Block E Part 2: Lungs, Gas Exchange and Respiratory Diseases Flashcards
How are lungs divded?
Into several lobes (2 on the left, 3 on the right)
(Lecture 2, Slide 3)
What occupies most of the volume of the thoracic (chest) cavity?
The lungs
(Lecture 2, Slide 3)
What separates the thoracic (chest) and abdominal cavities?
The diaphragm
(Lecture 2, Slide 3)
What 2 cells make up the respiratory defence system?
Columnar epithelial cells and goblet cells
(Lecture 2, Slide 5)
What do columnar epithelial cells have on their surface?
Cilla (small, slender hair like structures)
(Lecture 2, Slide 5)
What do goblet cells secrete?
Mucous
(Lecture 2, Slide 5)
What are alveoli?
Tiny air sacs at the end of the bronchiole
(Lecture 2, Slide 7)
What are alveoli surrounded by?
Capillaries
(Lecture 2, Slide 7)
What are type 1 alveolus cells?
Small epithelial cells with no Cilla across
(Lecture 2, Slide 9)
Where does gas exchange occur?
Type I alveolar cells
(Lecture 2, Slide 9)
What do type II alveolar cells secrete and what does this do?
They secrete surfactant, a substance that facilitates lung expansion
(Lecture 2, Slide 10)
How do macrophages prevent infection in the alveoli?
By removing foreign material
(Lecture 2, Slide 11)
Which way does air move in the pressure gradient?
Down - i.e from a region of higher pressure to a region of lower pressure
(Lecture 2, Slide 13)
How does air flow in and out of the lungs?
Alternatively reversing pressure gradients
(Lecture 2, Slide 13)
What is Boyle’s law?
At any constant temperature, the pressure exerted by a gas varies with the volume of the gas
(Lecture 2, Slide 14)
What happens when intra-alveolar pressure < atmospheric pressure and why?
Air flows into the lungs as it has lower pressure
(Lecture 2, Slide 15)
What happens when intra-alveolar pressure > atmospheric pressure and why?
Air flows out of the lungs as pressure is lower outside the body
(Lecture 2, Slide 15)
What is the first step of ventilation?
The external intercostal muscles contract to increase chest volume
(Lecture 2, Slide 16)
What is the second step of ventilation?
The diaphragm lowers
(Lecture 2, Slide 16)
What is the third step of ventilation?
Air flows in as air pressure in the lungs is lower than that outside
(Lecture 2, Slide 16)
What is the fourth and final step of ventilation?
Air flows out when muscles relax
(Lecture 2, Slide 16)
What is asthma?
A chronic inflammatory disease of the airways of the lung
(Lecture 2, Slide 18)
Why does the smooth muscles around the bronchioles contract more in people with asthma?
As it is hyperexcitable
(Lecture 2, Slide 18)
What creates the characteristic wheezing sound of asthma?
Increased resistance to airflow in and out of the lung
(Lecture 2, Slide 18)
What, other than the increased air resistance, further inhibits air flow in and out of the lungs in people with asthma?
Increased mucus secretion
(Lecture 2, Slide 18)
What are 3 triggers for an asthma attack?
Exercise, cold temperature and allergens
(Lecture 2, Slide 19)
How does ß-adrenoceptor agonist treat asthma?
It relaxes the bronchiole smooth muscle
(Lecture 2, Slide 20)
How does corticosteroid treat asthma?
It reduces inflammation
(Lecture 2, Slide 20)
What is emphysema?
A long-term progressive disease of the lungs
(Lecture 2, Slide 22)
What 3 things does emphysema cause?
Shortness of breath, coughing and continuous wheezing
(Lecture 2, Slide 22)
What are destroyed / damaged in emphysema?
Alveoli and bronchioles
(Lecture 2, Slide 22)
What does bronchioles being destroyed due to emphysema lead to?
Airway collapse and difficulty in emptying gases from the alveoli
(Lecture 2, Slide 22)
What is a significant cause of emphysema?
Cigarette smoking
(Lecture 2, Slide 22)
What are 4 ways to treat emphysema?
Quit smoking
Bronchodilators
Corticosteroids
Oxygen therapy
(Lecture 2, Slide 23)
How do bronchodilators treat emphysema?
It opens up airways
(Lecture 2, Slide 23)
What is cystic fibrosis?
A thick, sticky mucus blocks the airway
(Lecture 2, Slide 24)
How do you get cystic fibrosis?
It’s an inherited condition
(Lecture 2, Slide 24)
What parts of the body does cystic fibrosis affect?
The lungs, digestive system and other organs
(Lecture 2, Slide 24)
Name 3 ways to treat cystic fibrosis.
Airway clearance (physiotherapy)
Antibiotics
Corticosteroid
Pancreatic enzyme replacement therapy
High calorie diet
(Lecture 2, Slide 25)
What is Dalton’s law?
In a mixture of non-reactive gases, the total pressure exerted is equal to the sum of the partial pressures of the individual gases
(Lecture 2, Slide 27)
How is the exchange of oxygen and carbon dioxide across the alveoli achieved?
By diffusion
(Lecture 2, Slide 28)
What does gas exchange in the alveoli depend on?
The differences in partial pressure across the respiratory membrane
(Lecture 2, Slide 28)
How big are the distances involved in the gas exchange?
Small
(Lecture 2, Slide 28)
Where does oxygen move during gas exchange in the alveoli?
From the lungs to the blood stream
(Lecture 2, Slide 29)
Where does carbon dioxide move during gas exchange in the alveoli?
From the blood stream to the lungs
(Lecture 2, Slide 29)
