Topic 5 The Kidneys Flashcards
What is the role of the kidneys
Act as filters to clean the blood
How do the kidneys make urine
By taking waste products out of your blood
What is the process filtration in the kidneys
Where substances are filtered out of the blood as it passes through the kidneys
What is selective absorption
When Useful substances such a as glucose, some ions and the right amount of water are absorbed back into the blood
What are the substances removed from the body in urine
Urea
Ions
Water
How urea is made
1) proteins ( and the amino acids that they are broken down into) can’t be stored in the body so any excess amino acids are converted into fats and carbohydrates which can be stored
This occurs in the liver and involves a process called deamination
2) ammonia is a waste product if deamination
3) ammonia is toxic so is converted to urea in the liver
Urea is then transported to the kidneys where it is filtered out of the blood and excreted from the body in urine
How are ions excreted out of the body in urine
1) ions such as sodium are taken into the body by food and absorbed into the blood
2) if the ion (or water) content of the body is wrong the balance between ions and water can be upset meaning too much or too little water is drawn into cells by osmosis
Having the wrong amount of water can damage cells or mean they don’t work as well as normal
3) some ions are lost in sweat but this amount isn’t regulated so fhe right balance of ions must be maintained by the kidneys
The right amount of ions are reabsorbed into the blood after filtration and the rest from the body in urine
How is water removed from the body in urine
1) the body has to constantly balance water coming in against water going out
2) we lose water from skin in sweat and from the lungs when breathing out
3) we can’t control how much we lose in these ways, so the amount of water is balanced by the amount we consume and the amount removed by the kidneys in urine
What hormone controls the concentration of urine
Anti-diuretic hormone (ADH)
Which gland release ADH
Pituitary gland
What does the brain monitor water content of the blood and instruct
Instructs the pituitary gland to release ADH into the bloodstream by the pituitary gland
What is the whole process of water content regulation controlled by
Negative feedback
What does it mean if it’s controlled by negative feedback
If the water content gets too high or too low a mechanism will be triggered that brings it back to normal
What happens if the water concentration is too high
Releases less ADH so less water is reabsorbed from the kidney tubules
What happens if the water content is too low
The pituitary gland releases more ADH so more water is reabsorbed from the kidney tubules
