HPP(RESPIRATORY SYSTEM)

cilia become sluggish, allowing mucus to accumulate in the nasal cavity and to dribble outward through the nostrils. This helps explain why you might have a “runny” nose on a crisp, wintry day.

most disabling respiratory disorders, the group of diseases collectively referred to as (blank)

These diseases have certain features in common:

(1) Patients almost always have a history of smoking;
(2) dyspnea (disp'ne-ah), difficult or labored breathing, often referred to as "air hunger" occurs and becomes progressively more severe;
(3) coughing and fre quent pulmonary infections are common; and
(4) most COPD victims are hypoxic, retain carbon dioxide and have respiratory acidosis, and ulti mately develop respiratory failure

are a major cause of death and disability in the United States.

In (blank), the mucosa of the lower respiratory passages becomes severely in flamed and produces excessive amounts of mucus. The pooled mucus impairs ventilation and gas ex change and dramatically increases the risk of lung infections, including pneumonias.

patients are sometimes called "blue bloaters" because hypoxia and carbon dioxide retention occur early in the disease and cyanosis is common.

Chronic bronchitis patients are sometimes called "blank" because hypoxia and carbon dioxide retention occur early in the disease and cyanosis is common.

In (blank), the alveoli enlarge as the walls of adjacent chambers break through, and chronic inflammation promotes fibrosis of the lungs. As the lungs become less elastic, the airways collapse dur ing expiration and obstruct outflow of air. As a result, these patients use an incredible amount of energy to exhale, and they are always exhausted. Because air is retained in the lungs, oxygen exchange is surpris ingly efficient, and cyanosis does not usually appear until late in the disease.

Consequently, patient/sufferers are sometimes referred to as "pink puffers." However, overinflation of the lungs leads to a permanently expanded barrel chest.

emphysema sufferers are sometimes referred to as "blank." However, overinflation of the lungs leads to a permanently expanded barrel chest.

is the leading cause of cancer death for both men and women in North America, caus ing more deaths than breast, prostate, and colorec tal cancer combined. This is tragic, because largely preventable-nearly 90 percent of result from smoking.

Ordinarily, nasal hairs, sticky mucus, and the action of cilia do a fine job of protecting the lungs from iritants, but (blank) overwhelms these cleansing devices and they eventually stop function ing.

Continuous irritation prompts the production of more mucus, slows the movements of cilia that clear this mucus and depresses lung macrophages.

One result is a pooling of mucus in the lower respiratory tree and an increased frequency of pulmonary infections, including pneumonia and chronic obstructive pulmonary disease (COPD).

However, it is the irritating effects of the "cocktail" of free radicals, highly addictive nicotine, and other carcinogens in tobacco smoke that ultimately lead to lung cancer.

The three most common types of lung cancer are:

(25-30 percent of cases), which arises in the epithelium of the larger bronchi and tends to form masses that hollow out and bleed

(40 percent), which originates as solitary nodules in peripheral lung areas and develops from bronchial glands and alveolar cells

(about 20 percent), which contains lymphocyte-like cells that originate in the main bronchi and grow aggressively in small grapelike clusters within the mediastinum, a site from which metastasis is especially rapid.

The most effective treatment for lung cancer is complete removal of the diseased lung lobes in an attempt to halt metastasis. However, removal is an option open to very few lung cancer patients because metastasis has usually occurred by the time the cancer is diagnosed. In most cases, radiation therapy and chemotherapy are the only options, but most lung cancers are resistant to these treatments.

Fortunately, there are several new therapies on the horizon. These include:

(1) antibodies that target specific molecules required by the tumor
or that deliver toxic agents directly to the tumor,
(2) cancer vaccines to stimulate the immune system,
(3) various forms of gene therapy to
replace the defective genes that make tumor cells divide continuously. As clinical trials progress, we will learn which of these approaches is most effective. But remember, prevention is worth a pound of cure. Quitting smoking is a valuable goal. Consider the alternative.

In the fetus, the lungs are filled with fluid, and all respiratory exchanges are made by the (blank).

