Human cardiovascular system

HUMAN CARDIOVASCULAR SYSTEM

1. HUMAN CARDIOVASCULAR SYSTEM JAI NARAIN VYAS UNIVERSITY, JODHPUR ASSISTANT PROFESSOR:- ASHWIN SINGH CHOUHAN DEPARTMENT:- PHARMACOLOGY E-mail:- [email protected]

2. HEART ANATOMY The heart weighs between 7 and 15 ounces (200 to 425 grams) and is a little larger than the size of your fist. By the end of a long life, a person’s heart may have beat (expanded and contracted) more than 3.5 billion times. In fact, each day, the average heart beats 100,000 times, pumping about 2,000 gallons (7,571 liters ) of blood. JNVU PHARMACY, JODHPUR

3. JNVU PHARMACY, JODHPUR Your heart is located between your lungs in the middle of your chest, behind and slightly to the left of your breastbone (sternum). A double-layered membrane called the pericardium surrounds your heart like a sac . The outer layer of the pericardium surrounds the roots of your heart’s major blood vessels and is attached by ligaments to your spinal column, diaphragm , and other parts of your body. The inner layer of the pericardium is attached to the heart muscle . A coating of fluid separates the two layers of membrane, letting the heart move as it beats. Your heart has 4 chambers . The upper chambers are called the left and right atria , and the lower chambers are called the left and right ventricles . A wall of muscle called the septum separates the left and right atria and the left and right ventricles. The left ventricle is the largest and strongest chamber in your heart. The left ventricle’s chamber walls are only about a half-inch thick , but they have enough force to push blood through the aortic valve and into your body.

4. FUNCTIONS OF THE CARDIOVASCULAR SYSTEM JNVU PHARMACY, JODHPUR The cardiovascular system has three major functions: transportation of materials, protection from pathogens, and regulation of the body’s homeostasis. TRANSPORTATION: The cardiovascular system transports blood to almost all of the body’s tissues. The blood delivers essential nutrients and oxygen and removes wastes and carbon dioxide to be processed or removed from the body. Hormones are transported throughout the body via the blood’s liquid plasma. PROTECTION: The cardiovascular system protects the body through its white blood cells. White blood cells clean up cellular debris and fight pathogens that have entered the body. Platelets and red blood cells form scabs to seal wounds and prevent pathogens from entering the body and liquids from leaking out.

5. JNVU PHARMACY, JODHPUR Blood also carries antibodies that provide specific immunity to pathogens that the body has previously been exposed to or has been vaccinated against. REGULATION: The cardiovascular system is instrumental in the body’s ability to maintain homeostatic control of several internal conditions. Blood vessels help maintain a stable body temperature by controlling the blood flow to the surface of the skin. Blood vessels near the skin’s surface open during times of overheating to allow hot blood to dump its heat into the body’s surroundings. In the case of hypothermia, these blood vessels constrict to keep blood flowing only to vital organs in the body’s core. Blood also helps balance the body’s pH due to the presence of bicarbonate ions, which act as a buffer solution. Finally, the albumins in blood plasma help to balance the osmotic concentration of the body’s cells by maintaining an isotonic environment.

6. HEART LAYERS JNVU PHARMACY, JODHPUR The wall of the heart is quite thick and is composed of three layers. The endocardium is the inner layer of the heart lining the heart chambers. It is a very smooth, thin layer that serves to reduce friction as the blood passes through the heart chambers. The myocardium is the thick, muscular middle layer of the heart. Contraction of this muscle layer develops the pressure required to pump blood through the blood vessels. The epicardium is the outer layer of the heart. The heart is enclosed within a double-layered pleural sac, called the pericardium. The epicardium is the visceral pericardium, or inner layer of the sac. The outer layer of the sac is the parietal pericardium. Fluid between the two layers of the sac reduces friction as the heart beats.

