16. Intro to Respiratory System Flashcards Preview

Year 1 - Term 2: Carriage of Oxygen > 16. Intro to Respiratory System > Flashcards

Flashcards in 16. Intro to Respiratory System Deck (13):

What are the functions of the respiratory system?

What are the contents of the upper and lower respiratory tract?

Gaseous exchange, acid-base equilibrium, phonation, warming/humidification/filtration of gas (concha bones make air spin), defence (airbourne pathogens)

URT: oropharynx and larynx (non-respiratory)

LRT: 1) conducting airways (trachea and bronchi, non-respiratory) 2) gas exchange tissue (alveoli and terminal bronchioles, respiratory)


How many times does the airway tree divide?

Which are the conducting airways, and the respiratory zone?

Roughly how many alveolar ducts are there per lung, and what do they divide to?

Where does gas exchange occur?

How many albeoli in the lungs?


CA: first 16, RZ: last 7

8 million, divide to terminal alveolar sacs

Alveolar sacs, ducts and bronchioles

1 billion


What happens to the inward velocity of gas during inspiration as you go down the respiratory tree?

What is the volume of the conducting airways?

Define 'dead space gas'.

What type of epithelial cell is present in the conducting airways?

Becomes very small.


Exhale - have to breathe out volume of conducting airways first before you exhale alveolar gas - this gas = DSG.

Ciliated pseudostratified columnar epithelium


Label A-D in a conducting airway.

Q image thumb

A: columnar cells

B: cilia

C: goblet cell

D: mucus


NB. in lower condicting airways (bronchioles), simple epithelium only. Epithelium EXCEPT ALVEOLAR is covered with mucus


Describe the 2 types of epithelial cells.

What types of mobile cells are also present in high proportions in the alveoli?

Type 1 pneumatocytes: 90%, simple squamous

Type 2 pneumatocytes: 10%, cuboidal cells, secrete surfactant


Macrophages ("dust cells")


Label A-C in the lungs

Q image thumb

A: ciliated cell

B: goblet cell

C: connective tissue


What is surfactant?

Alveoli lined with water and dissolved surfactant = decreases surface tension and stops alveoli collapsing during exhalation (air pressure decreases)


Label A-C in the alveoli

Q image thumb

A: Type 1 pneumatocyte

B: Type 2 pneumatocyte

C: Alveolar macrophage (b/c mucus would compromise gas exchange, so no mucus but macrophages instead)


What is the formular for partial pressure of gas A?

What is the pO2 in dry inspired air?

To calculate pO2 of alveolar gas, what do you need to allow for and why?

What are the rough values of pO2 and pCO2 in the alveoli?

pA = total pressure in gas mixture x fractional concentration of A

Total pressure is atm (760mmHg) and fractional conc is 21%, so pO2 = 760 x 0.21 = 160mmHg

Account for H2O vapour in inspiration (44mmHg) b/c it decreases partial pressures of other gases, making pO2 = 155mmHg

pO2: 100mmHg pCO2: 40mmHg


What are rough values for A and B?

Q image thumb

A: pO2: 40 pCO2: 46

B: pO2: 95 pCO2: 40


What happens to pO2 at altitude and why?

Decreases because:

respiratory rate/depth increases; O2 fraction stays the same but total pressure decreases


What are the 3 most common respiratory diseases?

List some others.

List some infectious respiratory diseases.

Bronchitis, emphysema, pneumonia (fluid build up in alveoli so O2 diffusion compromised)

Asthma, COPD (chronic bronchitis + emphysema), tumors, pulmonary fibrosis, occupational lung disease, disorders of chest wall, pleura and diaphragm e.g. pneumothorax etc.

Common cold (acute coryza), influenza, pneumonia, pulmonary TB



What percentage of all acute illnesses are acute viral respiratory illnesses?

What percentage of GP consultations are respiratory?

What 3 factors are interlinked and affect respiratory disease?

1/2 or more e.g. adenovirus, rhinovirus


social (housing, smoking, travel, drugs), environmental (pollution, dust mites), occupational (allergies, chemical exposure)

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