Wk.3 L3 - Cardiovascular Changes though the lifespan Flashcards
LO
- Describe age-related physiological changes in the heart and cardiovascular system
- Outline common cardiovascular conditions associated with aging
Blood vessel maturation
Allows increased regulation of blood pressure through:
- Smooth muscle cell recruitment
- Deposition of elastin
Foetal circulation
Foetal:
1. Oxygenated blood comes from the placenta
2. From Placenta throughtoetal shunt into inferior vena cava
3. From R. artium the blood goes to R. Ventricle
4. From R. ventricle it bypasses the liver due to high psi in lungs and goes straight into left atrium through the foramen ovule to L. atrium
5. From L. atrium to L. Ventricle and out to body
- If any blood makes it into the pulmonary circulation, it will travel through another feotal shunt back to the aorta
Post-Natal circulation
- Once the umbilical cord is cut, the pressure in the lungs drops to allow breathing and blood to the pulmonary circulation
- Noraml blood flow is established
- As the L. Ventricle pumps, the foramen ovule closes due to the one way valve structure
- As pressure is kept on the foramen ovule, it fuses to form a wall.
- The foetal shunt regresses aand becomes other components
Heart anatomy changes
- Foramen ovule closes seperating the 4 chambers fully
- Thickening of the L. ventricle wall to increase heart pumping strength
Cardiac performance
CO = HR x SV
SV = volume of blood per beat projected
CO = volume of blood pumped per given time (per ventricle)
Factors of HR
- Autonomic innervation
- Hormones
- Fitness levels
- Age
Factors of SV
- Heart size
- Fitness levels
- Gender
- Contractility
- Duration of contraction
- Preload (EDV)
- Afterload (resistence)
Declining Cardiac performance over time
HR higher when younger, compensate for smaller hearts
- With age HR declines due to sinoatrial node dyfsunction and Autonomic NS de-sensitivity
mHR = 220-age
Myocardial and Vascular stiffening
- Less elastic over time
- Occurs through fibrosis - Firbroblasts produce more collagen
- A reduced breakdown of collagen imparis elasticity
Fibrosis in Heart = decreased pumping efficiency
Fibrosis of vasculature = increased pressure and hypertension
Endothelial dysfunction
- With hypertension, some endothelial cells may die
- Atheroscleosis can occure with plaque build ups and increased hypertension
