B3 - Keeping Internal Conditions Constant Flashcards
Give three factors that the body has to control.
- Core body temperature.
- Water and ion balance.
- Blood sugar levels.
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What are the two main waste products produced in the body?
- Carbon dioxide
- Urea
How is carbon dioxide produced in the body?
Through respiration.
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Why is it important to remove carbon dioxide from the body?
CO2 dissolves to produce carbonic acid in the blood.
What happens if carbon dioxide isn’t removed from the body?
Enzymes don’t work as efficiently since the pH level would change.
What percentage of CO2 is expended from the body?
4%
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How is urea produced?
- Excess protein is broken down into amino acids.
- The amino acids are broken down to produce carbohydrates and ammonia.
- The liver converts the ammonia into urea.
What happens to the rest of the amino acid molecule when it has gone through the liver?
-It is used for respiration or creating other molecules.
Give three ways in which water is lost.
- Breathing
- Sweating
- In urine
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Give two ways in which ions are lost.
- Sweating
- In urine
What is homeostasis?
The maintenance of constant internal body conditions.
Give three functions which the kidney undertakes.
- Filtering out urea from the blood.
- Removing excess water.
- Removing excess ions.
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Where is urine stored?
The bladder.
What happens to the water passing through the kidneys if the body has very little water?
The water is conserved.
What happens to the water passing through the kidneys if the body has a lot of water?
Lots of urine is produced to get rid of the excess.
What is left in the blood when passing the kidney tubules?
- Blood cells
- Large molecules
- Proteins
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Why can’t some molecules diffuse across into the kidney tubules?
They are too big to pass through the membrane of the tubule.
How are mineral ions, water and sugars conserved?
They are reabsorbed by the kidneys.
How are sugars reabsorbed?
Active transport
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How much sugar is conserved by the kidneys?
All of it.
What is selective re-absorption?
The control of the amount of water reabsorbed by the kidneys.
What make urine yellow?
Urobilins
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What are urobilins?
Yellow pigments
How are urobilins produced?
The breakdown of haemoglobin in the liver.
What are the vein and artery leading to the kidneys called?
The renal vein and artery.
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Where is the dirty blood filtered in the kidney?
A glomerulus.
What is a glomerulus?
A capillary network.
Why is pressure built up in a glomerulus?
To filter most of the liquid.
How is high blood pressure built up in a glomerulus?
The vein has a smaller lumen than the artery.
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Where are useful substances reabsorbed in the kidney?
A nephron.
When is dialysis needed?
When a person’s kidney(s) fail.
What are the two most effective ways of treating kidney failure?
- Dialysis
- Kidney transplant
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What does dialysis fluid contain?
The same concentration of useful substances as the blood.
How long does dialysis take?
Eight hours
Why does dialysis fluid have the same concentration of glucose and mineral ions as the blood?
So there is no net movement.
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Describe the process of dialysis.
- Blood is pumped out of the artery and thinned to prevent clotting.
- The blood passes through the dialysis machine where it is cleaned.
- The clean blood flows through a bubble trap and enters the vein.
Why doesn’t dialysis fluid contain any urea?
To make a steep concentration gradient.
Why is blood passed through at a counter current to the dialysis fluid?
To maintain a steep concentration gradient.
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Give three disadvantages of dialysis.
- The patient has to follow a controlled diet.
- The dialysis process takes a long time.
- The balance of substances in the blood can become difficult to control over time.
What is the main problem with kidney transplants?
Rejection.
Give two ways chance of rejection of a transplant is reduced.
- The match between antigens is made as close as possible.
- The recipient is given immunosuppressant drugs.
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Give two advantages of a kidney transplant.
- There are no restrictions.
- The patient can have a varied diet.
Give three disadvantages of a kidney transplant.
- There is a risk of rejection.
- Patients need regular check-ups.
- The chance of getting a transplant is low.
Give three things that can affect internal body temperature.
- Energy produced in the muscles during exercise.
- Fever caused by disease.
- External temperature rising or falling.
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What controls the core body temperature?
The thermoregulatory centre of the brain.
What happens when the body gets too hot?
- The blood vessels that supply the skin capillaries dilate.
- The rate of sweating increases.
- The hairs lie flat.
How does dilating the blood vessels cool the body?
The skin has more blood flowing near so more energy is lost by radiation.
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How does sweating cool the body?
The sweat cools the body as it evaporates.
What happens when the body gets too cold?
- The blood vessels supplying the skin constrict.
- Sweat production is reduced.
- Shivering.
- The hairs stand up to trap air.
What is the cost saving to the NHS of kidney transplants?
£512 million a year
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What is hypothermia?
The core body temperature falling below 35C.
Give three symptoms of hypothermia.
- Extreme tiredness
- Not wanting to move
- Blue lips
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What controls and monitors the blood glucose level?
The pancreas.
What is glucose?
A sugar
What is glycogen?
A storage carbohydrate found in the liver and muscles.
What is glucagon?
A hormone that increases blood glucose concentration.
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What is insulin?
A hormone that allows glucose to move from the blood into the cells.
Why is glucose converted into glycogen?
- To prevent water from diffusing into the higher concentrated solution.
- Glycogen is insoluble so doesn’t affect water movement.
What is type 1 diabetes?
When the pancreas doesn’t make enough insulin.
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What used to be used to treat diabetes?
Insulin from pigs and cows.
How is insulin produced nowadays?
Genetically engineered bacteria.
How have embryonic stem cells been used to cure type 1 diabetes?
Turning stem cells into insulin secreting cells.
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What are the three ways that people can control type 2 diabetes?
- Eating a balanced diet.
- Losing weight.
- Doing regular exercise.
What three types of drugs are used to treat type 2 diabetes?
- Help insulin work better in cells.
- Help the pancreas produce more insulin.
- Reduce the amount of glucose absorbed in the gut.
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