Cardiovascular system Flashcards
What is the intro to viva script including: what it is made up of and location.
- Made up of blood, blood vessels and the heart
- Muscular organ works as a pump- diastole and systole
- Located behind the sternum, apex 4th intercostal, base 3rd
What are the main functions of the CVS
- Provide the body with nutrients, glucose
- Remove the waste products e.g. CO2 lactic acid
- Provide organs with oxygenated blood
What 3 structures make up the cardiac layers and describe them
Endocardium, Myocardium and Pericardium
What is the Endocardium layer?
- Endocardium is the innermost layer that lines the inner surfaces of the heart for example heart valves and is made up of loose tissues and epithelial tissues.
What is the myocardium layer?
- The Myocardium is the middle thickest layer which controls the contraction of the heart as it is made up of single nucleus cells of cardiomyocytes.
What is the pericardium layer?
- The Pericardium is the outermost layer which is made up of two sacs. One being for lubrication one being to prevent over distention tough and inelastic
Describe the journey of blood from the heart beginning at blood returning from the body
- Deoxygenated blood in through the inferior vena cava
- To RA where it passivley fills
- From RA to RV via tricuspid valve (prevents backflow)
- Systole occurs forcing the RV to push the blood to the pulmonary trunk through pulmonary valve
- Blood goes through the pulmonary arteries to the lungs to become oxygenated
- returns to heart via pulmonary veins
- Enter the LA
- Passes through the bicuspid valve into LV
- ventricular systole causes blood to be pushed through the aortic valve into the aorta
- Aorta carries blood to the body and target organs
How does deoxygenated enter the heart?
Through the inferior and superior vena cavas
How does the blood exit the heart to become oxygenated
Through the left and right pulmonary arteries
State the difference between pulmonary arteries and pulmonary veins
Pulmonary veins return oxygenated blood from the lungs to the heart and Left atrium.
Pulmonary arteries take deoxygenated blood from the heart to the lungs where gaseous exchange happens.
What are the 3 stages in the cardiac cycle
Atrial systole
Ventricular systole
Ejection/diastole
Describe the first stage of the cardiac cycle
Atrial systole
- ECG: P wave, atrial depolarisation (contraction)
- Atrial pressure increases
- Ventricular volume increases
-
Describe the second stage of the cardiac cycle
ventricular systole
ECG: QRS complex, ventricular depolarisation (contraction)
- Ventricular volume: stays the same
- Ventricular pressure: increases signifcantly, needs to get above aortic pressure to open semi-lunar valve and travel to the aorta
- when the pressure gets above the aortic pressure, blood is ejected out the semi-lunar valve and the blood exits through the aorta
Describe the 3rd stage of the cardiac cycle
Ejection stage:
- ECG: T wave
- Ventricular volume: decreases, blood is ejected
- ventricular pressure: decreases, once it gets below the aortic pressure the semi-lunar valve shuts again
- Aortic pressure: remains high
- Blood: travels back to the atria to passivley fill until the next P wave.
Describe and explain the phonocardiogram during the cardiac cycle
Lub sound- ventricular depolarisation, contraction, bicuspid valves shutting, QRS
Dub sound- When t wave, the shutting of the semi-lunar valve
What is cardiac output
the volume of blood ejected per minute
Made up of two factors: stroke volume and heart rate
What can influence stroke volume+ what is it
Stroke volume= amount of blood ejected per contraction
-Preload: elasticity of the heart and the stretch the heart walls undergo based on the volume of blood that fills at the end diastolic stage. Frank Starlings Law states that the amount of stretch/ the more the heart valves have to stretch, the greater the contractability reflex of the heart is= the greater ejection and more volume is ejected.
- Afterload, this refers to the resistance of that the blood faces during the ejection stage e.g. thinner arteries= more resistance, wider arteries= less resistance
- Heart contractibility- calcium is needed for the cardiomyocytes to contract, impact of calcium iontropics can increase or decrease calcium production. E.g. noradrenaline stimulates calcium production, helps the heart contract- cardiac arrest application
