Difference Between Bowman’s Capsule and Malpighian Capsule

Main Difference – Bowman’s Capsule vs Malpighian Capsule

The kidney is the main organ which removes nitrogenous wastes from the blood while balancing the body fluids.  Urine is the excretory product of the kidney. The microscopic functional unit of the kidney is the nephron. About one million nephrons occur per a kidney. Renal corpuscle and renal tubule are the two main structural components of  a nephron. Renal corpuscle is composed of a Bowman’s capsule and glomerulus. Renal tubule is composed of  proximal and distal convoluted tubules, loop of Henle, and a collecting duct. Renal corpuscle is also called the Malpighian capsule. The main difference between Bowman’s capsule and Malphigian capsule is that Bowman’s capsule receives the filtrate of the glomerulus whereas Malpighian capsule filters blood.

Key Areas Coved

1. What is Bowman’s Capsule
      – Definition, Anatomy, Physiology
2. What is Malpighian Capsule
      – Definition, Anatomy, Physiology
3. What are the Similarities Between Bowman’s Capsule and Malpighian Capsule
      – Outline of Common Features
4. What is the Difference Between Bowman’s Capsule and Malpighian Capsule
      – Comparison of Key Differences

Key Terms: Bowman’s Capsule, Filtration of Blood, Glomerulus, Malpighian Capsule, Nephron, Renal Corpuscle, Renal Tubule

What is Bowman’s Capsule

Bowman’s capsule refers to a membranous, double-walled cup-like structure, which surrounds the glomerulus of a nephron. It is a part of the renal corpuscle, which is the initial structural component of a nephron. Bowman’s capsule is made up of two layers of epithelial cells. The glomerulus is encircled by the inner layer of the Bowman’s capsule. The blood plasma that is filtered by the glomerulus is received by the space between the double-membrane structure of the Bowman’s capsule. The outer layer of the Bowman’s capsule is continuous with the renal tubule. The structure of a nephron is shown in figure 1.

Figure 1: A Nephron

Vascular pole and urinary pole are the two sides of the Bowman’s capsule. The Vascular pole is the side that contains the afferent and efferent arterioles. The urinary pole is the side that contains the proximal convoluted tubule.

What is Malpighian Capsule

Malpighian capsule refers to the blood filtering component of the kidney. It is also called the renal corpuscle. The main function of the Malpighian capsule is the filtration of blood. The two components of the Malpighian capsule are the Bowman’s capsule and the glomerulus. The structure of the Malpighian capsule is shown in figure 2.

Figure 2: Malpighian Capsule

A – Renal corpuscle, B – Proximal tubule, C – Distal convoluted tubule, D – Juxtaglomerular apparatus

1. Basement membrane (Basal lamina), 2. Bowman’s capsule – parietal layer, 3. Bowman’s capsule – visceral layer, 3a. Pedicels (Foot processes from podocytes), 3b. Podocyte, 4. Bowman’s space (urinary space), 5a. Mesangium – Intraglomerular cell, 5b. Mesangium – Extraglomerular cell, 6. Granular cells (Juxtaglomerular cells), 7. Macula densa, 8. Myocytes (smooth muscle), 9. Afferent arteriole, 10. Glomerulus Capillaries, 11. Efferent arteriole

Glomerulus is the cluster of small blood capillaries of the Malpighian capsule, which filters the blood plasma. It is encircled by the Bowman’s capsule. The afferent arteriole, which is a branch of the renal vein, supplies blood to the glomerulus. The efferent arteriole, which is a branch of the renal artery, drains blood from the glomerulus. The two types of cells associated with the glomerular blood capillaries are podocytes and mesangial cells. Podocytes regulate the filtration of blood while mesangial cells remove trapped protein clusters within the blood capillaries.

Similarities Between Bowman’s Capsule and Malpighian Capsule

• Bowman’s capsule and Malpighian capsule are two components of a nephron.
• Both Bowman’s capsule and Malpighian capsule are made up of simple cuboidal epithelium.
• Both Bowman’s capsule and Malpighian capsule are involved in the filtration of blood.

Difference Between Bowman’s Capsule and Malpighian Capsule

Definition

Bowman’s Capsule: Bowman’s capsule refers to a membranous, double-walled cup-like structure, which surrounds the glomerulus of a nephron.

Malpighian Capsule: Malpighian capsule refers to the blood filtering component of the kidney.

Eponym

Bowman’s Capsule: Bowman’s capsule is named after Sir William Bowman (1816–1892).

Malpinghian capsule: Malpighian corpuscle is named after Marcello Malpighi (1628–1694).

Significance

Bowman’s Capsule: Bowman’s capsule is the cup-shaped structure, which is continuous with the renal tubule.

Malpighian Capsule: Bowman’s capsule and glomerulus are collectively called the Malpighian capsule.

Function

Bowman’s Capsule: Bowman’s capsule receives the filtrate of the glomerulus.

Malpighian Capsule: Malpighian capsule filters the blood and passes the filtrate to the renal tubule.

Conclusion

Bowman’s capsule and Malpighian capsule are two structures of a nephron. Both Bowman’s capsule and malpinghian capsule are involved in the filtration of blood. Bowman’s capsule receives the filtrate of the glomerulus. Malpinghian capsule consists of Bowman’s capsule and glomerulus. It filters blood and pass the filtrate to the renal tubule. The main difference between Bowman’s capsule and malpinghian capsule is the structure and the function of each structure in a nephron.

Reference:

1. “Bowman’s Capsule.” InnerBody, Available here.
2. “Renal corpuscle.” Encyclopædia Britannica, Encyclopædia Britannica, inc., 26 Aug. 2014, Available here.

Image Courtesy:

1. “2611 Blood Flow in the Nephron” By OpenStax College – Anatomy & Physiology, Connexions Web site, Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia
2. “Renal corpuscle” By  Michał Komorniczak (CC BY-SA 3.0) via Commons Wikimedia