Excretion Flashcards
Excretion
the removal from organism of the waste products of metabolism (chemical reactions in cells including respiration), toxic materials, and substances in excess of requirements
Egestion
Egestion is the expulsion of undigested food waste
Nitrogenous waste
Formed from excess of proteins and amino acids and forms toxic ammonia
Journey of amino acids
When we eat proteins, digestive enzymes in your stomach, duodenum and ileum break them down to amino acids, which are then absorbed into blood capillaries in the villi in your ileum. which join the hepatic portal vein, which take absorbed food to the liver.
Deamination
the removal of the nitrogen-containing part of amino acids to form urea
Functions of the liver
- Converts excess amino acids into urea and carbohydrates (deamination)
- Synthesizes plasma proteins such as fibrinogen from amino acids
- Controls the amount of glucose in the blood
- Stores carbohydrate as the polysaccharide glycogen
- Makes bile
- Stores Vitamin A, B, D, E and K
- Stores potassium
- Makes cholesterol, needed to repair cells
The kidneys
The kidney has three parts : cortex, medulla and pelvis. leading to the tube is called ureter, which carries urine from kidney to the bladder
Kidney tubules
Kidney is made up of tiny tubules or nephrons. Each tubule begins in the cortex, loops around into the medulla, back into the cortex and goes down the medulla again into the pelvis.
Urine formation
The blood that passes through the kidney is filtered, which removes most of its urea. any glucose is reabsorbed into the blood, along with water and salts. The final liquid produced is called urine (urea and salts) which flows along the ureters’ into the bladder. which them is released by the urthera.
Filtration
Blood is brought into the renal capsule. Small molecules, including water and most of the substances dissolved in it are squeezed. Each one of the thousand renal capillaries has a angle of blood capillaries called glomerulus.
Reabsorption
The fluid in the renal capsule is a solution of glucose, salts and urea, since most of these are needed to the body, all the glucose, some of the water and salt are absorbed to the body.
The bladder
The bladder stores urine, it has stretchy walls, so it can hold quite large quantities, leading out of the bladder is a tube called urethra. The sphincter muscle at the top of the urethra, which is tightly closed. When the bladder is full adults could control its exit from the body, but in young adults, when the bladder is full, the muscle opens up.
Process of dialysis
One needle will slowly remove blood and transfer it to a machine called a dialyser or dialysis machine. The dialysis machine is made up of a series of partially permeable membranes that act as filters and a special liquid called dialyse. The membranes filter waste products from your blood, carried through the tubes by osmosis, which are passed into the dialysate fluid.
A kidney transplant
A kidney transplant is a surgical procedure to place a healthy kidney from a living or deceased donor into a person whose kidneys no longer function properly.
Advantages of dialysis
- One time procedure, once the patient has recovered from the surgery, they would be able to live a normal lifestyle
- less expensive compared to the dialysis carried out throughout the life of a patient.
- kidney transplant provides a higher lifespan than using dialysis.
