Transportation in Humans: The Circulatory System
The muscular pump and transport vessels distributing oxygen and nutrients.
The human circulatory system is a closed system that transports respiratory gases, nutrients, hormones, and waste products. It consists of the heart (the muscular pump), blood vessels, and blood.
Oxygenated blood is pumped to the body tissues, and deoxygenated blood is pumped to the lungs. This process involves double circulation, passing through the heart twice in one complete circuit.
Key Takeaways
- •The human heart has four chambers: two atria and two ventricles, preventing mixing of oxygenated and deoxygenated blood.
- •Arteries carry blood away from the heart (high pressure); veins carry blood toward the heart (lower pressure, valves present).
- •Capillaries are single-cell thick vessels where gas and nutrient exchange occurs.
Core Concepts & Definitions
1Heart Anatomy & Double Circulation
Systemic circulation delivers oxygenated blood from the left ventricle to the body, returning deoxygenated blood to the right atrium. Pulmonary circulation sends deoxygenated blood from the right ventricle to the lungs, returning oxygenated blood to the left atrium.
•Valves (tricuspid, bicuspid, semi-lunar) prevent backflow of blood.
•[INSERT: Internal cross-sectional diagram of human heart showing chambers and valves]
Quick Revision Notes
- •Always verify units and maintain coordinate systems.
- •Check boundary conditions and reference variables before applying formulas.
- •Ensure decimal precision is correct on output results.
Equations & Calculation Methods
Cardiac Output Equation
Calculates the volume of blood pumped by the heart per minute, typically around 5 liters/minute at rest.
Step-by-Step Worked Examples
Calculating Cardiac Output
Problem: An athlete has a resting heart rate of 60 beats/min and a stroke volume of 80 mL per beat. Calculate their cardiac output.
Step-by-step Solution:
- 1Stroke Volume (SV) = 80 mL/beat = 0.08 liters/beat.
- 2Heart Rate (HR) = 60 beats/min.
- 3Cardiac Output (CO) = SV x HR = 0.08 x 60 = 4.8 liters per minute.
Topic FAQ
Veins carry blood under low pressure back to the heart. Valves prevent backflow caused by gravity. Arteries carry blood at high pressure directly from the heart, which keeps blood moving in one direction.
Related Topics
Lab Experiment: Effect of Exercise on Heart Rate
Required Materials
- Stopwatch
- Stethoscope (optional)
- Resting stool
Procedure Steps
- 1Sit quietly for 3 minutes and count resting pulse rate (beats per minute) at the radial artery on the wrist.
- 2Perform intensive physical activity (like jumping jacks) for 2 minutes.
- 3Immediately measure and record post-exercise pulse rate.
- 4Measure pulse rate every minute after exercise until it returns to the resting baseline.
- 5Plot a line graph showing heart rate recovery curve over time.
Practice Quiz & Interactive Assessment
Syllabus Review Mode
0 🔥
0 in a row
Printable Worksheet: Heart Anatomy and Double Circulation
Classroom Homework Questions
- Q1.Differentiate between arteries, veins, and capillaries.
- Q2.Explain double circulation and state its significance in birds and mammals.
- Q3.Label a schematic representation of double circulation showing lungs, heart, and body organs.
- Q4.What is lymph? State its functions and how it differs from blood.
Frequently Asked Questions
Veins carry blood under low pressure back to the heart. Valves prevent backflow caused by gravity. Arteries carry blood at high pressure directly from the heart, which keeps blood moving in one direction.