Learning Objectives for Chapter 22
THE RESPIRATORY SYSTEM
1. State the function of the respiratory system.
- Gas exchange: CO2 for O2
- Regulation of blood pH
- Smell receptors, filter air, produces vocal sounds, gives off water and heat.
2. Explain how the larynx directs the flow of air and food into their proper channels:
When food is swallowed, both larynx and pharynx rise. This enables pharynx to widen and pass the food down. When larynx rises, the epiglottis closes the glottis and directs the food to go down the esophagus.
2. State the function of the cough reflex:
To dislodge and expel possible foreign object in the larynx, trachea, or epiglottis.
2.State the functions of mucus and cilia in the respiratory epithelium.
Mucus and cilia lining the larynx, are also called the mucociliary escalator, because they catch dust and debris in the respiratory tract and move it up where it can be swallowed and broken down in the stomach.
3. Describe how sounds are produced.
Sound originates from air directed against the vocal folds which cause them to vibrate and produce sounds (phonation). Sound is converted to recognizable speech by using the pharynx, mouth, nasal cavity, and paranasal sinuses as resonating chambers.
4. Define laryngitis:
Inflammation of the larynx.
5. Explain the functions of both the open and C-shaped portions of the tracheal cartilage rings.
Provides a semirigid support so that the tracheal wall does not collapse inward and obstruct the passageway during inspiration.
6. Summarize the lungs by stating: The source and functions of pleural fluid
- Source: secreted by the visceral and parietal pleurae.
- Function: reduces friction (lubricates) between the two membranes during movement caused by respiration.
6. Summarize the lungs by stating: The number of lobes in each lung
- Left: 2 Lobes; Superior Lobe and Inferior Lobe.
- Right: 3 Lobes; Superior, Middle & Inferior Lobes.
6. Summarize the lungs by stating: Why it is surgically significant that each bronchopulmonary segment has its own bronchus and blood supply
It is surgically significant that each bronchopulmonary segment has its own bronchus and blood supply so that Bronchial and pulmonary disorders such as tumors or abscesses that are localized in a bronchopulmonary segment may be surgically removed without seriously disrupting the surrounding lung tissue.
7. Describe the sequence of structures an air molecule encounters from the time it is inhaled until it reaches an alveolus.
- External nares
- Nasal cavity
- Pharynx (Nasopharynx, Oropharynx, Laryngopharynx)
- Primary bronchi
- Secondary (Lobar) bronchi
- Tertiary bronchi (Segmental)
- Terminal bronchioles
- Respiratory bronchioles
- Alveolar ducts
- Alveolar sac
8.Describe pneumothorax, atelectasis, and the relationship between them.
- Pneumothorax: occurs when there is free air in the pleural cavity.
- Atelectasis: is a collapsed lobe, or entire lung.
9.Do read about lung cancer and tuberculosis, as they are important to your health and career although the exam will not ask about them.
10. Define the abdominal thrust (Heimlich) maneuver.
a technique used to eject an object (such as food) from the trachea of a choking person; it employs a firm upward thrust just below the rib cage to force air from the lungs.
11. Describe alveoli by: Explaining why their structure allows sufficient gas diffusion to sustain life: alveolar wall is thin, consists of simple squamous epithelium and a thin basement membrane, allowing gas diffusion. Additionally, the numerous alveolar sacs increase the surface area.
11. Describe alveoli by: Stating the function of alveolar macrophages:
dispose of debris, fine dust particles and pathogens by phagocytosis.
11. Describe alveoli by: Describing the structure of the respiratory membrane:
- Is the diffusion site for CO2/O2. Is composed of four layers:
- 1. Type I and Type II alveolar cells
- 2. epithelial basement membrane
- 3. capillary basement membrane
- 4. capillary endothelium
12. Summarize gas exchange in the body by: Describing the three basic steps of respiration:
- 1. Breathing (pulmonary ventilation)- exchange of air in atmosphere and alveoli in lungs
- 2. External respiration- exchange of gasses in alveoli in lungs and blood in pulmonary capillaries. (capillary blood gains O2 and looses CO2)
- 3. Internal respiration- exchange of gases between blood in systemic capillaries and tissue cells. (blood loses O2 and gains CO2)
12. Summarize gas exchange in the body by: Stating the common name for pulmonary ventilation:
12. Summarize gas exchange in the body by: Differentiating between internal respiration and cellular respiration:
The exchange of gases between systemic capillaries and tissue cells while cellular respiration includes the use of O2 for metabolic reactions during ATP production and the generation of CO2.
