PHYSIOLOGY: Respiratory Physiology Flashcards
(105 cards)
1
Q
The combination of 3 processes is required for respiration to occur
A
- Ventilation (breathing)
- External (pulmonary) respiration
- Internal (tissue) respiration
2
Q
How many times does a normal human breath at rest?
A
12-15 Times a minute
3
Q
How much volume of air is there per breath?
A
500 mls of air
4
Q
Volume of air per minute a normal human breaths at rest
A
6-8 Litres per minutes are inspired and expired
5
Q
Gas exchange in the alveoli
A
Oxygen enters by simple diffusion in pulmonary capillaries
Carbon dioxide enters the alveoli
6
Q
Structurally, the components of the respiratory system are divided into 2 parts:
A
- Upper respiratory system
2. Lower respiratory system
7
Q
Nose, pharynx and associated structures are organs of what respiratory system?
A
Upper respiratory system
8
Q
Larynx, trachea, bronchi and lungs are organs of which respiratory system?
A
Lower respiratory system
9
Q
Functionally, the components of the respiratory system are divided into 2 zones:
A
- Conducting zone
2. Respiratory zone
10
Q
Structures of conducting zone
A
Nose
Mouth
Pharynx
11
Q
Functions of conducting zone
A
• Transports air to the lungs
• Warms, humidifies, filters, and cleans the
air
– Mucus traps small particles, and cilia move it away from the lungs.
• Voice production in the larynx as air
passes over the vocal folds
12
Q
• Transports air to the lungs
• Warms, humidifies, filters, and cleans the
air
– Mucus traps small particles, and cilia move it away from the lungs.
• Voice production in the larynx as air
passes over the vocal folds
A
Conducting zone
13
Q
The part of the airway that is not involved in gas exchange (conducting zone)
Is called.
A
Anatomical dead space
14
Q
Volume of anatomical dead space
A
Average 150 ml
15
Q
FORMULA of ALVEOLAR DEAD SPACE
A
Alveolar dead space=(Volume of fresh gas inhaled - anatomical dead zone ) X n of breaths
16
Q
The most important muscle of inspiration is?
A
Diaphragm
17
Q
At rest inspiration is?
A
Active
18
Q
At rest expiration is?
A
Passive
19
Q
During exercises expiration is ?
A
Active
Abdominal muscles contract
20
Q
Pressure changes that drive inhalation and exhalation are governed by
A
Boyle’s law
21
Q
The volume of a gas varies…….. with its pressure
A
INVERSELY
22
Q
As volume increases, pressure?
A
DECREASES
23
Q
As volume decreases, pressure?
A
INCREASES
24
Q
How much is Atmospheric pressure at rest?
A
760 mmHg
25
Alveolar pressure at rest
760 mmHg
26
Intrapleural pressure at rest
756 mmHg
27
At rest when the diaphragm is relaxed, alveolar pressure is equal to ?
Atmospheric pressure
28
Alveolar pressure during inhalation
758 mmHg
29
Intrapleural pressure during inhalation
753 mmHg
30
Atmospheric pressure during expiration
762 mmHg
31
Intrapleural pressure during expiration
756 mmHg
32
What is the pressure difference between intrapulmonary and intrapleural pressure called?
Transpulmonary pressure
33
Intrapulmonary pressure is the
Pressure in lungs
At rest= 760 mmHg - when no airflow
34
Factors affecting pulmonary ventilation
Elasticity
Lung compliance
Surface tension
35
Disorders that cause l’oss of elasticity is called?
Emphysema
36
The ease with which the lungs and thoracic wall can be expanded
Is called?
Lung compliance
Defined as the change in lung volume per change in transpulmonary pressure: ΔV/ΔP
37
Conditions with reduced lung compliance- make lung tissue stiffer?
Pulmonary fibrosis
38
Elastic tissue recoils during exhalation to aid?
The flow of air out of the lungs
39
The attraction between molecules at a gas/liquid interface that tends to pull those molecules together, can be defined as?
