Respiratory System Flashcards
What happens during inspiration in breathing?
Diaphragm contracts - moves down
Increased volume in the thoracic cavity —> pressure decreases
Intrapulmonary pressure is lower than the atmospheric pressure resulting in air moving into the lungs
What happens during expiration in breathing?
Diaphragm relaxes and moves up
Decreased volume of thoracic cavity –> increased pressure
Intrapulmonary pressure is greater than the atmospheric pressure, air moves out of lungs
What units are intrapulmonary/intrapleural pressures etc measured in?
CmH2O
When is there a 0cmH2O intrapulmonary pressure?
At the end of exhalation when atmospheric pressure = intrapulmonary pressure
How does the intrapleural pressure change? What is the intrapleural pressure compared to the intrapulmonary pressure?
It fluctuates with breathing
Is 4cmH2O less than intrapulmonary pressure (-4cmH2O)
What is the purpose of the pressure difference between the intrapleural and intrapulmonary spaces?
The pressure difference across the alveolar wall keeps the stretched lungs adherent to the the chest wall
What is a pneumothorax? What happens as a result?
Air in the pleural space
Pressure difference between intrapleural and intrapulmonary space disappears
Lung recoils and collapses
What is the difference between an open and closed pneumothorax?
Open = opening in the chest wall - atmospheric air enters pleural space
Closed = chest wall is intact, rupturing of the lung/visceral pleura —> air into pleural space
What is used to treat a pneumothorax? How does it work?
Chest drainage system
Prevents air retuning to pleural space, straw attached to a chest tube and placed under fluid
Air moves out of lungs and cant be drawn back up the straw
What is the role of surfactant during inspiration?
When alveoli expand —> surfactant molecules move further apart
What is the role of surfactant during expiration?
Surfactant molecules move together —> surface tension reduced
What can surfactant deficiency result in?
Stiff lungs and difficulty breathing
Why are the inferior aspects of the lungs curved upwards?
Sits on top of the domed diaphragm
Why is the right lung often seen higher on x rays?
Due to the liver
What is the lobe structure of the right and left lung?
Right = 3 lobes Left = 2 lobes
What happens in the conducting portions of the respiratory system?
Air is moved from one place to the next (no gas exchange)
What happens at the respiratory portions of the respiratory system?
Gas exchange
Where does the respiratory system contain mucous membranes?
Lining the conducting portion of the respiratory tract
Where are serous membranes found in the respiratory system?
Lining the pleural sac of each lung
What is the outer and inner layer of each pleural sac called? What lies between the two layers?
Outer = parietal serosa
Inner = visceral serosa
Lubricating fluid
What is a pleural effusion?
When there is a watery transudate present in the pleural space
How is fluid drained from the pleural cavity?
Using a wide bore needle through the 7th intercostal space under ultrasound guidance
Why is it important to avoid; a) the inferior border of each rib and b) anywhere below the 7th intercostal space when draining fluid from the pleural space?
Blood vessels and nerves pass by the inferior border of each rib
Any lower than the 7th, may penetrate the diaphragm
What does impingement of the right or left phrenic nerve result in?
Paralysis of the diaphragm
What does impingement of the brachial plexus result in?
Wasting of the muscles in the lower arm
What does impingement of the sympathetic trunk result in?
Droopy upper eyelid
What does impingement on the left recurrent laryngeal nerve result in?
Hoarse voice
What structures form the conducting portion of the respiratory tract?
Nasal cavity Pharynx Larynx Trachea Primary bronchi Secondary bronchi Bronchioles Terminal bronchioles
What structures form the respiratory portion of the respiratory tract?
Respiratory bronchioles
Alveolar ducts
Alveoli
Which structure of the respiratory system are found inside/outside the lungs?
Outside = nasal cavity to primary bronchi
Inside = secondary bronchi to alveoli
What epithelium is found from the nasal cavity all the way through to the bronchioles?
Pseudostratified ciliated epithelium with goblet cells
Where is pseudostratified ciliated epithelium with goblet cells found in the respiratory system?
From the nasal cavity —> bronchioles
Which type of epithelium is found in the terminal bronchioles?
Simple columnar ciliated epithelium with clara cells
What epithelium is found in the respiratory bronchioles and alveolar ducts?
Simple cuboidal epithelium with less cilia and with clara cells
Which epithelium is found in the alveoli?
Simple squamous epithelium
What are the 2 regions of the nasal cavity?
Olfactory regions
Non-olfactory regions
Give a difference between the olfactory and non-olfactory regions?
Olfactory region contains olfactory cells and no goblet cells
Non-olfactory region contains mucous glands
What does the larynx consist of?
False vocal cord
Ventricles
True vocal cord
What is the purpose of the true vocal cord of the larynx?
Prevents foreign objects from reaching the lungs - lined with stratified squamous epithelium
What protects the lumen of the trachea?
C-shaped hyaline cartilage ring
What is the position of the oesophagus compared to the trachea? What muscle is associated with the trachea?
Oesophagus behind the trachea
Trachealis muscle
What does the trachea divide into? Where in the body?
2 primary bronchi in the mid-thorax
What are differences in histology between the trachea and primary bronchi?
Same histology - however the primary bronchi have complete hyaline cartilage rings and complete smooth muscle rings
Which primary bronchus is more prone to lodging of foreign objects and why?
Right bronchus
More vertical path
What is the structure of the wall of the trachea (and largely the primary bronchi)?
Pseudostratified ciliated epithelium —> lamina propria —> submucosa with mucous glands —> c shaped cartilage
What happens in COPD with regards to cilia and mucus?
There is hypertrophy of mucousal glands and hyperplasia of goblet cells —> more mucus
And less cilia to move it
What is the difference in structure between primary bronchi and secondary (and tertiary) bronchi?
Cartilage arranged as crescent shaped islands rather than full rings
What is the typical size of a bronchiole?
1mm or less in diameter
What is the structure of a bronchiole?
Has no cartilage or glands
What keeps bronchioles open?
Alveoli due to their elasticity
Which blood vessels supply the lungs with oxygenated blood?
Bronchial arteries
What happens to bronchioles during asthma? How does this affect breathing?
Bronchoconstriction - walls no longer held open by alveoli
More difficulty during expiration
When do goblet cells give way to clara cells in the respiratory tract?
From terminal bronchioles onwards
What two things do clara cells produce?
Secretes a surfactant lipoprotein - prevents walls sticking together
Secretes clara cell protein (CC16) marker for lung damage
What is the diameter of terminal bronchioles?
Less than 0.5mm
Which parts of the respiratory tract open on to alveoli?
Respiratory bronchioles
Alveolar duct
Alveolar sac
What is an alveolar sac?
Air space into which many alveoli open
Alveolar walls are supported by a basketwork of…
Elastic and reticular fibres
What two types of cells are found in the alveolar walls? In what percentages are they found?
Type 1 pneumocytes (90%)
Type 2 pneumocytes (10%)
What is the function of type 1 pneumocytes?
For gas exchange
What is the function of type 2 pneumocytes?
Production and release of surfactant
What other types of cells are found lining the alveolar surface (excluding type 1/2 pneumocytes)?
Macrophages
What is a hallmark sign of emphysema?
Pursed lip breathing
What causes emphysema?
Destruction of alveolar walls —> bronchioles collapse —> difficult for lungs to empty
What is pneumonia?
Inflammation of the lung caused by bacteria
Lung consolidates as the alveoli fill with inflammatory cells
