The Kidneys Flashcards
Label this diargam of the urinary system
vena cava
the main vein returning blood to the heart
renal vein
takes “cleaned” blood away from the kidneys
aorta
the main artery supplying oxygenated blood to the body
renal artery
brings blood containing “waste” to the kidneys
urethra
carries urine out of the body
ureter
carries urine to the bladder
bladder
muscular sac that stores urine (about 700cm3)
sphincter muscle
keeps the bladder closed
In diagrams, what colour is deoxygenated blood and what colour is oxygenated blood?
deoxygenated blood = blue
oxygenated blood = red
What are kidneys?
effieienct filtration units
kidneys clean the blood and put it back into the vena cava - waste is removed
What is waste and how is it removed?
waste = CO2, urea
waste is removed in the urine through the ureter
Label this “kidney connections” diagram
Label this “kidney connections” diagram
Label this structure of the kidneys diargam
medulla
lighter middle layer of the kidney
pelvis
central cavity which collects urine
cortex
darker outer layer
nephron
filtration unit (where urine is produced)
about 2cm long and very thin
How is waste removed from the body?
mouth (exhalation)
skin (sweat)
kidneys (urine)
What waste is removed from the body through the mouth (exhalation)?
CO2
water
What waste is removed from the body through the skin (sweat)?
urea
water
salt
What waste is removed from the body through the kidneys (urine)?
urea
water
salt
What is the main function of the kidney?
to get rid of waste such as:
urea
excess water
excess salt (mineral ions)
Is urea present in:
uncleaned blood
urine
cleaned blood
uncleaned blood: yes
urine: yes
cleaned blood: no
Are proteins present in:
uncleaned blood
urine
cleaned blood
uncleaned blood: yes
urine: no
cleaned blood: yes
Are red and white blood cells present in:
uncleaned blood
urine
cleaned blood
uncleaned blood: yes
urine: no
cleaned blood: yes
Is glucose present in:
uncleaned blood
urine
cleaned blood
uncleaned blood: yes
urine: no
cleaned blood: yes
Are amino acids present in:
uncleaned blood
urine
cleaned blood
uncleaned blood: yes
urine: no
cleaned blood: yes
Is salt present in:
uncleaned blood
urine
cleaned blood
uncleaned blood: yes
urine: yes
cleaned blood: a little
Is water present in:
uncleaned blood:
urine:
cleaned blood:
uncleaned blood: yes
urine: yes
cleaned blood: yes
Why is it important to remove urea?
it is toxic
Why is it important to remove excess water?
because of its osmotic effect
Why is it important to remove salt (mineral ions)?
because of its osmotic effect
How does drinking water change urine production?
drinking water —> high water concentration in blood –(kidneys)–> urine volume increases —> blood water concentration drops
How does being thirsty change urine production?
being thirsty —> low water concentration in blood –(kidneys)–> urine volume decreases —> blood water concentration increases
How does eating crisps change urine production?
high solute concentration in blood –(kidneys)–> urine volume decreases —> blood water concentration increases
As … passes through the kidneys, urea is taken out of it and passes into the …. The kidneys also regulate the amount of … and … in the blood and also make sure that the … of the blood is constant.
If you drink a lot of water, it is absorbed from your … into the … and it has an … on the blood. The diluted blood reaches the kidneys which take out … water than usual and pass it into the urine, thereby producing … urine which is more ….
If you eat a lot of … , the solute concentration in your blood …. To counteract this, the kidneys take out … water from the blood and pass it into the urine, therefore producing … urine.
This process of regulation is called ….
As blood passes through the kidneys, urea is taken out of it and passes into the urine. The kidneys also regulate the amount of water and salt in the blood and also make sure that the pH of the blood is constant.
If you drink a lot of water, it is absorbed from your cells into the bloodstream and it has an osmotic on the blood. The diluted blood reaches the kidneys which take out more water than usual and pass it into the urine, thereby producing more urine which is more diluted.
If you eat a lot of salt, the solute concentration in your blood increases. To counteract this, the kidneys take out less water from the blood and pass it into the urine, therefore producing less urine.
This process of regulation is called osmoregulation.
