Ganong: Physiology Mcq Pdf

Explanation: Hypotension reduces baroreceptor firing → increased sympathetic outflow to heart (β1 receptors) → increased HR. Vagal tone decreases, not increases.

A) Rapid influx of Na+ through fast voltage-gated channels B) Inward “funny current” (If) carried mainly by Na+ and K+ efflux decrease C) Exclusive T-type Ca2+ channel activation D) Na+/Ca2+ exchanger operating in reverse mode

Explanation: SA node pacemaker activity relies on the hyperpolarization-activated funny current (If) – mixed Na+/K+ inward current, plus decreasing outward K+ current. ganong physiology mcq pdf

A) Increased parasympathetic (vagal) efferent activity to SA node B) Decreased sympathetic efferent activity to the heart C) Increased sympathetic efferent activity to the heart D) Increased atrial natriuretic peptide (ANP) secretion

A) Increased PaCO2, increased pH B) Decreased PaCO2, increased pH C) Decreased PaCO2, decreased pH D) Increased PaCO2, decreased pH A) Increased parasympathetic (vagal) efferent activity to SA

Explanation: Hyperglycemia exceeds renal glucose reabsorption threshold → glucose in tubules → osmotic retention of water → increased urine output.

A) Decreased renin release B) Increased angiotensin II formation C) Decreased aldosterone secretion D) Increased ANP release increased pH B) Decreased PaCO2

Explanation: Hyperventilation → excessive CO2 exhalation → respiratory alkalosis (↓PaCO2, ↑pH).