excretion in humans - key terms Flashcards
Define excretion
the removal from organisms of toxic materials, the waste products of metabolism (chemical reactions in cells including respiration) and substances in excess of requirements.
Define the function of a liver
The role of the liver is in the assimilation of amino acids by converting them to proteins.
Define deamination
removal of the nitrogen-containing part of amino acids to form urea.
Define assimilation
uptake and use of nutrients by body cells
Define the function of a kidney
Removal of urea and excess water and the re-absorption of glucose and some salts
Define cortex
contains Bowman’s capsules and coiled tubules
Define ureter
carries urine from the kidney to the bladder
Define medulla
has loops of Henlé and collecting ducts
Define urethra
carrying urine from the bladder to the outside.
Define bladders
stores urine.
Define renal artery
brings wastes and water from the blood
Define renal vein
reabsorbs water and functional molecules and leaves wastes behind
Structure and Function of the Nephron: Define ultrafiltration
blood from the renal artery enters the glomerulus. Water, urea, salts, and glucose are forced into the Bowman’s capsule. Blood cells and large proteins cannot pass through.
Structure and Function of the Nephron: Define selective reabsorption
in the tubule, two-thirds of the salt and water and all the glucose move out of the nephron by active transport. These substances are reabsorbed back into the blood capillary.
Structure and Function of the Nephron: Define loop of henlé
this part is permeable to water but not salt. Water is drawn out of the filtrate in the nephron by osmosis because of the low water potential of the medulla tissue fluid.
