i Flashcards
Primary organ of the cardiovascular system
Heart
- It is a four-chambered, hollow, muscular organ that is slightly larger than a man’s closed fist.
- It lies in the anterior medial area of the chest, posterior to the ribcage.
- It is surrounded by a thin fluid-filled sac called the pericardium and its walls have three distinct layers.
- It has two sides, a right and a left.
- It is a double-pump system
Heart
A a medial muscular wall that separates the left and right chambers from each other by partitions
Septa (singular, septum)
A thin fluid-filled sac surrounding the heart
Pericardium
Three layers of the heart
Epicardium, Myocardium, Endocardium
Layer: thin outer layer
* thin, serous (watery) membrane that is continuous with the lining of the pericardium
* covers the heart and attaches to the pericardium
Epicardium
Layer: middle muscle layer
* thick layer of cardiac muscle
* contracts to pump blood into the arteries
Myocardium
Layer: thin inner layer of the heart
* thin layer of epithelial cells that is continuous with the lining of the blood vessels
* lines the interior chambers and valves
Endocardium
- Upper chambers on each side of the heart
- singular (atrium)
- receiving chambers
Atria
- Lower chambers
- pumping or delivering chambers
Ventricles
The valves at the entrance to the ventricles. They are also attached to the walls of the ventricles by thin threads of tissue called chordae tendineae, which keep the valves from flipping back into the atria
Atrioventricular valves (AV)
Chamber: Receives deoxygenated blood from the body via both the superior (upper) vena cava and inferior (lower vena cava) and pumps it into the right ventricle
Right atrium
Chamber: Receives blood from the right atrium and pumps it into the pulmonary artery, which carries it to the lungs to be oxygenated
Right ventricle
Chamber: Receives oxygenated blood from the lungs via the pulmonary veins and pumps it into the left ventricle
Left atrium
Chamber: Receives blood from the left atrium and pumps it into the aorta. The walls of this are nearly three times as thick as those of the right ventricle owing to the force required to pump the blood into the arterial system
Left ventricle
These are valves that exit the ventricles; they are crescent-shaped like a half moon
Semilunar valves
Valves:
* Blood flows from this through the Mitral valve and in the left ventricle
Blood Vessels:
* Oxygenated blood comes from the lungs and enters the heart from the Pulmonary veins
Left atrium
Valves:
* Blood is pumped from this through the Aortic valve and into the aorta
Blood Vessels:
* Oxygenated blood leaves the heart from the Aorta
Left ventricle
Valves:
* Blood flows from this through the Tricuspid valve and into the right ventricle
Blood Vessels:
* Deoxygenated blood enters the heart from the Vena cava (superior and inferior)
Right atrium
Valves:
* Blood is pumped from this through the Pulmonary valve and into the pulmonary artery
Blood Vessels:
* Deoxygenated blood exits the heart through the Pulmonary artery towards the lungs
Right ventricle
The left and right ventricles are surrounded by a large layer of cardiac muscle which allows the pumping mechanism of the heart to exist
* it occurs as the heart beats, pumping blood through a system of blood vessels that carry blood to every part of the body
cardiac cycle
Two phases of the cardiac cycle:
Systole and Diastole
It occurs when the heart contracts to pump blood out. The semilunar valves are open while the atrioventricular valves are closed. The aortic valve allows blood to be pumped from the left ventricle into the aorta. The pulmonary valve allows blood to be pumped from the right ventricle into the pulmonary artery.
Systole
It occurs when the heart relaxes after contraction. The atrioventricular valves open while the semilunar valves are closed. The mitral valve (bicuspid) allows blood to enter from left atrium into the left ventricle. The tricuspid valve allows blood to enter from the right atrium into the right ventricle.
Diastole
What valve is open in systole?
Semilunar valves
What valve is closed in systole?
Atrioventricular valves
What valve is open in diastole?
Atrioventricular valves
What valve is closed in diastole?
Semilunar
What is responsible for the delivery of oxygen and nutrients to all the tissues of the body to maintain their function and homeostasis?
Blood
- It is the movement of blood from the heart to the surrounding tissues and organs, and back to the heart.
- It includes all arteries that carry oxygenated blood from the left ventricle to systemic capillaries, as well as the veins and venules that return deoxygenated blood to the right atrium after flowing through body organs.
Systemic circulation
What is the color of the blood leaving the aorta and flowing through the systemic arteries?
Bright Red
What is the color of the blood as it loses of its oxygen and picks up carbon dioxide?
Dark Red