Excretion CH12 Flashcards
Define Excretion
Excretion is the removal of toxic waste products of metabolism from the body.
Explain why cellulose is not an excretory product
Humans cannot digest cellulose - it goes straight through the alimentary canal, out of the anus into the feaces. Cellulose is not an excretory product. It was never involved in metabolism, it passed through the body unchanged.
What is Egestion?
The passing out of undigested food
What is Nitrogenous waste?
Animals produce nitrogenous waste. This is formed from an excess of proteins and amino acids. The waste product contains Nitrogen.
Explain the process of deamination
Deamination is the removal of the nitrogen containing part of amino acids to form urea. Urea is formed in the liver and removed by the kidneys.
What is the Ureter and the Urethra?
Ureter = Renal Pelvis - bladder
Urethra = Bladder - the outside
Describe the process of Urine formation
As blood passes through the kidneys, it gets filtered. The urea, salt and water is removed. Excess glucose is reabsorbed. The final liquid produced by the kidneys is called urine, It is a mixture of urea and salt dissolved in water. The urine flows out of the kidneys along the ureters into the bladder. The bladder stores the urine and it flows along the urethra when released
what is the renal capsule called?
Glomerulus
What is the affarent arteriole?
The wide artery bringing blood to the glomerulus
What is the efferent arteriole?
The narrow artery taking blood away from the glomerulus
Why can the blood in the glomerulus not get away fast enough?
The blood in the glomerulus cannot get away easily because the artery taking it away is narrow. This leads to there being a high pressure, squeezing the blood in the glomerulus up against the capillary walls
What is too big to be filtered out the glomerulus?
Protein molecules and blood cells are too big to be filtered out the glomerulus
Describe the process of Reabsorbtion.
An useful substances, such as water and glucose are taken back into the blood. The capillaries around each tubule is where the useful substances get absorbed to. By the time the liquid gets to the collecting duct, it has been fully filtered and is now urine. The kidneys are very efficient at reabsorbing water
Describe the bladder and its functions
All urine from the kidneys flows into the ureters which takes the urine to the bladder. The bladder has stretchy walls so it can hold large quantities. Leading out the bladder is the urethra which carries the urine from the bladder to out the body. Adults can control the sphincters around the urethra
Describe Kidney dialysis.
The usual treatment for a person with kidney falier is to have several weeks of dialysis. The persons blood flows out the body and into a machine and back to the body again. Urea diffuses out of the blood and into the dialysis fluid over a semi-permeable membrane. The urea diffuses down a concentration gradient into dialysis fluid.