Label this urea production in the liver diagram
Explain what is happening in this diagram
protein, which is found in chicken, is made up of amino acids which are absorbed into the blood
excess amino acids cannot be stored so are first broken down in the liver
then, they are converted into carbohydrates (stored as glycogen) and the waste product urea
urea passes into the blood to be filtered out by kidneys during the formation of urine
CHECK
How does urine composition change when you eat a chicken?
the urine becomes more concentrated because there is more urea
Label this diagram of a the nephron
What are the two steps to urine production in the nephron?
step 1: ultrafiltration
step 2: selective reabsorption
What is ultrafiltration?
filtration at high pressure
Where does ultrafiltration take place?
in the glomerulus and the Bowman’s capsule)
What happens in ultrafiltration?
blood arrives at high pressure in the glomerulus
small molecules are squeezed through pores in the wall of the glomerulus and into the Bowmna’s capsule
large molecules and cells stay in the blood (they are too large to fit through the pores)
reult: filtrate containing small molecules
Where does selective reabsorption take place?
in the proximal convoluted tubule
What happens during selective reabsorption?
useful molecules such as glucose, amino acids and salt are re-absorbed into the blood stream by active transport
some water moves back into the blood by osmosis
urea stays in the filtrate
result: filtrate containing urea
What is needed for active transport?
a carrier protein
ATP energy
a selectively permeable membrane
Why do cells lining the proximal convoluted tubule have lots of mitochondria?
mitochondria respire to provide energy for active transport
Why is urea not reabsorbed?
urea moves from low to high concentration - needs energy
Are the capillary walls more or less permeable than others in the body? Why?
they are much more permeable
the cells of the glomerulus capillaries do not fit together very tightly and there are spaces between them
Describe very briefly what ADH does
it is a hormone produced in the pituatry gland that controls the production of urine
Which substances are present after ultrafiltration in the production of urine?
urea
glucose
amino acids
salt
water
Which substances are present after selective reabsorption in the production of urine?
urea
some salt
water
Which substances are present in te collecting duct in the production of urine?
urea
some salt
water
(check)
Which molecule should we never find in urine. When might you find this molecule in urine?
glucose
if the person is diabetic
The kidneys produce around 180 litres of filtrate in the Bowman’s capsule per day. Only 1.5 litres of the urine produced is lost from the body per day. Why is this?
a lot of the filtrate is reabsorbed
Choose the correct letter to complete the following sentences. Each letter may be used once, more than once, or not at all.
The Bowman’s capsule is in region …
Ultrafiltration occurs in region …
ADH has its effect in region …
Selective reabsorption of glucose occurs in region …
The Bowman’s capsule is in region A
Ultrafiltration occurs in region A
ADH has its effect in region E
Selective reabsorption of glucose occurs in region B
Name three substances contained in normal urine
salts
water
urea
A person cannot make insulin. Explain why this perons’s urine may be different from normal urine
this person’s urine contains glucose
this glucose cannot be converted into glycogen
their cells do not absorb the glucose
Name the parts of the nephron labelled A, B and C
A: Bowman’s capsule
B: Proximal convoluted tubule
C: Collecting duct
Ultrafiltration occurs between the glomerulus and the Bowman’s capsule. Explain what is meant by the term ulrafiltration
the movement of small molecules from the blood into the kidney under pressure
Which part of the kidney nephron is used to reabsorb the filtered glucose?
the proximal convoluted tubule
Where are water levels regulated in the kidneys?
CHECK
What does ADH do to the collective duct?
makes the collective duct more permeable to water so that more water is reabsorbed back into the blood when we are thirsty
Give a summary of water homeostatis when we are thirsty
ADH secreted
collecting ducts become more permeable to water
more water is reabsorbed into the bloodstream
less urine is produced
Give a summary of water homeostatis when drink water
less ADH secreted
collecting ducts become less permeable to water
less water is reabsorbed into the bloodstream
more urine is produced
Complete the detailed water homeostatis flow diagram for being thirsty:
stimulus
receptor
integrator (set point)
effector
response
stimulus: low water (high solute) concentration in the blood
receptor: osmo-receptors in the hypothalamus
integrator (set point): hypothalamus stimulates pituitary gland to release ADH (anti diuretic hormone)
effector: ADH works on collecting ducts which become more permeable to water
response: more water is reabsorbed into the blood; less urine is produced
Complete the detailed water homeostatis flow diagram for being thirsty:
stimulus
receptor
integrator (set point)
effector
response
negative feed back loop???
??
Complete the detailed water homeostatis flow diagram for drinking water:
stimulus
receptor
integrator (set point)
effector
response
stimulus: high water (low solute) concentration in the blood
receptor: osmo-receptors in the hypothalamus
integrator (set point): hypothalamus does not stimulate pituitary gland to release ADH (anti diuretic hormone)
effector: collecting ducts are less permeable to water
response: less water is reabsorbed into the blood; more urine is produced
Complete the detailed water homeostatis flow diagram for drinking water:
stimulus
receptor
integrator (set point)
effector
response
negative feed back loop??
