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Chapter 23 The Respiratory System

What structures make up the respiratory system?
Nose, pharynx, larynx, trachea, bronchi, and lungs.
Structurally, how is the respiratory system classified?
1-the upper respiratory system, which includes the nose, nasal cavity, pharynx, and associated structures.
2-the lower respiratory system, which consists of the larynx, trachea, bronchi, and the lungs.
Functionally, how is the respiratory system classified?
1-the conducting zone
2-the respiratory zone
What is the conducting zone?
Consists of a series of interconnecting cavities and tubes both outside and within the lungs.
What is the respiratory zone?
Consists of tubes and tissues within the lungs where gas exchange occurs.
What structures are associated with the conducting zone and what is their purpose?
Nose, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles.Their function is to filter, warm, and moisten air and conduct it to the lungs.
What structures are associated with the respiratory zone and what is their purpose?
Includes the respiratory bronchioles, alveolar ducts, alveolar sacs, and alveolar. These structures are the main site of gas exchange between air and blood.
The frontal bone, nasal bones, and maxillae form the bony framework of the ___________.
external nose
The cartilaginous framework of the external nose consists of the ___________, the _________, and __________.
septal nasal cartilage, lateral nasal cartilage, and alar cartilage.
What are the two openings on the under surface of the of the external nose called?
external nares or nostrils
What are the three functions of the internal structures of the external nose?
1-warming, moistening, and filtering incoming air
2-detecting olfactory stimuli
3-modifying speech vibrations
What is the nasal cavity lined with?
muscle and mucous membrane
What are the two openings that are located in the posterior portion of the nasal cavity in which it communicates with the pharynx?
the internal nares or choanae
What are the two regions called in which the nasal cavity is divided?
1-respiratory region
2-olfactory region
Three shelves formed by projections of the superior, middle, and inferior are called _______.
nasal conchae
What are the three anatomical regions of the pharynx?
3-laryngopharynx or hypopharynx
What is the opening in the oropharynx called?
What is the structure that connects the laryngopharynx with the trachea?
the larynx
How many pieces of cartilage are in the wall of the larynx?
What are the 3 pieces of cartilage of the larynx that occur singly?
thyroid, epiglottis, and cricoid
What are the cartilages in the larynx that are found in pairs?
arytenoid, cuneiform, and corniculate
Of the paired cartilages in the larynx, which is the most important and why?
The arytenoid cartilages, because they influence changes in position and tension of the vocal folds.
What is the larynx cartilage that is also known as the Adam's Apple?
the thyroid cartilage
What is the epiglottis?
the large leaf shaped piece of elastic cartilage that is covered by epithelium.
What is the glottis?
Consists of a pair of folds of mucous membrane, the vocal folds (true vocal cords) in the larynx, and the rima glottis.
Which of the cartilages of the larynx is attached to the first ring of cartilage of the trachea by the cricotracheal ligament?
cricoid cartilage
What is the landmark site for making an emergency airway/tracheotomy?
cricoid cartilage
What type of joints do the arytenoid cartilages form with the cricoid cartilages?
synovial joints
What are the superior pair of mucous membrane folds of the larynx called?
ventricular folds or false vocal cords
What are the inferior pair of mucous membrane folds of the larynx called?
vocal folds or true vocal cords
What is the space between the ventricular folds called?
rima vestibuli
What are the three layers of the trachea wall?
3-hyaline cartilage
4-adventita (composed of areolar connective tissue)
What is the structure that is also known as the windpipe?
Where does the trachea divide into right and left primary bronchi?
At the superior border of the fifth thoracic vertebra, the T5.
What shape are the cartilage that provide semirigid support to maintain patency so that the trachea wall does not collapse inward?
they are solid C-shaped rings.
Which of the primary bronchus is wider, shorter, and more vertical?
the right primary bronchus.
What is the internal ridge which is found at the point in which the trachea divides?
the carina
What branches from the primary bronchi?
the secondary/lobar bronchi
What many lobes does the right and left lung have?
right-3 lobes
left-2 lobes
What are the smaller bronchi that branch from the secondary bronchi?
tertiary/segmental bronchi
What branches from the tertiary/segmental bronchi?
What structure signifies the end of the conduction zone?
terminal bronchioles
What is the double-layered membrane that surrounds each lung?
the pleural membrane
If someone has pleural effusion, what is wrong with them?
they have excess fluid that has accumulated in the pleural space, due to inflammation.
What is the hilum/hilus?
Found on the mediastinal surface of each lung, through which bronchi, pulmonary blood vessels, lymphatic vessels, and nerves enter and exit.
