Overview
The cardiovascular system circulates blood throughout the body to deliver oxygen and nutrients, remove carbon dioxide and other waste products, and maintain blood pressure and tissue perfusion.
It consists of the heart, blood vessels, and blood.
The right side of the heart pumps blood to the lungs, while the left side pumps oxygen-rich blood throughout the body.
Major Structures
Heart
The heart is a muscular organ containing four chambers and four valves that maintain one-way blood flow.
- Right Atrium: Receives oxygen-poor blood returning from the body.
- Right Ventricle: Pumps oxygen-poor blood to the lungs through the pulmonary arteries.
- Left Atrium: Receives oxygen-rich blood returning from the lungs.
- Left Ventricle: Pumps oxygen-rich blood to the body through the aorta.
- Heart Valves: Prevent backward blood flow.
- Tricuspid Valve: Right atrium → right ventricle.
- Pulmonary Valve: Right ventricle → pulmonary artery.
- Mitral (Bicuspid) Valve: Left atrium → left ventricle.
- Aortic Valve: Left ventricle → aorta.
- Coronary Arteries: Supply oxygen-rich blood to the heart muscle itself.
Blood Vessels
- Arteries: Carry blood away from the heart, generally under higher pressure.
- Arterioles: Small arteries that regulate blood flow into capillary networks and contribute to vascular resistance.
- Capillaries: Microscopic vessels connecting arterioles and venules, allowing exchange of gases, nutrients, and waste products.
- Venules: Small vessels that collect blood from capillaries and drain into larger veins.
- Veins: Return blood toward the heart, often containing valves that prevent backward flow, particularly in the limbs.
Important: Arteries and veins are defined by the direction of blood flow, not oxygen content. Pulmonary arteries carry oxygen-poor blood, while pulmonary veins carry oxygen-rich blood.
Blood
Blood is a specialized connective tissue consisting of plasma and formed elements.
- Red Blood Cells (Erythrocytes): Transport oxygen using hemoglobin and carry some carbon dioxide.
- White Blood Cells (Leukocytes): Support immune defense and fight infection.
- Platelets (Thrombocytes): Help form blood clots to stop bleeding.
- Plasma: Liquid portion of blood, mostly water, containing proteins, electrolytes, nutrients, hormones, and waste products.
Key Processes
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Pulmonary Circulation: Blood travels from the right side of the heart to the lungs for gas exchange, then returns to the left side.
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Systemic Circulation: Oxygen-rich blood travels from the left side of the heart to the body, and oxygen-poor blood returns to the right side.
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Cardiac Cycle: Repeated contraction and relaxation of the heart.
- Systole: Ventricles contract and eject blood.
- Diastole: Ventricles relax and fill with blood.
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Heart Rate: Number of heartbeats per minute.
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Stroke Volume: Amount of blood pumped by one ventricle with each heartbeat.
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Cardiac Output: Volume of blood pumped by one ventricle per minute.
Cardiac Output = Heart Rate × Stroke Volume
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Blood Pressure: Force exerted by circulating blood against vessel walls, typically measured in the arteries.
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Systemic Vascular Resistance: Resistance to blood flow through the systemic circulation, influenced strongly by arteriolar diameter.
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Tissue Perfusion: Delivery of blood to tissues to supply oxygen and nutrients.
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Hemostasis: Process of stopping bleeding through vessel responses, platelet activity, and coagulation.
Effects of Aging
- Increased Arterial Stiffness: Large arteries become less elastic, contributing to higher systolic blood pressure.
- Reduced Cardiac Reserve: The heart may be less able to increase its pumping performance during exertion or illness.
- Changes in Heart Muscle: Heart walls may thicken, and ventricular relaxation and filling may become less efficient.
- Changes in Heart Valves: Valves may thicken or stiffen, increasing the likelihood of valve dysfunction.
- Reduced Blood Pressure Regulation: Less sensitive pressure receptors can contribute to dizziness or Orthostatic Hypotension when changing positions.
- Increased Susceptibility to Arrhythmias: Changes in the heart’s electrical conduction system can increase the risk of abnormal heart rhythms.
Clinical Implications
- Increased vulnerability to cardiovascular disease.
- Greater risk of dizziness and falls when changing positions.
- Reduced exercise tolerance and increased fatigue during activity.
- Greater importance of monitoring blood pressure, pulse, and changes from baseline.
- Observe swelling, shortness of breath, chest discomfort, and reduced activity tolerance.
Important: Anemia, markedly reduced white blood cell counts, uncontrolled hypertension, and heart failure are not inevitable consequences of normal aging. New abnormalities require evaluation.
