Kidney All Alevels Topic6 Flashcards
What is Osmoregulation?
Where does it occur?
Osmoregulation is the control of the blood water potential.
Occurs in the nephron.
What is the function of the nephron?
Describe the structure of the nephron.
The function if the nephron is the create urine, filter the blood to remove waste and selectively reabsorbed useful substances back into the blood.
Nephrons are long tables surrounded by capillaries
What are the stages in Osmoregulation?
1.Ultrafiltration
2.Selective Reabsorption.
3.Loop of Henle
4.Reabsorption of water at the DCT and Collecting Duct
What is the function of the loop of Henle?
What are the two limbs and the functions of it and describe structure?
Loop of Henle: The Na+ gradient enable Reabsorption of water maintained in medulla by loop of henle.
Ascending Limb:Na+ Activiely transport out. Thicker walls so impermeable to water.
Descending Limb:Walls thinner so permeable to water.
What occurs in the Loop of Henle?
[4STAGES[First 2stages]
1.Mitochondria in walls provides energy to Actively transport Na+ out of Ascending limb of Loop of Henle
2.Accumulation of Na+ OUTSIDE Nephron IN medulla lowers water potential.
What are the last two stages in Loop of Henle?
3.Due to decrease in water potential(lower water potential)water diffuses out by osmosis into interstitial space and then blood capillaries.
4.At base of Ascending Limb some Na+ transported out by diffusion.
What occurs in the last stage of Osmoregulation?
What is the last stage called in Osmoregulation?
Give the first two stages.
The last stage is Reabsorption of water at the DCT and Collecting Duct.
1.Due to all the Na+ actively transported out of PCT, when filtrate reaches top of pct its very dilute.
2.Filtrates moves into Distal Convoluted Tubules and collecting duct.
What is the last thing that occurs in Reabsorption of water at the DCT and Collecting Duct?
When filtrate moves into Distal Convoluted Tubulesand collecting duct.
This section of medulla surrounded two parts of the nephron very concentrated.
So even more water diffuses out of DCT and Collecting Duct.
What remains transported to and forms urine.
What are the adaptions present in Selective Reabsorption?
Microvilli-Large surface area for Reabsorption.
Lots of Mitochondria-Provide energy for Active Transport.
What the first thing that occurs in selective Reabsorption?
1.Concentration of Na+ in PCT decreased as Na+actively transported out of PCT into bloodstream.
What causes Glucose to transported into the blood?
[Last Two stages]
Selective Reabsorption
2.Due to concentration gradient Na+ diffuses down gradient from lumen of PCT into cell-lining the PCT so PCT co-transport Na+ in carry glucose with it.
3.Glucose can then diffuse from Cell-Lining PCT into blood stream.
What is the first stage that occurs in Osmoregulation?
How is Glomerulus formed and what does it cause?
1.Blood enters through Afferent Arteriole which spilts into lots of smaller Cappilaries which make up the Glomerulus this causes a high hydrostatic pressure.
What is and how is Glomerulus Filtrate formed?
Due to the making of Glomerulus causing a high hydrostatic pressure causing water and glucose and amino acids forced out of the capillaries forming Glomerulus Filtrate.
In ultrafiltration what remains in the capillary endothelium?
And where does the blood leave from?
Large proteins and blood cells are too big to leave Capillary endothelium so remain in blood.
Bloods leave via Efferant Arteriole
What is Hypertonic and what is the corrective mechanism for hypertonic?
Hypertonic is blood with too low water potential so lots of ions.
Corrective Mechanism: More water re-absorbed by osmosis into blood from tubules of nephrons so Means urine more concentrated.
