Heart Health

Atherosclerotic disease is a global health problem. Cardiovascular disease is the number 1 cause of death worldwide, claiming 12 billion lives annually in developing countries. In the US heart disease claims about 800,000 deaths per year. It is estimated 80% of deaths from cardiovascular disease worldwide occur in low-income and middle income countries. The high mortality is partly due to lack of access to care in many areas, but the problem will not be solved by better medical care.

Atherosclerotic is a complex process by which arteries become progressively narrowed, impairing the supply of oxygen. Impaired blood flow can result in ischemia and cause angina or intermittent claudication. Plaques can also rupture, triggering acute formation of a clot and abrupt loss of blood supply to tissues, resulting in an infarction.

Eventually, progression of atherosclerosis  generally can manifest itself in three ways:

• Coronary artery disease
  
• Cerebrovascular disease
• Peripheral artery disease

Learning Outcomes

1. Define atherosclerosis and describe the basic mechanism by which it develops, including response to injury theory
2. Compare and contrast the terms ischemia and infarction
3. Explain the mechanisms by which poorly controlled diabetes and hypertension contribute to heart disease
4. Discuss the risk factors for atherosclerotic cardiovascular disease

The Cardiovascular System

The primary function of the heart and blood vessels is to transport oxygen, nutrients, and byproducts of metabolism. Oxygen and nutrient-rich blood is delivered to tissues via the arterial system which branches into smaller and smaller blood vessels; from arteries to arterioles to capillaries (where most exchange occurs).

The heart is a discrete organ which has 4 chambers (in humans). Two chambers on the right side (right atrium and right ventricle) receive blood returning from the periphery and send it too the lungs for re-oxygenation. Blood then returns on the left side via pulmonary veins. After entering the left atrium blood enters the left ventricle and is pumped back into the aortic arch for distribution to the body.

Note also that the heart requires a continuous supply of oxygen an nutrients, just like any other tissue. The heart receives its blood supply from coronary arteries which arise from the root of the aorta.

All blood vessels (arteries and veins) have 3 primary layers: Intima, media, and adventitia. Normally, the walls of an artery are smooth to allow unobstructed blood flow. The innermost layer. intima, is lined with indothelial cells which are in direct contact with blood.

Atherosclerosis