Question

Describe the structure of the human heart; explain the movement of blood flow through the heart, lungs, and body. Your answer should be specific.

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Answer 1

Structure of human Heart :-
- The human heart is a four-chambered muscular organ, shaped and sized roughly like a man's closed fist with two-thirds of the mass to the left of midline.
-The heart is enclosed in a pericardial sac that is lined with the parietal layers of a serous membrane The visceral layer of the serous membrane forms the epicardium .
-Three layers of tissue form the heart wall. The outer layer of the heart wall is the epicardium, the middle layer is the myocardium and the inner layer is the endocardium .
- The internal cavity of the heart is divided into four chambers:Right atrium,Right ventricle,Left atrium,Left ventricle.

The two atria are thin-walled chambers that receive blood from the veins. The two ventricles are thick-walled chambers that forcefully pump blood out of the heart. Differences in thickness of the heart chamber walls are due to variations in the amount of myocardium present, which reflects the amount of force each chamber is required to generate.

-The right atrium receives deoxygenated blood from systemic veins; the left atrium receives oxygenated blood from the pulmonary veins.
-Pumps need a set of valves to keep the fluid flowing in one direction and the heart is no exception. The heart has two types of valves that keep the blood flowing in the correct direction. The valves between the atria and ventricles are called atrioventricular valves (also called cuspid valves), while those at the bases of the large vessels leaving the ventricles are called swmilunar valve .
The right atrioventricular valve is the tricuspid valve. The left atrioventricular valve is the bicuspid, or mitral, valve. The valve between the right ventricle and pulmonary trunk is the pulmonary semilunar valve. The valve between the left ventricle and the aorta is the aortic semilunar valve.

Movement of blood flow through heart,lungs and body :-

Aorta-Carries the blood from the left ventricle to the rest of the body.
Aortic Valve-Allows the blood to go from the Left ventricle to the aorta. It separates them.
Apex-Bottom point of the heart.
Arteries-Bring blood away from the heart.
Atria-Located the top two chambers of the heart. These are the receiving chambers.
Auricles-Outer parts of the heart. They indicate the atria and look like elephant ears.
Bicuspid Valve-Allows the blood to travel from the left atrium to the left ventricle.
Chambers-Left Atrium and Ventricle, Right Atrium and Ventricle
Chordae Tendinae-Connects the valve to the papillary muscle
Inferior Vena Cava-Brings de-oxygenated blood back from the rest of the body to the heart
Interventricular Septum-Muscle that separates the ventricles
Left Atrium-The receiving chamber on the top left side. receives from the Pulmonary vein.
Left Ventricle-The bottom left ventricle that pumps the blood out through the aorta and to the rest of the body.
Moderator Band-This is found in the right side and it is there to hold the ventricle walls together.
Papillary Muscle-Found in the ventricular walls-- they contract to allow movement of the valves.
Pulmonary Arteries-This carries the blood from the heart to the lungs from the Right Ventricle
Pulmonary Valve-This separates the Right Ventricle and Pulmonary Artery
Pulmonary Veins-These carry the blood from the lungs to the left ventricle.
Right Atrium-This is where the process begins. It receives de-oxygenated blood from the rest of the body through the vena cava.
Tri-cuspid Valve-This allows the blood to pass from the Right Atrium to the Right ventricle.
Trabeculae Carnae-Rough surface that prevents the walls of the heart muscle to suction together.
Superior Vena Cava-Brings blood to the Right Atrium from the rest of the body.
Veins-These carry blood to the heart