renal 1

A marathon runner collapses in heat after heavy sweating. Which renal hormone helps conserve water?

ADH increases water reabsorption in distal tubule and collecting duct to prevent dehydration

A patient taking NSAIDs develops rising BUN/creatinine. Mechanism?

NSAIDs block prostaglandins → renal vasoconstriction → ↓ GFR

Blood loss after trauma triggers which renal responses?

Sympathetic activation + renin release → vasoconstriction + Na⁺/H₂O retention to restore BP

A patient with low BP but normal osmolarity maintains GFR primarily through which hormone?

Angiotensin II preferentially constricts efferent arteriole to sustain GFR

Older adults on diuretics are prone to orthostatic hypotension because…

Reduced renal concentrating ability and blunted thirst → dehydration and volume loss

What happens to GFR if afferent arteriole constricts?

Glomerular hydrostatic pressure and GFR decrease → reduced filtration

Why does chronic high salt intake raise BP?

↑ ECF volume → ↑ cardiac output → long-term arterial pressure elevation

A client presents with muscle cramps and low plasma sodium after head injury. Likely diagnosis?

SIADH → excessive ADH → water retention → hyponatremia

A patient consumes 1 L of water quickly. What renal changes occur?

↓ ADH → collecting duct becomes impermeable → dilute, high-volume urine

During prolonged fasting, which renal metabolic function becomes important?

Gluconeogenesis from amino acids maintains blood glucose

How do kidneys respond when plasma osmolarity increases?

↑ ADH release and thirst → water retention → normalization of osmolarity

Why do the kidneys have two capillary beds?

Allows sequential filtration (glomerulus) and reabsorption (peritubular/vasa recta) for efficient control of excretion

A patient with renal artery stenosis shows high BP. Which system mediates this?

Renin–angiotensin–aldosterone system activation due to low renal perfusion

In dehydration, urine osmolarity rises to 1200 mOsm/L because…

ADH maximally increases water reabsorption in collecting ducts

What happens to GFR during severe sympathetic activation?

Renal vasoconstriction reduces blood flow and GFR to conserve volume

A PT notices a patient’s BP spikes during resistance training. Which renal mechanism helps counteract chronic increases?

Pressure natriuresis: elevated BP increases Na⁺ and water excretion

A diabetic patient shows glucose in urine. Which tubular process is overwhelmed?

Secondary active transport via SGLT in proximal tubule (transport maximum exceeded)

Why can NSAID use before endurance events be dangerous?

Dehydration + prostaglandin inhibition → renal ischemia and acute injury risk

Which nephron type is most crucial for creating concentrated urine?

Juxtamedullary nephron with long loop of Henle and vasa recta

A patient’s GFR remains stable despite moderate BP fluctuations. Which mechanism explains this?

Renal autoregulation through myogenic and tubuloglomerular feedback