Chapter 21 - Respiratory System

Question 1

Rising CO₂ levels are the most powerful respiratory stimulant.

Answer 1

As CO₂ is hydrated in the brain tissue, liberated H+ acts directly on the central chemoreceptors causing a reflexive increase in breathing rate and depth. Low P_CO2 levels depress respiration.

Question 2

______ involves the intermittent realse of expired air as the glottis opens and closes.

Answer 2

Speech

As the length and tension of the voval folds change, the pitch of the sound varies. Generally, the tenser the vocal folds the farster they vibrate and the higher the pitch.

Question 3

Under normal resting conditions (P_O2 = 100 mm Hg), arterial blood is _____ % saturated, and 100 ml of systemic arterial blood contains about _____ ml of O_2.

Answer 3

98; 20

The oxygen content is written as 20% (volume percent).

Question 4

At sea level, the atmosphic pressure is

Answer 4

760 mm Hg (the pressure exerted by a column of mercury 760 mm high)

760 mm Hg = 1 atm

Question 5

The lungs are perfused by two circulations:

Answer 5

The pulmonary circulation

The bronchial circulation

Differ in size, origin and function.

Question 6

Submucosa

Answer 6

Connective tissue layer dep tot he mucosa.

Contains seromucus glands that help rooudce mucus “sheets” within the trachea.

Supported by 16-20 C-shaped rings of hyaline cartilage encaded by the adverntitia, the outermost later of connective tissue.

Question 7

Internal and External Respiration are driven by ______ diffusion. They are also driven by partial pressure gradients of O2 and CO2 that exist on the opposite sides of the exchange membranes.

Answer 7

Simple

Question 8

During forced or deep inspiration, accessory muscles further increase the thoracic volume. Several muscles, including the ______ and ______ muscles of the neck and the _______ ________ of the chest, rasie the ribs even more than during quiet inspirations.

The back extends as the the _____ ______ muscles straighten the throacic curvature.

Answer 8

Scalenes; Sternocleidomastoid

Pectoralis Minor

Erector Spinae

Question 9

Dorsal Respiratory Group (DRG)

Answer 9

Integrates input from peripheral stretch and chemoreceptors and communicates this information to the VRG.

Question 10

The tissue composition of the walls of th main bronci mimics that of the trachea, however, the conducting tubes become smaller, the following structural chagnes occur:

Answer 10

1. Support structures change - Irrecgular patches of cartilage replace the cartilage ringes, and by the time the broncioles are reached, the tube walls no longer contain supportive cartialge.

The tube walls throughout the broncial tree contain elastic fibers.

2. Epithelium changes - Tthe mucosal epithelium thins as it changes from pseudostratified columnar to simple columnar and then to simple cuboidinal in the terminal bronchioles. Most airborne debris found at or below the level of the broncioles must be removed by macrophages in the alveoli.

3. Amount of smooth muscle increases - A complete layer of circular smooth muscle in the bronchioles and the lack of supporting catilage allows the bronchioles to provide substantial resistnace to air passage under certin conditions.

Question 11

Chronic inflammation, or infections such as tuberculosis, can cause _____ _____ tissue to replace normal lung tissue.

Answer 11

Nonelastic Scar

Decreased produciton of surfactant can also decrease lung compliance, the more energy is needed to breath.

Question 12

Increased ventilation in response to metabolic needs is called ______.

Answer 12

Hyperpnea

Question 13

The lungs are innervated by ________ and ________ motero fibers and visceral sensory fibers.

Nerve fibers enter each lung through the _____ _____ on the lung root and run along the broncial tubes and blood vessesl in the lungs.

Parasympathetic fibers cause the air tubes to ______, whereas sympathetic fibers _____ them.

Answer 13

Parasympathetic; Sympathetic

Pulmonary Plexus

Constrict; Dilate

Question 14

Once inside the lungs, each main broncus subdivides into _____ (secondary) bronchi - _____ on the right and ____ on the left - each supplying one lung lobe.

Answer 14

Lobar

Three; Two

Question 15

Spirometer

Answer 15

A cumbersome instrument utilizing a hollow bell inverted over water, now patients blow into a small electronic measuring device.

Question 16

Declining blood pH (acidosis) and increasing PCO2 weaken the Hb-O₂ bond, a phenomenom called the ______ ______.

Answer 16

Bohr Effect

This enhances oxygen unloading where it is needed the most.

Question 17

When you move on a long-term basis from sea level to the mountains your body makes respiratory hematopoietic adjustments via an adaptive response called _________.

Answer 17

Acclimatization

Question 18

Vital Capacity (VC)

Answer 18

The total amount of exchangeable air.

VC = TV + IRV + ERV

Question 19

The trachea’s _____ ______ make it flexible enough to stretch and move inferiorly during inspiration and recoil during expiration, but the cartilage rings prevent it from collapsing and keep the airway patent despite the pressure changes that occur during breathing.

Answer 19

Elastic Elements

Question 20

Distinguised by permanent enlargement of the alveoli, acccompanied by destruction of the alveolar walls.

Invariably the lungs lose their elasticity.

Answer 20

Emphysema

Question 21

The respiratory changes in ________ do not alter blood O₂ and CO₂ levels significantly.

Hyperventilation is excessive ventilation, and is characterized by low ____ and alkalosis.

Answer 21

hyperpnea

P_CO2

Question 22

Cellular Respiration

Answer 22

The actual use of oxygen and production of carbon dioxide by tissue cells and the cornerstone of all energy-producing chemical reactions in the body.

Question 23

Quiet expiration depends more on lung ______ than on muscle _______.

Answer 23

Elasticity; Contraction

Question 24

Reduced Hemoglobin or Deoxyhemoglobin (HHb)

Answer 24

Hemoglobin that has released oxygen.

Question 25

Henry’s Law

Answer 25

States that when a gas is in contact with a liquid, the gas will dissolve in the liquid in proportion its partial pressure.

The greater the concentation of a particular gas in the gas phase, the more and the faster that gas will go into solution in the liquid.

Example - When PCO₂ in the pulmonary capillaries is higher than in the lungs, CO₂ diffuses out of the blood and enters the air in the alveoli.

Question 26

Irreversible decrease in thea bility ro force air out of the lungs.

Answer 26

Chronic Obstructive Pulmonary Diseases (COPD)

Question 27

The nearly complete saturation of Hb in arterial blood explains why breathing deeply _____ both the alveolar and arterial blood P_O2 but causes very little ______ in the O₂ saturation of hemoglobin.

Answer 27

Increase; Increase

Question 28

Smoking inhibits and ultimately destroys _____.

Answer 28

Ciliia.

Ciliary activity, coughing is the only way to prevent mucus from accumulating in the lungs.

When someone stops stmoking, cilary funcitonusually recovers within a few weks, and the morning “smoker’s cough” subsides.

Question 29

Because of the strong adhesive force between the parietal and visceral pleurae…

Answer 29

…pleural fluid secures the pleuae together the same way a drop of water holds two glasses slides together.

Pleural fluid in the pleural cavity must remain minimal to maintain a negative P_ip. The pleural fluid is actively pumped out of the pleual cavity into the lymphatics continously.

Question 30

Pneumothorax

Answer 30

The presence of air in the pleural cavity.

Reversed by drawing air out of the intrapleural space with chest tubes

Allows the pleurae to heal and the lung to reinflate and resume normal function.

Question 31

Changes in Intrapulmonary and Intrapleural Pressures During Inspiration and Expiration

Answer 31

Question 32

Inspiration

Answer 32

The period when air flows into the lungs.

Question 33

The most common kind of sleep apnea and is caused by collapse of the upper airway.

Answer 33

Obstructive sleep apnea

Question 34

The two lungs differ in size and shape beacsue the apex of the hart is slightly to the left of the median plane. The left lung is smaller than the right, and the ____ _____ - a concavity in its medial aspecit - is molded to and accomodates the heart.

Answer 34

Cardiac Notch

Question 35

An increase in the rate and depth of breahting that exceeds the body’s need tor remove CO2.

Answer 35

Hyperventilation

Low CO2 levels in the blood (hypocapnia) constrict cerebral blood vessels.This reduces brain perfusion, producing cerebral ischemia that causes dizziness and involuntary muscle spasms (tetany) int he hands and face caused by blood Ca²⁺ levels falling as pH rises.

Question 36

Three major types of cells are found in the alveoli:

Answer 36

1. Type 1 Alveolar Cells - squamous epithelial cells that form the major part of the alveolar walls.
2. Type II Alveolar Cells - cubodial epithelial cells that are scattered among the type 1 cells.

Secrete a fluid containing a detergent-like substance called surfactant that coats the gas-exposed alveolar surfaces. Secrete a number of antimicrobial proteins that are important elements of innate immunity.

3. Alveolar macrophages - crawl freely along the interanl alveolar surfaces consuming bacteria, dust and other debris.

Question 37

Inhaled irritants lead to chonic prdocution of excessive mucus.

The mucosae of the lower respiratory passageways become inflamed and fibrosed.

Answer 37

Chronic Bronchitis

Question 38

Defintied by the presence of thin-walled air sacs called alveloi, the respiratory zone beings as the termial broncioles feed into _____ ______ within the lung.

