Respiratory Functions
Name the primary function of the lungs
To facilitate gas exchange – oxygen in, carbon dioxide out.
What are the muscles involved in inspiration?
Diaphragm and external intercostal muscles.
What happens to respiratory rate during exercise?
Increases
What is gaseous exchange?
Swapping oxygen and carbon dioxide in lungs.
What increases oxygen demand during exercise?
Working muscles need more oxygen to produce energy.
What happens to the diaphragm during inhalation?
It contracts and moves downward.
What is tidal volume?
The volume of air breathed in or out per breath.
Define ventilation and how it changes during exercise.
Ventilation = RR × TV; it increases to meet O2 needs.
What is diffusion in the lungs?
Movement of gases from high to low concentration across membranes.
Define a-vO2 difference.
The difference in O2 concentration between arteries and veins.
Describe the pathway of air from nose to alveoli.
Nose → pharynx → larynx → trachea → bronchi → bronchioles → alveoli.
Explain how pressure changes allow air to move in and out of lungs.
Air moves from high to low pressure—lungs expand during inhalation, contract during exhalation.
Explain the term 'steady state' in respiratory terms.
When oxygen supply = oxygen demand and variables plateau.
How does exercise impact diffusion rate?
Increased blood flow and lung expansion improve diffusion.
How is oxygen supply matched to oxygen demand?
By increasing RR, TV, cardiac output, and vasodilation in working muscles.
Compare RR at rest vs. during exercise?
RR increases during exercise to meet O2 demand.
What happens to intercostal muscles during exercise?
They contract more forcefully to allow deeper breaths.
What is the acute response of tidal volume to submaximal exercise?
It increases to bring in more air per breath.
What causes an increase in a-vO2 diff during exercise?
Greater extraction of O2 due to increased muscle demand.
What does it mean when someone reaches steady state?
Physiological balance where O2 supply meets 02 demand.
Explain how the respiratory system supports energy production during intense exercise.
It increases oxygen intake and carbon dioxide removal to meet muscular demands. (Diffusion rate). Circulates more O2 to the muscles during exercise.
Describe how mechanics of breathing adapt to increased exercise intensity.
Increased activation of muscles to support greater volume of air movement in and out of the lungs.
Describe how the respiratory system responds acutely to maximal exercise.
Rapid increase in RR, TV and V to supply more oxygen to muscles. TV eventually plateaus at maximal intensity meaning that RR would need to increase further to increase total V
How does the body optimize oxygen delivery to muscles during intense activity?
Through increased cardiac output and V. Increase in RR, TV and HR as well as SV to meet the new demand for oxygen.
Explain what occurs at oxygen deficit and compare that to what occurs during EPOC.
Oxygen Deficit occurs at the start of exercise when the body’s oxygen demand exceeds its oxygen supply. During this time, the cardiovascular and respiratory systems haven't yet fully adjusted to the increased energy demands.
In contrast, EPOC (Excess Post-exercise Oxygen Consumption) occurs after exercise, when the body’s oxygen consumption remains elevated above resting levels. This extra oxygen is used to:
Replenish phosphocreatine (PC) stores
Remove lactate & H+
Restore oxygen levels in the blood and muscles
Help remove excess Co2