The On The Dissection Board

The four valves of the heart are the tricuspid valve, the pulmonic valve, the mitral valve, and the aortic valve. The tricuspid valve is located between the right atrium and the right ventricle. It is responsible for allowing blood to flow from the atrium to the ventricle, preventing backflow of blood into the atrium. The pulmonic valve is located between the pulmonary arteries and the right ventricle and is responsible for allowing blood flow from the heart to the lungs. The mitral valve is found between the left atrium and the left ventricle, which allow blood to flow from the left atrium into the left ventricle preventing backflow of blood back into the left atrium. The aortic valve is found between the aorta and the left ventricle and allows blood to flow to the aorta and throughout the body.

34. Why are arteries sometimes called the resistance vessels? More pressure is required to push blood through a constricted vessel than through a dilated one. The force opposing blood flow is called resistance (R) , and arterioles are therefore called resistance vessels

In a normal human being the heart correctly functions by the blood first entering through the right atrium from the superior and inferior vena cava. This blood flow continues through the right atrioventricular valve into the right ventricle. The right ventricle contracts forcing the pulmonary valve to open leading blood flow through the pulmonary valve and into the pulmonary trunk. Blood is then distributed from the right and left pulmonary arteries to the lungs, where carbon dioxide is unloaded and oxygen is loaded into the blood. The blood is returned from the lungs to the left

When the left atrium is filled with blood, the heart contracts and the blood passes through the bicuspid valve and into the left ventricle.

Starting about an inch posterior to the clitellum and just to the left of center. Pull apart the edges of the cut. Using tweezers and your probe, break the septa so that you can peel back the body wall. Peel back the body wall on both sides of the cut and pin it down.

Describe what the left and right beakers in the experiment correspond to in the human heart

within the heart: the blood streams easily. In the event that the heart is strange because of specific sorts of

At some point in the wall of the right atrium neighboring itself to the sinus venarum at the junction where the superior vena cava enters the right atrium, the SA node sits quietly. After sitting on a lab stool hunched over the clean, ebony tables, meticulously carving and stitching the heart, I had finally reached the point of the anatomy lesson that I had been waiting years to do.

Firstly the kidney parts such as the ureter, renal artery and renal vein were examined. Next kidney got cut perpendicular to the long axis to be able to reveal the internal structure and parts. This kidney was cut open by a medical grade scalpel and scissor.

An understanding of the circulation of blood through the heart might help the reader to get an better understanding of how the different parts of the heart relate. It helps to think of all the blood vessels in the body as a huge, sophisticated railway network, where essentially all the blood in the veins throughout the body ends up in the vena cava, the railway end station. The superior vena cava receives blood from the upper part of the body, whereas the inferior vena cava receives blood from the lower part of the body. As the blood fills up in the RA, the increased pressure eventually makes the tricuspid valve shut open, allowing deoxygenated blood to enter the RV. As the deoxygenated blood flows into the RV, the pressure in front of the

Oxygenated red blood cells enters the heart through pulmonary veins and goes into the left atrium. The oxygenated blood then goes through the mitral valve and into the left ventricle, mitral valve is activated, therefore it closes shut to prevent backflow of blood. The thick muscular wall contracts forcing blood out through the Aorta, the semilunar valves is activated so blood does not flow back into the left ventricle. The oxygenated blood is carried to the body.

“During the diastole phase, the atria and ventricles are relaxed and the atrioventricular valves are open. De-oxygenated blood from the superior and inferior vena cavae flows into the right atrium. The open atrioventricular valves allow blood to pass through to the ventricles. The SA nodes contracts triggering the atria to contract. The right atrium empties its contents into the right ventricle. The tricuspid valve prevents the blood from flowing back into the right atrium.”(About.com)

The first part of the dissection was a thorough examination of the cardiovascular system. My first task was to explore the areas of the fetal pig heart along with the sheep heart. I found several similarities and differences between the two hearts. I found that the fetal pig heart and the sheep heart did not show any significant differences. However, one difference I noted was that the sheep heart was much larger, making it closer to the size of a human heart compared to the fetal pig heart. Another noticeable difference was that the sheep heart had an excessive amount of fatty tissue surrounding the outer wall of the heart. Fatty tissue could not be seen on the fetal pig heart. I was able to find many similarities between the two animal hearts.

Blood from the left side of the mitral and tricuspid valve open flows in the right ventricle and through its ventricle.

The heart is a hollow, muscular organ of the middle mediastinum orientated obliquely in the chest, divided into four chambers by an atrioventricular constriction and the inter-ventricular septum. Surface grooves indicate these divisions: the atria are separated from the ventricles by the coronary sulcus (the atrioventricular groove) with a hiatus anteriorly at the root of the pulmonary artery (PA). The atria are separated posteriorly by the inter-atrial groove though this is scarcely marked, and anteriorly this is hidden by the pulmonary artery and aorta. The ventricles are separated posteriorly by the posterior longitudinal sulcus on the diaphragmatic surface and anteriorly by the anterior longitudinal sulcus on the sternocostal surface, extending from the base of the heart to a notch, the incisura apices cordis on the acute margin of the heart just to the right of the apex [46].