Respiratory Physiology Flashcards
What are the functions of the respiratory system?
1.) gas exchange - oxygen/carbon dioxide
2.) acid base balance - regulation of body pH
3.) protection from infection
4.) communication via speech
Why is gas exchange so important?
Need to produce energy
How does it produce energy?
Do this by “burning” oxygen, produce carbon dioxide as a waste product
What does the ability of tissues to transform fuel stored as chemical energy to physical energy depend on?
The integration of the CVS and respiratory systems to deliver fuel to the active cells within the tissues, and remove waste products
What is cellular/internal respiration?
Biochemical process that releases energy from glucose either via Glycolysis or Oxidative Phosphorylation
What does oxidative phosphorylation depend on and require?
Depends on external respiration and requires oxygen
What is external respiration?
Movement of gases between the air and the body’s cells, via both the respiratory and cardiovascular systems
What is Exchange I?
Between atmosphere and lung
What is Exchange II?
Between lung and blood
What is Exchange III?
Between blood and cells
What is special about the pulmonary circulation?
It is opposite to the systemic circulation in function and terminology
What does the pulmonary circulation do?
It delivers CO2 (to the lungs) and collects O2 (from the lungs) while the systemic circulation delivers O2 to peripheral tissues and collects CO2
What does the pulmonary artery/pulmonary vein carry?
Pulmonary artery - deoxygenated blood
Pulmonary vein - oxygenated blood
What is the net volume of gas exchanged in the lungs/tissues per unit time?
250ml/min O2
200ml/min CO2
What is the normal respiration rate?
12-18 breaths/min at rest
Can reach 40-45 at max (exercising capacity in adults)
What are the main features of the respiratory system?
- nose
- pharynx
- epiglottis
- larynx
- trachea
- bronchus
- lung
What does the nose do in the respiratory system?
Air enters your body through your nose, where cilia and mucus trap particles and warm and moisten the air
What does the pharynx do in the respiratory system?
From your nose air moves down into the pharynx, or throat, which is shared with the digestive system
What does the epiglottis do in the respiratory system?
This small flap of tissue folds over the trachea and prevents food from entering it when you swallow
What does the larynx do in the respiratory system?
The larynx, or voice box, contains your vocal chords, which vibrate to produce sound
What does the trachea do in the respiratory system?
From the pharynx air moves down toward the lungs through your trachea, the trachea is made up of stiff rings of cartilage that support and protect it
What do the bronchus do in the respiratory system?
Air moves from the trachea into the right and left bronchi, which lead inside the lungs
What do the lungs do in the respiratory system?
The main organs of respiration, their soft, spongy texture is due to the many thousands of tiny hollow sacs that compose them
What does the upper respiratory tract contain?
- pharynx
- nasal cavity
- vocal chords
- esophagus
- tongue
- larynx
What does the lower respiratory tract contain?
- trachea
- right/left lung
- right/left bronchus
- diaphragm
What are the different lobes separated by on each lung?
Right lung
superior lobe -> horizontal fissure -> middle lobe -> oblique fissure -> inferior lobe
Left lung
superior lobe -> oblique fissure -> inferior lobe
How many times does each bronchus branch?
24 times (primary, secondary, tertiary, bronchioles)
What does patency mean?
The condition of being open or unobstructed
How is the patency of airway maintained?
C-shaped rings of cartilage
How is patency maintained in bronchioles?
No cartilage, maintained by physical forces in thorax
What is the alveoli?
Point of gas exchange
What are the alveoli covered in?
Elastic fibres
What do elastic fibres do?
Allow inflation of the alveoli during inspiration, and the energy that is stored in the elastic fibres as they expand is released during expiration to force air out of the alveoli
What do type I cells do?
Gas exchange
What do type II cells do?
Synthesize surfactant
What is the air in the airways called that doesn’t participate in gas exchange?
Anatomical dead space
What is the average total volume of the lungs?
6 litres
What is the normal volume for respiration?
2.3 litres —> 2.8 litres
What is tidal volume?
The volume of air breathed in and out of the lungs at each breath
What is the functional residual capacity?
Expiratory reserve volume + Residual volume
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 (roughly 3 litres)
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 (roughly 1-1.1 litres)
What is the dead space volume?
Roughly 150ml
What is residual volume?
The volume of gas in the lungs at the end of a maximal expiration
What is the vital capacity?
Tidal volume + Inspiratory reserve volume + Expiratory reserve volume
What is the total lung capacity?
Vital capacity + residual volume
What is the inspiratory capacity?
Tidal volume + Inspiratory reserve volume
How many pleural cavities is there?
2 (right and left)
What are the two types of membrane?
Parietal pleura and Visceral pleura
Where is the visceral pleural membrane found?
Adjacent to the lungs superior surface (visceral = generic term for organ)
Where is the parietal pleural membrane found?
Exterior surface of the pleural sac
What is a pneumothorax?
The seal between the membranes and chest wall is broken, so the chest wall continues to expand and the lung collapses to its unstretched size due to air entering the pleural cavity
What does Boyle’s Law state?
The pressure entered by a gas is inversely proportional to its volume
What does Dalton’s Law state?
The total pressure of a gas mixture is the sum of the pressures of the individual gases
What does Charles Law state?
The volume occupied by a gas is directly related to the absolute temperature
What does Henry’s Law state?
The amount of gas dissolved in a liquid is determined by the pressure of the gas and its solubility in the liquid
What muscles does inspiration use?
External intercostal muscles and the diaphragm, under heavy respiratory load the stemocleidomastoid and scalene muscles are used
What muscles does expiration use?
Passive at rest, but uses internal intercostal and abdominal muscles during severe respiratory load
What does the diaphragm do during inspiration?
Contracts to allow thoracic volume to increase
What do the external intercostal muscles do? and what do the internal intercostal muscles do?
Raise the rib cage upwards and outwards, and the internal intercostals do the opposite
What is intra-thoracic (alveolar) pressure?
Pressure inside the thoracic cavity, essentially pressure inside the lungs, may be negative or positive compared to atmospheric pressure
What is intra-pleural pressure?
Pressure inside the pleural cavity, typically negative compared to atmospheric pressure (in healthy lungs at least!)