Sports Sci Final

2.1 Structure and Function of the Ventilatory System

2.1.1 Principal Structures of the Ventilatory System

  • Nasal cavity: Filters, warms, and humidifies incoming air.

  • Pharynx: Passageway for air, connecting nasal cavity to larynx.

  • Larynx: Contains vocal cords and protects lower airways.

  • Trachea: Windpipe that conducts air to the bronchi.

  • Bronchi: Two main airways branching into the lungs.

  • Bronchioles: Smaller branches of the bronchi within the lungs.

  • Alveoli: Air sacs where gas exchange occurs.

  • Lungs: Organs for gas exchange; right lung has three lobes, left lung has two.

  • Diaphragm: Muscle responsible for ventilatory movement.

2.1.3 Definitions of Key Ventilation Terms

  • Pulmonary Ventilation: Movement of air into and out of the lungs (breathing).

  • Total Lung Capacity (TLC): Maximum volume of air the lungs can hold.

  • Vital Capacity (VC): Maximum amount of air exhaled after a full inhalation.

  • Tidal Volume (TV): Volume of air inhaled or exhaled during normal breathing.

  • Expiratory Reserve Volume (ERV): Additional air exhaled after normal exhalation.

  • Inspiratory Reserve Volume (IRV): Additional air inhaled after normal inhalation.

  • Residual Volume (RV): Air remaining in lungs after maximum exhalation.

2.1.4 Mechanics of Ventilation in the Human Lungs

  • Inhalation (Inspiration):

    • Diaphragm contracts and moves downward.

    • Intercostal muscles contract, expanding the rib cage.

    • Thoracic cavity volume increases, pressure decreases, air flows in.

  • Exhalation (Expiration):

    • Diaphragm relaxes and moves upward.

    • Intercostal muscles relax, shrinking the rib cage.

    • Thoracic cavity volume decreases, pressure increases, air flows out.

2.1.6 Role of Hemoglobin in Oxygen Transport

  • Hemoglobin: Protein in red blood cells that binds to oxygen.

  • Function:

    • Transports oxygen from the lungs to tissues.

    • Carries carbon dioxide from tissues to the lungs for exhalation.

    • Facilitates oxygen release where it’s needed due to changes in pressure and pH.

2.1.7 Gaseous Exchange at the Alveoli

  • Process:

    • Oxygen diffusion: From alveoli (high O₂ concentration) into capillaries (low O₂ concentration).

    • Carbon dioxide diffusion: From capillaries (high CO₂ concentration) into alveoli (low CO₂ concentration) for exhalation.

  • Structure supporting exchange:

    • Thin alveolar walls for short diffusion distance.

    • Extensive capillary network for gas transport.

    • Moist surfaces for efficient diffusion.

2.2 Structure and Function of the Cardiovascular System

2.2.1 Composition of Blood

  1. Plasma: Liquid component carrying nutrients, hormones, and waste products.

  2. Erythrocytes (Red Blood Cells): Contain hemoglobin to transport oxygen and carbon dioxide.

  3. Leucocytes (White Blood Cells): Defend against infection and foreign substances.

  4. Platelets: Small cell fragments involved in blood clotting.

2.2.2 Functions of Blood Components

  • Erythrocytes: Transport oxygen and carbon dioxide.

  • Leucocytes: Immune response; defend against pathogens.

  • Platelets: Form clots to prevent blood loss.

2.2.3 Anatomy of the Heart

  • Chambers:

    • Atria (Right and Left): Upper chambers receiving blood.

    • Ventricles (Right and Left): Lower chambers pumping blood out.

  • Valves:

    • Atrioventricular Valves: Tricuspid (right), Bicuspid/Mitral (left).

    • Semilunar Valves: Pulmonary valve (right), Aortic valve (left).

  • Major Blood Vessels:

    • Superior and Inferior Vena Cava: Bring deoxygenated blood to the right atrium.

    • Pulmonary Arteries: Carry deoxygenated blood from the right ventricle to the lungs.

    • Pulmonary Veins: Carry oxygenated blood from the lungs to the left atrium.

    • Aorta: Distributes oxygenated blood from the left ventricle to the body.