exam 2 material ECG, Nephrology, Respiratory, and Blood

This set of 215 flashcards covers comprehensive topics from a professional medical physiology lecture, including Normal ECG interpretation, introduction to Nephrology, Renal ion regulation, Acid-Base balance, Red Blood Cells, Coagulation, Immunity, and Respiratory Physiology.

Which serum potassium level defines hyperkalemia?

$5.0\,mEq/L$ ($5.0\,mmol/L$) or greater.

What are common ECG changes associated with hyperkalemia?

Peaked T waves, widened QRS, and biphasic QRS-T complexes.

Which drugs can cause hyperkalemia even without kidney dysfunction?

ACE inhibitors, angiotensin-receptor blockers (ARBs), and potassium-sparing diuretics.

What differentiation does measuring plasma potassium help make in hyperkalemia cases?

It differentiates potassium leak from blood cells (clotting, leukocytosis, thrombocytosis) from truly elevated serum potassium.

In which condition should extracellular potassium shift from cells be ruled out?

Acidosis.

List four medications that can decrease potassium excretion.

Spironolactone, NSAIDs, ACE inhibitors, and triamterene.

What clinical conditions can cause a shift of potassium from cells into the ECF?

Metabolic acidosis, insulin deficiency, burns, rhabdomyolysis, and hemolysis.

What does a P wave represent on an ECG?

Depolarization of the right and left atria.

What is the mechanical heart activity corresponding to the P wave?

Atrial contraction.

What does the QRS complex represent?

Right and left ventricular depolarization.

What is the normal duration for a QRS complex?

$0.06 - 0.10\,s$.

A QRS duration greater than which value is considered prolonged?

$0.10\,s$.

What does the T wave represent on an ECG?

Ventricular repolarization.

What is the heart activity associated with the T wave?

Ventricular relaxation.

Define the PR interval.

The time interval from the onset of atrial depolarization (P wave) to the onset of ventricular depolarization (QRS).

What is the normal range for the PR interval?

$0.12 - 0.20\,s$.

A PR interval of less than which value is considered short?

$< 0.12\,s$.

What planes does the ECG record views of the heart in?

Frontal and transverse planes.

Which leads are included in the frontal leads category?

I, II, III, aVR, aVL, and aVF.

Which leads are included in the horizontal plane (precordial) category?

$V_1$ to $V_6$.

How many sensors/electrodes are placed on a patient for a standard 12-lead ECG?

Ten sensors.

Where is electrode $V_1$ placed?

In the fourth intercostal space just to the right of the sternum.

Where is electrode $V_2$ placed?

In the fourth intercostal space just to the left of the sternum.

Where is electrode $V_4$ located?

In the fifth intercostal space in the mid-clavicular line.

Where is lead $V_3$ placed?

Between leads $V_2$ and $V_4$.

Where is lead $V_6$ placed?

Midaxillary line, horizontally even with $V_4$ and $V_5$.

What is the electrical conduction pathway of the heart?

SA node → Internodals → AV node → Bundle of His → R/L bundles → Purkinje fibers.

What enzyme do the kidneys produce to regulate blood pressure?

Renin.

What hormone do the kidneys produce to stimulate red blood cell production?

Erythropoietin.

Urine formation is the result of which three processes?

Glomerular filtration, tubular reabsorption, and tubular secretion.

In which part of the kidney does urine formation primarily take place?

The cortex.

What is the direction of movement during filtration?

From the Glomerulus to Bowman's capsule.

Which process in urine formation is pressure-driven and passive?

Filtration.

What substances are 100% reabsorbed in the proximal tubule normally?

Glucose and amino acids.

What is the primary location for tubular reabsorption?

Proximal tubule.

What is the purpose of tubular secretion?

To remove waste and toxins and control pH.

Which step in urine formation refers to movement from the tubule to the outside of the body?

Excretion.

What is the normal range for blood pH?

$7.35 - 7.45$.

What are the three primary systems that regulate hydrogen ion concentration?

Buffer systems, respiratory regulation, and renal regulation.

Which buffer system is considered the most important in the extracellular fluid?

The bicarbonate buffer system.

Which line of defense against pH change reacts within seconds?

Buffer systems (first line).

What are the three major chemical buffer systems?

Bicarbonate, Phosphate, and Protein buffer systems.

The bicarbonate buffer consists of which two components?

Sodium bicarbonate ($NaHCO_3$) and carbonic acid ($H_2CO_3$).

What is the normal ratio of bicarbonate to carbonic acid?

$20:1$.

Where does the phosphate buffer system primarily regulate pH?

Within the cells and the urine.

Identify the three subsections of the protein buffer system.

Hemoglobin buffer, amino acid (AA) buffer, and plasma protein buffer.

Which organ system achieves the second line of defense for acid-base balance?

Lungs (Respiratory mechanism).

How do the lungs adjust body pH?

By changing the rate and depth of breathing to excrete or retain $CO_2$.

Which acid-base regulatory system provides a permanent solution to disturbances?

Renal mechanism (third line).

What is the normal pH of urine?

