Respiration - Lecture 1 Flashcards
1
Q
What is the function of respiration?
A
gas exchange
2
Q
What happens during inspiration?
A
air rich in O2 is inhaled into the lungs
3
Q
What happens during expiration?
A
CO2 produced during oxidative processes of the body is exhaled from the lungs
4
Q
How is CO2 produced in the body?
A
during oxidative processes
5
Q
How are CO2 and O2 transported in the body?
A
by the blood
6
Q
What two systems are involved in respiration?
A
the cardiovascular and respiratory systems
7
Q
Which 2 surfaces does air pass through when it goes through the nose?
A
- nasal septum
- nasal turbinates
8
Q
What is the function of the nasal septum and the nasal turbinates?
A
they clean the air of big dust particles
9
Q
From the nose, warmed and moistened air flows through the common passages for air and food, the ____, and then continues through the _____.
A
pharynx, larynx
10
Q
Air reaches the periphery of the lungs via what 2 structures?
A
the trachea and bronchi
11
Q
What do airways consist of?
A
a series of tubes that branch and become narrower, shorter and more numerous as they penetrate into the lungs
12
Q
How many bronchi does the trachea divide into?
A
2
13
Q
What do the 2 bronchi divide into?
A
- lobular bronchi
- segmental bronchi
14
Q
How many lobar bronchi does the right main bronchus divide into?
A
3
15
Q
How many lobes does the right lung have?
A
3
16
Q
How many lobar bronchi does the left main bronchus divide into?
A
2
17
Q
How many lobes does the left lung have?
A
2
18
Q
What are the smallest airways without alveoli called?
A
terminal bronchioles
19
Q
What is the pleura?
A
a thin cellular sheet
20
Q
Where does the parietal pleura attach?
A
the thoracic cage interior
21
Q
Where does the visceral pleura attach?
A
the lung surface
22
Q
What does the visceral pleura form?
A
two enclosed pleural sacs (one around each lung)
23
Q
What is the pressure of the pleural space?
A
negative
24
Q
What is the function of the pleural space?
A
it creates a coupling between the ribcage and the lungs
25
What is the airway divided into?
the conducting zone and the respiratory zone
26
What do the conductive airways consist of?
the airways from the mouth and nose openings all the way down to the terminal bronchioles
27
What is the function of conductive airways?
they conduct air from the atmosphere to the respiratory part of the lungs
28
Do conductive airways contribute to gas exchange?
no, they compose anatomical dead space
29
When does the respiratory part of the lungs begin?
when the terminal bronchioles divide into respiratory bronchioles
30
What does the respiratory zone consist of?
the alveolar region
31
Where is the site of gas exchange?
the alveolar region of the lungs
32
Which zone makes up most of the lungs?
the respiratory zone
33
What are the smallest physiological units of the lungs (distal to the terminal bronchioles) called?
acinus
34
What are the 4 main functions of the conducting zone?
1. defence against bacterial infection + foreign particles
2. warms and moistens inhaled air
3. sound and speech
4. regulation of air flow
35
What do the epithelial linings of the bronchi have?
cilia
36
What does the epithelial glands of the bronchi secrete?
mucus
37
What is the function of cilia in the bronchi?
they sweep up the mucous into the pharynx
38
What is the mucociliary defence system?
when foreign particles stick to mucous and cilia sweep the mucous up into the pharynx
39
What is the function of the respiratory zone?
gas exchange between the air in the alveoli and the blood in the pulmonary capillaries
40
What 2 circulations do lungs have?
pulmonary and bronchial circulation
41
What is the function of the pulmonary circulation?
it brings mixed venous blood to the lungs so that it can get oxygenated and then back to the left heart
42
What is the function of the bronchial circulation?
it supplies oxygenated blood from the systemic circulation to the tracheobronchial tree (so that the airways get oxygenated)
43
Blood to the pulmonary capillaries is supplied via the ______
pulmonary artery (originates from the right ventricle)
44
What happens when the pulmonary artery reaches the alveoli?
the arterioles divide into a capillary bed
45
What do the pulmonary arteries supply blood to?
all capillaries within the alveolar walls
46
How does oxygenated blood from the alveolar capillaries return to the left heart?
via the pulmonary veins
47
What do the bronchial arteries from the aorta supply?
the airway walls
48
The bronchial circulation is part of which circulation?
the systemic circulation
49
What are the 3 alveolar cell types?
