Anatomy of The Heart
Body contains three types of muscles. The first, called the skeletal muscle, the muscle is the type usually think when we remember the muscles. skeletal muscle to ensure mobility and movement, the biceps muscle to move the arms or quadriceps muscles to move our legs. These muscles operate because of the conscious control of our brain. Arm does not automatically take a free kick until you ask him to do (even if said Dr P freehand shots do not always work as expected).
The second type of muscle called smooth muscle. smooth muscles tend to perform their tasks automatically, without conscious thought on our part. Do not tell them what to do, do it yourself, under the control of the autonomic nervous system (ANS). muscle surrounding arteries to constrict or expand their muscles are smooth. intestinal muscles, which, when pressed food (a process called peristalsis) are made of smooth muscle.
The latter type of muscle called the myocardium and located in the heart. heart muscle have their own electricity supply, and "fire" alone, without stimulation.
It is close to the heart muscle (myocardium) of the left ventricle of the dog. It is thick, because the heart of the dog must spend their lives pumping blood to all body cells. Later, when we speak of cardiomyopathy is a muscle that is affected.
As the beating heart of its own? This is because each cell of the electricity supply own heart. For a little more simple and complicated story that has to do with the heart cells how to behave, or excretion of potassium, sodium and calcium ions. When sodium and calcium is pumped from the heart cells, potassium is pumped in. This creates an imbalance that ultimately in the balance, more sodium and potassium ions outside and inside cells heart. This creates a "positive" for the outside of the heart, a heart cell is now a "polarization" (remember these words when considering ECG).
Council wishes to eventually restore the balance of sodium, calcium and potassium. So, the opposite occurs. Potassium moves from the rush of sodium and calcium in the cell is depolarized today and will stay that way for the positive charge outside the cell reaches the threshold, and again that the flow is reversed. Whenever there is a reverse flow, it generates an electric spark, the heart racing. This is an electrical spark, which causes the heart cells to contract and the heart rate.
Although their pace, heart electrical activity in each cell must be coordinated if the four chambers of the heart (atria and ventricles) are pumping enough blood in the right direction. Later, when we speak of the ECG, it is the electrical conductivity is applicable.
At the beginning of the right atrium is the anatomical structure called the sinoatrial node (SA Node). This is an area of myocardial infarction, which originate in a coordinated heartbeat. When it fires from the SA node sends electrical impulses (son bringing these pulses are called perkinje fiber) for both atria, causing them to contract as soon as possible. One of the signals from the sinus node, also stimulates the atrioventricular node (AV node) located at the bottom of the right atrium. Stimulation of node stimulates nerve fibers that surround the ventricles, causing them to contract a rhythmically. There are other factors, including hormones and other parts of the nervous system.
Package atrioventricular (AV package) is also known as a package in honor of her husband, who discovered it. The heart beats a dog or a cat about two times per second, should trigger the nodes to stay if everything is coordinated. Since the SA node fires only takes 0.22 seconds for the ventricles to contract.
SA node is called the pacemaker because it depolarizes faster than any other group of cells in the heart and makes it faster on the heart in its entirety. If for some reason stops beating sinus node, AV node, which, with the highest rate of depolarization, would be a pacemaker. If no AV node, AV package will take over. If not, the fibers begin Perkinje heartbeat, and if not, as well as groups of cells in another location in the heart starts beating. However, farther from the center gets a normal amount and rate of heartbeat, pump less blood and replaced it and eventually can no longer sustain life.
in the normal heart rhythm, known as arrhythmias, are a common problem in heart disease. Cardiac arrhythmias may be small and insignificant, or serious and potentially fatal. There are many different types of arrhythmias, including:
- Tachycardia-heart rate very quickly. If the heart beats too fast will not spend much time in diastole. Therefore, not enough heart ventricles fill with blood, so the heart does not pump enough blood to the cells. In addition, lack of time causes the heart muscle during diastole itself (myocardium) is suffering because it is in diastole as blood flows through the coronary arteries to the heart muscle.
