1. Chapter 21 Control of Respiratory Function
Essentials of Pathophysiology
Chapter 21 Control of Respiratory Function

2. Pre lecture quiz F
Pulmonary ventilation is the movement of blood through the lungs.
Deoxygenated blood leaves the right heart through the pulmonary veins.
The peripheral chemoreceptors monitor arterial oxygen levels and will stimulate respirations when the PO2 has dropped below 60 mm Hg.
Lung compliance refers to the ease with which the lungs can be inflated.
The effects of airway resistance on airflow can be illustrated by using Poiseuille’s law, which states that resistance to flow is inversely related to the fourth power of the radius. F T T T

3. Pre lecture quiz Diffusion dissociation peripherial Surfactant
Vasoconstriction
__________ exerts very important effects on lung inflation, including lowering the surface tension, increasing lung compliance and ease of inflation, and assisting in preventing pulmonary edema by keeping the alveoli dry.
The relation between the oxygen carried in combination with hemoglobin and the PO2 of the blood can be described using the oxygen–hemoglobin __________ curve.
The most important chemoreceptors for sensing changes in blood carbon dioxide content are the __________ chemoreceptors.
__________ refers to the movement of gases in the alveoli and across the alveolar–capillary membrane.
The blood vessels in the pulmonary circulation undergo marked ________________ when they are exposed to hypoxia.

4. Lung Functions Gas exchange Moves O2 into blood Removes CO2 from blood
Blood storage
Regulate vasoconstricting substances
Bradykinin-
Angiotensin II
Heparin-
formed locally in injured tissue, acts in vasodilation of small arterioles, is considered to play a part in inflammatory processes
sulfuric acid ester that occurs especially in the liver and lungs, that prolongs the clotting time of blood by preventing the formation of fibrin
obtained from the liver and lungs of domesticated food animals
protamine sulfate- is a heparin antagonist

5. Conducting Airways Move air into lungs Warm and humidify air
Trap inhaled particles (Mucus escalator)

6. Conducting & respiratory Airways
Note Change of Cell Type & Thinning of Air to Blood Distance
Author: Please add title.

7. Membranes and Cavities
Parietal pleura
Visceral pleura
Pleural space (between pleurae)
Mediastinum

8. Respiratory Airways Bronchioles Alveoli
Gas is exchanged with the blood

9. Question
Which serous membrane lines the thoracic cavity?
Viscera pleura
Parietal pleura
Visceral mediastinum
Parietal mediastinum

10. Answer
Parietal pleura
The organs and walls of the thoracic and abdominal cavities are covered with serous membranes. Visceral membranes cover the organ; parietal membranes line the cavity walls. The two membranes and the space between them allow for ease of movement.
The thoracic cavity is lined by parietal pleura; the lungs are covered by visceral pleura.

11. Respiratory Muscles Diaphragm Accessory muscles of inhalation
External intercostals
Scalene
Sternocleidomastoid
Accessory muscles of exhalation
Internal intercostals
Abdominal muscles

12. Question
Tell whether the following statement is true or false: During inhalation, the diaphragm contracts and flattens.

13. Answer
True The diaphragm is the main muscle of inhalation/inspiration. During inhalation, the diaphragm contracts and flattens (it moves downward in order to accommodate the volume of air you are taking in, allowing space for the lungs to expand). During exhalation, the diaphragm relaxes and moves back up.

14. Compliance How easily lungs can be inflated depends on:
Elastin and collagen fibers
Water content
Surface tension

15. Surfactant Reduces Surface Tension

16. Scenario: Question: A man’s lungs were damaged during a fire
He developed severe respiratory distress
The doctor said smoke inhalation had caused an inflammation of his alveoli
The damage had also destroyed some of his surfactant
Question:
What had happened to his lung compliance?
Why was he given positive-pressure ventilation?

17. Lung Volumes
Time

18. Lung Capacities Vital capacity Inspiratory capacity
Functional residual capacity
Total lung capacity

19. Lung Volumes Tidal volume Inspiratory reserve Expiratory reserve
Residual volume

20. Dynamic Lung Function Forced vital capacity Forced expiratory volume
FEV1.0
Minute volume
Maximum voluntary ventilation

21. Forced vital capacity MMEF =Mean Mid Expiratory Flow Matching:
Normal expiration
Obstructive expiration
Restricted Lungs
A B C
Volume diagram A B C
Flow diagram

22. Question
Which measure of lung function indicates the total amount of air that the lungs can hold?
Tidal volume
Functional residual capacity
Vital capacity
Total lung capacity

23. Answer
d. Total lung capacity is the maximum amount of air that the lungs can hold—everything (volume-wise) at the end of a maximal inhalation (the deepest breath one can possibly take). Normal TLC is approximately 6 L.