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8. HEART CHAMBERS JNVU PHARMACY, JODHPUR The heart is divided into four chambers or cavities. There are two atrium , or upper chambers, and two ventricles , or lower chambers. These chambers are divided into right and left sides by walls called the interatrial septum and the interventricular septum. The atrium are the receiving chambers of the heart. Blood returning to the heart via veins first collects in the atrium. The ventricles are the pumping chambers. They have a much thicker myocardium and their contraction ejects blood out of the heart and into the great arteries

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10. JNVU PHARMACY, JODHPUR THE HEART VALVES Four valves regulate blood flow through your heart The tricuspid valve regulates blood flow between the right atrium and right ventricle. The pulmonary valve controls blood flow from the right ventricle into the pulmonary arteries, which carry blood to your lungs to pick up oxygen. The mitral valve lets oxygen-rich blood from your lungs pass from the left atrium into the left ventricle. The aortic valve opens the way for oxygen-rich blood to pass from the left ventricle into the aorta, your body’s largest artery.

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12. JNVU PHARMACY, JODHPUR BLOOD VESSELS The blood vessels are the part of the CVS that carry blood throughout the different parts of the body. These vessels carry blood into all of our organs and tissues, supplying the oxygen and nutrients necessary for our bodies to function properly. There are 3 major types of blood vessels: Arteries – carry blood (rich in oxygen) away from the heart to the body Capillaries – very small blood vessels that allow for exchange of gases (oxygen and carbon dioxide), water, nutrients, and waste products to and from the blood Veins – carry blood (poor in oxygen) back to the heart

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15. JNVU PHARMACY, JODHPUR Arteries Arteries are the blood vessels that carry blood away from the heart. The walls of these vessels are elastic in nature, which allows them to expand and contract as the heart powerfully pumps blood through them. The size of these vessels decreases as they move further and further away from the heart, until they become the smallest vessels – capillaries. The heart has its own set of arteries to supply it with blood called the coronary arteries.The powerful pumping of the heart exerts pressure on the walls of the arteries as blood flows through them, causing them to expand. This rhythmic expansion and contraction of the blood vessels can be felt as the pulse (or heart rate), and it can be measured as blood pressure (BP ). It is important to remember, however, that the force of the blood on the blood vessels is what creates BP.

16. JNVU PHARMACY, JODHPUR Capillaries As the arteries become smaller and smaller, they eventually turn into capillaries – very thin blood vessels. These vessels are thin enough to allow the products carried within the blood to be exchanged with the surrounding tissues. These include nutrients derived from food, oxygen, carbon dioxide, and waste products. As waste products and carbon dioxide collect in the capillaries, many capillaries come together and form larger vessels to transport the blood back to the heart – these larger vessels are the veins.

17. JNVU PHARMACY, JODHPUR Veins collect blood from the capillaries and return it to the heart. Since they are farther away from the heart, the BP in these vessels is much lower compared to arteries. The veins all carry low oxygen ( poor in oxygen ) blood back to the heart, where the cycle can repeat itself. It is important to note that the two most important organs of the body – the heart and the brain – have networks of blood vessels that ensure they are constantly supplied with blood. A constant supply to these organs is crucial for our well-being, and problems with circulation to these organs can cause serious problems, as will be discussed in the next section.

18. The one-way system carries blood to all parts of your body. This process of blood flow within your body is called circulation.  Arteries  carry oxygen-rich blood away from your heart, and  veins  carry oxygen-poor blood back to your heart. In pulmonary circulation , though, the roles are switched. It is the pulmonary artery that brings oxygen-poor blood into your lungs and the pulmonary vein that brings oxygen-rich blood back to your heart. JNVU PHARMACY, JODHPUR

19. JNVU PHARMACY, JODHPUR THE CIRCULATORY SYSTEM The heart and circulatory system make up your cardiovascular system. Your heart works as a pump that pushes blood to the organs, tissues, and cells of your body. Blood delivers oxygen and nutrients to every cell and removes the carbon dioxide and waste products made by those cells. Blood is carried from your heart to the rest of your body through a complex network of arteries, arterioles, and capillaries. Blood is returned to your heart through venules and veins. If all the vessels of this network in your body were laid end-to-end, they would extend for about 60,000 miles (more than 96,500 kilometers ), which is far enough to circle the earth more than twice!