13. Summarize pulmonary ventilation including: The other name for inhalation
13. Summarize pulmonary ventilation including: How changes in the volume occupied by a gas result in changes in the pressure of that gas:
KISS: The pressure of a gas increases as the volume occupied decreases. Memory trick: 5 people in a Hummer vs 5 people in a MINI Cooper (or any compact sized car).
13. Summarize pulmonary ventilation including: Pressure changes in the thoracic cavity during pulmonary ventilation:
- Inhalation: Thoracic cavity volume increases causing lung volume to increase in size causing alveolar pressure (762 mmHg) to go below atmospheric pressure (760 mmHg) this pushes air into our lungs.
- Exhalation: Thoracic cavity volume decreases (758 mmHg) due to elastic recoil; as exhaling lungs resume a smaller volume alveolar pressure rises above atmospheric pressure which drives air out of the lungs.
13. Summarize pulmonary ventilation including: Intrapleural pressure and its involvement in the lungs being pulled outward as the thoracic cavity expands:
As the thoracic cavity expands pleural fluid acts as an adhesive pulling the lungs to expansion with the thoracic walls. The pressure inside the lungs become less than the pressure outside the body, (air is pushed into the lungs going from the area of greater pressure to the area of lesser pressure).
13. Summarize pulmonary ventilation including: The other name for exhalation:
13. Summarize pulmonary ventilation including: How inhalation and exhalation occur during both normal quiet and forceful ventilation including muscle actions (the exam will not ask the names of the accessory muscles of forceful ventilation), volume changes in the thorax, elastic recoil, and pressure changes
- Inhalation: Thoracic cavity volume increases causing lung volume to increase in size, alveolar pressure goes below atmospheric pressure, this pushes air into our lungs. When the pressure inside the lungs become less than the pressure outside the body air is pushed into the lungs going from the area of greater pressure to the area of lesser pressure.
- Exhalation: Thoracic cavity volume decreases due to elastic recoil. When the pressure inside the lungs is greater than the pressure outside the body air is pushed out of the lungs going from the area of greater pressure to the area of lesser pressure.
13. Elastic Recoil is a result of:
- 1. a high number of elastic fibers between alveoli that make the lungs snap back to a smaller size after inhalation like a stretched rubber band springs back to its original size, and
- 2. alveolar fluid surface tension that constantly draws alveoli to their smallest possible dimension.
13. Summarize pulmonary ventilation including: The role of surfactant in pulmonary ventilation [also see Alveoli discussion in your textbook]
- Surfactant, a fluid composed of phospholipids and lipoproteins that coats alveolar cells, reduces alveolar surface tension and prevents alveolar collapse during exhalation.
- More, non-KISS information: Surface tension exists at all liquid-gas interfaces and is a result of water molecules' greater attraction for other water molecules than for air molecules. So in a case where liquid surrounds a gas, such as in a soap bubble, the surface tension force is a force pulling the outer water molecules inward into the bubble's sphere toward the water molecules on the other side, essentially trying to burst the bubble or collapse it inwards. The layer of surfactant covering alveoli have a surface tension less than pure water and so there is less inward "bursting" force to collapse the alveoli.
14. Define emphysema. Do read about asthma, as it is important to your health and career even though the exam will not ask about it.
A lung disorder in which alveolar walls disintegrate, producing abnormally large air spaces and loss of elasticity in the lungs; typically caused by exposure to cigarette smoke
14. Define respiratory distress syndrome.
- A deficiency of surfactant in premature infants in which the surface tension of alveolar fluid is greatly increased, so that many alveoli collapse at the end of each exhalation. (Great effor tis then needed at the next inhalation to reopen the collapsed alveoli.
