Week 4 - Why do we breathe?

Question 1

What are the functions of the respiratory system?

Answer 1

• respiration: ventilation (movement of air), external respiration (gas exchange from the lungs to the blood), transport of gases, internal respiration (gas exchange in the blood to the tissues)
• pH regulation
• voice production
• smell
• protection from dust and microorganisms

Question 2

What are the structural divisions of the respiratory system?

Answer 2

• lower resp tract: trachea, bronchi, lungs

- upper resp tract: nasal cavity, pharynx, larynx

Question 3

What are the functional divisions of the respiratory system?

Answer 3

• conducting zone: air through nose to bronchi

- respiratory zone: exchange of air in bronchioles, alveoli, alveoli ducts

Question 4

What is the external nose comprised of?

Answer 4

bone and cartilage (strat squamous)

Question 5

What is the nasal cavity comprised of?

Answer 5

• nostrils
• vestibule (entry to nasal cavity, stat squamous)
• hard palate (bone)
• septum (separates into left and right cavity)

Question 6

What is concha?

Answer 6

bony ridges, psedustratified ciliated columnar

Question 7

What is the role of concha?

Answer 7

creates airfow and turbulence to increase filtration of particles

Question 8

What are the functions of the nasal cavity?

Answer 8

• passageway for air
• cleans air
• humidifies and warms air (warm blood, moisture from mucus epithelium)
• olfaction
• sound of voice (resonating chamber)

Question 9

What are the three regions of the pharynx?

Answer 9

• nasopharynx: posterior to nasal cavity, pseudostratified ciliated columnar, opening for Eustachian tubes, pharyngeal tonsils
• oropharynx: posterior to oral cavity, stratified squamous, palantine and lingual tonsils
• lanryngeopharynx: posterior to epiglottis, stratified squamous

Question 10

What are the functions of the larynx?

Answer 10

• open passageway for air movement
• directs food into oesophagus
• sound production
• traps debris

Question 11

What are the cartilage rings in the larynx?

Answer 11

6 paired: arytenoid, corniculate, cuniform

3 unpaired: thyroid, cricoid, epiglottis

Question 12

Trachea

Answer 12

• anterior to oesophagus
• C shaped hyaline cartilage rings for support
• dense connective tissue, smooth muscles
• lumen = pesudotratified ciliated columnar + goblet cells

Question 13

What is seen as the trachea moves into the bronchioles?

Answer 13

increase smooth muscle and decrease cartilage

pseudostratified ciliated columnar –> simple ciliated columnar

Question 14

What is the order of air passage from the trachea to the bronchioles?

Answer 14

trachea –> primary bronchi –> secondary bronchi –> tertiary bronchi –> bronchioles –> respiratory bronchioles –> terminal bronchioles –> bronchioles

Question 15

Which type of epithelium cells are found in the alveoli?

Answer 15

simple squamous epithelium

Question 16

What are the two types of pneumocytes?

Answer 16

Type 1: gas exchange through simple diffusion

Type 2: cuboidal, secretes surfactant (prevents collapse, sticking)

Question 17

What is found on the capillary side of the membrane?

Answer 17

basement membrane, capillary epithelium (simple squamous), RBC

Question 18

What is the difference between the right and left lungs in regards to lobes, fissures, primary and secondary bronchi

Answer 18

RIGHT: 3 lobes, 2 fissures (horizonal and oblique), 1 primary bronchi, 3 secondary bronchi
LEFT: 2 lobes and cardiac notch, 1 fissure (oblique), 1 primary bronchi, 2 secondary bronchi

Question 19

What is the hilum?

Answer 19

entry point for blood, nerve supply and blood vessels

Question 20

What are the factors affecting gas exchange?

Answer 20

• thickness of respiratory membrane
• surface area
• diffusion coefficient
• partial pressure

Question 21

What are the percentages of oxygen that travels in the plasma and haemoglobin?

Answer 21

RBC (haemoglobin): 98.5%

Plasma: 1.5%

Question 22

What are the percentages of carbon dioxide that travel in the plasma?

Answer 22

HCO3-: 70%
dissolved in plasma: 7%
haemoglobin: 23%

Question 23

What occurs during inspiration in the lungs, diaphragm, rib cage, sternum, intercostal muscles?

Answer 23

Lungs: increase volume
Diaphragm: inferior, flattens
Rib cage: elevated
Sternum: elevated
Intercostal muscles: contact

Question 24

What occurs during expiration in the lungs, diaphragm, rib cage, sternum, intercostal muscles?

Answer 24

Lungs: decrease volume
Diaphragm: superior, relaxes (dome shape)
Rib cage: depresses
Sternum: depresses
Intercostal muscles: relaxes

Question 25

What is barometric air pressure?

Answer 25

atmospheric air pressure outside the body

Question 26

What is intra-alveoli pressure?

Answer 26

pressure inside alveoli

Question 27

How can alveolar pressure be changed?

Answer 27

• interpleural pressure
• forces which promote aleoli recoil (surfactant, elastic fibres)
• forces which promote lung expansion

Question 28

Tidal volume

Answer 28

amount of air inspired/expired with each breath

Question 29

Inspiratory reserve volume

Answer 29

amount of air inspired forcefully after expiration of a tidal volume

Question 30

Expiratory reserve colume

Answer 30

amount of air expired forcefully after inspiration of tidal volume

Question 31

Residual volume

Answer 31

volume of air still remaining in respiratory passages and lungs after most forceful expiration

Question 32

Pulmonary capacities

Answer 32

sum of two or more pulmonary volumes

Question 33

Inspiratory capacities

Answer 33

amount of air a person can inspire maximally after normal expiration (tidal volume + inspiratory reserve volume)

Question 34

Functional residual capacity

Answer 34

amount of air remaining in lungs at the end of normal expiration (expiratory reserve volume + residual volume)

Question 35

Vital capacity

Answer 35

max volume of air that can be expelled from the respiratory tract after max inspiration (inspiratory reserve volume + tidal volume + expiratory volume)

Question 36

Total lung capacity

Answer 36

inspiratory reserve volume + expiratory reserve volume + tidal volume + residual volume

Question 37

Minute respiration

Answer 37

total amount of air moved in and out of the system each minute

Question 38

Anatomic dead space

Answer 38

space formed by nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles; no gas exchange occurs here

Question 39

alveolar ventilation

Answer 39

volume of air available for gas exchange per minute

Question 40

What is the difference between static and dynamic lung function testing?

Answer 40

static: time is not a factor
dynamic: time is a factor

Question 41

What is an example of a dynamic lung function test?

Answer 41

forced vital capacity

Question 42

What is forced vital capacity? (FVC)

Answer 42

the max volume of air that can be forcefully expired as fast as possible after a deep breath in

Question 43

What is FEV1 sec?

Answer 43

volume of air expired in the first second

Question 44

What is FEV1%?

Answer 44

FEV1 sec/FVC x 100

Question 45

How do you read FEV1 sec and FEV1% on a vitalograph?

Answer 45

FVC = peak on graph

FEV1 sec= volume at 1 second

Question 46

What are the characteristics of a restrictive lung disease?

Answer 46

low FVC, low FEV1 sec, normal FEV1%, eg pulmonary fibrosis

Question 47

What are the characteristics of an obstructive lung disease?

Answer 47

normal FVC, FEV1 sec = low, FEV1% = low, eg asthma, emphysema