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PHYSIOLOGY > Respiratory Phys6 > Flashcards

Respiratory Phys6 Flashcards

(73 cards)

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1
Q

Conducting zone

A

From trachea & ends up to terminal bronchi 16th division
No exchange of gases considered as anatomical dead space abt 150 ml

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2
Q

Respiratory zone

A

17th to 23rd zone
exchange of gases takes place
Vol. of this zone varies from 3-4 L

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3
Q

Respiratory unit

A

Each respiratory unit consists :
1 respiratory bronchiole
opens into
no. of alveolar ducts
each alveolar duct into
several alveoli

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4
Q

How r alveoli kept dry

A

Factors keep alveoli dry :
• Low pulmonary capillary pressure (8 -10 mm hg) with colloidal pressure of 25 mm hg
• reduction of surface tension by surfactant
• removal of leaked proteins into lymphatic capillaries

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5
Q

How Bronchial tone affected by circadian rhythm

A

Circadian rhythm alters branchial tone
It’s max constriction at 6 am & max dilatation at 6 pm.

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6
Q

Structural components of alveolo capillary membrane

A

Consist of following structures from inside - outside:
1. Surfactant
2. Thin layer of H2O
3. Alveolar epithelium
4. Basement membrane of alveolus & capillary
5. Endothelial cell layer
Thickness from 0.3 to 1.0 micrometer

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7
Q

Role of lymphatic system of lungs

A

Lung lymphatic system prevents pulmonary edema by removing filtered proteins

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8
Q

What are the primary functions of the respiratory system?

A

Gas exchange, acid-base balance, phonation, immune defense, metabolism of vasoactive
substances.

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9
Q

Define lung compliance.

A

The ability of the lungs to expand per unit pressure change; C = change in V / change in P.

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10
Q

: What is the normal tidal volume in an adult?

A

~500 mL.

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11
Q

: Define physiological dead space.

A

Anatomical dead space + alveolar dead space

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12
Q

What is the Bohr effect?

A

Principle : amt of CO2 present in expired air is equal to sum of CO2 present in dead space air+ alveolar air

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13
Q

normal atmospheric pressure at sea level?

A

760 mmHg.

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14
Q

role of surfactant

A

Reduces alveolar surface tension, preventing collapse

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15
Q

muscles are used in quiet inspiration?

A

Diaphragm and external intercostals.

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16
Q

Hering-Breuer reflex

A

Prevents lung overinflation by inhibiting inspiratory drive when lungs are overstretched.

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17
Q

lung compliance in emphysema and fibrosis

A

Increased in emphysema, decreased in fibrosis

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18
Q

intrapleural pressure at the end of expiration.

A

~ -5 cm H2O.

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19
Q

: What happens to airway resistance in chronic obstructive pulmonary disease (COPD)

A

Increased due to airway narrowing and mucus secretion.

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20
Q

Define Fick’s law of diffusion

A

Rate of diffusion is proportional to (Surface area x Partial pressure difference) / (Thickness of
membrane).

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21
Q

normal PaO2 and PaCO2 in arterial blood

A

PaO2: 95-100 mmHg, PaCO2: 40 mmHg

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22
Q

How does CO2 transport occur in the blood

A

70% as bicarbonate, 20% bound to hemoglobin, 10% dissolved.

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23
Q

What is the chloride shift

A

Exchange of Cl- for HCO3- in RBCs to maintain electrochemical balance

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24
Q

normal V/Q ratio

A

0.8 (ventilation = 4 L/min, perfusion = 5 L/min).

