nephron

Examples of nephron in the following topics:

• Nephron: The Functional Unit of the Kidney

  • The functional unit of the kidney, the nephron, removes waste from the body.
  • The nephron, the functional unit of the kidney, is responsible for removing waste from the body.
  • Eighty-five percent of nephrons are cortical nephrons, deep in the renal cortex; the remaining 15 percent are juxtamedullary nephrons, which lie in the renal cortex close to the renal medulla.
  • The nephron is the functional unit of the kidney.
  • Explain the role of the nephron as the functional unit of the kidney

• Internal Anatomy of the Kidneys

  • The cortex and medulla make up two of the internal layers of a kidney and are composed of individual filtering units known as nephrons.
  • The renal medulla contains the majority of the length of nephrons, the main functional component of the kidney that filters fluid from blood.
  • The cortex provides a space for arterioles and venules from the renal artery and vein, as well as the glomerular capillaries, to perfuse the nephrons of the kidney.
  • The medulla consists of multiple pyramidal tissue masses, called the renal pyramids, which are triangle structures that contain a dense network of nephrons.
  • At one end of each nephron, in the cortex of the kidney, is a cup-shaped structure called the Bowman's capsule.

• Nephron, Parts, and Histology

  • The nephron of the kidney is involved in the regulation of water and soluble substances in blood.
  • A nephron is the basic structural and functional unit of the kidneys that regulates water and soluble substances in the blood by filtering the blood, reabsorbing what is needed, and excreting the rest as urine.
  • The visceral layer lies just beneath the thickened glomerular basement membrane and only allows fluid and small molecules like glucose and ions like sodium to pass through into the nephron.
  • Approximately 2/3rds of water in the nephron and 100% of the glucose in the nephron are reabsorbed by cotransport in the proximal convoluted tubule.
  • The distal convoluted tubule and collecting duct is the final site of reabsorption in the nephron.

• Tubular Reabsorption

  • The fluid filtered from blood, called filtrate, passes through the nephron, much of the filtrate and its contents are reabsorbed into the body.
  • Reabsorption in the nephron may be either a passive or active process, and the specific permeability of the each part of the nephron varies considerably in terms of the amount and type of substance reabsorbed.
  • Water can follow other molecules that are actively transported, particularly glucose and sodium ions in the nephron.
  • As filtrate passes through the nephron, its osmolarity (ion concentration) changes as ions and water are reabsorbed.
  • A diagram of the nephron that shows the mechanisms of reabsorption.

• Glomerular Diseases

  • Glomerulopathy refers to a disease affecting the glomeruli of the nephron.
  • The nephron is a tubular structure in the kidney that filters blood to form urine.
  • The glomerulus, a network (tuft) of capillaries, is located at the beginning of the nephron, and performs the first step of filtering blood.
  • The Bowman's capsule empties the filtrate into a tubule that is also part of the nephron.
  • Glomerulopathy is a term used to describe a disease affecting the glomeruli of the nephron.

• Aging and the Urinary System

  • As kidneys age, the number of filtering units and nephrons decreases, slowing down kidney function.
  • The number of filtering units (nephrons) decreases.
  • Nephrons filter waste material from the blood.

• Bulk Flow: Filtration and Reabsorption

  • Blood that enters the kidneys is filtered by nephrons, the functional unit of the kidney.
  • Each nephron begins in a renal corpuscle composed of a glomerulus containing numerous capillaries enclosed in a Bowman's capsule.
  • Blood continues to flow around the nephron until it reaches another capillary-rich region the peritubular capillaries, where the previously filtered molecules are reabsorbed from the tubule of the nephron.

• Glomerular Filtration

  • Many of these materials are reabsorbed by the body as the fluid travels through the various parts of the nephron, but those that are not reabsorbed leave the body in the form of urine.
  • The visceral layer lies just beneath the thickened glomerular basement membrane and is made of podocytes that form small slits in which the fluid passes through into the nephron.
  • The force of hydrostatic pressure in the glomerulus (the force of pressure exerted from the pressure of the blood vessel itself) is the driving force that pushes filtrate out of the capillaries and into the slits in the nephron.
  • A diagram showing the afferent and efferent arterioles bringing blood in and out of the Bowman's capsule, a cup-like sac at the beginning of the tubular component of a nephron.

• Renal Clearance

  • Clearance is a function of glomerular filtration, secretion from the peritubular capillaries to the nephron, and reabsorption from the nephron back to the peritubular capillaries.

• Tubular Secretion

  • Passive diffusion—the movement of molecules from the peritubular capillaries to the intersitial fluid within the nephron.
  • Active transport—the movement of molecules via ATPase pumps that transport the substance through the renal epithelial cell into the lumen of the nephron.
  • Tubular secretion occurs throughout the different parts of the nephron, from the proximal convoluted tubule to the collecting duct at the end of the nephron.