B5.3/4 - The Circulatory System & Cardiac Cycle Flashcards
What is the circulatory system?
The system that circulates blood and lymph through the body, consisting of the heart, blood vessels, blood, lymph, and the lymphatic vessels and glands.
What is an open circulatory system?
An open circulatory system is when the system has no arteries or veins, but their blood floes freely through their body cavity.
How does an open circulatory system provide blood to the organs? In terms of insects.
The blood makes direct contact with the organs and tissues. Blood travels in the aorta from the heart up to the head. It bathes the organs and muscles of the head and then trickles back trough the body cavity. It passes over the gut and gets back into the heart through small holes.
How does an open circulatory system provide oxygen? In terms of insects.
The blood does not carry oxygen, because the breathing tubes deliver oxygen directly to the tissues. Their watery, greenish yellow blood carries amino acids, sugars, and ions. There are some cells to digest pathogens.
Vertebrates have a closed circulatory system. What is a closed circulatory system?
A closed circulatory system is where the blood is contained in blood vessels - arteries, veins, and capillaries.
How does blood circulate in a closed system? In terms of fish.
The blood circulates once around the body, from the heart to:
- The gills, where it collects oxygen and unloads carbon
- The body organs and tissues
The fish heart is a single pump consisting of two chambers.
Humans and other mammals have a _________ circulatory system. There are two circuits from the heart.
Double
Describe the circuit blood takes around a human body
Blood passes :
- from the heart to the body organs and tissues
- back to the heart
- to the lungs to remove carbon dioxide and collect oxygen
- back to the heart before being pumped out of the body again
Why does the human heart need four chambers and why does blood travel around the body quicker?
The blood makes two circuits from the heart, so the heart needs four chambers. It is a double pump. Blood in a double circulatory system is under high pressure and so it transports materials more quickly around the body.
What did Galen discover and how?
Galen cut open pigs and monkeys and noticed that blood was darker in the veins than in the arteries. He mistakenly thought that the liver made blood and pumped it in the veins to the organs which consumed it. Later on, Leonardo da Vinci passed studied anatomy and made drawings showing how blood passes through the heart chambers and how heart valves worked.
What did William Harvey discover?
He released that the pulse in the arteries was linked to the contraction of the left ventricle of the heart. He discovered that veins have valves to prevent back flow. He postulated that there were capillaries pm but did not see the as he did not have a microscope.
Explain why single called organisms do not need a circulatory system? In terms of amoebae(small organisms that live in water)
They do not need a circulatory system because they have a large surface area compared with their volume. They are surrounded by the water they live in. Dissolved oxygen diffuses from this water into the cell through the cell membrane. Waste material can also diffuse out of the cell. This is why there is no need for a special transport system.
