B3.3 Flashcards
What 3 things are found in urine?
~ Urea
~ Excess water
~ Excess mineral ions
What produces urea and where?
Excess amino acids are converted into urea in the liver
Where is urea transported to?
From the liver to the kidney via the blood, then stored in the bladder as urine
Why aren’t protein molecules or red blood cells filtered into the kidney tubule?
They’re too big to fit through the partially permeable membrane
What happens in the kidneys?
~ Blood is filtered into kidney tubule
~ All glucose is reabsorbed
~ ions and water needed by the body are reabsorbed
~ Remaining excess ions, excess water and urea are taken to the bladder as urine
What main 3 things do the kidneys do?
~ Control water levels
~ Remove toxic waste
~ Adjust salt levels
What happens if the kidneys don’t work?
Urea and excess ions build up in the body, which can cause illness and death
Why does the dialysis fluid have the same concentration of glucose as the blood?
As this ensures that there will be no diffusion because the blood wants to keep all the glucose it has
Why does the dialysis fluid contain a certain amount of ion concentration?
So that anything that is higher than this in the blood is diffused out
Why is the dialysis fluid always flowing?
To ensure that there is always a low concentration of urea
Why can the body sometimes reject kidney transplants?
Kidneys from other bodies have different tissue types, so the cells have antigens which the body doesn’t recognise and produces antibodies against them
What are advantages of dialysis?
~ More available than kidney donors
~ No drugs needed
What are disadvantages of dialysis?
~ Regular, long sessions
~ Less freedom (can’t go on holidays)
What are disadvantages of kidney transplants?
~ Difficult to find a suitable donor
~ Body may reject kidney
~ Need drugs
What are advantages of kidney transplants?
~ Cheaper than dialysis
~ Freedom
What can happen to cells if the water or ion content of the body is wrong?
The cells will be damaged because osmosis will causes them to shrivel or explode
What does the thermoregulatory centre in the brain do?
~ Has temperature receptors in the brain that detect the temperature of blood in it
~ Has receptors on the skin that send impulses through nerve cells to the thermoregulatory centre which allows it to control temperatures in the body
What happens when you wear shorts in cold weather?
~ Body temperature drops
~ Triggers shivering
~ Produces heat
Why does consuming a cold drink warm you up?
~ Brain temperature decreases, this causes it to stop the body from sweating
~ The lack of sweating causes the skin temperature to increase
What does the pancreas do?
~ Monitors blood sugar levels
~ Produces insulin in ribosomes if blood sugar is too high, and this allows glucose to enter cells
~ Converts glucose to glycogen
What is type 1 diabetes caused by?
Pancreas not producing enough insulin, and this causes the glucose concentration to rise to a high level
What are symptoms of type 1 diabetes?
~ High blood sugar / inability to control blood sugar
~ Frequent urination
~ Thirst
What can cause blood sugar to decrease?
~ Overdose of insulin
~ Not eating or drinking for a while
How do diabetics control their diet?
~ Have small regular meals
~ Have low sugar and carbs
Why is insulin injected and not consumed orally?
~ So it goes straight in the blood
~ It’s a protein so if consumed would be broken down in the stomach
Why does sweating cool the body?
~ Water in the sweat evaporates and carries heat energy away
~ This cools the skin and body
Why does a person look red when they’re hot?
Their blood flows closer to the skin to increase heat lost by radiation
What happens to blood vessels when the body’s too hot?
Blood vessels supplying the skin capillaries dilate so more blood flows through the capillaries, therefore more heat is lost by radiation
What happens to blood vessels when the body’s too cold?
Blood vessels supplying the skin capillaries constrict so less blood flows through the capillaries, therefore less heat is lost by radiation
Why does shivering warm you up?
The contraction of the muscles requires energy, so some heat energy is required
What does insulin do as well as keeping blood sugar levels down?
~ Allows glucose in blood to enter cells and get out of the blood
~ Converts glucose to glycogen which is a way of storing the glucose out of the blood, usually in the liver or muscles
What does the hormone glucagon do?
It’s released from the pancreas and converts glycogen back to glucose (in the liver)
Why does the body cool down by sweating?
As water in the sweat evaporates from skin it carries heat energy away from the skin which cools it and reduces the overall body temperature
What process releases glucose needed to provide energy for the body?
Respiration
What are symptoms of low blood sugar?
~ Weakness
~ Dizziness
What are symptoms of high blood sugar?
~ Thirst
~ Need to urinate
