MDC 3 Final Exam 1. Responsibility of the Heart - -transports O2 and CO2 -transports nutrients & wastes -transports hormones -protects against disease & infections -regulates body temp 2. Cardiovascular disease is the - leading cause of death in the US 3. Anatomy of the heart - fist size organ and pumps approx: *60ml with each beat and 5L every minute* (can be increased when demand increases) 4. Blood flow steps of the heart - 1. Right atrium receives deoxygenated blood from superior inferior vena cava 2. right ventricle received blood via the trcupsid valve 3. right ventricle contracts and pumps blood through the pulmonic valve into the pulmonary artery for gas exchange 4. left atrium receives oxygenated blood from the pulmonary veins 5. left ventricle receives blood via the mitral valve 6. the left ventricle contracts and pumps blood to the body via the aortic valve 5. Age related changes - -cardiac valves -conduction system -left ventricle -aortic & other large arteries -Baroreceptors 6. How do the cardiac valves change with increased age? - -murmurs appear -valvular abnormalities result in rhythm changes 7. How does the conduction system change with increased age? - -Pacemaker cell decreases (the regulator of the heart) -Fibrous tissue & SA node increase (the heart gets thicker) -Decrease muscle fibers in atrial myocardium and bundle of His -Conduction time increases (bradycardia possible) 8. How does the left ventricle change with age? - -size increases (cardiomyopathy) -walls stiffen (stroke volume and ejection fraction decrease) -Fibrotic changes happen (filling speed is decreased and less able to increase cardiac output activity) 9. How does the aorta and large arteries change with age? - walls thicken and stiffen (*main responsibility of hypertension in older adults*) 10. How do the baroreceptors work? - They have a set point that the blood pressure should be at and make changes to the heart rate to change the blood pressure. 11. How do the baroreceptors change in age? - they become less sensitive bc they are responsible for knowing when to increase or decrease the flow of blood based on the increase or decrease of movement they are responsible for *orthostatic changes which lead to increased dizziness and fainting* 12. Remember that systole is _____ and distole is _______ - -systole is CARDIAC CONTRACTION -distole is CARDIAC FILLING 13. Cycle of the heart - -passive filling of ventricles & atria (diastole) -Atrial contraction (atrial systole) *P wave* -Ventricular ejection (ventricular systole) 14. *Cardiac output =* - *heart rate x stroke volume* 15. *Normal CO range* (cardiac output) - *4-7 L/min* 16. Stroke volume is - the amount of blood ejected during each contraction impacted by preload, afterload, contractility, and HR 17. Stroke volume (preload) - how much the myocardial ventricle STRETCHES (impacted by volume returning) 18. Stroke volume (afterload) - how much RESISTANCE the ventricle must overcome to pump directly related to arterial blood pressure & diameter of blood vessels 19. Stroke volume (contractility) - how well the heart can constrict or relax to ensure appropriate FORCE of contraction 20. Blood pressure is - the force of blood exerted against the vessel wall