Circulatory system diseases

This course is a part of Health and medicine, a 22-course Topic series from Khan Academy.

With the heart pumping 24/7, it’s crucial that things flow smoothly (pun intended!). Unfortunately, this isn’t always the case. The underlying reasons for circulatory system problems vary from your genes to your lifestyle. To combat this growing problem in the world, we need a better understanding of these diseases.

This course contains 15 segments:

Coronary artery disease

Coronary artery disease - clogging of the arteries supplying the heart- is the cause of about 30% of all deaths globally, making it the leading cause of death. Stroke is a similarly debilitating condition that results from lack of perfusion to the brain. Unfortunately, patients with heart disease are more likely to suffer from respiratory system disease and vice versa. You will come to an understanding of the pathophysiology behind these common diseases and how they relate to one another.

Atherosclerosis, arteriosclerosis, and arteriolosclerosis

The ancient Greeks thought blood vessels actually carried air throughout the body. Although we know better today, many people are still often confused with the specifics! We now know that the vessels carry blood instead, and we are able to distinguish between two different types: arteries and veins. Learn about how arteries differ from veins and how vessels can get damaged over time.

Stroke

Hypertension

Nearly one billion people in the world have high blood pressure. That’s 1 in every 7 people! With the amount of unhealthy foods becoming increasingly available to everyone, it makes sense that this number is climbing. This set of videos will explore high blood pressure, also known as hypertension. Learn more about it, what it does to different parts of the body, symptoms of hypertension, and what you can do with your everyday life to manage it!

Heart failure

Aortic dissection and aneurysm

When a patient with hypertension and chest pain radiating to the back presents to the hospital, one should suspect aortic dissection, which is a tear of the inner lining (tunica intima) of the aorta, with dissection of blood through its middle layer (tunica media). And when an elderly male presents with a pulsatile abdominal mass, one should suspect a rupturing abdominal aortic aneurysm. An aneurysm is simply a balloon-like dilation of a vessel wall. You will come to an understanding of the pathophysiology of these life-threatening diseases in addition to their surgical and medical management.

Myocarditis and pericarditis

Inflammation of the heart muscle and the fibrous sac surrounding the heart are called myocarditis and pericarditis, respectively. Each of these disorders present with specific signs and symptoms. For instance, pericarditis sometimes presents with a subtle finding when listening to the heart with the stethoscope, termed the friction rub. You will come to appreciate the clinical differences between these diseases as well as their therapeutic management.

Cardiomyopathy

Cardiomyopathy encompasses a group of diseases in which the myocardium (heart muscle) is unable to contract, leading to cardiac dysfunction. These flavors come in three flavors - dilated, restrictive, and hypertrophic. Patients unfortunately are at risk for heart failure, arrhythmias, and sudden cardiac death. We will discuss the signs and symptoms of the cardiomyopathies as well as what clinicians can do to treat these conditions.

Cardiac dysrhythmias and tachycardias

Your heart is an electrical organ, and it produces a rather rhythmic music - lub-dub, lub-dub. We are able to measure its music through the electrocardiogram (EKG), which is able to pick up pathological rhythms - supraventricular tachycardias, atrial fibrillation, and ventricular tachyardia for instance- through electrical leads placed on the chest. We will discover how to identify these dysrthymias as well as how these conditions are treated, such as through the use of anti-arrhythmic drugs and pacemakers.

Heart valve diseases

Acyanotic heart diseases

Acyanotic means, quite simply “not blue.” When deoxygenated blood is pumped out by our heart into our vessels. Fortunately, not all congenital heart diseases result in cyanosis. In this module, we will discuss these acyanotic heart diseases, from atrial septal defect to patent ductus arteriosus as well as the embryological defects that lead to them.

Cyanotic heart diseases

Shock

Shock is a rather common clinical situation, especially in the emergency room. Quite simply, circulatory shock refers to poor perfusion of organs with blood. For example, shock may result from loss of blood (hemorrhage), a poorly functioning heart (heart failure), or dilated blood vessels (sepsis and anaphylactic shock). We will explore how to differentiate the many different causes of shock here.

Vasculitis

Inflammation of the blood vessel wall is termed “vasculitis,” though the etiology of these diseases are rather nebulous. They present with nonspecific symptoms like fever, fatigue, weight loss. Large, medium, and small vessels can all be involved. We will explore the specific differences between the various vasculitides, which range from Takayasu arteritis to microscopic polyangitis.

Hypertension