circulatory system

• what is the role of the circulatory system

  Distributes nutrients, oxygen, hormones, and functions waste retrieval
• which organs make up the circulatory system

  heart and blood vessels
• How is this system adapted to maximize transport

  strong heart, elastic arteries, thin walled capillaries, and vein valves
• Why can't larger multicellular organisms rely on diffusion


  they have increased distances between cells and surfaces
• function of adapted transport systems (4)

  - meet high metabolic demands

  - overcome the decreasing SA:V

  - allow movement of hormones

  - remove waste products of metabolism
• what are the Key features of a transport system

  1. They need a suitable transport medium

  2. they need a network of tubes/vessels to carry the transport medium

  3. They need a way of making sure they travel in the right direction

  4. They need a means of ensuring fast supply to meet demand
• what is a suitable transport medium

  blood
• what is the network of tubes and vessels

  arteries

  veins

  capillaries
• how do they ensure fast supply/supply to meet demand

  Double system means high pressure and fast flow
• what are the two transport systems

  open and closed
• where are open circulatory systems usually found

  invertebrates
• What is the function of the circulatory system in certain organisms?

  It transports food and waste products but does not transport substances from gas exchange.
• How does an open circulatory system function in insects

  The transport medium is pumped into a cavity called a haemocoel,
• What is the haemocoel?

  The primary body cavity of most invertebrates, containing circulatory fluid
• what is the transport medium in insects called

  haemolymph
• where is the position of the heart in insects

  extends along the thorax and abdomen
• how is the diffusion of substances taking place in insects

  Transport medium in haemocoel is in direct contact with tissues
• what is an issue with open systems ?

  Steep diffusion gradients can't be maintained, volumes can't be varied to meet demand
• What type of circulatory system do all mammals have

  A closed circulatory system.
• What are the key features of a closed circulatory system?

  1. The transport medium is within vessels and not in direct contact with cells.

  2. Blood flow can be regulated by altering the diameter of blood vessels to meet demand.
• What are the two types of closed circulatory systems

  Single closed circulatory systems and double closed circulatory systems
• Is the human circulatory system open or closed


  a closed circulatory system.
• Is the human circulatory system single or double?


  It is a double circulatory system.
• Why is the human circulatory system classified as double?

  Because blood travels through the heart twice per circulation—once through the pulmonary circuit and once through the systemic circuit.
• What are the two separate circulations in human

  Pulmonary circulation and systemic circulation.
• What happens in the pulmonary circulation

  Deoxygenated blood from the right side of the heart is pumped to the lungs.

  Blood gains oxygen in the lungs.

  Oxygenated blood returns to the left side of the heart.
• What happens in the systemic circulation?

  Oxygenated blood is pumped from the left side of the heart to the body.

  Tissues use the oxygen.

  Deoxygenated blood returns to the right side of the heart.
• What are the advantages of a double circulatory system?

  Oxygenated and deoxygenated blood are kept separate.
• what does separating oxygenated and deoxygenated blood allow for

  1. Allows specialization of blood vessels (arteries carry high-pressure blood, veins carry low-pressure blood).

  2. Ensures fast blood flow and high pressure, crucial for mammals with high metabolic demands.
• Where can single closed circulatory systems be found

  fish
• How many times does blood travel through the heart in a single circulatory system

  once per circulation
• How does a single circulatory system differ from a double circulatory system


  In a single circulatory system, blood passes through the heart once per circuit, while in a double circulatory system, it passes through twice.
• Why do animals with a single circulatory system generally have lower activity levels

  Because this system has limited efficiency in delivering oxygen and nutrients.
• Why are fish an exception to the low activity levels of animals with single circulatory systems

  Because their gills allow efficient oxygen exchange, compensating for the lower efficiency of their circulatory system.
• Do arteries take blood away from or towards the heart


  away from the heart
• Do arteries carry blood at high or low pressure

  high pressure
• what are the features of arteries

  1. They have thick, muscular walls

  2. They have elastic tissue

  3. The endothelium
• Why do arteries have thick muscular walls and elastic tissue?

  To withstand high pressure, maintain continuous blood flow, and allow flexibility.
• What are the key components of artery walls?

  Elastin, smooth muscle, and collagen.
• What is the function of elastin in arteries?

  It allows arteries to stretch and recoil to maintain blood flow