Circulatory System
Overview of Circulatory System The circulatory system is connected to all organ systems. It absorbs and transports nutrients and oxygen to cells and carries wastes (eg. CO2, urea) for elimination by other parts of the body (eg. Lungs, kidneys)
The circulatory system is made up of THREE components: Fluid (blood) Blood vessels (arteries, veins, capillaries) Pump (heart)
Blood and its Components
The Blood Blood Component Function Plasma Fluid medium carrying gases, nutrients and wastes Red blood cells Contains hemoglobin that binds to O2 to help transport it! White blood cells Protects body against bacteria/viruses, part of immune system Platelets Plays role in blood clotting
Blood Vessels There are three main types of blood vessels: Arteries – carry oxgenated blood (O2-rich) AWAY from heart to cells of body. Capillaries – tiny blood vessels that connect the arteries with the veins. Veins – carry deoxygenated blood (O2-poor) from cells of body TO heart
The mammalian heart consists of a double pump separated by the septum. Composed of cardiac muscle tissue, nervous tissue, epithelial tissue and connective tissue. Each pump consists of a thin-walled atrium and a thick-walled ventricle. Therefore the mammalian heart has four chambers: Right atrium Right ventricle Left atrium Left ventricle The Heart
Deoxygenated blood (O2 poor) from body’s cells needs to go to lungs to be oxygenated – must pass heart! Oxygenated blood (O2 rich) from lungs needs to go to body cells to be used – must pass heart! 1. Deoxygenated blood from the body cells flows through the vena cava into the right atrium. 4. Oxygenated blood from the lungs travels to the heart via the pulmonary veins and enters the left atrium. 2. Deoxygenated blood flows through tricuspid valve into the right ventricle. 5. Oxygenated blood flows through the left atrioventricular valve into the left ventricle. 3. The right ventricle pumps the deoxygenated blood through the pulmonary valve into the pulmonary arteries where it travels to the lungs. 6. The muscular left ventricle pumps the oxygenated blood through the aortic valve into the aorta where it travels to the body cells. Arteries carry blood away from the heart with the exception of the pulmonary arteries. Veins carry blood to the heart with the exception of the pulmonary veins.
Deoxygenated blood (O2 poor) from body’s cells needs to go to _____________ to be oxygenated – must pass heart! Oxygenated blood (O2 rich) from lungs needs to go to ____________________ to be used – must pass heart! 1. Deoxygenated blood from the __________________ flows through the _______ __________ into the _______ _____________. 4. Oxygenated blood from the ____________ travels to the heart via the ______________ ___________ and enters the ________________________. 2. Deoxygenated blood flows through tricuspid valve into the __________ ________________. 5. Oxygenated blood flows through the left atrioventricular valve into the ________ ____________________. 6. The muscular left ventricle pumps the oxygenated blood through the aortic valve into the ____________ where it travels to the ____________________. 3. The _______________________ pumps the deoxygenated blood through the pulmonary valve into the ______________________________ where it travels to the ___________.
Comparison of Vertebrate Hearts What is the advantage of having a 4-chambered heart over 2-chambered and 3-chambered hearts seen in fish and amphibians (eg. Frogs)? Fish Heart: 2 chambers (1 atrium and 1 ventricle). Blood travels from the atrium into the more muscular ventricle where it is pumped out to the gills where the blood becomes oxygenated. It then travels throughout the body, then back to the atrium where the process starts all over again. this is called single circuit circulation. Frog Heart: 3 chambers (2 atria and 1 ventricle), more efficient than fish heart with the additional chamber. It has a double circuit and allows blood to be pumped twice rather than once as seen in fish and with more efficiency. There is mixing of O2 rich and O2 poor blood. Frogs have a 3 chambered heart because they are amphibians, residing both on land and in water. On land, they breathe in air (O2 rich) through their lungs. In water, they breathe through their skin using capillaries under their skin. So one of the atrium is takes in blood from the body (including the skin, which is a respiratory organ for frogs) and the other atrium takes in blood from the lungs – depending on whether they are in water or on land. This system always ensure that there is some blood going to the lungs and back to the heart even though there is mixing of blood but there’s still oxygen in it regardless. Additionally, frogs are cold-blooded and have lower energy demands so this 3-chambered double circuit works for them as well. Human Heart: 4 chambers, no mixing of O2 rich and O2 poor blood and the pumps are more efficient. This is needed as we are warm-blooded and have more energy demands (and also need to regulate our body temperatures) and need a highly efficient pumping system to provide us with the O2 that we need in our blood to carry to our body’s cells. 2 chambers 3 chambers 4 chambers (eg. Fish) (eg. Frog) (eg. Human)