Differentiate between Glomerular filtration rate (GFR) and transport maximum (Tm).

Hint: The process of elimination of metabolic waste from the body of an organism is known as the excretion. Kidney is the main excretory organ inside the human body. Nephrons are present inside the kidney and are also referred to as the functional unit of kidney.

Complete answer:
Glomerular filtration rate or GFR is referred to as the amount of glomerular filtrate formed in all the renal corpuscles of the nephron present in both the kidneys per unit. In a healthy individual, the glomerular filtration rate is about 125ml per minute. The glomerular filtrate contains glucose, amino acids, sodium, potassium, urea, uric acid, ketone bodies along with a large amount of water. It occurs in the glomerulus.
On the other hand, transport maximum or Tm refers to the maximum rate at which substances can be transferred from the interstitial fluid to the tubular luminal fluid or from the tubular luminal fluid to the interstitial fluid. It is typically represented in milligrams per minute and is carried out via renal tubules. After this, the further excretion may occur in urine. It is usually expressed as Tm in the functional tests of kidneys. It occurs in the tubular cells.

Note: Glomerulus is present inside the nephron and it is a coiled structure having capillary walls. After filtration, the glomerular filtrate which consists of water and other soluble substances enters a cup-like sac known as the Bowman’s capsule. The filtrate is then transported to the renal tubule present in the nephron.