Omar accompanied his uncle to the hospital after he complained of sharp pain in his lower back. An ultrasound revealed tiny stones in his kidneys. The doctor explained that waste materials had crystallised because they were not flushed out properly. He advised his uncle to drink more water to prevent future stone formation.

(a) Name two substances that commonly form crystals in the excretory system.

(b) What happens when these crystals accumulate in the urinary tract?

(c) How can such crystals be removed from the urinary tract?

(d) Is the presence of excess uric acid in urine harmful? Why?

(e) Mention two other body parts where stone formation may occur apart from kidneys.

(a) Two substances that commonly form crystals in the excretory system are calcium oxalate and uric acid.

(b) When these crystals accumulate in the urinary tract, they form kidney stones which may block the flow of urine, causing severe pain, infection and difficulty in urination.

(c) These crystals can be removed by drinking plenty of water to flush them out, by medications, or in severe cases, by medical procedures such as surgery.

(d) Yes, the presence of excess uric acid in urine is harmful because it can crystallise to form stones, which may block urine flow and cause pain and kidney damage if untreated.

(e) Two other body parts where stone formation may occur apart from kidneys are urinary bladder and gall bladder.