Ch. 23 Respiratory System Flashcards
Body cells must obtain ____ and eliminate ____
Obtain oxygen
Eliminate CO2
What are the 5 functions of the respiratory system?
- Provide an area for gas exchange between air and circulating blood
- Move air to and from exchange surfaces
- Protect respiratory surfaces from environmental variations and defend the respiratory system and other tissues from invasion by pathogens
- Produce sounds
- Facilitate the detection of olfactory stimuli
What are the divisions of the respiratory system?
Upper and lower
What does the upper respiratory system contain?
Nose, nasal cavity, paranasal sinuses, pharynx
What does the lower respiratory system contain?
Larynx, trachea, bronchi, bronchioles, alveoli
What does the respiratory tract consist of?
The conducting airways that carry air to and from the alveoli
What do the passageways of the upper respiratory tract do?
Filter and humidify incoming air
What is the respiratory mucosa?
The respiratory epithelium and underlying connective tissues
What does the respiratory mucosa line?
The conducting portion of the respiratory tract
What is the respiratory epithelium supported by?
The lamina propria
What is the lamina propria?
A layer of areolar tissue
What is the respiratory defense system made up of?
Mucus and cilia
What prevents contamination of the respiratory system?
Mucus and cilia
Where does air enter the respiratory system normally?
Through the nostrils
What do the nostrils open into?
The nasal cavity
What is the nasal vestibule guarded by?
Hairs that screen out large particles
Where does incoming air flow through?
Superior, middle, and inferior meatuses (narrow grooves) and then bounces off the conchal surfaces
What separates the oral and nasal cavities?
The hard palate
What does the soft palate separate?
The superior nasopharynx from the rest of the pharynx
What does the choanae connect?
The nasal cavity and nasopharynx
What does the nasal mucosa do?
Trap particles, warms and humidifies incoming air, and dehumidifies and absorbs heat of outgoing air
What is the pharynx?
Also called the throat
A chamber shared by the digestive and respiratory systems
What is the nasopharynx?
The superior part of the pharynx
What is the oropharynx continuous with?
The oral cavity
What does the laryngopharynx include?
The narrow zone between the hyoid bone and the entrance to the esophagus
Inhaled air passes through the ____ on the way to the ____
Glottis
Lungs
What surrounds and protects the glottis?
The larynx
What is the glottis?
The vocal apparatus
What 3 large cartilages and 3 small cartilages composes the cylindrical larynx?
Large cartilages:
Median thyroid cartilage
Median cricoid cartilage
Epiglottis
Small cartilages:
Arytenoid
Corniculate
Cuneiform
A pair of inelastic _____ surrounds the glottis
Vestibular folds
What does the glottis include?
The elastic vocal folds and the space between them, the rima glottidis
What does air passing through the open glottis do?
Vibrates its vocal folds, producing sound
What does the pitch of sound depend on?
The diameter, length, and tension of the vocal cords
What do the muscles of the neck and pharynx do for the larynx?
Position and stabilize it
What do the intrinsic muscles do for the larynx?
Regulate tension in the vocal folds or open and close the glottis
During swallowing, what do the muscles of the neck and pharynx do that is important?
Help prevent particles from entering the glottis
What does the submucosa contain?
C-shaped tracheal cartilages, which stiffen the tracheal walls and protect the airway
Why does the posterior tracheal wall distort?
To permit large masses of food to pass through the esophagus
What does the trachea branch within the mediastinum to form?
The right and left main bronchi
Where does each bronchus enter a lung?
At the hilum (a groove)
What is the root of the lung?
A connective tissue mass that includes the bronchus, pulmonary vessels, and nerves
What do the main bronchi and their branches form?
The bronchial tree
What happens when the lobar and segmental bronchi branch within the lungs?
The amount of cartilage in their walls decrease and the amount of smooth muscle increases
Each tertiary bronchus supplies air to a single ____
Bronchopulmonary segment
What do bronchioles within the bronchopulmonary segment ultimately branch into?
Terminal bronchioles
What does each terminal bronchiole deliver air to?
A single pulmonary lobule in which the terminal bronchiole branches into respiratory bronchioles
The connective tissues of the root of the lung extend into…?
The parenchyma of the lung as a series of trabeculae
What do trabeculae branch to form?
Interlobular septa
What do interlobular septa do in the lungs?
Divide the lungs into lobules
What do the respiratory bronchioles open into?
Alveolar ducts, where many alveoli are interconnected
Where are the respiratory exchange surfaces connected to the circulatory system?