1. epithelial type I and II cells
2. endothelial cells
3. alveolar macrophages
50
What seals the alveolar epithelial cells?
tight junctions
51
What do type II epithelial cells produce?
pulmonary surfactant
52
What is surfactant?
a substance that decreases the surface tension of the alveoli
53
What do endothelial cells constitute?
the walls of the pulmonary capillaries
54
What is the function of the alveolar macrophages?
they remove foreign particles that may have escaped the mucociliary defence system of the airways
55
Why does surface tension happen in the lining of the lungs?
because the molecules at the surface of the film tend to arrange themselves in the configuration involving the lowest energy
56
How do the molecules at the surface of the film arrange themselves?
they "hold hands" rather than freely associate with air molecules
57
What happens if a film surface is curved in the lungs?
the tension can produce a pressure
58
What is LaPlace's Law?
P=4T/R
59
What does LaPlace's Law show?
that the pressure inside a small alveoli is greater than that inside a large alveoli
60
What does the soap bubble analogy suggest?
that small alveoli are likely to collapse into large ones (gas exchanging regions of the lung are unstable)
61
How is alveolar collapse prevented?
by pulmonary surfactant
62
What are the 2 principle roles of pulmonary surfactant?
1. it makes the surface tension inside the alveoli change with the lung volume (prevents the pressure inside the small alveoli from exceeding at of the large alveoli)
2. reduces overall surface tension so that we are able to breathe
63
What would happen if the surface tension in the liquid lining layer was equal to that of water?
we wouldn't be able to inflate our lungs
64
What are the 2 kinds of respiratory muscles?
inspiratory and expiratory
65
What is the main inspiratory muscle and what it is innervated by?
the diaphragm, innervated by the phrenic nerves C3, C4, C5
66
What happens when the diaphragm contracts?
its dome descends and the chest expands longitudinally
67
What raises the ribs during inspiration?
the contraction of the diaphragm and the external intercostal muscles
68
Why does the contraction of the diaphragm also elevate the lower ribs?
because of the vertically oriented attachments of the diaphragm to the costal margins
69
What happens as the ribs are elevated?
the anterior-posterior and transverse dimensions of the chest enlarge
70
In addition to the diaphragm, what other 4 muscles assist in inspiration?
1. the external intercostal muscles
2. the parasternal intercartilaginous muscles
3. the sternocleidomastoid
4. the scalenus muscles
71
Contraction of the inspiratory muscles is apparent during which disorder that obstructs the movement of air into the lungs?
asthma
72
What is the function of the neck muscles in inspiration?
they elevate and fix the uppermost part of the rib cage, elevate the sternum, and enlarge the anterior-posterior and longitudinal dimensions of the chest
73
Why is expiration passive during quiet breathing?
because of the recoil of the lungs and the chest wall
74
When do excitatory muscles become active?
during exercise and pathological states when expiratory resistance increases and the movement of airflow out of the lungs is impeded
75
Which muscles are involved during expiration?
internal intercostal muscles and the abdominal muscles
76
What happens when the abdominal muscles contract?
- the abdominal content is compressed
- the ribs are depressed
- the anterior part of the lower chest is pulled down
77
What happens to the diaphragm when the abdominal muscles contract?
it becomes forced upwards
78
What are the abdominal muscles essential for?
coughing, singing, talking, vomitting
79
What happens when there is forced maximal contraction of the expiratory muscles against a closed glottis (Valsalva's maneuver)?
there can be an increase in pressure (up to 100 mmHg)
80
What would happen if there is a sustained increase in pressure due to Valsalva's maneuver?
there would be a decrease in venous return to the heart , thus a decrease in cardiac output
