B5.1

• What are the essential organ systems in the body?

  The circulatory system, digestive system, gas exchange system, and excretory system
• What is the function of partially permeable membranes in organ systems?

  They allow selective exchange of substances between the internal and external environments
• What components make up the circulatory system?

  The heart, blood vessels, and blood
• What do red blood cells do in the circulatory system?

  They transfer oxygen
• What is the role of plasma in the blood?

  It carries away waste
• What does the digestive system break food down into?

  Lipids, proteins, and carbohydrates
• What are the components of the gaseous exchange system?

  The nose, mouth, lungs, and intercostal muscles
• How do alveoli function in gas exchange?

  They transfer oxygen to red blood cells and carbon dioxide to the alveoli
• What is the excretory system responsible for?

  Filtering waste from blood for excretion
• What do cells need for exchange?

  Oxygen, water, and minerals
• What waste products do cells produce?

  Carbon dioxide, lactic acid, and ammonia
• Why are alveoli one cell thick?

  To allow faster diffusion of oxygen and carbon dioxide
• What role do capillaries play in the digestive system?

  They provide a network for faster exchange of nutrients
• What are villi in the small intestine?

  Finger-like projections that increase surface area for absorption
• How do kidneys filter blood?

  They filter waste into urine using nephrons
• How many nephrons are in the renal cortex?

  100 million
• What are the types of blood vessels?

  Arteries, veins, and capillaries
• What is the function of arteries?

  To take oxygenated blood away from the heart at high pressure
• What is the function of veins?

  To take deoxygenated blood towards the heart at low pressure
• What are capillaries?

  The smallest blood vessels that link veins and arteries
• What is the composition of plasma?

  It contains glucose, water, vitamins, and urea
• What percentage of blood is made up of plasma?

  55%
• What is the shape of red blood cells?

  They have a biconcave shape
• What is the function of white blood cells?

  To protect the body from infection and produce an immune response
• What are platelets?

  Small cell fragments that help in blood clotting
• What percentage of blood do platelets make up?

  Less than 1%
• How does deoxygenated blood enter the heart?

  Via the vena cava
• What happens to deoxygenated blood after it enters the heart?

  It passes the tricuspid valve and exits the right ventricle through the pulmonary artery
• Where does oxygenated blood go after leaving the lungs?

  It reenters the heart via the pulmonary vein
• What is the pathway of oxygenated blood through the heart?

  From the left atrium to the left ventricle via the mitral valve, then through the aortic valve to the body
• What is the function of heart valves?

  To prevent the backflow of blood
• What does the septum do in the heart?

  It separates both sides of the heart, preventing blood mixing
• Why is the left side of the heart thicker than the right side?

  It needs more muscle to apply more pressure and pump blood around the body