- Bradycardia, abnormally slow heartbeat. If the heart beats too slowly lowers blood pressure and does not generate enough blood cells. An early symptom is called syncope, which is the same as coming out and becomes unconscious.
- Heart block occurs when the electrical impulse has difficulty passing through the AV node.
- Atrial fibrillation, when the atria contract irregularly and blood does not flow with them effectively
- Ventricular fibrillation-ventricular If the contract is invalid and ineffective manner, a condition which leads rapidly to death unless corrected. He is a man of heart attack and needs defribillator to solve the problem. People who have serious cardiac arrhythmias can sometimes have an artificial pacemaker implanted in the chest or abdomen. This battery powered device provides a rhythmic pulse electrical center or on a constant basis, or only when the natural pacemaker temporarily unable to maintain normal.
You can learn more about the sinus node and AV node in the ECG monitor section, so try to keep their jobs in the memory.
Cavities of The Heart (Atria and Ventricles)
More normal mammalian heart has four chambers (also four birds, reptiles have three.) two lower chambers are called atria, are called ventricles. Diagrams at the top of this page describes the flow of blood through the chambers. Let's see what are the valve chambers and similar really. Click here to see models on the top of the page if you want.
Here autopsy (as well as those at autopsy) pictures showing how they look in the reality of these structures. They are tastefully done and it should not bother you. It is obvious from these pictures that the actual anatomy is much more complicated than drawing pictures. We will focus on the left ventricle and mitral valve, because it is the heart area, causing the most problems as dogs age. We will monitor the flow of blood from the left atrium through the mitral valve and left ventricle.
Before even getting to the heart, is a layer called the pericardium, which surrounds it. In some diseases, the liquid can be accumulated in the outer layer and the actual heart muscle. This is the pericardium of a normal ferret. Fat at heart is normal.
This photo shows mainly in the left ventricle of a dog (the heart of hearts that you saw at the beginning of the page). Looking into the chamber of the left ventricle. Note the thickness of the myocardium (heart muscle) in the left ventricle, with the smooth inner lining of the lower house in the center of the image. Flooring should be smooth and relatively friction-free red blood cells to flow through is not achieved quickly and cracked or bleeding started. hemostatic metal tip (see arrow), barely protruding from the left (no display) through the mitral valve and left ventricle. This is the normal direction of blood flow, as is currently the atrium and left ventricle.
Take a closer look at the mitral valve. Haemostatic walked a little farther through the mitral valve in this table. Moreover, the left atrium is not displayed. White thread-like structures strings tendon. As blood flows through the tendon of the mitral valve mitigate these channels, because there is no pressure on them. The left ventricle contracts a strong desire to get blood into the aorta and the rest of the body. This pressure pushes the mitral valve, which are already closed, because we do not want the blood flowing back into the left atrium. These are the chains that hold the tendon mitral valve closed. normal mitral valve can withstand the pressure, patients may not be.
As can be seen even closer to the mitral valve leaflets clearly (we removed a hemostat so that you can see the bottom of the valve now). arrow Back to normal record, the arrow at the bottom of the poster in bold and shriveled. This folder called endocardiosis thickened (more on this disease in the section, when we learn about chronic atrioventricular valve). This thickening does not allow the valve to close completely, and the blood flows back into the left atrium to left ventricle contracts. Since there is a large pressure difference (pressure gradient) between the atrium and left ventricle, which can have serious consequences. This is turbulent blood regurgitating, and is the source of a heart murmur heard with this disease. If the leak is significant pressure will result in the left atrium to enlarge (you can see in the picture), the possibility that pressure prevents the flow of blood from the pulmonary vein. If the blood in the pulmonary veins is in the process of high pressure in the left atrium, pulmonary vein plasma would leak from the capillaries and fill the lungs (cysts) of liquids. It is also known as pulmonary edema, and is "congested" in congestive heart failure. We will go into further detail because it is an essential element of the atrioventricular valve and chronic congestive heart failure.