At birth, the fluid-filled pathway is drained, and the respiratory passageways fill with air. The alveoli inflate and begin to function in gas exchange, but the lungs are not fully inflated for 2 weeks.

The success of this change that is, from non functional to functional respirationdepends on the presence of surfactant (sur-fak'tant), a fatty molecule made by the cuboidal alveolar cells, lowers the surface tension of the film of water lining each alveolar sac so that the alveoli do not collapse between each breath. Surfactant is not usually present in large enough amounts to accomplish this function until late in pregnancy, that is, between 28 and 30 weeks.

Infants who are born prematurely (before week 28) or in whom surfactant production is inad equate for other reasons (as in many infants born to diabetic mothers) have (blank)

These infants have dyspnea within a few hours after birth and use tremendous amounts of energy just to keep re inflating their alveoli, which collapse after each breath. Although IRDS still accounts for over 20,000 newborn deaths a year, many of these babies survive now because of the current use of equipment that supplies a positive pressure con tinuously and keeps the alveoli open and working in gas exchange until the maturing lungs produce adequate amounts of surfactant.

Important birth defects of the respiratory sys tem include cleft palate and (blank), the most common lethal genetic disease in the United States, strikes in 1 out of ev ery 2,400 births, and every day two children die of it. CF causes oversecretion of a thick mucus that clogs the respiratory passages and puts the child at risk for fatal respiratory infections.

It affects other secretory processes as well. Most important, it impairs food digestion by clogging ducts that deliver pancreatic enzymes and bile to the small intestine. Also, sweat glands produce an extremely salty perspiration. At the heart of CF is a faulty gene that codes for the CFTR protein. CFTR Works as a chloride (CI-) channel to control the flow of CI into and out of cells. In people with the mu tated gene, CFTR gets "stuck" in the endoplasmic reticulum and is unable to reach the plasma mem brane to perform its normal role. Consequently, less CI- is secreted and less water follows, result ing in the thick mucus typical of CE The goal of CF research is to restore normal salt and water movement. Conventional therapy for CF is mucus dissolving drugs, "clapping" the chest to loosen the thick mucus, and antibiotics to prevent infection. A surprisingly simple approach is to inhale hypertonic saline droplets.

The respiratory rate is highest in newborn in fants, about 40 to 80 respirations per minute. It con tinues to drop through life: In the infant it is around 30 per minute, at 5 years it is around 25 per minute, and in adults it is 12 to 18 per minute. However, the rate often increases again in old age.

The lungs con tinue to mature throughout childhood, and more alveoli are formed until young adulthood. But in people who begin smoking during the early teens, the lungs never completely mature, and those additional alveoli are lost forever.

(blank), also called crib death, claims many newborn infants. Apparently healthy infants stop breathing and die in their sleep, leaving their anguished par ents to face charges of child abuse in some cases. Believed to be a problem of neural control of respiration, most cases occur in infants placed in a prone position (on their abdomen) to sleep. Since 1992, the recommendation to place infants on their back to sleep has resulted in a decline of 40 percent in SIDS cases in the United States.

Except for sneezes or coughs (responses to irritants), and the occasional common cold that blocks the upper respiratory passageways with mucus, the respiratory system works so efficiently and snoothly that we are not even aware of it. Most problems that occur are a result of external factors-for example, obstruction of the trachea by a piece of food, or aspiration of food particles or vomitus (which leads to aspiration pneumo nia).

Some unfortunate individuals are plagued by (blank), caused by chronically inflamed, hy persensitive bronchial passages that respond to many irritants (such as dust mite and cockroach droppings, dog dander, and fungi) with dyspnea, coughing, and wheezing. hygiene may be related to recent increases in cases of asthma.

