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List the four functions of the respiratory system as discussed in class.
- Provide oxygen to the blood and remove carbon dioxide.
- Vocalization or sound production.
- Assist in abdominal compression during urination, defecation,and parturition.
- Protective and reflexive nonbreathing air movements
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The physiological processes of respiration extend from the conducting zone to cells throughout the body and consists of four aspects of respiration. List the four aspects.
- ventilation (breathing)
- external respiration (the exchange of gases within the alveoli of the lungs)
- internal respiration (the exchange of gases between the blood and the tissues throughout the body)
- cellular respiration (the use of oxygen with mitochondria to produce ATP)
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What is the anatomical term for the microscopic air sac within the lungs?
alveoli (plural, singular = alveolus)
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What is the approximate surface area within the lungs?
60-80 square meters (about 760 square feet)
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What two types of cells make up the walls of the alveoli?
type I alveolar cells and type II alveolar cells
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What type of alveolar cells make up 95% to 97% of the surface area of the lungs?
type I alveolar cells
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What is the function of type II alveolar cells?
to secrete surfactant and reabsorb Na+ and water to prevent fluid build up
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What gives strength to the walls of the alveoli?
collagen proteins
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What is the respiratory zone of the respiratory system?
the region in which gas exchange takes place
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What is the conducting zone of the respiratory system?
all of the anatomical structures through which air passes before reaching the respiratory zone
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What are the functions of the conducting zone of the respiratory system?
to direct air to the respiratory zone and, along the way, filter and moisten it and bring its temperature to that of the body core (about 370 Celius)
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From the outside of the body to the inside, what cavity does air first enter during quiet breathing?
the nasal cavity
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What structure divides the nasal cavity into two compartments?
the nasal septum
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What are the skeletal elements of the nasal septum?
- the perpendicular plate of the ethmoid
- the vomer
- the septal cartilage
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What structures on the lateral wall of the nasal cavity increase surface area and set the air into a turbulence as it passes?
nasal conchae or turbinate bones
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What are the air-filled cavities that lie within bones surrounding the nasal cavity?
paranasal sinuses
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List the four sets of paranasal sinuses.
- ethmoidal
- sphenoidal
- maxillary
- frontal
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What is the funnel-shaped passageway that connects the nasal and oral cavities to the larynx and the esophagus?
the pharynx
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What is the anatomical term for the voice box?
the larynx
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What are the functions of the larnyx?
- to prevent food from entering the trachea
- to produce sound
- to aid in creating abdominal compression and protective, reflexive nonbreathing air movements.
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What is the opening between the vocal cords?
the glottis
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What is the anatomical term for the windpipe?
the trachea
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What structures within the trachea provide support to prevent its collapse?
C-shaped cartilages
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The trachea bifurcates into what two structures?
the left and right primary bronchi
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The primary bronchi branch into what structures?
bronchioles
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What tissue type lines the trachea and the bronchial tree?
pseudostratified ciliated columnar epithelium
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What is the dome-shaped muscle separating the thoracic and abdominal cavities?
the diaphragm
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What is the space in the thorax between the pleural sacs of the lungs that contains all the viscera of the chest except the lungs and pleurae?
the mediastinum
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What serous membrane surrounds the lungs?
the pleura
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What portion of the pleura lines the wall of the thorax?
the parietal plura
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What portion of the pleura lies directly on the lungs?
the visceral pleura
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What lies between the parietal and visceral pleurae?
the intrapleural space
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What normally fills the intrapleural space?
serous fluid
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What is the pressure within the alveoli?
intrapulmonary pressure (intra-alveolar pressure)
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What term describes the pressure between the parietal pleura and the visceral plura?
intrapleural pressure
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What is the normal relation between the intrapleural pressure and the intrapulmonary pressure?
- Intrapleural pressure is always less than intrapulmonary pressure. This keeps the lungs in
- contact with the thoracic wall.
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What law of physics states that the pressure of a gas is inversely proportional to its volume?
Boyle's law
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If the volume of a gas increases, what happens to the pressure?
It deceases
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If the volume of gas decreases, what happens to its pressure?
