Sports Science

Describe each level in the biological hierarchy from cell to organism and give examples

• Cell: Basic unit of life (e.g., muscle cell)

• Tissue: Group of similar cells (e.g., cardiac muscle tissue)

• Organ: Structure made of tissues (e.g., heart)

• Organ system: Organs working together (e.g., circulatory system)

• Organism: Complete living being (e.g., human)

Explain how pressure changes drive ventilation in the lungs

• Inhalation: Diaphragm + external intercostals contract → thoracic cavity volume ↑ → pressure ↓ → air flows in

• Exhalation (rest): Diaphragm + external intercostals relax → volume ↓ → pressure ↑ → air flows out

• Forced exhalation: Internal intercostals + abdominals contract

Define and differentiate tidal volume, vital capacity, and residual volume.

• Tidal volume: Air in/out during normal breath

• Vital capacity: Max air exhaled after deepest inhale

• Residual volume: Air left in lungs after forced exhalation

Trace the full pathway of blood through the heart, lungs, and body.

1. Vena cava → right atrium

2. Right atrium → tricuspid valve → right ventricle

3. Right ventricle → pulmonary valve → pulmonary artery → lungs

4. Lungs → pulmonary vein → left atrium

5. Left atrium → bicuspid valve → left ventricle

6. Left ventricle → aortic valve → aorta → body

What structures control the heart’s electrical activity and contraction sequence?

• SA node (pacemaker) initiates impulse → atria contract

• Impulse → AV node → bundle of His → Purkinje fibers → ventricles contract

• Ensures atria contract before ventricles

What causes the “lub” and “dub” heart sounds?

• "Lub": Closing of atrioventricular (AV) valves (tricuspid & bicuspid) during ventricular contraction

• "Dub": Closing of semilunar valves (pulmonary & aortic) during relaxation

Compare arteries, veins, and capillaries by structure and function.

• Arteries: Thick, elastic walls; high pressure; carry blood away from heart

• Veins: Thin walls, valves to prevent backflow; carry blood to heart

• Capillaries: One cell thick; site of gas/nutrient exchange

What are the four main components of blood and their functions?

• Plasma: Carries nutrients, hormones, waste

• Red blood cells (RBCs): Transport oxygen via hemoglobin

• White blood cells (WBCs): Fight infection

• Platelets: Help with clotting

How does partial pressure influence oxygen and carbon dioxide movement in the lungs?

• O₂ diffuses from alveoli (high PO₂) → blood (low PO₂)

• CO₂ diffuses from blood (high PCO₂) → alveoli (low PCO₂)

• Movement is from high to low partial pressure

Distinguish between simple and facilitated diffusion, and give an example of each.

• Simple diffusion: Molecules move directly across membrane (e.g., O₂ into cells)

• Facilitated diffusion: Uses protein channels (e.g., glucose via GLUT transporters)

What happens to cells in hypotonic, isotonic, and hypertonic solutions?

• Hypotonic: Water enters cell → cell swells or bursts

• Isotonic: No net movement → cell maintains size

• Hypertonic: Water exits cell → cell shrinks (crenation)

How does exercise affect respiratory volumes and ventilation rate?

• Tidal volume increases to bring in more O₂

• Ventilation rate increases to meet demand

• Minute ventilation (TV × VR) increases

• Forced breathing involves additional muscles