- 15. Describe hiccupping.
- Hiccupping is spasmodic contraction of the diaphragm followed by closing of the glottis thus producing a sound on inhalation.(Caused by irritation of the sensory nerve endings of the GI tract).
15. Describe the Valsalva maneuver.
forcibly exhaling while keeping the glottis closed (keeping the nose and mouth closed) as one would do while straining during a bowel movement or bearing down or blowing a stuffy nose.
16. Describe partial pressure:
The pressure exerted by a single component of a mixture of gases
16. State how the movement of a gas into a liquid is influenced by its partial pressure:
gas can move when the partial pressure is higher than liquid, that way the gas can dissolve into the liquid and be transported
16. Explain why inhaled air has a different composition than alveolar air.
- 1. External respiration (pCO2 is greater in the alveolar air than in the atmosphere due to CO2 production in the tissue cells, carried to the lungs via veins
- 2. As the inhaled air passes though the upper respiratory tract, it is humidified and the water vapor content of the air increases and relative O2 decreases.
- 3. Exhaled air contains more O2 than alveolar air due to the anatomic dead space air that didn't participate in the gas exchange
17. Describe gas diffusion during: External Respiration:
The diffusion of O2 from air in the alveoli of the lungs to blood in pulmonary capillaries and the diffusion of CO2 in the opposite direction.
17. Describe gas diffusion during: Internal Respiration:
The exchange of O2 and CO2 between systemic capillaries and tissue cells. Occurs in tissues throughout the body.
18. Describe gas transport by: Stating how most oxygen is transported in blood:
Most of the oxygen (98.5%) is transported in blood bound to hemoglobin in red blood cells.
18. Describe gas transport by: Describing the mechanisms for transporting carbon dioxide in blood
- 1. Dissolved CO2
- 2. Bound to hemoglobin (globin chain)=carbaaminohemoglobin
- 3. Bicarbonate ions
18. Describe gas transport by: Summarizing how bicarbonate ions form in blood
- When CO2 diffuses into systemic capillaries and goes into the blood cells - this is how 70% of CO2 is transported in blood plasma.
- Carbonic Anhydrase is the enzyme which catalyzes the conversion of CO2 and water into bicarbonate and protons.
- CO2 + H2O <--> HCO3- + H+ (Rapid, reversible reaction)
19. Briefly describe the physiology of carbon monoxide poisoning:
The carbon monoxide molecule is more attractive to O2 molecules than the heme binding site due to polarity, therefore O2 is lost to form CO2 leaving less O2 available to red blood cells.
19. Briefly describe the physiology of the effect of smoking on respiratory efficiency:
- 1. less airflow in and out of lungs to constricted brachioles
- 2. CO causes reduction in O2 in blood
- 3. increase mucosa, mucosal lining swelling, less airflow of lungs
- 4. inhibit cilia and destroy cilia lining - mucus and foreign debris are easily trapped.
- 5. destruction of elastic fiber in lungs --> possible destruction of walls of the alveoli
- summing it up- restricted air flow in and out of lungs
20. Summarize the control of respiration by: Stating the brain region that contains the inspiratory and expiratory areas:
Medullary rhythmicity area( of the respiratory center in the medulla oblongata of the brain)
20. Summarize the control of respiration by: Explaining how inspiratory areas regulate ventilation:
Inspiratory Area: Sends nerve impulses to the diaphragm via the phrenic nerve and external intercostal muscles via the intercostal nerves, causing contraction of the muscles. Contraction of the diaphragm and external intercostals causes inspiration via increasing thoracic cavity volume.
20. Summarize the control of respiration by: Explaining how expiratory areas regulate ventilation:
Expiratory Area: Activated by nerve impulses from the inspiratory area during forceful exhalation. Sends nerve impulses to the internal intercostal muscles and abdominal muscles. Contraction of the internal intercostal and abdominal muscles cause exhalation via decreasing thoracic cavity volume.
