15.5 The Structure And Function Of The Mammalian Kidney Flashcards
Which part of the body is the kidney attached to?
Back of abdominal cavity
What two things are the kidneys involved in?
Excretion and osmoregulation
What are the two purposes of the kidneys?
Filter out nitrogenous waste products (like urea) from the blood
Helps maintain water balance and pH of blood and therefore tissue fluid around cells
Can you recall how blood enters and flows through the kidneys?
- Renal arteries branching off from the abdominal aorta supply the kidneys with blood at arterial pressure
- Blood that circulated through kidneys is removed by renal vein
- Renal vein drains into inferior vena cava
How much blood passes through the kidneys every minute?
90-120cm3 per minute
How long does it take for all the blood in the body to pass through the kidneys once?
1 hour
How much blood does the kidneys filter in a day?
180dm3 every day
How much urine is produced in a day?
1-2dm3
What are the kidneys made up of?
Millions of nephrons
What are nephrons?
Small structures that act as filtering units
What is the strike liquid produced by the kidneys called?
Urine
What are ureters?
Tubes leading out of the kidney
What is the bladder?
Muscular sac that stores urine
Where does the urine collect?
Bladder
How much urine can the bladder store?
400-600cm3
What are the 3 main parts of the kidney?
Cortex, medulla, pelvis
What is the cortex?
Filtering of blood takes place
Very dense capillary network carrying blood from renal artery to nephrons
Dark outer layer
What is the medulla?
Contains tubules of nephrons forming kidney pyramids and collecting ducts
Lighter colour
What does ‘pelvis’ mean in Latin?
Basin
What is the pelvis?
Central chamber where urine collects before passing down ureter
How long is each nephron?
3cm
How many nephrons are in EACH kidney?
1.5 million
What is the Bowman’s capsule?
Cup-shaped structure containing glomerulus
What is the glomerulus
Tangle of capillaries
More blood enters than leaves it due to ultrafiltration processes taking place
What is the proximal convoluted tubule?
First coiled region of tubule after Bowman’s capsule
Found in cortex
Where many of the substances needed by body are reabsorbed into the blood
What is the loop of Henle?
Long loop of tubule creating region with very high SOLUTE concentration in tissue fluid deep in the kidney medulla
Contains descending limb, ascending limb and hairpin bend
Can you describe how the loop of Henle looks like?
Descending limb runs from cortex -> through medulla -> hairpin bend at bottom of loop
Ascending limb travels BACK UP through medulla to cortex
What is the distal convoluted tubule?
Second twisted tubule where fine-tuning of water balance of the body occurs
ADH has effect on walls
Further regulation of ion balance and blood pH takes place
What is the collecting duct?
More fine-tuning of water balance takes place
Walls are also sensitive to ADH
Urine passes down collecting duct through the medulla to pelvis
What does the nephron have around it?
A network of capillaries that lead into a venule and then to renal vein
Can you briefly explain the solute concentrations of the blood leaving the kidney?
Greatly reduced levels of urea
Levels of glucose and amino acids almost the same
E.g. some blood is used for SELECTIVE REABSORPTION
Mineral ion concentration restored to ideal levels
