(These are notes derived from my Grade 11 biology teacher)
Sinoatrial Node
The sinoatrial node is the impulse generator, a bundle of neuron tissue located in the right atrium. Many different sources call it the natural pacemaker. The function is to, as is interpreted by the "pacemaker", sets the rate of contraction (muscle becomes or/is made shorter and tighter) for the heart. The atrioventricular node produces a "wave" of electrical activity over the atria (plural of Atrium) causing them to contract.
Atrioventricular Node
The atrioventricular node is part of the "electrical control system" of the heart. Its function is to controls/coordinates the top of the heart. It picks up part of the impulses and conducts it through the purkinje fibers.
Purkinje Fibers
Purkinje fiber branch off the atrioventricular node and is located in the septum. Its function is to conducts signals to the bottom of the ventricles this causes them to contract. In the purkinje fibers the impulse is conducted to the left and right ventricles.
Heart Sounds
The sound that your heart makes are due to the opening and closing of valves. The classic "Lubb-Dubb" sound.
Lubb
This is the first sound and is made when the atriolventricular valve closes during a ventricular contraction. The first sound lub, occurs when the atrioventricular valves close.
Dubb
This is when the blood is forced out of the ventricles during a contraction. At the end of the contraction the blood pressure begins to drop within the heart. The semilunar valve prevent the blood that wants to flow backwards into the ventricles. The second sound occurs when the semilunar valves close.
I would just like to start off by saying that non of the links and pictures are mine they are all ones that I found through the research of this project.
The Human Circulatory system and the Components of Blood
There are three essential parts to all Circulatory Systems a pump, fluid and Vessels.
Pump and Vessels
The Circulatory System of a human uses the heart as its pump and the vessels are what the blood travels along. For example veins, arteries and capillaries.
Double Circulation System
Flow of Blood Through The Heart
Blood returns to the right atrium through the superior/inferior vena cava
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The blood then flows through to the right ventricle and passes through the tricuspid valve
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From there the blood passes through the pulmonary semilunar valve and enters into the pulmonary trunk
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The blood is then pumped through the pulmonary arteries into both lungs
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The blood passes through the capillaries and oxygen sticks to the blood cells and carbon dioxide is released
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The blood then travels from the lungs through four pulmonary veins returning to the left atrium and the heart
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From there the blood enters the left ventricle through the bicuspid valve
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It is then pumped by the systemic circuit to the rest of the body
The Systemic Circuit
The Blood enters the aorta
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Through the aorta blood is transported through artery branches and capillaries
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Through the capillaries the oxygen in the blood is released to different body cells
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The blood that is low in oxygen returns to the heart through the superior vena cava
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They then return into the right atrium
Coronary Circulation
The coronary circulation is important because it is required to provide the heart muscle with oxygen. It consists of a left and right artery. The left artery contains two branches the cumflex artery and the anterior descending artery. Blockage of the coronary arteries is what causes a heart attack, usually the cause of the blockage is due to smoking, stress, lack of exercise and high cholesterol.
Arteries - The arteries are what carry the blood away from the heart. They contain three layers which are the epithelial cells, smooth muscle and connective tissue. The arteries may be thick and muscular, but it is able to stretch much like the vein.
Veins - The vein has elastic capabilities and contain valves even though the walls are thinner than that of arteries. Also opposite the arteries the veins are what carry the blood towards the heart.
Capillaries - Like the veins the capillaries contain thin walls they are very narrow in diameter and are one cell thick. The capillaries are used to exchange gases within cell tissue. There is a large quantity of them within the body.
Blood Pressure
Blood pressure is the amount of pressure that is exerted on the walls of the arteries. This is a side effect of the heart ejecting blood into the aorta with every beat. It is usually measured using a sphygmomanometer which temporarily stops the flow of blood through the brachial artery and slowly lowers the pressure of the cuff. An examiner uses a stethoscope to determine the systolic and diastolic pressure. Systolic pressure is when the aorta expands to gain the blood from the heart. According to Addison and Wesley Biology 11 “a wave of pressure is generated throughout all the arteries” (332). Diastolic pressure is measured when the aorta springs back which propels the blood through the arterioles and capillaries within the body. Also according to Addison and Wesley Biology 11 it is “the pressure that the blood exerts on the wall of the aorta/ when no blood leaves the heart”(332). The difference between is your pulse pressure.
Fluid
The second essential part of the human circulatory system is the fluid which in humans is the blood.
Blood can be separated into its individual components by the use of centrifuge. Centrifugation is the act of using a rotating force to separate a fluid into its individual components. When separating blood into its individual components a centrifuge is usually used. A centrifuge is a mechanical device that uses a motor to rapidly spin the test tube and using the spinning force it separates the blood into the individual components.
Centrifuge Operation.
After being separated by the centrifuge you can now see the different components of the blood. These components include Plasma which contains water, plasma proteins and other solutes. It also contains another formed element that contains red and white blood cells and platelets.
Components
Function
Plasma
According to the red cross website, plasma in the blood serves many different purposes. These functions include maintaining blood pressure and volume to aid in blood clotting and immunity. Plasma also aids in exchange of vital minerals and helps maintain a proper pH.
Formed Element - Red blood cells, White blood cells, platelets
According to the New health guide,
Red blood cells contain hemoglobin which is a protein that contains iron and are responsible for transporting oxygen and carbon dioxide which is dissolved extracellularly as a bicarbonate ion within the plasma.
White blood cells are tasked with defending the body against bacteria, viruses and parasites. These blood cells can fight disease in various ways. They could either produce antibodies that overpower germs or surround and devour any bacterial presence.
Platelets are the blood clotting element in the blood. The body naturally controls blood loss and it protects itself by sending the platelets to clot blood and consequently prevent bleeding to death.
Another property of the red blood cell is the hemoglobin. Hemoglobin is part of the cytoplasm consisting of a watery solution containing hemoglobin. Hemoglobin binds oxygen to the cell, it is a protein based molecule containing four protein chains. Iron is an essential element to the proper function of hemoglobin.
When the blood is lacking in hemoglobin it is called anemia. According to Addison and Wesley’s Biology 11 anemia is caused by genetic diseases of the blood, production of too few red blood cells and reduced hemoglobin in cells. “The treatment your doctor prescribes for you will depend on the cause of the anemia. For example, treatment for sickle cell anemia is different than treatment for anemia caused by low iron or folic acid intake. Treatment may include changes in foods you eat, taking dietary supplements (like vitamins or iron pills), changing the medicines you are taking, or in more severe forms of anemia, medical procedures such as blood transfusion or surgery.” (Women's health, 2012)
I would just like to point out that non of the videos or pictures found in this blog are my property. They are all things that I found in the making of this project. Any and all information I have either found online or in my Addison Wesley Biology text book.