Common Diseases & Disorders
| Condition | Description | Common Causes / Risk Factors | CNA Considerations |
|---|---|---|---|
| Hypertension | Persistently elevated blood pressure, increasing strain on the heart and blood vessels | Aging, genetics, high sodium intake, obesity, inactivity, kidney disease | Measure and report blood pressure according to the care plan; report concerning readings or symptoms |
| Hypotension | Abnormally low blood pressure, sometimes reducing tissue perfusion | Dehydration, blood loss, medications, heart problems, severe infection | Observe dizziness, weakness, fainting, and changes in consciousness |
| Orthostatic Hypotension | Blood pressure drops when standing or changing to a more upright position | Dehydration, medications, prolonged bed rest, autonomic dysfunction | Assist with position changes and report dizziness or fainting |
| Atherosclerosis | Plaque buildup in artery walls that narrows vessels and restricts blood flow | High LDL cholesterol, smoking, diabetes, hypertension, genetics | Observe changes in circulation, activity tolerance, and symptoms; report concerns |
| Coronary Artery Disease (CAD) | Narrowing or blockage of coronary arteries, reducing blood supply to heart muscle | Atherosclerosis, smoking, diabetes, hypertension, high cholesterol | Report chest discomfort, unusual shortness of breath, and reduced activity tolerance |
| Myocardial Infarction (Heart Attack) | Damage or death of heart muscle due to prolonged interruption of blood supply | Usually rupture or erosion of coronary plaque with clot formation | Recognize chest discomfort, shortness of breath, sweating, nausea, or sudden weakness; activate emergency response |
| Arrhythmias / Dysrhythmia (e.g., Atrial Fibrillation) | Abnormal heart rhythms that may be too fast, too slow, or irregular | Age-related conduction changes, heart disease, hypertension, thyroid disorders | Observe irregular pulse, palpitations, dizziness, weakness, or fainting; report promptly |
| Varicose Veins / Chronic Venous Insufficiency | Enlarged superficial veins or impaired venous return, commonly affecting the legs | Weak or damaged venous valves, age, prolonged standing, pregnancy, obesity | Observe swelling, skin changes, and discomfort; follow prescribed mobility or leg-elevation plans |
| Aneurysm | Abnormal localized dilation of a weakened artery wall, which may rupture | Smoking, hypertension, atherosclerosis, genetics, certain connective tissue disorders | Report sudden severe chest, back, or abdominal pain and activate emergency response when indicated |
| Angina | Chest discomfort caused by insufficient oxygen delivery to the heart muscle, usually during exertion or stress. Does not necessarily indicate permanent heart damage. | Coronary artery disease, atherosclerosis, coronary artery spasm; risk increased by smoking, hypertension, diabetes, and high cholesterol | Report chest discomfort immediately. New, severe, persistent, or worsening symptoms require emergency response according to facility protocol. |
| Heart Failure (CHF) | The heart cannot pump or fill effectively, potentially causing fluid accumulation in the lungs and peripheral tissues. | Coronary artery disease, previous heart attacks, hypertension, heart valve disease, cardiomyopathy, arrhythmias | Observe and report dyspnea, orthopnea, edema, rapid weight gain, fatigue, and changes in activity tolerance. Follow prescribed fluid, positioning, and monitoring plans. |
| Peripheral Artery Disease (PAD) | Reduced arterial blood flow to the limbs, usually the legs | Atherosclerosis, smoking, diabetes, high cholesterol, hypertension | Report leg pain with walking, cool extremities, color changes, or poorly healing arterial wounds |
Important: CNAs observe and report cardiovascular abnormalities rather than independently diagnosing conditions, adjusting medications, or determining treatments.
Important Distinctions
- Arteriosclerosis vs. Atherosclerosis: Arteriosclerosis is a broad term for arterial thickening or hardening. Atherosclerosis specifically involves plaque buildup within artery walls and is one form of arteriosclerosis.
- Angina vs. Myocardial Infarction: Angina is a symptom of temporary myocardial ischemia, typically without heart muscle death. Myocardial infarction involves heart muscle injury or death caused by prolonged ischemia. New chest discomfort requires prompt evaluation; CNAs should not attempt to distinguish these conditions independently.
- Peripheral Artery Disease vs. Chronic Venous Insufficiency: PAD reduces arterial blood delivery to tissues and can produce cool extremities or arterial ulcers. Chronic venous insufficiency impairs blood return and can cause edema, skin discoloration, and venous stasis ulcers.
- Heart Failure vs. Heart Attack: Heart failure involves impaired pumping or filling of the heart. A heart attack causes acute heart muscle injury due to insufficient blood supply. A heart attack can lead to heart failure.
When to Report
- Blood pressure or pulse outside prescribed parameters.
- New dizziness, weakness, or fainting.
- New or worsening swelling of the legs or feet.
- Unusual shortness of breath, fatigue, or reduced activity tolerance.
