1. What physiological systems are involved in make the exercising horse and athlete? EXERCISE PHYSIOLOGY

2. RESPIRATORY SYSTEM Function - Exchange oxygen and carbon dioxide Oxygen is used for tissues Carbon dioxide is released by those tissues Air passes through the trachea to bronchi Alveoli Functional units where gas exchange occurs During inspiration Diaphragm and intercostal muscles expand the chest, allowing air to flow in The amount of air inspired or expired during a normal breath is referred to as Tidal Volume

3. RESPIRATORY SYSTEM During exercise, tissues needs for oxygen increases Minute volume must increase From about 150 L/min to 1500 L/min (during fast gallop) At a gallop, respiration rate and stride rate are coupled in a 1:1 ratio Expiration occurring when from limbs make ground contact

4. RESPIRATORY DISORDERS EIPH Exercise Induced Pulmonary Hemorrhage Presence of blood in the respiratory tract after exercise Referred to as “bleeders” Laryngeal Hemiplegia Dysfunctional larynx due to nerve damage Can be treated surgically COPD Chronic Obstructive Pulmonary Disease Commonly called “heaves” Inflammation of the bronchioles Caused by moldy hay or straw

5. CARDIOVASCULAR SYSTEM Consists of blood, a series of tubes (blood vessels) through which the blood flows, and a heart which creates the flow of blood Blood is composed of Red Blood Cells Erythrocytes White Blood Cells Leukocytes Platelets Cellular elements are called plasma Adult horse (1000lbs) contains approx 50 L (13.2 gal) of blood

6. CARDIOVASCULAR SYSTEM Cardiac Output (CO) Measure of how much blood the heart can pump per minute Product of heart rate (HR) times stroke volume (SV) HR: 25 – 45 Beats/min Average around 32 – 35 Max 220 – 250 beats/min

7. MUSCULAR SYSTEM 3 Categories Smooth Involuntary & automatic contractions Cardiac Involuntary & automatic contractions Skeletal Voluntary & functions in movement of the horse

8. MUSCULAR SYSTEM Skeletal Muscle Striated in design Composed of numerous muscle bundles Which make up muscle fibers Contain several hundred to several thousand contractile filaments Responsible for muscle contraction

9. MUSCLE FIBERS Type I Slow-contracting fibers Low ability to oxidize glucose or glycogen rapidly Fatigue resistant Utilize fuels in the presence of oxygen Long term use Nonstrenuous work Provide endurance

10. MUSCLE FIBERS Type II Fast contracting fibers Fatigue more quickly High glycolytic activity (use glycogen as energy) Classified as Type IIA Type IIB Type IIC According to myosin structure