Chapter 20 Heart and Neck Vessels

Cardiovascular System Overview

  • Components: Heart (muscular pump) and blood vessels.

  • Precordium: Area on the anterior chest overlying the heart and great vessels.

Heart Anatomy

  • Heart Location: Between lungs in the mediastinum; extends from 2nd to 5th intercostal space.

  • Heart Orientation: Right side is anterior; left side mostly posterior.

  • Chambers: Four in total (Right Atrium, Right Ventricle, Left Atrium, Left Ventricle).

  • Vascular Connections:

    • Superior/Inferior Vena Cava: Return unoxygenated blood to the right heart.

    • Pulmonary Arteries: Carry venous blood to the lungs.

    • Pulmonary Veins: Return oxygenated blood to the left heart.

    • Aorta: Distributes oxygenated blood to the body.

Heart Wall Layers

  • Pericardium: Tough double-walled sac; contains pericardial fluid.

  • Myocardium: Muscular wall responsible for pumping.

  • Endocardium: Lining of heart chambers and valves.

Cardiac Cycle

  1. Diastole: Ventricles relax and fill with blood (2/3 of cycle).

  2. Systole: Ventricles contract to pump blood (1/3 of cycle).

    • Closure of AV valves marks S1; closure of semilunar valves marks S2.

    • Phases: Early filling, Presystole, Isometric contraction, Ejection, Isometric relaxation.

Valves

  • Atrioventricular Valves:

    • Tricuspid (right)

    • Mitral (bicuspid, left)

  • Semilunar Valves:

    • Pulmonic (right)

    • Aortic (left)

Direction of Blood Flow

  1. Unoxygenated blood: RA → RV → Pulmonary Artery → Lungs.

  2. Oxygenated blood: LA → LV → Aorta → Body.

Heart Sounds

  • S1: Closure of AV valves; heard best at the apex.

  • S2: Closure of aortic and pulmonic valves; heard best at the base.

  • Extra Sounds: S3 (ventricular filling) and S4 (atrial contraction) can indicate pathology.

Jugular Veins and Carotid Artery Assessment

  • Jugular Pulse: Reflects right heart activity; distension indicates heart failure.

  • Carotid Pulse: Represents systemic circulation; palpate with caution.

Cardiac Output

  • Normal Range: 4-6 L/min; influenced by preload and afterload.

  • Preload: Volume of blood; affected by venous return.

  • Afterload: Resistance against which the heart must pump.

Developmental Competence

  • Pregnancy: Increased blood volume and heart rate.

  • Children: Heart begins to function at the end of 3 weeks’ gestation; undergoes anatomical changes postnatally.

  • Older Adults: Increased systolic BP, decreased maximum heart rate, risk of heart disease rises.

Summary of Health Promotion

  • Monitor BP and cholesterol: Regular checks; manage lifestyle risks.

  • Smoking cessation: Critical to heart health.

  • Healthy Diet/Exercise: Reduce risk factors through lifestyle changes.