Chapter 10 - Respiration During Exercise Flashcards
What are the two primary roles of the respiratory system?
Gas exchange between the external environment & the body (primary)
Regulation of the acid-base balance
Define: Ventilation
The MECHANICAL process of moving air in and out of the lungs.
Define: Diffusion
The random movement from an area of higher concentration to an area of lower concentration.
What are the two zones in the respiratory system?
The Conducting and Repiratory
What is the conducting zone?
It is the area that conducts the air to the respiratory system. Air is humidified and warmed in this zone.
What structures make up the conducting zone?
The Epiglottis, Trachea, Bronchi, Bronchioles, Terminal Bronchioles.
What is the respiratory zone?
It is where the exchange of gases between the air and the blood occurs.
What are the components of the respiratory zone?
Respiratory bronchioles, Aveolar ducts, Aveolar sacs.
What is Bulk Flow?
Bulk flow is the movement of particles through the conducting zone due to a pressure difference between each end.
What happens to the pressure in the chest cavity when the diaphragm moves downward?
It decreases (air moves into lungs - diffusion)
Air then moves into the lungs from a higher pressure to a lower pressure
What happens during to the diaphragm during expiration?
It relaxes
What happens to the pressure in the chest cavity during expiration?
It increases and the diaphragm relaxes.
What determines the level of resistance to airflow?
The diameter of the airway (COPD)
How are the lung volumes measured?
By using spirometry
What are the three lung volumes?
Vital Capacity
Total Lung Capacity
Residual Volume
What is vital capacity?
Maximal forced expiration after maximal inspiration
What is Total Lung Capacity?
The amount of gas in the lungs after maximal inspiration
What is Residual Volume?
The volume of gas in the lungs after maximal expiration
What is partial pressure?
The total pressure of a gas mixture is equal to the sum of the pressures that each individual gas exerts independently.
What is the Barometric pressure at sea level?
760mmHg
What is the percentage of Oxygen, Nitrogen and Carbon Dioxide in room temperature?
Oxygen - 20.93
Nitrogen - 79.04
Carbon Dioxide - 0.03
How do you calculate the partial pressure of oxygen in room air?
PO2 = 760mmHg x 0.2093 = 159mmHg
Oxygen and carbon dioxide diffuse from…
a high partial pressure to a low partial pressure between the lungs and blood and between the blood and tissues.
Blood Flow to Lung…
At rest, the rate of pulmonary circulation is equal to systemic circulation.
However, pressure is lower because of vascular resistance.
During exercise, pulmonary vascular resistance drops.
Diffusion Between Blood and Tissue:
The rate of transfer of gas - Cellular respiration
Where are oxygen levels higher? Where will oxygen diffuse? (Blood and Tissue)
Where: Blood
Diffuse: To tissue
When are carbon dioxide levels higher? Where will carbon dioxide diffuse to? (Blood and Tissue)
Where: Tissue
Diffuse: Blood
Diffusion Between Blood and Lungs:
Gas exchange in lungs
Where are the oxygen levels higher? Where will oxygen diffuse? (Blood and Lungs)
Where: Lung
Diffuse: To blood
Where are the carbon dioxide levels higher? Where will carbon dioxide diffuse?
Where: Blood
Diffuse: To lungs
How is oxygen transported in the blood?
Hemoglobin:
Oxyhemoglobin = Bound to oxygen
Deoxyhemoglobin = NOT bound to oxygen
What does the amount of oxygen transport depend on?
It is dependent on the concentration of hemoglobin
What is the Diffusion Between Blood and Tissue formula?
Vgas = A / T x D x (P1 - P2)
The Oxyhemoglobin Dissociation Curve?
The point at which we go from oxyhemoglobin to deoxyhemoglobin.
During intense exercise, venous PO2 may reach 18-20mmHg and tissues may extract up to 90% O2 on Hb
What are the several factors that affect the binding of oxygen and hemoglobin?
pH and Temperature
How does pH effect the binding of oxygen and hemoglobin?
Blood pH decreases during heavy exercise due to the production of lactic acid. This means that the blood becomes more acidic.
Increase in acidity shifts the curve to the RIGHT. This means that oxygen is more readily released from hemoglobin and given to the tissues.
What is the effect of Temperature on the binding of oxygen and hemoglobin?
An increase in the blood temperature also shifts the curve to the RIGHT and favours the release of oxygen to the tissues. (increased blood temp)
What is the BOHR effect?
The shifting of the oxyhemoglobin curve to the right.
What happens to Temperature and Acidity during exercise?
Acidity goes up (pH goes down) and Temperature increases.
This means that more oxygen is released to the muscles during exercise. It shows that the body is trying to deal with a situation to achieve homeostasis.
What is partial pressure?
The amount of oxygen that is left in the muscle tissue / taken from the blood.
What is affinity?
The strength of attraction of oxygen to hemoglobin (pH & Temp)
Carbon Dioxide Transport in Blood:
Goes from tissue to blood to lungs
What are the 3 main ways of Carbon Dioxide transport in Blood?
Dissolved in Plasma (10%)
Bound to Hemoglobin (20%)
Bicarbonate (70%)
- CO2 can be converted to bicarbonate
At the lung, the PCO2 is lower than…
it is in the blood so the carbon dioxide diffuses into the lung where it expires.
Control of Ventilation: How do we turn the system “on”?
Initially, ventilation increases rapidly. PO2 and PCO2 change just slightly and then levels are maintained.
What happens to ventilation during prolonged exercise in the heat?
It INCREASES (drifts upwards)
Why does ventilation drift upwards?
Increase in blood temperature.
Where is the respiratory control centre located?
In the medulla (the brain)
Central command is important in ventilation.
The response is then fine tuned by receptors located outside of the brain… by?
Peripheral Chemoreceptors: Aortic & Caratid bodies (heart and neck)
Skeletal Muscle:
- Spindles and Golgi Tendons
- Muscle Chemoreceptors
What is the effect of training on ventilation?
It goes down
Why may ventilation be lower following training?
We have an increased ability to bring in oxygen, carry oxygen and extract oxygen.
