lungs deck Flashcards
1
Q
Define respiration
A
the process by which oxygen is taken in and carbon dioxide is given out.
2
Q
The first breath takes place only after…
A
birth
3
Q
This is cus fetal lungs are…
A
non functional
4
Q
During intrauterine life the exchange of gases between fetal blood and mother’s blood occurs through…
A
placenta.
5
Q
What are the two types of respiration?
A
external and internal respiration
6
Q
What is external respiration?
A
involves exchange of respiratory gases, i.e. oxygen and carbon dioxide between lungs and blood
7
Q
What is internal respiration?
A
involves exchange of gases between blood and tissues
8
Q
Internal and external respiration take place at the same…
A
time
9
Q
Where does external respiration take place?
A
between environment and lungs
10
Q
Where does internal respiration take place?
A
between blood and cell.
11
Q
Describe the process of external respiration
A
1) Ventilation of gas exchange between the atmosphere and alveoli in the lungs
2) Exchange of O2 and CO2 between air in the alveoli and the blood in the pulmonary capillaries
3) Transport of O2 and CO2 by the blood between the lungs and the tissues
4) Exchange of O2 and CO2 between the blood in the systemic capillaries and the tissue cells.
12
Q
Why do we breathe?
A
1 Take in oxygen
2 remove carbon dioxide
13
Q
Other roles of the respiratory system?
A
- Allows speech
- Acid-base balance
- Water balance
- Maintain body temperature
14
Q
Respiration occurs in two phases which are …
A
inspiration and expiration
15
Q
What’s inspiration?
A
air enters the lungs from atmosphere
16
Q
What’s expiration?
A
air leaves the lungs
17
Q
The respiratory system is an …
A
arrangement of spaces and passageways that conduct air into the lungs.
18
Q
The entire respiratory system is thought of as a…
A
pathway for air between the atmosphere and the blood
19
Q
What is respiratory system divided into?
A
upper and lower respiratory system.
20
Q
What makes up the upper respiratory system?
A
nose
nasal cavity
sinuses
pharynx
21
Q
What makes up lower respiratory system?
A
larynx
trachea
bronchus
bronchioles
alveoli
22
Q
How does air first enter the body?
A
Air makes its initial entrance into the body through the openings in the nose called the nostrils.
23
Q
What is found inside the nostrils?
A
inside the nostrils, are the two spaces known as the nasal cavities.
24
Q
Nasal vestibule is lined with…
A
hairs
25
Function of hairs in the nose?
filter large particles from inhaled air.
26
What is nasal cavity divided into?
left and right chambers with folds.
27
What are conchae also known as?
turbinates.
28
Function of nasal conchae?
increased surface area.
29
The lining of the nasal cavity is a ...
mucous membrane
30
What does the nasal cavity contain?
many blood vessels that bring heat and moisture to it.
31
What do the cells of the nasal cavities membrane secrete?
a large amount of fluid.
32
What do the nasal cavities filter?
Foreign bodies, such as dust particles and pathogens, are filtered out by the hairs of the nostrils or caught in the surface mucus.
33
How does nasal cavity moisten air?
moistened by the liquid secretion.
34
What are sinuses?
Air-filled spaces within the bones of the skull that connect to the nasal cavity
35
What do sinuses produce?
mucus
36
Sinuses functions?
Produce mucus to clean the air you breathe
Reduce the relative weight of the skull
Act as resonating chambers to modify sounds
Provide a cushion against impact
37
What is the nasal cavity, sinuses, and conchae lined with?
all are lined with a mucous membrane.
38
Describe the nasal epithelium?
* highly vascularised
* Has ciliated epithelium
* Warm and humidify inhaled air
39
Where is nasal epithelium present?
Nasal cavity, sinuses & conchae
40
Nasal cavity, sinuses & conchae are lined with...
... a mucous membrane
41
Nasal mucous is the nose's...
first line of defense
42
What does mucous trap?
traps noxious substances (bacteria, viruses, pollen, dust.).
43
What does the pharynx do?
The pharynx (throat) carries air into the respiratory tract and foods and liquids into the digestive system.
44
The pharynx is divided into...
3 sections
45
What are the three sections of the pharynx?
1) Nasopharynx - located posterior to the nasal cavity
2) Oropharynx - posterior to the oral cavity
3) Laryngopharynx - located close to the vocal chords and trachea
46
Function of nasopharynx?
