Basic concepts Flashcards

1
Q

What are the main features of the respiratory system for gas exchange?

A

Large SA, approx 50m squared

Bilipid membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Non-respiratory functions associated with the respiratory tract?

A

Producing Sound

Facilitating olfactory stimulation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Is engergy expended in breathing?

A

Yes. Apporximately 5% of normal energy output is used in providing respiratory function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Respiratory surfaces need protection from…?

A

Dehydration
Environmental variations
Pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does the upper respiratory tract consist of?

A

The URT consists of the:

  • Nasal cavity
  • Paranasal sinuses
  • Pharynx
  • Larynx
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the lining of the upper respiratory tract. What is its function?

A

Most of the lining in the URT is normal mucosa. It acts as protection and serves to warm and moisten air as it moves into the lower respiratory tract.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Name the 2 zones of the lower respiratory tract.

A
  • Conducting zone

- Respiratory zone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In total, how many generations are there in the respiratory tract.

A

23 generations.

*16 in the conducting zone and 7 in the respiratory zone.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Components of the conducting zone?

A

Trachea

First 16 generations.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Functions of the conducting zone?

A
  • Warms and humidifies inspired air
  • Distributes air evenly
  • Cleans air
  • Defense
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Components of the respiratory zone?

A

Last 7 airway generations and alveoli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Function of the respiratory zone?

A

The respiratory zone is the site of gas exchange.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How many lobar bronchi do we have?

A
  • 2 left lobar bronchi
  • 3 right lobar bronchi

This is in addition to the main bronchi, segmental bronchi and bronchioles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the histology of respiratory epithelium.

A

Respiratory epithelium is pseudostratified ciliated columnar epithelium with goblet cells.

Don’t forget the basement membrane is also there

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the histology of the lamina propria

A

Contains connective tissue, blood and lymph. There is also a band of fibroelastic tissue at the base of the lamina propria that becomes more prominent and muscular throughout the RT.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the histology of the submucosa

A

Smooth muscle and elastin fibres. Contains seromucus glands.

17
Q

What kind of cartilage is found in the respiratory tract?

A

Hyeline cartilage.

18
Q

Name the 2 types of cells found in the alveoli.

A
  • Type I pneumocytes- Squamous cells for diffusion of gases.

- Type II pneumocytes- Rounded cells which produce and secrete surfactant.

19
Q

How many alveoli do we have?

A

Approximately 500 million ‘bubbles’

20
Q

What are the main features of the alveoli?

A
  • Large SA, approximately 70m squared.
  • 1 cell thick
  • 0.2-0.5mm diameter.
  • Good blood supply
  • Rapid equilibration, approximately 0.25 seconds
  • Inherently unstable.
21
Q

Describe the changes in the partial pressures of oxygen during internal and external respiration.

A
  • Atmospheric air- PO2= 159 mmHg
  • Inhalation
  • Alveolar air- PO2= 105 mmHg
  • Passes into pulmonary capillaries and travels to left atrium.
  • Oxygenated blood- pO2= 100 mmHg
  • Travels to tissues via systemic capillaries
  • Systemic tissue cells- pO2= 40mmHg
  • Tavels from tissues to right atrium via systemic capillaries
  • Deoxygenated blood- pO2= 40mmHg
  • Travels back to lungs via pulmonary capillaries
  • Exhalation
22
Q

Describe the changes in the partial pressures of carbon dioxide during internal and external respiration.

A
  • Atmospheric air- pCO2= 0.3 mmHg
  • Inhalation
  • Alveolar air- pCO2= 40 mmHg
  • Passes into pulmonary capillaries and travels to left atrium.
  • Oxygenated blood- pCO2= 40mmHg
  • Travels to tissues via systemic capillaries
  • Systemic tissue cells- pCO2= 45 mmHg
  • Tavels from tissues to right atrium via systemic capillaries
  • Deoxygenated blood- pCO2= 45mmHg
  • Travels back to lungs via pulmonary capillaries
  • Exhalation
23
Q

What is the main factor affecting paO2?

A

paO2 is mainly affected by the state of the air-blood barrier and the respiratory system functionality.

24
Q

Which law describes the rate of gas diffusion into the blood?

A

Fick’s law.

*Learn the equations, they’ll come in handy during exams**

25
Q

How is oxygen transported in blood?

A

1) Physically dissolved (1.5%)
- Exerts a pressure (paO2)
- carrying capacity in plasma= 0.3ml O2/ 100ml blood
2) Bound to haemoglobin (98.5%)
- Each gm of haemoglobin carries 1.34ml O2.
- Typically there’s 15gm Hb per 100 ml of blood
- O2 carrying capacity= 19.7ml/100ml

26
Q

Total O2 content in blood?

A

Approx. 20ml O2/ 100ml blood

27
Q

Name the respiratory defense mechanisms in place in the upper airways.

A

i) Nasopharynx: -Nasal hair
- Turbinates
- Mucociliatory apparatus
- IgA secretion
ii) Oropharynx: - Saliva
- Sloughing of epithelial cells
- Local compliment production
- Interference from resident flora.

28
Q

Name the respiratory defense mechanisms in place in the conducting airways.

A

Trachea, bronchi: -Cough, epiglottic reflexes

                          - Sharp-angled branching of airways
                          - Mucociliary apparatus
                          - Ig secretion (A, G, M)
29
Q

Name the respiratory defense mechanisms in place in the lower airways.

A

Terminal airways, alveoli: - Alveolar lining fluid

                                       - Cytokines
                                       - Aveolar macrophages
                                       - Neutrophils
                                       - Cell-mediated immunity
30
Q

How are inhaled particles removed?

A
  • Large particles are filtered out in the nose.
  • Mucociliary elevator
  • Those that enter the distal respiratory tree are phagocytosed by alveolar macrophages
  • Some organisms may reach draining lymph nodes and initiate immune responses.
31
Q

What is the mucociliary elevator?

A

A major barrier against infection.

32
Q

Which mechanisms operate to remove inhaled particles after the development of adaptive immunity?

A

1) URT- Secreted IgA blocks attachment to epithelium
2) LRT- Serum antibodies are present in the alveolar lining fluid.
3) T-cell immunity