Surface tension
40
Effect of surface tension on alveolus
Increases the pressure within the alveolus
So smaller overkill have more tendency to collapse than larger ones
41
Smaller alveoli have more tendency to collapse than larger ones
True or false?
True
42
What reduces surface tension, and is essential to enable the expansion of alveoli
SURFACTANT
43
Normal breathing is defined as?
Eupnea
44
No breathing is defined as ?
Apnea
45
Laboured breathing is defines as ?
Dyspnea
46
Rapid breathing is defined as?
Tachypnea
47
Breathing by rib movement only is defined as?
Costal breathing
48
Breathing by diaphragmatic movement only is defined as?
Diaphragmatic breathing
49
Factors that affect gas exchange?
• • •
Surface area
Diffusion gradient
Diffusion distance (i.e. thickness of membrane)
FICKS LAW
50
Anything that affects diffusion will affect gas exchanges
True or false?
True
51
The total pressure of a gas mixture is equal to, according to Dalton’s Law?
Sum of pressure of each ga in it
52
Distance of diffusion
0.4-2.0 micrometeres
Very short
53
Distance of diffusion in increased if?
Fluid in lungs
- pneumonia
Mucus in lungs
- cystic fibrosis
54
At altitude, the reduction in PO2 is the
| stimulus for increased ventilation, whereas at sea level, it is ....... that is the. key influence
PCO2
55
Define partial pressure
The pressure of an individual gas; can be measured by multiplying the % of that gas by the total pressure (atmospheric)
Example:
O2 makes up 21% of the atmosphere, so : partial pressure of O2 = 760 X 21% = 159 mmHg
56
Oxygen diffuses from the alveoli into the pulmonary capillaries, carbon dioxide in the opposite direction
EXTERNAL RESPIRATION
57
Oxygen diffuses from the systemic capillaries into the tissues, and carbon dioxide in the opposite direction
INTERNAL RESPIRATION
58
The lung has two separate circulations?
Pulmonary circulation
Bronchial circulation
59
Pulmonary circulation
Brings deoxygenated blood from the right ventricle to the
| gas-exchanging units
60
Bronchial circulation
Arises from the aorta and nourishes the lung parenchyma.
61
The circulation to the lung is unique in?
- Dual circulation
- Ability to accommodate large volumes of
blood at low pressure.
62
Blood flow reaching alveoli is called?
Perfusion - Q
63
Amount of gas reaching alveoli is called ?
Ventilation - V
64
For efficient gas exchange what needs to be matched?
Perfusion and Ventilation
65
Due to gravity, lord flow is greater where?
At the base than at the apex of the lungs
66
Where in the lungs is the V/Q ratio higher?
At the apex
67
Average V/Q ratio (normal) in the whole lung
0.8 - Means more perfusion than ventilation
68
Lung perfusion can also be influenced by :
- cardiac output
| - Pulmonary vascular resistance
69
Ventilation increases in lungs from?
Tip to bottom
70
In the lung, at the Apices there is more........ than .....
More ventilation than perfusion= >0.8
71
In the lungs, at the base there is more ......... than ........
More perfusion that ventilation = <0.8
72
High V/Q ratio means
More VENTILATION that PERFUSION
> 0.8
73
Low V/Q ratio means?
There is more PERFUSION than VENTILATION
< 0.8
74
FEV and FCV in normal respiration ?
FEV = 4.0
FVC= 5.0
%= 80
75
FEV and FVC in obstructive respiration ?
FEV= 1.3
FVC= 3.1
%= 42
76
FEV and FVC in restrictive respiration?
FEV= 2.8
FVC= 3.1
%= 90
77
Factors that decrease V/Q ratio - Decreased ventilation (or increased perfusion)
* Chronic bronchitis (bronchospasm, inflammation, airway obstruction)
* Asthma (bronchoconstriction, excess mucus)
* Pulmonary oedema (fluid build up in the lungs)
* Pulmonary fibrosis (decreases compliance)
78
Factors that increase V-Q ratio - increased ventilation or decreased perfusion
- Pulmonary embolism
| - COPD
79
Bronchospasm, inflammation, airway obstruction)
Are symptoms of?