Receives air from the nasal cavity and conduct air to the lower sections of the respiratory tract
47
Function of oropharynx?
receives air from the nose and mouth (and food).
48
Function of laryngopharynx?
Continuous with the larynx and the oesophagus
Conducts air into the trachea.
49
What closes over the larynx during swallowing?
During swallowing, the epiglottis closes over the larynx to prevent food or liquids from entering the lungs.
50
The larynx has a framework of...
cartilage that protrudes in the front of the neck.
51
The largest cartilage of the larynx is the ...
thyroid cartilage.
52
Males have a more prominent...
thyroid cartilage (laryngeal prominence, adams apple).
53
What are the vocal chords?
two v shaped bands of muscle.
54
In vocal cords, air flow =
vibration
55
Vibration produces...
sound
56
When breathing, the vocal cords...
open, allowing air to move in and out.
57
When do vocal chords close?
They close when we talk and vibrate to allow us to produce sounds
58
The nasal cavity and sinus acts as a ...
resonating chamber to help form the sound
59
Why do males have deeper voices than females?
Testosterone in males produces thicker/longer folds that vibrate slower
- Producing the deeper voice
60
What is the larynx lined with...
ciliated mucous membrane
61
Function of cilia?
trap dust and other particles, moving them upward to the pharynx to be expelled by coughing, sneezing, or blowing the nose.
62
Mucous secreting cells in the body are referred to as?
goblet cells.
63
Function of ciliated cells?
sweep debris
64
Function of clara cells?
divide, differentiate, metabolize toxic chemicals.
65
What is the trachea (windpipe)?
a tube that extends from the lower edge of the larynx to the bronchi
66
Trachea has a framework of...
cartilages to keep it open
67
The purpose of the trachea is to...
conduct air between the larynx and the lungs.
68
What cells do trachea contain?
Numerous cilia cells & goblet cells
69
Trachea contains numerous cilia cells and goblet cells. What is the function of this?
- produce mucus
- mucus-cilia elevator/escalator
- pushes mucus up
70
What does the trachea divide into?
divide into left and right primary bronchi.
71
The trachea divides into...
two bronchi which enter the lungs.
72
The right bronchus is considerably larger in ...
diameter than the left and extends downward in a more vertical direction
73
The trachea divides into the bronchi, which is further divided into the ...
bronchioles
74
What is the wall of the thorax abundant with?
abundant connective tissue with elastic properties
75
The thorax is a ...
closed compartment.
76
The lungs are found in a ...
closed compartment.
77
Black sections on a scan are...
air
78
The white sections on a scan are...
the heart or diaphragm.
79
Function of the oblique and horizontal fissures?
allow lungs to slide over each other.
80
In the lungs are cluster of air sacs, resembling a...
bunch of grapes.
81
In the lungs are cluster of air sacs, resembling a bunch of grapes. These sacs are known as...
alveoli
82
These sacs are known as alveoli. This very thin wall provides easy passage for ...
the gases entering and leaving the blood.
83
The lungs lie in...
the pleural cavity
84
Two pleural cavities (pleurae) filled with...
intrapleural fluid
85
Each lung occupies a single...
pleura
86
Intrapleural fluid enables...
efficient lung ventilation.
87
Pleura consists of ...
2 layers
88
What are the two layers of pleura?
Parietal pleura
Visceral pleura
89
Function of parietal pleura...
covers inner surface of thoracic wall.
90
Function of visceral pleura...
covers outer surfaces of lungs.
91
What do both layers of pleura secrete?
Both secrete pleural fluid
92
In some pathological conditions, the pleural cavity ....
expands with accumulation of:
* air (pneumothorax),
* water (hydrothorax),
* blood (hemothorax) or
* pus (pyothorax)
93
What is surfactant...
a mixture of lipids, proteins, and carbohydrates that coats the air sacs (alveoli).
94
Where is surfactant produced?
produced by Type II Pneumocytes (or alveolar type II cells) in the alveoli.
95
Surfactant is not produced until?
late in foetal life (8 months)
96
What is the purpose of surfactant?
to reduce surface tension and prevent alveoli from collapsing
97
What does surfactant deficiency lead to?
Deficiency leads to respiratory distress syndrome in premature infants
98
Most Premature babies' lungs lack...
sufficient surfactant
99
As a result of deficient surfactant, alveoli collapses... Which is called...
