3.2 Animal transport

• What is the function of the SA node in the heart?

  It initiates the heartbeat.
• What is tachycardia?

  It is an abnormally fast heart rate.
• What does an ECG measure?

  It measures the electrical activity of the heart.
• What are the three types of blood vessels?

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

  To carry blood away from the heart.
• What are capillaries responsible for?

  Exchanging gases and nutrients with tissues.
• What do venules do?

  They transport blood from capillaries to veins
• What is the role of the septum in the heart?

  It separates the left and right sides of the heart preventing oxygenated and deoxygenated blood from mixing
• What happens in diastol?

  • atria and ventricles are relaxed
  • blood passively flows into atria from veins
  • AV valves open as pressure in atria is greater than pressure in ventricles
• What happens during atrial systole?

  • atria contract
  • volume decreases - pressure increases
  • blood is forced through already open AV valves
• What happens in ventricular systole?

  • ventricles contract
  • volume decreases and pressure increases
  • AV valves close
  • Semi-lunar valves open
  • blood flows into arteries
• Why do multicellular animals need transport systems?

  They have a small surface area and high metabolic rate
• What are the types of circulation in animals?

  • Open circulation: blood can diffuse out of vessels (e.g., insects)
  • Closed circulation: blood always contained in vessels (e.g., mammals)
• How does blood flow in single circulation?

  Blood flows through the heart once in one circuit
• How does blood flow in double circulation?

  Blood flows through the heart twice in one circuit
• What are features of arteries?

  Thick, muscular walls to handle high pressure
• What is the function of elastic tissue in arteries?

  Helps resist pressure surges without bursting
• What do arterioles do?

  Branch off arteries to feed blood into capillaries
• What is the structure of capillary walls?

  One cell thick for efficient diffusion
• What do veins do?

  Carry blood back to the heart
• What is the function of valves in veins?

  Prevent backflow of blood
• What does tissue fluid supply to cells?

  Oxygen, nutrients, and essential materials
• What does plasma contain?

  Water, dissolved gases, nutrients, and waste products
• What is lymphatic fluid?

  Fluid that drains from tissues into lymphatic system
• What is the role of the lymphatic system?

  Drains excess tissue fluid and returns it to blood
• What is hydrostatic pressure?

  The pressure exerted on the sides of a vessel by a fluid

  • Highest at arteriole end of capillary
• What is oncotic pressure?

  The movement of water into blood by osmosis due to the tendency of plasma proteins to lower the water potential of the blood
• What is the role of the sinoatrial node?

  It acts as the heart's natural pacemaker
• How does the sinoatrial node affect heart rate?

  It initiates an electrical impulse
• What is the function of the atrioventricular node?

  It delays the wave of excitation and then passes it between the ventricles, along the bundle of his and purkinje fibres to enable the ventricles to contract
• What happens during the cardiac cycle?

  The heart contracts and relaxes to pump blood
• What is cardiac output?

  Heart rate x stroke volume
• What is the primary function of the circulatory system?

  To transport nutrients, gases, and waste products
• What is the role of chloride shift?

  It involves chloride ions across RBC membrane.
• What does positive pressure do in fluid movement?

  It moves substances out to tissue fluid.
• What does negative pressure do in fluid movement?

  It moves substances into capillary blood.
• What is the role of hemoglobin in RBC?

  It carries oxygen.
• How are hemoglobin groups transported in the body?

  They are carried around the body and released as needed.
• What effect does partial pressure of oxygen have on hemoglobin?

  Higher pressure increases hemoglobin affinity for oxygen.
• What happens to oxygen release at low partial pressure?

  Oxygen is released from hemoglobin.