Question

Indicate whether the given statement is true or false-
Protein free fluid is filtered from blood plasma into the bowman’s capsule.

Answer 1

Each kidney contains more than one million filtering units called nephrons. Within each tiny unit is a glomerulus where blood is filtered. The glomerulus is enveloped in a cup-shaped membrane known as Bowman's capsule. The filtrate contains urea, amino acid, creatinine, hormones, vitamins, salt/ions, glucose etc.

Complete answer:
The urine formation occurs in kidney tubules of nephrons or uriniferous tubules which are functional units of the kidney. The processes are ultra filtration, selective reabsorption and tubular secretion.
The first step in urine formation is ultra filtration and it occurs in the Malpighian corpuscles of nephrons. As we know, the diameter of the afferent arteriole entering the glomerulus is greater than that of the different arteriole leaving it, that means more blood enters than can leave. Since the walls of glomerulus and Bowman's capsule are extremely thin, permeable and in close contact, most of the constituents of blood, except the proteins, fats and cells are filtered into the cavity of the capsule. The mechanism is known as glomerular filtration or ultra filtration. Filtration occurs through tiny spaces amongst the cells of capillary walls and filtration slits of podocytes in the wall of Bowman's capsule.
The filtered out fluid is known as glomerular or capsular filtrate. It contains mostly urea dissolved in water besides glucose, amino-acid, sodium, potassium and other inorganic ions, uric acid, creatinine. The remaining constituents of blood i.e. cells, proteins and fats, pass on through the efferent arteriole without getting filtered. The glomerulus filter (GF) is thus blood-cells and proteins.

So, The above statement is true. The size of protein molecules is comparatively bigger that cannot be passed through glomerulus and Bowman's capsule.

Note: The functional unit of the kidney is the nephron. Each nephron consists of a Bowman's capsule, glomerulus and coiled renal tubule including Henle's loop. Urine formation is accomplished by filtration from blood plasma, reabsorption of useful materials and secretion of a few substances into renal tubules.