Infant Respiratory Distress Syndrome (IRDS)
100
What is the diaphragm?
The diaphragm is a large, dome-shaped muscle that contracts and relaxes to move air into and out of the lungs
101
Pressure of a gas is inversely proportional to ...
its volume
102
Contraction and relaxation of the diaphragm ensures...
inspiration and expiration.
103
What is Boyle's law?
‘Pressure of a gas is inversely proportional to its volume
As volume increases... pressure decreases
As volume decreases... pressure increases.
104
An increase in volume of lungs decreases...
pressure of gas; allows air to move in.
105
Pressure changes result from ...
changes in thorax volume
106
Palv < Patm =
Air flows inward - INSPIRATION
107
Palv > Patm =
Air flows outward - EXPIRATION
108
Air flows from areas of ...
higher pressure to areas of lower pressure.
109
What are the two phases of ventilation?
Inhalation and Expiration.
110
What is inhalation?
the drawing of air into the lungs.
111
What is exhalation?
Exhalation is the expulsion of air from the lungs.
112
Describe process of inhalation?
1. During inhalation, the diaphragm contracts and is drawn downwards
2. The intercostal muscles between the ribs contract and raise ribcage up and outward
3. The chest cavity expands, and intra-alveolar (lung) pressure is reduced
4. The lungs are pulled outwards and expand, drawing air into them
113
Describe process of exhalation?
1. The diaphragm relaxes and moves upwards
2. The intercostal muscles relax and the ribcage moves inward and downward
3. The volume of the chest cavity is reduced and pressure increases
4. The lungs contract, forcing air out of them
114
What are pulmonary volumes and capacities?
These are the different amounts of air in the lungs during different phases of breathing
115
What is inspiratory reserve volume (IRV)?
the amount of air that you can breathe in over and above the tidal volume
116
What is the resting tidal volume (Vt)?
the amount of air you move into or out of your lungs during a single respiratory cycle under resting conditions
117
What is the expiratory reserve volume (ERV)?
the amount of air that you can voluntarily expel after you have completed a normal, quiet respiratory cycle.
118
What's the minimal volume?
a component of the residual volume, the amount of air that would remain in your lungs if they were allowed to collapse. The minimal volume ranges from 30 to 120 mL, but cannot be measured in a healthy person.
119
What is the total lung capacity?
the total volume of your lungs calculated by adding the vital capacity and the residual volume. This averages around 6000 mL in males and 4200 mL in females.
120
What's the residual volume?
the amount of air that remains in your lungs even after a maximal exhalation
121
What's the functional residual capacity (FRC)?
the amount of air remaining in your lungs after you have completed a quiet respiratory cycle. The FRC is the sum of the expiratory reserve volume and the residual volume.
122
What is The vital capacity?
the maximal amount of air that you can move into or out of your lungs in a single respiratory cycle. The vital capacity is the sum of the expiratory reserve volume, the tidal volume, and the inspiratory reserve volume.
123
What is the inspiratory capacity?
is the amount of air that you can draw into your lungs after you have completed a quiet respiratory cycle. The inspiratory capacity is the sum of the tidal volume and the inspiratory reserve.
124
Alveoli adaptations?
large surface area,
short diffusion distance
moist surface
125
The capillaries lining the alveoli have high concentration of ...
oxygen
126
Oxygen from the air easily diffuses from the alveoli into the blood through the...
thin barrier of the alveolus wall.
127
How does carbon dioxide leave the lungs?
1) the concentration of carbon dioxide is quite high in the blood,
2) the gas easily diffuses out into the alveolar space.
3) from here, the air that has comparatively more concentration of carbon dioxide leaves the lungs
128
What are the cells of the alveoli?
Type I Pneumocyte/ Type I alveolar cells
Type II Pneumocyte/Type II alveolar cells
Alveolar Macrophages
129
Describe Type I Pneumocyte/ Type I alveolar cells
* Flat squamous epithelial cells
* Thin & delicate
* 95% alveolar surface
* Allow for rapid gas diffusion
130
Describe Type II Pneumocyte/Type II alveolar cells
Cuboidal septal cells
Thick and narrow
Scattered between type I cells
5% alveolar surface
2 main functions:
Produce surfactant
Repair alveolar epithelium
131
Describe alveolar macrophages.
