Respiration Physiology

Question 1

Respiration

Answer 1

Breathing and the exchange of gases through the lungs
- Inhale 21% O
- Exhale 17% O - inefficient system, only using 4% of O taken into system
Oxygen is the limiting factor to exercise

Question 2

Structure of the Lungs

Answer 2

Intake air at nostrils, travel through sinuses, down trachea, into right and left bronchus
- Trachea has cartilage rings that act as support to prevent collapse due to changing pressure gradients while breathing
Bronchus splits into ever-smaller branches till it forms small sack - alveoli - that facilitate gas exchange between lungs and capillaries surrounding the lungs

Question 3

Alveoli

Answer 3

Where gas exchange takes place in the lungs

- Very thin capillaries lay along the surface, trading CO2 from the body for O2 from the air

Question 4

Exercise-Induced Pulmonary Hemorrhage

Answer 4

(EIPH)
When the pressure from the right side of the heart is too great, it can cause the capillaries along the alveoli to burst. Blood leaks into the lungs and makes its way up the trachea and out the nose

Question 5

Ventilation Measurements

Answer 5

Ve = Vt x Fr

• Ve = total expiration volume (L/min)
• Vt = tidal volume - depth of breath, using 10% of lung or 80% of lung? (L)
• Fr = frequency of breaths (min)

Question 6

At Rest Breathing Rates

Answer 6

Ve = 60-80 L/min
Vt = ~4-5L
Fr = ~12-16 breaths/min

Question 7

Passive and Active Diffusion

Answer 7

Passive diffusion - breathing alone
Active diffusion - physically pulling the into the lungs and forcing it out again
- Allows horse to breath around maximum capacity and retain air in the lungs

Question 8

Respiration Limits

Answer 8

Airway resistance - affected by size and diameter

Airflow - increases as resistance decreases and pressure increases

Question 9

Airflow Equation

Answer 9

Airflow = (P1 - P2) / resistance
P1 - pressure at the bottom of the lungs
P2 - pressure of environment

Question 10

Equine COPD, “Heaves”

Answer 10

Condition where the horse is extremely sensitive to allergens, pollutants, dust, etc. and airway will respond to presence by constricting and increasing mucous production

• Prevention - hay soaking, remain outside, etc.
• Treatment - clenbuterol - beta-agonist like adrenaline, causes dilation of trachea to combat constriction
• • may also cause tremors and increase HR

Question 11

Affects of Exercise

Answer 11

Increase respiration rate - 10x as much

- the more fit the horse, though, the less the respiration rate increases

Question 12

Respiration and Stride

Answer 12

Respiration follows the motion of the horse’s stride. As he reaches forward, inspire (with head high and guts shifting backwards). As he contracts and pulls limbs back together, exhales (with head lowered and guts shifting forwards).

Question 13

Oxygen Delivery

Answer 13

In RBC, oxygen is carried by hemoglobin
Through perfusion (transfer) the oxygen is passed to muscles and organs
Through loading, hemoglobin moves O2 to myoglobin in the muscles