The Nephron Flashcards
(31 cards)
What are the 2 parts of the Nephron?
The “Renal Corpuscle” where blood plasma is filtered, and a “Renal Tubule” where the filtered fluid passes through.
What does the “Renal Corpuscle” consist of?
The Glomerulus and Glomerular Capsule.
How does Fluid flow through the “Glomerulus / Glomerular Capsule”?
In order for this to happen the Renal Tubule consist of:
Proximal Convoluted Tubule (PCT), Loop of Helen, Distal Distal Convoluted Tubule (DCT).
Within a Nephron how is PCT and DCT connected?
The Loop of Helen connects these together.
What is the Descending limb of the loop of Helen?
This is the part of the Loop of Helen, where the first part of the Helen dips into the “Renal Medulla”.
What percentage of of Nephrons are “Cortical Nephrons”?
80-85%
What are the percentage of Nephrons that are “Juxtamedullary Nephrons”?
15-20%
What does the “Glomerular Capsule”?
Consist of Visceral and Parietal layers.
What does the Visceral layer of the “Glomerular Capsule” consist of?
Modified Squamous cells epithelial cells called “Podocytes”.
What does an overview of the “Renal Physiology” consist of?
To produce Urine, Nephrons and the collecting ducts perform 3 basic tasks:
Glomerular Filtration, Tubular Reabsorption, and Tubular Secretion.
When producing Urine, what is the “Glomerular Filtration” phase?
Water and most solutes in blood plasma move across the wall of Glomerular capillaries, where they’re filtered and move into Glomerular capsule and then into Renal Tubule.
When producing Urine, what is the “Tubular Reabsorption” phase?
As filtered fluid flows through the Renal tubules and through the collection Ducts, tubule cells reabsorb about 99% of the Filtered water and many useful solutes.
When producing Urine, what is the “Tubular Secretion” phase?
As filtered fluid flows through the Renal tubules and collecting ducts, the renal tubule and duct cell secret other materials, such as waste, drugs and excess ions into the fluid.
What is Net filtration pressure?
Glomerular Filtration depends on 3 main pressures:
1 Pressure promotes filtration, 2 Pressures Oppose Filtration.
What is “Glomerular Blood Hydrostatic Pressure” (GBHP)?
This is the BP in the Glomerular Capillaries.
Promotes filtration by forcing water and solutes in blood plasma through the filtration membrane.
GBHP is about 55 mmHg.
What is “Capsular Hydrostatic pressure” (CHP)?
The Hydrostatic pressure exerted by against the filtration membrane by fluid already in capsular space nd renal tubule.
Opposes filtration and represents a “Back pressure” about 15mmHg.
What is “Blood colloid somatic pressure” (BCOP)?
This is due to the presence of proteins such as albumin, globulins and fibrinogens in blood plasma.
Also opposes filtration.
30 mmHg.
What happens if GFR is too high?
Needed substances may pass too quickly through the Renal Tubules that some are not reabsorbed and are lost in the Urine.
What happens if the GFR is too low?
Nearly all the Filtrate may be reabsorbed and certain waste products may not be adequately secreted.
What are the 2 mechanisms that regulate glomerular filtration?
They operate in 2 main ways:
Adjusting blood flow into and out of the Glomerus.
And by altering the Glomerular Capillary surface area available for filtration.
What are the 3 mechanisms that control GFR?
Renal Autoregulation, Neural Regulation, Hormonal Regulation.
What are the 2 important Outcomes of Tubular Secretion?
The secretion of hydrogen helps control the balance of PH in the blood.
The secretion of other substances help secrete them from the body.
What is the 3rd function of Nephrons and collecting ducts?
Tubular secretion.
What is Tubular Secretion?
The transfer of materials from blood and tubule cells into Glomerular Filtrate.