How much smaller is the left lung, as a result of the cardiac notch?
about 10 percent smaller
What is the segment of lung tissue that each tertiary bronchus supplies called?
bronchopulmonary segment
What is the specific structure that participates in gas exchange?
What is the cell type found in alveoli that are the main site of gas exchange?
type I alveolar cells
What alveolar cell type contains microvilli, are fewer in numbers, secretes alveolar fluid, and keeps the surface between the cells and air moist?
type II alveolar cells/septal cells
What are the small compartments found in each bronchopulmonary segment called?
What does each lubule of the bronchopulmonary segment contain, and what is it wrapped in?
It is wrapped in elastic connective tissue and contain a lymphatic vessel, an arteriole, a venule, and a branch from the terminal bronchiole.
What is the name of the fissure that can be found on both lungs, dividing them into lobes?
Oblique fissure
What is the name of the fissure that can only be found on the right lung?
the horizontal fissure
How many tertiary bronchi are in both lungs?
What are the 4 parts of the respiratory membrane?
1-alveolar wall
2-epithelial basement membrane
3-capillary basement membrane
4-capillary endothelium
What are the two arteries that supply blood to the lungs?
pulmonary and bronchial arteries
What are the only arteries in the body that carries deoxygenated blood?
pulmonary arteries
What is ventilation-perfusion coupling?
A unique feature of pulmonary blood vessels in which constriction is in response to localized hypoxia. Vasoconstriction in response to hypoxia diverts pulmonary blood from poorly ventilated areas of the lungs to well-ventilated regions. The perfusion (blood flow) to each area of the lungs matches the extent of ventilation (airflow) to the alveoli.
Name some examples of structures and secretions that help maintain patency.
Boney and cartilaginous frameworks of the nose, skeletal muscles of the pharynx, cartilages of the larynx, C-shaped rings of cartilage in the trachea and bronchi, smooth muscles in the bronchioles, and surfactant in alveoli.
Name some factors that compromise patency.
Crushing injuries to the bone and cartilage, deviated nasal septum, nasal polyps, inflammation of mucous membranes, spasms smooth muscle, and a deficiency of surfactant.
What are the three basic steps of respiration?
1-pulmonary ventilation/breathing
2-external/pulmonary respiration
3-internal/tissue respiration
What does pulmonary ventilation/ breathing involve?
inhalation (inflow) and exhalation (outflow) of air and involves the exchange of air between the atmosphere and the lungs.
What does external / pulmonary respiration involve?
the exchange of gases between the alveoli of the lungs and the blood in pulmonary capillaries across the respiratory membrane. In this process, pulmonary capillary gains 02 and loses CO2.
What does internal/tissue respiration involve?
the exchange of gases between blood in systemic capillaries and tissue cells, the blood loses O2 and gains CO2.
In pulmonary respiration, what makes it possible for air to flow between the atmosphere and the alveoli of the lungs?
Alternating pressure differences created by contraction and relaxation of respiratory muscles.
Air moves into the lungs when the air pressure inside the lungs is _______than the air pressure in the atmosphere.
Air moves out of the lungs when the air pressure inside the lungs is ________than the air pressure in the atmosphere.
What is the air pressure of the atmosphere at sea level?
760 mmHg
When is the air pressure inside the lungs equal to the air pressure of the atmosphere?
Just before each inhalation(breathing in).
How is a lower pressure (lower than atmospheric pressure) in the alveoli achieved to produce flow of air into the lungs?
Increasing the size of the lungs.
What is Boyle's law?
The inverse relationship between volume and pressure.
What are the main muscles of inhalation?
The diaphragm and external intercostals.
What happens to the diaphragm during normal quiet inhalation?
It contracts causing it to flatten, lowering its dome. This in turn increases the vertical diameter of the thoracic cavity.
What happens when the external intercostals contract during inhalation?
They elevate the ribs and as a result, there is an increase in the anteroposterior and lateral diameters of the chest cavity.
The diaphragm is responsible for ______% of the air the enters the lungs and the external intercostals is responsible for ______% during quiet breathing.
75, 25
During quiet inhalations, what is the pressure between the two pleural layers in the pleural cavity called and what is the pressure?
intrapleural (intrathoracic) pressure, it is always subatmospheric (lower than atmospheric pressure)
As the volume of the lungs increase, what is the pressure in the lungs called?
Alveolar (intrapulmonic) pressure
What are the accessory muscles of inhalation?
sternocleidomastoid muscles, the scalene muscles, and the pectoralis muscles.
Inhalation is said to be a/an ________process.
Exhalation is said to be a/an ________process.
What muscular contractions are involved in exhalation?
When does exhalation start?
When the inspiratory muscle relax.
What is the alveolar pressure in the lungs during exhalation?
