(NURS413) Respiratory System

A 53-year-old patient reports smoking two packs of cigarettes per day for the past 35 years. Calculate the pack -years for this patient.

70 Explanation 2 packs/day x 35 years = 70 pack years

Quick quiz 1. Which of the following structures is the chief respiratory unit for gas exchange? A. Acinus B. Alveoli C. Terminal bronchioles D. Pulmonary arteries

A. Acinus Answer: A. The acinus is the chief respiratory unit for gas exchange.

The exchange of gases occurs in the

Alveoli

Which of the following does NOT belong to the conducting portion of the respiratory system?

Alveoli

B. Internal intercostal muscles contract to shorten the chest's transverse diameter

ACTIVE EXPIRATION

E. Abdominal rectus muscles pull down the lower chest, depressing the ribs

ACTIVE EXPIRATION

Which of the following is a normal finding in the aging adult?

Anteroposterior diameter increases Explanation A barreled-chest is a normal finding in the aging adult due to the decreased elastic recoil of the lungs

2. How many lobes does the right lung have? A. Six B. Two C. Three D. One

C. Three Answer: C. The right lung has three lobes.

Which clinical manifestation is the main signs of lung disease?

Cough Explanation Cough is the most common symptom in lung diseases

As the nurse auscultates the patient, she hears a popping, discontinuous sound over the lung fields. This type of adventitious should is known as:

Crackles Explanation Crackles are popping. discontinuous sounds caused by fluid in the airways

4. When oxygen passes through the alveoli into the bloodstream, it binds with hemoglobin to form: A. Red blood cells B. Carbon dioxide C. Nitrogen D. Oxyhemoglobin

D. Oxyhemoglobin Answer: D. When oxygen passes through the alveoli into the bloodstream, it cinds with hemoglobin to form oxyhemoglobin.

What body structure protects the lungs from outside harm?

The rib cage. Correct. The lungs are delicate and can be bruised and even punctured. The rib cage provides protection for the lungs, but because it is rounded, it allows the lungs to fill up like balloons beneath it.

A. Pectoral muscles raise the chest to increase the anteroposterior diameter

FORCED INSPIRATION

C. Scalene muscles elevate, fix, and expand the upper chest

FORCED INSPIRATION

D. Posterior trapezius muscles raise the thoracic cage

FORCED INSPIRATION

Upper respiratory tract

The upper respiratory tract consists primarily of the nose (nostrilsand nasal passages), mouth, nasopharynx, oropharynx, laryngopharynx, and larynx. These structures filter, warm, and humidify inspired air. They're also responsible for detecting taste and smell and chewing and swallowing food. (See Structures of the respiratory system.)

When we breathe in, we inhale many gases, including oxygen. What happens to the gases that the body can't use?

They are exhaled. Correct. When we breathe air into the lungs, oxygen is absorbed into the blood through the thin walls of blood vessels. Everything else is breathed back into the air, along with the carbon dioxide brought to the lungs from the body's cells.

The volume of air in a normal breath is called

Tidal volume

The patient is scheduled to have a pulmonary function test. Further instruction is needed when she states:

" I should use my atenolol right away before the test." Explanation Atenolol is a bronchodilator that must be withheld 4-6 hours before the procedure as to not skew the results

A nurse is providing discharge instructions for a tracheostomy patient. Which statement indicates that the patient understands tracheostomy care?

" I will increase the humidity in my home." Explanation increasing humidity in the home helps thin secretions.

The nurse is suctioning a patient with an endotracheal tube. Which of the following is a correct technique for this procedure?

Hyperoxygenate before and after suctioning Explanation Hyperoxygenating before and after prevents hypoxia

Nostrils and nasal passages Just passing through

Air enters the body through the nostrils (nares). In the nares, small hairs known as vibrissae filter out dust and large foreign particles. Air then passes into the two nasal passages, which are separated by the septum. Cartilage forms the anterior walls of the nasal passages: bony structures (conchae or turbinates) form the posterior walls. The conchae warm and humidify air before it passes into the nasopharynx. Their mucus layer also traps finer foreign particles, which the cilia (small, hairlike projections) carry to the pharynx to be swallowed. It's nothing to sneeze at. These involuntary defense mechanisms help protect the respiratory system from infection and foreign-body inhalation.

Inspiration and expiration

Breathing involves two actions: inspiration (an active process) and expiration (a relatively passive process). Both actions rely on respiratory muscle function and the effects of pressure differences in the lungs. During normal respiration, the external intercostal muscles aid the diaphragm, the major muscle of respiration. The diaphragm descends to lengthen the chest cavity, while the external intercostal muscles (located between and along the lower borders of the ribs) contract to expand the anteroposterior diameter. This coordinated action causes a reduction in intrapleural pressure, and inspiration occurs. Rising of the diaphragm and relaxation of the intercostal muscles causes an increase in intrapleural pressure, and expiration results. (See Muscles of respiration.) Breathing involves two actions: inspiration and expiration.

Respiratory changes with aging Structural changes

As a person ages, the body undergoes respiratory system changes. These changes can include structural changes as well as changes in function. Age-related anatomic changes in the upper airways include nose enlargement from continued cartilage growth, general atrophy of the tonsils, and tracheal deviations from changes in the aging spine. Possible thoracic changes include increased anteroposterior chest diameter (resulting from altered calcium metabolism) and calcification of costal cartilage, which reduces mobility of the chest wall. Kyphosis advances with age because of such factors as osteoporosis and vertebral collapse. The lungs become more rigid and the number and size of alveoli decline with age. In addition, a 30% reduction in respiratory fluids heightens the risk of pulmonary infection and mucus plugs. Pulmonary function decreases in older people as a result of respiratory muscle degeneration or atrophy. Ventilatory capacity diminishes for several reasons: The lungs diffusing capacity declines: decreased inspiratory and expiratory muscle strength diminishes vital capacity. Lung tissue degeneration causes a decrease in the lungs elastic recoil capability, which results in an elevated residual volume. Thus, aging alone can cause emphysema. Closing of some airways produces poor ventilation of the basal areas, resulting in both a decreased surface area for gas exchange and reduced partial pressure of oxygen. The normal partial pressure of oxygen in arterial blood decreases to 70 to 85 mm Hg, and oxygen saturation decreases by 5%

Most oxygen in the blood is transported

As oxyhemoglobin

A nurse is reviewing the ABG values and notes a pH of 7.42, a PCO2 of 55 mm Hg, and a HCO3 of 24 mEq/L. What does the nurse interpret these values as?

Compensated respiratory acidosis Explanation The pH is WNL (7.35-7.45) which suggests that compensation has occurred. The PCO2 is higher than normal limits (35-45 mm Hg) which indicates respiratory acidosis. Since HCO3 is WNL (22-26 mEq/L) alkalosis has not taken place. Remember ROME (Respiratory Opposite Metabolic Equal)

The nurse comes into the patient's room and discovers that the patient's pulse oximetry reading is 91%. The nurse should first:

Assess the patient's respiratory status Explanation A reading between 95% -100% is WNL, while a reading less than 85% is life-threatening. Since this question asks asks what the nurse will do FIRST, the nurse should assess before implementing an appropriate intervention. Remember ADPIE.

Mechanics of ventliation

Breathing results from differences between atmospheric and intrapulmonary pressures, as described below. ^ Below inspiration, intrapulmonary pressure equals atmospheric pressure (approximately 760 mm Hg). Intrapleural pressure is 756 mm Hg. ^ The intrapulmonary atmospheric pressure gradient pulls air into the lungs until the two pressures are equal. ^ During inspiration, the diaphragm and external intercostal muscles contract, enlarging the thorax vertically and horizontally. As the thorax expands, intrapleural pressure decreases and the lungs expand to fill the enlarging thoracic cavity. ^ During normal expiration, the diaphragm slowly relaxes and the lungs and thorax passively return to resting size and position. During deep or forced expiration, contraction of internal intercostal and abdominal muscles reduces thoracic volume. Lung and thorax compression raises intrapulmonary pressure above atmospheric pressure.

