Cardiovascular Anatomy Flashcards

Question

Semi-lunar valves

Answer 1

Pulmonary and aortic Outlet valves When blood pools in them it gives them strength to not allow the blood to move back into the ventricle where it came from

Answer 2

Found between the right ventricle and the pulmonary artery

Answer 3

Found between the left ventricle and the aorta

Answer 4

Left ventricle : Right ventricle | 3 : 1

Answer 5

Left ventricle : Right ventricle | 5 : 1

Answer 6

Deoxygenated blood enters the right atrium through the inferior and superior vena cava Dexoygenated blood pools in the right atrium until a pressure gradient is reached, when the tricuspid inlet valve opens to allow blood into the right ventricle Deoxygenated blood pools in the right ventricle until a pressure gradient is reached, when the pulmonary outlet valve opens to allow blood to be pushed through the pulmonary arteries into the lungs Oxygenated blood returns from the lungs via the pulmonary veins and enters the left atrium where it pools until a pressure gradient is reached The mitral inlet valve opens allowing the blood to flow from the left atrium to the left ventricle Oxygenated blood pools in the left ventricle until a pressure gradient is reached strong enough to open the aortic outlet valve and push the blood into the aorta to be distributed around the systemic circuit

Answer 7

Formed mainly by the right atrium

Answer 8

Formed mainly by the right ventricle

Answer 9

Formed mainly by the left ventricle

Answer 10

Apex (bottom) points inferiorly, anteriorly and to the left | About 1/3 of the heart lies to the right of the midline of the body and about 2/3 to the left

Answer 11

The pericardium is a double walled bag made up of the parietal and visceral pericardium with a pericardial space in between filled with serous fluid and encased in fibrous pericardium for protection Pericardium layers are made of simple squamous epithelium

Answer 12

Two complete fibrous rings surround the mitral and aortic valve An incomplete fibrous ring surrounds the tricuspid valve No fibrous ring surrounds the pulmonary valve Fatty connective tissue is present in areas where the fibrous skeleton is incomplete It has two functions: to support and maintain the structural integrity of the heart and to act as an electrical insulator

Answer 13

The SA node and the AV node

Answer 14

Sinoatrial node Sits at the top of the right atrium Conducts electrical impulse slowly at 0.5 m/s Purpose is to induce atrial contraction

Answer 15

Atrioventricular node Sits in the middle of the two ventricles at the top in a gap in the fibrous skeleton Conducts electrical impulse from the SA node at a very slow speed of 0.05 m/s to cause a delay of 100 msec between the SA and AV nodes

Answer 16

Atrioventricular bundle of His Stalk of conduction fibres joining the AV node and connecting it to Purkinje fibres Conducts electrical impulse from the AV node at a fast speed of 5 m/s Results in systole and even ventricular contraction

Answer 17

Electrical conduction fibres extending from the AV bundle of His to around the left and right ventricles to induce even contraction across the whole ventricle

Answer 18

The left ventricle sustains 5x more pressure than the right ventricle because of the amount of resistance that needs to be overcome in the aorta to push blood out and the left ventricle has to pump blood all the way around the systemic circuit whereas the right ventricle just has to pump to the lungs To strengthen the heart under this much pressure the wall is thicker and ensures more force of contraction