Chronic bronchitis
80
Bronchoconstriction, excess mucus
Are symptoms of?
Ashram
81
Fluid build up in lungs is associated to what disease?
Pulmonary oedema
82
Decreased compliance is associated to what disease?
Pulmonary fibrosis
83
Name the disease where a blood clot in the lungs may block lung blood vessels, resulting in limited perfusion to an area that is being ventilated effectively ; the overall V-Q ratio will therefore increase
Pulmonary embolism
84
Name the disease where patients have a high ventilation rate but poor perfusion due to damage to the alveoli; the level of ventilation is relatively high and V-Q ratio will increase
COPD
85
What is defined as a slight increase in PCO2 (and thus H+) and stimulates central chemoreceptors and peripheral (carotid) chemoreceptors
Hypercapnia
86
What is defined as oxygen cells deficiency at the tissue level, is caused by a low PO2 in arterial blood due to high altitude, airway obstruction or fluid in the lungs and stimulates peripheral (carotid) chemoreceptors
Hypoxia
87
The normal automatic process of breathing originates in
| impulses that come from?
The Brainstem
88
Which structure overrides the automatic process if breathing in the Brainstem when voluntary control is desired?
The cortex
89
Group of cells in the ventrolateral region known as the?
PRE-BOTZINGER COMPLEX
90
PRE-BOTZINGER COMPLEX is essential for?
Respiratory rhythm
91
Which cells have the property of INTRINSIC PERIODIC FIRING and are responsible for the basic Rhythm of ventilation?
A group of cells in the Dorsal Region- Dorsal respiratory group associated with inspiration and a Ventral respiratory group are associated with expiration
92
What receptors are:
- Located near ventral surface of medulla
- Sensitive to PCO2 but not PO2 of blood
- Respond to the change of pH of the ECF/CSF when CO2 diffuses out of the cerebral capillaries
Central chemoreceptors
93
What receptors:
- Located in the carotid and aortic bodies
- Respond to decreased arterial PO2 and increased PCO2 and H+ x - - - Rapidly responding
Peripheral chemoreceptors
94
What receptors:
- Pulmonary stretch receptors( slowly adapting) lie within airway smooth muscle.
- Discharge in response to distension in lung
- Activity sustained with lung inflation
Lung receptors
95
Impulses travel in which nerve?
Vagus nerve - via myelinated fibres
96
Which reflex:
- Provides self regulatory negative feedback mechanism - - Inflation inhibits further inspiratory muscle activity
- Deflation initiates inspiratory activity.
HERING-BREUER inflation reflex
97
Ventilation can be increased or reduced due to emotion; also transient effects such as gasping, sobbing etc
True or false?
True
98
Voluntary control of breathing is useful for ?
Communication
99
Name the disease:
- A chronic inflammatory condition of the airways x -Inflammation causes airways hyperresponsiveness
- Increased sensitivity to stimuli causes airway narrowing
- The response is reversible by bronchodilator drugs
Asthma
100
# Define the disease:
- Occurs when thrombi form in large veins and travel to the lungs, become lodged and occlude pulmonary circulation
- Often arise from deep veins of lower extremities but can originate from upper extremities, right side of heart and pelvic veins.
Pulmonary embolism
101
Venous thrombosis tend to form due to 3 important conditions :
* Virchow’s triad
* Stasis of blood
* Alterations in blood coagulation system
* Abnormalities of the vessel( intimal injury)
102
Diffusion gradient is increased by
Repeated replenishment of air with high PO2 and low PCO2
103
Diffusion gradient is decreased when?
Ventilation or blood flow are reduced e.g. lung blood flow reduced due to pulmonary embolism
104
Lungs can convert angiotensin I to Angiotensin II
True or false?
True
105
I’m the Fick’s law , rate of diffusion will double if?
- surface area or concentration difference is doubles
Or
- thickness of the exchange membrane is halved