20. Summarize the control of normal respiration:
During normal, non-forceful breathing, the expiratory area is not activated. Normal expiration occurs when the inspiratory area stops innervating the diaphragm and external intercostals and they relax.
20. Summarize the control of respiration by: Describing how the pons respiratory centers influence ventilation.
- Upper pons (pneumotaxic area)- transmits inhibitory impulses to respiratory area, the effect of the impulses is to shorten the duration of inhalation so lungs don't get too full.
- Lower pons (apneustic area)- sends stimulating impulses to respiratory area that result in long deep inhalation.
21. Define hypoxia:
Insufficient oxygen at the tissue level.
22. Explain how the rhythm of respiration can be modified by: Describing our ability to voluntarily control respiration via the cerebral cortex:
Cerebral cortex have connections with the respiratory center, we can voluntarily alter our pattern of breathing, we can even refuse to breath at all for a short while to protect ourselves from inhalation of toxic gases or liquids. The ability to suspend breathing is limited by the build up of carbon dioxide and hydrogen ions in the body. When Pco2 and H+ concentration increase to a certain level the inpiratory area is strongly timulated, nerve impulses are sent along the phrenic and intercostal nerves to inspiratory muscles, and breathing resumes.
22. Explain how the rhythm of respiration can be modified by: Summarizing how carbon dioxide and oxygen levels regulate ventilation and blood pH:
- Increasing the rate and depth of breathing - more CO2 is exhaled (less in the body) > causes carbonic acid in blood to decrease and raises the blood pH. Ventilation is slower > less CO2 (more in the body) > blood pH lowers
- Increased Carbon Dioxide Levels: Raises blood pH and stimulates increased respiratory rate.
- Increased Oxygen Levels: Lower blood pH and stimulates a decrease in respiratory rate.
22. Explain how the rhythm of respiration can be modified by: Stating how emotions, pain, and airway irritants influence respiration
Emotions such as crying or laughing usually cause an inhalation followed by multiple short convulsive exhalations. Pain can cause a contraction of muscles followed by a prolonged exhalation. Finally, when there are airway irritants present, it may cause one to sneeze or cough. For a cough, there is a long and deep inhalation followed by a strong exhalation through the respiratory passages to expel any blockage or irritant. For a sneeze, there is a spasmodic contraction of muscles of exhalation that expels air through the nose and mouth.
Explaining how the carbonic acid-bicarbonate buffer system helps regulate blood pH:
- KISS: Low blood pH (excess H cations) --> HCO3 anions + H cations = H2CO3(carbonic acid) --> dissociation of H2CO3=H2O + CO2 --> CO2
- exhaled by lungs. High blood pH (deficit of H cations) ---> H2CO3 dissociates = HCO3 anions + H cations ---> neutralizing the excess.
23. Summarize how the respiratory system helps maintain acid-base balance by: Explaining how the carbonic acid-bicarbonate buffer system helps regulate blood pH:
- Carbonic acid-bicarbonate buffer system utilizes bicarbonate ion (HCO3 negative ) as a weak base and carbonic acid (H2CO3) as a weak acid to maintain pH of blood (normal pH is between 7.35-7.45) and thus maintain homeostasis.Bicarbonate negative ion is an important component of both intracellular and extracellular fluids and blood. End product of cellular respiration produces carbon-dioxide(CO2) constantly which combines with water(H2O) and forms carbonic acid. This has the capability of dissociating into water and carbondioxide and/or hydrogen cations and bicarbonate anions.
- If the pH of blood is low (higher level of H+ ions), bicarbonate ion combines with the excess H+ ions and forms carbonic acid which dissociates into H2O and CO2.Respiratory system exhales CO2 out through lungs.
- If the pH is high ( deficit of H+ ions) carbonic acid dissociates into H+ ions and HCO3 negative ions thus providing the H+ ions.
