cardiovascular
The cardiovascular system is responsible for pumping blood around the body to supply oxygen and nutrients and remove waste like CO₂. It includes:
• Heart – A muscular organ that pumps blood.
• Blood vessels – Arteries, veins, and capillaries.
• Blood – Carries oxygen, nutrients, and waste.
1. Label the Heart with the Four Chambers
The heart has four chambers:
1. Right Atrium – Receives deoxygenated blood from the body via the vena cava.
2. Right Ventricle – Pumps deoxygenated blood to the lungs via the pulmonary artery.
3. Left Atrium – Receives oxygenated blood from the lungs via the pulmonary vein.
4. Left Ventricle – Pumps oxygenated blood to the body via the aorta.
2. Structure of the Left Side vs. Right Side of the Heart
• Left side:
• Thicker walls (especially the left ventricle).
• Pumps oxygenated blood at high pressure to the whole body.
• Right side:
• Thinner walls.
• Pumps deoxygenated blood to the lungs at lower pressure.
3. Function of the Atrioventricular (AV) Valves
• Tricuspid Valve (Right side) and Bicuspid Valve (Left side) separate the atria and ventricles.
• Function:
• Prevent backflow of blood.
• Ensure blood moves in one direction (from atria to ventricles).
4. Blood Flow Through the Heart
1. Deoxygenated blood enters the right atrium from the body via the vena cava.
2. It moves into the right ventricle and is pumped to the lungs through the pulmonary artery.
3. Oxygenated blood returns from the lungs to the left atrium via the pulmonary vein.
4. It moves into the left ventricle, which pumps it to the body via the aorta.
5. Why Humans Have a Double Circulatory System
• Two circuits:
• Pulmonary circulation – Heart → Lungs → Heart.
• Systemic circulation – Heart → Body → Heart.
• Advantages:
• Keeps oxygenated and deoxygenated blood separate.
• Ensures high pressure and efficient oxygen delivery.
6. Blood Pressure and Blood Vessel Structure
• Arteries: High pressure, thick walls, elastic fibers for recoil.
• Arterioles: Lower pressure than arteries due to friction.
• Capillaries: Low pressure, thin walls for gas exchange.
• Veins: Lowest pressure, wide lumen, valves to prevent backflow.
7. Key Blood Vessels and Their Functions
• Aorta – Carries oxygenated blood to the body.
• Pulmonary Artery – Carries deoxygenated blood to the lungs.
• Pulmonary Vein – Brings oxygenated blood from the lungs to the heart.
• Vena Cava – Returns deoxygenated blood from the body to the heart.
8. Why Large Organisms Need a Circulatory System
1. Diffusion alone is too slow for oxygen delivery.
2. Large organisms have a small surface area-to-volume ratio (SA:V).
3. High metabolic rates need a faster oxygen supply.
9. Blood Pressure Readings
• Systolic pressure – When the heart contracts (higher number).
• Diastolic pressure – When the heart relaxes (lower number).
Complete Summary and Answers to All Questions
Cardiovascular System Overview
The cardiovascular system transports blood, oxygen, and nutrients while removing waste like CO₂. It includes:
• Heart – Pumps blood around the body.
• Blood vessels – Arteries, veins, capillaries.
• Blood – Carries oxygen, nutrients, and waste.
1. Label the Heart with the Four Chambers
The heart has four chambers:
1. Right Atrium – Receives deoxygenated blood from the body via the vena cava.
2. Right Ventricle – Pumps deoxygenated blood to the lungs via the pulmonary artery.
3. Left Atrium – Receives oxygenated blood from the lungs via the pulmonary vein.
4. Left Ventricle – Pumps oxygenated blood to the body via the aorta.
2. Structure of the Left Side vs. Right Side of the Heart
• Left side:
• Thicker muscular walls (especially the left ventricle).
• Pumps oxygenated blood at high pressure to the whole body.
• Right side:
• Thinner walls.
• Pumps deoxygenated blood to the lungs at lower pressure.
Why is the left side more muscular?
• The left ventricle pumps blood to the entire body, requiring higher pressure.
• The right ventricle only pumps blood to the lungs, which are nearby.
3. Function of the Atrioventricular (AV) Valves
• Tricuspid Valve (Right side) and Bicuspid Valve (Left side) separate the atria and ventricles.
• Function:
• Prevent backflow of blood.
• Ensure blood moves in one direction (from atria to ventricles).
Other valves:
• Semi-lunar valves (Pulmonary and Aortic) prevent backflow into the ventricles.
4. Blood Flow Through the Heart
1. Deoxygenated blood enters the right atrium from the body via the vena cava.
2. Blood moves into the right ventricle and is pumped to the lungs through the pulmonary artery.
3. Oxygenated blood returns from the lungs to the left atrium via the pulmonary vein.
4. Blood moves into the left ventricle, which pumps it to the body via the aorta.
5. Why Humans Have a Double Circulatory System
• Two circuits:
• Pulmonary circulation – Heart → Lungs → Heart.
• Systemic circulation – Heart → Body → Heart.
• Advantages:
• Keeps oxygenated and deoxygenated blood separate.
• Ensures high pressure and efficient oxygen delivery.
• Allows full oxygenation of blood before it reaches tissues.
6. Blood Pressure and Blood Vessel Structure
• Arteries: High pressure, thick walls, elastic fibers for recoil.
• Arterioles: Lower pressure than arteries due to friction.
• Capillaries: Low pressure, thin walls for gas exchange.
• Veins: Lowest pressure, wide lumen, valves to prevent backflow.
What happens to blood pressure as blood moves away from the heart?
• Highest in the aorta due to strong ventricular contractions.
• **Drops
6. Blood Pressure and Blood Vessel Structure
• Arteries: High pressure, thick walls, elastic fibers for recoil.
• Arterioles: Lower pressure than arteries due to friction.
• Capillaries: Low pressure, thin walls for gas exchange.
• Veins: Lowest pressure, wide lumen, valves to prevent backflow.
What happens to blood pressure as blood moves away from the heart?
• Highest in the aorta due to strong ventricular contractions.
• Drops in arteries but still fluctuates with heartbeats (pulse).
• Lower in arterioles due to increased resistance.
• Lowest in veins because of their large lumen and lack of strong pulses.
7. Key Blood Vessels and Their Functions
• Aorta – Carries oxygenated blood to the body.
• Pulmonary Artery – Carries deoxygenated blood to the lungs.
• Pulmonary Vein – Brings oxygenated blood from the lungs to the heart.
• Vena Cava – Returns deoxygenated blood from the body to the heart.
8. Why Large Organisms Need a Circulatory System
1. Diffusion alone is too slow for oxygen delivery.
2. Large organisms have a small surface area-to-volume ratio (SA:V), making diffusion inefficient.
3. Higher metabolic rate requires a faster supply of oxygen and nutrients.
9. Blood Pressure Readings
• Systolic pressure – When the heart contracts (higher number).
• Diastolic pressure – When the heart relaxes (lower number).
10. Additional Key Concepts
Mass Flow in Circulation
• Blood moves in one direction from high pressure to low pressure.
Oxygen Transport
• Oxygen is carried by red blood cells (hemoglobin binds to oxygen).
Blood in the Lungs
• Blood moves slowly through the lungs to maximize gas exchange.