Rachel
About

Khan Academy on a Stick

Health and medicine

Coronary artery disease

Heart disease and stroke

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 heart disease and vice versa. You will come to an understanding of the pathophysiology behind these common diseases and how they relate to one another.

  • Arteries vs. veins - what's the difference?

    Learn some important differences between arteries (high pressure/low volume) and veins (low pressure/high volume). Rishi is a pediatric infectious disease physician and works at Khan Academy.

  • Arteriosclerosis, arteriolosclerosis, and atherosclerosis

    Learn the difference between Arteriosclerosis, Arteriolosclerosis, and Atherosclerosis! Rishi is a pediatric infectious disease physician and works at Khan Academy.

  • Atherosclerosis - part 1

    See how Atherosclerosis (Fat in the blood vessel wall) hardens the arterial wall and makes it harder for blood to flow through. Rishi is a pediatric infectious disease physician and works at Khan Academy.

  • Atherosclerosis - part 2

    See how Atherosclerosis (Fat in the blood vessel wall) hardens the arterial wall and makes it harder for blood to flow through. Rishi is a pediatric infectious disease physician and works at Khan Academy.

  • Arteriolosclerosis - part 1

    See how hyaline arteriolosclerosis (Protein in the arterial wall) causes hardening of the blood vessels. Rishi is a pediatric infectious disease physician and works at Khan Academy.

  • Arteriolosclerosis - part 2

    See how hyperplastic arteriolosclerosis (Protein in the arterial wall) makes it difficult for blood to go through blood vessels. Rishi is a pediatric infectious disease physician and works at Khan Academy.

Blood vessel diseases

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.

  • What is hypertension?

    Learn the categories of hypertension for systolic and diastolic blood pressures. Rishi is a pediatric infectious disease physician and works at Khan Academy.

  • Hypertension symptoms and categories

    Learn the most common symptoms (or lack thereof!) and the two major categories of hypertension. Rishi is a pediatric infectious disease physician and works at Khan Academy.

  • Hypertension effects on the blood vessels

    Learn about how hypertension can cause damage to the large/middle sized arteries as well as the small arteries and arterioles. Rishi is a pediatric infectious disease physician and works at Khan Academy.

  • Hypertension effects on the heart

    Learn 2 major heart problems that hypertension can cause. Rishi is a pediatric infectious disease physician and works at Khan Academy.

  • 4 lifestyle changes to help manage hypertension

    Remember that a good diet, exercise, losing weight, and quitting smoking can lower blood pressure! Rishi is a pediatric infectious disease physician and works at Khan Academy.

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!

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.

  • What is acyanotic heart disease?

    Acyanotic heart disease is a group of heart conditions where blood with oxygen mixes with blood with little oxygen in the heart. This mixing is not enough to cause cyanosis, a symptom of not enough oxygen being delivered to tissues of the body, hence the name acyanotic heart disease.

  • Acyanotic heart disease diagnosis

    How do we know a patient has an acyanotic heart disease? Learn how health care professionals use a variety of tools to diagnosis these conditions, such as stethoscopes, chest x-rays, echocardiogram, and electrocardiograms (ECG or EKG).

  • What is Eisenmenger syndrome?

    Eisenmenger's syndrome is when blood in the heart shunts from right-to-left due to increased pressure in the right ventricle. This increased pressure is usually caused by extra blood flowing through the blood vessels of the lungs, originally caused by left-to-right shunting of blood from a hole in the heart wall.

  • Atrial septal defect

    An atrial septal defect is a hole between the two atriums of the heart. Normally this hole is present at birth but closes within a few days of life. Failure of this hole to close is called an atrial septal defect, and usually is asymptomatic (no obvious symptoms are present).

  • Ventricular septal defect

    An ventricular septal defect is a hole between the two ventricles of the heart. Normally this hole is present at birth but closes within a few days of life. Failure of this hole to close is called a ventricular septal defect, and usually is asymptomatic (no obvious symptoms are present).

  • Patent ductus arteriosus

    Patent ductus arteriosus is a medical condition where a blood vessel called the ductus arteriosus does not permanently close after birth. Learn why the ductus arteriosus does not close, why patients with this condition have a wide pulse pressure, and how the disease is treated with surgery and nonsteroidal anti-inflammatory drugs (NSAIDs).

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

  • What is vasculitis?

    Vasculitis is a group of medical conditions which cause damage to the blood vessels through inflammation. Depending on which blood vessels are affected, vasculitis can be classified as large vessel, medium vessel, or small vessel vasculitis. Learn about the signs and symptoms of vasculitis such as purpura, bloody stool and urine, and bruits.

