What does the circulatory system do?
It circulates oxygen around your body, moves carbon dioxide out of the body, and moves nutrients to the cells in your body.
How many chambers does a mammal/bird heart have?
Four chambers separated by four valves.
How many chambers does a fish heart have?
Two chambers separated by one valve.
Where does deoxygenated blood come from? Where does it go?
It comes back from the body via veins into the superior and inferior vena cava.
[ Right Atrium ]
When deoxygenated blood enters the right atrium, where does it go next?
It enters the right ventricle through the tricuspid (AV) valve, and moves from here to the pulminary artery via the semilunar (SV) valve.
Which is the only artery that carries deoxygenated blood? Why does it do so?
The pulminary artery. This artery carries deoxygenated blood to the capillaries surrounding your alveoli inside your lungs where they collect oxygen.
How does diffusion occur in the circulatory system?
Oxygen from the alveoli move to the blood through capillaries lining the alveolar walls.
Which are the only veins that carry oxygenated blood? Why do they do so?
The pulminary veins. They are veins connected to your heart via the lungs and are responsible for carrying oxygen rich blood back to the left chamber to circulate around the body.
How is oxygen rich blood circulated through the body?
Oxygenated blood enters the left atrium via the pulminary veins. This blood moves from the atrium to the ventricle through the bicuspid (AV) valve, and is pumped into a large artery called the aorta.
How do arteries and veins transfer blood between each other?
Via capillaries. Arteries connect to arterioles which connect to capillaries. These capillaries are connected on the other side to venules and then to veins.
Which side of the heart is responsible for oxygenated blood?
The left.
Which side of the heart is responsible for deoxygenated blood?
The right.
What is the role of capillaries?
Capillaries are a network of vessels that sit between arteries and veins. They allow oxygen, waste products, and other ions and molecules to be transferred to and from the blood, in order to reach the surrounding tissues and organs.
What is the structure of an artery?
A three layered tubular structure with a small lumen, and thick elastic muscular wall. The small lumen and muscular walls ensure the high pressure needed to transport the blood through the body is met.
What is the structure of a vein?
A three layered tubular structure with thin walls, a large lumen, and valves to prevent backflow. The larger lumen allows the vein to carry a higher volume of blood back to the heart. The blood moves at a low pressure due to the thin walls and large lumen, so valves prevent the blood from flowing backwards.
What is the structure of a capillary?
A single layered tubular structure of epithelial cells called the endothelial layer. Capillary walls are one cell in thickness so that molecules can easily pass through them.
How does the heart beat?
The sinoatrial node (SAN) initiates the electrical impulse that controls the heartbeat. The signal passes across the atria to the atrioventricular node (AVN) where it is slowed to allow the atria to contract together (atrial systole). The impulses then pass down the bundle of His to the Purkinje fibres where it spreads over the ventricles. This causes the ventricles to contract simultaneously (ventricular systole). The heart then relaxes (diastole).
What are the words for when the heart contracts and relaxes?
Systole (contract), Diastole (relax)
Where are the papillary muscles? What purpose do they serve?
In both the left and right ventricles. They contract (ventricular systole) and push blood through the arteries. These muscles are more powerful because they have to send blood at a high pressure through the body. The left side is stronger/thicker than the right as it sends blood further.
What supplies the muscle in your heart with blood?
Coronary arteries.
What artery carries blood to the brain?
Carotid artery.
What are the "heartstrings" called? What function do they serve?
Chordae tendinae. These attach the valves in the heart to the papillary muscle in the ventricles and prevent the cusps from swinging back into the atrial cavity during systole (contraction).
What type of circulatory system do mammals have?
Closed circulatory system.
What type of circulatory system do fish have?
Single circulatory system.
How does the fish circulatory system differ?
They have a single circulatory system. Blood only passes through their heart once to complete a full circuit of the body. The heart only has two chambers, one atrium and one ventricle. The heart only reeives deoxygenated blood and blood receives oxygen from the gills after being pumped from the heart. (Blood pressure is also lower than in a double/closed circulatory system).