13.2 Urinary System (Cambridge (CIE) O Level Biology): Flashcards
Exam code: 5090
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- FrontThe Kidney
Define nephron.
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Cards in this collection (23)
Define nephron.
A tiny kidney tubule where the blood is filtered and useful substances are reabsorbed; each kidney contains around a million
Define deamination.
The breakdown of excess amino acids in the liver, in which the nitrogen-containing amino group is removed
Define glomerulus.
A knot of capillaries inside the Bowman's capsule where the blood is filtered
Define assimilation.
When food molecules are converted into other molecules that the body needs
What is the function of the kidneys?
The kidneys filter the blood
Why must excess amino acids be broken down by the liver?
Excess amino acids cannot be stored in the body, so they are broken down by deamination
What is the role of the ureter?
The tube that connects the kidney to the bladder
In which organ does deamination take place?
Deamination takes place in the liver
What is the role of the bladder?
The organ that stores urine after the kidney produces it
What happens to the carbon-containing part of an amino acid after deamination?
It is converted into glycogen and stored
The is the tube that connects the bladder to the exterior of the body.
The urethra is the tube that connects the bladder to the exterior of the body.
Why is the ammonia produced in deamination immediately converted into urea?
Ammonia is highly toxic, so it is converted into urea, which is less toxic
Which four substances are forced out of the blood in the glomerulus to form the filtrate?
The substances forced out are:
glucose
water
urea
salts
How is the urea produced by the liver removed from the body?
Urea dissolves in the blood and is taken to the kidney to be excreted; a small amount is also excreted in sweat
Where in the nephron is glucose reabsorbed into the blood?
Glucose is reabsorbed in the proximal convoluted tubule
In deamination, the nitrogen-containing group is removed from each amino acid.
In deamination, the nitrogen-containing amino group is removed from each amino acid.
When salts are reabsorbed back into the blood in the loop of Henle, water follows by .
When salts are reabsorbed back into the blood in the loop of Henle, water follows by osmosis.
The nitrogen-containing part of the amino acid is turned into ammonia and then into .
The nitrogen-containing part of the amino acid is turned into ammonia and then into urea.
Which three substances make up urine?
Urine is made up of:
urea
water
mineral salts
True or False?
Excess amino acids can be stored in the body for later use.
False.
Excess amino acids cannot be stored, so they are broken down in the liver by deamination
True or False?
Urea is reabsorbed back into the blood as the filtrate passes along the nephron.
False.
Urea is not reabsorbed; it remains in the filtrate and is excreted in the urine
True or False?
Egestion is the removal of the waste products of metabolism from the body.
False.
Egestion is the expulsion of undigested food waste from the anus; excretion is the removal of the waste products of metabolism
True or False?
Each kidney contains around a million nephrons.
True.
Each kidney contains about a million nephrons, which start in the cortex and loop down into the medulla
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