  • Vasculitis pathophysiology

    Vasculitis occurs when antibodies (part of the immune system of the body) accidentally mistake the proteins on blood vessels to be foreign (don’t belong in the body). The immune system attacks the blood vessel cells and damages them. Learn how fibrinoid necrosis occurs to the blood vessels, and how the build up of fibrin impairs blood flow.

  • Temporal arteritis

    Temporal arteritis (otherwise known as giant-cell arteritis) is a type of vasculitis that affects medium to large arteries in the head. Patients with temporal arteritis can have symptoms like migraines and sudden vision problems. Learn how health care professionals diagnosis temporal arteritis by examining blood work (such as erythrocyte sedimentation rate, granulomas) and taking samples (biopsies) of vascular tissue.

  • Takayasu arteritis

    Takayasu arteritis (also known as the pulseless disease) is a type of vasculitis that affects large arteries and leads to significant narrowing of the vasculature. Patients with takayasu arteritis can have symptoms like weak or absent pulses in extremities, widely varying blood pressures, and dizziness. Learn how health care professionals diagnosis takayasu arteritis by examining blood work (such as erythrocyte sedimentation rate, granulomas), and taking samples (biopsies) of vascular tissue,

  • Polyarteritis nodosa

    Polyarteritis nodosa is a type of vasculitis that affects small to medium arteries and leads to significant narrowing of the vasculature. Patients with polyarteritis nodosa can have symptoms like bloody diarrhea, skin lesions, and impaired motor function caused by neuropathy. Learn how health care professionals diagnose and treat polyarteritis nodosa by examining arteriograms and prescribing steroids.

  • What is Kawasaki disease?

    Kawasaki disease (also known as mucocutaneous lymph node syndrome) is a type of vasculitis that affects medium arteries. Patients with Kawasaki disease can have symptoms like rashes on the palms of hands, soles of feet, in the eyes, and on the tongue (called strawberry tongue).

  • Kawasaki disease: diagnosis and treatment

    Kawasaki disease is diagnosed off the presence of symptoms rather than the results of tests. Symptoms include: conjunctivitis, rash, adenopathy, strawberry tongue, and rash on palms and soles of hands and feet. Four of these symptoms must be present, in addition to a fever which has lasted more than 5 days to confirm a diagnosis. Learn about atypical Kawasaki disease, and how health professional treat the disease using intravenous immunoglobulins (IVIG) and acetylsalicylic acid.

  • Buerger disease

    Buerger disease (also known as the thromboangiitis obliterans) is a type of vasculitis that affects small and medium blood vessels and has been linked strongly to smoking. Buerger disease is characterised by poor blood flow through blood vessels due to inflammation and blood clotting. Symptoms typically include pain (claudication), increased sensitivity to cold, diminished pulses, and cyanosis. Gangrene is often a complication which may require amputation of the affected area. Learn how health care professionals diagnose Buerger disease using ultrasound and angiography.

  • Wegener’s granulomatosis and microscopic polyangiitis

    Wegener’s granulomatosis (also known as granulomatosis with polyangiitis) is a type of vasculitis that affects small and medium blood vessels. Symptoms can include saddle nose deformity, chronic sinusitis, and collapsed trachea. Microscopic polyangiitis is similar to wegener’s granulomatosis except it only affects small blood vessels in the lungs or kidneys. Learn how the presence of granulomas and antibodies (cANCA and pANCA) differentiate these two conditions.

  • Churg-Strauss syndrome

    Churg-Strauss syndrome (also known as eosinophilic granulomatosis with polyangiitis) is a type of vasculitis that affects small and medium blood vessels. Symptoms of this disease are similar to seasonal allergies, such as runny nose, cough, sneezing. Health professionals diagnosis Churg-Strauss syndrome by examining eosinophil levels and pANCA antibody levels, in addition to the presence of granulomas from a tissue sample (biopsy).

  • Henoch-Schonlein purpura

    Henoch-Schonlein purpura (also known as anaphylactoid purpura) is a type of vasculitis that affects small blood vessels and characterized by elevated immunoglobulin A (IgA). Symptoms of this disease include skin lesions, joint pain, blood in urine (hematuria), and abdominal pain. Health professionals diagnosis Henoch-Schonlein purpura through blood tests (elevated IgA). This disease is often treated with steroids.

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.

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.

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.

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.Hell

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.

Heart valve diseases