Discover how different parts of the nephron contribute to urine formation and how osmolarity changes throughout. Learn how countercurrent mechanisms create and preserve the medullary concentration gradient.

Review the major functions of the urinary system, including waste excretion, fluid and electrolyte balance, and blood pressure regulation. Understand the differences between plasma, filtrate, and urine, and the processes of filtration, reabsorption, secretion, and excretion.

Explore how hydrostatic and oncotic pressures regulate capillary exchange. Learn how net filtration pressure (NFP) drives fluid in or out of capillaries and how the lymphatic system prevents edema by returning excess fluid to circulation.

Understand how local control mechanisms adjust blood flow to match tissue demand. Explore metabolic and myogenic responses, precapillary sphincters, and the balance between vasodilation and vasoconstriction in maintaining perfusion.

Learn how central and peripheral chemoreceptors regulate breathing in response to CO₂, O₂, and pH levels. Understand how hyperventilation affects breath-holding time and why neural input anticipates respiratory changes during exercise.

Discover the difference between minute ventilation (total air movement) and alveolar ventilation (effective gas exchange). Learn how dead space reduces efficiency and why deep breaths improve oxygenation more than rapid, shallow breathing.

Explore how the lungs regulate airflow and blood flow to optimize gas exchange. Learn how low alveolar O₂ causes vasoconstriction, high CO₂ triggers bronchodilation, and how mismatches (shunts and dead space) impair oxygenation.

Understand how partial pressure gradients drive oxygen and CO₂ exchange between alveoli and blood. Learn how Fick’s Law explains the role of surface area, diffusion distance, and membrane thickness in efficient gas exchange.

Learn how CO₂ is transported in the blood as bicarbonate (HCO₃⁻), bound to hemoglobin, and dissolved in plasma. Explore the carbonic acid-bicarbonate buffer system, the chloride shift, and how CO₂ regulates blood pH.

Explore how oxygen travels bound to hemoglobin or dissolved in plasma, and how the oxygen-hemoglobin dissociation curve reveals oxygen loading and unloading dynamics. Learn how pH, temperature, and CO₂ levels shift the curve to optimize oxygen delivery.