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21. BLOOD FLOW THROUGH THE HEART JNVU PHARMACY, JODHPUR The flow of blood through the heart is very. It progresses through the heart to the lungs, where it receives oxygen then goes back to the heart and then out to the body tissues and parts. The normal process of blood flow is: 1. Deoxygenated blood from all the tissues in the body enters a relaxed right atrium via two large veins called the superior vena cava and inferior vena cava. 2. The right atrium contracts and blood flows through the tricuspid valve into the relaxed right ventricle. 3. The right ventricle then contracts and blood is pumped through the pulmonary valve into the pulmonary artery, which carries it to the lungs for oxygenation. 4. The left atrium receives blood returning to the heart after being oxygenated by the lungs. This blood enters the relaxed left atrium from the four pulmonary veins.

22. JNVU PHARMACY, JODHPUR 5. The left atrium contracts and blood flows through the mitral valve into the relaxed left ventricle. 6. When the left ventricle contracts, the blood is pumped through the aortic valve and into the aorta, the largest artery in the body. The aorta carries blood to all parts of the body. It can be seen that the heart chambers alternate between relaxing, in order to fill, and contracting to push blood forward. The period of time a chamber is relaxed is diastole. The contraction phase is systole.

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24. JNVU PHARMACY, JODHPUR THE CONDUCTION SYSTEM Electrical impulses from your heart muscle (the myocardium) cause your heart to contract. This electrical signal begins in the sinoatrial (SA) node, located at the top of the right atrium. The SA node is sometimes called the heart’s “ natural pacemaker .” An electrical impulse from this natural pacemaker travels through the muscle fibers of the atria and ventricles, causing them to contract. Although the SA node sends electrical impulses at a certain rate, your heart rate may still change depending on physical demands, stress, or hormonal factors

25. CONDUCTION SYSTEM OF THE HEART JNVU PHARMACY, JODHPUR The heart rate is regulated by the autonomic nervous system therefore, there is no voluntary control over the beating of the heart. Special tissue within the heart is responsible for conducting an electrical impulse stimulating the different chambers to contract in the correct order. The path that the impulses travel is as follows The sinoatrial (SA, S-A) node, or pacemaker, is where the electrical impulses begin. From the sinoatrial node, a wave of electricity travels through the atria, causing them to contract, or go into systole. The atrioventricular node is stimulated. This node transfers the stimulation wave to the atrioventricular bundle (formerly called bundle of His). The electrical signal next travels down the bundle branches within the interventricular septum. The Purkinje fibers out in the ventricular myocardium are stimulated, resulting in ventricular systole.

26. JNVU PHARMACY, JODHPUR BEATING OF THE HEART We know that it is the contraction of the heart that pumps blood throughout the body, but what is it that causes these contractions to happen? The heartbeat is created by small electrical impulses that perpetually cause the muscles in the heart to contract. A network of nerve fibers is present between the muscles in the heart, and these fibers act like electrical wires, coordinating the contraction and relaxation of the different chambers. By keeping all of these muscles contracting and relaxing in a coordinated way, the heart creates a wave-like pumping action that efficiently moves blood throughout the body. The steady pumping action of the heart is often described as its ‘rhythm’.

27. JNVU PHARMACY, JODHPUR It is normal for the heart to beat at different rates throughout the day. People may occasionally experience harmless variations in heart rhythm, referred to as palpitations. To contrast, a consistently abnormal heart rhythm is referred to as an arrhythmia. The heart may beat too fast, too slow, or with an irregular pattern. Changes to heart rhythm are caused by irregularities in the transmission of the electrical impulses that cause the heart muscles to contract. An arryhthmia does not necessarily mean that the heart is unhealthy, but some types of arrhythmias are of concern. Syncope (fainting) is associated with some arrhythmias. Arrhythmias must be diagnosed by a physician, often using an electrocardiogram (ECG) or other heart monitoring device.

