Urinary Week 2 Flashcards
What are mesangial cells?
Have properties of immune and smooth muscle cells. They assist filtration barrier, provide structural support, phagocytose foreign material
What is the maximum molecular weight that can pass through the glomerular basement membrane?
68 Da
What type of epithelium is found in the bladder?
Transitional epithelium
What is the series of arteries that supply the kidneys?
Aorta- renal- interlobar- arcuate- interlobulary
What is different about cat kidneys?
Large subcapsular veins runs along surface of kidneys towards the hilum
What substances are reabsorbed from the tubule?
Plasma proteins, glucose, amino acids, hormones, vitamins, salts, electrolytes, water
Where does the majority of reabsorption occur?
Proximal convoluted tubule (65-80%)
What is secondary active transport?
Where primary active transport creates a concentration difference which drives apical Na uptake and other stubatances are aborbed alongside
What is the composition of the ECF?
Nearly all sodium, chloride, little potassium
What is the action of aldosterone?
To reabsorb sodium, acting via the distal tubule on basolateral Na K ATPase and collecting duct via apical ENaC
As sodium is retained, water follows, increasing blood volume
How does aldosterone affect potassium levels?
Potassium is in equilibrium with sodium, so as sodium is retained, potassium will be lost and vice versa
What is the action of atrial natriuretic peptide>
An increase in blood volume means increased stretch of arterial walls and ANP is released from atria. This decreases reabsorption of sodium from tubules and increases excretion to allow blood volume to normalise.
Describe potassium regulation in the distal tubule
Maintained by ROMK small conductance channels and big conductance channels
What is the proportion of the body is made of water?
60%
List the different water compartments
ECF, ICF, ISF, PV, transcellular fluid
What is molality?
Number of moles per kg of solvent
What is oncotic pressure?
The proportion of the total osmotic pressure in plasma exerted by colloids
Explain hypotonic
When the solute potential is higher inside the cell than outside so water moves into the cell down the osmotic gradient
What is an osmole?
The number of ions into which a solute dissociates in solution
What is tonicity?
effective osmolality, equal to the sum of the concentration of the solutes which have the capacity to exert an osmotic force across the membrane
What is the effect of hypertonic cystalline fluid?
ISF expanded, ICV decreased, PV transient expansion
What are juxtamedullary nephrons?
Nephrons positioned deeper in the medulla
What areas of the nephron are permeable to urea?
Proximal tubule, inner medullary portion of collecting duct
How is thirst sensed?
Osmoreceptors in hypothalamus
What is the difference between AQP1 and AQP2?
AQP1 is in apical membrane of PT and descending loop of henle
AQP2 is in collecting duct, ADH responsive
What is the glomerular filtration rate?
Volume of fluid filtered from the glomerular capillaries intot the Bowman’s capsule per unit time
What determines hydrostatis pressure?
Cardiac output, afferent and efferent arterioles, concentration of plasma proteins
What is usually used to mark clearance?
Creatinine
How does the body secrete H+?
Na/H exchange in the proximal tubules, active H+ ATPase pump in the collecting tubules, bound to buffers (phosphate, ammonia)
Where does bicarbonate reabsorption occur?
Mostly in proximal tubule
How does increased PCO2 affect H+ secretion?
It will increase H+ secretion and HCO3 reabsorption
What controls K+ movement into a cell?
Insulin, aldosterone, beta-adrenergic receptors, alkalaemia
What moves K+ across the membrane?
Na+K+ATPase
What term describes excretion of urine by fish?
Ammonotelic
what are granular casts?
Degenerate cellular casts- implies longer stasis
Precipitates protein
Degenerate epithelial cells