As we age, the chest wall becomes more rigid and the lungs begin to lose their elasticity, result ing in a slowly decreasing ability to ventilate the lungs. Vtal capacity decreases by about one-third by the age of 70. In addition, blood oxygen levels decrease, and sensitivity to the stimulating effects of carbon dioxide decreases, particularly in a re clining or supine position. As a result, many old people tend to become hypoxic during sleep and exhibit (blank)

Additionally, many of the respiratory system's protective mechanisms also become less efficient with age. Ciliary activity of the mucosa decreases, and the phagocytes in the lungs become sluggish. The net result is that the elderly population is more at risk for respiratory tract infections, par ticularly pneumonia and influenza.

In (blank), for example, inspiration is obstructed and the IRV and VC decrease.

In (blank) for example, where expiration is hampered, the ERV is much lower than normal, and the residual volume is higher.

Taking a deep breath, closing glottis, and forcing air superiorly from lungs against
glottis. Then, the glottis opens suddenly, and a blast of air rushes upward. act to clear the lower respiratory passageways.

Impaired oxygen transport:

Whatever the cause, inadequate Oxygen delivery to body tissues is called (blank) This condition is easy to recognize in fair-skinned people be cause their skin and mucosae take on a bluish cast (become cyanotic; si'ah-not'ik).

In dark-skinned individuals, this color change can be observed only in the mucosae and nailbeds. may be the result of anemia, pulmonary disease, or im paired or blocked blood circulation.

Similar to a cough, except that expelled air is directed through nasal cavities instead of through oral cavity. The uvula (u′vu-lah), a tag of tissue hanging from the soft palate, becomes depressed and closes oral cavity off from pharynx, routing the air through nasal cavities. clear upper respiratory passages.

(blank) represents a unique type of hypoxia. Carbon monoxide (Co)is an odorless, colorless gas that competes vigorously with oxygen for the same binding sites on hemoglobin. Moreover, because hemoglobin binds to CO more readily than to oxygen, carbon mon Oxide is a very successful competitorso much so that it crowds out or displaces oxygen.

is the leading cause of death from fire. It is particularly danger ous because it kills its victims softly and quietly. It does not produce the characteristic signs of hypoxiacyanosis and respiratory distress. Instead, the victim becomes confused and has a throbbing headache. In rare cases, the skin becomes cherry red (the color of the hemoglobin-CO complex), which is often interpreted as a healthy "blush." People with CO poisoning are given 100 per cent oxygen until the carbon monoxide has been cleared from the body.

Impulses go ing back and forth between the medulla centers maintain a rate of 12 to 15 respirations/minute. This normal respiratory rate is referred to as (blank)

Pons centers appear to smooth out the basic rhythm of inspiration and expiration set by the medulla.

During exercise, we breathe more vigorously and deeply because the brain centers send more impulses to the respiratory muscles. This respira tory pattern is called (blank)

However, the rate of breathing may not be sig nificantly increased with exercising. After strenu ous exercise, expiration becomes active, and the abdominal muscles and any other muscles capable of lifting the ribs are used to aid expiration.

Inspiration followed by release of air in a number of short expirations. Primarily an emotionally induced mechanism.

We all have con sciously controlled our breathing pattern at one time or another. During singing and swallowing, breath control is extremely important, and many of us have held our breath for short periods to swim underwater. However, voluntary control of breathing is limited, and the respiratory centers will simply ignore messages from the cortex (our wishes) when the oxygen supply in the blood is getting low or blood pH is falling. All you need do to prove this is to try to talk normally or to hold your breath after unning at breakneck speed for a few minutes. It simply cannot be done. Many toddlers try to manipulate their parents by hold ing their breath "to death." Even though this threat causes many parents to become anxious, they need not worry because the involuntary controls take over and normal respiration begins again.

also modify the rate and depth of breathing. Have you ever watched a horror movie with bated (held) breath or been so scared by what you saw that you were nearly panting? Have you ever touched something cold and clammy and gasped? AIl of these result from reflexes initiated by emotional stimuli acting through centers in the hypothalamus.

