Gas Exchange Flashcards
Explain how air enters the human gas exchange system
- As you breathe, air enters the trachea
- The trachea splits into two bronchi- one bronchus leading to each lung
- each bronchus then branches off into smaller tubes called bronchioles
- The bronchioles and in small air sacks called alveoli where the gas is exchanged
- The rib cage, intercostal muscles and the diaphragm all work together to move air in and out
Explain what happens during inspiration – breathing in
1- external intercostal muscles and diaphragm muscles contract
- Rib cage moves up and out and the diaphragm flatten in increasing volume of the thoracic cavity
- Lung pressure decreases
- Airflow from high-pressure to low pressure down the trachea into the lungs
Is in inspiration an active process?
Yes, it requires energy
Explain what occurs during expiration – breathing out
- external intercostal and diaphragm muscles relax
- Rib cage move down and in and diaphragm becomes curved
- Volume of thoracic cavity decreases causing air pressure to increase
- Air is forced down the pressure gradient out of the lungs
Is expiration an active process?
No, it is a passive process
And does not require energy
Explain what happens during forced expiration
External intercostal muscles relax and internal intercostal muscles contract pulling the rib cage further down and in
What is an antagonistic process?
And opposing process
There’s a large number of alveoli in the lungs. What does this mean?
There’s a big surface area for exchanging oxygen and carbon dioxide
What is the Alviola epithelium?
Each Alviola is made from a single layer of thin flat cells called alviolar epithelium
What are alveoli surrounded by?
Network of capillaries
Where does oxygen in the alveoli diffuse to?
Oxygen diffusers out of the alveoli across the alveolar epithelium into the capillary epithelium and into haemoglobin in the blood
Where does CO2 diffuse to out of the blood
Into the alveoli from the blood and his breathed out
How are alveoli adapted for gas exchange?
- thin exchange area- alveolar epithelium is only one selfie meaning there’s a short diffusion pathway
- Large surface area so the number of alveoli means there’s a large surface area for gas exchange
What concentration gradient speeds up diffusion?
Steep concentration gradient of oxygen and carbon dioxide between the alveoli and capillaries increases the rate of diffusion
What is tidal volume?
Volume of air in each breath
What is ventilation rate?
Number of breaths per minute
What is Forced expiritary volume
Maximum volume of air that can be breathed out in one second
What is forced vital capacity?
Maximum volume of air that is possible to be breathed out of the lungs after a really deep breath in
