Chapter 22

intrapleural pressure is equal to intrapulmonary pressure. Intrapleural pressure (Ppul) is the gas pressure within the pleural cavity, while intrapulmonary pressure (Pip) is the gas pressure within the alveoli. Normally Ppul is less than Pip to maintain lung expansion. If Ppul exceeds Pip, then the lungs collapse.

the intrapleural pressure would not decrease normally during inhalation. As the size of the thoracic cavity increases, so does its volume. This causes intrapleural pressure to go below atmospheric pressure so that air (gases) can move into the lungs during inspiration. If the thoracic cavity cannot change its size (volume), then intrapleural pressure will not decrease and normal air movement will not occur.

hypoxia. Hypoxia occurs when too little oxygen is delivered to the tissues. Low carbon dioxide levels stimulate chemoreceptors in the brain and great vessels that signal the respiratory centers of the brain to slow down the respiratory rate. As rate falls, so does the rate of external respiration leading to lower oxygen saturation.

the infection has caused inflammation of the nasolacrimal ducts.

lymphocytes The adenoids (pharyngeal tonsils), which are located in the posterior wall of the pharynx posterior to the soft palate, are part of a ring of lymphatic tissue surrounding the entrance to the laryngopharynx. They function to trap inhaled bacteria and facilitate activation of resident lymphocytes.

All of the listed responses are correct.

dynein molecules. Dynein is a motor protein that moves cilia causing them to bend. Collectively cilia propel other substances (like mucus) across the cell's surface.

larynx. The larynx is superior to the trachea in the respiratory tract. The laryngeal opening (glottis) is covered by the epiglottis during swallowing, normally preventing ingested materials from passing into the trachea.

visceral pleura of the same lung. Normally the visceral and parietal pleura of one lung glide easily over one another during breathing because they are smooth and lubricated by pleural fluid. During pleurisy, they become rough and friction develops between the two layers.

release of histamine and inflammatory chemicals in the airway walls. Acute asthma attacks are usually associated with an allergen-induced local release of histamine and other inflammatory chemicals in the airways.

due to insufficient exocytosis in the type II alveolar cells. Type II alveolar cells make surfactant which they release via exocytosis onto the inner wall of alveoli. Without surfactant, the surface tension created by the water vapor within the alveoli would cause them to collapse.

costal cartilages. Cartilage is normally avascular and receives oxygen by diffusion from surrounding capillaries.

interstitial fluid. Pneumonia is an infection within the lung tissue often accompanied by inflammation. In response to inflammation, the increased permeability of the respiratory membrane results in increased formation of interstitial fluid that enters the alveoli.

All of the listed responses are correct.

the presence of air or gas in the cavity between the lungs and the chest wall, causing collapse of the lung.

excessive carbon dioxide in the blood.

smallest branches of the bronchi, measuring less than 1 mm.

nitrogen Nitrogen (N2) is poorly soluble in water. Under normal atmospheric pressures, nitrogen does not enter/leave our body fluids like oxygen (O2) and carbon dioxide (CO2). Therefore, under ordinary circumstances, nitrogen has no physiological significance in the body.

ventral respiratory group (VRG)

Phrenic Nerve

H+ (hydrogen ions) hydrogen ions (H+) stimulate the central chemoreceptors. CO2 is converted to H+ in the extracellular fluid of the brain.

decreased pCO2 and increased pH pCO2 would decrease and pH would increase. As CO2 is blown off, H+ would decrease, thus increasing pH.

pulmonary stretch receptors

sensory input from receptors in joints, neural input from the motor cortex, and other factors

respiratory muscles. the respiratory muscles change the volume of the thoracic cavity (and thus the pressure), resulting in inspiration and expiration.

pulmonary ventilation and external respiration

external respiration: CO2 diffuses into the blood stream. CO2 diffuses into the blood as it passes through the systemic capillaries of the tissues; this is internal respiration.