It increases
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What is the ability of the lungs to yield elastically when a force is applied to them?
compliance
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What physical quality of the lungs allows them to recover their original shape and size after expanding?
elasticity
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What physical property of the lungs will cause them to leave the thoracic wall should air or blood ever enter the intrapleural space?
elasticity
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What is the attractive force exerted upon the surface molecules of a liquid by the molecules beneath that tends to draw the surface molecules into the bulk of the liquid and makes the liquid assume the shape having the least surface area?
surface tension
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What creates surface tension within water?
hydrogen bonds
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What type of molecule reduces surface tension within the lungs?
surfactant
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What is the function of surfactant within the lungs?
It reduces surface tension and thus prevents the alveoli from collapsing during expiration
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What condition occurs within the lungs when surfactant is not produced and fluid is drawn into the alveoli?
respiratory distress syndrome (RDS)
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What condition occurs in the lungs as a result of inflammation causing fluid to accumulate in the alveoli and reduced production of surfactant thus leading to hypoxemia?
acute respiratory distress syndrome (ARDS)
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What is the medical term for breathing in?
inspiration
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What muscle is used during quiet inspiration?
the diaphragm
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What is the immediate result of the contraction of the diaphragm?
the lowering of the floor of the thoracic cavity
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List several muscles that aid in forced inspiration.
- intercostals
- scalenes
- pectoralis minor
- sternocleidomastoid
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What is the medical term for breathing out?
expiration
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What action leads to expiration during quiet breathing?
relaxation of the diaphragm
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What the immediate result of relaxation of the diaphragm?
The abdominal viscera force it superiorly thus raising the floor of the thoracic cavity
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What change occurs in the volume of the thoracic cavity during inspiration?
volume increases
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What change occurs in the intrapulmonary pressure during inspiration?
It decreases
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During inspiration the volume of the thoracic cavity increase and pressure decreases. What event results from these changes?
Atmospheric pressure pushes air into the lungs
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What change in the volume of the thoracic cavity occurs during expiration?
It decreases
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What change occurs to intrapulmonary pressure during expiration?
It increases
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During expiration the volume of the thoracic cavity decrease and intrapulmonary pressure increases. These changes bring about what action?
Intrapulmonary pressure becomes greater than atmospheric pressure and air is pushed out of the lungs
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List several muscles that aid in forces expiration.
internal intercostals, muscles of the abdominal wall
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How do intercostals and abdominal muscles bring about forced expiration?
They lower the rib cage and compress the abdomen
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How do muscles of the thorax and neck aid in forced inspiration?
They raise the rib cage
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What is medical term for the amount of air expired with each breath during quiet breathing?
tidal volume
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What is the maximum amount of air that can be forcefully exhaled after a maximum inhalation?
vital capacity
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Vital capacity is the sum of what respiratory volumes?
- inspiratory reserve volume
- tidal volume
- expiratory reserve volume
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What medical term refers to the tidal volume multiplied times the breaths per minute?
total minute volume
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What the average total minute volume during quiet breathing?
6 L/min.
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What is the normal range of the total minute volume during exercise?
100-200 L/min.
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What is the space in the respiratory system in which air does not undergo significant gas exchange?
the anatomical dead space
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What is the average volume of the anatomical dead space?
150 ml
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What type of pulmonary disorder reduces the vital capacity?
restrictive
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What type of pulmonary disorder obstructs airways?
obstructive
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In what pulmonary disorder does obstruction of bronchioles by constriction, mucus production, and inflammation occur?
asthma
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What pulmonary disorder involves the destruction of alveolar and connective tissues in the lungs?
emphysema
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What pulmonary disorder involves chronic bronchitis and emphysema accompanied by edema, inflammation, hyperplasia, pulmonary fibrosis, pneumonia, pulmonary emboli, and heart failure?
chronic obstructive pulmonary disease (COPD)
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What pulmonary disorder involves the accumulation of fibrous connective tissue?
pulmonary fibrosis
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What term refers to the portion of the total pressure produced by a particular gas in a mixture of gases?
partial pressure
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In a liquid, what factors influence the partial pressure of a gas?
- solubility of the gas
- the temperature of the liquid
- the partial pressure of the gas in the bordering gas or liquid
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What is the normal partial pressure of oxygen in arterial blood?
100 mm Hg
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What is the normal partial pressure of carbon dioxide in arterial blood?
40 mm Hg
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What is the normal partial pressure of oxygen in venous blood?
40 mm Hg
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What is the normal partial pressure of carbon dioxide in venous blood?
46 mm Hg
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What is the normal partial pressure of oxygen in the alveoli?