There are many other structures in the thorax (chest) in addition to the heart and lungs. Next image autopsy of a dog lying on the right side of his head to the left. We will look into the chest, the chest just before the abdomen.
Before the autopsy can show you get an image oriented. The dog is on the right side and head to the left. Vertical white spots on the line to the section of the chest radiograph will be watching the autopsy photos to follow. White fire running in the back of the inferior vena cava (PVC), which is difficult to see. Use this breakthrough information purposes only, if you look at the actual pictures below.
On the right is a membrane (D) Breathing muscle. It separates the left side of the diaphragm chest from the abdomen on the right side (liver and stomach is located just behind the iris). Posterior vena cava (PVC) is presented as a horizontal structure blue at the bottom of the image that passes through the membrane. That is fine because it is designed to return almost all the blood from the rear of the body to the heart.
Tall structure rose horizontally above the vena cava posterior esophagus (E) which passes through the membrane and into the stomach to the diaphragm on the right. You can see one of the posterior lobe of the lung above and left of the esophagus. If you look closely, you can also see white streaks horizontally along the esophagus (vertical arrow). If you look even closer you will see a large white structure horizontally above the esophagus (horizontal arrow) - integrated in the aortic tissue protection.
This is the same image as before, just look down, rather than later. Rejoice with a dog on his back, the diaphragm (D) is at the base. The structures are labeled the same. Information on how much lung is visualized. Look at the large veins of the lobes of the lung in the upper right corner. Posterior vena cava (PVC), it is clear how the vertical membrane at the bottom of the image and between the right atrium at the top of the image. On either side are the lobes of the lung inferior vena cava and then into the esophagus (E), and aortic white (a). Remember, this raises the lungs. Consider the congestion of the place is when the lungs are full of air you breathe. In fact, the positive and negative thoracic pressure that occurs when we breathe have an impact on how the flow of blood.
Now, away from the membrane and the heart is closer to the side view, head to the left. Heart blue structure above. Pericardium (lining of the heart) is still in the heart, it is not as obvious as one might think. The right atrium can not be displayed, because the heart is covered with pericardium. You can see the posterior vena cava (PVC) on the right as it enters the right atrium. You can also see the front of the vena cava (AVC on the left and enter the right atrium. You can also see how the nerve horizontally on top of each vena cava.
Normal functioning of the heart has to work in optimal conditions, instantly able to adapt to the changing needs of the organization. To all this must work in harmony:
- The blood vessels of the heart to normal. The problem here (atherosclerosis) is a disease generally affects humanoids, not animals. When these blood vessels do not supply the heart with adequate blood flow, myocardial infarction (MI) occurs. This means that a portion of heart muscle dies from lack of blood supply.
- Electrical conduction system must function in a flow of blood in a coordinated manner through the heart chambers effectively. If the problem is so serious that a heart attack can occur. In this state, the heart requires an external electrical load (defribillator) for the shock back into normal rhythm.
- All heart valves are working optimally so that blood can flow in the right direction and in sufficient quantity. Mitral regurgitation causes blood to leak into the wrong room. The disorder causes blood disorders that are received by the stethoscope as a murmur. If the problem is sufficiently severe, can lead to heart failure. Cavities of the heart and muscles must be of sufficient size for optimal blood flow. also, a partition separating the right heart of the heart must be left intact. If not, blood can flow directly from one cell to another, without the normal route through the lungs. The enlargement of the heart leads to dilated cardiomyopathy, which is the heart muscle is too weak to overcome the forces to provide sufficient blood cells. Ventricle, which is too muscular, called hypertrophic cardiomyopathy, leading to the size of the ventricular chamber is too small to fill enough blood to the body's needs.
- Arterial and venous systems must be able to contract and expand, so that the appropriate blood pressure, and maintained so that all cells of the body to get adequate blood flow.
- Cardiovascular Care is a miracle. This series of pumps and pipes are literally unable to provide the billions of cells in the body of their basic needs, and it is in an ever-changing needs.