Ultrafiltration refers to the filtration of very fine particles having mol.wt. less than 68KDa through the malpighian corpuscle.
A concentration of urine refers to water absorption from glomerular filtrate as a result of hyperosmolarity in the medulla created by counter-current mechanism in Henle’s loop.
The ureters are responsible for the transportation of urine from the kidney to the bladder.
The urinary bladder is concerned with the storage of urine.
The proximal convoluted tubule is concerned with the selective reabsorption of nutrients.