3. During external gas exchange, oxygen and carbon dioxide diffusion occurs in the: A. Venules B. Alveoli C. Red blood cells D. Body tissues

B. Alveoli Answer: B. Oxygen and carbon dioxide diffusion occurs in the alveoli.

The primary chemical stimulus for breathing is the concentration of

Carbon dioxide in the blood

A postop patient who had a bronchoscopy two hours ago is NPO and states that he is hungry. What should the nurse do?

Check for a gag reflex return Explanation The anesthesia from bronchoscopy inhibits swallowing. Therefore, it is important for the nurse to check for the gag reflex as an aspiration precaution

Internal and external respiration Ventilation Nervous system influence Musculoskeletal influence Pulmonary influence The path of least resistance Increased workload, decreased efficiency Airflow interference and alterations Pulmonary perfusion Ventilation-perfusion match Diffusion The interesting thing about interstitial spaces From the RBCs to the alveoli To bind or not to bind

Effective respiration consists of gas exchange in the lungs, called external respiration, and gas exchange in the tissues, called internal respiration. Internal respiration occurs only through diffusion. External respiration occurs through three processes: ^ Ventilation-gas distribution into and out of the pulmonary airways ^ Pulmonary perfusion-blood flow from the right side of the heart, through the pulmonary circulation, and into the left side of the heart ^ Diffusion-gas movement through a semipermeable membrane from an area of greater concentration to one of lesser concentration. Ventilation is the distribution of gases (oxygen and carbon dioxide) into and out of the pulmonary airways. Problems within the nervous, musculoskeletal, and pulmonary systems greatly compromise breathing effectiveness. The central nervous system's respiratory center is located in the lateral medulla. Involuntary breathing results from stimulation of the respiratory center in the medulla and the pons of the brain. Central chemical receptors in the medulla indirectly monitor the level of carbon dioxide in the blood. Carbon dioxide exerts the main influence on breathing. When carbon dioxide levels rise, the rate and depth of breathing increases to eliminate excess carbon dioxide. Peripheral chemical receptors in the aorta and carotid arteries monitor the level of oxygen in the blood. When oxygen levels drop, respiratory rate and depth increases to improve the blood oxygen level. However, the peripheral chemical receptors are less sensitive than the central receptors and don't respond until oxygen levels are quite low. The adult thorax is flexible-its shape can be changed by contracting the chest muscles. The medulla controls ventilation primarily by stimulating contraction of the diaphragm and external intercostal muscles. These actions produce the intrapulmonary pressure changes that cause inspiration. Airflow distribution can be affected by many factors: > Airflow pattern (See Comparing airflow patterns.) > Volume and location of the functional reserve capacity (air retained in the alveoli that prevents their collapse during expiration) > Degree of intrapulmonary resistance > Presence of lung disease If airflow is disrupted for any reason, airflow distribution follows the path of least resistance The pattern of airflow through the respiratory passages affects airway resistance. Laminar flow, a linear pattern that occurs at low flow rates, offers minimal resistance. This flow type occurs mainly in the small peripheral airways of the bronchial tree. Turbulent flow, the eddying pattern of turbulent flow creates friction and increases resistance. Turbulent flow is normal in the trachea and large central bronchi. If the smaller airways become constricted or clogged with secretions, however, turbulent flow may also occur there. Transitional flow, a mixed pattern known as transitional flow is common at lower flow rates in the larger airways, especially where the airways narrow from obstruction, meet, or branch. Other musculoskeletal and intrapulmonary factors can affect airflow and, in turn, may affect breathing. For instance, forced breathing (as occurs in emphysema) activates accessory muscles of respiration, which require additional oxygen to work. This results in less efficient ventilation with an increased workload. Other airflow alterations can also increase oxygen and energy demand and cause respiratory muscle fatigue. These conditions include interference with expansion of the lungs or thorax (changes in compliance) and interference with airflow in the tracheobronchial tree (changes in resistance). Both can result in reduced tidal volume and alveolar ventilation. Pulmonary perfusion refers to blood flow from the right side of the heart, through the pulmonary circulation, and into the left side of the heart. Perfusion aids external respiration. Normal pulmonary blood flow allows alveolar gas exchange, but many factors may interfere with gas transport to the alveoli. Her are some examples: Cardiac output less than the average of 5 L/minute decreases gas exchange by reducing blood flow. > Elevations in pulmonary and systemic resistance reduce blood flow. > Abnormal or insufficient hemoglobin picks up less oxygen for exchange. Gravity can affect oxygen and carbon dioxide transport in a positive way. Gravity causes more unoxygenated blood to travel to the lower and middle lung lobes than to the upper lobes. This explains why ventilation and perfusion differ in the various parts of the lungs. Areas in which perfusion and ventilation are similar have what is referred to as a ventilation perfusion match: in such areas, gas exchange is most efficient. (See What happens in ventilation-perfusion mismatch.) During diffusion, oxygen and carbon dioxide travel the same path but in opposite directions. In diffusion, oxygen and carbon dioxide molecules move between the alveoli and capillaries. The direction of movement is always from an area of greater concentration to one of lesser concentration. In the process, oxygen moves across the alveolar and capillary membranes, dissolves in the plasma, and the passes through the red blood cell (RBC) membrane. Carbon dioxide moves in the opposite direction. The epithelial membranes lining the alveoli and capillaries must be intact. Both the alveolar epithelium and the capillary endothelium are composed of a single layer of cells. Between these layers are tiny interstitial spaces filled with elastin and collagen. Thickening in the interstitial spaces can slow diffusion. Normally, oxygen and carbon dioxide move easily through all of these layers. Oxygen moves fro the alveoli into the bloodstream, where it's taken up by hemoglobin in the RBCs. When oxygen arrives in the bloodstream, it diplaces carbon dioxide (the by-product of metabolism), which diffuses from RBCs into the blood and then to the alveoli. Move it on over! This is my turf now. Most transport oxygen binds with hemoglobin to form oxyhemoglobin: however, a small portion dissolves in the plasma. The portion of oxygen that dissolves in plasma can be measured as the partial pressure of oxygen in arterial blood, or Pao2.

Exchanging gases

Gas exchange occurs very rapidly in the millions of tiny, thin-membraned alveoli within the respiratory units. Inside these air sacs, oxygen from inhaled air diffuses into the blood while carbon dioxide diffuses from the blood into the air and is exhaled. Blood than circulates throughout the body, delivering oxygen and picking up carbon dioxide. Finally, the blood returns to the lungs to be oxygenated again. After oxygen binds to hemoglobin, RBCs travel to the tissues. Through cellular diffusion, internal respiration occurs when RBCs release oxygen and absorb carbon dioxide. The RBCs then transport the carbon dioxide back to the lungs for removal during expiration. (See Exchanging gases.)

