Kidneys - Module 5 Flashcards
What artery/vein supply the kidney with oxygen?
Renal artery (branched from abdominal aorta) ad Renal vein (filters to inferior vena cava)
Urine is a product produced by kidney tubules
What pathway does this take to exit the body?
Urine passes out of the kidney through ureters where it is held in the bladder and will pass out of the body through the urethra
What are the 3 mains structures of the kidney?
- Cortex
- Medulla
- Pelvis
What is the role of the pelvis?
Central chamber where urine is held before passed onto the ureter
What is the role of the cortex?
Blood filtering occurs so it have a dense capillary network to transfer flood from renal artery to nephrons
What is the role of the Medulla?
The medulla contains tubules of nephrons that for pyramid of kidney and collecting ducts
What are the 5 main structures of the nephrons in the kidney?
- Bownman capsule
- Proximal convoluted tube
- Loop of Henule
- Distal convoluted loop
- Collecting duct
What is the role of the bowman capsule In a nephron?
Contains the glomerulus for ultrafiltration
What is the glomerulus?
Tangle of capillaries
Where is the proximal convoluted tube and what is its role?
Located in the cortex, it is a coiled region of tubule for reabsorption of substances back into the blood
What is the loop of Henule and where is it located?
The loop runs through the medulla and back into the cortex - it creates an environment with high solute concentration
What is the distal convoluted loop?
Second twisted tubule where the fine tuning of body water balance occurs
What do the walls of the distal convoluted loop and the collecting ducts respond to?
ADH hormone changes permeability of walls
What is the collecting duct?
Urine passes through the collecting ducts on its way to the pelvis
What are the 2 filters used in ultra filtration?
- First filter is the BASEMENT MEMBRANE - on the glomerulus and it stops RBC, WBC, and large plasma proteins being removed - there then leave through the efferent arteriole
- Podocytes of bowmans capsule - allows the FILTRATE into the nephron system consisting of glucose, water, Na+ ions, Cl- ions and hormones
What causes a filtration pressure in glomurulus?
Difference in lumen size between afferent arteriole (bigger) and efferent arteriole (smaller)
What does it mean if the loop of henule is longer?
More distance means more time to reabsorption can occur
Where does ultrafiltration occur?
In the glomerulus/bowman’s capsule
What happens in the proximal convoluted tube in selective reabsorption?
All glucose, amino acids and hormones are reabsorbed by active transport
The movement of Na+ ions out of the tube causes a change in water potential meaning water will move out of the tube by osmosis
This in turn causes Cl- ions to diffuse out of the tube
How is the proximal convoluted tube adapted for its function? [2]
- Microvilli to increase surface area
- Lots of mitochondria for active transport
Describe what happens in the loop of Henle in selective reabsorption
In the descending limb water moves OUT by osmosis
- this causes and increase in concentration of Na+ ions and Cl- ions
The bottom of the loop is HYPERTONIC (lots of salt, little water)
In the ascending limb Na+ and Cl- move OUT BY DIFFUSION
And an ISOTONIC point is reached
What happens in the distal convoluted tube during selective reabsorption?
Firstly Na+ will move out by active transport
Secondly water will move out by osmosis using ADH hormone
Finally Cl- ions will move out along electrochemical gradient by diffusion
Here filtrate is only reabsorbed is needed to balance levels in the blood
In selective reabsorption why do substances move by active transport and not diffusion?
If moved by diffusion they may stop diffusing when an equilibrium is reached
Describe the ADH mechanism used in selective reabsorption in the collecting duct
- ADH hormone binds to receptors on cell membrane of collecting duct
- ADH hormone converts ATP to cAMP (secondary messenger)
- CAMP tells vesicles in walls of duct to move and fuse with the inner membrane wall
- Aquaporins in vesicle are now inserted into wall which increase the permeability to water allowing it to move out of the cell wall
What is osmoregulation?
Control of blood, water and salt levels
Where are osmoregulators located?
In the hypothalamus
Where is ADH produced and then stored?
ADH is produced in hypothalamus but stored in the pituitary gland
If blood water levels increase, what are the actions that follow?
Pituitary releases less ADH and the kidney reabsorbs LESS water making urine paler and less concentrated
If blood water levels decrease, what actions follow?
Pituitary releases more ADH and kidney reabsorbs MORE water and urine becomes more concentrated and darker
If someone is diabetic, how would urine indicate this?
More glucose in urine
If someone had muscle damage, how would urine indicate this?
Creating in urine
Describe how monoclonal antibodies are made
- Mouse is injected with hCG hormone
- Mouse produces antibodies for hormone
- B cells that make the hormone are harvested from mouse spleen
- B cells are combined with mylenoma (cancer cell) to form a hybridoma
- Hybridoma rapidly reproduces making lots of cells that produce the antibodies which are collected and purified
How does a pregnancy test work?
- Wick is soaked in urine
- Mobile antibodies with colour pigment will bind to hCG present in urine
- Mobile antibodies move up stick to first window which has a layer of immobile antibodies which will only bind to hCG forming hCG antibody complex as well as a pattern/dye forming a line
- Mobile antibodies continue up wick to second window where any antibodies (with hCG or not) will bind to more immobile antibodies - control line
What are anabolic steroids?
What is used to detect them?
Drug that stimulate muscle growth by mimicking the affect of testosterone and are passed through the urine
Urine is used through gas chromatography and mass spectra
What are 2 indications of kidney failure?
Protein in urine - damage to podocytes on bowman’s capsule allowing plasma proteins into filtration process
Blood in urine - filtration isn’t working correctly
What is polycystic kidney disease?
Where healthy kidney tissue is has fluid filled cysts causing a build up of pressure
When kidneys fail completely, minerals and urea build up
Describe 5 consequences of this occurring
- Loss of osmotic balance in tissues of electrolytes
- Urea buildup poisons cells
- High blood pressure
- Weak bones as calcium and phosphorus balance is lost
- Anaemia as kidneys are involved in hormone production from produce RBCs
What is measured as an indication for kidney disease?
Glomerular filtration rate GFR in cm3/min
To measure this a blood sample is taken measuring creating in the body, if levels rise the kidneys are not functioning properly
Describe haemodialysis
Dialysis that occurs outside the body
1. Blood leaves patient and enters dialysis machine
2. Blood flows between partial permeable dialysis membrane in a counter current system to dialysis fluid
3. Dialysis fluid contains normal blood plasma levels of glucose etc, so none is taken from the blood, but no urea so it is all taken from the blood
Describe peritoneal dialysis
This form of dialysis is done inside the body using peritoneum
The peritoneum is a natural dialysis membrane found in the wall of the abdomen and dialysis fluid is inserted using a catheter
