Chapter 17 Flashcards by Hope Carr

List 4 major functions of the respiratory system.

1) exchange of gases btw the atmosphere +
blood
2) homeostatic regulation of body pH
3) protection from inhaled pathogens +
irritating substances
4) vocalization

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Explain the function of the pleural cavity.

fluid in the cavity that allows for the parietal and visceral layers to slide past each other with a reduced amount of friction

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Explain the function of the pleural sac.

(a double membrane) that surrounds the lung

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Explain the function of the external intercostals.

help with inspiration by pulling the ribcage out

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Explain the function of the diaphragm.

brings the floor of the thoracic cavity down during inspiration

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Explain the function of the type I alveolar cells.

gas exchange

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Explain the function of the type II alveolar cells.

produce surfactant

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Explain the function of connective tissue.

elastin + collagen –> close association w/ capillaries

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List the pathway for the pulmonary circulation from high flow to low flow.

1) right ventricle
2) pulmonary trunk
3) pulmonary arteries
4) lungs
5) pulmonary veins
6) left atrium

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Explain mathematically the relationship between atmospheric pressure and the partial pressures of individual gases.

partial pressure of N2 –> higher in
atmosphere
partial pressure of O2 –> higher in
atmosphere
partial pressure of CO2 –> higher in alveoli
partial pressure of H2O –> higher in alveoli

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Explain the relationship between the pressure of a gas and the volume in which it is contained.

PV = nRT
V = 1/P –> inverse relationship

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What is the equation to find partial pressure of a gas?

P(atm) x (% of gas in atmosphere)

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What is Boyle’s Law?

P1V1 = P2V2

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Define + describe lung volumes.

how much air is moved

respiratory cycle = 1 inspiration followed by 1
expiration

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Define lung capacity.

sums of 2 or more volumes

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What is used to measure lung volume?

spirometer

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What are the 4 lung volumes.

1) V(T) = tidal volume
2) IRV = inspiratory reserve volume
3) ERV = expiratory reserve volume
4) RV = residual volume

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What are the 4 lung capacities?

1) inspiratory capacity = V(T) + IRV
2) vital capacity = V(T) + IRV + ERV
3) total lung capacity = V(T) + IRV + ERV + RV
4) functional residual capacity = ERV + RV

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When does inspiration occur?

when alveolar pressure decreases

When does expiration occur?

when alveolar pressure increases

Explain how pressures and lung volumes change during normal breathing, and how that affects airflow in the respiratory system.

Alveolar Pressure:
- begins at 0 = atmospheric pressure
- inspiration –> goes negative, then back to 0 (when the pressure btw atmosphere and alveoli are equal)
- expiration –> goes positive, then back to 0

Intrapleural Pressure:
- normally negative pressure (-3 mm Hg)
- inspiration –> starts around -3 and ends around -6 (pressure drops)
- expiration –> lung pressure decreases (pressure goes back to the normal value)

Volume of Air Moved:
- inspiration –> volume increases
- expiration –> volume decreases

Explain the role that subatmospheric intrapleural pressure plays in normal breathing.

subatmospheric pressure in pleural cavity keeps the lungs inflated

Graph the alveolar + intrapleural pressure changes that occur during one respiratory cycle.

Compare + contrast compliance and elastance in respiratory physiology.

compliance –> ability to stretch
- high compliance = stretches easily
- low compliance = requires more force

elastance –> ability to return to resting volume when stretching force is released

Explain the role of surface tension in respiratory physiology.

easier to expand the alveoli when the water molecules are not trying to stick to one another

Explain the role of surfactants in respiratory physiology.

- reduces surface tension --> so that the alveoli fluid doesn't promote collapse - helps increase compliance - smaller alveoli have more surfactants than larger alveoli

Map the factors affecting airway resistance, with emphasis on local and reflex control mechanisms involved in bronchodilation and bronchoconstriction.

R = Ln/r^4 bronchodilation --> decreases resistance - sympathetic: epinephrine binds to B2 receptors on smooth muscle - local control --> CO2 - long distance control --> epinephrine bronchoconstriction --> increases resistance - parasympathetic: Ach binds to muscarinic receptors on smooth muscle - local control --> histamine + leukotrienes - long distance control --> parasympathetic neurons

What is the formula to find total pulmonary ventilation?

ventilation rate x tidal volume (Vt)

What is the formula to find alveolar ventilation?

ventilation rate x (tidal volume - dead space volume)

Explain why gas composition in the alveoli remains relatively constant during normal breathing.

the amount of oxygen entering the alveoli equals the amount of oxygen leaving to enter the blood

Explain how alveoli change with hyper- and hypoventilation.

- hyperventilation --> increasing alveolar ventilation --> oxygen partial pressure increases + CO2 partial pressure decreases - hypoventilation --> decreasing alveolar ventilation --> oxygen partial pressure decreases + CO2 partial pressure increases

Explain the local control mechanisms by which ventilation and alveolar blood flow are matched.

ventilation perfusion matching --> perfusion of blood past alveoli is matched to alveolar ventilation to maximize gas exchange

What is the normal alveolar partial pressure of oxygen?

100 mm Hg

What is the normal alveolar partial pressure of carbon dioxide?

40 mm Hg

What happens when the alveoli do not have good exchange?

- pressure of CO2 increases and pressure of O2 decreases - blood going to that area of the lungs is not getting oxygenated

In systemic arteries, what happens when the pressure of CO2 increases?

dilation

In systemic arteries, what happens when the pressure of CO2 decreases?

constriction

In systemic arteries, what happens when the pressure of O2 increases?

constriction

In systemic arteries, what happens when the pressure of O2 decreases?

dilation

In pulmonary arteries, what happens when the pressure of CO2 increases?

weak response of constriction

In pulmonary arteries, what happens when the pressure of CO2 decreases?

weak response of dilation

In pulmonary arteries, what happens when the pressure of O2 increases?

weak response of dilation

In pulmonary arteries, what happens when the pressure of O2 decreases?

constriction

In bronchioles, what happens when the pressure of CO2 increases?

dilation

In bronchioles, what happens when the pressure of CO2 decreases?

constriction

In bronchioles, what happens when the pressure of O2 increases?

weak response of constriction

In bronchioles, what happens when the pressure of O2 decreases?

weak response of dilation