False. The separation between the upper and lower respiratory system occurs at the larynx. The upper respiratory system consists of all the structures from the nose to the larynx. The lower respiratory system consists of the larynx and all the structures below it.

the production of smooth, laminar airflow as air passes by the nasal conchae. In fact, airflow becomes turbulent (not smooth or laminar) as the gases of inhaled air swirl through the twists and turns created by the curved nasal conchae protruding medially from each lateral wall of the nasal cavity. Heavier, nongaseous particles deflect onto the mucus-coated surfaces, where they become trapped. As a result, few particles larger than 6 μm make it past the nasal cavity.

pharynx. The funnel-shaped pharynx connects the nasal cavity and mouth superiorly to the larynx and esophagus inferiorly. Commonly called the throat, the pharynx is the site where our respiratory pathway, from nose to larynx, crosses the digestive pathway, from mouth to esophagus.

paranasal sinuses: house olfactory receptors. The sinuses contain open spaces that lighten the skull and may help to warm and humidify air entering the respiratory system. The sinuses are all outside of the nasal cavity, which is where the odor receptors would be found.

True

True

True

temporal

as the direct initiator of the cough reflex

ciliated mucous lining in the nose.

oropharynx

routing air and food into proper channels. While the nasal conchae are used for routing air, they are not involved in routing food. The nasal conchae are coated with membrane that has a rich blood supply; this cleans, humidifies, and warms incoming air.

nasopharynx.

alveoli. Along with the respiratory bronchioles and alveolar ducts, the alveoli make up the respiratory zone.

epiglottis. During swallowing, the larynx is pulled superiorly and the epiglottis tips to cover the laryngeal inlet. Because this action keeps food out of the lower respiratory passages, the epiglottis has been called the guardian of the airways.

False. Respiratory system organs are divided functionally into conducting zone structures (nose to terminal bronchioles), which filter, warm, and moisten incoming air; and respiratory zone structures (respiratory bronchioles and alveolar ducts to alveoli), where gas exchanges occur.

False.

True

True

True

force with which air rushes across the vocal folds.

secret surfactant.

C-shaped cartilage rings.

higher in pitch.

the thyroid cartilage.

alveoli.

single layer of smooth muscle cells.

alveolus.

arytenoid cartilages.

terminal bronchiole.

Segmental bronchi : No exchange of gases occurs here.

Type II cells : Secrete a fluid containing surfactant.

Respiratory bronchioles : Where the respiratory zone of the lungs begins.

Type I cells : Form a simple squamous epithelium in the alveoli.

Alveolar duct : Terminates in alveoli.

Type II cells : Are cuboidal cells.

The respiratory membrane consists of 3 layers: capillary endothelium, fused basement membrane and alveolar epithelium consisting of Type I cells.

epiglottis. When the larynx is elevated during the act of swallowing, the epiglottis is pressed over the glottis to prevent swallowed food from entering the lower respiratory passages.

arytenoid cartilage.

cricoid cartilage. The cricoid cartilage makes a complete ring around the airway, stabilizing the glottis, the vocal cords, and the epiglottis.

alveolar macrophages. Alveolar macrophages wander freely, ingesting and destroying invading microorganisms or foreign matter.

simple squamous epithelium. Squamous epithelia are thin and easily passed through by respiratory gases. The membrane is also kept thin by organizing the squamous cells in a single layer.

type II alveolar cells. Type II alveolar cells secrete a detergent-like surfactant that lessens the surface tension on the alveolar walls, preventing them from sticking to each other. Infants with IRDS can be treated until their cells produce adequate surfactant.

a horizontal fissure.

Pleural fluid is produced by the lung alveoli.

The pleurae create one continuous cavity for both lungs. Each lung has its own, separate pleura. The mediastinum surrounds the heart and vessels in the medial thoracic cavity.

True

False

True

a cardiac notch.

assist in blood flow to and from the heart because the heart sits between the lungs.

surface tension from pleural fluid and negative pressure in the pleural cavity.

pleural cavities.

pulmonary arteries.

hilum.

the diaphragm and rib muscles contract.

Alveoli. Alveoli are tiny sacs in the lungs surrounded by capillaries. The alveoli are where oxygen diffuses from the lungs to the blood.

In the blood, oxygen is bound to hemoglobin, a protein found in red blood cells.

it returns to the heart, and is then pumped to body cells.

is a protein that can bind four molecules of oxygen.

