3.3 Flashcards
(10 cards)
- What are the key age-related changes that occur in the heart as we age?
With aging, the heart exhibits a decline in maximum and resting heart rate (due to a loss of pacemaker cells and autonomic de-sensitivity), reduced stroke volume from diminished contractility and increased myocardial stiffness, and increased cardiac fibrosis—all contributing to a gradual reduction in overall cardiac output.
- How does aging affect the structure and function of large arteries such as the aorta?
Aging leads to structural changes in large arteries, including increased collagen deposition and loss of elastin, which result in stiffer vessels with decreased elastic recoil. This reduced compliance elevates systolic blood pressure and widens pulse pressure, impacting overall blood flow regulation.
- What is endothelial dysfunction and how is it linked to the aging vascular system?
Endothelial dysfunction refers to the reduced ability of blood vessel linings to properly regulate vascular tone, largely due to decreased nitric oxide production and increased oxidative stress. With aging, these changes contribute to impaired vasodilation, promoting hypertension and atherosclerosis.
- How is cardiac output affected by the aging process?
Cardiac output declines with age primarily because of a reduced maximum heart rate (expressed by the approximate formula 220 – age) and a decrease in stroke volume due to myocardial stiffening and fibrosis, which together lower the amount of blood pumped per minute.
- What role does cardiac fibrosis play in the aging heart?
Cardiac fibrosis, characterized by excessive collagen deposition with reduced clearance, stiffens the myocardium. This disrupts efficient electrical conduction and contraction, thereby reducing the heart’s pumping efficiency and increasing the risk for heart failure.
- How do age-related changes in the vascular system contribute to hypertension?
As arteries stiffen with age, their loss of elasticity causes the systolic blood pressure to rise, while diastolic pressure may fall, resulting in a widened pulse pressure. Together with endothelial dysfunction and increased peripheral resistance, these changes contribute to the development of hypertension.
- What are common cardiovascular conditions associated with aging?
Aging is linked to several cardiovascular conditions, including hypertension, coronary artery disease from progressive atherosclerosis, heart failure, arrhythmias (due to conduction system degeneration), and valvular heart disease such as aortic stenosis.
- How does the decline in maximum heart rate with age affect exercise capacity?
The decline in maximum heart rate reduces the heart’s capacity to increase cardiac output during physical exertion, which limits exercise capacity and contributes to a general decrease in overall cardiovascular performance in older adults.
- What microvascular changes occur in the cardiovascular system with aging?
At the microvascular level, aging results in a reduction in capillary density and impaired function of the endothelial cells lining the capillaries, thereby reducing efficient nutrient and oxygen exchange in the tissues.
- How can lifestyle factors mitigate age-related cardiovascular changes?
Regular physical exercise, a balanced diet, avoiding smoking, managing stress, and maintaining a healthy weight can all help preserve vascular elasticity, reduce oxidative stress, maintain endothelial function, and thus lessen the severity of age-related cardiovascular changes.
