Respiratory System Flashcards
Where are the lungs housed?
in pleural sac in rib cage
What is the diaphragm?
The muscle responsible for inhalation and exhalation
Describe how inhalation occurs
Diaphragm contracts, expansion in the interpleural space and an increase in negative pressure occurs, therefore air enters the lungs
Describe how exhalation occurs
Diaphragm relaxes, decrease in interpleural space, positive pressure occurs and so air exits the lungs
What keeps the trachea open?
Cartilage rings on the outside which are for protection
Name the purposes of bronchi and cilia. When are cilia non functional?
1) Produce mucus via goblet cells to trap dirt particles and microorganisms
2) continuously cleared by cilia to pharynx and then swallowed
3) Cilia are non function in smokers
What does the bronchi branch to become?
Bronchioles (no cartilage rings) which branch to alveolar ducts which branch to alveoli
Number of alveoli and surface area?
about 500 million
70m(squared)
What do alveoli form?
Grape-like clusters called alveolar sacs
What are alveolar macrophages?
Phagocytic cells used for defence
How many alveolar macrophages are there?
12-14 in each alveoli
so 12-14 x 500million
What tends to accumulate in alveolar macrophages?
Basic drugs and macrolides
Continuous drug accumulation in AMs can cause
Phospholipidosis
When is the efficiency of bacterial phagocytosis in the lungs compromised?
In smokers and COPD patients
Diffusion is faster or slower in water?
Slower
Diffusion is directly proportional to?
surface area and membrane permeability
Diffusion also depends on..
the magnitude of the concentration gradient
What is carbonic anhydrase?
Fastest enzyme known. Important for CO2 elimination.
How is CO2 mostly transported?
By the blood in the form of HCO3-
happens via carbonic anhydrase
Name the first three steps of gas exchange (8 total)
1) Inhalation
2) Diffusion of 02 from alveoli to lung capillary
3) O2 diffuses to red blood cell and binds to haemoglobin
What happens in steps 4-8 of gas exchange?
After the red blood cell has O2 binded to its haemoglobin
4) O2 leaves haemoglobin and and diffuses into a tissue from a systemic capillary
5) CO2 diffuses from tissues to capillaries and is converted to HCO3- in erythrocytes
6) HCO3- travels in plasma and is then made to CO2
7) Diffusion of CO2 from capillary wall into alveoli
8) Exhalation
Describe the chosen treatment for respiratory disease such as ashtma and COPD
Dry powder inhalers
Metered dose inhalers- salbutamol and salmeterol
What does salmeterol do?
Treat the constriction of the airways
Name the two components of (brand name) Seretide
Salmeterol and Fluticasone
What is Fluticasone?
A corticosteroid
Advantages of pulmonary absorption?
Rapid due to large surface area of lungs (instantaneous absorption)
Avoids first pass metabolism
Local application at the site of action
Disadvantages of pulmonary absorption?
Commonly only 2-10% of dose is deposited in the lungs. 90% of the dose is swallowed.