28. JNVU PHARMACY, JODHPUR The most common arrhythmia is atrial fibrillation, which is characterized by a rapid, irregular heart beat. Atrial fibrillation is caused by abnormal electrical impulses in the upper chambers of the heart (left atrium and right atrium). These abnormal electrical impulses cause the upper chambers to contract very rapidly and irregularly, in comparison to the lower chambers of the heart (left and right ventricles). The pumping action of the heart is therefore uncoordinated, so the heart does not pump blood as efficiently. Atrial fibrillation decreases the heart’s pumping efficiency and increases the risk of blood clot formation in the heart and the arteries. These effects can increase a person’s risk of congestive heart failure, heart attack, and stroke,

29. JNVU PHARMACY, JODHPUR Heart sound HEART SOUND

30. JNVU PHARMACY, JODHPUR BLOOD PRESSURE Blood is the specialized tissue of the human body that supplies nourishment especially oxygen to the cellular elements of the tissues and remove the waste products especially carbon dioxide from the same, there by maintaining the required temperature of the body etc. In performing the above functions, blood exerts some type of pressure upon the walls of the blood vessels which we generally called Blood pressure . It is an important indicator of cardiovascular functioning. It varies with age , sex , race, body weight, fitness levels and several other factors . Generally the most acceptable definition of Blood pressure is - the pressure exerted by circulating blood upon the walls of blood vessels. Blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat , blood pressure varies between a maximum ( systolic ) and a minimum ( diastolic ) pressure.

31. JNVU PHARMACY, JODHPUR Systolic pressure is the maximum blood pressure in an artery when the heart muscle contracts In other words the maximum pressure as the heart beats which averages to about 120 mmHg though the normal range is in between 100-130mmHg). Diastolic pressure is the lowest blood pressure in an artery in the moment between beats when the heart is relaxed. The normal range is in between 60-90, though the average is 80 mmHg. The difference between Systolic and Diastolic pressure, named " Pulse Pressure ", has been gaining interest in the research community. Mean BP is the average pressure throughout the cardiac cycle . Calculated as Diastolic Pressure+1/3Pulse pressure. Av. 96 mmHg ( Normal range 95-100 ) A person’s blood pressure is therefore expressed in terms of the systolic pressure over diastolic pressure and is measured in millimeters of mercury (mmHg), for example 140/90mmHg. Here 140 is the systolic pressure and 90 is the diastolic pressure.

32. JNVU PHARMACY, JODHPUR PROCEDURE FOR MEASURING BP Systemic arterial BP can be measured by two method viz. Direct and indirect method. Direct method involves the introduction of a cannula into an artery and is therefore unsafe, inconvenient, and involves high risk of infection. Therefore, this method is used only for research purposes particularly in measuring BP of Animals, I ndirect method , there are two ways of measuring one through palpation and another auscultatory . The later is more frequently used as it is more reliable. Auscultatory method wasintroduced by Russian Physician Korotkoff in 1905.

33. JNVU PHARMACY, JODHPUR RECORDING BLOOD PRESSURE

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35. JNVU PHARMACY, JODHPUR ELECTROCARDIOGRAPH (ECG)

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37. JNVU PHARMACY, JODHPUR THE CARDIAC CYCLE The cardiac cycle is the sequence of events that occurs when the heart beats. There are two phases of this cycle: Systole (contraction) Diastole (relaxation) I. Systole Systole is the phase in which both ventricles contract. When these two chambers contract, the muscles powerfully push the blood out into the blood vessels moving away from the heart. As noted before, the right ventricle pushes blood to the lungs, while the left ventricle pushes blood into the aorta, before it is distributed to the rest of the body. During this phase, the contractions cause an increase in the pressure within the blood vessels.

38. JNVU PHARMACY, JODHPUR II. Diastole Diastole is the phase in which both ventricles are relaxed. When these two chambers are relaxed, they are refilled with blood from the each atrium, getting new blood to pump out from the heart and into the blood vessels when the cycle begins again. During this phase, no new blood is pumped into the blood vessels, and thus the pressure in the blood vessels is lower than it is during systole. The cycle of systole and diastole phases continues repeating and is called the cardiac cycle. A normal human heart beats around 60-70 times per minute when at rest.

