Urine Production Flashcards
Where does ultrafilteration occur?
Glomerulus and Bowman’s Capsule
Give one component of the blood which is not normally present in the filterate.
Red blood cells
Explain how the cells of the proximal tubule are adapted for thsi function.
There are micro-villi which increase the surface area for faster levels of diffusion. There are lots of mitchondria to produce more ATP (energy).
Describe how ultrafilteration produces glomerular filtrate.
Ulterfilteration occurs in the glomerulus which is surroinded by the boumanns capsule. Blood enters via the afferent arteriole and leaves via the efferent arteriole. It leaves via the efferent arteriole because it has thinner walls which means there is higher pressire for smaller particles like water to move through. Big molecules like red blood cells cannot pass through.
Describe what happens in the loop of henle.
In the asecending loop on the right hand side the Na gets pumped out which requires energy to create a concentration gradient. From the decsdending side water gets pumped into the middle of the loop to create an equilibrium via a process of osmosis. Then, it enters the capillaries and is carried away.
Describe the ascending walls.
These walls are thick and impereable to water.
Describe the descending walls.
These walls are thin and permeable to water.
What does the micro-villi, mitchondria and transport protiens do in the PCT.
Micro-villi helps to increase the surface area for faster diffusion. The mitrochondria provides more ATP which is used as energy. Transport protiens help to transport large molecules like glucose and protiens from the filtrate into the cells.
Why is there a concentration gradient needed?
A concentration gradient is needed for sodium to diffuse into PCT cells. It is established by pumping out Na into the blood.
What does isomotic mean?
The same
Where is there a higher ion concentration?
In the kidney tissue.
Where does water leave?
Via the collecting duck.
Why does water not move out of the ascending loop of henle?
This is because is has to thick walls and it is impermeable to water so it can’t pass through.
What happens to water as it leaves the descending area?
It becomes more concentrated
What does countercurrent multiplication mean?
It maintains the concentration gradient
How does urine move from the collecting duck to the bladder?
It moves through the uretas.
What is the role of the basement membrane of the bowmanns capsule?
It acts as a filter
What is the role of a podocyte?
It makes gaps in the cells
Where does selective reabsorption come from?
In the PCT
What is the first step of osmoregulation?
Receptors in the hypothalamus monitor the water potential of the blood as it flows through the brain.
Second step of osmoregulation?
If the water potential is too low, then the osmorecptor cells lose water bu osmosis and shrink.
Third step of osmoregulation?
This stimulates cells in the hypothalamus to produce ADH.
Fourth step of osmoregulation?
ADH flows through the cells to the pituitary gland, where it is stored until it is needed.
Fifth step of osmoregulation?
ADH is transported to the collecting ducts.
