(a)(i) What is excretion? (ii) List the excretory organs in humans and name one waste...
(a)(i) What is excretion?
(ii) List the excretory organs in humans and name one waste product excreted by each organ
(B) Name the excretory organs in:
(i) insects
(ii) earthworms.
Explanation
(a)(i) Excretion: The elimination of waste products; of metabolism; from the body of an organism.
(ii) Excretory organs in Humans with their waste products.
Excretory Organs in humans Waste Products
Kidney - Nitrogenous wastes/urea/water/salts/urine
Skin - Urea/SaltsNVater/Sweat
Liver - Bile/excess cholesterol
Lungs - CO2/water vapour.
(b) Functioning of kidney as excretory:Blood from the renal artery enters the bowman's capsule; through the afferent arteriole; ultra filtration occurs in the Bowman's capsule; high pressure in the glomerulus causes the filtration of small molecules/amino acids/ glucose/ minerals salts/ water/ urea; out of the blood plasma into the cavity of the capsule; the filtrate/glomerular filtrate passes through the nephron; where selective reabsorption of useful metabolites/glucose/amino acids take place; in the descending/first proximal convoluted/coiled tubule; the reabsorption of salts and water is regulated in the loop of Henle; and the ascending/second/distal convoluted tubule/large waste molecules like creatine secreted at loop of Henle; depending on blood concentration; the filtrate continues into the main collecting duct/tube; where further reabsorption of water and salt takes place; the remaining fluid in the duct becomes urine.
(c) Excretory organs in;
(i) Insects → Malpighian tubules
(ii) Earthworm →Nephridia/Nephridium