cardiac and vascular systems Flashcards
properties of arteries
carry blood away from the heart, thick muscular wall, elastic, contractile. the movement of blood from the beart to the peripheral capillaries includes: elastic and muscular arteries, arterioles.
properties of veins
carry blood from organs and tissues and return it to the heart. thinner walla as blood pressure is lower, larger in diameter, venous valves.
properties of capillary
surrounding muscle fibres, onlt blood vessel which allows exchange across the walls. Continuous capillaroes are the most common and are called continuous because the cells sit closer together. they have a lining made up of endotherlial cells.
cardiac muscle
concentric layers that wrap around the atria. spiral within the walls of the ventricles.
cardiac cells
have myogenic rhythm, no need for nervous stimulation and have pacemaker cells. beats rhythmically, not able to produce prolonged contractions, a property of its membrane potential. must have oxygen at all times, glucose, fatty acids, lactic acid, pyruvic acid, and strictly aerobic.
the function of the pericadium
fibrous sac that encloses the heart, normally contains 5-10ml of liquid, stabilises the position of the heart, prevents the heart from excessive dilation and overfilling with blood, it lubricates the heart preventing friction with the surrounding tissues as it beats, protects the heart from nearby infections from organs like the lungs.
the structure of the pericardium
consists of 2 layers, in between these two layers is the fluid-filled pericardial cavity.
outer layer- fibrous pericardium, made from thick connective tissue, attached to the diaphragm and holds the heart in place, protects from infections.
inne layer-serous pericardium, lubricates your heart, further divided into two more layers: visceral parietal.
right atrium
receives blood from systematic circulation. superior vena cava, inferior vena cava, coronary sinus.
right ventricle
blood travels from right atrium to right ventricle through the tricuspid valve. theres 3 fibrous flaps. the internal surface of the right ventricle contains trabeculae carnae and a moderator band. Blood travels from the ventricles to the pulminary artery via the pulmonary valve.
left atrium
blood from the pulmonary veins, blood moves from the left atrium to the left ventricle via mitral valve.
left ventricle
has thicker walls than the right ventricle, allows left ventricle to develop higher pressures, and pushes through the large systemetic system. blood leaves the left ventricle into the ascending aorta via aortic valve.
Atrioventricular valves
tricuspid (right side) mitral (left side) to prevent backflow of blood from the ventricles into the atria during systole. chordae tendinae and papillary muscles are loose when the ventricles are relaxed. damage of the chodae tendinae causes backflow of blood into the atria
semilunar valves
Pulmonary valve (right side) and aortic valve (left side). prevents the backflow of blood into the ventricles. doesn’t require muscular braces. arterial walls do not contract. as ventricles contract and theres more intraventricular pressure the blood forces the semilunar valves open.
blood supply to the heart
cardiac cells require a reliable supply of oxygen and nutrients.
bloo flows through the chambers of the heart. the heart has its own coronary circulation. this supplies blood to the cardiac tissue. During maximum exertion the demand for O2 rises. blood flow may increase upto nine times then when resting. extensive network for coronary blood vessels.
coronary arteries
they originate at the base of aorta and over the cusp of the aortic valve. blood pressure is at its highest in the systematic circuit. Elastic rebound. the combination of both elevated pressures plus the elastic rebound ensures continuous blood flow. the flow isn’t steady, so it peaks in diastole and ceases in systole.