- New irregular pulse or palpitations.
- Changes in skin color, temperature, or circulation.
- Unexplained bruising or bleeding.
- Sudden weight gain in a resident being monitored for fluid retention.
Emergency signs: New chest pain or pressure, severe breathing difficulty, sudden one-sided weakness, loss of consciousness, or sudden severe chest, back, or abdominal pain require immediate emergency response.
Study Notes
- Blood Pressure
- Cardiac Output
- Systemic Vascular Resistance
- Effects of Aging - Systems & Clinical Implications
Clinical Connections
- Hypertension: Persistent elevation of arterial blood pressure can increase cardiovascular risk.
- Hypotension: Low blood pressure may reduce tissue perfusion.
- Orthostatic Hypotension: Postural blood pressure changes can contribute to dizziness and falls.
- Blood Loss: Reduced circulating blood volume can impair tissue perfusion.
- Dehydration: Fluid loss can contribute to low blood pressure and an increased heart rate.
- Vital Signs: Blood pressure and pulse provide important cardiovascular observations.
- Fall Risk: Dizziness, fainting, and impaired circulation can increase fall risk.
- Recognizing Patient Distress: Chest discomfort and sudden circulation changes may signal emergencies.
Questions
- What are the four chambers of the heart?
- How do the right and left sides of the heart differ?
- What is the correct sequence of blood flow through the heart and lungs?
- What distinguishes arteries, veins, and capillaries?
- Why do pulmonary arteries carry oxygen-poor blood?
- What are the functions of red blood cells, white blood cells, and platelets?
- What is the difference between systole and diastole?
- How are heart rate, stroke volume, and cardiac output related?
- What causes blood pressure to change?
- How does aging affect arterial stiffness and cardiac reserve?
- What distinguishes atherosclerosis from arteriosclerosis?
- How do hypertension, heart failure, and coronary artery disease differ?
- Why can orthostatic hypotension increase fall risk?
- What cardiovascular symptoms require immediate emergency response?
Sources
- CNA Module 13 — Anatomy, Physiology & Aging
- National Institute on Aging — Heart Health and Aging
- MedlinePlus — Aging Changes in the Heart and Blood Vessels
- American Heart Association — Cardiovascular Disease
Flashcards
Which side of the heart pumps blood to the lungs?01-foundations / anatomy-physiology / cardiovascular
Right side.
Which side of the heart pumps oxygen-rich blood to the body?01-foundations / anatomy-physiology / cardiovascular
Left side.
What is the function of the atria?01-foundations / anatomy-physiology / cardiovascular
Receive blood returning to the heart.
What is the function of the ventricles?01-foundations / anatomy-physiology / cardiovascular
Pump blood out of the heart.
What is the correct pathway of blood through the heart and lungs?01-foundations / anatomy-physiology / cardiovascular
Right atrium → right ventricle → lungs → left atrium → left ventricle → body.
What is the difference between arteries and veins?01-foundations / anatomy-physiology / cardiovascular
Arteries carry blood away from the heart; veins return blood to the heart.
Where do gases, nutrients, and wastes exchange between blood and tissues?01-foundations / anatomy-physiology / cardiovascular
Capillaries.
Which blood cells transport oxygen?01-foundations / anatomy-physiology / cardiovascular
Red blood cells using hemoglobin.
What is the primary function of platelets?01-foundations / anatomy-physiology / cardiovascular
Help form blood clots to stop bleeding.
What is the difference between systole and diastole?01-foundations / anatomy-physiology / cardiovascular
Systole is ventricular contraction; diastole is ventricular relaxation and filling.
How does aging commonly affect the cardiovascular system?02-mechanisms / anatomy-physiology / cardiovascular
Increased arterial stiffness, reduced cardiac reserve, and less efficient blood pressure regulation.
What is orthostatic hypotension?01-foundations / anatomy-physiology / cardiovascular
A drop in blood pressure when standing or becoming more upright.
What is atherosclerosis?01-foundations / anatomy-physiology / cardiovascular
Plaque buildup in arterial walls that can restrict blood flow.
What is the difference between coronary artery disease and a heart attack?02-mechanisms / anatomy-physiology / cardiovascular
CAD restricts coronary blood flow; a heart attack causes heart muscle injury from prolonged ischemia.
What is heart failure?01-foundations / anatomy-physiology / cardiovascular
The heart cannot pump or fill effectively enough to meet the body's needs without elevated pressures.
What is atrial fibrillation?01-foundations / anatomy-physiology / cardiovascular
An irregular heart rhythm that increases the risk of blood clots and stroke.
What should a CNA do if a resident develops new chest pain or pressure?03-application / anatomy-physiology / cardiovascular
Activate the facility's emergency response and summon immediate help.