Circulation Flashcards
Why do large multicellular organisms need transport systems?
They have a small surface area to volume ration and high metabolic rate, therefore the rate of diffusion alone would not be fast enough to transport substances to where they are needed.
Give four examples of substances transported within organisms
-Oxygen is transported in for respiration
-Co2 is transported out from respiration
-Dissolved food molecules from digestion
-Waste products such as urea in humans
What is mass transport?
The bulk transport of substances to all parts of an organism using mass flow.
Give features of a mass transport system
-Vassels
-Transport medium
-A mechanism for maintaining a flow
What are the difference in function between veins. arteries, and capillaries?
-Arteries carry blood away from the heart
-Veins carry blood towards (into) the heart
-Capillaries flow close to tissues for exchange
Describe the structure of arteries
They have thick walls made of muscle and elastic tissue and a small lumen to transport blood under high pressure.
Describe the structure of capillaries
They have thin walls about one cell thick to allow for the easy exchange of substances at the tissue.
Describe the structure of veins
Veins have less muscle and elastic tissue than arteries and they have a larger lumen as the blood is at lower pressure. They also have valves to prevent backflow.
What is the name of the main artery which take oxygenated blood out of the heart for transport around the body?
The aorta
What is the name of the main vein which carries deoxygenated blood from the body into the heart?
The vena cava
What is the name of the main artery which takes oxygenated blood out of the heart for transport around the body?
The coronary artery
What is the name of the artery which transports deoxygenated blood from the heart to the lungs?
The pulmonary artery