MEDICAL TERMINOLOGY AND DISORDERS Medical Term Words epistaxis

DISORDERS OF THE RESPIRATORY SYSTEM

Table 22-2 Common Respiratory Terms Term Apnea Cheyne-Stokes respirations Cyanosis Dyspnea Eupnea Hypoxia Hypoxemia Hypercapnia Hypocapnia Hyperventilation Hypoventilation Kussmaul breathing Orthopnea Rales Rhonchi Stridor Tachypnea Wheezes

Description Temporary cessation of breathing An irregular breathing pattern characterized by a series of shallow breaths that gradually increase in depth and rate: the series of increased respirations is followed by breaths that generally decrease in depth and rate. A period of apnea lasting 10 to 60 seconds follows: the cycle then repeats. A bluish color of the skin or mucous membrane caused by a low concentration of oxygen in the blood Difficult or labored breathing Normal, quiet breathing An abnormally low concentration of oxygen in the tissues An abnormally low concentration of oxygen in the blood An abnormally high concentration of carbon dioxide in the blood An abnormally low concentration of carbon dioxide in the blood An increase in the rate and depth of respiration. Hypoventilation causes an excess exhalation of carbon dioxide and alkalosis. A decrease in the rate and depth of respiration. Hypoventilation causes a retention of carbon dioxide and acidosis. An increase in rate and depth of respiration stimulated by metabolic acidosis Difficulty in breathing that is relieved by a sitting-up position Crackles (as in snap, crackle, and pop) are small clicking sounds in the lungs that resemble rubbing hair together next to the ear. They are typically inspiratory and are believed to occur when air opens closed air spaces. Rales or crackles can be further described as moist, dry, fine, and coarse. Snoring-like sounds that generally occur with obstruction of air in the large airways (trachea and bronchi) High-pitched, wheezelike sound that can be heard on both inhalation and/or exhalation. It is caused by an obstruction of air flow in the upper airway, such as the trachea, or in the back of the throat. Rapid breathing High-pitched sounds typically on exhalation. Wheezing and other abnormal sounds can sometimes be heard without a stethoscope. Wheezing occurs when air is forced through narrow airways. Although commonly associated with asthma, wheezing may also be caused by other obstructing conditions (e.g., tumors, swelling, foreign bodies).

Gas exchange in the lungs happens by the process of

Diffusion

What aspiration precaution measures should the nurse implement to the 78-year-old patient with a tracheostomy ?

Do not rush patient Deflate cuff during meals Explanation " Don not rush patient" and "Deflate cuff during meals" are the only appropriate choices to implement aspiration precautions

A nurse is monitoring a patient who has a chest tube drainage system and notices that there is gentle bubbling in the suction control chamber. What is the appropriate nursing action for this scenario?

Document this finding Explanation Gentle bubbling indicates there is suctioning and is normal. Vigorous bubbling indicates an air leak in the chest tube system, while a blocked or kinked tube can cause bubbling to stop.

Forced inspiration and active expiration Forced inspiration Active expiration Gas station

During exercise, when the body needs increased oxygenation, or in certain disease states that require forced inspiration and active expiration, the accessory muscles of respiration also participate. During forced inspiration: The pectoral muscles in the upper chest raise the chest to increase the anteroposterior diameter The sternocleidomastoid muscles in the side of the neck raise the sternum The scalene muscles in the neck elevate, fix, and expand the upper chest The posterior trapezius muscles in the upper back raise the thoracic cage. During active expiration, the internal intercostal muscles contract to shorten the chest's transverse diameter and the abdominal rectus muscles pull down the lower chest, thus depressing the lower ribs. (See Mechanics of ventilation.) Oxygen-depleted blood enters the lungs from the pulmonary artery of the heart's right ventricle, then flows through the main pulmonary arteries into the smaller vessels of the pleural cavities and the main bronchi, throughthe arterioles and, eventually, to the capillary networks in the alveoli. Gas exchange-oxygen and carbon dioxide diffusion-takes place in the alveoli. When the body's demand for oxygen is increased, such as during exercise, the accessory muscles of respiration help us out.

The structure which closes off the larynx is the

Epiglottis

The volume of air that can be exhaled after normal exhaltation is the

Expiratory reserve volume

F. Sternocleidomastoid muscles raise the sternum

FORCED INSPIRATION

The respiratory system is primarily concerned with the delivery of oxygen to every cell in the body and the elimination of carbon dioxide. Review Your Knowledge Matching: Structures of the Respiratory Tract A. Pharynx B. Trachea C. Larynx D. Bronchus E. Paranasal sinuses F. Bronchioles G. Carina H. Alveoli Matching: Thoracic Cavity and Ventilation A. Parietal pleura B. Thoracic cavity C. Intrapleural space D. Visceral pleura E. Phrenic F. Diaphragm Multiple Choice 1. Inhalation and exhalation are 2. The bronchi, bronchioles, and alveoli are 3. The diameter of the bronchioles determines the 4. Which of the following best describes the visceral and parietal pleura? 5. If intrapleural pressure equals or exceeds intrapulmonic pressure 6. Which of the following does not occur on inhalation? 7. Which of the following describes Boyle's law? Go Figure 1. According to Figure 22-1 2. According to Figure 22-2 3. According to Figure 22-3 4. Which statement is not true about Figure 22-5? 5. According to Figures 22-4 and 22-6 6. According to Figure 22-7 and Boyle's Law 7. According to Figure 22-8 8. According to Figure 22-9 9. According to Figure 22-10 10. According to Figure 22-11

I. Structures: Organs of the Respiratory System A. Consists of the upper and lower respiratory tracts. B. Nose and nasal cavities 1. The nose and nasal cavities warm and humidify inhaled air. 2. Olfactory receptors are located in the nose. 3. The nasal cavities receive drainage from the paranasal sinuses and tear ducts. C. Pharynx (throat) 1. The nasopharynx forms a passage for air only. 2. The oropharynx and laryngopharynx form passageways for both air and food. D. Larynx (voice box) 1. The larynx is a passageway for air 2. The epiglottis is the uppermost cartilage and covers the larynx during swallowing. E. Trachea (windpipe) 1. It bifurcates into the right and left bronchi. 2. C-shaped rings of cartilage keep the trachea open. F. Bronchial tree 1. The bronchial tree contains the bronchi, bronchioles, and alveoli. 2. The bronchioles determine the radius of the respiratory air passages and therefore affect the amount of air that can enter the alveoli. 3. The alveoli are tiny grapelike air sacs surrounded by pulmonary capillaries. 4. Gas exchange occurs across the thin walls of the alveoli. G. Lungs 1. The right lung has three lobes and the left lung has only two lobes. 2. The lungs contain the structures of the lower respiratory tract. H. Pleural membranes 1. The serous membranes in the chest cavity are the parietal pleura and the visceral pleura. 2. Serous fluid between the pleural membranes prevents friction. 3. For the lungs to remain expanded, pressure in the intrapleural space must be negative. A. Respiratory includes three steps: ventilation, exchange of respiratory gases, and transport of respiratory gases in the blood. 1. Ventilation (breathing) A. The two phases of ventilation are inhalation and exhalation. B. Ventilation occurs in response to changes in the thoracic volume (Boyle's law). C. Thoracic volume changes because of the contraction and relaxation of the respiratory muscles. D. The phrenic and intercostal nerves are motor nevers that supply the diaphragm and the intercostal muscles. E. Inhalation is an active process (ATP is used during muscle contraction). Unforced exhalation is passive (no ATP used). 2. Exchange of gases A. Exchange of respiratory gases occurs by diffusion across the alveoli and pulmonary capillaries. B. Oxygen diffuses from the air in the alveoli into the blood while carbon dioxide diffuses from the blood into the alveoli. C. At the cellular layer, oxygen diffuses from the capillaries to the cells. Carbon dioxide diffuses from the cells into the capillaries, where it is transported to the lungs for excretion. 3. Transport of gases in the blood A. Most of the oxygen is transported by the red blood cell (oxyhemoglobin). B. The blood transports most carbon dioxide in the form of bicarbonate ion (HCO3). B. Amounts of air 1. Pulmonary volumes A. refers to the amounts of air moved into and out of the lungs B. pulmonary volumes are illustrated in Figure 22-10 and summarized in Table 22-1. 2. Vital capacity and anatomical dead space A. Lung capacities are combinations of pulmonary volumes. B. Vital capacity is the amount of air that can be exhaled after a maximal inhalation. C. Anatomical dead space refers to air remaining in the large conducting passageways that is unavailable for gas exchange, approximately 150 ml of air. C. Control of breathing 1. Neural control of breathing A. The respiratory center is located in the brain stem. B. The medullary respiratory center contains inspiratory and expiratory neurons. Nerve impulses travel along the phrenic and intercostal nerves to the muscles of respiration. C. The pneumotaxic center and apneustic center are in the pons. These centers help control the medullary respiratory center to produce a normal breathing pattern. D. Two other areas of the brain can affect respirations: the hypothalamus and cerebral cortex. 2. Chemical control of respiration A. Central chemoreceptors are stimulated by carbon dioxide (pCO2) and [H+]. B. Peripheral chemoreceptors are sensitive to low concentrations of oxygen and increased hydrogen ion concentration in the blood. 1. D. Bronchus the trachea branches into a right and left 2. C. Larynx called the voice box because it contains the vocal cords 3. C. Larynx mucus drains from these mucous membrane-lined structures into the nasal passages. 4. A. Pharynx the respiratory structure connected to the middle ear by the eustachian tube 5. B. Trachea large tube supported by rings of cartilage: called the windpipe 6. H. Alveoli the respiratory structures concerned with the exchange of the respiratory gases 7. H. Alveoli structure closest to the pulmonary capillaries 8. F. Bronchioles Tiny respiratory passages that delivers air to the alveoli 9. D. Bronchus respiratory passage that delivers air to the bronchioles 10. G. Carina the point at which the trachea splits: causes intense coughing when stimulated by a suction catheter 1. D. Membrane on the outer surface of each lung 2. B. Contains the pleural cavity, pericardial cavity, and mediastinum 3. C. The lung collapses when air or fluid collects in this space 4. E. The motor neuron that innervates the diaphragm 5. F. Dome-shaped muscle that is the chief muscle of inhalation 6. A. Membrane that lines the walls of the pleural cavity 7. C. Must have a negative pressure here 1. C. Referred to as ventilation. 2. C. Collectively referred to as the bronchial tree. 3. C. Air flow to the alveoli. 4. C. They are serous membranes. 5. B. The lung collapses. 6. D. Pressure within the intrapleural space becomes positive. 7. C. An increase in thoracic volume decreases intrapulmonic pressure. 1. B. The alveoli are the most distal of all structures of the bronchial tree. 2. B. The epiglottis prevents the entrance of food and water into the respiratory structures. 3. D. The left lung has two lobes whereas the right lung has three lobes. 4. C. Surfactants want to collapse the lungs. 5. D. Pressure is normally negative in the space between the visceral and parietal pleurae. 6. D. When volume increases, pressure decreases. 7. D. Intrapulmonic pressure decreases when the diaphragm contracts. 8. D. Arterial pO2 is higher than tissue pO2. 9. C. Vital capacity is equal to the tidal volume, inspiratory reserve volume, and expiratory reserve volume. 10. A. Inspiratory and expiratory neurons are located within the respiratory control center of the medulla oblongata.