Although many factors can modify respiratory rate and depth, the most im portant factors are chemicalthe levels of carbon dioxide and oxygen in the blood. Increased levels of carbon dioxide and decreased blood pH are the most important stimuli leading to an increase in the rate and depth of breathing. (Actually, an increase in carbon dioxide levels and decreased blood pH are the same thing in this case, because carbon dioxide retention leads to increased levels of carbonic acid, which decrease the blood pH.)

Changes in carbon dioxide concentrations in the blood seem to act directly on the medulla centers by influencing the pH of cerebrospinal fluid (CSF)Conversely, changes in oxygen concentration in the blood are detected by peripheral chemoreceptor regions in the aorta (aortic body in the aortic arch) and in the fork of the common carotid artery the carotid body).

These, in turn, send impulses to the medulla when blood oxygen levels are dropping. Although every cell in the body must have oxygen to live, it is the body's need to rid itself of carbon diox ide (not to take in Oxygen) that is the most important stimulus for breathing in a healthy person. Decreases in oxygen levels become important stimuli only when the levels are dangerously low.

In people who retain carbon dioxide, such as people with emphysema, chronic bronchitis, or other chronic lung diseases, the brain no longer recognizes increased levels of carbon dioxide as important. In such cases, dropping oxygen levels become the respiratory stimulus. This interesting fact explains why such patients are always given (blank)

If they were given high levels, they would stop breathing because their respiratory stimulus (low oxygen levels) would be gone.

The respiratory system in healthy individuals has homeostatic mechanisms. As carbon dioxide or other sources of acids begin to accumulate in blood and blood pH starts to drop, you begin to breathe more deeply and more rapidly. Notice that this breathing pattern, called hyperventilation, is distinct from the hyperpnea of exercise.

(blank) blows off more carbon dioxide and decreases the amount of carbonic acid, which returns blood pH to the normal range.

By contrast, when blood starts to become slightly alkaline, or basic (for whatever reason), breathing slows and becomes more shallow. Slower breathing allows carbon dioxide to accumulate in the blood and brings blood pH back into normal range.

Indeed, control of breathing during rest is aimed primarily at regulating the hydrogen ion con centration in the brain.

(blank) (extremely slow or shallow breathing) or byperventilation can dramatically change the amount of carbonic acidin the blood. Carbonic acid increases dramatically during... and decreases substantially during hyperventilation.

In both situations, the buffering ability of the blood is likely to be over whelmed; the result is acidosis or alkalosis.

Carbonic acid increases dramatically during hypoventilation and decreases substantially during hyperventilation. In both situations, the buffering ability of the blood is likely to be over whelmed; the result is

Hyperventilation, often brought on by anxiety at tacks, frequently leads to brief periods of (blank), cessation of breathing, until the carbon dioxide builds up in the blood again.

If breathing stops for an extended timne, cyanosis may occur as a result of insufficient oxygen in the blood. In addition, the hyperventilating person may get dizzy and faint because the resulting alkalosis causes cerebral blood vessels to constrict. Such attacks can be prevented by having the hyperventilating individual breathe into a paper bag.

Because exhaled air contains more carbon dioxide than atmo spheric air, it upsets the normal diffusion gradient that causes carbon dioxide to be unloaded from the blood and leave the body. As a result, carbon dioxide (and thus carbonic acid) levels begin to rise in the blood, ending alkalosis.

Essentially same as crying in terms of the air movements produced. Also an emotionally induced response.

Sudden inspirations resulting from spasms of diaphragm; initiated by irritation of diaphragm or phrenic nerves, which serve diaphragm. The sound occurs when inspired air hits vocal folds of closed glottis.

Very deep inspiration, taken with jaws wide open; ventilates all alveoli (this is not the case in normal quiet breathing).

Laughing and crying reflect our emotions. For the most part, these (blank) are a result of reflex activity, but some may be produced voluntarily.

is the actual exchange of gases between the alveoli and the blood (pulmonary gas exchange)

is the gas exchange process that occurs between the systemic capillaries and the tissue cells.