Capillaries of the pulmonary circuit
What does the blood air barrier consist of?
A simple squamous epithelium
The endothelial cell lining an adjacent capillary
Their fused basement membranes
What do pneumocytes type II scattered in the blood air barrier produce?
Surfactant that reduces surface tension and keeps the alveoli from collapsing
What do alveolar macrophages do?
Patrol the epithelium and engulf foreign particles
What are the lobes of the lungs separated by?
Fissures
How many lobes does each lung have?
Right - 3
Left - 2
What do the anterior and lateral surfaces of the lungs follow?
The inner contours of the rib cage
What is the concavity of the medial surface of the left lung called?
The cardiac notch, which conforms to the shape of the pericardium
Where does the respiratory exchange surfaces receive blood from?
Arteries of the pulmonary circuit
Where do the conducting portions of the respiratory tract receive blood from?
The bronchial arteries
Where does most of the returning venous blood flow into?
The pulmonary veins, bypassing the rest of the systemic circuit and diluting the oxygenated blood leaving the alveoli
What is each lung surrounded by?
A single pleural cavity lined by a pleura (serous membrane)
What are the two types of pleurae?
Parietal pleura
Visceral pleura
What does the parietal pleura cover?
The inner surface of the thoracic wall?
What does the visceral pleura cover?
The lungs
What is external respiration?
The exchange of oxygen and CO2 between interstitial fluid and the external environment
What does external respiration include?
Pulmonary ventilation (breathing)
What is internal respiration?
The exchange of oxygen and CO2 between interstitial fluid and cells
Describe and differentiate between external and internal respiration.
External respiration moves gases from outside of the body into the lungs, and then the blood. Internal respiration is the gas exchange between the blood and the tissues. Both being linked through the circulatory system, the two combined described the process of getting oxygen from outside the body to the tissues.
If the oxygen content declines, the affected tissues suffer from ____
Hypoxia
If the oxygen supply is completely cut off, what results?
Anoxia and tissue death
What is pulmonary ventilation
The physical movement of air into and out of the respiratory tract
Decreasing the volume of a gas increases ____
Its pressure
Increasing the volume of a gas decreases _____
Its pressure
What is Boyle’s law?
The inverse relationship between gas and pressure
What does movement of the diaphragm and ribs change?
Lung volume
What are the primary respiratory muscles?
The diaphragm
External intercostal muscles
What determines the direction of airflow?
The relationship between intrapulmonary pressure and atmospheric pressure
What is intrapulmonary pressure?
The pressure inside the respiratory tract
What is intrapleural pressure?
The pressure in the potential space between the parietal and visceral pleurae
What is a respiratory cycle?
A single cycle of inhalation and exhalation
What is the tidal volume?
The amount of air moved in one respiratory cycle
What is a spirometer?
An instrument used to measure the capacity of the lungs
What is alveolar ventilation?
The amount of air reaching the alveoli each minute
What does the tidal capacity include?
The tidal volume and the expiratory/inspiratory reserve volumes
What is residual volume?
The air left in the lungs at the end of maximum exhalation
What is Dalton’s law?
Each gas in a mixture exerts a pressure equal to its relative abundance.
What is partial pressure?
The pressure contributed by a single gas
What is Henry’s law?
The amount of a gas in solution is directly proportional to the partial pressure of that gas
What do alveolar and atmospheric air differ in?
Composition
Gas exchange across the blood air barrier is efficient due to:
Differences in partial pressure
The short diffusion distance
Lipid-soluble gases
The large surface area of all the alveoli combined
The coordination of blood flow and airflow
What does blood entering peripheral capillaries deliver and absorb?
Delivers oxygen
Absorbs CO2
How is oxygen carried?
Mainly by RBCs, reversibly bound to hemoglobin
What is the saturation level of hemoglobin at alveolar P(O2)?
Almost fully saturated
At the P(O2) of peripheral tissues, what happens to oxygen?
It is released but the peripheral tissues still retain a substantial oxygen reserve
What is the Bohr effect?
The effect of pH on the hemoglobin saturation curve
When low plasma P(O2) continues for extended periods, RBCs generate…?
BPG
What does BPG do?
Reduces hemoglobin’s affinity for oxygen
What does fetal hemoglobin have a stronger affinity for than adult hemoglobin? Why is this important?
Oxygen. Fetal hemoglobin aids in the removal of oxygen from maternal blood
What does aerobic metabolism in peripheral tissues generate?
CO2
How is the CO2 in blood dispersed?
