B12 Flashcards
What’s the optimum temp for enzymes in the body?
37 degrees C
What does the thermoregulatory centre in the brain contain?
It contains receptors that are sensitive to the temp of the blood flowing through the brain
How does the body measure the core temperature?
Temperature receptor cells in the hypolamus
What do lungs remove?
Lungs remove carbon dioxide, a product of respiration
What does the liver do?
The liver converts excess protein into urea
What does the skin remove?
The skin provides a surface for small amounts of water and salt to move out of the body.
What does the kidney remove?
The kidneys filter the blood, removing urea and excess water and salt, which forms urine. Urine is stored in the bladder before being excreted from the body.
How is urea formed ?
Excess amino acids in the body are broken down by the liver, producing a waste substance called urea
What is deamination?
Deamination is the removal of the amino group from the amino acid forming toxic ammonia, which is then immediatly converted into urea. The urea is then sent to the kidneys
How is urine made?
The kidneys make urine by taking waste products outmof your blood
Explain the process of filtration in the kidneys
Substances are filtered out of the blood as it passes through the kidneys.
Why does carbon dioxide have to be removed from the body? And how is it removed?
Carbon dioxide is produced by the body cells during respiration and it must be removed from the body because dissolved carbon dioxide produces an acidic solution and this would effect the working enzymes in your cells. It diffuses from the blood into the air in the alveoli of your lungs. This air containing the excreted carbon dioxide is removed from your body when you exhale. As a side effect of exhalation, you lose water when the moist air from inside your lungs is forced out of the body.
Why does urea have to be removed from your body? How is it removed?
It has to be removed because urea is poisonous and if levels build up in your body this will cause extensive damage to the cells. It is filtered out your blood by the kidneys and is then passed out the body in the urine produced by the kidneys, along with any excess water and salt
How are water and minerals removed from the body?
Water, mineral ions, and urea are lost from the body in several ways.
Some of these methods give no control over the amount of the various substances lost to the environment.
Control:
-Urea, excess water, and excess mineral ions are removed from the body via the kidneys, then excreted in the urine.
No Control:
-Water leaves the lungs every time you exhale
-Water, mineral ions, and urea are lost through the skin in sweat
What is the function of the kidneys?
Your kidneys are important for homeostasis in the water balance of your body.
If you are short of water, your kidneys conserve it. You produce very little, very concentrated urine and water is saved for use in your body.
If you drink too much water then your kidneys produce lots of dilute urine to get rid of the excess.
The concentration of mineral ions in your body is also important. You take in differing amounts of mineral ions with your food. Some are lost through your skin when you sweat. Your kidneys remove excess mineral ions and excrete them in your urine.
What is selective reabsorption?
Useful substances like glucose, mineral ions and the right amount of water are then absorbed back into the blood.
Proteins cant be stored in the body.
What happens to excess amino acids?
Excess amino acids are converted into fats and carbohydrates, which can be stored
How is the concentration of urine controlled?
The concentration of urine is controlled by a hormone called anti-diuretic hormone (ADH)
The brain monitors the water content of the blood and instructs the pituitary gland to release ADH into the blood according to how much is needed
The whole process of water content regulation is controlled by ….
Negative feedback meaning if the water content gets too high or too low a mechanism will be triggered that brings it back to normal (homeostasis)
What happens if the water content inside the body is too much?
- A receptor in the brain detects that the water content is too high
- The coordination centre in the brain recieves the information and coordinates a response
- The pituitary gland releases less ADH, so less water is reabsorbed from the kidney tubules
What happens if the content of water inside the body is too low?
- A receptor in the brain detects that the water content is too low
- The coordination centre in the brain recieves the information and coordinates a response
- The pituitary gland releases more ADH, so more water is reabsorbed from the kidney tubules
What are some problems that could happen with kidneys?
Kidney stones:
- High salt and minerals in your diet can lead to stones precipitating out
- Extremely painful
- Has to be excreted from the body in the urine
Renal damage / failure:
- The kidney is no longer able to filter blood effective
What is dialysis?
The function of the kidney is carried out artificially
What do dialysis machines do?
In a dialysis machine the person’s blood flows between partially permeable membranes, surrounded by dialysis fluid. It’s permeable to things like ions and waste substances, but not big molecules like protein
What does the dialysis fluid contain?
The dialysis fluid has the same concentration of dissolved ions and glucose as healthy blood.
This means that useful dissolved ions and glucose won’t be lost from the blood during dialysis.
Only waste substances (such as urea) and excess ions and water diffuse across the barrier.
How often do patients have to have dialysis treatment?
They have to have a dialysis session 3 times a week and each session is about 3-4 hours
What are the disadvantages/Advantages of dialysis?
Disadvantages:
- Dialysis may cause blood clots or infections
- Not a pleasant experience and is very expensive to run
Advantages:
- Dialysis can buy a patient with kidney failure valuable time until a organ donor is found
Where are kidneys usually transplanted from?
Healthy kidneys are usually transplanted from people who have died suddenly.
The person who died has to be on the organ donor register or carry a donor card
Kidneys can also be transplanted from people who are still alive ( as we have 2 of them ) but there is a small risk to the person donating the kidney
What are the risks when donating a kidney?
There is also a risk that the donor kidney can be rejected by the patient’s immune system. The patient is treated with drugs to prevent this but it can still happen.
What are the advantages / disadvantages of a kindey transplant?
Advantages:
Transplants are cheaper (in the long run) than dialysis and they can put an end to the hours patients have to spend on dialysis
Disadavntages:
But there are long waiting lists for kidneys
What happens when kidneys don’t work properly? ( why is it a threat to life )
If the kidneys don’t work properly, waste substances build up in the blood and you lose your ability to control the levels of ions and water in your body. Eventually, this results in death.
On what process does dialysis depend on?
Diffusion, down concentration gradient
What does your body do when your too hot ?
1) Sweat is produced by sweat glands and evaporates from the skin. This transfers energy to the environment.
2) The blood vessels supplying the skin dilate so more blow flows closer to the surface of the skin. This is called vasodilation. This helps transfer energy from the skin to the environment.
What does your body do when your too cold ?
1) Hairs stand up to trap and insulating layer of air
2) No sweat is produced
3) Blood vessels supplying skin capillaries constrict to close off the skin’s blood supply. This is called vasoconstriction
4) When your cold you shiver (your muscles contract automatically). This needs respiration which transfers energy to warm the body