762 mmHg
Besides air pressure differences, name three factors that affect the rate of air flow and ease pulmonary ventilation.
Surface tension of the alveolar fluid, compliance of the lungs, and airway resistance.
What is the substance made of phospholipids and lipoproteins that is present in alveolar fluid and reduces surface tension?
What is respiratory distress syndrome (RDS)?
A breathing disorder of premature newborns in which the alveoli do not remain open due to lack of surfactant.
What is compliance of the lungs?
This refers to how much effort is required to stretch the lungs and chest wall.
Describe high and low compliance.
high-the lungs and chest wall expand easily
low-the lungs and chest wall resist expansion
Airflow =
the pressure difference between the alveoli and the atmosphere / the resistance
What is eupnea?
the term for the normal pattern of quiet breathing.
What is costal breathing?
A pattern of shallow (chest) breathing that consists of an upward and outward movement of the chest due to contraction of the external intercostals.
What is diaphragmatic breathing?
A pattern of of deep (abdominal) breathing that consists of the outward movement of the abdomen due to the contraction and descent of the diaphragm.
What is tidal volume(V t)?
The volume of one breath
What is the minute volume (M V)?
The total volume of air inhaled and exhaled each minute-respiratory rate x tidal volume
The air that remains in conducting airways (about 30 percent) that does not undergo respiratory exchange is called what ?
anatomic (respiratory) dead space
What is alveolar ventilation rate?
The volume of air per minute that actually reaches the respiratory zone.
What is the average inspiratory reserve volume (additional inhaled air) in males and females?
3100 mL in males
1900 mL in females
What is the average expiratory reserve volume (additional exhaled air) in males and females?
1200 mL in males
700 mL in female
What is forced expiratory volume in one second (FEV 1.0)?
the volume of air that can be exhaled from the lungs in one second with maximal effort following a maximal inhalation.
What is the residual volume in males and females?
1200 mL in males
1100 mL in females
What is Dalton's law?
According to this law, each gas in a mixture of gases exerts its own pressure as if no other gases were present.
What is partial pressure(P x)?
The pressure of a specific gas in a mixture.
How is the total pressure of a gas calculated?
Simply by adding all the partial pressures.
Name some components in atmospheric air.
nitrogen (N 2), oxygen ( O 2), argon (Ar). carbon dioxide (CO 2), variable amounts of water vapor (H 2 O), plus other gases present in small quantities.
What is atmospheric pressure?
760 mmHg
What is exhaled air a mixture of?
alveolar air and inhaled air that was in the anatomic dead space.
What is Dalton's law?
Each gas in a mixture of gases exerts its own pressure as if no others gases were present.
The ________the difference in partial pressure, the ________the rate of diffusion.
greater, faster
What is Henry's law?
States that the quantity of a gas that will dissolve in a liquid is proportional to the partial pressure of the gas and its solubility.
Using Henry's law, describe why nitrogen in the air can have serious negative effects below sea level.
Scuba diver scenario, as the total air pressure increases, the partial pressures of all its gases increase. When a scuba diver breathes in air under high pressure, the nitrogen in the mixture can have serious negative effects. *the partial pressure of nitrogen is higher in a mixture of compressed air than in air at sea level.
What is external respiration/pulmonary gas exchange?
The diffusion of O 2 from air in the alveoli of the lungs to blood in pulmonary capillaries and the diffusion of CO 2 in the opposite direction.
What is internal respiration/systemic gas exchange?
The exchange of O 2 and CO 2 between systemic capillaries and tissue cells.
Name some factors that effect the rate of pulmonary and systemic gas exchange.
1-partial pressure differences of the gases
2-surface area available for gas exchange
3-diffusion distance
4-molecular weight and solubility of the gases
Oxygen and hemoglobin bind to an easily reversible reaction to form _____________.
What is the most important factor that determines how much O 2 binds to hemoglobin?
The P O 2; the higher the P O 2, the more O 2 combines with Hb.
Name four factors that affect the affinity of hemoglobin for O 2?
2-partial pressure of carbon dioxide
4-BPG, a substance found in RBC's
What are the three main forms in which carbon dioxide is transported in the blood?
1-dissolved CO 2
2-carboamino compounds
3-biocarbonite ions
What is hemoglobin that has bound to CO 2 called?
carbaminohemoglobin (Hb-CO 2)
What is the Haldane effect?
The lower the amount of oxyhemoglobin (Hb-O 2), the higher the CO 2 carrying capacity of the blood.
What three areas is the respiratory center divided into?
1-the medullary rhythmicity area in the medulla oblongata
2-the pneumotaxic area of the pons
3-the apneustic area, also in the pons