(dust cells)
- present in the alveoli lumen
- preserve alveoli integrity
- last line of defence - removes pathogens
132
Describe Type I Pneumocyte/Type I alveolar cells.
Flat squamous epithelial cells
Thin & delicate
95% alveolar surface
Allow for rapid gas diffusion
133
Describe Type II Pneumocyte/Type II alveolar cells.
Cuboidal septal cells
Thick and narrow
Scattered between type I cells
5% alveolar surface
2 main functions:
Produce surfactant
Repair alveolar epithelium
134
Describe alveolar macrophages.
(dust cells)
- present in the alveoli lumen
- preserve alveoli integrity
- last line of defence - removes pathogens.
135
How many binding sites does haemoglobin have?
Hemoglobin has four binding sites for oxygen molecules.
136
Where are the binding sites of hemoglobin located?
Each located in an iron atom in a heme group.
137
What is the trend in oxygen binding affinity of hemoglobin?
Increase in oxygen binding affinity from left to right, and a decrease in oxygen binding affinity from right to left.
138
The amount of oxygen that can bind to hemoglobin is known as ...
the oxygen-binding capacity.
139
Factors affecting binding from oxygen to hemoglobin.
✓pH
✓carbon dioxide
✓temperature
✓2,3-Bisphosphoglycerate
140
The amount of oxygen bound to the hemoglobin at any time is related to the...
partial pressure of oxygen.
141
How much oxygen is carried by haemoglobin (Hb) in RBC?
98.5%
142
How much oxygen is dissolved in plasma?
1.5%
143
If PO2 increases...
* Reaction above shifts to right
* More O2 gets bound to haem
* Saturation increases
144
If PO2 decreases...
* Reaction above shifts to left
* More O2 released
* Saturation decreases
145
What is the average resting PO2 at systemic capillaries?
40mmHg
146
What is the normal PO2 at pulmonary capillaries?
100mmHg
147
What is the Bohr effect?
- Increased CO2 levels lowers blood pH
- Hb molecule shape changes
- Lower pH causes Hb to release more O2
- Higher pH causes Hb to hold onto more O2
148
As temperature rises Hb releases more...
O2
149
As temperature rises Hb releases more O2. These effects are important for...
... active tissues where large amounts of heat are being generated.
150
Where is 2,3-Diphosphoglycerate (2,3-DPG) produced?
Produced in erythrocytes.
151
What does 2,3-Diphosphoglycerate (2,3-DPG) reduce?
Reduces Hb affinity for O2.
152
What does 2,3-Diphosphoglycerate (2,3-DPG) facilitate?
Facilitates the release of O2.
153
What is high altitude?
High altitude is the region of earth located at an altitude of above 8,000 feet from mean sea level.
## Footnote
People can ascend up to this level, without any adverse effect.
154
Air Composition does not...
vary with altitude.
155
Characteristic feature of high altitude is the...
low barometric pressure.
156
Characteristic feature of high altitude is the low barometric pressure. However, amount of oxygen is...
is same as that of sea level.
157
Due to low barometric pressure, partial pressure of gases, particularly oxygen ...
proportionally decreases.
158
Due to low barometric pressure, partial pressure of gases, particularly oxygen proportionally decreases. What does this lead to?
* It leads to hypoxia.
159
At what altitude does altitude sickness occur?
occurs above 2,500 metres in average.
160
What are the symptoms of altitude sickness?
Collection of nonspecific symptoms: flu, carbon monoxide poisoning, hangover, headache, nausea, vomiting, anorexia.
161
What is the amount of O2 in the air at high altitude?
The amount of O2 in the air remains at 21% but the barometric pressure decreases with altitude.
162
What stays the same and what decreases with altitude?
The amount of O2 in the air remains at 21% but the barometric pressure decreases with altitude.
163
What falls with increasing elevation?
the partial pressure of oxygen falls with increasing elevation.
164
How high up is the DEATH ZONE?
26,000 ft.
165
What is the PO2 of venous blood at 26,000 feet?
40 mmHg - incompatible with life.
166
As one ascends, PO2 starts to ...
... drop exponentially with altitude, reaching dangerous values at 50 mmHg.
167
What is the PO2 at sea level?
160 mmHg.
168
What is the PO2 at Lake Titicaca?
95 mmHg.
169
What is the PO2 at Lake Mt Everest?
53 mmHg.
170
Symptoms deteriorate with...
... increasing altitude.