Answer 19

``` Ventricular filling Atrial contraction Isovolumetric contraction Ventricular ejection Isovolumetric ventricular relaxation ```

Answer 20

Pressure in the ventricle drops below the pressure in the atrium Mitral valve opens, blood enters the ventricle down the pressure gradient Ventricle fills to about 80% capacity during this phase

Answer 21

Left atrium contracts to complete ventricular filling | Small rise in atrial pressure

Answer 22

No change in volume of blood in the ventricle Systole Ventricle begins to contract, lifting the blood back towards the atrium and closing the mitral valve Ventricular pressure is still below aortic pressure so the aortic valve remains closed

Answer 23

Systole continuation Ventricular pressure has reached a peak where it is now higher than the pressure in the aorta, setting up a pressure gradient where blood can flow from high to low and allowing the aortic valve to open Blood is ejected into the aorta so fast that pressure continues to rise in both the ventricle and aorta but both decrease after a certain point

Answer 24

No change in volume of blood in the ventricle Relaxation - diastole Ventricular pressure drops, reversing flow in the aorta due to the changed pressure gradient and causing the aortic valve to close, preventing blood from reentering the ventricle The mitral valve also remains closed because the ventricular pressure is still higher than atrial pressure

Answer 25

The atrial muscle layer is thin so can't withstand too high a pressure There are no valves between the left atrium and the pulmonary veins and so there is nothing to prevent backflow of blood into the pulmonary veins which might occur if the pressure gets too high

Answer 26

The pressure is so high in the ventricle that the speed that is ejects blood into the aorta is faster than it can run-off into the distributing arteries Because the ventricle is still contracting, it increases in pressure as the resistance of the aorta and other distributing arteries prevents free blood flow When the rate of ejection falls below the rate of run-off, both aortic and ventricular pressure drops

Answer 27

The first heart sound (lub) is caused by the turbulence of blood trying to flow back into the atrium where the pressure is lower and hitting the now closed mitral valve flaps The second heart sound (dub) is caused by the turbulence of blood trying to flow back into the ventricle from the aorta when ventricular pressure drops and hitting the now closed aortic valve

Answer 28

Chordae tendinae are fibres attached to the mitral and tricuspid valves that hold the valves shut to prevent backflow from the ventricles to the atria The cusps of the semi-lunar valves are designed to allow blood to pool. When blood tries to backflow from the atria back to the pulmonary circuit, it collects in these cusps like water in a pocket, strengthening the valve. Semi-lunar valves don't need chordae tendinae to keep them shut as they are designed to do it naturally

Answer 29

During ventricular filling, aortic pressure starts at about 100 mmHg and slowly decreases By the time isovolumetric relaxation is complete, the aortic pressure is at 80 mmHg The aortic pressure has now dropped below the ventricular pressure but rises with it during ventricular ejection. It reaches just under 120 mmHg (the peak pressure of the left ventricle) and falls with it When the pressure of the ventricle drops below the pressure of the aorta again (about 100 mmHg) isovolumetric relaxation starts During isovolumetric relaxation the aortic pressure increases slightly (to about 105 mmHg) Aortic pressure then slowly decreases again through ventricular filling, atrial contraction and isovolumetric contraction

Answer 30

During ventricular filling, the pressure of the ventricle is lower than the left atrial pressure (less than 4 mmHg) The ventricular pressure rises very slightly during atrial contraction but is still less than the atrial pressure Ventricular pressure increases rapidly, overtaking the atrial pressure and starting isovolumetric contraction. It continues to rise rapidly during isovolumetric contraction until it surpasses the aortic pressure (around 80 mmHg) and continues to rise steeply until about halfway through the ventricular ejection phase until it reaches its peak of 120 mmHg Ventricular pressure falls quickly after reaching its peak, falling below aortic pressure at the beginning of isovolumetric relaxation (about 100 mmHg) and falling below the atrial pressure at the end of isovolumetric relaxation (around 5 mmHg)

Answer 31

Atrial pressure in the ventricular filling stage is just above the ventricular pressure in order to keep the mitral valve open - around 4 mmHg During atrial contraction, the pressure rises very slightly to about 5 mmHg and then drops again as isovolumetric contraction starts and the ventricular pressure rises Atrial pressure is at its lowest during the start of ventricular ejection but begins to rise during this stage as blood returns from the lungs and begins to pool in the atria again By the end of isovolumetric relaxation, atrial pressure is at its peak (around 5 mmHg) and surpasses the dropping ventricular pressure as ventricular filling starts again

Answer 32

The mitral valve is open during ventricular filling and atrial contraction as the pressure of the atria is above the pressure of the ventricle allowing blood to flow down the pressure gradient to collect in the ventricle The mitral valve closes at the start of isovolumetric contraction to increase the pressure in the ventricle and stays closed through ventricular ejection (to prevent backflow into the atrium) and isovolumetric relaxation (to prevent blood from entrering from the atrium prematurely) The mitral valve opens again at the start of ventricular filling when the atrial pressure surpasses the ventricular pressure The aortic valve is closed during ventricular filling because the ventricular pressure is lower than the aortic pressure. It doesn't open until the end of isovolumetric contraction when the ventricular pressure surpasses the aortic pressure. The aortic valve stays open throughout ventricular ejection to allow all the blood in the ventricle into the systemic circuit. It closes again at the start of isovolumetric relaxation when the ventricular pressure drops below aortic pressure to stop backflow of blood into the ventricle from the aorta.

Answer 33

Very large arteries near the heart which have elastic walls Expand during systole to store blood leaving the ventricle During diastole, push the blood out of the arterial tree by elastic recoil Smooth the pulsatile flow of blood leaving the ventricle Many thin sheets of elastin in the middle tunic

Answer 34

Distribute blood around the body at high pressure and lungs at medium pressure Rate of blood flow is adjusted by vasoconstriction and vasodilation Small change in radius has large effect on flow rate Many layers of circular smooth muscle wrapped around the vessel in the middle tunic

Answer 35

Controls blood flow to capillary beds Thicker muscular wall relative to their size than any other blood vessel Greatest pressure drop and greatest flow resistance occurs here Between one and three layers of circular smooth muscle wrapped around the vessel in the middle tunic

Answer 36

Tiny, thin walled vessels that allow gas, nutrient and waste exchange between blood and surrounding tissue fluid Slow blood flow Leaky vessels allowing plasma to escape Just wide enough to admit one red blood cell at a time Single layer of endothelium with an external basement membrane. No smooth muscle, therefore no ability to vasoconstrict, no connective tissue

Answer 37

Low pressure vessels that drain capillary beds Site of extravasation of leukocytes Small venules have usual epithelium plus some connective tissue Larger venules also have some smooth muscle

Answer 38

Thin walled, low pressure vessels that drain blood back to the atria Thin, soft and compliant walls Small change in venous blood pressure causes a large change in venous volume Act as blood reservoirs Less muscle and connective tissue than arteries but otherwise similar Larger veins have valves which prevent backflow

Answer 39

Arising from the aorta downstream of the aortic valve Supply the myocardium Small muscular arteries

Answer 40

Total peripheral resistance | Mean arterial blood pressure

Answer 41

Artery - artery junctions

Answer 42

Drain deoxgenated blood away from myocardium to the right atrium

Answer 43

1 - 2 mmHg

Answer 44

Cause often unable to be identified Viral infection in many cases Infected muscle fibres attacked by lymphocytes, killing some and leaving others damaged and slow to contract Left ventricle most affected because of high pressure Left ventricle dilates, chamber enlarges, wall thickness can also increase Fibrous ring surrounding mitral valve stretches Mitral valve flaps now too far apart to meet during systole causing mitral regurgitation

Answer 45

Leaky mitral valve allows backflow of blood from ventricle to atrium

Answer 46

Endocarditis Rheumatic fever Damaged tissue

Answer 47

When the mitral valve doesn't fully close, blood leaks back from the ventricle into the atrium Blood can then backflow from the atrium into the pulmonary veins leading to the lungs Blood in the lungs increases pulmonary pressure causing the blood to be pushed into interstitial tissue Lungs become wet and damp and the surface area of alveoli decreases Less gas exchange takes place so rate of breathing goes up to maintain oxygen levels