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CHAPTER 19: RESPIRATORY SYSTEM OBJECTIVES:

1. Name the organs and functions of the respiratory system.

Organs Functions

1. Nose/External Nares

2. Nasal Cavity

3. Pharynx

4. Larynx

5. Trachea

6. Bronchial Tree within Lungs

7. Paranasal Sinuses

8. Diaphragm

1 exchange of gases 2 voice production 3 blood pH homeostasis

2. Name the 5 parts of respiration (You will define these in later questions).

Pulmonary ventilation

External respiration

Transport of gases

Internal respiration

Cellular respiration

3. Describe the significance of oxygen and carbon dioxide in human cells.

Oxygen is required by animal cells to perform cellular respiration which releases energy from nutrients. A waste-product of CR is carbon dioxide.

3. Explain the structure and function of mucous membranes that line most of the respiratory tract. Specifically name the tissue that lines the trachea.

Mucous membranes (mm) are moist membranes that warm, moisten, and filter incoming air. Goblet cells secrete mucus which protects. Specifically in the trachea the mm is pseudostratified columnar epithelium (PSCET), where mucus coated cilia trap debris and cilia beat debris up and out of airway.

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5. Locate the upper respiratory organs on the diagram below, describe their structure and any specific functions they may have (both respiratory and other functions, if applicable).

All are lined by mucous membranes that warm, filter, and moisten incoming air. Nose composed of bone and cartilage has macroscopic hairs to trap debris; nasal cavity is divided into two by nasal septum and into three passageways on each side by nasal conchae; paranasal sinuses are continuous with nasal cavity; pharyx is divided into nasopharynx, oropharynx, and larynopharynx; larynx is composed of several hyaline cartilage components and one elastic cartilage structure called the epiglottis. The larynx also contains vocal cords producing speech

6. Name the four skull bones that contain sinuses and label them below.

Frontal, ethmoid, sphenoid, and maxillary

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7. Name the three parts of the pharynx and label them in the diagram below.

Nasopharynx, oropharynx, and laryngopharynx

8. Explain the significance of the epiglottis and glottis. Label the epiglottis above.

The epiglottis closes the airway during swallowing and the glottis is the slit-like space between the vocal cords through which air passes

9. Give the scientific name for the "Adam's Apple", and label it in the diagram below.

Thyroid cartilage

10. Describe how and where sound originates and how it is then converted into recognizable speech.

Sound originates when expelled air penetrates the vocal cords causing them to vibrate. The cerebral cortex allows for speech initiation, and Broca’s areas stimulate the muscles necessary for speech. The sinuses act as resonating chambers.

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11. Locate the lower respiratory organs on the diagram below, and describe the structure and any specific functions each may have.

Trachea’s hyaline cartilage supports airway and PSCET warms, filters and moistens with its cilia; primary bronchi (to each lung), secondary bronchi (to each lobe) and tertiary bronchi continue to warm….and distribute air

Terminal bronchioles are a regulation site determining the amount of air allowed into the lung lobule; alveoli allow for gas exchange.

12. Define the terms C-ring, trachealis muscle, and carina. Label carina above.

C-rings are named for the C shape of the rings of hyaline cartilage of trachea; the trachealis muscle completes the C-ring anterior to the esophagus; carina is the point of bifurcation (i.e. fork in the road) of the trachea into the lungs.

13. Name the type of cartilage that composes the trachea wall. HYALINE CARTILAGE

14. Distinguish between a primary, secondary, and tertiary bronchus, and label in the diagram above.

Primary bronchi to each lung, secondary bronchi to each lobe and tertiary bronchi further subdivide air.

15. Explain what happens to the epithelial lining, cartilage and smooth muscle of the bronchi as they branch deep into the lungs to form terminal bronchioles.

Epithelium is reduced to simple columnar ET, cartilage decreases and smooth muscle increases.

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16. Explain the effects that histamine and epinephrine have on terminal bronchioles.

Histamine causes bronchoconstriction; epinephrine causes bronchodilation

17. Discuss the structure and function of the pleural membranes.

The visceral and parietal pleural membranes are serous membranes = simple squamous ET over loose areolar connective tissue (LACT). The serous fluid (watery with high surface tension) between them essentially glues the two membranes together and they act as one which aids in inspiration.

18. Distinguish between a lobe and lobule of the lung and label each on the diagram below.

There are five lung lobes; three on the right and two on the left. There are many lung lobules where each receives a respiratory bronchiole, is surrounded by elastic CT, and houses a pulmonary artery and a pulmonary vein.

19. Discuss the microscopic anatomy of the lung, and label the tissue components below.

The alveolar walls are composed of simple squamous ET plus its basement membrane.

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20. Track a breath of air from the nose to an alveolus, noting what happens to the air as it meets each structure (16 steps)

Nose Secondary bronchus

Nasal cavity Tertiary bronchus

Nasopharynx Interlobular bronchiole

Oropharynx Terminal bronchiole

Laryngopharynx Respiratory bronchiole

Larynx Alveolar duct

Trachea Alveolar sac

Primary bronchus Alveolus

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21. Distinguish between Type I and Type II alveolar cells, in terms of structure and function and label each in the diagram below.

Type I alveolar cells are the wall cells while type II secrete surfactant

22. Define the term surfactant and describe its important function.

Surfactant, secreted by Type II alveolar cells is composed of phospholipids (fat,) and it functions to reduce the surface tension during expiration, preventing recoiling of the alveoli upon themselves.

