Ch 21 Review Questions for Anatomy and Physiology PDF

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Ch 21 Review Questions for Anatomy and Physiology for the second exam of the semester, it covers in detail what the preffesor of the course is wanting....

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1. The _________ zone includes the alveoli, while the _______ zone includes the trachea. A) Conducting; respiratory B) Transport; ventilation C) Respiratory; conducting* D) Ventilation; transport 2. Breathing air through the nose provides multiple functions. What function would be most impacted while breathing dry air? A) Warming of the air B) Delivering the air to the lungs C)Providing a resonance chamber for speech D)Humidifying the air***** 3. Surface area in the nasal cavity is increased by the presence of projections called ___conchae(turbinate bones)________ and the groves between them called __nasal meatuses___(superioir,middle, inferioir)___. 4. Red blood cells contain the enzyme __ carbonic anhydrase________, which catalyzes the formation of carbonic acid. 5. Explain the three factors that affect the affinity of hemoglobin to oxygen. (1) the temperature, (2) the pH of the blood, and (3) the PCO2 ** The opposite is also true—as the temperature, acidity, and PCO2 decrease, as occurs in tissues with a slower metabolic rate, Hb binds oxygen more strongly, and less oxygen is unloaded. This phenomenon is known as the Bohr effect.

6. Hemoglobin molecules are fully saturated when bound to _____4 OXYGEN_____ molecule(s) of O2. 7. Why is the rate of CO2 exchange roughly equivalent to that of O2 despite its less steep pressure gradient? A) CO2 diffuses much more rapidly out of the cells. B) CO2 binds to O2 and moves across the respiratory membrane simultaneously. C) CO2 is more soluble in water than is O2. D) CO2 is actively transported into the alveoli. 8. Even the most forceful exhalation leaves air in the lungs; this is called the ____residual volume_______ and is needed to ___keep alveoli patent ________.

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9. The typical volume of air involved in alveolar ventilation is __350_____ ml.

10. Air moves into the lungs during inspiration due to the force of _______. A) The diaphragm B) The abdominal muscles C) Atmospheric pressure D) The external intercostal muscles 11. Men tend to have deeper voices than women because their vocal cords ___________. A) Are thick and long and vibrate slower B) Deliver the air to the lungs C) Provide a resonance chamber for speech D) Humidify the air 12. Occasionally food or liquids will “go down the wrong pipe,” initiating a cough reflex. Which structural barrier has been breached if this happens? Epiglottis 13. Which one is NOT a larynx cartilage? A) Thyroid cartilage B) Arytenoid cartilage C) Septal cartilage D) Cuneiform cartilage

14. Explain the changes in the atmospheric and intrapulmonary air pressure, muscle contraction, lungs and thoracic cavity during inspiration and expiration.

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15. What are the factors that affect lungs compliance?

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Degree of alveolar surface tension. As you just learned, surface tension on the alveoli resists their inflation, but surfactant counters this tension. Distensibility of elastic tissue in the lungs. The elastic tissue in the lungs gives them not only their ability to recoil but also the ability to stretch during inflation. Ability of the chest wall to move. The chest wall must also stretch during inspiration, as the lungs and chest wall move together. 16. (1)What is the relationship between air resistance and the diameter of air ways? (2)How is the diameter of the air ways are controlled?(3) Define bronchodilation and bronchoconstriction.

1. The first physical factor, airway resistance, is anything that impedes airflow through the respiratory tract; it is similar to blood vessel resistance. As in blood vessels, the degree of resistance in the airways is largely determined by the diameter of the passageway. Resistance normally varies during pulmonary ventilation due to changes in intrapulmonary pressure. During inspiration, resistance decreases slightly because the airways are pulled open as the lungs expand, and during expiration, resistance increases slightly as the lungs recoil and the airways narrow. These normal changes in resistance do not adversely affect pulmonary ventilation due to the large diameter of the bronchi and supporting cartilage, as well as the huge total cross-sectional area of the bronchioles. 2. controlled by the contraction or relaxation of the smooth muscles of the bronchioles 3. Relaxation of the bronchial smooth muscle, or bronchodilation, increases the diameter of the bronchioles. Figure 21.16 shows that this increases the size of the bronchiole’s lumen, which decreases airway resistance. when the smooth muscle contracts, a process called bronchoconstriction, the diameter of the bronchioles can decrease dramatically this narrows the lumen of the bronchiole, which dramatically increases resistance.

