BIOL 2160 – 80+ Exam Questions on Respiratory System, Cardiovascular Physiology, Muscle Contraction – Louisiana State University

This document provides over 80 multiple-choice questions with verified correct answers, designed to help students prepare for Test 4 in BIOL 2160 (Human Physiology) at Louisiana State University. It covers a wide array of advanced topics in physiology, with a strong focus on the respiratory system, cardiac physiology, and muscle contraction mechanisms. Key respiratory topics include the conducting and respiratory zones, gas exchange, oxygen and carbon dioxide partial pressures, hypernea, and the role of CO₂ in blood pH regulation. The cardiovascular section focuses on cardiac anatomy, valve dynamics, SA and AV node function, pacemaker potentials, and electrophysiology of cardiac muscle, including the significance of long cardiac action potentials and their role in preventing tetanus. Additionally, the document revisits crucial muscle physiology concepts, including the neuromuscular junction, cross-bridge cycling, ATP hydrolysis, DHP and ryanodine receptors, fast vs. slow twitch fibers, and smooth muscle contraction regulation via calmodulin, MLCK, and phosphatases. This document is an excellent resource for students in biomedical sciences, pre-med, nursing, exercise physiology, kinesiology, and biological sciences. Its structured Q&A format promotes active recall and provides clear explanations of physiological processes essential for academic and clinical success. Keywords: respiratory system, gas exchange, alveoli, oxygen pressure, CO2 regulation, diaphragm, hypernea, cardiac physiology, SA node, AV node, pacemaker cells, funny channels, T-type calcium channels, heart valves, isovolumetric contraction, cross-bridge cycle, DHP receptor, ryanodine receptor, SERCA pump, ATP hydrolysis, skeletal muscle, smooth muscle, calmodulin, MLCK, phosphatase, muscle twitch, fast twitch, slow twitch