closed+open circulatory systems

• What are the two types of circulatory systems?

  Open and closed circulatory systems
• How does an open circulatory system function?

  Blood is pumped at low pressure into spaces
• What is the role of the haemocoel in an open circulatory system?

  It allows blood to bathe tissues directly
• What is a key difference in blood pressure between open and closed circulatory systems?

  Open systems have low pressure; closed systems have high pressure
• How does blood return to the heart in an open circulatory system?

  Blood slowly returns through valves and muscle contractions
• What is the function of the tracheae in insects?

  Transport oxygen directly to tissues
• What type of circulatory system do earthworms have?

  Closed circulatory system
• How does blood circulate in a closed circulatory system?

  Blood circulates in a continuous system of vessels
• What is the role of the pseudohearts in earthworms?

  They pump blood at high pressure
• What is the function of tissue fluid in a closed circulatory system?

  It bathes organs and tissues
• What are the two types of closed circulatory systems?

  Single and double circulatory systems
• How does single circulation work in fish?

  Blood passes through the heart once per circuit
• What is the pathway of blood in fish?

  Heart to gills to tissues
• What is the difference between pulmonary and systemic circulation in mammals?

  Pulmonary goes to lungs; systemic goes to body
• What are the advantages of double circulation in mammals?

  It separates oxygenated and deoxygenated blood
• Why is high blood pressure maintained in systemic circulation?

  To ensure greater oxygenation of tissues
• What prevents hydrostatic pressure from forcing tissue fluid into the alveoli?

  Lower blood pressure in pulmonary circulation
• Where is the heart located in insects?

  It pumps blood through the aorta
• What do ostia do in insect circulatory systems?

  Allow blood back into the heart
• What is the function of the dorsal vessel in earthworms?

  It functions as the heart
• What do aortic arches do in earthworms?

  They function as accessory hearts
• What do ventral vessels serve in earthworms?

  They serve the body wall and intestine