The diagram given below is that of a structure present in a human kidney. Study the same and answer the questions that follow: The diagram given below is that of a structure present in a human kidney. Study the same and answer the questions that follow:
What is the liquid entering part ‘1’ called? Name two substances present in this liquid that are reabsorbed in the tubule.
Topic: Glomerular filtrate
Answer
The liquid is the GLOMERULAR FILTRATE (nephric filtrate or ultrafiltrate).
Two substances reabsorbed: GLUCOSE and WATER (also acceptable: amino acids, sodium chloride, sodium ions).
Both halves must be answered: the NAME of the liquid and TWO substances.
The glomerular filtrate is what is forced out of the glomerulus into Bowman’s capsule during ULTRAFILTRATION. It contains water, glucose, amino acids, urea and salts — everything small enough to pass — while blood cells and large plasma PROTEINS are held back.
WHY REABSORPTION IS NECESSARY: filtration is INDISCRIMINATE. It removes useful substances along with the wastes, so the tubule must then recover what the body needs. That is why the second step is called SELECTIVE reabsorption.
GLUCOSE is the best example: ALL of it is normally reabsorbed, which is why urine contains none. Glucose in the urine means there was more in the blood than the tubule could recover — the sign of diabetes mellitus.