Tag Archives: circulatory system

Heart attack


Myocardial infarction, commonly referred to as heart attack, is the sudden death of part of the heart muscle (the myocardium) due to loss of blood flow (ischemia). This occurs when one of  the coronary arteries – the arteries that supply blood to the heart – is blocked.
Coronary arteries, labeled diagram.
Fig. 1: Coronary arteries supply blood to the heart. They branch out from the first part of the aorta. Click on image to see a larger version on Alila Medical Media website where the image is also available for licensing.

 

 

 

The blockage is commonly due to atherosclerosis – cholesterol plaques/fat deposits on the wall of blood vessels. As the plaque builds up, the vessel becomes narrow restricting blood flow. Under stress, the plaque may rupture. This triggers formation of blood clot on top of the plaque leading to complete blockage of blood flow.  When this happens in a coronary artery, the downstream patch of the myocardium dies from lack of oxygen (Fig. 2). Weaken heart muscle may disrupt electrical activity of the heart and cause fibrillation with subsequent cardiac arrest.
heart attack
Fig. 2: Anatomy of a heart attack due to atherosclerotic plaque. Click on image to see a larger version on Alila Medical Media website where the image is also available for licensing.

 

 

 

 

Click here to see an animation of heart attack  on Alila Medical Media website where the video is also available for licensing.

Signs and symptoms

The most common symptom is described as a heavy pressure and squeezing pain inside the chest which often radiates to the shoulder and left arm. Other symptoms include shortness of breath, sweating, weakness, nausea and vomiting.

In a number of cases, especially in elderly and people with diabetes, no chest pain or other symptoms are reported. These are called silent myocardial infarction. In such a case, myocardial infarction is diagnosed later with electrocardiograms (ECG), blood enzyme tests or an autopsy.

Risk factors and Causes

Heart attack is caused by build-up of atherosclerotic plaques. Risk factors include smoking, alcohol consumption, obesity, sedentary lifestyle, stress. Incidence increases with age, also, men are more at risk than women.

Onset of acute myocardial infarction is commonly associated with physical and/or psychological exertion. When the body is under physical or emotional stress, blood flow is increased. This leads to stretching of the wall of blood vessels and potentially rupture of plaques.

Below is a narrated animation about myocardial infarction, cardiac catheterization and coronary angioplasty. Click here to license this video and/or other cardiovascular related videos on Alila Medical Media website.


Treatments

Immediate treatments for suspected heart attack include blood thinners such as aspirin. Blood thinners are drugs that prevent further blood clotting. If this doesn’t help, another class of drugs called thrombolytic may be used. Thrombolytic drugs act to dissolve blood clots. This process is called thrombolysis.

Severe cases will require interventional therapy such as angioplasty where the blocked blood vessel is forced to open wider with a balloon and possibly a stent.

People with multiple sites of blockage may require heart bypass surgery. In this surgical procedure, a piece of healthy artery or vein taken from elsewhere in the body is used as a graft to “bypass” the blocked part of coronary artery.

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Heart, Blood and Circulation Gallery

Download illustrations of human circulatory system: gross anatomy, cardiac cycle, heart diseases and congenital defects, cardiovascular conditions and surgery treatment, blood cell formation, vascular disorders, and more.

Please note: Free downloads are intended to facilitate healthcare education for people in need in low income countries and can be used for educational purposes only. If you can afford it or if you plan to use the images for commercial purposes, please consider buying instead. You can find a larger image collection at higher resolutions for sale at affordable prices on Alila Medical Media website.