Diseased respiratory tissue, mucus, or pus can produce abnormal sounds such as:

(blank)* (a bubbling sound)
(blank)** (a whistling sound)
(black)*** are abnormal bronchial sounds produced by the presence of mucus or exudate in the lung passages or by thickening of the bronchial walls.

are produced by air rushing through the large respiratory passageways (trachea and bronchi)

occur as air fills the alveoli. The vesicular sounds are soft murmurs that resemble a muffled breeze.

(blank) in healthy people is largely a passive process that depends more on the natural elasticity of the lungs than on muscle contraction.

As the inspiratory muscles relax and resume their initial resting length, the rib cage (blank)*. Thus, both the thoracic and intrapulmonary volumes decrease. As the in trapulmonary volume decreases, the gases inside the lungs are forced more closely together, and the intrapulmonary pressure rises to a point higher than atmospheric pressure. This causes the gases to flow out to equalize the pres sure inside and outside the lungs.

*expiration

The lungs adhere tightly to the (blank) (because of the surface tension of the fluid between the pleural membranes), so they are stretched to the new, larger size of the thorax.

Air continues to move into the lungs until the in trapulmonary pressure equals atmospheric pressure. This series of events is called

Under normal circumstances, expiration is effortless, but if the respiratory passageways are narrowed by spasms of the bronchioles (as in astbma) or clogged with mucus or fluid (as in chronic bronchitis or pneu monia), expiration becomes an active process. In such cases of (blank)* the internal inter costal muscles are activated to help depress the rib cage, and the abdominal muscles contract and help to force air from the lungs by squeezing the abdominal organs upward against the diaphragm.

*expiration

Normally the pressure within the pleural space, the (blank), is always negative, and this is the major factor preventing collapse of the lungs. If for any reason the becomes equal to the atmospheric pressure, the lungs immediately recoil completely and collapse.

During (blank), or lung col lapse, the lung is useless for ventilation. This phenomenon occurs when air enters the pleural space through a chest wound, but it may also result from a rupture of the visceral pleura, which allows air to enter the pleural space from the respiratory tract.

*The presence of air in the intrapleural space, which disrupts the fluid bond between the pleurae, is referred to as (blank)

* is reversed by drawing air out of the intrapleural space with chest tubes, which allows the lung to reinflate and resume its normal function.

*Many factors affect respiratory capacity—for example, a person’s size, sex, age, and physical condition.

*Normal quiet breathing moves approximately 500 ml of air (about a pint) into and out of the lungs with each breath. This respiratory volume is referred to as the (blank)

As a rule, a person can inhale much more air than is taken in during a normal, or tidal, breath. The amount of air that can be taken in forcibly over the tidal volume is the (blank). Normally, the ..... is around 3,100 ml.

Similarly, after a normal expiration, more air can be exhaled. The amount of air that can be forc ibly exhaled after a tidal expiration, the (blank), is approximately 1,200 ml.

*Even after the most strenuous expiration, about 1,200 ml of air still remains in the lungs, and it cannot be voluntarily expelled. This is the (blank)

*air is impor tant because it allows gas exchange to go on con tinuously even between breaths and helps to keep the alveoli open (inflated).

The total amount of exchangeable air (around 4,800 ml in healthy young men and 3,100 ml in healthy young women) is the (blank)

The vital capacity is the sum of the (blank)

As (blank) (the volume within the lungs) increases, the gases within the lungs spread out to fill the larger space. The resulting decrease in the gas pressure in the lungs produces a partial vacuum (pressure less than atmospheric pres sure), which sucks air into the lungs

*inspiration

Note that much of the air that enters the respiratory tract remains in the conducting zone passage ways and never reaches the alveoli. This is called the (blank) and during a normal tidal breath, it amounts to about 150 ml. The functional volume-air that actually reaches the respiratory zone and contributes to gas exchange is about 350 ml.

Respiratory capacities are measured with a (blank*). As a person breathes, the volumes of air exhaled can be read on an indicator, which shows the changes in air volume inside the apparatus. ..... testing is useful for evaluating losses in respiratory functioning and following the couse of some respiratory diseases.

