Renal Flashcards
What cells make up the PCT?
Simple cuboidal cells with microvilli - tight junctions
What cells make up the loop of Henle?
Flattened Simple Squamous
What cells are found in the DCT?
Principle cells - respond to ADH
Intercalated Cells (I cells) - secrete H+ ions
What are volatile acids?
Acids that can be breathed off - CO2 example.
What are fixed Acids?
Acids that are a result of metabolic processes and cannot be blown off but instead need to be excreted.
What is the 1st concept to be understood in acid base balance?
That the [H+] doesn’t need to be high in order for there to be acid base disturbance. other biochemistry will be affected i.e. HCO3- will be reduced.
How does the Kidney regulate Acid base?
- Re-absorption of HCO3-
- Excretion of Fixed Acid
- In the process of H+ excretion there is new synthesis of HCO3-
During re absorption of HCO3- is there a net loss of H+ or CHO3-?
No there is no net gain or loss. it is equal.
Why is the PCT so good at reabsorbing?
Specialised cellular characteristics:
- large no. of mitochondria
- Brush border for high surface area
- enzymes needed break down of certain substance s
- co-transporters etc.
What cells reabsorb sodium and secrete K+?
Principle cells
Where is K+ and H+ secreted?
DCT and Cortical collecting duct.
Where is most of the Bicarbonate reabsorbed?
PCT - 80-90%
What cell secretes H+ in the presence of aldosterone?
Intercalated cell
Where is the primary place of H+ secretion? What is the flaw in this?
PCT is where the majority of the H ions are secreted however, the majority are reabsorbed.
therefore the PCT does not contribute greatly to hydrogen ion loss.
Why is NH4+ the most important vehicle for H+ excretion?
Because it can be up regulated when needs be
What is the enzyme used to convert glutamine to glutamate?
Glutaminase
How many mosmol are excreted in the urine daily?
600mosmol
What is the minimum urine output in a day?
400mL
600/ 1400 = 400.
1400 refers to 1400mosmol, which is the maximum that the kidneys can concentrate the urine
What is the maximum urine output in a day?
12L
600/50 = 1200
50 refers to the 50mosmol, which is the minimum that kidneys can dilute the urine to.
What are the glucose transporters found in the PCT?
SGLT-2
What is the function of the Mesangial cells?
To remove debris and aggregated proteins from the basement membrane - keeping it clean and well filtered.
Without Aldosterone what will happen to the Na2+ (and therefore water) in the DCT?
It will not be reabsorbed, therefore 10-15% of the filtrate is not reabsorbed back into circulation
What is the creatinine clearance equation?
Volume of urine x Creatinine concentration in Urine
/
Plasma creatinine concentration
What is the effect ADH has at the collecting duct. including aquaporins:
Increases aquaporins II on the lumen side.
Binds to V2 receptors: up regulated cAMP causing microfilaments and microtubles to move vesicles containing aquaporin II to the lumen membrane.
Water then flows in and out through aquaporins III and IV on basal lateral side
What aquaporins are found on the PCT?
Aquaporins I
Level of kidneys?
T12 - L3
What are the adrenals covered by?
Perinephric fat and the renal fascia
*not the renal capsule
nephrone made up of? 3 basic functions of nephron?
renal corpuscle and tubes
Filtration
secretion
absorption
