Heart Disease - Atherosclerosis

What do you know about heart disease? What words come to mind? What kind of images? Any other associations?

How would you define heart disease? Heart disease describes a number of diseases that reduce functionality and/or efficiency of the heart.

Heart disease - Atherosclerosis Goals Define and describe atherosclerosis. Understand atherogenesis / plaque formation. List symptoms of atherosclerosis.

Image: BodyParts3D, © The Database Center for Life Science. Our blood vessels are responsible for moving important molecules to our cells all over our bodies. Our cells need oxygen, glucose, nutrients, and much more. They get them from our blood. Image: BodyParts3D, © The Database Center for Life Science.

Atherosclerosis (ath. er. oh. skler. oh Atherosclerosis (ath.er.oh.skler.oh.sis) is a disease of the arteries. It can occur anywhere in the body. We will learn about coronary (heart) atherosclerosis.

Atherosclerosis begins with microscopic damage to the smooth, thin layer of the interior walls of arteries. This damage can be caused by many things – poor diet, tobacco use, high blood pressure, diabetes, and many other factors. Damage Healthy artery cross section Damaged artery cross section Image: Blausen.com staff. "Blausen gallery 2014". Wikiversity Journal of Medicine.

The microscopic damage creates an opening that allows solid materials from the blood to enter and get stuck between the layers of the artery wall. cross-section of artery wall opening interior artery wall connective tissue smooth muscle cells more smooth muscle cells and layers of the artery

Low density lipoproteins (LDLs) – protein molecules attached to fat & cholesterol – enter and pick up a “free radical” oxygen molecule. This triggers the body’s inflammatory (swelling) and immune response. Macrophages (white blood cells) are sent out to engulf/destroy the invaders. white blood cell engulfing an LDL LDL interior artery wall connective tissue smooth muscle cells more smooth muscle cells and layers of the artery

The macrophages become trapped inside the wall of the artery causing the artery wall to swell at the damage site. This is the beginning of atherosclerosis, known as atherogenesis. interior artery wall connective tissue smooth muscle cells more smooth muscle cells and layers of the artery

The macrophages become fatty masses called foam cells The macrophages become fatty masses called foam cells. More material is trapped in this space over time. As more material is trapped, the opening of the artery that allows blood through (the lumen) narrows. lumen cross-section of artery narrowing of artery foam cells

The smooth muscles near the damage produce collagen (a fibrous protein) that forms a dense layer around the foam cells. At this point, the whole mass is a called a plaque, often referred to as “hardened arteries”. plaque

Atherosclerosis may not produce any symptoms until the plaque is large enough to severely limit blood flow through a coronary artery. A person may experience shortness of breath, fatigue, and/or chest pain/pressure called angina when the plaque gets large enough.

If left untreated, coronary atherosclerosis can lead to ischemia – a reduction of function and efficiency of the heart and chronic angina. Or worse, it could lead to a complete blockage of an artery either through slow growth or by rupturing and causing a blood clot.

A complete blockage will damage the heart muscles A complete blockage will damage the heart muscles. When this leads to irregular heart function accompanied by chest, left arm, and/or neck pain or tingling, fatigue and shortness of breath, it is called myocardial infarction (heart attack). It can also lead to cardiac arrest – stopping the heart altogether.

What can we do about it? Personal What choices do you have? How can you prevent heart disease? Community What can we do to prevent and treat heart disease? How can our neighborhoods change in ways that might reduce heart disease? Get a discussion started with your students. Keep asking questions to push them further and to check for understanding. You may want to record their answers on the board, computer, posterboard, etc. Possible answers: Personal Choices – what to eat, physical activities, personal responsibility, etc. Prevent - eat a healthy diet, exercise, medicine, high fiber foods, educate others, etc. Community Prevent/Treat – teach about it in schools, “vote with our dollars”, write letters to government/corporations, etc. Change – more people buying healthier foods leads to stores carrying healthy foods and maybe new stores with healthy foods, healthier families make for happier families, more people exercising outside, etc.