Respiratory Physiology 1-5 Flashcards
What is the upper respiratory system composed of?
The mouth, nasal cavity, pharynx and larynx.
What is the lower respiratory system composed of?
Trachea, bronchi and lungs.
What are characteristics of the right lung?
Composed of three lobes and a wider, more vertically oriented bronchi.
What are characteristics of the left lung?
Composed of two lobes and a narrower bronchi.
Which bronchii is more prone to issues?
The right bronchi as it is more vertically oriented which increases the risk of foreign bodies becoming trapped.
What are the different classes of airways?
Bronchi- conducting airways with cartilage.
Bronchioles- conducting airways without cartilage.
Alveoli- non-conducting airways participating in gas exchange.
What are the two types of alveolar cells and their associated functions?
Type 1- responsible for gas exchange.
Type 2- synthesise surfactant.
List the functions of the respiratory system.
Gas exchange.
Maintaining acid-base balance (regulation of pH).
Protection from infection.
Communication via speech.
What is the difference between pulmonary and systemic circulation?
The pulmonary circulation delivers carbon dioxide to the lungs and collects.
The systemic circulation delivers oxygen to the peripheral tissues and collects carbon dioxide.
What does the pulmonary artery carry?
Deoxygenated blood away from the heart to the lungs.
What does the pulmonary vein carry?
Oxygenated blood from the lungs towards the heart.
Identify points of gas exchange between the respiratory and cardiovascular systems.
Gas exchange only occurs in the alveoli, which are in direct contact with capillaries of the CV system.
Understand why, and how, resistance to air flow varies across the respiratory tree.
As the airways narrow, the resistance to airflow becomes greater.
Resistance to air flow can be altered by activity of bronchial smooth muscle.
What is tidal volume? how many ml?
The volume of air breathed in and out of the lungs at each breath.
500ml
What is the expiratory reserve volume?
The maximum volume of air which can be expelled from the lungs at the end of a normal expiration.
What is the inspiratory reserve volume?
The maximum volume of air which can be drawn into the lungs at the end of a normal inspiration.
What is the residual volume?
The volume of gas in the lungs at the end of a maximal expiration.
Describe the anatomy of the pleural cavity?
The lungs and interior of the thorax are covered by pleural membranes between the surfaces which is an extremely thin layer of intrapleural fluid.
Describe the relationship between the visceral and parietal pleura.
The visceral pleura is stuck to the outer surface of the lungs.
The parietal pleura is stuck to the ribcage and diaphragm.
The visceral and parietal pleura are stuck together via the cohesive forces of the pleural fluid.
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What are the muscles involved with inspiration and what do they do?
External intercostal muscles.
The diaphragm.
Accessory muscles (e.g. sternocleidomastoid).
-Act to increase thoracic volume.
What are the muscles involved with expiration and what do they do?
Expiration is passive at rest but uses internal intercostal and abdominal muscles during severe respiratory load.
-Act to decrease thoracic volume.
What does Boyle’s Law state?
Boyle’s law states that the pressure exerted by a gas is inversely proportional to its volume.
Relate Boyle’s law to inspiration.
During inspiration, the increase in thoracic volume will cause a decrease in pressure within the lung, causing air at atmospheric pressure to rush into the lungs.
Relate Boyle’s law to expiration.
During expiration, a decrease in thoracic volume increases the pressure within the lungs. This causes air to rush out of the lungs.
What is alveolar pressure (PA)?
The alveolar pressure (PA) is the pressure inside the thoracic cavity, (essentially pressure inside the lungs). It may be negative or positive compared to the atmospheric pressure.
What is the intrapleural pressure (Pip)?
The intrapleural pressure (Pip) is the pressure inside the pleural cavity, typically negative compared to the atmospheric pressure (in healthy lungs).
What is the transpulmonary pressure (PT)?
The transpulmonary pressure (Pt) is the difference between the two. Almost always positive as Pip is negative (in health). Pt= Palv – Pip.
State the role of pulmonary surfactant.
The surfactant is a detergent-like fluid that reduces surface tension on the alveolar surface membrane thus reducing the tendency for alveoli to collapse. due to surface tension.
Does surfactant increase lung compliance (distensibility)?
Yes, it it reduces the lungs tendency to recoil and makes breathing easier.