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Blood flow in vessel, medical drawing.
Blood flow in vessel, medical drawing.
Red blood cells streaming in artery
Elements of blood, medical drawing.
Elements of blood, medical drawing.
Illustration of red and white blood cells, lymphocytes, monocytes, platelets, basophil, eosinophil, neutrophil.
Atherosclerosis, unlabeled.
Atherosclerosis, unlabeled.
Blood clot forms on cholesterol plaque in artery blocking blood flow.
Atherosclerosis, labeled.
Atherosclerosis, labeled.
Blood clot forms on cholesterol plaque, blocked artery.
Process of cholesterol plaque in artery, unlabeled
Process of cholesterol plaque in artery, unlabeled
Diagram showing process of cholesterol plaque in artery, unlabeled version.
Stages of Atherosclerosis
Stages of Atherosclerosis
Process of cholesterol plaque build-up in artery, labeled diagram.
Leukemia versus normal blood count, illustration.
Leukemia versus normal blood count, illustration.
Cancer of blood, Anemia, medical drawing.
Brain stroke diagrams
Brain stroke diagrams
Ischemic versus Hemorrhagic brain stroke, unlabeled.
Blood supply to the brain diagram
Blood supply to the brain diagram
Lateral view of the brain with middle cerebral artery, unlabeled.
Stages of atherosclerosis diagram
Stages of atherosclerosis diagram
Cholesterol plaque build-up in blood vessel and formation of blood clot cause blockage of blood flow, labeled.
Clipart of healthcare icon (cardiology)
Clipart of healthcare icon (cardiology)
Magnifying glass on an ECG graph diagram
Cardiac arrhythmias ECG/ EKG set diagram.
Cardiac arrhythmias ECG/ EKG set diagram.
Normal and pathological electrocardiograms in heart diseases.
EKG and myocardium function diagram
EKG and myocardium function diagram
Phases of electrical activity of human heart, ECG cycle.
Myocardial infarction diagram (heart attack)
Myocardial infarction diagram (heart attack)
Coronary artery blocked by cholesterol plaque causing heart stroke.
Human heart blood flow
Human heart blood flow
Illustration of blood flow through the heart, labeled
Human heart blood flow
Human heart blood flow
Illustration of blood flow through the heart, unlabeled
Blood supply to the heart unlabeled diagram
Blood supply to the heart unlabeled diagram
Coronary arteries illustration, anterior view of the heart
Blood supply to the heart labeled diagram
Blood supply to the heart labeled diagram
Coronary arteries illustration, anterior view of the heart
Human heart cut, medical illustration.
Human heart cut, medical illustration.
Heart anatomy diagram, unlabeled.
Left ventricular hypertrophy labeled diagram
Left ventricular hypertrophy labeled diagram
Thickening of the myocardium of left ventricle of human heart.
Electrical pathways of the heart, unlabeled
Electrical pathways of the heart, unlabeled
The cardiac conduction system of human heart, unlabeled version.
Heart valves operation, unlabeled diagram.
Heart valves operation, unlabeled diagram.
Cycles of heart valves operation pumping blood through different chambers, aorta and veins.
Electrical pathways of the heart
Electrical pathways of the heart
The cardiac conduction system of human heart, labeled version.
Abdominal aortic aneurysm diagram
Abdominal aortic aneurysm diagram
Aneurysm in aorta of the abdomen and bleeding risk.
Deep vein thrombosis diagram
Deep vein thrombosis diagram
Abnormal blood clotting in deep leg vein and formation of thrombus.
Tetralogy of Fallot diagram
Tetralogy of Fallot diagram
Congenital heart disease: Tetralogy of Fallot, labeled
Ventricular septal heart defect diagram.
Ventricular septal heart defect diagram.
Congenital heart disease: ventricular septal defect, hole in the septum between ventricles, unlabeled.
Balloon angioplasty procedure diagram
Balloon angioplasty procedure diagram
Heart cath procedure with balloon to widen artery with plaque
Heart and lungs diagram unlabeled
Heart and lungs diagram unlabeled
Human lungs and heart anatomy, unlabeled.
Thorax anatomy unlabeled diagram.
Thorax anatomy unlabeled diagram.
Human heart cross section and lungs anatomy.
Biofeedback regulation of heart rate, medical illustration.
Biofeedback regulation of heart rate, medical illustration.
Regulation of blood pressure through baroreflex, unlabeled version.
Biofeedback regulation of heart rate, labeled.
Biofeedback regulation of heart rate, labeled.
Regulation of blood pressure through baroreflex, labeled version.
Blood supply to the head and neck, labeled drawing.
Blood supply to the head and neck, labeled drawing.
Diagram of human head anatomy with arteries including internal carotid supplying the brain, lateral (side) view, labeled.
Blood supply to the brain, coronal section.
Blood supply to the brain, coronal section.
Middle cerebral artery anatomy and distribution, labeled diagram.
Metastatic cancer, medical drawing.
Metastatic cancer, medical drawing.
Cancer cell squeezes through the endothelium of blood and lymph vessel, illustration unlabeled.
Human circulatory system diagram
Human circulatory system diagram
Anatomy of human circulation system, unlabeled.
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