Question

Why do you have a dedicated circulation pathway for the spleen, stomach, pancreas, gallbladder, and intestines that passes through the liver? What is it about those organs that makes the liver’s function critical to your health?

High levels of cholesterol can “clog” arteries, effectively shrinking them. What would you expect the impact of this to be on a person’s blood pressure levels and overall health (ignoring any issues with plaque breaking off and causing other issues)?
Why does your left ventricle need a much thicker muscle layer than the right ventricle?
Heart disease is one of the most common causes of death in the United States, especially for people 65 and over; even people who survive heart disease might have to limit certain kinds of activities (exercising too much, drinking alcohol, and so on). Blood vessels also lose elasticity as we age. Why would you guess that older people are more susceptible to heart diseases, compared to younger people?
How are systemic and pulmonary circulation interdependent? How do they rely on each other?

Answer 1

1. 1. The liver plays a critical role in metabolizing nutrients from those organs and filtering toxins from the blood. The portal vein carries blood from those digestive organs to the liver so it can perform those functions before the blood circulates to the rest of the body.

2. High cholesterol levels and clogged arteries would increase a person's blood pressure. The heart has to pump harder to force blood through the narrowed arteries, which raises the pressure. It also reduces blood flow to organs and tissues, impairing their function over time. This can lead to health issues like hypertension, heart disease, and organ damage.

3. The left ventricle pumps blood out to the entire body, so it needs to generate much higher pressures than the right ventricle, which only pumps to the lungs. The thicker muscle layer gives the left ventricle more power to pump against the higher resistance of the systemic circulation.

4. Older people are more prone to heart disease for several reasons:

• • Their arteries and blood vessels lose elasticity over time, which raises blood pressure and makes the heart work harder.
• • Plaque has had more time to build up in their arteries, narrowing and hardening them.
• • The heart muscle weakens slightly with age, so it's less able to pump forcefully.
• • Other health issues like high blood pressure, diabetes, and high cholesterol are more common in older adults and put extra strain on the heart.
• • Lifestyle factors like lack of exercise, poor diet, smoking, and excess weight gain over many years also contribute to heart disease risk.

5. The systemic and pulmonary circulations rely on each other to provide oxygenated blood to the body and deoxygenated blood to the lungs. Oxygen-depleted blood from the systemic circulation is pumped to the lungs by the right side of the heart. The lungs oxygenate the blood and pump it back to the left side of the heart, which then circulates it out to the body again. So the two circulations work together in a closed loop to sustain blood flow and oxygen supply throughout the entire cardiovascular system.