17. What are the three transport mechanisms of CO2? Which one is the main mechanism? 5

Dissolved in the plasma. Recall from our earlier discussion that carbon dioxide has a higher solubility in water than does oxygen. For this reason, more carbon dioxide than oxygen dissolves in plasma, and about 7– 10% of the total carbon dioxide is transported in this manner. Bound to Hb within erythrocytes. About 20% of carbon dioxide is transported by Hb. Unlike oxygen, carbon dioxide doesn’t bind to the heme group of Hb. Instead, carbon dioxide binds to Hb’s polypeptide chains. Carbon dioxide binds easily and reversibly with Hb, forming carbaminohemoglobin (not to be confused with carboxyhemoglobin, which is the combination of carbon monoxide with Hb). As bicarbonate ions in blood. The majority of carbon dioxide in the blood (about 70%) travels as a totally different compound, bicarbonate ion (HCO ). − 3

18. Explain how bicarbonate buffer system adjust blood pH? One of the primary buffer systems in the body is the carbonic acid– bicarbonate buffer system (Under normal conditions, the pH of the blood changes very little from its normal 7.35–7.45 range when hydrogen ions are added. The change is small because the hydrogen ions bind with buffers such as bicarbonate ions (HCO ) to form carbonic acid (H CO ). The opposite reaction also takes place—when the blood pH increases and the level of hydrogen ions drops too low, hydrogen ions are released from carbonic acid to bring the pH back down to the normal range. − 3

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19. The increase of hydrogen ions concentration __acid_________ the pH while a decrease in hydrogen ions concentration________ alkaline_____ the pH. 20. The posterior opening of nasal cavity is called _____posterior nares and vestibule______.

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21. What is the epithelial tissue covering the following section of the respiratory tract? Nasal cavity: The paranasal sinuses and nasal cavity have a continuous epithelium; vestibule is lined with stratified squamous, the epithelium changes to become two types of mucous membrane: the olfactory mucosa ( located on the roof of the nasal cavity; bipolar neurons) and the respiratory mucosa.( pseudostratified ciliated columnar with globet cells) Nasopharynx: pseudostratified ciliated columnar epithelium; the two structures therefore perform the same functions of warming, humidifying, and filtering the inspired air. Oropharynx: nonkeratinized stratified squamous epithelium Laryngopharynx: nonkeratinized stratified squamous epithelium Larynx (above vs below vocal cords): Above- stratified squamous nonkeratinized epithelium that is continuous with that of the laryngopharynx Below- pseudostratified ciliated columnar epithelium Bronchioles: thicker ring of smooth muscle and simple cuboidal epithelium with few cilia and few, if any, goblet cells. This is because most dust and debris have been removed by the time the air reaches the bronchioles. Alveoli: Type 1- simple squamous Type 2- cuboidal

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22. Where is carina located? The last tracheal cartilage ring is called the carina

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23. How many primary, secondary (lobar) and tertiary (segmentary) bronchi exist in each lung? ( due to the space needed for the heart) Left : Primary - narrower, longer, and more horizontal Secondary - only two Tertiary - 10 tertiary bronchi can be found in each lung, although the left lung may have one or two fewer than the right lung. Right : Primary - wider, shorter, and straighter Secondary - three secondary bronchi Tertiary - 10 tertiary bronchi can be found in each lung

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24. What is the last portion of conducting zone called? Describe its characteristics. Terminal Bronchioles The smallest airways of the bronchial tree are its tiny bronchioles By definition, bronchioles are less than 1 mm in diameter and lack cartilage. Bronchioles also feature a thicker ring of smooth muscle and simple cuboidal epithelium with few cilia and few, if any, goblet cells. This is because most dust and debris have been removed by the time the air reaches the bronchioles. Bronchioles continue to branch until they become tiny terminal bronchioles, which are the final part of the conducting airways. To give you a sense of perspective, your lungs contain about 65,000 terminal bronchioles.

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25. Name three sections of respiratory zone? Respiratory Bronchioles Alveolar ducts Alveolar sacs

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26. What is the relationship between blood oxygen pressure and hemoglobin affinity for oxygen?  the tightness with which Hb binds oxygen, also called the affinity, or the bond strength, of Hb. It is a positive relationship: at pressure increases, hemoglobin has a higher affinity or oxygen so more oxyhemoglobin is present. And when partial pressure of oxygen decreases, then hemoglobin has a lower affinity for oxygen and gives up more of it

27. Why does hemoglobin have high affinity for oxygen in arterial blood and lower affinity in capillary beds? Explain in terms of blood oxygen pressure?

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Steps for oxygen to tissues:

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1. Oxygen solubility in water is rather low, so it cannot easily dissolve in plasma. As a result, only about 1.5% of the oxygen picked up by the blood in the lungs is dissolved in plasma. The remaining 98.5% enters erythrocytes and is transported in blood bound to the protein hemoglobin.

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2. There are about 280 million hemoglobin molecules inside erythrocyte, each hemoglobin consists of four polypeptides. Each polypeptide contains a heme group with an iron in the center, which is capable of binding to one oxygen molecule. Each

hemoglobin can carry up to four oxygen molecules. The binding of oxygen to hemoglobin is a reversible reaction; oxygen needs first to be loaded onto hemoglobin in the lungs and then unloaded in the tissues.