105 mm Hg
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What is the normal partial pressure of carbon dioxide in the alveoli?
40
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Where are the central chemoreceptors and the rhythmicity center for respiration?
the medulla oblongata
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What part of the brain plays an influential role on the rhythmicity center of the medulla oblongata?
the pons
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Where the peripheral chemoreceptors which respond to changes in the pH of the blood and thus influence the rate of breathing?
In the aortic arch and the carotid sinus
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What are the peripheral chemoreceptors which respond to changes in the pH of the blood and thus influence the rate of breathing?
the aortic bodies and carotid bodies
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What two factors most immediately influence the rate of breathing?
the partial pressure of carbon dioxide and pH
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What effect does an increase in the partial pressure of arterial carbon dioxide have on the rate of breathing?
It increases it
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What effect does a decrease in the pH of arterial blood have on the rate of breathing?
It increases it
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What effect does a decrease in the partial pressure of arterial blood have on the rate of breathing?
It decreases it
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What effect does an increase in pH have on the rate of breathing?
It decreases it
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Write the reaction that occurs between carbon dioxide and water.
CO2 + H2O > H2CO3 > H+ + HCO3-
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Chemoreceptors in the medulla oblongata respond to changes in the pH of CSF. What substance from the blood crosses the blood-brain barrier and influences the pH of CSF?
carbon dioxide
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Peripheral respiratory chemoreceptors respond to what factor in the blood?
H+
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How does the partial pressure of oxygen affect breathing?
It does so indirectly by influencing receptor sensitivity to the partial pressure of carbon dioxide.
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What prevents damage to the lungs that might occur due to excessive inspiration?
pulmonary stretch receptors
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What sensor respond to irritating materials entering the lungs?
irritant receptors
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What is the response of the lungs to irritants?
an increase in bronchosecretion and bronchoconstriction
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What substance carries most of the oxygen in the blood?
hemoglobin
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What is the general structure of hemoglobin?
It consists of four polypeptide chains, each of which has a heme group with a single ferrous iron ion within it
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What portion of hemoglobin associates with oxygen?
the ferrous iron (Fe++) within the four heme groups
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What abnormal condition involves a below normal hemoglobin level?
anemia
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What is the hormone which stimulates the production of hemoglobin?
erythropoietin
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What organs makes erythropoietin?
the kidneys
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The kidneys make erythropoietin in response to what?
low oxygen levels in the blood
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What type of graph shows the relationship of the partial pressure of oxygen to the percent saturation of hemoglobin?
the oxyhemoglobin dissociation curve
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As the pH of blood decreases and body temperature increases, what happens to the oxyhemoglobin dissociation curve?
It shifts to the right
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What is the significance of the right shift that occurs in the oxyhemoglobin dissociation curve as the pH of the blood decreases and body temperature rises?
More oxygen is delivered to the tissues
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What molecule does 2,3-diphosphoglyceric acid bind to?
hemoglobin
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What is the effect of 2,3-diphosphoglyceric acid on hemoglobin?
It promotes oxygen unloading
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Where is 2,3-diphosphoglyceric acid made?
In red blood cells
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What promotes the production of 2,3-diphosphoglyceric acid?
- a drop in oxygen levels
- an increase in body temperature (fever)
- thyroxine
- growth hormone
- testosterone
- epinephrine
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What type of hemoglobin occurs in the fetus?
fetal hemoglobin (hemoglobin F)
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What is the relation of 2,3-diphosphoglyceric acid to fetal hemoglobin?
2,3-diphosphoglyceric acid will not bind to fetal hemoglobin. This allows fetal hemoglobin to pick up oxygen from the mother
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What are the three ways that carbon dioxide is transported in the blood? What percent of the carbon dioxide in the blood is transported in each form?
- dissolved 10%
- carbaminohemoglobin 20%
- bicarbonate 70%
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What enzyme catalyzes the reaction between carbon dioxide and water?
carbonic anhydrase
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Carbonic anhydrase catalyzes the reaction between carbon dioxide and water in the blood. Where is it found as it promotes this reaction?
In the red blood cells
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In relation to the acid-base balance in the blood, what condition occurs as a result of hypoventilation?
respiratory acidosis
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In relation to the acid-base balance in the blood, what condition occurs as a result of hyperventilation?
respiratory alkalosis
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