Answer 38

Respiratory bronchioles

Protruding from these smalles bronciles are scattered alveoli.

Question 39

Anatomical Dead Space

Answer 39

Does not contribute to the gas exchange in the alveoli.

Typically about 150 ml out of the TV of 500 ml; only 350ml of TV is used in alveolar ventilation.

Question 40

Our voluntary hold of our breath is limited, however, because the brain stem respiratory centers automatically reinitiate breathng when the blood concentration of ____ reaches critical levels.

Answer 40

CO₂

Question 41

COPD is treated with:

Answer 41

Inhaled bronchodilators and corticosteroids.

Severe dyspnea and hypoxia mandate oxgen use, but oxygen must be administered with care. Oxgen can elevated the P_CO2 (lower pH) to life-threenting levels.

Question 42

Pharynx

Answer 42

Question 43

Expiration

Answer 43

The period when gases exit the lungs.

Question 44

Respiratory Zone

Answer 44

Actual site of gas exahnce is composed of the respiratory broncioles, avelolar ducts, and alveoli, all microscopic events.

Question 45

Mucosa

Answer 45

Has the asame goblet cell-containg pseduostratified epithelium that occurs through most of the respiratory track.

Cilia continioually propel debris-laden mucus thoward the pahrynx.

Epithelium rest on a fairly thick lamina propria that has a rich supply of elastic fibers.

Question 46

Indicated by reduced arterial P_O2. Possible causes include disordered or abnormal ventilation-perfusion coupling, pulmonary diesease that impair ventilatio, and breathing air containing scant amounts of O_2.

Answer 46

Hypoxemic Hypoxia

Question 47

Oxygen Toxicity

Answer 47

Develops rapidly when P_O2 concentrations are greater than 2.5-3 atm. Excessively high O2 concentrations generate huge amounts of harmful free radicals, resulting in profound CNS disturbances, coma and death.

Question 48

Pharyngeal Tonsil

Answer 48

Traps and destroys pathogens entering the nasopharynx in air.

Question 49

Haldane Effect

Answer 49

The lower the P_O2 and the lower the Hb saturation with oxygen, the more CO₂ that the blood can carry.

This reflects the greater ability of HHb to form carbaminohemoglobin and to buffer H^{<span>+</span>} by combining with it.

Encourages CO₂ exchange in both the tissues and the lungs. In the pulmonary circulation, this is reversed - uptake of O₂ facilitates the release of CO₂.

Question 50

The pharynx is divided into three regions:

Answer 50

The nasopharynx, the oropharynx and the laryngopharynx.

Question 51

When inspiratory neurons fire, a burst of impuses travel along the _____ and _______ _______ to excite the diaphragm and external intercostal muscles.

As a result, the thorax expands and air rushes into the lungs.

As the expiratory neruons fire, the output stops, and expiration occur as the inspiratory muscles relax and the lungs recoil.

Answer 51

Phrenic; Intercostal Nerves

Question 52

At the tips of the bronchial tree, ________ zone structures give way to ________ zone structures.

Answer 52

Conducting; Respiratory

Question 53

Two significant features of Alveoli:

Answer 53

1. Surrounded by fine elsastic fibers of the same type that surround the elastic fibers of the same type that surround the entire broncial tree.
2. Open alveolar pores connecting adjacent alveoli allow airpressure throughout the lung to be equalized and provide alternate air routes to any alveoli whose bronci have collapsed due to disease.

REVIEW TABLE 21.2 on Page 729.

Question 54

The rate at which Hb reversibly bind or releases O2 is regulated by:

Answer 54

PO2

Temperature

Blood pH

P_CO2

Blood concentration of organic chemical called BPG.

Question 55

On the mediastinal surface of each lung is an identation, the _____, through which pulmonary and systemic blood vessels, bronci, lympathic vessels, and nerves enter and leave the lungs.

Answer 55

Hilum

Question 56

Respiratory Capacities (4)

Answer 56

Inspiratory

Functonal Residual

Vital

Total Lung

Always consist of (2) or more lung volumes.

Question 57

The inflation reflex in the _____ _____ and conducting passages in the lungs contain numerous stretch receptors that are vigorously stimulated when the lungs are inflated.

These receptors signal the _____ _____ _____ via afferent fibers of the vagus nerves sending inhibitory impules that end inspiration and allow expiration to occur.

Answer 57

Visceral Pleurae

Medullary Respiratory Centers

Question 58

Loudness of the voice depends on the force with which the airstream rushes across the vocal folds.

Answer 58

The greater the force, the stronger the virabation and the louder the sound.

The vocal folds do not move at all when we whisper, but they vibrate vigorously when we yell.

The muscles of the chcest, abomen and back provide the power for the airstream.

Question 59

Inspiratory Reserve Volume

Answer 59

The amount of air that can be inspired forcibly beyond the tidal volume (2100 to 3200 ml).

Question 60

Atelectasis

Answer 60

Lung collapse

Occurs when a brionchiole becomes plugged and the associated alveoli then absorb all of the air and collapse.

Can also occur in a chest wound or a rupture of the visceral pleura, which allows air from the respiratory tract to enter the pleural cavity.

Question 61

Henry’s Law

Answer 61

C = KP_gas

C = Solubility of a gas at fixed temperature in a particular solvent (M, mL gas/L)

K = Henry’s law constant (M/atm)

P_gas = Partial pressure of gas (atm)

When a liquid’s temperature rises, gas solubility decreases.

Question 62

All of these factors influence Hb saturation by modifying hemoglobin’s 3-D structure, thereby changing the affinity of O₂.

Answer 62

Increase in:

Temperature, P_O2, H⁺, or BPG

Levels in the blood lower’s Hb’s affinity for O₂, enhancing oxygen unloading from the blood.

Question 63

Alveolar Ventilation (AVR)

Answer 63

Takes into account the volume of air wasted in the dead space and measures the flow of fresh gases in and out of the alveoli during a particular time interval.

AVR = Frequency x (TV - Dead Space)

= 12 Breaths Per Minute x (500ml - 150 ml)

= 4200 ml/minute

Because deads space is constant, increasing the volume of each inspiration (breathing depth) enhances AVR and gas exhange mor ethan raise the respiratory rate).

AVR drops dramatically during rapid shallow breathing because mos to fthe inspired air never reaches the exchange sites.

Question 64

The normal respiratory rate and rhythm is called….

Answer 64

Eupnea.

Question 65

Dalton’s law of partial pressures

Answer 65

The total pressure exered by a mixture of gases is the sum of the pressures exerted by each gas.

Partial Pressure - is directly proportional to the percentage of that gas in the gas mixture.

At high altitudes, partial pressures decline in direct proportion to the decrease in atmospheric pressure. The same occurs below sea level - eveything stays proportional.

Question 66

The nasal cavity is lined with two types of mucous membrane (2):

Answer 66

1. Olfactory mucosa - lines the slitlike superior region of the nasal cavity and contains smell receptors in its olfactory epithelium
2. Respiratory mucosa - lines most of the nasal cavity. It is a psuedostratified ciliated columnar epithelium, containng scattered goblet cells that ress on the lamina propria richly supplied with seromucous nasal glands.

Question 67

Exerrnatl Respiration

Answer 67

O₂ diffueses from the lungs to the blood.

CO₂ diffueses from the blood to the lungs.

Question 68

Systemic venous blood that is to be oxygenated in the lungs is delivered by the ______ ______, which lie anterior to the main bronchi.

Branch profusely along with the bronchi and finally feed the ______ ______ ______ surroding the alveoli.

The _______ _______ convery the freshly oxygenated blood from the respiratory zone of the lungs to the heart.

Answer 68

Pulmonary Arteries

Pulmonary Capillary Networks

Pulmonary Veins

*Tributaries course back to the hilum both with the corresponding bonci and in the connectvie tussue septa seprating the bronchopulmonary segments.

Question 69

Vocal Ligaments

Answer 69

Attach the arytenoid cartilages to the thyroid cartilages.

Composed of elastic fibers.

Form the core of mucosal folds called the vocal chords, which appear pearly white because they lack blood vessels.

Vibrate producing sounds as air ruses up from the lungs.

Question 70

The most common cases of lung cancer:

Answer 70

1. Adenocarcinoma (20%)
2. Squamous cell carcinoma (40%)
3. Small cell carcinoma (15%)

Question 71

As arterial blood flows through systemic capillaries, it releases about 5 ml of O₂ per 100 ml of blood, yielding an Hb saturation of ____ % and an O₂ content of _____ % volume in venous blood.

This means that substantial amounts of O₂ are normally still available in venous blood (the venous reserve), which can be used if needed

Answer 71

75; 15

15/20 = 75%

Question 72

Inhibit cell growth and division, so the inactivation of these genes is a factor in uncontrolled cell growth.

Answer 72

Tumor suppressor genes

Question 73

The reclamation process minimizes:

Answer 73

The amount of moisture and heat lost from the body though breathing, helping us to survivve in dry and cold climates.

Question 74

The Larynx (3) Functions:

Answer 74

1. Provdie a patent (open) airway.
2. Actas a switching mechanism to route air and food into the proper channels.
3. Voice production (because it houses the vocal folds (vocal cords).

Question 75

Intrapleural Pressure (P_ip)

Answer 75

The pressure in the pleural cavity.

