Why do we breathe? - Compendium 4 Flashcards
Describe the basic anatomy of the respiratory tract beginning at the nasal cavity and ending at the alveoli.
Nasal Cavity Pharynx Larynx Trachea Primary Bronchus Secondary Bronchus Tertiary Bronchus Bronchiole Terminal Bronchiole Respiratory Bronchioles Alveolar Duct Alveolar Sac Alveoli
List the five components of the respiratory membrane
Alveolar fluid (with surfactant) Alveolar epithelium Basement membrane of alveolar epithelium Interstitial space Basement membrane of capillary
Explain the role of the thoracic wall and pleura in respiration
a. The thoracic wall protects the lungs and changes the thoracic volume during respiration. The pleura acts as a lubricant between the thoracic wall and the lungs, it also allows optimal expansion and contraction of the lungs during respiration.
Explain how contraction of respiratory muscles causes a change in thoracic volume during quiet and active breathing.
a. Quite breathing: the diaphragm contracts and pulls down the pleura causing the thoracic volume to increase and therefore lung pressure to decrease.
b. Active Breathing: The diaphragm and the muscles of the thoracic wall pull in the pleura and expand the thoracic cavity and therefore decrease lung pressure. The abdominal muscles are used for forceful expiration they contract and push the pleura to decrease thoracic volume and expel air out of the lungs.
Describe the changes in alveolar pressure and how they relate to the movement of air into and out of the lungs
Alveolar pressure is higher than barometric pressure the air in the lungs will be forced out. When it is lower the air will rush into the lungs. This happens because gases flow from high pressure to low pressure states to equalize.
Describe how surfactant and pleural pressure prevent lung collapse
Surfactant reduces surface tension in the alveoli and stops it from pulling in on itself and collapsing. The pleural pressure does the opposite and has a high tension to pull the lungs from the outside and prevent their collapse.
Describe the mechanism of gas exchange and gas transport around the lungs
The oxygen goes from the alveoli to the red blood cells via diffusion and then is pumped through the heart and gets distributed to the necessary tissues via diffusion. The oxygen is used and leaves CO2. The excess CO2 is taken from the tissues and back to the lungs to then be expelled through expiration.
Define Alveolar Ventilation
How much air per minute enters the parts of the respiratory system where gas exchange takes place
Define pulmonary volumes
The volume of specific measurements of the lung capacity
Tidal Volume
Inspiration Volume
Expiration volume
Residual Volume
Define Pulmonary Capacities
The sum of two or more pulmonary volumes
Why do we breathe air?
We breathe air in order to circulate oxygen through the blood and around the body. It is used in a process called cellular respiration. The oxygen is used to create energy in the form of Adenosine triphosphate.
How does the respiratory tract protect itself from dust and pathogens?
Most of the respiratory tract is lined with cilia which act to move dust particles and pathogens out of the lungs and for the parts without cilia there are alveolar macrophages which remove fine dust and debris from alveolar spaces
How are O2 and CO2 exchanged in the alveoli?
They are exchanged through a process called diffusion
Why does expanding your thoracic cavity make you breathe in?
It creates a pressure differential from the outside air and the inside of your lungs. The air on the outside has a higher pressure and therefore rushes into the lungs to even out the pressure difference
Why would your lungs collapse if you were stabbed in the chest?
The pleural cavity pressure would change and squeeze / collapse the lung
