circulation ✩

• What is the primary function of the heart?

  To pump blood around the body
• What type of circulatory system does the heart operate in?

  A double circulatory system
• What does the right ventricle do?

  Pumps blood to the lungs
• What does the left ventricle do?

  Pumps blood around the rest of the body
• What is the role of the circulatory system?

  To transport oxygen and nutrients
• What are the three main components of the circulatory system?

  • Blood
  • Blood vessels
  • Heart
• What is the function of blood in the circulatory system?

  To carry oxygen and nutrients
• What do blood vessels do?

  Hold the blood
• What is the function of the heart in the circulatory system?

  To pump the blood
• Describe the two loops of the double circulatory system.

  1. Deoxygenated blood from the heart to the lungs, gains oxygen, returns to the heart.
  2. Oxygenated blood from the heart to the body, gives up oxygen, returns to the heart.
• How many chambers does the heart have?

  Four chambers
• What are the top chambers of the heart called?

  Atria
• What are the bottom chambers of the heart called?

  Ventricles
• What is the purpose of valves in the heart?


  To prevent blood from flowing backwards
• Describe the path blood takes through the heart.

  1. Blood flows into the heart via the vena cava and pulmonary vein.
  2. Enters right atrium and left atrium.
  3. Atria contract, pushing blood into ventricles.
  4. Ventricles contract, pushing blood into pulmonary artery and aorta.
  5. Cycle repeats.
• How many times does the heart cycle in a minute?

  70 times
• What is the role of pacemaker cells in the heart?

  To produce electrical impulses that cause heart contractions
• What is an artificial pacemaker?

  A device implanted to regulate heart contractions
• What is the difference between arteries and veins?

  • Arteries carry blood away from the heart.
  • Veins carry blood to the heart.
  • Arteries can carry deoxygenated blood (e.g., pulmonary artery).
  • Veins can carry oxygenated blood (e.g., pulmonary vein).
• What do coronary arteries do?

  Supply oxygenated blood to the heart muscle
• What are the three types of blood vessels?

  • Arteries
  • Capillaries
  • Veins
• What is the function of capillaries?

  To exchange nutrients and oxygen with tissues
• Why do arteries have thick walls?

  To withstand high pressures from pumped blood
• What is the significance of capillary walls being a single cell thick?

  It allows for easy diffusion of substances
• Why is blood pressure lower in capillaries compared to arteries?

  Because the total cross-sectional area of capillaries is much larger
• What do veins have to prevent blood from flowing backwards?

  Valves
• What is the rate of flow in the circulatory system?

  The amount of blood flowed over time
• What are the four main components of blood?

  Red blood cells, white blood cells, platelets, and plasma
• What is the primary function of red blood cells (RBC)?

  • Carry oxygen from lungs to body tissues
  • Facilitate cellular respiration
  • Contain haemoglobin to bind with oxygen
• What pigment do red blood cells contain that allows them to carry oxygen?

  Haemoglobin
• What is formed when haemoglobin binds with oxygen?

  Oxyhaemoglobin
• What happens to oxyhaemoglobin when it reaches body tissues?

  It splits back into oxygen and haemoglobin
• What is the shape of red blood cells and why is it beneficial?

  They are biconcave discs, providing a large surface area for oxygen absorption
• What percentage of blood do white blood cells (WBC) make up?

  Less than 1%
• What are the main functions of white blood cells (WBC)?

  • Defend against infections
  • Engulf pathogens (phagocytosis)
  • Produce antibodies to destroy pathogens
  • Produce antitoxins to neutralize toxins
• Do white blood cells have a nucleus?

  Yes, they have a nucleus
• What are platelets and what is their primary function?

  Platelets are small fragments of cells that help in blood clotting
• Do platelets have a nucleus?

  No, they do not have a nucleus
• How do platelets function when a cut occurs?

  • Rush to the wound site
  • Act like glue to patch the wound
  • Help prevent blood loss and infection
• What is plasma and what does it consist of?

  Plasma is a pale straw-colored liquid that makes up about half of blood's volume