Fluctuates with breathing phases, but is always about 4 mm Hg lesss than P_pul.

P_ip is alwyas negative relative to P_pul

Question 76

Infant Respiratory Distress Syndrome (IRDS)

Answer 76

Alveoli must be completely reinflated during each inspiration, an effor tthat uses tremendous amounts of energy.

This is a a problemt faced by newborns.

A condition common in premature babies. Since fetal lugns do not produce adqueate amounts of surfactant until the last two months of development, babies born prematurely often are unable to keep their alveoli inflated between breaths.

Treated by sparing natural or syntheic surfactant into the newborn’s respiratory passageways.

Devices to keep alveoli open between breaths can be used.

Many survivors suffer from bronchopulmonary dysplasia, a chronic lung disease during childhood and beyond.

Question 77

Forced Vital Capacity (FVC)

Answer 77

Measures the amount of gas expelled when a subject takes a deep breathand then forcefully exhales maximally and as rapidly as possible.

Question 78

Unique type of hypoxemic hypoxia and a leading cause of death from fire.

Answer 78

Carbon Monoxide Poisioning

Hb’s affinity for CO is more than 200x greater than its affinity for O_2, CO outcompetes O₂ for heme binding sites.

Question 79

Nasopharynx

Answer 79

Posterior to the nasal cavity; Inferior to the sphenoid bone; Superior to the level of the soft palate.

Only serves as an air passageway.

During swallowing, the soft palate anduvula move supeiorly to close off the nasopharynx and prevents food from entering the nasal cavity.

Pseudostratified ciliated epithelium takes over the jobof propelling mucus where the nasal mucosa leaves off.

• Pharyngotympanic (auditory) tubes*, which drain the middle ear caviities and allow middle ear pressure to rqualize with atmospheric pressure, openinto the lateral walls of the nasopharynx.
• Tubal tonsil* helps protect the middle ear against infections likely to spread from the nasopharynx.

Question 80

Blood transports CO₂ from the tissue cells to the lungs in three forms:

Answer 80

1. Dissolved in Plasma - 7-10% - The smallest amount of CO₂ is transported simply dissolved in plasma.

2. Chemically bound to hemoglobin - just over 20% - Dissolved CO₂ is bound and carried in the RBC’s as carbaminohemoglobin.

CO₂ + Hb ⇔ HbCO₂

Carbon dioxide transport in RBCs does not compete with HbO₂ transport because CO₂ binds directly to the amin.o acids of globin (not the heme).

Carbon dioxide rapidly dissociates from the hemoglobin in the lungs where the P_CO2 of alveolar air is lower than that in blood (CO₂ leaves the pulmonary capillaries and enters into the alveoli through the respiratory membrane).

CO₂ readily binds with Hb in the tissues, where the P_CO2 is higher than that in blood.

HHb combines more readliy with CO₂ than HbO₂.

3. As bicarbonate ions in plasma - About 70% - The reactions that convert bicarbonate (HCO₃^-) for transport mostly occur inside RBCs.

When dissolved CO₂ diffuses into RBCs, it combines with H₂O, forming carbonic acid (H₂CO₃).

CO₂ + H₂O ⇔ H₂CO₃ ⇔ H⁺ + HCO₃^-

This reaction occurs in plasma, but due to carbonic anhydrase, it occurs 1000x faster in RBCs.

H⁺ and CO₂ bind to Hb, triggering the Bohr Effect (releasing O₂).

HCO₃^- moves quickly from the RBCS into the plasma, where it is carried to the lungs. Cl^- moves from the plasma in the RBCs (chloride shift) which occurs via facilitated diffusion through an RBC membrane protein.

In the lungs, the process is reversed.

Question 81

The nasal cavity is continuous posteriorly with the nasal portion of the pharynx through the _____ ______ _____, also called the choanae.

Answer 81

Posterior nasal apertures

Question 82

The lower respiratory system consists of:

Answer 82

Larynx

Trachea

Bronchi and branches

Lungs and alveoli

Question 83

A positive respiratory pressure is ______ than atmospheric pressure.

Answer 83

Higher

Question 84

2. Chemically bound to hemoglobin

Answer 84

Just over 20% - Dissolved CO2 is bound and carried in the RBC’s as carbaminohemoglobin.

CO2 + Hb ⇔ HbCO2

Carbon dioxide transport in RBCs does not compete with HbO2 transport because CO2 binds directly to the amin.o acids of globin (not the heme).

Carbon dioxide rapidly dissociates from the hemoglobin in the lungs where the PCO2 of alveolar air is lower than that in blood (CO2 leaves the pulmonary capillaries and enters into the alveoli through the respiratory membrane).

CO2 readily binds with Hb in the tissues, where the PCO2 is higher than that in blood.

HHb combines more readliy with CO2 than HbO2.

Question 85

Episodes of coughing, dyspnea, wheezing, and chest tightness - alone or in combinations.

Obstructive disorder that is marked by acute episodes followed by symptom-free periods - that is, the obstruction is reversible.

Active inflammation of the airways comes first. The inflammation is an immune response controlled by a subset of T lymphocytes that stimulate the production of IgE antibodies and recruit inflammatroy cells to the site.

Bronchodilators and inhaled corticosteriods.

Answer 85

Asthma

Question 86

Lung Compliance

Answer 86

Measure of the change in lung volume that occurs with agiven cahgne in transpulmonary pressure.

C₁ = (V_L2 - V_L1) / (P_Pul-P_ip)₂-P_Pul-P_ip)1

The more the lung expands for a given rise in transpulmonary pressure, the greater the compliance.

The higher the lung compliance the easier it is to expand the lungs at any given transpulmonary pressure.

Question 87

Many people mistake alveoli, site of gas exchange, with alveolar sacs, but they are not the same thing.

The alvelor sac is analogous to a bunch of grapes, and the alveloi ar the individual graps.

Answer 87

Question 88

Total Lung Capacity (TLC)

Answer 88

The sum of all lung volumes.

TLC = TV + IRV + ERV + RV

Question 89

Respiratory Volumes (4):

Answer 89

Tidal Volume

Inspiratory Volume

Reserve Volume

Residual Volume

Question 90

Bicarbonate Buffer System

Answer 90

If the H⁺ concentration in blood begins to rise, excess H⁺ is removed by combining with HCO₃^- (alkaline reserve - weak base) to from H₂CO₃ (weak acid).

If H⁺ concentration in the blood drops below desirable levels, H₂CO3 dissociates, releasing H⁺ and lowering pH again.

Question 91

The result from lactic acid levels in the blood during exercise results from the _____ ______.

Answer 91

Anaerobic respiration

Question 92

Lesions made in the superior region of the pontine respiratory center cause inspirations to become very prolonged.

Answer 92

Apneustic breathing

Question 93

Carina

Answer 93

The last tracheal cartilage is expanded, and a cartilage projects posteriorly from its inner face, marking th epoint whe the trachea branches into two main bronchi.

Highly sensitive, and violent coughin is triggered whena foreing object makes contact with it.

By the time incoming air reaches the end of the trachea, it is warm, cleased of most impuritis and saturaded with water vapor.

Question 94

Under normal conditions, declining P_O2 has only a slight effect on ventilation, mostly limited to enhancing the sensitivity of peripheral receptors (aortic and carotid) to increased P_CO2.

Arterial P_O2 must _____ substantially before O₂ levels become a major stimulus for increased ventilation.

Answer 94

Drop

There is a huge reservoir of O₂ bound to Hb, and Hb remains almost entirely saturated unless or until the P_O2 of alveolar gas and arterial blood falls below 60 mm Hg.

The brain stem centers then begin to suffer from O₂ starvation, and their activity is depressed at the same time, the peripheral chemoreceptors become excited and stimulate the respiratory centers to increase ventilation, even if P_CO2 is normal.

The peripheral chemoreceptor can maintain ventilation even though the brain stem centers are depressed by hypoxia.

Question 95

The high _____ content of mucus film humidifies incoming air.

Answer 95

water

Question 96

Three factors influence external respiration:

Answer 96

1. Partial pressure gradients and gas solubilities. P_O2 of deoxygenated blood int he pulmonary arteries is only 40 mm HG as opposed to P_O2 in the alveoli of 104 mm Hg. Equilibrium, which is 104 mm Hg on each side of the respiratory membrane, occurs in 0.25 seconds.

CO2 can diffuse in the opposite direction (pulmonary capillaries to the alveoli) much gentler partial pressure gradient of 5 mm Hg. This is the pulmonary capillary of 45 mm Hg to the alveoli of 40 mm Hg, until 40 mm Hg is on both sides of the respiratory membrane.

Equal amounts are exchanged becuase CO2 is 20x more soluble in plasma and alveolar fluid than O2.

2. Thickness and surface area of the respiratory membrane. The respiratory membrane is only 0.5 to 1 µm thick and gas exchange is very efficient. The greater the surface area of the respiratory membrane the more gas that can diffuse across it in a given time period.

3. Ventilation-perfusion coupling (matching alveolar ventiation with pulmonary blood perfusion). Ventilation is the amoutn of gas reaching the alveoli and perfusion is the blood flow in pulmonary capillaries.

P_O2 controls perfusion by changing arteriolar diameter.
P_CO2 controls ventilation by changing bronchiolar diameter.