171
How does the cardiorespiratory system adapt to high altitudes initially?
1) Increased cardiac output
2) Hyperventilation:
- increase respiration and tidal volume as the body tries to extract O2 from the air.
172
What does hyperventilation (because of high altitudes) result in?
Respiratory alkalosis: increased respiration elevates blood pH beyond the normal range (7.35-7.45) as a result of reduction in arterial CO2 levels.
173
What is the long-term compensation for low PO2?
✓ Increased haematocrit and blood volume (weeks)
✓ Increased diffusion capacity of lungs
✓ Increased capillarity in tissues
✓ O2 carrying capacity of blood – Polycythaemia
✓ O2 diffusion from blood to tissues
* Capillary density
* Increase in myoglobin concentration
* Tissue utilisation of O2
174
Why does low PO2 from high altitudes cause increased haematocrit?
* RBC production increases via erythropoietin – PO2 sensed– produced in kidneys– acts on hematopoietic stem cells
* Blood volume under hormonal control of kidneys.
175
Describe increased capacity of lungs.
✓ Increased capillary volume
✓ Increased lung volume
✓ Increased pulmonary pressure.
176
Describe increased capillarity in tissues.
✓ Stimulate angiogenesis – growth of new capillaries
✓ Feedback control in local tissue beds
✓ More effective in young people.
177
Describe O2 diffusion from blood to tissues.
Concentration of 2,3-diphosphoglycerate (DPG) in red blood cells increases within 24h of ascending in altitude.
## Footnote
DPG reduces the affinity of haemoglobin for oxygen thus facilitating oxygen release to the tissues.
178
Why changes in capillary density in high altitudes?
Reduces the diffusion distance for oxygen between the blood and the tissues.
179
Describe increase in myoglobin concentration at high altitudes.
There is an increase in the concentration of myoglobin that facilitates diffusion of O2 to the tissues.
180
Describe tissue utilisation of O2.
Muscle biopsies in acclimatized men show an increase in mitochondria and enzymes, associated with aerobic pathways.
181
Define acclimatization.
Refers to the adaptations or the adjustments by the body in high altitude.
182
While staying at high altitudes for several days to several weeks, a person slowly gets...
...adapted or adjusted to the low oxygen tension, so that hypoxic effects are reduced.
183
Describe native adaptation to high altitude.
– All the same compensations of acclimatization plus:
* Larger chest cavity
* Larger heart, especially right side
* Increased cellular efficiency to use O2.
184
What are high altitude disorders?
* Acute Mountain Sickness
* High Altitude Cerebral Oedema (HACE)
* High Altitude Pulmonary Oedema (HAPO)
185
What are symptoms of Acute Mountain Sickness (AMS)?
* Headache
* Nausea & Dizziness
* Loss of appetite
* Fatigue
* Shortness of breath
* Disturbed sleep
* General feeling of malaise.
186
Symptoms of mountain sickness can be partially eliminated by...
...breathing pure O2, which is why most climbers making ascents of peaks like Mt Everest use supplementary O2.
187
What is HACE?
A medical condition in which the brain swells because of the physiological effects of traveling to a high altitude.
188
In who does HACE usually appear?
In patients who have acute mountain sickness and involves disorientation, lethargy, and nausea among other symptoms.
189
When does HACE occur?
It occurs when the body fails to acclimatize while ascending to a high altitude.
190
HACE generally does not occur until...
...an individual has spent 48 hours at an altitude of 4,000 metres.
191
What is the rarity of HACE?
Rare: 0.5-1% above 4km.
192
What are symptoms of HACE?
- Hypoxia-induced vasodilatation, high capillary pressure and oedema
- Damage to BBB, causing microhemorrhages
✓ Fever
✓ Ataxia
✓ Photophobia
✓ Rapid heart beat
✓ Lassitude
✓ Confusion, Altered mental state
✓ Sufferers cease physical activities regardless of their necessity for survival
✓ Loss of consciousness.
193
What is the mortality rate of HAPE?
✓ High mortality rate.
194
How does HAPE occur?
Vasoconstriction in pulmonary capillaries leads to increased blood pressure in open capillaries leading to oedema.
195
What are the effects of HAPE?
a) Increased pulmonary hypertension secondary to hypoxic pulmonary vasoconstriction.
b) Idiopathic non-inflammatory increase in the permeability of the vascular endothelium.
