Excretion Flashcards
(14 cards)
Define excretion
Excretion is the removal of waste products from chemical reactions along with excess water and salts
What are two waste products from plants and where are they removed from
Oxygen from photosynthesis
CO2 from respiration
They diffuse out of the stomata
What are the three excretory organs
Kidney, skin and lungs
What are the excretory products of the kidney, skin and lungs
Kidney- urea+salts
Skin- sweat
Lungs-carbon dioxide
Describe the structure of the urinary system
Kidneys, ureters, bladder, urethra
What vein and artery lead to and from the kidney
Renal artery and renal vein
Describe the structure of the nephron
Bowman’s capsule, glomerulus, proximal convoluted tubule, loop or hence, distal convoluted tubule, collecting duct
Define ultrafiltration
Small molecules are forced out of the blood (in the glomerulus) and into the filtrate (in the bowman’s capsule) under high pressure. Large molecules stay in the blood
What is the composition of the glomerular filtrate
Glucose, water, urea, salt (sodium ions)
How is water reabsorbed into the blood
Water is part of the glomerular filtrate during ultrafiltration. As water is a very valuable material The water is reabsorbed via osmosis throughout the tubules in the nephron including the loop of henle and the collecting duct
What is selective reabsorption
The kidney will return some of the small molecules from the filtrate back into the blood
What happens during the selective reabsorption of glucose
Glucose is a very valuable material and must be selectively reabsorbed in the proximal convoluted tubule of the nephron. It is reabsorbed into the capillary network that twist around the nephron. This takes place via active transport using ATP
How does ADH regulate the water content of blood
It causes collecting ducts to become more permeable to water making then leaky so more water is reabsorbed back into the blood
What does urine contain
Water, urea, salt (ions)