Question 97

A _____ in body temperature raises the respiratory rate, while a drop in body temperature produces the opposite effects.

Answer 97

Rise

Sudden chilling (a dip in the North Atlantic Ocean in late October) can stop your breathing (apnea) - or at the very least, leave you gasping.

Question 98

In restrictive diseases, VC, TLC, FRC and RV ______ because lung expansion is limited.

Answer 98

Decline

Question 99

The nasal conchae and mucosa funtion during exhalaiton to:

Answer 99

Reclaim heat and moisture.

Exhalation the cooled conchae precipitate moisture and extract heat from the humid air flowing over them.

Question 100

Cancer-causing genes and inactivate tumor suppressing genes.

Answer 100

Oncogenes

Question 101

Boyle’s Law

Answer 101

P1V1 = P2V2

At a constant temperature, the pressure of a gas varies inversely with its volume.

Gases always fill their container.

Question 102

High-altitude conditions result in _____ than normal Hb saturation levels because less O₂ is available to be loaded.

Answer 102

Lower

Question 103

Common disorder that is characterized by the temporary cessation of breathing during sleep.

Answer 103

Sleep Apnea

Question 104

The nasal concahe and nasal mucosa function during inhalation to:

Answer 104

Filter, heat and moisten the air.

Inspired air cools the conchae.

Question 105

While rising blood CO2 levels act as the initial stimulus, it is rising levels of ____ generated within the brain that prod the central chemoreceptors into increased activity.

Answer 105

H+

Question 106

Effect of P_CO2, H⁺, or BPG on the Oxygen Dissociation Curve

Answer 106

Question 107

Smoking paralyzes _____ that clear mucus from the airways, allowing irritants and pathogens to accumulate. The “cocktail” of free radicals and other carcinogens in tobacco smoke eventually translates into lung cancer.

Answer 107

Cilia

Question 108

Control of breathing during rest is aimed primarily at regulating the ____ concentration in the bran.

Answer 108

H+

Question 109

Changes in Thoracic Volume and Sequence of Events During Inspiration

Answer 109

Question 110

The gases in inhaled air swirl through the twists and turns deflecting heavier, nongaseous particles onto the mucus-coated surfaces, were they become trapped.

Answer 110

As a result, few partickesl larger tha. 6 µm make it pas the nasal cavity.

Question 111

The epithelial cells of the respiratory mucosa also secrete ______, natual antibiotics that help kill invading microbes.

Answer 111

Defensins

Question 112

Intrapulmonary Pressure (P_pul)

Answer 112

The pressure in the alveoli.

Rises and falls with the phases of breathing, but it is always equalizes with the atomospheric pressure eventually.

Question 113

Two forces act to pull the lungs (visceral pleura) away from the thorax wall (parietal pleura) and cause the lungs to collapes:

Answer 113

1. The lungs natural tendency to recoil.
2. The surface tension of the alveolar fluid.

*These forces are opposed by the natural elasticity of the chest wall.

Question 114

The external surfaces of alveoli are densely covered with a “cobweb” of pulmonary capillaries. Together the capillary and alvelolar walls and their fused basement membranes form the _______ _______, a 0.5 µm-thick-blood air barrier that has blood flowing pass on one side and gas on the other.

Answer 114

Respiratory membrane

Gas exchanges occur readily by simple diffusiona cross the respiratory membrane - O2 passes from the alveolus into the blood, and CO2 leveas the blood to enter the gas-filled alveolus.

Question 115

Ventilation-Perfusion Coupling

Answer 115

Question 116

More than 80% of patients have a history of smoking.

Dyspnea

Coughing and frequent pulmonary infections.

Most COPD patientds develop respiratoy failure manifested as hypoventilation.

Answer 116

COPD

Question 117

In contrast to the Pulmoonary Circulation, _____ ______ provide oxygenated systemic blood to lung tissue.

The bronchiole arteries arise from the aorta, enter the lugns at the hikum, and hen run along the branching bronchi. They provide a _____ pressure, _____ volume supply of oxygenated blood to all lung tissues except ______.

Answer 117

Bronchial Arteries

High, Low

Alveoli

Question 118

The lobar bronci branch into third-order _____ (tertiary) bronchi, which divide repeatedly into smaller and smaller bronci (4th, 5th-order, etc…)

Answer 118

Segmental

Question 119

Occurs when the body cells are unable to use O₂ even though adequate amoutns are delivered. Metabolic poisions, such as cyanide, can cause _______ ________.

Answer 119

Histotoxic Hypoxia

Question 120

Clustered neurons in two areas of the medulla oblongata appear to be critically important in respiration:

Answer 120

1. Ventral respiratory group (VRG)
2. Dorsal respiratory group (DRG)

Question 121

Chemoreceptors are found in two major body locations:

Answer 121

1. Central Chemoreceptors - located throughout the brain stem, including the ventrolateral medulla.

2. Peripheral Chemoreceptors - located in the aortic arch and carotid arteries.

Question 122

Anaerobic respiration is not a lack of respiratory function because alveolar ventilation and pulmonary perfusion are as well matched ruing exericse as during rest (hemoglobin remains fully saturated).

It refletcs ____ ____ limitations or inability of the skeletal musclces in further to further increase their oxygen consumption.

Answer 122

Cardiac Output

Question 123

Nasal Vestibule

Answer 123

the part of the nasal cavity just supeiror toeach nostril and is liined with skin containing sebaceous and sweat glands and numours hair follicles.

Question 124

Features of the external nose:

Answer 124

Root (Area between the eyebrows) Bridge Dorsum Nasi (Anterior margin) Apex (Tip of the nose) Nostrils (External openings of the nose) bound laterally by the flared alae.

Question 125

Transport of Respiratiory Gases

Answer 125

The cardiovascular system transports gaes using blood as the transporting fluid.

O2 is transported from the lugns to the tissue cells of the body.

CO2 is transported from the tissues cells to the lungs.

Question 126

The upper respiratory system consists of all the structures from the ____ to the ____.

Answer 126

Nose and nasal cavity

Paranasal sinuses

Pharynx

Question 127

A zero respiratory pressure is ______ to atomospheric pressure.

Answer 127

Zero

Question 128

Leading cause of cancer death for both men and women in North America.

90% of cases result from smoking.

Cure rate is notoriously low, with most people dying within one year of diagnosis. The five year survival rate is 16%

Metasized quickly and rapidly; not diagnosed until advanced.

Activated oncogenes.

Ordinarily nasal hairs, sticky mucus and cilia do a fine job of protecting the lungs from chemical and biological irritants, but when a perosn smokes, these defesnes are overwhelmed and eventually stop functioning.

Answer 128

Lung Cancer

Question 129

Ventral Respiratory Center (VRG)

Answer 129

• Rhythm-generating integrative center
• Contains groups of neurons that fire during inspiration and others that fire during expiration in a dance of mutual inhibition.

Question 130

Laryngitis

Answer 130

Inflammation of the vocal folds to swell, interfering with their vibration.

Changes in vocal tone, causing hoarsness, or in sever cases limiting us to a whisper.

Often caused by viral infections, but may also be due to overusing th voice, very dry air, bacterial infections, tumors on the vocal folds, or inhalation of irritating chemicals.

Question 131

During voluntary control, the ______ _____ ______ sends signals to the motor neurons that stimulate the respiratory muscles bypassing the medullary centers.

Answer 131

Cerebral Motor Cortex

Question 132

The pleurae also help divide the thoractic cavity into three chambers:

Answer 132

The central mediastinum and the two lateral pleural comparntments (each containing a lung).

Helps from ograns interferring with one another.

Also, limits the spread of local infections.

Question 133

Noses vary a great deal is size and shape, largely because of the differences in ______ ______.

Answer 133

Nasal Cartilages

Question 134

1. Dissolved in Plasma

Answer 134

About 7-10% - The smallest amount of CO2 is transported simply dissolved in plasma.

Question 135

Influence of P_O2 on Hemoglobin Saturation

The oxygen-hemoglobin dissociation curve shows how local P_O2 controls

Answer 135

oxygen loading and unloading from hemoglobin.

Question 136

The infectious disease caused by bacterium by coughing and primarily enters the body in inhaled air.

Mostly affects the lungs but can be spread through the lymphatics to other organs.

1/3 of the world’s population is infected.

Most people never develop active TB because a massive inflammatory response usually contains the primary infection in fibrous, or calcified, nodules (tubercles) in the lungs.

The bacteria may survive in a person’s lungs and when the immune system is weakened it may break out and become active.

Symptoms include fever, night sweats, weigth loss, racking cough, and coughing up blood.

Treatment needs to be complete.

Answer 136

Tuberculosis (TB)

Question 137

The walls of the alveoli are composed primarily of single layer of squamous epithelial cells, called ____ ____ ____ ____, surronded by a flimsy basement membrane.

Answer 137

Type 1 Alveolar Cells

A sheet of tissue paper is 15x thicker!

Question 138

P_O2 are a good index of lung function and when arteriol P_O2 is signifcantly _____ than aveolar P_O2 some degree of respiratory impairment exists.

Answer 138

Less

Question 139

The pulmonary circuit is a ____ pressure, ____ volume circulation.