The nasal cavity is separated from the oral cavity below by a partition

(blank) create a gentle current that moves the sheet of contaminated mucus posteriorly toward the throat (pharynx), where it is swallowed and digested by stomach juices.

moistens the air and traps incoming bacteria and other foreign debris

the mucus destroy bacteria chemically.

The rest of the mucosa lining the nasal cavity, rests on a rich network of thin-walled veins that warms the air as it flows past. (Because of the superficial location of these blood vessels, nosebleeds are common and often profuse.)

the sense of smell are located in the mucosa in the slitlike superior part of the nasal cavity, just beneath the ethmoid bone.

“pug” or “ski-jump” in shape, is the only externally visible part of the respiratory system.

During breathing, air enters the nose by
passing through the

The interior of the nose consists of the (blank)

The interior of the nose consists of the nasal cavity divided by a midline

(terminal air sacs) Because gas
exchanges with the blood happen only in the

the other respiratory system structures are really just (blank) that allow air to reach the lungs

(blank) include the nose, pharynx, larynx, trachea, bronchi and their smaller branches, and the lungs, which contain the alveoli

(blank and blank) share responsibility for supplying the body with oxygen and disposing of carbon dioxide.

oversee the gas exchanges that occur between the blood and the external environment

Using (blank) as the transporting fluid, the cardiovascular system organs transport respiratory gases between the lungs and the tissue cells.

If either system fails (cardiovascular & respiratory), body cells begin to die from (blank and blank)

*The lateral walls of the nasal cavity are uneven, owing to three mucosa-covered projections, or lobes

*greatly increase the surface area of the mucosa exposed to the air

*also increase the air turbulence in the nasal cavity. As the air swirls through
the twists and turns, inhaled particles are deflected onto the mucus-coated surfaces, where they are trapped and prevented from reaching the lungs.

(palate) supported by bone,
is the

(palate) unsupported posterior part
is the

The genetic defect (failure of the bones forming the palate to fuse medially) results in breathing difficulty as well as problems with oral cavity functions such as chewing and speaking.

*The nasal cavity is surrounded by a ring of
(blank) located in the frontal, sphenoidal, ethmoid, and maxillary bones

*lighten the skull, and
they act as resonance chambers for speech.

*also produce mucus, which drains into the nasal cavities.

*suctioning effect created by nose
blowing helps to drain the sinuses

drain tears from the eyes, also
empty into the nasal cavities.

inflammation of the nasal mucosa. The
excessive mucus produced results in nasal congestion and postnasal drip.

can cause rhinitis

* is difficult to treat and can cause marked changes in voice quality.

* When the passageways connecting the sinuses to the nasal cavity are blocked with mucus or infectious matter, the air in the sinus cavities is absorbed.

* The result is a partial vacuum and a sinus headache localized over the inflamed area.

*is a muscular passageway
about 13 cm (5 inches) long

* throat

*serves as a common
passageway for food and air

*It is continuous with the nasal cavity anteriorly via the posterior nasal aperture.

Air enters the superior portion, the *(blank), from the nasal cavity and then descends through the **(blank)
and ***(blank) to enter the larynx below.

Food enters the mouth and then travels along with air through the oropharynx and laryngopharynx. But instead of entering the larynx, food is directed into the (blank) posteriorly.

drain the middle ear, open into the nasopharynx.

(blank)*, which drain the middle ear, open into the nasopharynx. The mucosae of these two regions are continuous, so ear infections such as (blank)** may follow a sore throat or other types of pharyngeal infections.

*Clusters of lymphatic tissue called (blank) are also found in the pharynx.

*also play a role in protect ing the body from infection.

often called adenoid, is located high in the nasopharynx.

are in the oropharynx at the end of the soft palate

which lie at the base of the tongue.

