The Kidneys Flashcards
How large are kidneys
7-12cm length
200-400g = 0.5% body mass
Where are the kidneys
Below lungs
Behind stomach
Towards back
What do kidneys do
Production of urine absorbing nutrients we dont want to excrete
Label urinary system
Label kidney
Function of: vena cava
Main vein returning blood to the heart
Function of: renal vein
Takes ‘cleaned’ blood away from kidneys
Function of: aorta
Main artery supplying oxygenated blood to body
Function of: renal artery
Brings blood containing ‘waste’ to the kidneys
Function of: urethra
Carries urine from bladder to exterior
Function of: ureters
Carry urine to the bladder from the kidneys
Function of: bladder
Muscular sac that stores urine (~700cm(cb))
Function of: sphincter muscle
Keeps bladder closed
Function of: medulla
Lighter middle layer of kidney
Function of: pelvis
Central cavity which collects urine
Function of: cortex
Darker outer layer
Function of: nephron
Filtration unit (where urine is produced)
Kidneys excrete the same waste products as sweat just in different quantities and proportions
Urea
Minerals (ions/salt)
Water
The main function of the kidney is to get rid of … Such a … Extra … And extra …
Waste
Urea
Water
Salt
Dirty blood has urea, proteins, calls, glucose, amino acids, salt and water
But clean blood has
Everything but urea and only some salt and water after leaving the kidney
A person should only excrete through urine:
Urea, some salt and some water, however diabetics would excrete glucose
Effects on urine composition when drinking water
Blood volume increases
Goes through kidneys
Urine volume increases
Blood volume decreases
Effects on urine composition when thirsty
Blood volume decreases
Goes through kidneys
Urine volume decrease
Blood volume is maintained
Effects on urine composition when eating salt (crips)
Blood solute concentration increases
Goes through kidneys
Urine volume decreases
Water kept in blood
Why do we need to excrete urea
As it is a waste product from our blood with no nutrients
Ammonia and urea is a toxic build up
Why does the amount of water in a cell need to be regulated
Water and salt levels need to remain the same as cells cannot work properly for chemical reactions to occur (too little water) and not efficient enough (too much water)
AKA osmoregulation
Step 1: ultrafiltration
Bowman’s capsule and glomerulus
- small molecules are filtered out of the blood
- large molecules stay in the blood
- high pressure of blood
- gaps in the walls of the glomerulus and Bowman’s capsule
Step 2: selective reabsorption
Proximal convoluted tubule and blood stream
- useful molecules are re-absorbed back into the bloodstream by active transport
- some water moves back into blood by osmosis
- urea stays in the filtrate
Step 3: adjusting salt concentration
Loop of Henlé
-by taking or adding more salt to change blood salt concentration
Step 4: adjusting the PH, salt and water concentration
Distal convoluted tubule
FINISH THIS
Step 5: adjusting water concentration
Collecting duct
FINISH THIS
Variable for negative feedback would be
Low/high water concentration in blood
Negative feedback for low water concentration in blood Ie Stimulus Receptor/sensor Integrator/control centre Effector Response Negative feedback
- low water concentration in blood (high solute)
- osmo-receptors in hypothalamus
- hypothalamus stimulates pituitary gland to release ADH/thirst centre in hypothalamus
- ADH works on collecting ducts which become more permeable to water/drinking
- more water reabsorbed into blood thus less urine is produced/water concentration in blood increases
- as water concentration increases –> ADH secretion stops
Negative feedback when high water concentration in blood
- high water concentration in blood (low solute)
- osmo receptors in hypothalamus
- hypothalamus does not stimulate pituitary gland to release ADH
- collecting ducts become less permeable to water
- less water is reabsorbed into blood, more urine is produced
- water concentration decreases
Why does the body need amino acids
To be taken into the bloodstream via the ileum and transported into cells that need to build new proteins
What happens to the protein we eat in the digestive system
Broken down into amino acids with help from pepsin and trypsin (enzymes) in the stomach and small intestine respectively
What happens to the excess amino acids in the blood that the body does not need
Broken down or destroyed
The first thing the liver does with excess amino acids is to deaminate them. What molecules are formed as a result of this
Ammonia
Ketoacid
Called deamination
Why does ammonia have to be turned into urea
As ammonia is very poisonous and urea is less toxic
Where does the urea go after it has been made in the liver
Carried from the liver by blood in hepatic vein to heart to lungs and back to heart, leaves heart by aorta and enters kidneys via renal artery which gets rid of it through urine via ureters temporarily stored in bladder and leaves body by urethra