All the body’s blood passes through the lungs about ____ each minute, the lung capillary endothelium i an ideal locaiton for enzymes that cat on materisl in the blood.

Examples include ______ ______ ______, which activates an important blood pressure hormone, and enzymes that inactive ertani prostaglandins

Answer 139

Low; High

Once

Angiotension Converting Enzyme

Question 140

The alveolar ducts lead into terminal clusters of alveoli called _____ _____.

Answer 140

Alveolar sacs

Question 141

Respiratory Volumes and Capacities

Answer 141

Question 142

Glottis

Answer 142

The medial opening between the vocal chords through which air passes.

Question 143

Inhaled irritants activate a reflex of the parasympathetic divison of the nervous system that causes constriction of the bronchioles and dramatically reduces air passage.

Answer 143

During an asthma attack, histamine and other inflammatory chemicals can cause such strong broncoconstriction that pulmonary ventailation almost ocmpleelty stops, regardless of the pressure gradient.

Conversly, epinephrine relesed during sympathetic nevous system activation or adminsitered as a drug dilates bronchioles and reduces airway resistance.

Local accumulation of mucus, infectious materials, or solid tumors in the passageways are important sources of airway resistnace in those with respiratory disease.

When bronchioles are severly constricted or obstructed, even the most extreme respiratory efforts cannot restore ventialation to life-sustaning levels.

Question 144

Each lobe contains a number of pyramind - shaped _______ _______ seperated from one another by connective tissue septa.

Answer 144

Bronchopulmonary Segments

The right lung has 10 segments and the left lung has 8-10 segments.

Each segemnt is served by its own artery and vein and recieves air from an indiviual segmental (tertiary) bronchus.

Question 145

Under normal conditions, blood PO2 affects breathing only indirectly.

Answer 145

It influences peripheral chemoreceptor sensitivity to changes in P_CO2. Low P_O2 augments P_CO2 effects and high P_O2 levels diminish the effectiveness of CO₂ stimulation.

Question 146

Larynx

Answer 146

Voice box.

Superiorly attaches to thehyoid bone and opens into the laryngopharynx. It is inferiorly continuous with the trachea.

Question 147

The respiratory bronchioles lead into winding _____ ______, whose walls consist of diffusely arranged rings of smoth muscle cells, connective tissue fibers, and outpocketing alveoli.

Answer 147

Alveolar ducts

Question 148

The skeletal framework is fashioned by the ____ l and ____ bones superiorly, the _______ bones laterally, and flexible plates of ______ cartilage inferiorly.

Answer 148

Nasal; Frontal, Maxillary, Hyaline

Question 149

Three neural factors for the abrupt increase in ventilation during exercise:

Answer 149

1. Psychological stimuli (conscious anticipation of exercise)
2. Simultaneous cortical motor activities of skeletabl muscles and respiration centers.
3. Excitatory input reaching respiratory centers from proprioceptors in moving mucles, tendons and joints.

Question 150

Each broncs runs ______ in the ______ before plunging into the medial depression (hilium) of its lung.

Answer 150

Obliquely, Mediastinum

Question 151

Spirometry

Answer 151

Cannot provide a specific diagnoses, but it can distinguish between obstructive pulmonary disease involving increased airway resistance and restrictive diseases involving involving reduced total lung capacity.

Question 152

Thought to be more of a protective response than a normal regulatory mechanism.

Answer 152

Inflation (Hering-Breuer) Reflex

Question 153

Paranasal Sinues

Answer 153

Surround the nasal cavity in a ring.

Located in the frontal, sphenoid, ehtmoid and maxillary bones.

Lightens the skull.

Help warm and moisten the air.

The mucus they produce ulitamtely flows into the nasal cavity, and the suctioning effect created by blowing the nose helps drain the sinuses.

Question 154

Terminal bronchioles

Answer 154

Less than 0.5 mm in diameter.

Question 155

The ciliated cells of the respiratory mucosa create a gentle current that moves the sheet of contaminated mucus posteriorly toward the throat, where it is ______ and ______.

Answer 155

Swallowed; digested.

Question 156

Surface Tension (2)

Answer 156

1. Draws the liquid molecules closer together and reduces their contact iwth the dissmilar gas molecules.
2. Resists any force that tends to increase the surface area of the liquid.

Question 157

Transpulmonary Pressure

Answer 157

The difference between the intrapulmonary pressure and the intrapleural pressure.

P_ip - P_pul

This pressure keeps the air spaces of the lungs open, or keeps the lungs from collapsing.

The size of the transpulmonary pressure determines thesize of the lungs at any time (directly proportional).

Any condition where P_ip = P_pul causes immediate lung collapse.

Question 158

An inadequate blood supply to an organ or part of the body, especially the heart muscles.

Answer 158

Ischemia

Question 159

Nonrespiratory air movements

Answer 159

Occur whenever you sneee, cough, cry, laugh, hiccup or yawn.

Question 160

The peripheral chemoreceptors - found in the aortic arch and carotid arteries - contain cells sensitive to aerterial O_2.

The main oxygen sensors are in the _____ _____.

Answer 160

Carotid Bodies

Question 161

The most important factors in influence breathing rate and depth are:

Answer 161

Changing levels of CO₂, O₂, and H⁺ in arterial blood.

Question 162

Effect of Temperature on the Oxygen Dissociation Curve

Answer 162

Question 163

Air Resistance is insignificant for two reasons:

Answer 163

1. Airway diameters in the first part of the conducting zone are huge, relative to the low viscosity of iar.
2. As the airways get smaller, there are progressively more branches. As a result, the cross sectional area is huge.

Greatest resitance to gas flow is in the medium-sized bronci.

Question 164

Laryngopharynx

Answer 164

Serves as a passageway for food and inhaled air.

Lined with stratified squamous epithelium.

Lies directly posterior to the larynx, where respiratory and digestive pathways diverege, and extends into the inferior edge of the cricoid cartilage.

Continuous with the esophogus.

Esphogus conducts food and fluids ot the stomahcl air enters thelarynx anteriorly.

During swallowing, food has the “right of way” and air passage temporarily stops.

Question 165

Oropharynx

Answer 165

Lies posterior to the oral cavity and is continuous with it through an archway called isthmus of the fauces.

Both swallowe food and inhaled air pass through it.

Epithelium changes from pseudostratified columnar to a more protective stratified squamous epithelium to accomade increased friction and chemical trauma accompanying food passage.

The palantine tonsil lie embedded int he lateral walls of the oropharyngela mucosa just posterior to the oral cavity.

The lingual tonsil covers the psoterior surface of the tongue.

Question 166

The smallest subdivision of the lung visible with the naked eye are the ______.

Answer 166

Lobules

Appear at the lung surace as hexagons ranging rom the size of a pencil eraser to the size of a penny.

A larger bronchiole and its brancehs serve each lobule.

In most city dwellersand in smokers, the connective tissue that seperates the individual lobules is blackened with carbon.

Question 167

The lungs consist of largely of air spaces.

The balalance of lung tissue, or its ______, is mostly elastic connective tissue.

Answer 167

Stroma

As a result the lungs are elastic organs togherer weigh just over 1kg.

Question 168

The air passageways in the lungs branch about ___ times.

Answer 168

23

Question 169

Layers of the Trachea

Answer 169

The mucosa, the submucosa, the adventitia - plus the layrer of hyaline cartilage.

Question 170

Hypoxia

Answer 170

Inadequate oxygen delivery to the body tissues.

Question 171

Tissue Composition of the Tracheal Wall

Answer 171

Question 172

Oxyhemoglobin (HbO₂)

Answer 172

Hemoglobin-oxygen combination

Question 173

Each cone shaped lung is surrounded by _____ and connected to the _____ by vascular and broncial attachments collectively called the lung _____.

Answer 173

Pleurae; Mediastinum

Root

Question 174

Bronchioles

Answer 174

Passages smaller tham 1mm in diameter.

Question 175

The unsupported posterior portion is the muscular _____ _____.

Answer 175

Soft Palate

Question 176

Internal Respiration

Answer 176

Involves capillary gas exchange in the body tissues (systemic circulation).

O2 diffuses from the blood into the tissue cells and CO2 diffuses from the CO2 into the blood.

Venous blood draining the tissue capillary beds and returning to the heart has a P_O2 of 40 mm Hg and a P_Co2 of 45 mm Hg

Question 177

During breathing, air enters the nasal cavity by passing through the _____ or ______.

Answer 177

Nostrils, nares

Question 178

The groove inferior to each concha is a _____ _____.

Answer 178

Nasal meatus.

Question 179

Respiratory Volumes and Capacities

Answer 179

Question 180

The skin covering the nose anterior and lateral aspects is ____ and contains many _____ glands.

Answer 180

Thin, sebaceous

Question 181

Expiratory Reserve Volume (ERV)

Answer 181

The amount of air - normally 1000 to 1200 ml - that can be expelled form the lugns after a normal tidal volume expiration.

Question 182

The framework of the larynx is an intricate arrangelment of nine cartilages connected by membranes and ligaments. Except for the ______, all laryngeal cartilages are hyaline cartilage.

Answer 182

Epiglottis

Question 183

Inspiratory Muscle Activation

Answer 183

1. Action of the diapraghm - When the dome-shaped diapraghm contracts, it moves inferiorly and flattens out. The superior-inferior dimension (height) of the thoracic cavity increases.