70% transported as bicarbonate ions (HCO3-)
23% bound as carbaminohemoglobin
7% is dissolved in the plasma
Driven by differences in partial pressure, what does oxygen do?
Enters the blood at the lungs and leaves it in peripheral tissues
The cellular rates of gas absorption and generation are matched by?
The capillary rates of delivery and removal
Identical to the rates of oxygen absorption and CO2 removal at the lungs
What is alveolar blood flow?
Lung perfusion
What is airflow?
Alveolar ventilation
When would alveolar capillaries constrict?
Under conditions of low oxygen
When would bronchioles dilate?
Under conditions of high CO2
What do the respiratory centers include?
3 pairs of nuclei in the reticular formation of the pons and medulla oblongata
What do the respiratory rhythmicity centers set the pace for?
Respiration
What do the apneustic centers cause?
Strong, sustained inspiratory movements
What do the pneumotaxic centers do?
Inhibit the apneustic centers
Promote exhalation
What is stimulation of the chemoreceptor reflexes based on?
The level of CO2 in the blood and CSF
What does the inflation reflex prevent?
Overexpansion of the lungs during forced breathing
What does the deflation reflex stimulate?
Inhalation when the lungs are collapsing
What are the fetal lungs filled with before delivery?
Amniotic fluids. The lungs are collapsed
What happens at the first breath in newborns?
The lungs inflate and do not collapse completely thereafter
Why is the respiratory system less efficiency in the elderly?
Elastic tissue deteriorates, lowering compliance and the vital capacity of the lungs
Movements of the chest are restricted by arthritic changes and decreased flexibility in costal cartilages
Some degree of emphysema is present
What system does the respiratory system have extensive anatomical and physiological connections with?
The cardiovascular system
What type of epithelium lines the conducting portion of the respiratory tract?
Pseudostratified ciliated columnar epithelium
List the two anatomical divisions of the respiratory system.
The upper respiratory system and the lower respiratory system
What membrane lines the conducting portion of the respiratory tract?
The respiratory mucosa lines the conducting portion of the respiratory tract
Why is the vascularization of the nasal cavity important?
The rich vascularization of the nose delivers body heat to the nasal cavity, so inhaled air is warmed before it leaves the nasal cavity and moves toward the lungs. The heat also evaporates moisture from the epithelium to humidify the incoming air.
Why is the lining of the nasopharynx different from that of the oropharynx and the laryngopharynx?
The lining of the nasopharynx, which receives air from only the nasal cavity, is the same as that of the nasal cavity: a pseudostratified ciliated columnar epithelium. Because the oropharynx and laryngopharynx receive air from the nasal cavity and potentially abrasive food from the oral cavity, they have a more protective lining: a stratified squamous epithelium.
Identify the unpaired and paired cartilages associated with the larynx.
The unpaired laryngeal cartilages include the thyroid cartilage, cricoid cartilage, and epiglottis. The paired cartilages are the arytenoid cartilages, corniculate cartilages, and cuneiform cartilages.
List the functions of the trachea.
The trachea conveys air between the larynx and main bronchi; cilia and the mucus produced by epithelial cells also protect the respiratory tree by trapping inhaled debris and sweeping it toward the pharynx, where it is removed through coughing or swallowing.
Why are the cartilages that reinforce the trachea C-shaped?
The tracheal cartilages are C-shaped to allow space for expansion of the esophagus when food or liquid is swallowed.
If food accidentally enters the main bronchi, in which bronchus is it more likely to lodge? Why?
Objects are more likely to be lodged in the right main bronchus because it is slightly larger and more vertical than the left main bronchus.
What type of muscle wraps around a respiratory bronchiole and can change the diameter of the airway?
Smooth muscle wraps around a respiratory bronchiole and can change the diameter of the airway.
What would happen to the alveoli if surfactant were not produced?
Without surfactant, the alveoli would collapse as a result of surface tension in the thin layer of water that moistens the alveolar surfaces.
Trace the path air takes in flowing from the glottis to the blood air barrier.
Air passing through the glottis flows into the larynx and through the trachea. From there, the air flows into a main bronchus, which supplies the lungs. In the lungs, the air passes to lobar bronchi, segmental bronchi, bronchioles, a terminal bronchiole, a respiratory bronchiole, an alveolar duct, an alveolar sac, an alveolus, and ultimately to the blood air barrier.
How many lobes does each lung have, and which lung has a cardiac notch?
The right lung has three lobes, the left lung has two lobes, and the left lung has a cardiac notch.
Which arteries supply blood to the gas-exchange surfaces and conducting portions of the respiratory system?
