Excretory System Flashcards
Define excretion:
Excretion can be defined as the removal of the wastes of metabolism from the body
What organs in the body are involved in excretion
Lungs Liver Sweat glands Kidneys alimentary canal
Deanimation
the removal of amino groups from an amino acid molecule
Occurs in liver
A.A + O2 -> carbs + nh3 (ammonia)
Function of Liver
Preparation of materials for excretion* (processes chemical into safer forms -e.g. ammonia into urea)
deanimation
detoxifies alcohol and other drugs
deactivates hormones and converts then into a form that can be excreted by the kidneys
Function of Lungs
excretion of CO2
Function of Sweat Glands
Excretion of sweat in the form of water laced with NaCl, lactic acid and urea.
Function of Kidneys
Main site of excretion
ensures that there is the optimal amount of water in the body
ensures optimal levels of blood pressure
excretes urea, uric acid, toxins, and other wastes
Urinary system consists of:
Kidney Bladder Ureter Urethra (Additionally, aorta, vena cava etc.)
Nephron description
Glomerlus: filters small solutes from blood
Proximal convoluted tubule: reabsorbs ions, water and nutrients; removes toxins and adjusts filtrate pH
descending loop of henle: reabsorbs water through aquaporins
ascending loop of henle: reabsorbs Na and Cl from the filtrate into interstitial fluid
distal convoluted tubule: selectively secretes and reabsobs different ions to maintain blood pH and electrolyte balance
collecting duct: transports to renal pelvis, reabsorbs solutes and water from filtrate
urine output & colour in different conditions
Hot dry day - greater tint of yellow - less. Due to the body needing to use the water more
Cold day - lighter tint of yellow - greater amounts. the body doesnt need to reabsorb all the water as it isn’t working as hard
Pathway of Urine
Urine moves out of nephron - collecting duct- drains into ureter - stored in bladder - bladder stretches until full - urine released from bladder - excreted via urethra
Urine Formation