2. Action of the intercostal muscles - when they contract, they lift the rib cage and pull the sternum superiorly.

This is enough to increase the thoracic volume by 500ml - the usual volume that enters the lungs during a normal quiet inspiration. The diaphragm is far more imporatnt in producing these volume changes that lead to normal quiet inspiration.

As thoracic dimensions increase during inspiration, the lungs are stretched and the intrapulmonary volume increases.

P_pul drops about 1 mm Hg relative to P_atm. Anytime Ppul < P_atm, air rushes into the lugns along the pressure gradient.

Inspiration ends when Ppul = P_atm. During this period, P_ip declines to about -6 mm Hg relative to P_atm.

Question 184

In obstructive diseases, TLC, FRC and RV may _______ because the lungs hyperinflate.

Answer 184

Increase

Question 185

Total Dead Space

Answer 185

Anatomical Dead Space + Alveolar Dead Space

Question 186

The nose (5):

Answer 186

1. Provides an airway for respiration. 2. Moistens and warms entering air. 3. Filters and cleans inspired air. 4. Serves as a resonating chamber for speech. 5. Houses the olfactory (smell) receptors.

Question 187

At high altitudes, Hb’s affinity for O₂ is reduces because ____ concentrations increase. This releases more O₂ to the tissues during each circulatory round.

Answer 187

BPG

Question 188

Internal Respiration

Answer 188

Oxygen leaves the blood and enters tissue cells, carbon dioxide leaves the tissue cells and enters the blood.

Question 189

The respiratory system includes:

Answer 189

The nose

The paranasal sinuses

The pharynx

The larynx

The trachea

The bronchi and their smaller branches

The lungs and tiny air sacs called the alveoli

Question 190

Inspiratory Capacity (IC):

Answer 190

The toal amount of air that can be inspired after a normal tidal volume expiration.

IC = TV + IRV

Question 191

Pleurisy

Answer 191

Inflammation of the Pleurae

Often from Pneumonia

Become rough, rsulting in frcitona nd stabbing pain with each breath.

With progression, more fluid accumulates, which relieves pain, but exerts pressure on the lungs and makes breathing movement hard.

Other fluids may include blood, blood filtrate - pleural effusion.

Question 192

P_O2 measurements indicate only the amount of O₂ dissolved in _____, not the amount bound to ______. P_O2 are a good index of lung function.

Answer 192

Plasma; Hemoglobin.

Question 193

Conducting Zone

Answer 193

Consists of all the respiratory passageways from the nose to the respiratory bronchioles.

Provide fairly rigid conduits for air to treach the gas exchange sites.

Cleanse, humidfy and warm incoming air.

As a result, air reaching the lungs has fewer irritants (dust, bacteria, etc) than when it entered the body, and it is warm and damp, like the air of the tropics.

Question 194

Sensors responding to chemical fluctuations

Answer 194

Chemoreceptors

Question 195

Pharynx

Answer 195

Commonly referred to as the throat.

Tunnel-shaped.

Connects the nasal cavity and mouth superiorly to the larynx and esophagus inferiorly.

Extends from the base of the skull to the level of the sixth cervical vertebra (C6).

Composed of skeletal muscle throughout its length.

Cellular composition changes from one pharygneal region to another.

Question 196

The structures of the nose is divided into the ______ nose and the ______ ______ ______.

Answer 196

External; Internal nasal cavity.

Question 197

Located dorsally near the root of cranial nerve IX.

Answer 197

Dorsal Respiratory Group (DRG)

Integrates Peripheral sensory input and modifies the rhythms generated by the VRG.

Question 198

The left lung is subdivided into superior and inferior lobes by the ______ fissure, where as the right lung is partioned into superior, middel and inferior lobes by the _____ and _____ fissure.

Answer 198

Oblique

Oblique; Horizontal

Question 199

Nonelastic sources of resistance

Answer 199

Friction or drag encountered in the respiratory passages.

Question 200

Vibrissae

Answer 200

The hairs that filter corase partcles (dust, pollen) from inspired air.

Question 201

The pleura produce ____ _____, which fills the slitlike pleural cavity between them.

Answer 201

Pleural Fluid

The lubricating secretion allos the lungs to glide easily over the thorax wall during our breathing movements.

Lungs cling tightly to the thorax wall and expand and recoil passively as the volume of the thoracacic cavity alternatively increases and decreases during breathing.

Question 202

Lung Compliance depends on (2):

Answer 202

1. Distensibility of Lung Tissue
2. Alveolar Surface Tension

Healthy lungs usually have a high compliance.

Question 203

After the first O2 molecule binds to iron, the Hb molecule changes shape. As a result, it more readily takes up two more O2 molecules, and uptake of the fourth is even more facilitated.

Answer 203

When 1, 2, or 3 oxygen molecules are bound, a hemoglobin moelcule is partially saturated. When all 4 of its heme groups are bound to O_2, the hemoglobin is fully saturated.

Unloading of one oxygen molecule enhances the unlaoding of the next, and so on. The affinity of hemoglobin for oxygen changes with the extent of oxygen saturation, and both loading and unloading of oxygen are very efficient.

Question 204

During hypercapnia, CO₂ accumulates in the brain. As CO₂ accumulates, it is hydrate to form _____ _____. The acid dissociates, H⁺, and the pH drops. This is the same reaction that occurs when CO₂ enters RBCs.

Answer 204

Carbonic Acid

Question 205

The major function of _______ is to supply the body with oxygen and dispose of carbon dioxide

Answer 205

Respiratory System

Question 206

Working muscles consume tremndous amounts of ____ and produce large amoutns of _____, so ventilation can increase 10-20x during vigorous exercise.

Answer 206

O_2; CO₂

Question 207

The respiratory system as a whole consists of two zones:

Answer 207

1. Respiratory Zone
2. Conducting Zone

Question 208

Reflects poor O₂ delivery resulting from too few RBS or from RBCs that contain abnormal or too little Hb.

Answer 208

Anemic Hypoxia

Question 209

During hypoxia, VRG networks generate gasping.

Respiration stops when a certain cluster of VRG neurons is completely surpessed, as by an overdose of ______ or ______.

Answer 209

Morphine; Alcohol

Question 210

When blood O₂ levels decline, the kidney’s produce more erythropoietin, which stimulates bone marrow production of RBCs. This provides long-term compensation for living at ____ altitudes.

Answer 210

High

Question 211

Influence of Arterial pH

Answer 211

Changes in arterial pH can modify the respiratory rate and rhythm even when CO₂ and O₂ levels are normal.

H+ does not cross the blood brain barrier, the increased ventilation that occurs in response tofall arterial pH is mediated throgh the peripheral chemoreceptors.

Changes in CO2 and H+ are distinct stimuli.

A drop in blood pH may be a result from retention of CO₂, but it may also result from metabolic causes, such as accumulation of lactic acid during exercise or of fatty acid metabolites (ketone bodies) in patients with poorly controlled diabetes mellitus.

The respiratory system tries to control decreases in pH by increasing the respiratory rate and depth to eliminate CO₂ (and carbonic acid) from the blood.

Question 212

External Respiration

Answer 212

Oxygen enters the blood and carbon dioxide leave the blood by diffusion.

Question 213

The ______ from a thin, dobule-latered serosa.

The layer called the _____ ______ voers the thoracic wall and superior face of the diaphragm.

It continues around the heart and between the lungs, forming the lateral walls of the mediastinal enclosure and snugly enclosing the lung root.

The pleura extens as the layer called the ______ ______ to cover the external lung surface, dipping into the lining its fissures.

Answer 213

Pleura

Parietal Pleura

Visceral Pleura

Question 214

Insufficent ventilation in relation to metabolic needs, causing them to retain CO_2.

Answer 214

Hypoventilation

Question 215

Changes in Thoracic Volume and Sequence of Events During Inspiration and Expiration

Answer 215

Question 216

The entire length of the _____ acts as aresonating chamber, to amplify and enhacne the sound quality.

Answer 216

Pharynx

Question 217

The nasal cavity is divided by a midline _____ _____ formed anteriorly by the septal cartilage and posterior by the vomer bone and perpendicular plate of ethmoid bone.

Answer 217

Nasal septum

Question 218

Surfactant

Answer 218

A detergent-like complex of lipids and proteins produced by the type II alveolar cells.

Decreases the cohesiveness of water molecules, much the way laundry deteregent reduces the attraction of water for water, allowing water to interact with and pass through fabric.

As a result, the surface tension of alveolar fluid is reduced, and less energy is needed to overcome those forces to expand the lungs and discourage alvelolar collapse.

Deeper than normal breaths, stimulate surfactant production by Type II Alveolar Cells.

Question 219

As the rib cage decends and the lungs recoil, the thoracic and intrapulmonary volumes ______. The volume _______ compresses the alveoli, and P_pul rises to about 1 mm Hg above atmospheric pressure.

Answer 219

Decreases; Decreases

Question 220

Caused by a reduced drive from the respiratory centers of the brain stem during sleep rather than by an obstruction of the airway.

Answer 220

Central sleep apnea

Question 221

Anteriorly, where the palate is supported by the palatine bones and processes of the maxillary bones, it is called the ______ ______.

