The circulatory system Flashcards
(10 cards)
Fish and Humans both have a closed circulatory system.What is a closed circulatory system?
A closed circulatory systems means that the blood is contained in blood vessels. ie. veins, Capillaries and arteries.
Why do you think insects do not have red blood cells or haemoglobin in their blood?
Insects do not have red blood cells or haemoglobin because their blood does not need to carry oxygen. This is because the insects breathing tube carries oxygen directly to the organs and tissues.
Explain why fish need only a two-chambered heart.
Fish only need a two chambered heart because blood goes from the heart to the gills and from the heart to the body organs.
Why do humans and other mammals need a four-chambered heart?
Mammals need a four-chambered heart because the blood is pumped from the heart to the lungs to come back to the heart which is then pumped around the body.
What contributions did William Harvey make to our understanding of the circulatory system?
William Harvey was a doctor in London. In his theory on the circulatory system, he explained that blood circulates from the heart to the lungs, and from the heart to the rest of the body. He was able to link the pulse in the arteries to the contractions of the left ventricle, and he realised that veins have valves to prevent the back flow of the blood.
What type of organism does not need a circulatory system?
singled-celled organism
Why do large animals need a circulatory system?
Because diffusion alone cannot efficiently transport substances to and from their cells. They need blood to do this.
Give an example of an organism that does not need a circulatory system.
Amoebae (bacteria)
What does insects blood contain?
Amino acids,sugars and ions.
Why is an insect circulatory system described as an open system?
Insects have an open circulatory system because it does not contain blood vessels. The blood flows freely through their body cavity.