What happens in ventilation-perfusion mismatch Normal Shunt Dead-space ventilation Silent unit Blue Red Purple

Ideally, the amount of air in the alveoli (a reflection of ventilation) matches the amount of blood in the capillaries (a reflection of perfusion). This allows gas exchange to proceed smoothly. This ventilation-perfusion (V/Q) ratio is actually unequal: The alveoli receive air at a rate of approximately 4 L/minute, while the capillaries supply blood at a rate of about 5 L/minute. This creates a V/Q mismatch of 4:5, or 0.8. In the normal lung, ventilation closely matches perfusion. Perfusion without adequate ventilation usually results fro airway obstruction, particularly that caused by acute diseases, such as atelectasis and pneumonia. Normal ventilation without adequate perfusion usually results from a perfusion defect such as pulmonary embolism. Inadequate ventilation and perfusion usually stems fro multiple causes, such as pulmonary embolism with resultant acute respiratory distress syndrome and emphysema. Blood with CO2 Blood with O2 Blood with CO2 and O2

The exchange of gases between blood and cells is called

Internal respiration

Which of the following describes a correct order of structures in the respiratory passeways?

Pharynx, larynx, trachea, bronchi, bronchioles

What happens to the windpipe, or trachea, before it reaches the lungs?

It branches in two directions. Correct. About half of its 13cm length is inside the chest and the rest is in the neck. The lower end of the trachea divides into two bronchi (tubes) that carry air into the lungs. One bronchus goes to the left lung, the other to the right lung.

A nurse is administering oxygen to a patient who has hypoxemia and hypercarbia. Which oxygen deliver system is appropriate for this patient?

Nasal cannula at 2L/min Explanation A nasal cannula at 2L/min is given since increased oxygen levels will disrupt the hypoxic drive to breathe causing the patient to have a respiratory despression

While the nurse interviews a patient, he verbalizes that he has difficulty breathing during sleep and uses three pillows for relief. The nurse notes that he may be experiencing:

Orthopnea Explanation Orthopnea is shortness of breath during sleep and is relieved by sitting up or stacking pillows behind the head

What important activity takes place in the lungs?

Oxygen is exchanged for carbon dioxide. Correct. When we breathe air into the moist environment of the lungs, oxygen in that air passes through the walls of the lungs into the blood stream, where it is carried to the body's cells. The blood picks up excess carbon dioxide and carries it back to the lungs, where it is exhaled.

Acid-base balance

Oxygen taken up in the lungs is transported to the tissues by the circulatory system, which exchanges it for carbon dioxide produced by metabolism in body cells. Because carbon dioxide is more soluble than oxygen, it dissolves in the blood. In the blood, most of the carbon dioxide forms bicarbonate (base): smaller amounts form carbonic acid (acid).

To go on living, the body's cells need food, water, chemicals, and ...

Oxygen. Correct. The lungs get oxygen from the air, and blood brings it from the lungs to the cells. It is used in combination with other ingredients to create energy for growth and to maintain health.

A nurse is caring for a patient who had a thoracentesis eight hours ago. While assessing the patient, the nurse observes that the patient has a rapid heart rate, rapid, shallow respirations, and has absent breath sounds to the left upper lobe of the lung. The nurse interprets this complication as:

Pneumothorax Explanation A pneumothorax, or partial or complete lung collapse, can occur within the first 24 hours following a thoracentesis.

A 37-year-old patient is admitted to the ED with dyspnea, tachypnea and pink, frothy sputum. The nurse determines that the patient is experiencing:

Pulmonary embolism Explanation Pulmonary embolism is life threatening and requires emergent medical intervention

Oxygen moves from the lungs into the bloodstream through ...

Small blood vessels in the lungs Correct. These small blood vessels, called capillaries, have thin walls that allow oxygen to seep through. This process is called diffusion.

Do You Know. . . What a Tracheostomy is?

Sometimes a part of the upper respiratory tract becomes blocked, thereby obstructing the flow of air into the lungs. To restore airflow, an emergency tracheostomy may be performed. This procedure is the insertion of a tube through a surgical incision into the trachea below the level of the obstruction. The tracheostomy by passes the obstruction and allows air to flow through the tube into the lungs.

Just the facts In this chapter, you'll learn:

Structures of the respiratory system and their functions The processes of inspiration and expiration The way in which gas exchange takes place Problems with the nervous, musculoskeletal, and pulmonary systems that can affect breathing The role of the lungs in acid-base balance.

While assessing a trachostomy patient, the nurse notices that there is a crackling sensation around the neck. The nurse suspects this complication as:

Subcutaneous emphysema Explanation Subcutaneous emphysema occurs when there is an opening in the trachea and air has leaked into the subcutaneous area of the neck

What is the respiratory system?

The body's breathing system Correct. The respiratory system moves air in and out of the body using oxygen and eliminating carbon dioxide, a gas produced when cells use oxygen. The respiratory system includes the nose, throat and lungs.