The pressure of gas in your lungs is inversely proportional to the volume in your lungs. Boyle's Law describes how air moves into and out of the lungs during inspiration and expiration. By changing the volume of the thoracic cavity, the pressure changes in the lungs. Increasing volume of the thoracic cavity leads to a decreased pressure, causing air to flow into the lungs (down its pressure gradient) and thus causing inspiration.

diaphragm and external intercostals. contraction of both the diaphragm (the diaphragm flattens) and the external intercostals (pulls the ribs up and out) will increase the volume of the thoracic cavity. This will cause air to move into the lungs (inspiration).

intrapleural pressure. the lungs tend to decrease their size while the chest wall tends to pull the thorax outward. This makes the intrapleural pressure more negative than the other two pressures (described as subatmospheric), thus keeping the lungs inflated.

epinephrine. during an allergic reaction, there is increased resistance in the bronchioles and epinephrine dilates the bronchioles, thus making it easier to breathe. Epinephrine is released from the adrenal gland during stressful situations. People with severe allergies carry an EpiPen in case the allergic reaction produces anaphylaxis.

The lung will collapse. the transpulmonary pressure creates the suction that keeps the lungs inflated. When room air enters the pleural space, transpulmonary pressure is zero and the lungs deflate - this is known as a pneumothorax.

All of the above are correct.

partial pressure of oxygen in the air. Pulmonary ventilation is affected by pressure of air in various respiratory structures. Partial pressures of individual gases in the air affect the diffusion and dissolving of these gasses into and out of the blood.

negative intrapleural pressure. A negative respiratory pressure refers to a pressure that is less than atmospheric pressure (Patm). Intrapleural pressure (Pip) is the negative pressure in the pleural cavity, which creates a partial vacuum between the visceral and parietal pleurae. This partial vacuum (negative Pip), along with the surface tension produced by the pleural fluid, holds the visceral and parietal pleurae together, thereby connecting the lungs to the thorax wall. Equilibration between Patm and Pip, which would occur if air is allowed to enter the intrapleural cavity, will result in lung collapse.

Transpulmonary. The transpulmonary pressure is the difference between the intrapulmonary and intrapleural pressures. It is this pressure that keeps the air spaces of the lungs open, or, phrased another way, keeps the lungs from collapsing.

an active process; a passive process. During quiet breathing, inspiration requires muscular contractions of the diaphragm and external intercostals, while expiration occurs passively due to the elastic recoil of the lungs and the collapsing force of alveolar fluid surface tension.

True. During quiet inspiration, muscular contractions of the diaphragm and external intercostal muscles increase thoracic volume. Due to the coupling of the parietal and visceral pleurae, an increase in thoracic volume results in an increase in lung volume. As illustrated by Boyle's law, this increase in lung volume results in a decrease in lung (intrapulmonary) pressure. With intrapulmonary pressure now lower than atmospheric pressure, the pressure gradient required for airflow into the lungs is achieved.

increased secretion of surfactant. Surfactant decreases the attraction between water molecules lining the interior surface of the alveoli. As a result, the surface tension of alveolar fluid is reduced, and less energy is needed to overcome those forces to expand the lungs during inspiration.

True.

True.

greater than the pressure in the atmosphere.

It is a passive process that depends on the recoil of elastic fibers that were stretched during inspiration.

pressure within the alveoli of the lungs

Boyle's Law.

interfering with the cohesiveness of water molecules, thereby reducing the surface tension of alveolar fluid.

the natural tendency for the lungs to recoil and the surface tension of the alveolar fluid.

Pulmonary ventilation.

Friction.

alveolar surface tension.

Inspiration occurs when the intrapulmonary pressure is less than the atmospheric pressure

internal intercostals and abdominal muscles would contract.

transpulmonary pressure

Pressure gradient equals gas flow over resistance.

As alveolar surface tension increases, additional muscle action will be required.

diaphragm descends, thoracic volume begins to increase, and rib cage rises.

