Cardiovascular

Cardiovascular System Overview

Structure & Function of the Heart

  • The cardiovascular system comprises the heart and blood vessels whose functions include circulating blood, providing oxygen and nutrients, and removing waste products.

Location of the Heart

  • Heart Location:

    • Located in the middle of the chest, between the lungs, behind and slightly to the left of the sternum.

Size of the Heart

  • Approximate Size:

    • About the size of a fist.

    • Blood vessels extend throughout the body, forming a network that is as tall and wide as the individual.

Weight of the Heart

  • Heart Weight:

    • Estimated to weigh between 8 ounces and 12 ounces.

    • The weight can vary based on factors such as gender, body weight, and diseases.

Anatomy of the Heart

  • The heart contains four chambers:

    1. Right Atrium: Receives deoxygenated blood from the body.

    2. Left Atrium: Receives oxygenated blood from the lungs.

    3. Right Ventricle: Pumps blood to the lungs for oxygenation.

    4. Left Ventricle: Pumps oxygenated blood to the rest of the body.

Heart Valves and Blood Flow

  • Key Components:

    • Valves: Pulmonary valve, Tricuspid valve, Mitral valve, Aortic valve.

    • Blood flows through the four hollow chambers and valves to maintain one-way circulation.

Blood Circulation Processes

  • Two Main Processes:

    1. Pulmonary Circulation: Deoxygenated blood enters the right side of the heart, is sent to the lungs where it gets oxygenated, and returns to the left side of the heart.

    2. Systemic Circulation: Oxygenated blood is pumped from the left side of the heart to body tissues, delivering oxygen and nutrients and returning deoxygenated blood to the right side of the heart.

Structure of the Cardiovascular System

  • The heart connects to a vast network of blood vessels, which help circulate blood throughout the body.

Types of Blood Vessels

  • Three Major Types:

    1. Arteries: Carry blood away from the heart, usually oxygenated (except for the pulmonary artery).

    • Examples: Aorta (largest artery), arterioles (smallest branches).

    1. Veins: Return blood to the heart, usually deoxygenated (except for pulmonary veins).

    • Main veins: Inferior and Superior vena cava.

    1. Capillaries: Tiny vessels where gas exchange and nutrient transfer occur, enabling waste removal from tissues.

Blood Vessel Structure

  • Arteries: Thicker walls than veins due to more smooth muscle and elastic tissues, allowing them to handle high pressure and expand with blood flow.

  • Veins and Venules: Thinner walls with less muscle and elastic tissue while larger in diameter relative to arteries.

  • Capillaries: Allow the exchange of materials between blood and tissues.

Heart Conduction System

  • Specialized nerve tissue responsible for generating and conducting electrical impulses, initiating heart contractions.

    • The Sinoatrial (SA) Node serves as the natural pacemaker of the heart.

Age-Related Changes in Cardiovascular Function

  • In older adults:

    • Decreased blood movement leads to slower circulation.

    • Energy levels may decline.

    • Recovery from illness is delayed.

    • Increased risk of edema due to reduced circulation.

    • Arterial hardening and loss of elasticity can occur, increasing risks of hypertension and related complications.

Vital Signs: Blood Pressure & Pulse

  • Vital signs indicate normal body functions and can signal life-threatening events.

Blood Pressure (BP)

  • Definition: The force exerted by circulating blood against vessel walls.

  • Components:

    • Systolic Pressure: Force needed to pump blood out of the heart.

    • Diastolic Pressure: Pressure in the arteries when the heart is at rest.

  • Classification of BP:

    • Healthy: Less than 120/80 mm Hg

    • Elevated: 120-129/<80 mm Hg

    • Stage 1 Hypertension: 130-139/80-89 mm Hg

    • Stage 2 Hypertension: ≥140/≥90 mm Hg

    • Hypertensive Crisis: >180/>120 mm Hg

  • Accuracy in measuring and recording blood pressure is essential for patient health monitoring.

Methods for Taking Blood Pressure

  • Ensure patient is rested, seated, and comfortable.

  • Validate cuff placement above the elbow and maintain proper arm position at heart level.

  • Avoid caffeine, smoking, or stress prior to measurement.

Pulse Measurement

  • Definition: Measure of heart rate, indicating heart rhythm and strength.

  • Normal Pulse Rate: 60 to 100 beats per minute in healthy adults.

  • Rhythm variations may occur due to exercise, emotions, and health conditions.

  • Resting Heart Rate:

    • Varies by age: ~60-80 bpm for adults, higher for children.

Blood Composition

  • Types of Blood Cells:

    1. Red Blood Cells (Erythrocytes): Carry oxygen and carbon dioxide, containing hemoglobin.

    2. White Blood Cells (Leukocytes): Part of the immune response; includes monocytes, basophils, eosinophils, lymphocytes, and neutrophils.

    3. Platelets (Thrombocytes): Essential for blood clotting, activated by injury to the blood vessel walls.

Blood Composition Breakdown

  • Plasma: 55% of blood, containing water, proteins, nutrients, and hormones.

  • Red blood cells: Approximately 45%.

  • White blood cells and platelets: Less than 1%.

Common Cardiovascular Disorders

  • Heart Disease: General term that includes various conditions such as:

    • Coronary artery disease

    • Heart failure

    • Arrhythmia

    • Peripheral vascular disease

    • Cardiomyopathy

  • Risk Factors: Include smoking, high cholesterol, diabetes, high blood pressure, obesity, and physical inactivity.

Specific Condition Description

  • Angina Pectoris:

    • A condition marked by recurring chest pain due to inadequate blood flow to the heart.

    • It can signify risk for myocardial infarction (heart attack).

  • Myocardial Infarction (Heart Attack):

    • Results from a blockage in blood flow to the heart, causing tissue death due to lack of oxygen.

  • Congestive Heart Failure:

    • The heart is unable to pump sufficient blood to fulfill body demands, leading to symptoms like shortness of breath, fatigue, and swelling.

Risk Management Strategies

  • Importance of early detection and treatment,

  • Lifestyle changes such as balanced diet, regular exercise, and stress management.

  • Recognizing signs of heart complications to prevent severe outcomes.