If the pharyngeal tonsil becomes inflamed and swollen (as during a bacterial infection), it obstructs the nasopharynx and forces the person to breathe through the mouth. In mouth breathing, air is not properly moistened, warmed, or filtered before reaching the lungs. Many children seem to have this condition, called

*(voice box) routes air and fod into the proper channels and plays a role in speech. Located inferior to the pharynx

*is formed by eight rigid hyaline cartilages and a spoon-shaped flap of elastic cartilage

* “guardian of the airways,”

* When we are not swallowing, does not restrict the passage of air into the lower respiratory passages.

*When we swallow food or fluids, the situation changes damatically; the larynx is pulled upward and the (blank) tips, forming a lid over the larynx’s opening. This routes food into the esophagus, or food tube, posteriorly

The largest of the hyaline cartilages is the shield-shaped, which protrudes anteriorly and is commonly called the Adam’s apple.

Part of the mucous membrane of the larynx forms a pair of folds, called the (blank), or (blank), which vibrate with expelled air. This ability to vibrate allows us to speak.

The vocal folds and the slitlike passage way between them are called the (blank).

* Air entering the (blank), or (blank), from the larynx travels down its length (10–12 cm, or about 4 inches) to the level of the fifth thoracic vertebra, which is approximately midchest.

* is fairly rigid because its walls are reinforced with C-shaped rings hyaline cartilage

The trachea is fairly rigid because its walls are reinforced with C-shaped rings of (blank). These rings serve a double purpose. The open parts of the rings abut the esopbagus and allow it to expand anteriorly when we swallow a large piece of food. The solid portions support the trachea walls and keep it patent, or open, in spite of the pressure changes that occur during breathing.

The solid portions support the trachea walls and keep it (blank) in spite of the pressure changes that occur during breathing.

The (blank) muscle abuts the esophagus and completes the wall of the trachea posteriorly.

(blank), a procedure in which the air in a per son's own lungs is used to "pop out," or expel, an obstructing piece of food, has saved many people from becoming victims of such “café coronaries." The (blank) is simple to learn and easy to do. However, it is best learned by demon stration, because cracked ribs are a distinct possibility when it is done incorrectly.

In some cases of obstructed breathing, an emergency (blank) (surgical opening of the trachea) is done to provide an alternative route for air to reach the lungs. Individuals with (blank*) in place form huge amounts of mucus the first few days because of irritation to the trachea. Thus, they must be suctioned frequently during this time to prevent the mucus from pooling in their lungs.

The trachea is ined with a (blank)

The (blank) beat continuously and in a direction opposite to that of the incoming air. They propel mucus, loaded with dust particles and other debris, away from the lungs to the throat, where it can be swallowed or spat out.

Smoking inhibits (blank) and ultimately destroys the cilia. Without these cilia, coughing is the only means of preventing mucus from ac cumulating in the lungs. Smokers with respiratory congestion should avoid medications that inhibit
the cough reflex.

The (blank) are formed by the division of the trachea.

Each main bronchus runs obliquely before it plunges into the (blank) of the lung on its own side

The (blank) is wider, shorter, and straighter than the left. Consequently, it is the more common site for an inhaled foreign object to become lodged.

By the time incoming air reaches the bronchi, it is (blank, 3).

The (blank) are fairly large organs. They occupy the entire thoracic cavity except for the most central area, the mediastinum

the (blank), which houses the heart (in its inferior pericardial cavity re gion), the great blood vessels, bronchi, esophagus, and other organs

The narrow superior portion of each lung, the (blank), is just deep to the clavicle.

The broad lung area resting on the diaphragm is the (blank).

Each lung is divided into lobes by fissures; the left lung has (blank) lobes, and the right lung has (blank).

The surface of each lung is covered with a visceral serosa called the (blank)

the walls of the thoracic cavity are lined by the (blank).

The pleural membranes produce (blank), a slippery serous secretion which allows the lungs to glide easily over the thorax wall during breathing movements and causes the two pleural layers to cling together.

The (blank) can slide easily from side to side across one another, but they strongly resist be ing pulled apart.

the lungs are held tightly to the thorax wall, and the (blank) is more of a potential space than an actual one. As we describe shortly, this tight adherence of the pleural membranes is absolutely essential for normal breathing.

