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70 Cards in this Set
- Front
- Back
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7 essential functions of the kidneys
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1. Regulate serum ion []
2. Regulate serum pH 3. Regulate serum vol. 4. Maintain 300 mOsm 5. Regulate serum mm Hg 6. Endocrine (erythropoetin, calcitrol) 7. Excretion |
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Structural components of kidney
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Review page 1181
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Contents of kidney sinus
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Calyxes, pelvis, fat, vasculature, innervation
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The Cortex contains
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Labryrinth:
-Renal corpuscle, proximal and distal tubules Peritubular capillaries, medullary rays |
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The Medulla contains
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Ray: first part of collecting tubule
Proper: last part of collecting tubule -Loops of Henle, vasa recta |
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Functional unit of the kidney and its subdivisions
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Uriniferous tubule: nephron and collecting duct
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Components of the renal corpuscles
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Bowman's capsule, glomerular capillaries.
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4 parts of a nephron
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Renal corpuscle
Proximal tubule Loop of Henle Distal tubule |
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2 poles of glomerulus
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Urinary (nearest the entrace to the proximal tubule), Vascular (where the afferent and efferent arterioles enter the Bowman's capsule.
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Visceral cells of Bowman's capsule
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Podocytes
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Two types of nephrons and how to distinguish them.
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Cortical and juxtomedullary. Cortical is most common, shortest dip-to-loop, and the corpuscle is high in the cortex (away from the medulla).
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Flow of kidney vasculature
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Renal artery -> segmental arteries -> interlobar arteries -> arcuate arteries -> interlobular arteries -> afferent arterioles -> glomerular caps -> eff. art -> (from cort) peritubular caps OR (from juxta) vasa recta VEINS REVERSE
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What is the countercurrent exchange mechanism?
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The passive exchange of NaCl and H20 between the vasa recta. Descending, it will lose water, ascending, pick it back up.
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Why do kidney arteries infarct?
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The interlobar and arcuate arteries do not anastomose
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What do the endothelial cells of the peritubular capillary make?
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Erythropoetin
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Where are the renal nerves from? What system do they belong to? What is their primary purpose?
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1. Celiac ganglion
2. Sympathetic 3. Vasomotor |
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Direction of tubular reabsorption? Secretion?
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From tubule to capillary, from capillary to tubule
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Is the pressure in the glomerulus high or low?
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High, which facilitates transfer.
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3 pressures in glomerulus
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Capsular hydrostatic promotes filtration, blood colloid and blood hydrostatic oppose
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Epi of parietal layer of Bowman's capsule?
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Simple squamous
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Characteristics of visceral layer of Bowman's capsule?
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Podocytes with primary pedicels that fuse capillaries with basal lamina. **There are slits in between covered with filtration slit diaphragm.
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Golmerular basement membrane
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Fused basal lamina - 1 densa between 2 rara. BLOOD URINE BARRIER
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Flow of filtrate from glomerulus
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1. Through capillary fenestrations between endo -> fused basal lamina -> filtration slit/diaphragm -> Bowman's space
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Contents of lamina rara
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Heparan sulfate (repels anion)
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Contents of lamina densa
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Type IV collage (physical barrier)
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Constitution of the filtration slit diaphragm
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Nephrin (cell adhesion) anchored to actin in pedicel.
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Purpose of mesangial cells
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Physical support of glomerulus, RECEPTORS FOR ANGIOTENSIN II, phagocytosis, fused basal lamina maintenance. They are the housekeepers of the glomerulus.
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Physical ultrastructure of proximal tubule
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Brush-border microvilli, TJ, extensive basal infoldings
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Percentage reabsorptions of proximal tubules
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ALL glucose, amino acids, vitamins, bicarbs. 3/4 of Na, Over half of water.
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What is the structural difference between the thick and the thin portions of Henle's loop?
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Cuboidal/columnar epi become squamous, but the internal diameter is mostly unaltered.
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Is the fluid delivered to the thin limb by the thick hypo, hyper, or isotonic?
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Isotonic, but the total volume is seriously depleted from the original filtrate.
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Characteristic of desc. thin limb of Henle?
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Permeable to H20 which leaves filtrate to interstitium. Salts reenter filtrate. **Urea enters here.
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Characteristic of asc. thin limb of Henle?
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H20 reenters ultrafiltrate, NaCl leave.
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Characteristic of asc. thick limb of Henle
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Impermeable to water, Cl pumps in basolateral membrane ACTIVELY pump Cl into interstitium, Na follow.
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Characteristic of distal tubule
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Macula densa communicates with JG cells in afferent arteriole
**This relationship affects production of renin and aldosterone |
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Effect of ANP on distal convoluted tubule?
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Increased Na excretion
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Effect of aldosterone?
