Explain where and how urine is produced?
Answers
Answer:
Formation of urine is different in different level of organisations of animal but I will specifically talk about humans .
Explanation:
An organism can be ammonotelic , ureotelic and uricotelic based on the waste product they excrect but talking about mammals we are ureotelic i.e; we secret urea as waste product . Primitive organism like sponges , fresh water fish , aquatic amphibia excret Ammonia as it requires no energy to excret Ammonia but it requires lot's of water to excret Ammonia as it is highly toxic . Later higher organism like us developed a mechanism in which :-
• Urea is produced in liver through ornithine cycle
• Urea is transported by blood plasma and excreted to kidney
• 100 ml of our blood contain 25-30 mg urea
•urea is less toxic than ammonia
• Urine are produced in kidney which contain many other waste products along with urea
• A normal person urine never contains RBC and glucose
• Then it is transported through ureters to the urinary bladder
• urin can be stored for sometimes in urinary bladder
• Human can produce 3x concentrated urin than intial filtrate
• Then urin are excreted out through urethral external opening which can be 20cm long in Human male which carry both urin and semen unlike females and 4 cm long in females . This process of excretion of urin is called micturition