circulatory

• What is the function of plasma in blood?

  Transports blood cells, waste, and nutrients
• What are the main components of the circulatory system?

  Blood, vessels, heart
• What do red blood cells carry around the body?

  Oxygen
• Why do red blood cells have a biconcave shape?

  To increase surface area to volume ratio
• What is the role of haemoglobin in red blood cells?

  It binds oxygen
• What is a key feature of red blood cells regarding nuclei?

  They have no nuclei
• What is the function of white blood cells?

  Defence against microbes
• What do lymphocytes do?

  Form antibodies
• What is the function of phagocytes?

  Engulf and digest microbes
• What is the role of platelets in the blood?

  Blood clotting
• What are the main components of blood and their functions?

  • Red blood cells: transport oxygen
  • White blood cells: defend against infection
  • Platelets: aid in blood clotting
  • Plasma: transport blood cells, waste, and nutrients
• Which statements about red blood cell adaptations are true?

  Their shape allows a larger surface area
• What is the function of arteries?

  Carry blood away from the heart
• What type of walls do arteries have?

  Thick walls containing muscle and elastic fibres
• What is the pressure condition in arteries?

  High pressure with a pulse
• What is the function of veins?

  Carry blood into the heart
• What features do veins have?

  Large lumen and thin layers
• What prevents backflow of blood in veins?

  Valves
• What is the role of capillaries?

  Link arteries and veins
• What is a characteristic of capillaries?

  Narrow with a tiny lumen
• What do capillaries allow to move in and out?

  Glucose, O₂, and CO₂
• What is the double circulatory system?

  Right ventricle to lungs, left ventricle to body
• What controls the natural resting heart rate?

  Cells in the heart
• What happens if coronary arteries are blocked?

  Heart attack occurs
• What do stents do?

  Keep coronary arteries open
• What is coronary heart disease (CHD)?

  Fatty material builds up in arteries
• What do statins do?

  Lower blood cholesterol levels
• What are mechanical valves made from?

  Titanium and polymers
• What is a disadvantage of mechanical valves?

  Require lifelong medication
• What are biological valves made from?

  Pigs, cattle, or humans
• What is a disadvantage of biological valves?

  Only last 12-15 years
• What do artificial pacemakers do?

  Connect irregular heart rates
• What is the purpose of an artificial heart?

  Keep patients alive while waiting for transplant
• What is a risk associated with artificial hearts?

  Blood clotting
• What is the circulatory system made up of?

  Heart and blood vessels
• What are the four chambers of the heart?

  Atria and ventricles
• What happens during inhalation?

  Intercostal muscles contract and diaphragm flattens
• What is the effect of inhalation on thorax volume?

  Increases volume of thorax
• What happens during exhalation?

  Intercostal muscles relax and diaphragm pushes up
• What is the effect of exhalation on thorax volume?

  Decreases volume of thorax