24. Gas Exchange Oxygen moves from alveolar air into blood
Carbon dioxide moves from blood into alveolar air

25. Ventilation and Perfusion
Scenario:
A child has inhaled a peanut, blocking her left primary bronchus.
Question:
How will the ventilation in her two lungs change?
How will the composition of the air in her two lungs differ?
Which lung should she send more blood to?
How should her body alter perfusion of the lungs?

26. Ventilation–Perfusion Mismatching
In mismatch Blood goes to parts of the lung that do not have oxygen, and
Blood does not go to parts of the lung that have oxygen
In normal function blood perfusion is routed opposite of other body tissues.
Blood with no air
Air with no Blood
Air and blood

27. Question
Tell whether the following statement is true or false: Ventilation-perfusion mismatch results in hypoxia.

28. Answer
True In either case (ventilation without perfusion or perfusion without ventilation) oxygen is not picked up by the capillaries and delivered to the tissues. The result of decreased oxygen at the tissue level is termed hypoxia.

29. Blood Gases—Oxygen Dissolved oxygen = PaO2 or PO2
Normal value >80 mm Hg
Oxygen bound to hemoglobin = oxyhemoglobin
Normal value 95% to 97% saturation

30. Hemoglobin Holds 4 Oxygen Molecules
How saturated is this molecule of hemoglobin?
How could a person have a hemoglobin saturation of 95%?
Author: Add text?

31. Oxygen Capacity Amount of oxygen the blood can hold
What is the oxygen capacity of normal blood?
What is the oxygen capacity of anemic blood?
mg/dL
mg/dL

32. Oxygen Release
If the blood released half of its oxygen to the tissues …
How much oxygen would the normal tissues receive?
How much would the anemic person's tissues receive?

33. Oxygen Release (cont.) Most body tissues have a PO2 of 40-60 mm Hg
How much oxygen does the normal blood release at a PO2 of 40 mm Hg?
The anemic blood?
Author: Add text?

34. Factors that shift the curve:
Oxygen Affinity
How tightly the hemoglobin holds onto the oxygen
Which of these hemoglobin samples has the highest oxygen affinity?
Which will release the most oxygen to the tissues? A B C
PO2
Factors that shift the curve:
CO2, pH, DPG, Fetal Hb

35. Blood Gases—Carbon Dioxide
Dissolved carbon dioxide = PaCO2 or PCO2
Normal value 35–45 mm Hg
Carbon dioxide bound to hemoglobin = carbaminohemoglobin
Carbonic acid  bicarbonate ion and H+
When you exhale you remove CO2 from your blood and also decrease the amount of carbonic acid, raising your blood pH
CO2 + H2O H2CO3 H+ + HCO3-

36. Question
Tell whether the following statement is true or false: The relationship between PCO2 and pH is direct.

37. Answer
False
The relationship is indirect. As PCO2 levels rise, the amount of carbonic acid in the blood increases, making the pH more acidic (decreasing it).
CO2 + H2O H2CO3 H+ + HCO3-
pH=𝑙𝑜𝑔 1 [ 𝐻 + ]

38. Respiratory Control lungs inflate stretch receptors
note increased lung
begins inspiration
volume
pneumotaxic
respiratory
apneustic
centers
stretch receptors
stops inspiration;
note decreased lung
begins exhalation
volume
lungs
deflate

39. Chemoreceptors Can Adjust Respiration Rate
Central chemoreceptors
Measure PCO2 and pH in cerebrospinal fluid
Increase respiration when PCO2 increases or pH decreases
Peripheral chemoreceptors
Measure PO2 in arterial blood
Increase respiration when PO2 <60 mm Hg

40. Scenario
You are caring for a COPD client…
He has chronically high PCO2
He is being given low-flow oxygen and complains all the time that he “needs more air,” so you turn up his oxygen.
Question:
When you check on him later, he is unconscious and not breathing. What happened?