Heart Anatomy and Structures

• The tricuspid valve is located between the right atrium and right ventricle
• The aortic semilunar valve is between the left ventricle and aorta
• The mitral valve sits between the left atrium and left ventricle
• The pulmonary valve is located between the right ventricle and pulmonary trunk

Heart Structures

• Key internal and external heart structures include:
  • Right atrium
  • Pulmonary valve
  • Tricuspid valve
  • Right ventricle
  • Left atrium
  • Mitral valve
  • Chordae tendineae
  • Left ventricle
  • Papillary muscle
  • Aortic valve
  • Superior and Inferior vena cava
  • Aorta
  • Right and Left pulmonary artery
  • Pulmonary trunk
  • Right and Left pulmonary veins

ECG Diagram

• The ECG diagram consists of the P wave, QRS wave, and T wave

Artery Structure

• Arteries are strong, elastic vessels carrying blood away from the heart under high pressure
• Arteries have three distinct layers: tunica interna, tunica media, and tunica externa
  • Tunica interna: Innermost layer
    • Made of simple squamous epithelium (endothelium)
    • Provides a smooth surface and prevents clotting
  • Tunica media: Middle layer
    • Bulk of the arterial wall
    • Contains smooth muscle cells and a thick layer of elastic connective tissue
  • Tunica externa: Outer layer
    • Thin connective tissue layer with irregular elastic and collagen fibers
    • Attaches the artery to surrounding tissues

Hypertension Risk Factors

• High stress levels
• High sodium diets
• Low physical activity levels
• Obesity

Angina Pectoris

• Blockage of a coronary artery branch causes decreased blood flow to myocardial cells
• Lack of oxygen results in the painful condition angina pectoris

Abdominal Aorta

• The abdominal aorta divides into the right and left common iliac arteries

Pulmonary Circuit

• Oxygen-poor blood travels via the pulmonary circuit to the lungs
• The blood picks up oxygen and releases carbon dioxide in the lungs

Cardiovascular System

• The cardiovascular system includes the heart and blood vessels

Capillaries

• Capillaries are small blood vessels connecting arterioles and venules for nutrient and waste exchange
• Walls of capillaries are semipermeable; opening size varies by tissue

Cardiac Impulse Sequence

• SA node → AV node → AV bundle → Purkinje fibers

Bradycardia

• Bradycardia is an abnormally slow heart beat

Heart Valves

• Atrioventricular (AV) valves (tricuspid and mitral) close when the ventricles contract
• Semilunar valves (pulmonary and aortic) open during ventricular contraction

Myocardium Blood Supply

• The coronary arteries are responsible for bringing blood to the myocardium

Blood Flow Through the Heart

• Right atrium → right ventricle → pulmonary artery → lungs → pulmonary veins → left atrium → left ventricle → aorta

Blood Composition

• The average human has ~5 liters of blood
• Plasma accounts for 55% of blood volume
  • Plasma consists of 92% water, 7% protein, and 1% other solutes
  • Most plasma proteins are produced by the liver, except gamma globulins, which are produced by lymphatic tissues

White Blood Cell Abundance

• Lymphocytes: 25-33%
• Neutrophils: 54-62%
• Eosinophils: 1-3%
• Basophils: <1%
• Monocytes: 3-9%

Leukemia and Bleeding

• A low platelet count (thrombocytopenia) can cause bleeding in leukemia patients

Red Blood Cells

• Red blood cells (erythrocytes) are biconcave discs
• Biconcave shape increases surface area for transportation and reduces diffusion distance
• Mature RBCs lack nuclei to maximize space for hemoglobin

Blood Coagulation

• Thrombin serves as the blood coagulation mechanism

Hemoglobin and Oxygen

• Iron is the element in hemoglobin that binds to oxygen

Plasma Electrolytes

• Sodium and Chloride

Universal Blood Donor

• Blood type O- is the universal donor

Blood Type AB

• Blood type AB has both antigens A and B on the surface of RBCs

Red Blood Cell Production

• RBCs are produced in the bone marrow

Common Blood Type

• The most common blood type in the United States is O+

White Blood Cell Count

• A normal white blood cell count is between 3,500 to 10,500

Sickle Cell Disease

• Sickle cell disease is an inherited disease

Blood Composition of Red Blood Cells

• Blood is generally 45% red blood cells

Hematocrit

• Hematocrit (HCT) is the percentage by volume of red blood cells in a sample of whole blood

Lymphocytes

• Lymphocytes are white blood cells that provide immunity
• Lymphocytes produce antibodies against foreign substances

Tissue Type

• Blood is considered Connective tissue