Distinguish Between Renal Corpuscle and Renal Tubule

Main Difference – Renal Corpuscle vs Renal Tubule

Nephron is the microscopic functional unit of the kidney, which is involved in the filtration of blood in order to remove excess water and salts along with the nitrogenous waste products of animals. Ideally, one million of nephrons can be identified in a kidney. A nephron is composed of a Bowman’s capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule, and a collecting duct. Bowman’s capsule encircles the glomerulus, which is a cluster of small blood vessels, carrying blood to the nephron. The components of a nephron can be grouped into renal corpuscle and renal tubule. Renal corpuscle consists of the glomerulus and the Bowman’s capsule whereas renal tubule consists of the parts of the nephron from the Bowman’s capsule to the collecting duct. Thus, the components of a nephron help to distinguish between renal corpuscle and renal tubule.

Key Areas Covered

1. What is Renal Corpuscle
      – Definition, Anatomy, Physiology
2. What is Renal Tubule
      – Definition, Anatomy, Physiology
3. What are the Similarities Between Renal Corpuscle and Renal Tubule
      – Outline of Common Features
4. What is the Difference Between Renal Corpuscle and Renal Tubule
      – Comparison of Key Differences

Key Terms: Afferent Arteriole, Bowman’s Capsule, Efferent Arteriole, Glomerulus, Nephron, Renal Corpuscle, Renal Tubule

What is Renal Corpuscle

Renal corpuscle refers to the cluster of glomerulus capillaries and the Bowman’s capsule, which encircles the glomerulus. Therefore, it is the initial part of a nephron. Renal corpuscle is an ovoid structure with a diameter around 150 μm to 250 μm. The glomerular capillaries arise from the afferent arteriole, which supplies blood to the glomerulus. Efferent arteriole takes blood away from the glomerulus. The cells that lies between glomerulus capillaries are called mesangial cells. The inner layer of the Bowman’s capsule is composed of podocytes. Podocytes are wrapped around the glomerulus capillaries by their foot-like structures. The structure of the renal corpuscle is shown in figure 1.

Figure 1: Renal Corpuscle

Filtration of blood is the main function of the renal corpuscle. During filtration, water, glucose, amino acids, ions, and other small molecules up to 40 kDa are filtered into the Bowman’s space, which is continuous with the proximal convoluted tubule of the nephron. Red blood cells, white blood cells, platelets and large proteins such as fibrinogens remain inside glomerulus capillaries.

What is Renal Tubule

Renal tubule refers to the long convoluted tubules, which transports urine from the glomeruli to the renal pelvis. It produces urine from the plasma filtrate. The structural parts of the renal tubule are the proximal convoluted tubule, loop of Henle, distal convoluted tubule, and the collecting duct. Different types of molecules are reabsorbed in the different parts of the renal tubule. Proximal convoluted tubule is located in the renal cortex and it mainly reabsorbs water, glucose, amino acids, and ions. The loop of Henle penetrates to the renal medulla. The descending limb of the loop of Henle reabsorbs water while the ascending limb of the loop of Henle reabsorbs sodium ions and chloride ions. The distal convoluted tubule is located in the renal medulla and it reabsorbs water and ions such as sodium, calcium, and chloride. Collecting duct is again located in the renal medulla, reabsorbing water and ions. The differential absorption occurs based on the type of epithelial cells in each part of the renal tubule. 

Figure 2: Renal Tubule

The loop of Henle is surrounded by a vascular network called vasa recta, which aids the reabsorption of molecules into the vascular system. The remaining filtrate in the collecting duct is called urine. Urine is mainly composed of water (91-96%). It also contains wastes products such as urea, uric acid, and creatinine. Organic compounds such as proteins, hormones, metabolites, and inorganic salts can be identified in urine as well.

Similarities Between Renal Corpuscle and Renal Tubule

• Both renal corpuscle and renal capsule are composed of different structures of a nephron.
• Most of the components of the renal corpuscle and renal tubule occur in the renal cortex excluding the loop of Henle and collecting duct.
• The main function of both renal corpuscle and renal tubule is the filtration of blood.

Difference Between Renal Corpuscle and Renal Tubule

Definition

Renal Corpuscle: Renal corpuscle refers to the cluster of glomerulus capillaries and the Bowman’s capsule, which encircles the glomerulus.

Renal Tubule: Renal tubule refers to the long, tiny, convoluted tubules, which carry urine from the glomeruli to the renal pelvis.  

Composition

Renal Corpuscle: Renal corpuscle is composed of the glomerulus and Bowman’s capsule.

Renal Tubule: Renal tubule is composed of proximal and distal convoluted tubules, loop of Henle, and collecting ducts.

Vasculature

Renal Corpuscle: The blood supply in the renal corpuscle occurs by afferent arteriole and efferent arteriole.

Renal Tubule: The blood supply in the renal tubule occurs through vasa recta.

Function

Renal Corpuscle: Filtration of blood occurs in the renal corpuscle.

Renal Tubule: Reabsorption and production of urine occur in the renal tubule.

Conclusion

Renal corpuscle and renal tubule are the two main components of a nephron. Renal corpuscle consists of glomerulus capillaries and Bowman’s capsule, which filters blood. Renal tubule consists of proximal and distal convoluted tubules, loop of Henle, and the collecting duct, which reabsorb important molecules from the glomerular filtrate. Thus, it’s the components of these structures that help to distinguish between renal corpuscle and renal tubule.

Reference:

1. Physiology Image: Renal corpuscle. – PhysiologyWeb, Available here.
2. Samuel, Leslie. NEPHRONS: FUNCTION OF THE VARIOUS SEGMENTS OF THE RENAL TUBULE, INTERACTIVE BIOLOGY, Available here.

Image Courtesy:

1. “2615 Juxtaglomerular Apparatus” By OpenStax Anatomy and Physiology (CC BY 4.0) via Commons Wikimedia
2. “Kidney-Tubules” By en:Henry Vandyke Carter – Gray’s Anatomy of the Human Body, 1918 (Public Domain) via Commons Wikimedia