3.2.1 Circulatory systems

• The circulatory system transports blood throughout the body via arteries, veins, and capillaries
• The atria are the lower chambers of the heart that pump blood out of the heart.

  False
• The atrioventricular valves prevent the backflow of blood between the atria and ventricles.

  True
• Arrange the pathway of blood flow through the heart in the correct order:

  1️⃣ Deoxygenated blood flows into the right atrium

  2️⃣ Blood passes through the tricuspid valve into the right ventricle

  3️⃣ Blood is pumped through the pulmonary valve to the lungs

  4️⃣ Oxygenated blood returns to the left atrium

  5️⃣ Blood passes through the mitral valve into the left ventricle

  6️⃣ Blood is pumped through the aortic valve into the aorta
• Which valve does blood pass through to enter the right ventricle?

  Tricuspid valve
• From the right ventricle, blood is pumped through the pulmonary valve into the pulmonary arteries.
• Oxygenated blood flows back to the left atrium.
• The circular pathway of blood flow ensures that deoxygenated blood is continuously oxygenated.
• Blood becomes oxygenated in the lungs.


  True
• What are the two main types of circulatory systems?

  Open and closed
• Match the circulatory system type with an example organism:

  Open circulatory system ↔️ Insects

  Closed circulatory system ↔️ Vertebrates
• In a closed circulatory system, blood remains confined to arteries, veins, and capillaries.


  True
• Why is an open circulatory system suitable for smaller organisms?

  Lower blood pressure
• The heart has four main chambers.
• Match the heart valve with its function:

  Atrioventricular (AV) valves ↔️ Prevent backflow of blood

  Semilunar valves ↔️ Prevent backflow at ventricle exits
• The AV valves are located between the atria and ventricles.


  True
• What type of blood do veins carry back to the heart?

  Deoxygenated blood
• Which heart chamber does deoxygenated blood first enter?

  Right atrium
• What is an advantage of a closed circulatory system?

  Efficient oxygen delivery
• The circulatory system plays a critical role in transporting oxygen, nutrients, hormones, and waste products throughout the body
• The circulatory system comprises the heart, blood vessels, and blood
• What are the three main types of blood vessels?

  Arteries, veins, capillaries
• Veins contain valves to prevent the backflow of blood.


  True
• Match the blood vessel type with its structure:

  Arteries ↔️ Thick, elastic walls

  Veins ↔️ Thinner walls with valves

  Capillaries ↔️ Thin walls
• Blood passes through the tricuspid valve into the right ventricle
• Which valve prevents backflow of blood from the left ventricle into the left atrium?

  Mitral valve
• In an open circulatory system, blood directly bathes tissues
• What type of circulatory system has blood that empties from vessels into body cavities (hemocoel)?

  Open circulatory system
• The pressure in an open circulatory system is low
• Match the examples with their corresponding circulatory systems:

  Insects ↔️ Open circulatory system

  Vertebrates ↔️ Closed circulatory system
• What type of circulatory system has blood that circulates within blood vessels?

  Closed circulatory system
• A closed circulatory system ensures efficient delivery of oxygen and nutrients.


  True
• What are the four chambers of the human heart?

  Two atria and ventricles
• Red blood cells in blood are responsible for carrying oxygen
• The circulatory system helps maintain the body's homeostasis.


  True
• Arteries have thick, elastic walls to withstand high pressure
• Why do veins have thinner walls compared to arteries?

  To accommodate low pressure
• What do red blood cells transport from the lungs to the body's tissues?

  Oxygen
• Blood helps maintain the body's metabolic needs and homeostasis.


  True
• Match the heart valve with its location:

  Atrioventricular (AV) valves ↔️ Between atria and ventricles

  Semilunar valves ↔️ At the exits of the ventricles