(blank),

*inflammation of the pleura, can be caused by decreased secretion of pleural fluid. The pleural surfaces become dry and rough, resulting in friction and stabbing pain with each breath.

After entering the lungs, the main bronchi sub divide into smaller and smaller branches (second ary and tertiary bronchi, and so on), finally ending in the smallest of the conducting passageways, the (blank)

respiratory passageways within the lungs, the network formed is often referred to as the (blank). AIl but the smallest branches have reinforcing cartilage in their walls.

The (blank) lead into respiratory zone structures, even smaller conduits that eventu ally terminate in alveoli or air sacs.

alveol

The (blank) which includes the respiratory broncbioles, alveolar ducts, alveolar sacs, and alveoli, is the only site of gas exchange.

All other respiratory passages are (blank) that serve as conduits to and from the respiratory zone. There are millions of the clustered alveoli, which resemble bunches of grapes, and they make up the bulk of the lungs.

The balance of the lung tissue, its (blank), is mainly elastic connective tissue that allows the lungs to recoil passively as we exhale. Thus, in spite of their relatively large size, the lungs weigh only about 2½ pounds, and they are soft and spongy.

The walls of the alveoli are composed largely of a single, thin layer of (blank). The thinness of their walls is hard to imagine, but a sheet of tissue paper is much thicker.

(blank) connect neighboring air sacs and provide alternative routes for air to reach alveoli whose feeder bronchioles have been clogged by mucus or otherwise blocked.

The external surfaces of the alveoli are covered with a "cobweb of pulmonary capillaries. Together, the alveolar and capillary walls, their fused basement membranes, and occasional elastic fibers construct the (blank) (air-blood barrier), which has gas (air) flowing past on one side and blood flowing past on the other

The gas exchanges occur by simple diffusion through the respiratory membrane oxygen pass ing from the alveolar air into the capillary blood and carbon dioxide leaving the blood to enter the gas-filled alveoli.

It has been estimated that the total gas exchange surface provided by the alveolar walls of a healthy man is (blank), or approximately 40 times greater than the surface area of his skin.

The final line of defense for the respiratory system is in the alveoli. Remarkably efficient (blank), sometimes called "dust cells," wander in and out of the alveoli picking up bacteria, carbon particles, and other debris.

Also scattered amid the epithelial cells that form most of the alveolar walls are chunky cuboidal cells, which look very different from the squamous epithelial cells. These cells produce a lipid (fat) molecule called (blank), which coats the gas-exposed alveolar surfaces and is very important in lung function

Air must move into and out of the lungs so that the gases in the air sacs (alveoli) of the lungs are continuously refreshed

This process of pulmonary ventilation
is commonly called (black).

Gas exchange (oxygen loading and carbon dioxide unloading) be tween the pulmonary blood and alveoli must take place. Remember that in external respira tion, gas exchanges are being made between the blood and the body exterior.

Oxygen and car bon dioxide must be transported to and from the lungs and tissue cells of the body via the bloodstream.

At systemic capillaries, gas exchanges must be made between the blood and tissue cells. Gas exchanges are occurring between the blood and cells inside the body.

To do this, at least four distinct events, collectively called respiration:

the actual use of oxygen and pro duction of carbon dioxide by tissue cells, that is, (blank), is the cornerstone of all energy-producing chemical reactions in the body. occurs in all body cells

Breathing, or pulmonary ventilation, is a completely mechanical process that depends on volume changes Occurring in the (blank).

is a rule to keep in mind about the mechanics of breathing:

(blank), when air is flowing into the lungs,

(blank), when air is leaving the lungs.

When the inspiratory muscles, the diaphragm and external intercostals, contract, the size of the thoracic cavity increases.

As the dome-shaped diaphragm contracts, it moves (blank)* As a result, the superior-inferior dimension (height) of the thoracic cavity (blank)**. Contraction of the external intercostals lifts the rib cage and thrusts the sternum forward, which in creases the anteroposterior and lateral dimensions of the thorax.