Answer 221

Hard Palate

Question 222

Good enounciation depends on the muscles in the _____, ______, ______ and the _____ that “shape” sound into recognizable constants and vowels.

Answer 222

Pharynx, tongue, soft palate and the lips

Question 223

Tissue Composition of the Tracheal Wall

Answer 223

Question 224

Tidal Volume (TV)

Answer 224

During normal quiet breathing, about 500ml of air moves into and out of the lugns with each breath.

Question 225

Control of resporation primarily involves neurons in the ______ ______ of the medulla and the pons.

Answer 225

Reticular Formation

Question 226

High CO₂ levels in the blood.

Answer 226

Hypercapnia

Question 227

Minute Ventilation

Answer 227

The total amount of gas that flows into or out of the respiratory tract in 1 minute.

During normal quiet breathing, the minute ventialtion in healthy people is about 6 L/min (500ml per breath multiplied by 12 breahts per minute).

During vigorous exercise the minute ventailaiton may reach 200 L/min.

Rough yardstick for respiratory efficiency.

Question 228

The respiratory centers in the medulla and pons are sensitve to both ______ and ______ stimuli.

Answer 228

excitatory; inhibitory

Question 229

Pontine Respiratory Centers

Answer 229

Influence and modify the activtiy of medullary neurons.

Appear to smooth out the transitions from inspiration to expiration, and vice versa.

Transmit impulses to the VRG of the medulla. This modifies and fine-tunes the breathing rhyrhms generated by the VRG during certain activities such as vocalization, sleep and exercise.

Recieve input from higher brain centers and from various sensory receptors in the periphery (just like the DRG).

Question 230

Vocal folds an act as a s sphincter that prevents air passage.

Answer 230

During abdominal straining associated with defecation, the glottis closes to prevent exhalation and the abdominal muslce contract, causing the intra-abdominal pressure to rise.

Known as Valsalva maneuver.

Help empty the rexctum and can also splitn (stabilize) the body trunk when lifting a heavy load.

Question 231

The open posterior parts of the cartilage rigns, wihch like nex tto the esophagus, are connected by smooth muscle fiers of the _______ and by soft connective tissue.

Answer 231

Trachealis

Flexible, the esophogus can expand anterioly as swallowed food passses through it.

Question 232

When inspired air is cold, the vascular plexus becomes engorged with blood, intensifying the air-heating process.

Answer 232

Because these blood vessels are abundant and located superficially, nosebleleds are common and often profuse.

Question 233

3. As bicarbonate ions in plasma:

Answer 233

About 70% - The reactions that convert bicarbonate (HCO3-) for transport mostly occur inside RBCs.

When dissolved CO2 diffuses into RBCs, it combines with H2O, forming carbonic acid (H2CO3).

CO2 + H2O ⇔ H2CO3 ⇔ H+ + HCO3-

This reaction occurs in plasma, but due to carbonic anhydrase, it occurs 1000x faster in RBCs.

H+ and CO2 bind to Hb, triggering the Bohr Effect (releasing O2).

HCO3- moves quickly from the RBCS into the plasma, where it is carried to the lungs. Cl- moves from the plasma in the RBCs (chloride shift) which occurs via facilitated diffusion through an RBC membrane protein.

In the lungs, the process is reversed.

Question 234

Alveolar Dead Space

Answer 234

Some alveoli cease to act in gas exchange (due to alveolar collapse or obstrcution by mucus).

Alveolar deadspace is added to anatomical deadspace.

Question 235

The four processes of the respiratory system are:

Answer 235

Pulmonary Ventilation (Breathing)

External Respiration

Transport of Respiratory Gases

Internal Respiration

Question 236

Internal Respiration

Answer 236

O2 diffeses from the blood tot the tissue cells

CO2 diffueses from the tissues cells to the blood.

Question 237

Exercise enhanced ventilation does not appear to be prompted by rise in P_CO2 and declining PO2 and pH in the blood for two reasons:

Answer 237

1. Ventilation increases abruptly as exercise begins, followed by a gradual increase and then reaches a steady state. When exercise stops, there is a small but abrupt decline in ventilation rate, follwed by a gradual decrease to the pre-exercise value.
2. Although venous levels change, arterial P_CO2 and P_O2 levels remain surprsingly constant during exericse. In fact, P_CO2 may fall below normal and P_O2 may rise slightly because the respiratory adjustments are so efficient.

Question 238

Pacemaker neurons

Answer 238

Have intrinsic rhymicity like the pacemaker cells found in the heart. Pacemaker-like activity has been found in the VRG neurons, but supressing their activity does not abolish breathing.

A second hypothesis is that there isn’t one set, but multiple sets of pacemaker neurons that are inhibiting each other and cycle their activity to generate the rhythm.

Question 239

Forced Expiratory Volume (FEV)

Answer 239

Determines the amount of air expelled during specific time intervals of the FVC test.

Example: the volume exhaled during the first second is FEV_1. Those with healthy lungs can exahle about 80% of the FVC within 1 second.

Those with obstructive poulmoanry disease exhale considerably less than 80% of the FVC within 1 second, while those with restrictive disease can exhale 80% or more of FVC in 1 second even though FVC is reduced.

Question 240

Equation for gas flow (F):

Answer 240

F = (P₂-P₁)/R

F = Gas Flow

P₂-P₁ = Change in Pressure; Pressure Gradient between external atmosphere and the Alveoli.

R = Resistance; Mainly determined by the diameter in conducting tubes.

Question 241

Rhinitis

Answer 241

Inflammation of the nasal mucosa accompanied by excessive mucus production, nasal congestion, and postnasal drip.

Nasal mucosa is continous with the mucosa of the other respiratory passageways, explaining the typical nose to throat to chest progression of colds.

Mucosa extends tenrtacle-like into the nasolacrimal (tear) ducts and paranasal sinues, nasal cavity infections often sprea to these regions, causing sinusitis.

Change in pressure results in a sinus headache.

Question 242

Breathing cessation

Answer 242

Apnea

Question 243

Forced Expiration

Answer 243

An active process produced by contacting the abdominal wall muscles, primarly the oblqiue and transversus muscle.

1. Increase the intraabdominal prssure, which forces the abdominal organs superiorly against the diaphragm.
2. Depresses the rib cage.

Question 244

Breathing (Pulmonary Ventilation) consists of two phases:

Answer 244

Inspiration

Expiration

Question 245

Functional Residual Capacity (FRC)

Answer 245

The amount of air remaining in the ungs after a normal tidal volume expiration.

FRC = RV + ERV

Question 246

Anything other than air entering the larynx initiates the cough reflex to expel the substance.

Answer 246

This protective reflex does not work when we are unconcious, so it is never a good idea to administer liquids when attemptng to revive unconciousl person.

Question 247

Conducting Zone Passages

Answer 247

Question 248

Of all chemicals influencing respiration, ____ is the most potent and the most closely controlled.

Answer 248

CO₂

Question 249

The anterior, latreal, and posterior lung surfaces lie in close contact with the ribs and form the continously curving _____ _____.

Answer 249

Costal Surface

Question 250

Even at high altitudes, the O₂ needs by the tissues are met under ______ ______.

Answer 250

Resting conditions.

Question 251

Thyroid Cartilage

Answer 251

Formed by the fusion of two cartilage plates at the midline.

Resembers an upright open book, with the book’s “spine” lying in the anterior midline of the neck.

The larygneal prominence, which can be seen externally as the Adam’s Apple.

Typically larger in males than in females because male sex hormones stimulate its growth during puberty.

Inferior to the thyroid cartilage is the ring-shaped cricoid cartilage, perched atop and anchored to the arachea inferiorly.

Question 252

Just deep to the clavicle is the ______, the narrow superior tip of the lung.

The concave, inferior surface that rests on the diaphragm is the ______.

Answer 252

Apex

Base

Question 253

The cyclic on/off activity of the inspiratory and expiratory neurons repeats continously and produces a respiratory rate of __-__ breaths per minute, with inspiratory phases lasting about ___ seconds followed by expiratory phases lasting about ___ seconds.

Answer 253

12-16

2

3

Question 254

Increases in H⁺ excites the central chemoreceptors (brain stem), which make abundant synapses with the respiratory regulatory centers. As a result the depth and rate of breathing ______.

Answer 254

Increase

This enhances avelolar ventilation quickly flushes CO₂ out of the blood, raising pH.

Question 255

Seromucous nasal glands contain mucus-sectreting mucous cells and serous cells that secrete a watery fluid contianing enzymes.

Each day, these glands secrete about a quart (a litrer) of mucus containing ______.

Answer 255

Lysozyme, an antibacterial enzyme.

Question 256

When P_pul > P_atm, the pressure gradient forces gases to flow ____ of the lungs.

Answer 256

Out

Question 257

The paired _____ occupy all of the thoracic cavity except the ______, which houses the heart, great blood vessels, bronchi, espohagus and other organs.

Answer 257

Lungs; Mediastinum

Question 258

Contraction of the tachealis ______ the trachea’s diameter, causing expired air to rush upwwrd from the lungs with greater force.

Answer 258

Decreases

Helps expel mucus from the trachea when we cough by accelearting the xhaled air to speeds of 100 mph!

