circulatory/cardiovascular system 1 Flashcards
Valves
Valves are located in the heart and veins. They ensure that circulation of blood occurs in only one direction by preventing backflow.
Artery
The artery distributes oxygen-rich blood from your heart to your capillaries. The artery is made up of three layers: the tunica intima, the tunica media, and tunica externa. It is made up of thick walls and a narrow lumen. It has no valves.
Tunica intima
The tunica intima is the innermost layer that lines the lumen of all blood vessels to reduce friction.
Tunica media
The tunica media is the middle and thickest layer that is made up of muscle cells and elastic fibers.
Tunica externa
The tunica externa is the outermost and toughest layer made of collagen fibers that protect the blood vessels and anchor it to surrounding structures.
Vasoconstriction versus vasodilation
Vasoconstriction is when the muscles inside blood vessels tighten to make the space inside them smaller. Vasodilation is when the muscles inside blood vessels relax to make the space inside them larger.
Arterioles
Arterioles are smaller forms of arteries that supply blood to organs, limbs, etc. They also have a higher muscle density.
Atria
The atria is the upper chambers of the heart.
Veins
Veins transport blood from the capillaries and return it to the heart. They experience lower blood pressure. They are made up of three layers: tunica externa, tunica media, and tunica intima. They are made up of thin walls and a wide lumen. They do contain valves.
How is blood flow ensured?
Blood flow is ensured in 2 ways. The first way is from skeletal muscles exerting pressure to the veins which squeezes the veins like a pump. The second way is from valves that are found within veins, preventing backflow.
What does blood consist of?
Blood consists of a plasma, red blood cells, white blood cells, and platelets.
Plasma
Plasma is the liquid portion within blood that carries proteins, hormones, carbon dioxide, glucose, vitamins, and minerals.
Red blood cells versus white blood cells
Red blood cells transport oxygen, while white blood cells defend the body against disease.
Platelets
Platelets are involved in clotting blood when blood vessels break.
Capillaries
Capillaries have permeable walls that allow exchange of materials between tissue cells and blood. Blood flow is slowest in the capillaries, to allow time for this exchange. Capillaries are one-cell thick and contain no valves.
Pulmonary versus systemic circulation
Pulmonary circulation (right side of the heart) transports deoxygenated blood from the heart to the lungs. Systemic circulation (left side of the heart) carries oxygenated blood from the heart to the rest of the body.
Aorta
The aorta is the main and biggest artery that carries oxygenated blood to all parts of the body from the left ventricle. Its elastic property is helpful when its walls return to their normal shape because the recoil propels the blood forward, maintaining blood pressure.
Superior versus inferior vena cava
The superior vena cava brings deoxygenated blood from the upper body to the right atrium. The inferior vena cava brings deoxygenated blood from the lower body to the right atrium.
Pulmonary artery and veins
The pulmonary artery and veins brings oxygenated blood from the lungs to the left atrium.
Right versus left atrioventricular valve
The right atrioventricular valve prevents backflow of blood into the right atrium when the right ventricle is contracting. The left atrioventricular valve prevents backflow of blood into the left atrium when the left ventricle is contracting.
Pulmonary versus aortic semilunar valve
The pulmonary semilunar valve guards the opening of the pulmonary artery from the right ventricle to prevent backflow of blood. The aortic semilunar valve guards the opening to the aorta from the left ventricle to prevent backflow of blood.