Bronchial Tree: Bronchi, Bronchioles, and Alveoli Bronchioles Re-Think 1. Explain why the trachea remains open 2. What is the "problem" caused by bronchoconstriction? Alveoli Do You Know. . . Why You May Diagnose Cystic Fibrosis by Kissing Your Baby's Face? Do You Know. . . Why Your Fingers Go "Clubbing"? Lungs Right and Left Re-Think 1. What is the primary function of the alveoli? 2. Reviewing the structures of the respiratory tract, identify at least three ways that a patient can develop an acute respiratory obstruction. Pleural membranes Pleura Pleural Cavity: A Potential Space Sum It Up! Collapsed And Expanded Lungs Why Lungs Collapse Elastic Recoil SURFACE TENSION Do You Know. . . Why a permature infant is more Apt Than a full-term infant to develop respiratory distress syndrome? Re-Think 1. List two reasons that the lungs want to collapse 2. Why does water have a high surface tension? 3. Why does a deficiency of surfactants increase the "work" of breathing? WHY LUNGS EXPAND

The bronchial tree consists of the bronchi, the bronchioles, and the alveoli. It is called a tree because the bronchi an their many branches resemble an upside-down tree. Most of the bronchial tree is in the lungs. The right and left primary bronchi are formed as the lower part of the trachea divides into two tubes. The primary bronchi enter the lungs at a region called the hilus. The primary bronchi branch into secondary bronchi, which branch into smaller tertiary bronchi. Because the heart lies toward the left side of the chest, the left bronchus is narrower and positioned more horizontally than the right bronchus. The right bronchus is shorter and wider than the left bronchus and extends downward in a more vertical direction. Because of the differences in the size and positioning of the bronchi, food particles and small objects are more easily inhaled, or aspirated, into the right bronchus. Why are tiny toys not good for tiny tots? Young children generally put toys in their mouths. The tiny toy may become lodged in the larynx or bronchus, causing an acute respiratory obstruction. Unless relieved immediately, the obstruction can be fatal. Tiny toys are responsible for many toy recalls. The upper segments of the bronchi have C-shaped cartilaginous rings, which help keep the bronchi open. As the bronchi extend into the lungs, however, the amount of cartilage decreases and finally disappears. The finer and more distal branches of the bronchi contain no cartilage. The bronchi divide repeatedly into smaller tubes called bronchioles. The walls of the bronchioles contains smooth muscle and no cartilage. The bronchiole regulate the flow of air to the alveoli. Contraction of the bronchiolar smooth muscle causes the bronchioles to contrict, thereby decreasing the bronchiolar lumen (opening) and thus decreasing the flow of air. Relaxation of the bronchioles causes the lumen to increase, thereby increasing the flow of air. An asthma attack illustrates the effect of bronchiolar smooth muscle constriction. In a person with asthma, the bronchioles hyperrespond to a particular stimulus. The bronchiolar smooth muscle then constricts, decreasing the flow of air into the lungs. The person complains of a tight chest and expends much energy trying to force air through the constricted bronchioles into the lungs. Forced air causes a wheezing sound. Bronchiolar smooth muscle relaxants are medications that cause bronchodilation, thereby improving air flow and relieving the wheezing. Let's translate this into autonomic pharmacology. The bronchioles contain beta2-adrenergic receptors. Stimulation of these receptors causes relaxation of the bronchiolar smooth muscle, thus inducing bronchodilation and improved air flow. Albuterol, a beta2-adrenergic agonist, is a bronchodilator drug. Conversely, a beta2-adrenergic blocker, such as propranolol, causes bronchoconstriction and is therefore contraindicated in asthmatic patients. The bronchioles continue to divide and give rise to many tubes called alveolar ducts. These ducts end in very small, grapelike structures called alveoli (sing., alveolus). The alveoli are tiny air sacs that form at the ends of the respiratory passages. A pulmonary capillary surrounds each alveolus. The alveoli function to exchange oxygen and carbon dioxide across the alveolar-pulmonary capillary membrane. Oxygen diffuses from the alveoli into the blood: carbon dioxide diffuses from the blood into the alveoli. Th term atelectasis refers to collapsed and airless alveoli. Atelectasis occurs commonly as a postoperativ complication and as a result of conditions such as pneumonia and cancer of the lung. Cystic fibrosis (CF) is a hereditary disease that is characterized by thickened secretions of most exocrine glands. Consequently CF affects many organs including the liver, pancreas, and especially the lungs. The production of thick bronchial secretions is of particular concern because the secretions block narrow breathing passages, causing atelectasis and pulmonary infections. Eventually lung tissue is destroyed: for this reason the clinical picture of CF is dominated by lung dysfunction. In addition, sweat glands and salivary glands produce a very salty secretion: mothers often notice the salty taste of their infants upon kissing them. Certain respiratory diseases may destroy alveoli or cause a thickening of the alveolar wall. As a result, the exchange of gases is slowed. Oxygenation of the blood may decrease, causing hypoxemia and cyanosis, and the blood may retain carbon dioxide, causing a disturbance in acid-base balance (acidosis). Patients who experience chronic hypoxemia, such as those with impaired lung and heart function, often develop clubbing of the fingers and toes. Clubbing is characterized by enlarged fingertips and toes and changes in the thickness and shape of the nails. The enlargement is due to the formation of additional capillaries and tissue hypertrophy in an attempt to deliver oxygen to the oxygen-deprived cells. The two lungs, located in the pleural cavities, extend from an area just above the clavicles to the diaphragm. The lungs are soft cone-shaped organs so large that they occupy most of the space in the thoracic cavity. The lungs are subdivided into lobes. The right lung has three lobes: the superior, middle, and inferior lobes. Because of the location of the heart in the left side of the chest, the left lung has only two lobes: the superior lobe and the inferior lobe. The upper rounded part of the lung is called the apex, and the lower portion is called the base. The base f the lung rests on the diaphragm. The amount of air the lungs can hold varies with a person's body build,age, and physical conditioning. For instance, a tall person has larger lungs than a short person. A swimmer generally has larger lungs than a "couch potato," and generally has larger lungs than a "couch potato," and the trained singer has larger lungs than the typical "shower singer." The outside of each lung and the inner chest wall are lined with a continuous serous membrane called the pleurae. The pleurae are named according to their location. The membrane on the outer surface of each lung is called the visceral pleura: the membrane lining the chest wall is called the parietal pleura. The visceral pleura and the parietal pleura are attracted to each other like two flat plates of glass whose surfaces are wet. The plates of glass can slide past one another but offer some resistance when you try to pull them apart. Between the visceral pleura and the parietal pleura is a space called the intrapleural space. The pleural membranes secrete a small amount of serous fluid (approximately 25 ml). The fluid lubricates the pleural membranes and allows them to slide past one another with little friction or discomfort. Under abnormal conditions, the intrapleural space has the potential to accumulate excess fluid, blood, and air. An excess secretion of pleural fluid is called pleural effusion. Purulent (pus) pleural effusion is called empyema. Air moves through the following structures-from the nasal cavities, to the pharynx, to the larynx, to the trachea, to the bronchi, to the bronchioles, and finally to the alveoli. When the air reaches the alveoli (the tiny air sacs at the end of the bronchial tree), the respiratory gases oxygen and carbon dioxide diffuse across the alveolar-pulmonary capillary membrane. Most of the respiratory structures conduct air to and from the lungs. Only the alveoli function in the exchange of the respiratory gases between the outside air and the blood. The lungs contain the structures of the lower respiratory tract. Pleural membranes surround the lungs and line the thoracic cavity, creating the intrapleural space or pleural cavity. Figure 22-1 shows that the lungs occupy most of the thoracic cage, but this statement must be qualified: the expanded lungs occupy most of the thoracic cage. Under normal conditions, the lungs expand like inflated balloons. Under abnormal conditions, however, a lung may collapse. What determines whether or not the lungs collapse or expand? If the thoracic cavity is entered surgically, the lungs collapse. There are two reasons why the lungs collapse: elastic recoil and surface tension. Consider a balloon and a lung (Figure 22-5, A). If you blow up a balloon but fail to tie off the open end, the air rushes out and the balloon collapses. It collapses because of the arrangement of its elastic fibers. When these fibers stretch, they remain stretched only when tension is applied (the air blown into the balloon stretches the balloon). If the end of the balloon is not tied off, the elastic fibers recoil, forcing air out and collapsing the balloon. The same can be said of the lung. The arrangement of the lung's elastic tissue is similar to the arrangement of the elastic fibers in the balloon. The elastic tissue of the lung can stretch, but it recoils and returns to its unstretched position if tension is released (see Figure 22-5, B). This is called elastic recoil. The lung also collapses for a second reason, a force called surface tension. The single alveolus in Figure 22-5, C, illustrates surface tension. A thin layer of water lines the inside of the alveolus. Water is a polar molecule: one end of the water molecule has a positive (+) charge, whereas the other end of the molecule has a negative (-) charge. Note how the water molecules line up. The positive (+) end of one water molecule is attracted to the negative (-) charge on the second water molecule. Each water molecule pulls on the other and on the water molecules beneath them. The electrical attraction of the water molecule is the surface tension. As the water molecule pulls on one another, they tend to make the alveolus smaller: in other words, they tend to collapse the alveoli. Note: The surface tension of pure water is normally very high. In the mature normal lung, special alveolar cells secrete pulmonary surfactants. Surfactants are detergent-like lipoproteins that decrease suface tension by interfering with the electrical attraction between the water molecules on the inner surface of the alveolus (see Figure 22-5, C). The secretion of surfactant is stimulated by a sigh. After every five or six breaths, a person takes a larger than normal breath (a sigh): the sigh stretches the alveoli, promoting the secretion of surfactant. Surfactants lower surface tension but do not eliminate it. Surface tension remains a force that acts to collapse the alveoli. Surfactant-secreting cells appears only during the later stages of fetal development. An infant born 2 to 3 months prematurely generally has insufficient surfactant-secreting cells. As a result, surface tension within the alveoli is excessively high, the alveoli collapse, and the infant experiences respiratory distress. The infant may die in respiratory failure. This condition is commonly called respiratory distress syndrome. Before delivery the mother may be given steroids to hasten the development of surfactant-secreting cells. In addition, a premature infant is given surfactants through inhalation in an attempt to prevent this life-threatening condition. If elastic recoil and surface tension collapse the lungs, why do they remain expanded in the normal closed thorax? Lung expansion depends on pressure within the intrapleural space. A series of diagrams in Figure 22-6 illustrates this point. In Figure 22-6, A, the three pressures are labeled P1, P2, and P3. P1 is the pressure outside the chest (the pressure in the room), also called the atmospheric pressure. P2 is the pressure in the lung, also called the intrapulmonic pressure. P3 is the pressure in the intrapleural space, also called the intrapleural pressure. Note in Figure 22-6, A, that the lungs are normally expanded.

