Heart Anatomy and Blood Flow for EKG Technicians
Updated October 27, 2026
To understand an EKG, it helps to know the heart’s structure and how blood moves through it. Here’s the anatomy EKG technicians need, followed by free practice questions.
Chambers
| Chamber | Job |
|---|---|
| Right atrium | Receives oxygen-poor blood from the body |
| Right ventricle | Pumps blood to the lungs |
| Left atrium | Receives oxygen-rich blood from the lungs |
| Left ventricle | Pumps blood to the whole body; has the thickest wall |
The path of blood
- Body → superior and inferior vena cava → right atrium
- → tricuspid valve → right ventricle
- → pulmonary valve → pulmonary arteries → lungs (blood picks up oxygen)
- Lungs → pulmonary veins → left atrium
- → mitral (bicuspid) valve → left ventricle
- → aortic valve → aorta → body
Coronary arteries
The heart muscle gets its own blood supply from the coronary arteries, which branch off the aorta. The main ones are the left coronary artery (which divides into the left anterior descending and circumflex arteries) and the right coronary artery. A blockage in a coronary artery can cause a heart attack, which may show up as changes on the EKG.
Free practice questions
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Which chamber pumps oxygen-rich blood to the body?Answer: DThe left ventricle pumps oxygenated blood into the aorta and out to the body, which is why it has the thickest wall.
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Which valve lies between the right atrium and right ventricle?Answer: AThe tricuspid valve separates the right atrium from the right ventricle. The mitral valve is on the left side.
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Where does blood go after leaving the right ventricle?Answer: CThe right ventricle pumps oxygen-poor blood through the pulmonary valve into the pulmonary arteries to the lungs.
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Which vessels bring oxygen-rich blood from the lungs back to the heart?Answer: BThe pulmonary veins carry oxygen-rich blood from the lungs to the left atrium.
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What supplies the heart muscle itself with blood?Answer: CThe coronary arteries branch off the aorta and supply oxygen-rich blood to the heart muscle.
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Which valve does blood pass through as it leaves the left ventricle?Answer: DBlood leaves the left ventricle through the aortic valve into the aorta and out to the body.
Pass your EKG technician exam on the first try
- All 190 questions on safety and compliance, patient care, EKG acquisition and rhythm analysis
- An explanation for every answer, with the AHA recommendation, OSHA rule or guideline behind it
- Unlimited full 100-question practice exams, with each domain in its real share