Organisation-lungs and heart

• What is the primary function of the lungs?

  Gas exchange
• What are the adaptations of gas exchange surfaces in the lungs?


  • Large surface area for faster diffusion
  • Thin walls for short diffusion distances
  • Good ventilation to maintain diffusion gradients
  • Dense capillary network for high concentration gradients
• How does breathing affect gas exchange in the lungs?


  Breathing maintains high oxygen levels and low carbon dioxide levels in the alveoli
• How many alveoli are there in each lung?


  Approximately 250 - 300 million
• What is the total surface area of each lung?


  About 70 m²
• What are the main structures of the lungs that should be identified?

  • Trachea
  • Bronchi
  • Alveoli
  • Capillary network
• What type of circulatory system does the human heart belong to?


  A double circulatory system
• What are the components of the circulatory system?


  • Blood vessels
  • A pump (the heart)
  • Valves for one-way blood flow
• What is the function of the right side of the heart?


  It pumps blood to the lungs for gas exchange
• What is the function of the left side of the heart?


  It pumps oxygenated blood under high pressure to the body
• What are the benefits of a double circulatory system?


  • Allows for gas exchange at lower pressure in the lungs
  • Increases pressure before sending oxygenated blood to the body
• What happens to deoxygenated blood in the lungs?


  Oxygen diffuses in and carbon dioxide diffuses out
• What are the two sets of chambers in the heart?

  • Atria (top chambers)
  • Ventricles (bottom chambers)
• What is the role of the coronary arteries?


  They supply the heart tissue with oxygenated blood
• What is the pathway of deoxygenated blood through the heart?


  It enters via the vena cava into the right atrium
• What happens when the ventricles contract?


  Blood travels up through the pulmonary artery to the lungs
• How does the left ventricle differ from the right ventricle?


  The left ventricle has a thicker wall to pump blood at high pressure
• What is the function of the septum in the heart?


  • Separates the two sides of the heart
  • Prevents mixing of deoxygenated and oxygenated blood
• What type of muscle tissue makes up the heart?

  Cardiac muscle tissue
• What is the role of the pacemaker in the heart?


  It coordinates the contraction of the heart muscle
• Where is the pacemaker located?


  In the right atrium
• What happens to heart rate during exercise?


  Heart rate increases to meet higher oxygen demand
• What is the function of artificial pacemakers?


  They correct irregularities in heart rate
• What are the three types of blood vessels?

  • Arteries
  • Veins
  • Capillaries
• What is the primary function of arteries?


  To transport blood away from the heart
• What is the primary function of veins?


  To transport blood to the heart
• What is the primary function of capillaries?


  To link arteries to veins within tissues
• How does the structure of arteries relate to their function?


  • Thick walls to withstand high pressure
  • Contain collagen, smooth muscle, and elastic fibers
  • Narrow lumen to maintain high blood pressure
• How does the structure of veins relate to their function?


  • Thinner walls with fewer layers
  • Larger lumen to accommodate low-pressure blood
  • Valves to prevent backflow
• How does the structure of capillaries relate to their function?


  • Walls consist of a single layer of endothelial cells
  • Minimizes diffusion distance for gases
  • Pores allow plasma to leak out and form tissue fluid
• How do you calculate the rate of blood flow?


  Rate of blood flow = volume of blood / time
• If 2460 ml of blood flows through a vessel in 4 minutes, what is the rate of blood flow?


  $615 \text{ ml/minute}$
• How much blood flows through the same vessel in one hour if the rate is 615 ml/minute?


  $36,900 \text{ ml}$
• What is the role of blood in the body?


  • Transports useful substances to cells
  • Removes harmful waste substances
  • Transfers heat from active organs to cooler parts
• What are the components of blood?

  • Plasma
  • Red blood cells
  • White blood cells
  • Platelets
• What shape do red blood cells have?


  Biconcave disc shape
• Why do red blood cells have a biconcave shape?


  To maximize the efficiency of gas diffusion
• What protein is packed in the cytoplasm of red blood cells?


  Haemoglobin
• What is formed when oxygen binds with haemoglobin?


  Oxyhaemoglobin
• What are the roles of white blood cells?


  • Defend the body from infection
  • Recognize and destroy pathogens