Resp Physiology 2 Flashcards

1
Q

What does Boyle’s Law state?

A

At a constant temperature, pressure (P) and volume (V) are inversely proportional. P1V1 = P2V2.

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2
Q

What does Charles’ Law state?

A

At constant pressure, volume (V) is proportional to temperature (T). V1/T1 = V2/T2.

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3
Q

What does Dalton’s Law state?

A

The total pressure of a gas mixture is the sum of the partial pressures of its individual gases.

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4
Q

How does water vapor affect inspired gas?

A

Fully humidified air in the airways at 37°C exerts a vapor pressure of 6.3 kPa, diluting other gases.

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5
Q

What is the Alveolar Gas Equation?

A

PAO2 = FiO2 (PB - PH20) - (PaCO2/RQ)

PAO2 = Alveolar O2
FiO2 = Fraction of inspired O2
PB = Barometric pressure
PH2O = Water vapor pressure
PaCO2 = Arterial CO2
RQ = Respiratory Quotient (~0.8)

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6
Q

What does Henry’s Law state?

A

The amount of gas dissolved in a liquid is proportional to its partial pressure and solubility.

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7
Q

What does Graham’s Law state?

A

The rate of diffusion of a gas is inversely proportional to the square root of its molecular weight.

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8
Q

What factors influence gas diffusion across membranes?

A

Greater surface area and partial pressure difference (ΔP) increase diffusion; increased membrane thickness reduces it.

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9
Q

How is oxygen transported in the blood?

A

Oxygen is transported in two forms: bound to hemoglobin (Hb) and dissolved in plasma.

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10
Q

How much O₂ does hemoglobin (Hb) carry?

A

Each gram of Hb can carry 1.34 ml O₂, and at full saturation, ~200 ml O₂ per L of blood.

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11
Q

How much O₂ is dissolved in plasma?

A

Only ~3 ml O₂ per L of plasma at 13 kPa O₂, making Hb the primary O₂ carrier.

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12
Q

What factors shift the O₂-Hb curve to the right?

A

Decreased pH

increased CO₂

increased temperature

increased 2,3-DPG (Bohr effect).

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13
Q

What factors shift the O₂-Hb curve to the left?

A

Increased pH

decreased CO₂

decreased temperature

decreased 2,3-DPG

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14
Q

How do you calculate total oxygen content in blood?

A

CaO2 = (1.39xHbxSaO2x0.01) + (0.023xPaO2)

CaO2 = Arterial O2 content
1.34 = Max O2 carrying capacity of blood
Hb = Haemoglobin
SaO2 = Oxygen saturation
PaO2 = Arterial oxygen pressure
0.023 = solubility constant of oxygen

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15
Q

What is the Bohr Effect?

A

A decrease in pH or increase in CO₂ (PaCO₂) reduces Hb’s oxygen affinity, facilitating O₂ unloading in tissues.

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16
Q

What is the Haldane Effect?

A

Oxygenation of hemoglobin reduces its ability to bind CO₂, promoting CO₂ release in the lungs.

17
Q

What are the three forms of CO₂ transport?

A

CO₂ is transported as bicarbonate (HCO₃⁻)

carbaminoheamoglobin compound bound to Hb

dissolved in plasma

18
Q

How is CO₂ transported as bicarbonate (HCO₃⁻)?

A

CO₂ reacts with water to form carbonic acid (H₂CO₃), which dissociates into H⁺ and HCO₃⁻.

19
Q

How is CO₂ transported as carbamino compounds?

A

CO₂ binds to proteins, mainly hemoglobin, forming carbaminohemoglobin.

20
Q

How is CO₂ transported dissolved in plasma?

A

CO₂ is ~20 times more soluble than O₂, allowing a small but significant portion to be directly dissolved.

21
Q

What is a V/Q mismatch?

A

An imbalance between alveolar ventilation (V) and perfusion (Q), leading to inefficient gas exchange.

22
Q

What is a right-to-left shunt?

A

Blood bypasses ventilated alveoli, leading to hypoxia that does not improve with 100% O₂.

23
Q

What is physiological dead space?

A

The sum of anatomical dead space (conducting airways) and alveolar dead space (ventilated but unperfused alveoli).

24
Q

What do central chemoreceptors detect?

A

PaCO₂ and pH changes in cerebrospinal fluid.

25
Q

What do peripheral chemoreceptors detect?

A

PaO₂, PaCO₂, and pH changes in blood.

26
Q

Pulmonary Receptors – Stretch Receptors

A

Inhibit overinflation (Hering-Breuer reflex).

27
Q

Pulmonary Receptors – Irritant Receptors

A

Respond to noxious stimuli, triggering bronchoconstriction and coughing.

28
Q

Pulmonary Receptors – J-Receptors

A

Respond to pulmonary congestion, triggering rapid shallow breathing.

29
Q

Pulmonary Receptors – Bronchial C-Fibers

A

React to inflammatory mediators, causing bronchoconstriction and mucus secretion.