Lungs Pleura and pleural cavities Serous fluid has serious functions

The cone-shaped lungs hang suspended in the right and left pleural cavities, straddling the heart, and anchored by root and pulmonary ligaments. The right lung is shorter, broader, and larger than the left. It has three lobes and handles 55% of gas exchange. The left lung has two lobes. Each lung's concave base rests on the diaphragm: the apex extends about 1/2" (1.5 cm) above the first rib. The pleura - the membrane that totally encloses the lung-is composed of a visceral layer and a parietal layer. The visceral pleura hugs the entire lung surface, including the areas between the lobes. The parietal pleura lines the inner surface of the chest wall and upper surface of the diaphragm. The pleural cavity-the tiny area between the visceral and parietal pleural layers-contains a thin film of serous fluid. This fluid has two functions: ^ It lubricates the pleural surfaces, which allows them to slide smoothly against each other as the lungs expand and contract. ^ It creates a bond between the layers that causes the lungs to move with the chest wall during breathing. We hang out in the right and left pleural cavities.

Sinuses and nasopharynx

The four paranasal sinuses are located in the frontal, sphenoid, and maxillary bones. The sinuses provide speech resonance. Air passes from the nasal cavity into the muscular nasopharynx through the choanae, a pair of posterior openings in the nasal cavity that remain constantly open. The nasopharynx is located behind the nose and above the throat.

Air can enter the body and travel to the lungs ...

Through the mouth and the nose Correct. Air enters the body through either the open mouth or the nose. It travels to the lungs, where the oxygen in it passes into the bloodstream.

Larynx Where and what is your voice box? Vocal cords True or false Down the wrong way From boy to young man ? Re-Think Do You Know. . . Who Heimlich Is and What He Maneuvered? Do You Know. . . How "Dumb Plant" Was Used to Control Gossip (Without, of Course, Killing the Gossiper)?

The larynx also called the voice box, is located between the pharynx and trachea. The larynx has three functions: it acts as a passageway for air during breathing, it produces sound (your voice), and it prevents food and other foreign objects from entering the distal respiratory structures. The larynx is a triangular structure made primarily of cartilage, muscles, and ligaments. The largest of the cartilaginous structures in the larynx is the thyroid cartilage. It is a tough hyaline cartilage and protrudes in the front of the neck. The thyroid cartilage is larger in men and is called the Adam's apple. The epiglottis is another cartilaginous structure, located at the top of the larynx. The epiglottis acts as a flap, a very important flap. It covers the opening of the trachea during eating so food does not enter the lungs. The larynx is called the voice box because it contains the vocal cords. The vocal cords are folds of tissue composed of muscle and elastic ligaments and covered by mucous membrane. The cords stretch across the upper part of the larynx. The glottis is the space between the vocal cords. The two types of vocal cords are the false and true vocal cords. The false vocal cords are called "false" because they do not produce sounds. Instead, the muscles in this structure help to close the airway during swallowing. The true vocal cords produce sound. Air flowing from the lungs through the glottis during exhalation causes the true vocal cords to vibrate, thereby producing sound. The loudness of your voice depends on the force with which the air moves past the true vocal cords. The pitch of your voice depends on the tension exerted on the muscles of the true vocal cords. You form sound into words with your pharynx, oral cavity, tongue, and lip movement. The nasal cavities, sinuses, and pharynx act as resonating chambers, thereby altering the quality of your voice. Listen to the different voices of your friends. One voice may sound high and squeaky, whereas another may sound low and booming. The pharynx acts as a passageway for food, water and air. Food and water in the pharynx, however, should not enter the larynx. How is food and water normally kept out of the larynx? When you breathe in air, the glottis opens, and air moves through the glottis into the tubes that carry it to the lungs. When you swallow food, however, the epiglottis covers the glottis, thereby preventing food from entering the lower respiratory passages. Instead, the food enters the esophagus, the tube that empties into the stomach. How does this happen? During swallowing, the larynx moves upward and forward while the epiglottis moves downward. If you place your fingers on your larynx as you swallow, you can feel the larynx move upward and forward. In addition to the movement of the epiglottis, the glottis closes. Compare the size of the glottis. Note that swallowing plays a key role in preventing the entrance of food or water into the respiratory tubes. Some patients develop difficulty in swallowing, particularly those who have suffered neurological damage such as a stroke. Any patient who experiences difficulty in swallowing is at risk for aspiration (entrance of food or water into the lungs). Aspiration is a large clinical problem. Why is Jack's voice lower than Jill's? At puberty, under the influence of testosterone, the male larynx enlarges and the vocal cords become longer and thicker. The larger vocal cords deepen the male voice. Changes in the larynx and vocal cords causes the boy's voice to "break" as he matures into a young man. In an earlier period in history, young choir boy's with beautiful high voices were castrated. Castration, the surgical excision of the testes, removes the source of testosterone and prevents thickening of the vocal cords. These unfortunate castrated boys continued to sing beautifully as members of the castrati choir. For obvious reasons, this practice eventually disappeared. 1. Trace the flow of air from the nose to the trachea. 2. Explain why food and water do not enter the respiratory structures during swallowing. Dr. Heimlich is a physician who developed a procedure designed to dislodge the obstructing object in a choking person. The Heimlich maneuver, or abdominal thrust, is a simple technique. The "bear hug" procedure is demonstrated an an adult below. Her are the steps for the adult: 1. Stand behind the choking person and wrap your arms around the person's waist. 2. Position your hands (fist position) between the person's navel and the bottom of the rib cage. 3. Press your fist into the abdomen with a quick upward movement. 4. Repeat several times as necessary. A tea made from dieffenbachia ("dumb plant") was give to Roman slaves before they were sent to the market to shop. The tea caused the slave's tongue and mouth to swell and paralyzed the throat. The slave was therefore unable to speak and gossip about household affairs. It is still used by some African tribes as a punishment for gossip. An overdose of the poison causes excessive swelling, obstruction of the respiratory passageways, and death by suffocation. On an updated note, acute respiratory obstruction can be induced when a patient is given a drug or food to which she is allergic. "Dumbplant ingestion" may be dead, but the anaphylactic response (respiratory obstruction) is very much alive and well.