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25
What happens to V/Q ratio in pulmonary embolism?
: Increased (dead space ventilation).
26
What happens to V/Q ratio in airway obstruction?
Decreased (shunting)
27
v: What is the primary stimulus for respiration?
Increased PaCO2 detected by central chemoreceptors.
28
Where are peripheral chemoreceptors located?
: Carotid and aortic bodies.
29
What is the primary abnormality in obstructive lung disease?
Increased airway resistance, difficulty exhaling
30
How does hypoxia differ from hypoxemia?
: Hypoxia: Low O2 in tissues; Hypoxemia: Low O2 in blood.
31
What is Kussmaul breathing?
Deep, labored breathing seen in metabolic acidosis (e.g., diabetic ketoacidosis).
32
What is the main cause of hypercapnia
Alveolar hypoventilation.
33
What is the FEV1/FVC ratio in obstructive vs. restrictive lung diseases
Obstructive: <70%, Restrictive: Normal or increased.
34
What is peak expiratory flow rate (PEFR) used for
Assessing airway obstruction severity in asthma and COPD
35
How does respiratory acidosis occur
: Hypoventilation leads to CO2 retention, decreasing pH.
36
What compensatory mechanism occurs in metabolic acidosis?
Increased respiratory rate (Kussmaul breathing).
37
What is the primary adaptation to high altitude?
Increased ventilation and erythropoiesis.
38
What is decompression sickness
: Nitrogen bubbles form in blood due to rapid ascent after deep diving.
39
primary function of the respiratory system
To facilitate gas exchange by delivering oxygen to the blood and removing carbon dioxide.
40
main components of the respiratory system
Nose, pharynx, larynx, trachea, bronchi, bronchioles, alveoli, lungs, and respiratory muscles.
41
Define pulmonary ventilation
It is the movement of air into and out of the lungs, enabling gas exchange.
42
What is the normal respiratory rate in adults
2–16 breaths per minute
43
What is dead space
The volume of air in the respiratory passages that does not participate in gas exchange (about 150 mL in adults)
44
What muscles are involved in inspiration
Diaphragm and external intercostal muscles.
45
What is the role of the diaphragm in breathing
It contracts and flattens during inspiration, increasing thoracic volume.
46
lung compliance
The ease with which the lungs expand during inspiration, defined as the change in lung volume per unit change in transpulmonary pressure.
47
How does surfactant reduce surface tension in alveoli?
It reduces surface tension by breaking intermolecular forces, preventing alveolar collapse.
48
What is the physiological significance of intrapleural pressure?
It is always negative, helping to keep the lungs expanded.
49
Define tidal volume (TV
The amount of air inspired or expired during normal breathing (≈500 mL).
50
What is vital capacity (VC)
The maximum volume of air that can be exhaled after maximum inspiration (≈4.5 L in adults).
51
What is functional residual capacity (FRC)
The volume of air remaining in the lungs after a normal expiration (≈2.5 L).
52
How is total lung capacity (TLC) calculated?
TLC = VC + RV (Residual Volume)
53
What is the significance of residual volume (RV)?
Prevents lung collapse by keeping alveoli open after expiration.
54
Where does external respiration occur
In the alveoli, where oxygen diffuses into blood and CO₂ diffuses out.
55
What is the normal arterial PO₂ and PCO₂
PO₂: 95–100 mmHg, PCO₂: 40 mmHg.
56
What is the oxygen dissociation curve?
A graph showing the relationship between PO₂ and hemoglobin saturation.
57
What shifts the oxygen dissociation curve to the right?
Increased temperature, PCO₂, H⁺ (Bohr effect), and 2,3-BPG.
58
What is the Bohr effect?
A shift of the oxygen dissociation curve due to changes in pH and CO₂ concentration, enhancing O₂ unloading in tissues.
59
Where is the respiratory center located
In the medulla oblongata and pons.
60
What is the role of the central chemoreceptors
They respond to changes in CO₂ and H⁺ levels in cerebrospinal fluid.
61
How do peripheral chemoreceptors regulate breathing?
They detect changes in PO₂, PCO₂, and pH in the blood and signal the medulla to adjust respiration.
62
What is the Hering-Breuer reflex
A reflex preventing overinflation of the lungs via stretch receptors in the airways
63
What happens in hypercapnia
Elevated CO₂ levels stimulate increased ventilation to remove excess CO₂.
64
What is the cause of respiratory acidosi
Hypoventilation leading to CO₂ retention and a decrease in blood pH.
65
How does hypoxia affect the body?
It reduces oxygen delivery to tissues, leading to symptoms like cyanosis and dyspnea.
66
What is obstructive lung disease?
A condition causing airway narrowing, leading to increased resistance (e.g., COPD, asthma)
67
How does restrictive lung disease differ from obstructive disease
Restrictive lung diseases reduce lung expansion and compliance (e.g., fibrosis).
68
What is ARDS (Acute Respiratory Distress Syndrome)?
A severe condition caused by alveolar damage, leading to impaired gas exchange and hypoxia.
69
Why does carbon monoxide (CO) poisoning occur
CO binds to hemoglobin with high affinity, reducing oxygen transport.
70
What is Kussmaul breathing?
Deep, rapid breathing seen in metabolic acidosis (e.g., diabetic ketoacidosis)
71
What is the effect of altitude on respiration?
At high altitude, low PO₂ stimulates hyperventilation and increased erythropoietin production.
72
What is cyanosis?
A bluish discoloration of the skin due to deoxygenated hemoglobin >5 g/d
73
What is the normal A-a gradient
–10 mmHg; an increased gradient indicates a diffusion problem or shunting.

PHYSIOLOGY (6 decks)

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