What happens to useful amino acids
Taken up by body cells and used to build new proteins
Function of: glomerulus
Network of capillaries in Bowman’s capsule
Function of: Bowman’s capsule
Where filtrate is kept
Function of: ultrafiltration
Small molecules filtered out of blood, large molecules stay in it
Function of: proximal convoluted tubule
Where selective reabsorption takes place
Function of: selective reabsorption
Useful molecules reabsorbed back into bloodstream by active transport, water by osmosis
Function of: loop of Henlé
Adjusting salt concentration
Steak to urine:
1) the steak is eaten and enters the …
2) protein in the steak is broken down into … With the help of the enzymes … And … This happens in the … And … Respectively
3) amino acids are absorbed into the … In the small intestine (ileum)
4) useful amino acids are taken up by body cells and used to build new …
5) … Amino acids are transported to the liver
6) in the liver, excess amino acids are broken down into … + …
7) ammonia is converted into …
8) urea leaves the liver in the hepatic vein and travels to the … (And from there to the lungs and back to the heart)
9) urea leaves heart in the … And enters the … Via the renal …
10) urea us filtered out if the blood in the … Into urine
11) urine leaves the kidney via the … Is temporarily stored in the … And leaves the body via the …
Digestive system Amino acids Pepsin Trypsin Stomach Small intestine Bloodstream Cells Proteins Excess Liver Excess Ammonia Keto acid Urea Heart Aorta Kidneys Artery Kidney Ureters Bladder Urethra
Why is kidney failure a threat to life
- build up of urea in the body (toxic)
- water and salt not balanced which can lead to osmotic problems
What can cause kidney failure
- infectious diseases
- tumours
- accidents
- diabetes
How can kidney failure be treated
Dialysis or kidney transplant
What should people with kidney problems eat
Less protein
Monitor water and sugar levels
Principle of dialysis is the same as a kidney
Dirty blood
Dialysis machine
Clean blood + waste
Be able to label a dialysis machine
Copy from biology folder
1) dialysis fluid contains:
2) … blood enters the dialysis machine
3) urea + excess salt + excess water diffuse through … Membrane into dialysis fluid
4) dialysis fluid containing urea is … As waste while clean blood leaves the dialysis machine and … To the body
1) no urea, salt, amino acids, glucose + water in normal blood concentration
2) dirty
3) a semi - permeable
4) discarded, travels back
A patient with kidney failure will soon die unless there is a way to rid the body of the … And excess … A dialysis machine provides … Kidney for the sufferers of kidney failure
Urea
Salt
An artificial
… Is drawn from a vein in the body and enters the dialysis machine. The blood flows through a dialysis … Which is … It has in it pores which will allow small particles to pass through, like …, …, …, …, and amino acids but not large particles like … Or …
Blood Membrane Semi-permeable Salt Water Urea Glucose Proteins Blood cells
Surrounding the membrane is … This contains useful molecules which should be in the blood plasma (eg …, … And some salt), in the correct concentrations. There is no … In the dialysis fluid.
Dialysis fluid
Glucose
Amino acids
Urea
The urea moves from the blood to the dialysis fluid by … There is no … Diffusion of glucose and amino acids from the blood to the dialysis fluid.
Diffusion
Net
Excess … Diffuses out of the … Keeping it at the right levels. Osmoregulation occurs in much the same way. If there is too … Water in the blood it will enter the dialysis fluid by … The reverse occurs if the blood is too … The blood us kept at the correct … While it passes through the machine. The blood then returns to the body.
Salt Blood Much Osmosis Concentrated Temperature
A dialysis patient needs to be careful what they … And … Too much … And protein between dialysis treatments can cause problems. Also the amount of … Which may be taken is very restricted as the body has mo way of getting rid of it.
eat Drink Salt Protein Water
Disadvantages of dialysis
- regular sessions (2/3 times a week)
- can be from 4-10 hours
- restrictions in food and drink
- expensive long term
Advantages in dialysis
- more readily available
- can be done over many years
- no danger of rejection
- no need to take immunosuppressive drugs
Advantages for transplant
- no dialysis sessions
- can eat and drink normally and lead normal life
- after surgery, relatively low cost
Disadvantages for transplant
- requires suitable organ donor (tissue match)
- transplants don’t last for life (new transplant needed every 10 years)
- danger of rejection (regular check-ups needed)
- need to take immunosuppressive drugs therefore risk of recurrent infection