Larynx

The larynx contains the vocal cords and connects the pharynx with the trachea. Muscles and cartilage form the walls of the larynx, including the large, shield-shaped thyroid cartilage situated just under the jaw line.

Lower respiratory tract

The lower respiratory tract consists of the trachea, bronchi, and lungs. These structures contain a mucous membrane with hairlike cilia that lines the lower tract. Cilia constantly clean the tract and carry foreign matter upward for swallowing or expectoration.

Respiratory responses Metabolic alkalosis Metabolic acidosis Imbalance woes

The lungs control bicarbonate levels by converting bicarbonate to carbon dioxide and water for excretion. In response to signals from the medulla, the lungs can change the rate and depth of breathing. This change allows for adjustments in the amount of carbon dioxide lost to help maintain acid-base balance. It takes cooperation! I send the messages. . . For example, in metabolic alkalosis (a condition resulting from excess bicarbonate retention), the rate and depth of ventilation decrease so that carbon dioxide can be retained: this increases carbonic acid levels. In metabolic acidosis (a condition resulting from excess acid retention or excess bicarbonate loss), the lungs increase the rate and depth of ventilation to eliminate excess carbon dioxide, thus reducing carbonic acid levels. When the lungs don't function properly, an acid-base imbalance results. For example, they can cause respiratory acidosis through hypoventilation (reduced rate and depth of alveolar ventilation), which leads to carbon dioxide retention. Conversely, respiratory alkalosis results from hyperventilation (increased rate and depth of alveolar ventilation), which leads to carbon dioxide elimination. . . . and we change the rate and depth of breathing together we adjust levels of carbon dioxide and maintain acid-base balance.

Which organ is made up of air-carrying tubes and tiny sacs?

The lungs. Correct. Air flows through the lungs' complicated network of air-carrying tubes called bronchiolies, which branch off the windpipe like the many branches on a tree trunk. Each branch ends in a tiny sac (or pocket) called alveoli, where oxygen passes into the bloodstream.

Muscles of respiration

The muscles of respiration help the chest cavity expand and contract. Pressure differences between atmospheric air and the lungs help produce air movement. These illustrations show the muscles that work together to allow inspiration and expiration.

Nose and nasal cavities Do You Know. . . That Your Nose Is More Than Just a Smeller?

The nose includes an external portion that forms part of the face and an internal portion called the nasal cavities. The nasal cavities are separated into right and left halves by a partition called the nasal septum, which is made of bone and cartilage. Air enters the nasal cavities through two openings called the nostrils, or nares. Nasal hairs in the nostrils filter large particles of dust that might otherwise be inhaled. In addition to its respiratory function, the nasal cavity contains the receptor cells for the sense of smell. The olfactory receptors cover the mucous membrane of the upper parts of the nasal cavity and a part of the nasal septum. Three bony projections called nasal conchae appear on the lateral walls of the nasal cavities. The conchae increase the surface area of the nasal cavities and support the ciliated mucous membranes, which lines the nasal cavities. Mucous membranes contain many blood vessels and mucussecreting cells. The rich supply of blood warms and moistens the air, and the sticky mucus traps dust, pollen, and other small particles, thereby cleansing the air as it is inhaled. Because the nose helps warm, moisten, and cleanse the air, breathing through the nose is better than mouth breathing. The nasal cavities contain several drainage openings. Mucus from the paranasal sinuses drains into the nasal cavities. The paranasal sinuses include the maxillary, frontal, ethmoidal and sphenoidal sinuses. Tears from the nasolacrimal ducts also drain into the nasal cavities. (Cry and your nose runs.) The nose does a few things real well: as you know, the nose knows smells . It also "nose" how to clean and humidify air. Equally important, the nose plays a big cosmetic role: it makes us look good and, if it doesn't, we simply rearrange it surgically until it is fashioned into a great looking nose. Nose related medical conditions or procedures are named after the rhino, who sports the mother of all noses. For instance, a rhinoplasty refers to the surgical reshaping, resizing, or realigning of the nose. Rhinorrhea refers to a runny nose, as in the commoncold or the discharge of cerebrospinal fluid from the nose. Rhinokyphosis is a humpback nose, and, of course, you can have a pain in the nose-rhinodynia. It is interesting that the rhino has captured the nose words, since the rhino's nose is merely hardened hair: it doesn't sniff or drip, and it certainly doesn't check itself in for a nose job. In some persons, the nasal septum may bend toward one side or the other, thereby obstructing the flow of air and making breathing difficult. This abnormal positioning of the septum is called a deviated septum. Surgical repair of the deviated septum (septoplasty) corrects the problem. And for the nose that snorts cocaine? Chronic exposure to the drug causes intense vasoconstriction of the blood vessels that supply the septum. The septal cartilage dies, thereby creating a hole in the septum and giving the nose a collapsed or "caved-in" appearance. Not a good look!

Oropharynx and laryngopharynx

The oropharynx is the posterior wall of the mouth. It connects the nasopharynx and the laryngopharynx. The laryngopharynx extends to the esophagus and larynx.

Pharynx

The pharynx, or throat, is located behind the oral cavity and between the nasal cavities and the larynx. The pharynx includes three parts: the nasopharynx (upper section), the oropharynx (middle section), and the laryngopharynx (lower section). The oropharynx and the laryngopharynx are part of both the digestive and respiratory systems and function as a passageway for both food and air. The pharynx conducts food toward the esophagus (tube for food to enter the stomach). The pharynx also conducts air to the larynx as it moves toward the lungs. The pharynx contains two other structures: the openings from the eustachian tubes (auditory tubes) and the tonsils. The eustachian tube connects the nasopharynx with the middle ear.

Bronchi Secondary bronchi and the hilum Branching out Respiratory bronchioles Alveoli

The primary bronchi begin at the carina. The right mainstem bronchus-shorter, wier, and more vertical than the left-supplies air to the right lung. The left mainstem bronchus delivers air to the left lung. The mainstem bronchi divide into the five lobar bronchi (secondary bronchi). Along with blood vessels, nerves, and lymphatics, the secondary bronchi enter the pleural cavities and the lungs at the hilum. Located behind the heart, the hilum is a sit on the lung's medial surface. Each lobar bronchus enters a lobe in each lung. Within its lobe, each of the lobar bronchi branches into segmental bronchi (tertiary bronchi). The segments continue to branch into smaller and smaller bronchi, finally branching into bronchioles. The larger bronchi consist of cartilage, smooth muscle, and epithelium. As the bronchi become smaller, they lose cartilage and the smooth muscle. Ultimately, the smallest bronchioles consist of just a single layer of epithelial cells. Bronchi branch out-from lobar bronchi to segmental bronchi to bronchioles. Each bronchiole includes terminal bronchioles and the acinus-the chief respiratory unit for gas exchange. (See A close look at a pulmonary airway.) Within the acinus, terminal bronchioles branch into yet smaller respiratory bronchioles. The respiratory bronchioles feed directly into alveoli at sites along their walls. The respiratory bronchioles eventually become alveolar ducts, which terminate in clusters of capillary-swathed alveoli called alveolar sacs. Gas exchange takes place through the alveoli. Alveolar walls contain two basic epithelial cell types: ^ Type I cells are the most abundant. It is across these thin, flat, squamous cells that gas exchange occurs. ^ Type II cells secrete surfactant, a substance that coats the alveolus and promotes gas exchange by lowering surface tension.