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Remove Na from interstitium, add K
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The loop of Henle does what to the medulliary interstitium? To the ultrafiltrate?
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Makes it hypertonic. Makes it hypotonic.
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Purpose of the intercalcated cells of the the collecting duct?
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Can secrete protons into the filtrate.
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What do the principal cells of the collecting duct do? Under the influence of what hormone?
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They can be made permeable to water under the influence of ADH...allowing us to secrete less H20 (as the water moves into the interstitium). Without ADH stimulation, urine is usually hypotonic.
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The eponym for the collecting duct.
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Duct of Bellini
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Epi covering of the projection of the the medullary pyramid into the minor calyx?
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Transitional
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Summarize the resorption and secretion of urine?
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All key molecules--vitamins, glucose, proteins, and almost ALL the water are resorbed from original filtrate. We secrete ammonia, potassium, protons, creatinine, and drugs.
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What molecule contributes most to medullary interstitial gradient?
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Resorbed urea from the collecting ducts
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Overall, what is the relationship of the kidneys to blood pressure?
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A decrease in pressure -> renin from JG -> cleavage of angiotenogen to angio I, angio II in lungs -> ...aldosterone promotes reuptake of Na and therefore H20 from filtrate in collecting tubules
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6 effects of angio II (some through aldosterone)
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1. Vasoconstrict (aid apparent BP)
2. ADH release 3. Elicits thirst 4. Stim zona glomerulosa to produce aldosterone 5. Stim Na resorption from proximal tubules 6. VIA aldosterone sitm Na resorption from collecting ducts |
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How do the ureters move urine to the bladder? How does urine stay there?
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Peristaltic contractions. There are flaps covering the ureter entrances into the trigone.
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What surface reinforcements are present in the bladder?
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Plaques, or thickening of the luminal plasma membrane. Contains cerebroside. Invaginate when bladder is at rest to maximize needed expansion when full
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The detrusor muscle of the bladder
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L-C-L
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Hormone that works in opposition to aldosterone
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Atrial Natriuretic Peptide
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Hormone that regulates the permeability of the collecting ducts?
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ADH
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Filtration of body capillaries, excepting kidney? Resorption? Lymph flow?
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20 mL. 18 mL. That means about 2-3 mL are part of the lymph system.
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An increase in blood pressure causes (systemic)...
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...increased filtration, resulting in edema
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Sites of high and low arterial pressure in the kidney. Results?
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Glomerular capillaries: high, blood is filtered. Peritubular: low, filtrate is resorbed. This is due to the efferent arteriole separation between the two beds.
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How much urine is secreted in a day?
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1.5 mL
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How is glucose resorbed? Amino acids? Where is the potassium channel?
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Na-dependent transporter. Na-dependent transporter. Lateral membrane.
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Relationship of pressures in a typical capillary? In a capillary bed?
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Initially, hydrostatic pressure will drive filtrate out. The oncotic pressure of large molecules left behind (combined with drop in volume), will draw water back in. In a capillary bed, the relationship is identical, it just may be a different capillary absorbing filtrate from the interstitium.
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Net filtration pressure of glomerular capillary
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+ 9 mm Hg.
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Of the 120 ml/min filtrated into proximal tubule, approx how much is excreted?
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1 ml/min
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What is the nature of blood flow through the renal capillaries?
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Plateau speed. The constant flow rate maximizes the relative filtration/resorption potential of the nephron.
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What enables the resorption of H20 (while everybody else is being pumped in) in the proximal tubule?
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Aquaporins
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Are there aquaporins in Henle's loop? In the distal tubule?
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No. No.
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What drives Cl out of the basolateral membrane of Henle's loop epi?
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K+ is pumped in with Na and Cl across apical membrane -> K simply diffuses back into lumen, but Cl can't follow it. Cl flows out basolateral.
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What ions are pushed through the TJ in Henle's loop?
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Ca and Mg
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What drugs can interrupt absorption in Henle's loop?
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Furosemide (prevents apical absorption of ions), Oubain (prevents Na-K-ATPase from working.)
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The fact that Na is pumped across apical membrane AND basolateral membrane (into cap) in Henle's loop means what?
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Water would like to follow but can't due to lack of aquaporins. Filtrate becomes hypotonic.
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What drugs prevent salt absorption in distal tubule?
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Thiazide.
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What is the role of vasopressin in distal tubule?
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Selective expression of aquaporins, allowing water to follow Na as it is exhanged for K in ultrafiltrate. WILL MAKE Filtrate more hypertonic.
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What drug can block ion absorption in distal tubule?
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Amiloride
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What is the only thing the intercalcated cells of the distal tubule care about?
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Acid-base balance. Typical carbonic anhydrase driven CO2+H20-H2CO3-H + HCO3. HCO3 returns to plasma in exchange for Cl, H is added to
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