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Flashcards in Module 4 Deck (59):
1

what are the 3 processes that make up respiration

1. ventilation of the lungs

2. exchange of rase between air and blood, and between blood and interstitial fluid

3. the use of oxygen in cellular metabolism

2

what is the primary function of the respiratory system

supply the body with oxygen and dispose of carbon dioxide

3

how is the respiratory structures divided structurally

1. upper respiratory system - filter, humidify and warm incoming air, reabsorb heat and water from outgoing heat

2. lower respiratory system - conducts air to the gas exchanges

4

how is the respiratory structures divided functionally

1. Conducting zone - passageways that conduct the air, cleanse, humidifying warm incoming air and reabsorb heat and water from outgoing air

2. The respiratory zone - respiratory bronchioles, alveolar ducts and alveoli, where gas exchange occurs

5

function of hairs in nose

filters course particles

6

role of mucosal epithelium

produces mucus

7

role of mucus

- humidifies incoming air

- traps particulates

8

role of mucociliary escalator

- removes contaminated mucus
- moves mucus
- protects the respiratory zone from damage and infection

9

role of nasal conchae

increases mucosal surface area and enhance air turbulence

10

describe inhalation

- network of blood vessels underlying the epithelium warm and moisten air.
- Generates turbulence which warms and moistens air

11

describe exhalation

reclaims heat and moisture

12

functions of nasal cavity

- filters/cleanses the air (hair + turbulence)

- warms and humidifies the air (capillary plexuses and mucus)

- traps particulates (mucus)

- kills bacteria (defensins)

- removes contaminated mucus (escalator)

- sneezing dislodging irritants

- olfaction

- resonating chamber of speech

13

role of the pharynx

- passageway for air and food

- facilitates voice production
- includes escalator

14

describe the structure of the trachea

- windpipe
- extends from larynx to bronchi
- includes escalator

15

describe the structure of the bronchi

- trachea divides to form the right and left primary bronchi

16

describe the structures of the bronchioles

- no escalator
- no cartilage rings
- abundant elastic fibres
- circular smooth muscle to alter diameter

17

what makes up the respiratory membrane

1. Alveolar epithelial cell (type 1)

2. Basement Membrane

3. Capillary enothelial cell

18

what is alveoli formed from

type 1 epithelial cells

19

what do type 2 epithelial cells secrete

surfactant which prevents alveolar collapse and antimicrobial proteins (e.g. defensins)

20

what is the site of gas exchange via simple diffusion

respiratory membrane

21

what are the 2 different types of circulations for the lungs

1. Pulmonary circulation

2. Bronchial Circulation

22

Pulmonary circulation

- pulmonary arteries deliver blood requiring oxygen

- pulmonary veins return oxygenated blood to the heart

- provides nutrients for alveoli

23

Bronchial Circulation

- bronchial arteries provide oxygenated systemic blood to the lung tissue

- pulmonary veins return most systemic blood back to the heart

24

list the ways in which the lungs are innervated (3)

1. Visceral sensory fibres
2. Parasympathetic fibres - constrict the bronchioles
3. Sympathetic fibres - dilate the bronchioles

25

describe the structure of the lungs and pleura
(outside to inside)

- thoracic wall
- parietal pleura
- pleural space
- visceral pleura

26

what does the parietal pleura cover

thoracic cavity wall

27

what does the visceral pleura cover

lungs

28

function of pleural fluid

facilitates adhesion of the visceral pleura covering the lungs to the parietal pleura lining the thoracic wall

29

inspiration

when air flows into the lungs

30

expiration

when air flows out of the lungs

31

what does pulmonary ventilation depend on

changes in the volume and pressure within the thoracic cavity and lungs

32

what type of gradient does air move

down a pressure gradient until equilibrium is reached

33

boyles law

decreased volume = increased pressure

34

mechanical events of inspiration

- thoracic cavity volume increases

- lungs stretch

- intrapulmonary volume increases

- air flows down the pressure gradient

- ribs elevates
- diaphragm moves up

- intercostal muscles contract

35

what are the inspiratory muscles

diaphragm and external intercostal muscles

36

mechanical events of expiration

- inspiratory muscles relax

- diaphragm descends

- rib cage descends

- thoracic cavity volume decreases

- intrapulmonary volume decreases

- intrapulmonary pressure rises

- air flows out of lungs down the pressure gradient to equal atmospheric pressure

37

describe passive expiration

- muscle relaxation
- depends on the elastic recoil of the lungs

38

describe forced expiration

- involves contraction of accessory muscles
- e.g. abdominal muscles

- increases intra abdominal and pushes diaphragm up

39

describe the 2 forces that act to collapse the lungs

- the lungs natural tendency to recoil
- surface tension of the alveolar fluid

40

what factors stop the lungs from collapsing

- surfactant: reduces surface tension of alveolar fluid

- adhesive forces of pleural fluid

- elasticity of the chest walls due to negative intrapleural pressure

41

what factors influence gas flow (ventilation) in the airways to the alveoli

- resistance
- compliance
- alveolar surface tension

42

describe resistance

- due to friction between the air and the airway walls
- dependant upon airway diameter

- altering bronchiole diameter regulates gas flow

43

sympathetic stimulation in context to resistance causes ..... ?

dilation = decreases resistance = increases gas flow

44

parasympathetic stimulation in context to resistance causes.... ?

constriction = increases resistance = decreases ventilation

45

describe pulmonary compliance

a measure of the ability of the lungs and/or thoracic cavity to expand/stretch and thus enable inhalation

46

what factors does compliance depend on

- lung elasticity
- alveolar surface tension (surfactant production)
- flexibility of muscles and joints of the thoracic wall

47

impact of alveolar surface tension

reduces alveoli to tallest possible size

makes alveolar expansion during inspiration difficult

48

describe infant respiratory distress syndrome

- premature infans
- do not produce adequate surfactant
- unable to keep alveoli inflated between breaths
- can result in alveolar rupture and haemorrhage

- treatment: spray airways with surfactant

49

how is pulmonary ventilation measured

- spirometre

50

tidal volume

amount of air inhaled or exhaled during quiet breathing

51

vital capacity

maximum amount of air that can be expired after maximal effort = total amount of exchangeable air in the lungs

52

describe obstructive pulmonary disorders

(cause, effect on VC, e.g.)

cause: reduced airway diameter and increased resistance and decreased air flow (dyspnea)

effect on VC: takes longer to achieve, more effort

e.g. emphysema

53

describe restrictive pulmonary disorders

(cause, effect on VC, examples)

cause: decreased compliance of lungs or thoracic wall = inability to change volume and thus draw in air

effect on VC: reduced

e.g. fibrosis

54

describe emphysema (obstructive)

alveolar destruction
bronchiole collapse during exhalation

55

describe bronchitis (obstructive)

inflammation and accumulation of mucus in lower airways

56

describe asthma (obstructive)

allergic inflammation leading bronchoconstriction

57

what can a decrease in compliance be a result of

- chronic inflammation and fibrosis
- lack of surfactant

58

what does the direction of gas movement depend on

the relative concentration of each gas in the alveoli compared with the blood

59

factors that influence the diffusion of O2 and Co2 across the respiratory membrane

1. Partial pressure

2. How soluble the gas is in the alveolar fluid and plasma

3. Matching of alveolar ventilation and pulmonary blood flow

4. Structural characteristics of the respiratory membrane