23. Summarize how the respiratory system helps maintain acid-base balance by: Explaining how changes in the rate and depth of breathing can alter the pH of body fluids
By Increasing the rate and and depth of breathing, more carbon dioxide can be exhaled, within minutes this reduces the level of carbonic acid in blood, which rises the PH(reduces Hydrogen level) An increase in carbon dioxide concentration in body fluids increses hydrogen concentration and thus lowers the ph (body fluids more acidic) decrease in carbon dioxide concentration of the body fluids raises the ph (body fluids more alkaline)
23. Summarize how the respiratory system helps maintain acid-base balance by: Describing acidosis and alkalosis
Acidosis occurs when the blood pH is below 7.35, so the blood is too acidic. This causes depression of the nervous system. Alkalosis occurs when the blood pH is above 7.35, so the blood is too basic. This causes over-excitability of the nervous system.
24. Identify and state the functions (unless marked *) of the following: Nose, Nasal cavity, nasal Conchae and Internal naris:
- External naris (plural = nares)-outer opening of the nose where aier goes through in the nose.
- Nasal cavity - space within the internal nose and is lined with mucous membrane and helps receive air
- Nasal conchae
- Internal naris-Traps dust and foreign particle and detecting smell.
(throat) is a tube passageway for air and food and provides resonating chamber for speech and sounds.
Receives air from the nasalcavity along with the dust-laden mucus. also exchange of small amount of air with the auditory tubes to equalize air pressure between the pharynx and the middle ear
Its a common passage way for air,food and drink.(respiratory and digestive fuction)
Has both respiratory and digestive pathway and is lined by nonkeratinised stratified squamous epithium.
Larynx: (voice box) a short passageway which connects laryngopharynx with the trachea
Helps to attach hyoid bone and epiglottis and inferiorly connects cricoid cartilage.
Moves to covers the larynx and airways during swallowing which routes food and liquids into the esophagus and not into the windpipe.
24. Cricoid Cartilage:
ring of supportive hyaline cartilage inferior to the Thyroid cartilage, but superior to the trachea.
24. Vocal Folds:
Vocal folds (vocal cords)-origin of sound production during speaking and singing.
Consists of the vocal cords and the space between. Helps in forming a lid with Epiglottis
24. Identify and state the functions (unless marked *) of the following: Trachea & Tracheal Cartilage:
- Trachea: Provides an air passageway from the larynx to the bronchi. Also, contains a mucous membrane to protect from dust.
- Tracheal cartilage: is the structural support for the trachea which prevents collapse of it's walls. Located above the cricoid cartilage.
24. Primary, Secondary & Tertiary Bronchus:
- Primary bronchus (plural = bronchi): Trachea splits at Carina to form Right & Left Primary Bronchi.
- Secondary (lobar) bronchus: Left/Right primary branches into Secondary Bronchi.
- Tertiary (segmental) bronchus: Branchings of Secondary Bronchi.
24. Bronchiole & Alveolus:
- Bronchiole: tertiary bronchi divide to form bronchioles, which in turn branch into terminal bronchioles.
- Alveolus (plural = alveoli): cup shaped outpouching lined by simple squamous epithelium. Exchange of O2 & CO2 by diffusion occurs between Alveoli and capillary walls.
24. Lung, Parietal Pleura & Visceral Pleura:
- Lungs: paired organs separated form each other by the mediastinum.
- Parietal pleura: Lines the wall of the thoracic cavity to protect to lung.
- Visceral pleura: cover each lung.
24. Cardiac notch:
Located at about the 5th and 6th intercostal spaces, it is an indentation of the left lung caused by the heart pushing into the left lung. Pericardiocentesis (aspirating fluid from the pericardium) can be performed immediately right of the notch so the lung is not pierced.
- Left: Superior and Inferior Lobe.
- Right: Superior, Middle, and Inferior Lobe.
- 24. Identify and state the functions (unless marked *) of the following: Diaphragm
- skeletal muscle that is dome-shaped that partition the abdominal cavities and
- thoracic cavities
24. External intercostals:
Contraction of the external intercostal muscles aids the diaphragm in inspiration.