3. Glomerular filtration and its control.pptx

Question 1

Main processes that occur in the nephron

Answer 1

Step 1: filtration by glomerulus
Step 2: obligatory absorption and secretion and proximal tubule
Step 3: generation of osmotic gradient by loop of Henle
Step 4: regulated absorption and secretion by distal tubule
Step 5: regulation of water uptake by collecting ducts

Question 2

What favours movement into the tubule

Answer 2

Hydrostatic pressure of blood +55mmHg

Oncotic pressure of tubule 0mmHg

Question 3

What opposes movement into the tubule

Answer 3

Hydrostatic pressure of tubule -15mmHg

Oncotic pressure of blood -10mmHg

Question 4

Autoregulation mechanisms of glomerular filtration

Answer 4

Intrinsic or local control”
Myogenic mechanism
Tubuloglomerular feedback

Question 5

What occurs in conditions of high filtrate flow in the tubule

Answer 5

There is an increase in the Na+ and Ca2+ concentrations.
These are monitered by macula densa cells adjacent to the DCT and a signal is sent to the afferent arteriole which causes it to constrict. This lowers flow rate to normal limits.