Boyle's Law.

intrapulmonary pressure. Intrapulmonary pressure rises when the thorax volume is reduced (during exhalation) and drops when the thorax volume rises (during inhalation). When there is no change in thorax volume, intrapulmonary pressure equalizes with the atmospheric pressure.

intrapleural pressure. Intrapleural pressure is created as the lungs attempt to shrink away from the thoracic wall. This negative pressure, as well as the adherence due to moisture, is what keeps the lungs from collapsing.

761 millimeters of mercury. The intrapleural pressure is always about 4 millimeters of mercury less than the intrapulmonary pressure, and the intrapulmonary pressure is equal to the atmospheric pressure if the subject is at rest.

When the sternocleidomastoid is activated, expiration occurs. The sternocleidomastoid muscle elevates the ribs, assisting in inspiration.

external intercostals, sternocleidomastoid, diaphragm

the internal intercostal, oblique, and transversus muscles

residual volume.

inspiratory reserve volume.

breathing rate. Restrictive lung diseases decrease vital capacity, total lung capacity, functional residual capacity, and residual volume. To provide adequate ventilation, the alveolar ventilation rate must increase.

slow, deep breathing. Slow breathing provides adequate time for gases to pass into the alveoli, while breathing deeply increases the number of alveoli being utilized. The combination of these factors increases effective ventilation, or alveolar ventilation rate.

tidal volume. A tidal volume is the amount of air in a normal breath under resting conditions. One way to remember this is to compare tidal breathing to ocean tides that go in and out, day and night, without ceasing.

A person with a decreased FVC and a normal FEV1 has a restrictive disorder. Restrictive diseases, such as tuberculosis, decrease FVC but do not affect flow, so FEV1 stays the same.

Rapid shallow breathing can reduce the amount of gas exchange without changing the total amount of gas moved in a minute. Minute ventilation, the total amount of gas moved in a minute, might not be reduced during rapid shallow breathing, but because much of that gas remains in the dead space, less gas is available for gas exchange.

False. Residual volume cannot be measured; it has to be estimated, generally based on the size and sex of an individual. The volume cannot be detected with a spirometer because the volume of residual air left in the lungs at the end of expiration cannot pass through a spirometer to be measured.

False.

True.

False.

exchanged during normal breathing.

tidal capacity.

inspiratory reserve volume.

the total amount of air that can be inspired after a tidal expiration.

restrictive disease.

COPD.

Total lung capacity : TV + IRV + ERV + RV

Vital capacity : TV + IRV + ERV

Functional residual capacity : ERV + RV

Inspiratory capacity : TV + IRV

True.

True.

True.

Dalton's Law.

ventilation-perfusion coupling.

Henry's Law.

partial pressure gradient.

The level of O2 in her blood has decreased because her breathing has stopped. Her alveolar P_O2 will fall, so there is less oxygen to load onto hemoglobin. In her peripheral tissues, the small amount of oxygen that hemoglobin carries will be consumed, leaving these tissues with a bluish tinge.

Barbara's fractured ribs probably punctured her lung tissue and allowed air within the lung to enter the pleural cavity.

partial pressure of oxygen. Partial pressure of oxygen is the primary factor affecting the binding of oxygen with hemoglobin.

as a bicarbonate ion in plasma. About 70% CO2 is transported as bicarbonate. When dissolved CO2 diffuses into RBCs, it combines with water, forming carbonic acid (H2CO3). H2CO3 is unstable and dissociates into hydrogen ions and bicarbonate (HCO3-) ions. Once generated, bicarbonate moves quickly from the RBCs into the plasma, where it is carried to the lungs.

All of the listed responses are correct.

dissolved in plasma. Most CO2 is transported in the blood bound to hemoglobin (forming carbaminohemoglobin) or in the form of bicarbonate ions. The latter occurs as CO2 entering the blood combines with water to form carbonic acid (H2CO3), which then dissociates into hydrogen ions and bicarbonate ions (HCO3−). A very small percentage is dissolved into the plasma.

True. A decrease in temperature increases hemoglobin's binding affinity for O2, making it more difficult to dissociate (unload) O2 from hemoglobin. This is illustrated by the leftward shift of the oxygen-hemoglobin dissociation curve.

anemic hypoxia

False.

False.

False.

False.

decreased pH and increased PCO2.

only about 1.5% of the oxygen carried in blood.

chloride shifting.

too little oxygen in the atmosphere.