The pulmonary arteries supply blood to the gas-exchange surfaces; the bronchial capillaries, supplied by the bronchial arteries, which branch from the thoracic aorta, supply the conducting portions of the respiratory system.
List the functions of the pleura.
The pleura is a serous membrane that secretes pleural fluid, which lubricates the opposing parietal and visceral surfaces to prevent friction during breathing.
Define external respiration and internal respiration.
External respiration includes all the processes involved in the exchange of oxygen and carbon dioxide between the body’s interstitial fluids and the external environment. Internal respiration is the absorption of oxygen and the release of carbon dioxide by the body’s cells.
Name the integrated steps involved in external respiration.
The integrated steps involved in external respiration are pulmonary ventilation (breathing), gas diffusion across the blood air barrier, and the transport of oxygen and carbon dioxide.
Name the primary muscles of respiration.
The primary muscles of respiration are the diaphragm and the external intercostal muscles.
Define compliance and identify the factors that affect it.
Compliance is the ease with which the lungs expand. Factors affecting compliance include (a) the connective tissue structure of the lungs, (b) the level of surfactant production, and (c) the mobility of the thoracic cage.
Name the various measurable pulmonary volumes
Tidal volume, expiratory reserve volume, residual volume, and inspiratory reserve volume
Mark breaks a rib that punctures the chest wall on his left side. What is likely to happen to his left lung as a result?
When the rib penetrates Mark’s chest wall, it also penetrates the left pleural cavity, allowing atmospheric air to enter and increase the intrapleural pressure within the pleural cavity (a condition called pneumothorax). As a result, the natural elasticity of the left lung may cause the lung to collapse, a condition called atelectasis.
In pneumonia, fluid accumulates in the alveoli of the lungs. How would this accumulation affect vital capacity?
Because the fluid produced in pneumonia takes up space that would normally be occupied by air, vital capacity would decrease.
More oxygen is released when the pH is (higher or lower) than normal and when temperature is (higher or lower) than normal.
More oxygen is released when the pH is lower than normal and when temperature is higher than normal.
Identify the three ways that carbon dioxide is transported in the bloodstream.
Carbon dioxide is transported in the bloodstream as bicarbonate ions, bound to hemoglobin, or dissolved in the plasma.
As you exercise, hemoglobin releases more oxygen to active skeletal muscles than it does when those muscles are at rest. Why?
During exercise, active skeletal muscles generate heat, lactate, and hydrogen ions. A combination of increased body temperature and decreased pH causes hemoglobin to release more oxygen when you are exercising than when you are resting.
How would blockage of the trachea affect blood pH?
Blockage of the trachea would interfere with the body’s ability to gain oxygen and eliminate carbon dioxide. Because most carbon dioxide is transported in blood as bicarbonate ions formed from the dissociation of carbonic acid, an inability to eliminate carbon dioxide would result in an excess of hydrogen ions, which decreases blood pH.
Inhibition of medulla oblongata chemoreceptors and respiratory muscles has what effect on respiratory rate, elimination of CO2 at alveoli, and arterial P(CO2)?
It will decrease respiratory rate, the elimination of CO2 at alveoli, and increase arterial P(CO2)
What effect does exciting the pneumotaxic centers have on respiration?
Exciting the pneumotaxic centers would inhibit the inspiratory and apneustic centers, which would result in shorter and more rapid breaths.
Are peripheral chemoreceptors more or less sensitive to the level of carbon dioxide than they are to the level of oxygen? Why?
Peripheral chemoreceptors are more sensitive to the carbon dioxide level than to the oxygen level. When carbon dioxide dissolves, it forms carbonic acid, which dissociates and releases hydrogen ions, thereby decreasing pH and altering cell or tissue activity.
Little Johnny is angry with his mother, so he tells her that he will hold his breath until he turns blue and dies. Is Johnny likely to die if he holds his breath as long as he can?
Johnny isn’t likely to turn blue and die. When he holds his breath, the blood carbon dioxide level is increasing, causing increased stimulation of the inspiratory center and forcing him to breathe again.
Identify the functional relationship between the respiratory system and all other organ systems.
The respiratory system provides oxygen and eliminates carbon dioxide for all body systems.
Describe the functional relationship between the respiratory system and the lymphatic system.
The respiratory system provides alveolar phagocytes and respiratory defenses to trap pathogens and protect deeper tissues. Tonsils within the lymphatic system protect against respiratory infection, and lymph drainage from the lungs mobilizes defenses to ward off infection.