Question 259

The curved conchae greatly _____ the mucosal _____ _____ exposed to air and enhance air turbulence in the cavity.

Answer 259

Increase; Surface area

Question 260

Heimlich Maneuver

Answer 260

A procedure in which air in the victim’s lungs is uded to “pop out” or expel, an obstructing piece of food, has saved many people from becoming victims of “café coronaries”

Question 261

Tiny ______ _______ drain some systemic venous blood from the lungs, but they are multiple anastomesse between the two circulations, and most venous blood returns to the heart via the pulmonary veins.

Answer 261

Bronchial veins.

Question 262

A network of neurons that extends in the ventral brain stem from the spinal cord to the pons-medulla junction

Answer 262

Ventral Respiratory Group (VRG)

Contains Rhythm generators whose output drive respiration.

Question 263

Inspiratory depth is deteremined by how actively the _____ _____ stimulate the motor neurons serving the respiratory muscles.

Answer 263

Respirtory centers

The greater the stimulation, the greater the number of motor units excited and the greater the force of respiratory muscle contractions.

Question 264

Three pairs of small cartilage form part of the lateral and psoterior walls of the larynx.

Answer 264

Arytenoid

Cuneiform

Corniculate Cartilages

Question 265

HHb + O₂ ⇔ HbO₂ + H⁺

Answer 265

Lungs and Tissues

Question 266

Epithelium of Larynx

Answer 266

Stratified squamous epithelium line sthe superior portion of the larynx (subject to food contact).

Below the vocal chords, the epithelium is pseudostratified ciliated columnar type that filters dust.

The power stroke of its cilia is directed upward toward the pharynx to continually move mucus away from the lungs.

Question 267

Residual Volume (RV)

Answer 267

Even after the most strenuous expiration, about 1200 ml of air remains in the lungs, which healps to keep the alveoli open and prevent lung collapse.

Question 268

Pulmonary irritant relfexes communicate with the respiratory centers via ____ _____ afferents.

Accumulated in the mucus, inhaled debris such as dust or noxious fumes stimulate receptors in the ______ that promote reflex constriction of those air passages.

Answer 268

Vagal nerve

Bronchioles

Question 269

The ____ main bronchus is wider, shorter and more vertical than the ____.

Answer 269

Right; Left

More commmon for an inhaled foreign object to get stuck there.

Question 270

Hemoglobin (Hb)

Answer 270

Composed of 4 polypeptide chains, each bound to an iron-containing heme group.

Iron atoms bind to oxygen, each hemoglobin molecule can combine with four molecules of O2, and oxygen loading is rapid and reversible.

Question 271

During swallowing, the larynx is pulled ______ and the epiglottis tips to cover the ______ inlet. This action keeps food out of the lower respiratory passages, the epiglottis has been called the gaurdian of the airways.

Answer 271

Superiorly; laryngeal

Question 272

Red Blood Cells produce ______ as they metabolize glucose. ______ bind reversibly with hemoglobin and its levels rise when oxygen levels are chronically low.

Answer 272

BPG (2,3-biphosphoglycerate); BPG

Question 273

As cells metabolize glucose and use O₂, they release ______, which _____ P_CO2, and H⁺ levels in the capillary blood.

Answer 273

CO₂; Increases

C₆H₁₂O₆ (Glucose) + 6 O₂ → 6 CO₂ + 6 H₂O (Cellular Respiration)

Question 274

When P_CO2 is abnormally low, respiraton is inhibited and becomes slow and shallow. Apnea may occur until PCO2 rises and again stimulates respiration.

Answer 274

Sometimes swimmers voluntarily hyperventilate, so they can hold their breath longer during swim meets. This is dangerous.

As P_O2 drops, P_CO2, rises enough to make breathing unavailable.

Strenuous hyperventilation can lower PCO2 so much that a lag period occurs before P_CO2 rebounds enough to stimulate respiration again. The lag may allow oxygen levesl to fall well velow 50 mm Hg, causeing the swimmer to black out and perhaps drown before he or she has the urge to breath.

Question 275

Breath-holding that occurs when we are angry and increased respiratory rate that occurs when we are excited happens through the _______.

Answer 275

Hypothalamus

Question 276

The floor of the nasal cavity is formed by the _____, which separates the nasal cavity from the oral cavity below.

Answer 276

Palate

Question 277

Pulmonary Ventilation

Answer 277

Ventilation consists of inspiration and expiration.

Inspiration moves air into the lungs from the atmosphere.

Expiration moves air out of the lungs into the atmosphere

Question 278

Hyperbaric Chambers provide a clinical application of Henry’s law.

Answer 278

Chambers contain O2 gas at pressures higher than 1 atm and are used to force greater-than-normal amounts of O2 into the blood of patients suffering from carbon monoxide poisoning.

Question 279

The trachea divides to form the ____ and ____ main (primary) bronchi.

Answer 279

Right, Left

Question 280

Normal P_CO2 is ____ mm Hg and controlled within +/- ____ mm Hg.

Answer 280

40; 3

Question 281

A negative respiratory pressure in any respiratory area indicates that the pressure in that regon is ______ than the atmospheric pressure

Answer 281

Lower

• 4 mm Hg = 756 mm Hg

Question 282

Emphysema three important consequences:

Answer 282

1. Accessory muscle s must be enlisted to breathe, and victims are perpetually tired because breathing requires 15-20% of their total body energy supply (as opposed to 5% in healthy individuals).
2. The bronchioles open during inspiration but collapse during experiation, trapiing huge volumes of air in the alveoli. This leads to permanent barrel chest and flattens the diaphragm, reducing ventilation efficiency.
3. Damage to the pulmonary capillaries as the alveolar walls disintegrate increases resistance in the pulmonary circuit, forcing the right ventricle to overwork and consequently become enlarged.

Question 283

External Respiration

Answer 283

Dark red blood flowing through the pulmonary circuit is transfomred into the scarlet river that isreturned to the heart for distribution by systemic arteries to all body tissues.

The color change is due to O2 uptake and binding hemoglobin in red blood cells, but CO2 exchange (unloading) is occurng equally as fast.

Question 284

Difficult or labored breathing often reffered to as “air hunger” gets progressively worse.

Answer 284

Dyspnea

Question 285

When arterial P_O2 falls below 60 mm Hg it become sthe major sitmulus for respiration.

Answer 285

The peripheral chemoreceptors respond reflexively by increasing ventilation.

This may increase O₂ loading into the blood, but it also causes hypocapnia (low P_CO2 blood levels ) and an increase in blood pH, both of which inhibit respiration.

Question 286

Results from impaired or blocked blood circulation.

Answer 286

Ischemic (stagnant) hypoxia

Question 287

Nasal Conchae protrude medially from each lateral wall of the nasal cavity and are three scroll-like mucosa-covered projections, the _______, _______ and ______ _______ ______.

Answer 287

Inferior, middle and inferior nasal conchae.

Question 288

Respiratory pressures are always described relative to ______, which is the presssure exerted by the air (gases) surrounding the body.

Answer 288

Atmospheric Pressure (P_atn)

Question 289

Intrapulmonary and Intrapleural Pressure Relationships

Answer 289

Question 290

Changes in arterial pH due to CO₂ retention or metabolic factors act through the peripheral chemoreceptors.

Answer 290

Arterial pH does not influence the central chemoreceptors directly.

Question 291

Two patterns of COPD:

Answer 291

1. Pink puffers - work hard to maintain adequate ventilation that they lose weight, becoming thin but still having nearly normal blood gases.
2. Blue bloaters - commonly stocky build become sufficiently hypoxic that they are obviously cyanotic. Hypoxia causes constriciton of pulmonary blood vesesl leading to pulmonary hypertension and right-sided heart failure.

Question 292

Molecular oxygen is carried in the blood in two ways:

Answer 292

1. Bound to hemoglobin within red blood cells. 98.5% is carried this way.
2. Dissolved in plasma. 1.5% is carried this way.

Question 293

Trachea

Answer 293

The windpipe, descends from the larynx throught he neck and into the mediastimum.

Divides into two main bronci at midthorax.

Very flexible and moblie.

Question 294

Epiglottis

Answer 294

The ninth cartilage.

Flexible, spoon-shaped.

Composed of elastic cartilage and is almost entirely covered by a tast bud containg mucosa.

Extends from the posterior aspect of the tongue to its anchoring point on the anterior rimof the thyroid cartilage.

Question 295

Vestibular folds

Answer 295

Superior to the vocal folds is a similar pair of mucosal folds.

Play no direct part in sound proudciton but help to close the glottis when we swallow.

Question 296

Composition of Alveolar Gas

Answer 296

The atmosphere is almost entirely O2 and N2.

The alveoli contain more CO2 and water vapor and much less O2.

The differences reflect:

1. Gas exchanges occuring in the lungs.
2. Humidification of air by conducitn passages.
3. The mixing of alveolar gas that occurs with each breath (mixing new inspired gases with remaining gases in the respiratory passaageways).

O2 and CO2 are easily changed by increasing breathing depth and rate. A high AVR brings more O2 into the alveoli, increasing alveloar P_O2 and rapidly eliminating CO2 from the lungs.

Question 297

Sticky mucus traps inspired dust, bacteria and other debris, while lysozyme:

Answer 297

Attacks tand chemically destroys bacteria.