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40. JNVU PHARMACY, JODHPUR JNVU PHARMACY, JODHPUR CARDIAC OUTPUT MEASUREMENT WITH A TRANSPULMONARY THERMODILUTION METHOD

41. DISEASES OF THE CARDIOVASCULAR SYSTEM JNVU PHARMACY, JODHPUR

42. JNVU PHARMACY, JODHPUR CONGENITAL HEART DISEASE This is a general term for some deformities of the heart that have been present since birth. Examples include : Septal defects :  There is a hole between the two chambers of the heart. Obstruction defects : The flow of blood through various chambers of the heart is partially or totally blocked. Cyanotic heart disease : A defect in the heart causes a shortage of oxygen around the body. ARRHYTHMIA Arrhythmia is an irregular heartbeat. There are several ways in which a heartbeat can lose its regular rhythm. These include: tachycardia , when the heart beats too fast. bradycardia , when the heart beats too slowly. premature ventricular contractions, or additional, abnormal beats. fibrillation, when the heartbeat is irregular. .

43. Arrhythmias occur when the electrical impulses in the heart that coordinate the heartbeat do not work properly. These make the heart beat in a way it should not, whether that be too fast, too slowly, or too erratically. Irregular heartbeats are common, and all people experience them. They feel like a fluttering or a racing heart. However, when they change too much or occur because of a damaged or weak heart, they need to be taken more seriously and treated. Arrhythmias can become fatal. MYOCARDIAL INFARCTION This is also known as a heart attack, cardiac infarction, and coronary thrombosis. An interrupted blood flow damages or destroys part of the heart muscle. This is usually caused by a blood clot that develops in one of the coronary arteries and can also occur if an artery suddenly narrows or spasms. JNVU PHARMACY, JODHPUR

44. CORONARY ARTERY DISEASE The coronary arteries supply the heart muscle with nutrients and oxygen by circulating blood. Coronary arteries can become diseased or damaged, usually because of plaque deposits that contain cholesterol. Plaque build-up narrows the coronary arteries, and this causes the heart to receive less oxygen and nutrients . DILATED CARDIOMYOPATHY The heart chambers become dilated as a result of heart muscle weakness and cannot pump blood properly. The most common reason is that not enough oxygen reaches the heart muscle, due to coronary artery disease. This usually affects the left ventricle . JNVU PHARMACY, JODHPUR

45. HEART FAILURE Also known as congestive heart failure, heart failure occurs when the heart does not pump blood around the body efficiently. The left or right side of the heart might be affected. Rarely, both sides are. Coronary artery disease or high blood pressure can, over time, leave the heart too stiff or weak to fill and pump properly . HYPERTROPHIC CARDIOMYOPATHY This is a genetic disorder in which the wall of the left ventricle thickens, making it harder for blood to be pumped out of the heart. This is the leading cause of sudden death in athletes. A parent with hypertrophic cardiomyopathy has a 50 percent chance of passing the disorder on to their children. JNVU PHARMACY, JODHPUR

46. MITRAL REGURGITATION Also known as mitral valve regurgitation, mitral insufficiency, or mitral incompetence, this occurs when the mitral valve in the heart does not close tightly enough. This allows blood to flow back into the heart when it should leave. As a result, blood cannot move through the heart or the body efficiently. People with this type of heart condition often feel tired and out of breath . MITRAL VALVE PROLAPSE The valve between the left atrium and left ventricle does not fully close, it bulges upwards, or back into the atrium. In most people, the condition is not life-threatening, and no treatment is required. Some people, especially if the condition is marked by mitral regurgitation, may require treatment . JNVU PHARMACY, JODHPUR

47. PULMONARY STENOSIS It becomes hard for the heart to pump blood from the right ventricle into the pulmonary artery because the pulmonary valve is too tight. The right ventricle has to work harder to overcome the obstruction. An infant with severe stenosis can turn blue. Older children will generally have no symptoms. Treatment is needed if the pressure in the right ventricle is too high, and a balloon valvuloplasty or open-heart surgery may be performed JNVU PHARMACY, JODHPUR

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