More CO2 dissolves in the blood plasma than is carried in the RBCs.

as bicarbonate ions in plasma after first entering the red blood cells.

attached to the heme part of hemoglobin.

95%

hyperbaric oxygen chamber to increase PO2 and clear CO from the body.

number of red blood cells

A 50% oxygen saturation level of blood returning to the lungs might indicate an activity level higher than normal.

nitric oxide.

oxygen

a drop in blood pH. The pH in blood tends to drop when plasma reacts with carbon dioxide, a common condition in tissue. This pH drop causes weakening of the Hb-O2 bond, a phenomenon called the Bohr effect.

as bicarbonate ions in the plasma. Carbon dioxide reacts with water inside RBCs to form carbonic acid, which dissociates into bicarbonate and hydrogen ions. About 70% of carbon dioxide travels in the plasma as bicarbonate.

CO2 ; alveoli

CO2 is much more soluble in blood than O2.

The partial pressure of O2 would decrease, and the partial pressure of CO2 would increase to produce ATP.

O2 would diffuse into the cells, and CO2 would diffuse into the systemic capillaries because the the Po2 would be higher in the systemic capillaries, and the Pco2 would be higher in the tissues.

the molecular weight of the gas.

During external respiration, equilibrium is reached for O2 when the partial pressure for O2 in the pulmonary capillaries and the alveoli are the same.

If lung volume increases, intrapleural pressure decreases, drawing air into the lungs. Boyle's law shows that pressure and volume are inversely related. If the volume of a space increases, the pressure in that space must decrease.

Transpulmonary pressure is usually near 4 mm Hg.

a decrease in lung volume. According to Boyle's law, a decrease in volume will produce an increase in pressure, at least until the air moves and pressures equalize.

an opening in the chest wall that allows the intrapleural pressure to equal atmospheric pressure. If the chest wall is penetrated and air can enter the pleural cavity, the intrapleural pressure will no longer be negative compared to atmospheric pressure. Without a negative intrapleural pressure, there are no forces to prevent lung collapse.

arterial blood carbon dioxide level.

rising CO2 levels. Of all the chemicals influencing respiration, CO2 is the most potent and the most closely controlled. An elevation of only 5 mmHg in arterial PCO2 doubles alveolar ventilation, even when arterial O2 levels and pH haven't changed. When PO2 and pH are below normal, the response to elevated PCO2 is even greater. On the other hand, arterial PO2 must drop substantially, to at least 60 mmHg, before O2 levels become a major stimulus for increased ventilation.

False.

False.

True.

increase in carbon dioxide levels.

rising blood pressure

Medulla and pons.

voluntary cortical control.

helps retain carbon dioxide in the blood.

pontine respirator group (PRG).

ventral respiratory group (VRG).

the cervical plexus

pontine respiratory centers. The pontine respiratory centers transmit impulses to the ventral respiratory group (VRG) of the medulla to smooth the respiratory pattern and modify it based on activities such as exercise and sleeping.

stimulation of stretch receptors in the lungs. The stimulation of stretch receptors in the lungs reduces the urge to inspire air. When the lungs recoil back to a relaxed shape during expiration, the urge to breathe is again initiated (inflation reflex).

acidosis. A low pH in blood indicates a high level of carbon dioxide, which in turn increases the urge to ventilate the lungs.

High-altitude conditions always result in lower-than-normal hemoglobin saturation levels because less O2 is available to be loaded.

concentration of oxygen and/or total atmospheric pressure is lower at high altitudes.

reduced absorption of certain anions from sweat into the sweat duct cells. This channel, in the sweat ducts, facilitates the movement of chloride into and out of cell cytoplasm. When the CFTR protein does not work, chloride is trapped inside cells. Because chloride is negatively charged, this creates a difference in the electrical potential inside and outside the cell, causing cations to cross into the cell. Sodium is the most common cation in the extracellular space, and the combination of sodium and chloride creates the salt that is lost in high amounts in the sweat of individuals with CF.

A cough suppressant, such as dextromethorphan.

Elevated PCO2 and decreased pH.

False.

False.

emphysema.

emphysema.

Pharynx.