Circulatory System: Electrical Conduction System

Circulatory System

• The electrical conduction system consists of:
  • SA Node (Sinoatrial Node): generates electrical impulses to trigger heartbeat
  • AV Node (Atrioventricular Node): relays electrical impulses from SA Node to Ventricles
  • Bundle of His: specialized fibers that carry electrical impulses to Ventricles
  • Bundle Branches: divide the Bundle of His into left and right branches
  • Purkinje Fibers: conduct electrical impulses to Ventricular muscle cells
• Healthy Blood pressure: 120/80 mmHg
• Hypertension: 140/90 mmHg or higher
• Hypotension: 90/60 mmHg or lower
• Main blood cells:
  • Red Blood Cells (RBCs): carry oxygen from lungs to body tissues
  • White Blood Cells (WBCs): part of immune system, fight infections
  • Platelets: involved in blood clotting

Blood Vessels

• Arteries:
  • Carry oxygenated blood away from heart to body tissues
• Veins:
  • Carry deoxygenated blood back to heart
• Capillaries:
  • Allow exchange of oxygen and nutrients for carbon dioxide and waste products

Blood Flow

• Steps of blood flow:
  • Heart (Right Ventricle) → Pulmonary Artery → Lungs → Pulmonary Veins → Heart (Left Atrium) → Aorta → Systemic Circuit → Capillaries → Venules → Veins → Heart (Right Atrium)

Blood Type and Anemia

• Universal donor: Type O negative (can be transfused to anyone)
• Universal recipient: Type AB positive (can receive blood from anyone)
• Low red blood cells: Anemia

Heart Structures

• 4 chambers: Right Atrium, Right Ventricle, Left Atrium, Left Ventricle
• 4 valves: Tricuspid, Pulmonary, Mitral, Aortic
• 2 arteries: Aorta, Pulmonary Artery
• 2 veins: Superior and Inferior Vena Cava

Respiratory System

• Roles of the Respiratory System:
  • Moves air containing oxygen into lungs
  • Removes carbon dioxide from lungs
  • Provides surface area for gas exchange into cells
• Oxygen is needed for cellular respiration (energy production)

Respiratory Process

• Steps of the respiratory system:
  • Nose: filters, warms, and humidifies air
  • Pharynx (throat): air passes through on its way to lungs
  • Larynx (voicebox): air passes through on its way to lungs
  • Trachea: divided into right and left bronchi
  • Bronchi: air passages that move air into lungs
  • Alveoli: gas exchange occurs

Respiratory Values

• Tidal Volume: volume of air inhaled or exhaled per breath
• Respiratory minute volume: total volume of air inhaled per minute
• Vital Capacity (FVC): maximum volume of air exhaled after maximum inhalation
• FEV1: maximum volume of air exhaled in 1 second
• Values same for both men and women: Respiratory rate, Tidal Volume

Obstructive Disorder

• Definition: a condition where airflow is partially or completely blocked
• Examples: Asthma, Chronic Obstructive Pulmonary Disease (COPD)