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3. In the lungs, oxygen from the alveoli binds to hemoglobin inside erythrocytes in the pulmonary capillaries. Hemoglobin bound to oxygen is called oxyhemoglobin. Such hemoglobin can be partially saturated, carrying fewer than four oxygen molecules or fully saturated, carrying a full load of four oxygen molecules. At a partial pressure of oxygen of about 100 mm Hg, which is what we find in the lungs, all hemoglobin molecules are fully 100% saturated.

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4. During unloading in the tissues, hemoglobin releases oxygen to the tissue cells. The amount of oxygen unloaded must strictly match the metabolic needs of the tissues. Once the partial pressure of oxygen drops below 100 mm Hg, hemoglobin unloads some of its oxygen cargo. At a tissue oxygen partial pressure of about 40 mm Hg, hemoglobin saturation is 75% which means that 75% of the hemoglobin’s heme groups are bound to oxygen and 25% of the heme groups have released their oxygen to the tissues. Metabolically active tissues use more oxygen, therefore tissues oxygen partial pressure might drop below 40. As a result, more oxygen will be unloaded from hemoglobin to theses tissues.

28. What is the oxygen pressure in alveoli, arterial blood and tissue? What is the direction of oxygen diffusion in lungs and tissue? Oxygen pressure: Alveoli-100mm Hg Arterial blood -100mm Hg Tissues-40-20 mm Hg Gas Exchange in the lungs  Each alveoli s surrounded by capillaries, oxygen diffuses from the alveolus to the blood, and carbon dioxide diffuses from the blood to the alveolus. As blood flows through the capillary it becomes rich in oxygen. Transporting Oxygen  In the blood oxygen diffuses into red blood cell and binds to hemoglobin a protein made up of four subunits. One oxygen molecule can bind to each subunit. Oxygen rich blood flows from the lungs to the heart, which pumps this blood to capillaries all over the body. Gas exchange in body tissues  Here we see oxygen diffusing from a capillary’s red blood cells into a muscle cell. Oxygen is used by the cells mitochondria to produce ATP during cellular respiration. Carbon dioxide is released. Transporting Carbon Dioxide  Carbon dioxide diffuses from cells into capillaries. Some carbon dioxide stays in the plasma, the liquid part of the blood. most carbon dioxide however enters red blood cells. Some carbon dioxide binds to hemoglobin the rest is converted to 14

bicarbonate which diffuses into the plasma. This oxygen poor blood flows back to the heart, which pumps it to the lungs, there carbon dioxide diffuses from the plasma into the alveoli. Bicarbonate enters red blood cells and is converted back to carbon dioxide which is also released from hemoglobin. Carbon dioxide diffuses out of the red blood cells into the plasma into the and into the alveolus. when you exhale air flows out of your lungs. 29. Name the conditions that can increase intrapleural pressure and can result in lungs collapse. What happens if the intrapleural pressure increases to a level at or above atmospheric pressure? Under these conditions, the intrapleural pressure no longer exerts a suction effect that prevents the lungs from collapsing. Indeed, the added pressure actually enhances the lungs’ elastic recoil, and the lungs immediately collapse, as shown here:

When the lung is fully collapsed, intrapulmonary pressure is so high that the body is unable to bring it below atmospheric pressure, and inspiration cannot occur. Many things can increase intrapleural pressure above atmospheric, including excess pleural fluid (a pleural effusion), air in the pleural cavity or blood in the pleural cavity (a hemothorax). The preceding illustration shows a pneumothorax caused by the trauma of a knife wound, but note that trauma is only one potential cause of lung collapse.

30. Define hypoxemia and hypercapnia. 15

We have already discussed the extremely large surface area of the respiratory membrane in Module 21.2. Recall that for the average person, it is about 80–100 m for both lungs (roughly 1000 square feet). Consider for a moment that only about 75–100 ml of blood is in the pulmonary capillaries at any given time—about the volume of a small coffee mug. The huge surface area of the respiratory membrane is enough for essentially every erythrocyte in this volume of blood to be in contact with the respiratory surface. Any factor that decreases the surface area of the respiratory membrane decreases the efficiency of pulmonary gas exchange. For example, the disease emphysema (em-fih-SEE-mah) causes destruction of the alveolar walls, which reduces the surface area of the respiratory membrane to as little as one-fifth of normal. This reduction results in severely impaired pulmonary gas exchange, leading to the conditions hypoxemia (hy′-pawk-SEE-mee-uh; a low level of oxygen in the blood) and hypercapnia (hy′- pur-KAP-nee-uh; a high level of carbon dioxide in the blood). 2

31. Explain respiratory alkalosis and acidosis. How are they related to hyperventilation and hypoventilation?

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