy
Gene and protein expression
Development
Function
Formation of urine
Filtration
Reabsorption
Secretion
Excretion
Hormone secretion
Blood pressure regulation
Acid–base balance
Regulation of osmolality
Measuring function
Clinical significance
Acquired disease
Kidney injury and failure
Dialysis
Congenital disease
Diagnosis
Imaging
Biopsy
Other animals
Evolutionary adaptation
Society and culture
Significance
Egyptian
Hebrew
India: Ayurvedic system
Medieval Christianity
History
Additional images
See also
References
Citations
General and cited references
External links

The kidney participates in the control of the volume of various body fluids, fluid osmolality, acid–base balance, various electrolyte concentrations, and removal of toxins. Filtration occurs in the glomerulus: one-fifth of the blood volume that enters the kidneys is filtered. Examples of substances reabsorbed are solute-free water, sodium, bicarbonate, glucose, and amino acids. Examples of substances secreted are hydrogen, ammonium, potassium and uric acid. The nephron is the structural and functional unit of the kidney. Each adult human kidney contains around 1 million nephrons, while a mouse kidney contains only about 12,500 nephrons. The kidneys also carry out functions independent of the nephrons. For example, they convert a precursor of vitamin D to its active form, calcitriol; and synthesize the hormones erythropoietin and renin.