Excretory System Flashcards
Compare the removal of nitrogenous waste in mammals and birds
Birds- produce urine and faeces combined, remove ammonia as uric acid, uric acid reduces water loss
Mammals- produce urine and faeces separately, remove ammonia as urea, urea is soluble in water
Hormone involved in osmoregulation (Reabsorption or waste)
ADH
Two roles of loop of henle
Selective Reabsorption conducts urine, prevents dehydration
Two functions of the excretory system
Filtering blood, regulating body fluids, removes nitrogenous waste products
3 layers of the kidney
Renal cortex, renal medulla, renal pelvis
Process that occur in the nephron
Ultrafiltration, selective reabsorption, urine formation
Ultrafiltration
Occurs in the bowman’s capsule, removes waste from blood
Selective Reabsorption
Occurs in the loop of henle, decides to reabsorb or excrete water/salt
Descending limb
Permeable to water, water leaves nephron via osmosis, as much water as the body needs is reabsorbed
Ascending limb
Permeable to ions (sodium and chlorine) the concentration of salt decreases (if too much salt) or is reabsorbed if not enough
What happens in the distal convoluted tubule
Final reabsorption of ions, occurs ADH, urine formation
Name the gland the produces ADH
Pituitary gland
Effect of dehydration in the kidney
Water content in blood drops, gland releases more ADH into the blood stream, less water lost in urine, more water absorbed via osmosis, ADH increases the permeability of the collecting duct
Role of the nephron
regulates the concentration of water and soluble substances, by filtering the blood, reabsorbing what is needed and excreting the rest as urine.
Discuss the role of loop of henle in a camel
Recovery of water and sodium chloride from the urine, reduces the amount of water needed for survival, u shaped portion of the tubule that conducts urine, allows the production of urine that or more concentrated than blood