As a result of exercise on a hot day, there ate changes in the volume and concentration of urine. Describe these changes in urine and explain how these changes are brought about
Because it is a hot day, water is lost through sweat so the water concentration in the blood is low
This is detected by the osmo-recpetors in the hypothalamus which stimulates the pituitary gland to release ADH
ADH works on the collecting ducts which become more permeable to water
In response, more water is reabsorbed into the blood and less urine is produced
Less water is in the urine
Some substances affect the secretion of ADH. These substances increase the production of urine and are known as diuretics. Suggest how diuretics increase the production of urine
Some substances, such as water, excrete less ADH from the pituitary gland so the collecting ducts become less permeable to water and less water is reabsorbed into the bloodstream
As a reult, more urine is produced
Describe how antiduiretic hormone (ADH) regulates the water content of the blood in cyclists
The water content of the blood decreases and so more ADH is released
The collecting duct becomes more permeable to water and more water is reabsorbed into the blood
As a result, less water is lost from the body/more concentrated urine is produced
What is meant by homeostatis
the regulation of conditions inside the body despite external changes
Name the organ that normally produces ADH
the pituitary gland
How does ADH get from the pituitary gland to the kidney?
via the blood
Name the part of the kidney nephron that repsonds to ADH
the collecting duct
Explain why lack of ADH is a problem
less water is reabsorbed into the blood/ the blood becomes more concentrated
the person becomes dehydrated/ loses too much water
Suggest what people with diabetes, who do not produce enough of the hormone ADH, must do in order to survive
drink lots of water
ADH tablets/injections
Why is kidney failure a threat to life?
you would have unclean, toxic blood filled with urea
you would lose too much water
What can cause kidney failure?
kidney infections
damaged nephrons
physical activities
What should people with kidney problems eat?
less protein
less salt
How can kidney failure be treated?
a kidney transpant
dialysis
What does dialysis do?
it carries out the same function as the kidney
Label this diagram of the set-up of a dialysis machine
What is the function of the pump in the dialysis of machine?
it keeps blood moving through the dialysis machine
In which direction is blood pumped in the dialysis machine?
clock-wise (vein to the artery)
Which direction does the fluid go in the dialysis machine?
against the direction of the blood
Why is blood taken from a vein in the dialysis machine?
the pressure is lower than from the artery
Why is a blood thinner used in the dialysis machine?
the blood could otherwise clot
Why is a warm water bath used in the dialysis machine?
it has to be body temperature (37oC) otherwise the red blood cells could be damaged
the warm water bath = 37oC
What is the system in the dialysis machine? Is the concentration gradient high or low?
a counter-current system
high concentration gradient
The dialysis membrane is …
The dialysis membrane is selectively permeable
What is the mechanism of dialysis?
uncleaned blood enters the dialysis machine and flows between the dialysis membranes
dialysis fluid contains salt, glucose, amino acid and water in normal blood concentration but not urea
urea, excess salt and water diffuse from the blood through selectively-permeable membrane into the dialysis fluid
dialysis fluid containing urea is excreted as waste while cleaned blood leaves the dialysis macihne and travels back to artery
What is in dialysis fluid that makes it work?
every solute in blood except urea
urea is at a high concentration in blood so it would move
What is removed from the blood in dialysis?
urea
excess salt
excess water
What processes in the dialysis machine are incolved?
diffusion
osmosis
Why don’t red blood cells and proteins diffuse out of the blood?
they are too big to get through the pores of the dialysis membranes
What makes the dialysis process efficient and quick?
high surface area
high concentration gradient
What is the result of dialysis compared with the kidneys?
the result is the same
waste (urea, excess salts and water are removed)
How are the mechanisms used in kidneys different to dialysis?
kidneys: ultrafiltration, selective reabsorption, (active transport and osmosis)
dialysis: diffusion and osmosis
How long does a dialysis session last?
5 hours
How often does dialysis need to happen?
every 3 days
What are the dietary restrictions of living with dialysis?
no protein
no salt
the amount of fluid which may be taken is very restricted, as the body has no way of getting rid of it
What is the mechanism of a kidney transplant?
the patient (recipient) receives a single kidney from a donor
the donor kidney is placed in the abdomen and attached to the blood vessels and the ureter
What are the problems of kidney transplants? How can these problems be overcome?
cuts into a major artery - can loose a lot of blood
your body could reject the transplant - give the patient immunosuppressive drugs
Compare dialysis to a kidney transplant:
sessions
dialysis: regular dialysis sessions (2-3 times a week, life-long)
transplant: no dialysis sessions
Compare dialysis to a kidney transplant:
diet
dialysis: restrictions in what you eat and drink
transplant: can eat and drink normally
Compare dialysis to a kidney transplant:
cost
dialysis: expensive long-term
transplant: one-off expense of surgery
Compare dialysis to a kidney transplant:
availability
dialysis: more readily available
transplant: requires a suitable organ donor (tissue match)
Compare dialysis to a kidney transplant:
longevity
dialysis: can be done over many years
transplant: do not last for life (new transplant needed every 10 years)
Compare dialysis to a kidney transplant:
dangers
dialysis: no danger of rejection, no need to take immunosuppressive drugs
transplant: danger of rejection, need to take immunosuppressive drugs (risk of infection)
