A single heartbeat comprises ________ distinct stages.
Show answer Hide answer
Answer: C. 3
Explanation
The cardiac cycle consists of three distinct functional stages during every normal single heartbeat. Atrial systole first forces blood into the ventricles before ventricular systole pumps it outward. Complete cardiac diastole finally allows the heart chambers to relax and refill with returning blood. A cardiac cycle represents the complete sequence of events in a single normal human heartbeat. During systole, heart muscle chambers contract to actively eject blood through the circulatory system. During diastole, heart muscle chambers relax completely to allow passive filling from major veins.
Understanding the cardiac cycle helps medical professionals diagnose various arrhythmias and heart valve failures. Physicians listen to specific heart sounds generated by valve closures during these distinct cycle stages. Abnormal timing within these three stages can quickly lead to reduced cardiac output and fatigue. Option one fails because a single heartbeat involves multiple coordinated mechanical and electrical stages. Option two is incorrect because stopping at two stages ignores either atrial or diastolic events. Option four incorrectly adds an extra stage that does not exist in standard cardiac physiology.
Related questions
Q1. A 0.4 cm stone obstructing the renal pelvis outlet causes mild-to-moderate tract blockage. Which method should be selected to extract this stone?
Show answer Hide answer
Answer: C. Extracorporeal Shock wave lithotripsy
Extracorporeal shock wave lithotripsy is a non-invasive medical procedure used to break up small kidney stones using acoustic shock waves. High-energy sound waves pass through body tissues to shatter the renal stone into...
Q2. An Antarctic sponge exceeding one meter in height is____________?
Show answer Hide answer
Answer: A. Scolymastra joubini
Scolymastra joubini is a giant hexactinellid glass sponge found in Antarctic waters that can exceed one meter in height. These long-lived marine organisms thrive in extremely cold, stable polar benthic environments. Sili...
Q3. A substance that binds to an enzyme's active site without producing any products is termed________________?
Show answer Hide answer
Answer: C. Competitive inhibitor
A competitive inhibitor binds reversibly to the active site of an enzyme, competing directly with the substrate without forming a product. Structural similarity allows the inhibitor to fit into the active site and block...
Q4. A map line linking locations that receive identical solar radiation is known as:________?
Show answer Hide answer
Answer: B. Isohel
An isohel is specifically defined as a contour line linking locations receiving identical sunshine duration. Meteorologists use these specialized map lines to analyze regional variations in solar radiation receipt. The p...
Q5. A standard metaphase chromosome featuring a median centromere is ________?
Show answer Hide answer
Answer: A. Metacentric
A metacentric chromosome features a median centromere that divides it into two equal arms. This central positioning creates a symmetrical V-shape when the chromosomes separate during cellular division. Standard metaphase...
Q6. A three-dimensional pocket with a specific charge through which an enzyme engages its substrate is termed_________________?
Show answer Hide answer
Answer: A. Active site
The active site is a three-dimensional pocket with specific charges where enzyme-substrate binding occurs. Its unique chemical environment enables enzymes to catalyze biochemical reactions with extreme molecular precisio...