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23. The Anatomy & Physiology of the Respiratory Membrane (RM). a. Draw a sketch of the RM, and label all parts (including specific tissue components and membrane thickness). b. Provide the scientific name of the scientific process that occurs through the RM, and define that process. c. Illustrate what occurs through this membrane using partial pressure values of gases involved and arrows designating gas flow. d. Finally, explain the fate of the transported gases involved.

Oxygen diffuses through the RM from the alveolus into the blood in the lung capillary where it is transported back to the heart for distribution to the body, and carbon dioxide diffuses through the RM from the blood in the lung capillary into the air in the alveolus where it is expelled.

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24. Define the term pulmonary ventilation, and describe its two actions in terms of forces, muscles, and membranes involved.

Pulmonary ventilation is breathing. The two actions in pulmonary ventilation include inspiration and expiration. Inspiration is due to atmospheric pressure and expiration is due to elastic recoil. The diaphragm and intercostal muscles are involved.

25. Starting with the diaphragm muscle in its relaxed position, describe in order,

the events that occur during inspiration.

1. The diaphragm contracts and pushes downward

2. The size of the thoracic cavity increases

3. The pressure within the thoracic cavity decreases to 758 mmHg (Boyle’s law)

4. Air rushes into and inflates the lungs (Dalton’s law)

26. Explain how Boyle's Law relates to ventilation.

Boyle’s law states that the pressure of gas is inversely proportional to the volume of the gas. As the size (volume) of the thoracic cavity increases, the pressure within the thoracic cavity decreases to from 760 to 758 mm Hg.

27. Explain why the serous fluid between the pleural membranes has such high

surface tension.

Serous fluid is composed primarily of water whose molecules are very cohesive resulting in high surface tension.

28. Define the term atelectasis, explain what is usually lacking within the alveoli

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when it occurs, and name the disease of premature newborns when it occurs.

Atelectasis is collapsed lung. Premature infants lack surfactant which functions to overcome the high surface tension within the alveoli. This is called respiratory distress syndrome.

29. Name the instrument used to measure lung volumes.

Spirometer

30. List, define, give estimate values, and correlate the six different lung volume

measurements shown in the graph below.

Tidal volume (TV) is the normal volume inspired and expired.

Vital capacity (VC) is TV + IRV + ERV

Inspiratory reserve volume (IRV) is the volume of air one can forcibly inhale after a normal tidal inspiration.

Residual volume (RV) is the volume of air that always remains in the lungs.

Expiratory reserve volume (ERV) is the volume of air one can forcibly exhale after a normal tidal expiration.

Total lung capacity is VC + RV.

31. State Dalton's Law and explain its significance in respiration.

Dalton’ s law states that gases diffuse from where they are in high pressure to where they are in low pressure. During inspiration, the pressure of the gas in the thoracic cavity falls to 758 mm Hg, so air rushes from the outside where its pressure is 760 into the alveoli.

32. List the percentages of N2, O2, and CO2 in air.

Nitrogen = 78%; oxygen is 21%; and carbon dioxide is less than 1%.

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33. Define what is meant by the partial pressure (pp) of a gas in a mixture and list the pp values of O2 and CO2 in air and in the lung capillaries.

Air is a mixture of gases, which is 21% oxygen and less than 1% carbon dioxide. In a mixture of gases, each gas exerts a partial pressure toward the total gas pressure, and the partial pressure of a gas is directly proportional to its concentration. The partial pressure of oxygen in the air in the alveolus is 104 mmHg and the partial pressure of oxygen in the lung capillary is 40 mmHg. Consequently, oxygen diffuses through the RM from the alveolus into the blood in the lung capillary where it is transported back to the heart for distribution to all body cells. Conversely, the partial pressure of carbon dioxide in the lung capillary is 45 mm Hg and the partial pressure of carbon dioxide in the air in the alveolus is 40 mm Hg. Therefore carbon dioxide diffuses through the RM from the blood in the lung capillary into the air in the alveolus where it is then expelled.

34. Discuss the factors that influence the rate at which a gas diffuses.

The factors that influence the rate at which a gas flows include: exchange surface area, diffusion distance, and breathing rate and depth.

35. Define the term internal respiration.

Internal respiration is the exchange of gases between the blood in the tissue capillaries and the tissue cells.

36. Discuss how oxygen and carbon dioxide are transported in the blood.

Oxygen is loosely carried by the hemoglobin in erythrocytes as oxyhemoglobin.

Most carbon dioxide (70%) is carried as bicarbonate ion; 23% is carried by hemoglobin as carbaminohemoglobin, and 7% is diffused in the blood.

37. Name the three factors that cause oxygen to be released from the hemoglobin

of red blood cells.

Oxygen is released by hemoglobin under the following conditions: increased temperature; increased carbon dioxide concentration/pressure; decreased blood pH.

38. Define the term hypoxia, and describe how it occurs during carbon monoxide

poisoning.

Hypoxia is a reduction of oxygen to cells. Because carbon monoxide is tightly bound to hemoglobin, there are fewer hemoglobin molecules to carry oxygen.

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39. Write the chemical equation that involves carbon dioxide, water, carbonic acid, a hydrogen ion, and a bicarbonate ion, and explain its significance.

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40. Locate the neural respiratory center on the diagram below.

Rhythmicity area is located in the medulla. It is composed of a dorsal respiratory group which controls the basic rhythm of breathing and a ventral respiratory group which controls forceful breathing. Pneumotaxic area is located in the pons and controls rate of breathing.

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41. Explain how respiration is affected by varying chemical (CO2 and O2) concentration in the blood.