Renal Pathophysiology Study Guide

What are the three stages of urine formation?

Glomerular filtration, reabsorption, secretion.

What process is involved in glomerular filtration?

A passive process that filters plasma.

What is reabsorption in urine formation?

Substances are reabsorbed from filtrate into blood.

What does secretion entail in the context of the kidneys?

Additional substances are actively secreted into filtrate.

What regulates capillary pressure in the kidneys?

Afferent and efferent arterioles.

What is the normal Glomerular Filtration Rate (GFR)?

Approximately 125 mL/min.

What type of epithelium is present in the glomerulus?

Fenestrated epithelium.

What are podocytes?

Specialized cells in the glomerulus that aid in filtration.

What do mesangial cells do?

Provide support and secrete cytokines in the glomerulus.

What is the role of peritubular capillaries?

Supply oxygen and nutrients to the nephron, responsible for secretion and reabsorption.

Where does 65% of reabsorption occur in the nephron?

In the Proximal Convoluted Tubule (PCT).

What is Tmax in nephrology?

Transport Maximum, the maximum amount of a substance the kidneys can reabsorb.

How does the descending limb of the Loop of Henle function?

It is permeable to water, allowing water to exit the tubule.

What occurs in the ascending limb of the Loop of Henle?

It is impermeable to water and NaCl is actively transported out.

What is the function of the vasa recta?

Helps with water reabsorption via osmotic pull.

What do macula densa cells monitor?

NaCl concentration in the distal tubule.

What do juxtaglomerular cells respond to?

Blood pressure and secrete renin if BP is too low.

What is the effect of renin secretion?

Vasoconstriction of the efferent arteriole increases hydrostatic pressure in the glomerulus.

What nitrogenous waste products are removed by the kidneys?

Urea, uric acid, creatinine.

What hormone does the heart produce that affects kidney function?

Atrial natriuretic peptide (ANP).

What is the role of prostaglandins in the kidneys?

Increase renal blood flow.

What does erythropoietin (EPO) stimulate?

Red blood cell production.

How do the kidneys regulate acid-base balance?

Secreting H+ or HCO₃⁻ based on acidosis or alkalosis.

What does a high Blood Urea Nitrogen (BUN) level indicate?

Potential problems with kidney function.

What is creatinine clearance?

Best indicator of Glomerular Filtration Rate (GFR).

How does aging affect kidney function?

Loss of 10% function per decade after age 40.

What does urinalysis check for?

Specific gravity, glucose, bacteria, WBCs, casts.

What is acute kidney injury (AKI)?

Sudden loss of kidney function occurring within hours or days.

What can cause prerenal AKI?

Reduced blood flow to the kidney, such as dehydration or heart failure.

What is acute tubular necrosis (ATN)?

Common cause of intrarenal AKI due to tubular epithelial necrosis.

What is a common symptom of a urinary tract infection (UTI)?

Burning sensation during urination.

What are the most common pathogens causing UTIs?

E. coli and Staphylococcus saprophyticus.

What are the stages of chronic kidney disease (CKD)?

Stage I: Decreased renal reserve; Stage II-IV: Renal insufficiency; End-Stage Renal Disease (ESRD).

What are risk factors for chronic kidney disease (CKD)?

Diabetes mellitus, hypertension, glomerulonephritis, lupus, polycystic kidney disease.

What happens to surviving nephrons in chronic kidney disease?

Hypertrophy to compensate for loss.

What is metabolic acidosis in CKD?

Decreased HCO₃⁻ reabsorption and increased H+ retention.

What is the preferred treatment for end-stage renal disease (ESRD)?

Kidney transplantation.

What is the role of dialysis in kidney failure?

Removes waste products from the blood.

What risk does uremia present?

Increased risk of pericarditis.