$6.0$.

What does the renal mechanism do regarding bicarbonate ions?

It can reserve and produce new bicarbonate ions.

What are the most common causes of hypercalcemia?

Primary hyperparathyroidism and malignancy-associated hypercalcemia.

What serum level defines mild hypercalcemia?

$\ge 10.5\,mg/dL$ ($2.6\,mmol/L$).

What serum level defines severe hypercalcemia?

$\ge 14\,mg/dL$ ($3.5\,mmol/L$).

What is the serum potassium level for hypokalemia?

Less than $3.5\,mEq/L$ ($3.5\,mmol/L$).

What danger can severe hypokalemia induce?

Dangerous arrhythmias and rhabdomyolysis.

What are some causes of renal potassium loss?

Increased aldosterone/cortisol, diuretics (thiazides, loop), and metabolic alkalosis.

How is hyponatremia defined?

Serum sodium concentration less than $135\,mEq/L$.

What is the most common form of hyponatremia?

Dilutional hyponatremia.

What is the first defense against hypernatremia?

Increased thirst and water intake.

Define hypernatremia.

Serum sodium concentration greater than $145\,mEq/L$.

Which electrolyte disorder is classically associated with seizures?

Hyponatremia.

Which electrolyte disorder is associated with 'stones and constipation'?

Hypercalcemia.

What is the major intracellular electrolyte?

Potassium ($K^+$).

What is the primary anion in the Intracellular Fluid (ICF)?

Phosphate.

What component of the kidney concentrates the filtrate and makes the tubule hyperosmotic?

Descending limb of the Loop of Henle.

The ascending limb of the Loop of Henle is permeable to what, but impermeable to what?

Permeable to salt ($Na^+$/$K^+$/$Cl^-$); impermeable to water.

What pump is located in the thick ascending limb?

NKCC (Na+/K+/Cl- pump).

What is the main function of the vasa recta in the countercurrent system?

Acts as the countercurrent exchanger to maintain the medullary gradient.

Which part of the nephron depends on ADH to concentrate final urine?

The collecting duct.

Define metabolic acidosis.

An imbalance caused by excess acid production or decreased acid excretion by the kidneys.

Define respiratory acidosis.

Caused by the accumulation of carbon dioxide ($CO_2$) due to hypoventilation or lung disorders.

What is acidemia defined as?

$pH < 7.35$.

What is alkalemia defined as?

$pH > 7.45$.

What does the mnemonic MUDPILES stand for regarding increased anion gap metabolic acidosis?

Methanol, Uremia, Diabetic ketoacidosis, Propylene glycol, Iron/INH, Lactic acidosis, Ethylene glycol, Salicylates (late).

What does the mnemonic HARDASS stand for regarding normal anion gap acidosis?

Hyperchloremia, Addison disease, Renal tubular acidosis, Diarrhea, Acetazolamide, Spironolactone, Saline infusion.

How is the anion gap calculated?

$Na^+ - (Cl^- + HCO_3^-)$.

What is a normal anion gap value?

$8 - 12\,mEq/L$.

Which disorder is caused by hyperventilation and a $PCO_2 < 36\,mm\,Hg$?

Respiratory alkalosis.

What is the normal value for $PCO_2$ in arterial blood gas analysis?

$35 - 45\,mm\,Hg$.

What is the normal value for bicarbonate ($HCO_3^-$)?

$22 - 26\,mEq/L$.

What is the compensatory response for metabolic alkalosis?

Immediate hypoventilation.

What is the compensatory response for respiratory acidosis?

Delayed increase in renal $HCO_3^-$ reabsorption.

What is the movement of materials across the filtration membrane into Bowman's capsule called?

Filtration.

What process involves moving solutes from the tubule back into the blood?

Reabsorption.

Define tubular secretion.

The movement of solutes from the blood into the tubule filtrate.

What is the osmolarity gradient range from the cortex to the papilla?

From $300\,mOsm/L$ to $1200\,mOsm/L$.

How many liters of blood plasma do the kidneys filter in 24 hours?

$150$ to $180$ liters.

What is the typical daily volume of urine produced?

$1.0$ to $1.8$ liters (average $1.5\,L/day$).

Why does urine develop an ammonia odor if allowed to stand?

Action of bacteria on urine solutes.

What is the normal specific gravity of urine?

$1.001 - 1.035$.

What is the normal glomerular filtration rate (GFR)?

$125\,ml/min$.

What complex catalyzes prothrombin into thrombin?

Prothrombin activator.

What factor initiates the first step of the common pathway?

Activation of factor X.

What does thrombin activate in the common pathway?

Factors V, XI, VIII, and XIII.

What is the stable form of a clot according to the coagulation cascade?

Cross-linked fibrin clot.

Which factor creates the cross-linking process to stabilize the clot?

Factor XIIIa.

What ion is required at multiple steps in the coagulation cascade?

$Ca^{++}$.

What is the intrinsic pathway activated by?

Damaged surface (contact with XII).

What is the extrinsic pathway activated by?

Trauma and Tissue Factor (factor VII).