Structure: Organs of the respiratory system Upper and lower respiratory tracts

The respiratory system contains the upper and lower respiratory tracts. The upper respiratory tract contains the respiratory organs located outside the chest cavity: the nose and nasal cavities, pharynx, larynx, and upper trachea. The lower respiratory tract consists of organs located in the chest cavity: the lower trachea, bronchi, bronchioles, and alveoli. The lower parts of the bronchi bronchioles, and alveoli are located in the lungs. The pleural membranes and the muscles that form the chest cavity are also part of the lower respiratory tract. Most of the respiratory organs are concerned with condution, or movement, of air through the respiratory passages. The alveoli are the tiny air sacs located at the end of the respiratory passages. They are concerned with the exchange of oxygen and carbon dioxide between the air and the blood across the walls of the pulmonary capillaries. It is critical that the airway remains open: airway obstruction is life threatening!

A look at the respiratory system

The respiratory system maintains the exchange of oxygen and carbon dioxide in the lungs and tissues. It also helps regulate the body's acid-base balance. Functionally, the respiratory system is composed of a conducting zone and a respiratory zone. The conducting zone consists of the continuous passageway that transports air in and out of the lungs (nose, pharynx, larynx, trachea, bronchi, and bronchioles). The respiratory zone, composed of the bronchioles, alveolar ducts, and alveli, performs gas exchange. The respiratory system consists of the: > upper respiratory tract > lower respiratory tract > thoracic cavity Hey, want to trade? I'll give you a little oxygen for a bit of carbon dioxide.

Locating lung structures in the thoracic cage From an anterior view From a posterior view

The ribs vertebrae, and other structures of the thoracic cage act as landmarks that can be used to identify underlying structures. From an anterior view The base of each lung rests at the level of the sixth rib at the midclavicular line and the eighth rib at the midaxillary line. The apex of each lung extends about 3/4" to 1 1/2" (2 to 4 cm) above the inner aspects of the calvicles. The upper lobe of the right lung ends level with the fourth rib at the midclavicular line and with the fifth rib at the midaxillary line. The middle lobe of the right lung extends triangularly from the fourth to the sixth rib at the midclavicular line and to the fifth rib at the midaxillary line. Because the left lung doesn't have a middle lobe, the upper lobe of the left lung ends level with the fourth rib at the midclavicular line and with the fifth rib at the midaxillary line. From a posterior view The lungs extend from the cervical area to the level of T10. On deep inspiration, the lungs may descend to T12. An imaginary line, stretching from the T3 level along the inferior border of the scapulae to the fifth rib at the midaxillary line, separates the upper lobes of both lungs. The upper lobes are situated above T3: the lower lobes are situated below T3 and extend to the level of T10. The diaphragm originates around the ninth or tenth rib.

Mediastinum

The space between the lungs is called the mediastinum. It contains the: > Heart and pericardium > Thoracic aorta > Pulmonary artery and veins > Venae cavae and azygos veins > Thymus, lymph nodes, and vessels > Trachea esophagus, and thoracic duct > Vagus, cardiac, and phrenic nerves.

Thoracic cage Posterior thoracic cage Anterior thoracic cage Attached or floating free? Bordering on the costal angle It's suprasternal

The thoracic cage is composed of bone and cartilage. It supports and protects the lungs, allowing them to expand and contract. The vertebral column and 12 pairs of ribs form the posterior portion of the thoracic cage. The ribs form the major portion of the thoracic cage. They extend from the thoracic vertebrae toward the anterior thorax. The ribs, like the vertebrae, are numbered from top to bottom. The anterior thoracic cage consists of the manubrium, sternum, xiphoid process, and ribs. It protects the mediastinal organs that lie between the right and left pleural cavities. Ribs 1 through 7 attach diresctly to the sternum: ribs 8 through 10 attach to the cartilage of the preceding rib. The other 2 pairs of ribs are "free-floating"-they don't attach to any part of the anterior thoracic cage. Rib11 ends anterolaterally, and rib 12 ends laterally. The lower parts of the rib cage (costal margins) near the xiphoid process form the borders of the costal angle-an angle of about 90 degrees in a normal person. (See Locating lung structures in the thoracic cage.) Above the anterior thorax is a depression called the suprasternal notch. Because the suprasternal notch isn't covered by the rib cage like the rest of the thorax, the trachea and aortic pulsation can be palpated here. (See Respiratory changes with aging.) Because the suprasternal notch isn't covered by the rib cage, the trachea and aortic pulsation can be palpated here.

Thoracic cavity

The thoracic cavity is the area surrounded by the diaphragm (below), the scalene muscles and fasciae of the neck (above), and the ribs, intercostal muscles, vertebrae, sternum, and ligaments (around the circumference).

Trachea

The trachea extends from the cricoid cartilage at the top to the carina (also called the tracheal bifurcation). C-shaped cartilage rings reinforce and protect the trachea to prevent it from collapsing. The carina is a ridge-shaped structure at the level of T6 or T7.

Trachea Where it sits and where it splits Keeping it open

The trachea, or windpipe, is a tube 4 to 5 inches (10 to 12.5cm) long and 1 inch (2.5cm) in diameter. The trachea extends from the larynx downward into the thoracic cavity, where it splits into the right and left bronchi ( sing., bronchus). The trachea splits, or bifurcates, at a point called the carina at the manubriosternal junction (where the manubrium of the sternum meets the sternal body). Why is the carina so important clinically? The carina is very sensitive: touching it during suctioning causes vigorous coughing. The purpose of the trachea? It conducts air to and from the lungs. The trachea lies in front of the esophagus, the food tube. C-shaped rings of cartilage partially surround the trachea for its entire length and serve to keep it open. The rings are open on the back side of the trachea so that the esophagus can bulge forward as food moves along the esophagus to the stomach. You can feel the cartilaginous rings if you run your fingers along the front of your neck. Without this strong cartilaginous support, the trachea would collapse and shut off the flow of air through the respiratory passages. Because of the cartilaginous rings, a tight collar or neckie does not collapse the trachea. A severe blow to the anterior neck, however, can crush the trachea and cause an acyte respiratory obstruction. The trachea must be kept open.

While auscultating a 65-year-old patient, the nurse hears bronchovesicular breath sounds over the lung fields. How does this nurse interpret this finding?

This is a normal finding Explanation Bronchovesicular breath sounds are normally heard over the major bronchi. When heard elsewhere, this would indicate normal aging or an abnormality

What is the purpose of the little hairs inside the nose?

To keep dust out of the lungs. Correct. It is important to keep dust and other impurities out of the lungs. The tiny hairs in the nose trap unwanted particles before they can go too far into the respiratory system.

What is another name for the windpipe?

Trachea. Correct. As it's bottom, the trachea branches into two tubes called bronchi, which lead into the lungs.

Just for fun

Unscramble the words on the left to discover what occurs when the body needs increased oxygenation.

A nurse is caring for a patient who had a surgical placement of a tracheostomy 48 hours ago. What should the nurse's initial action be if tube dislodgement occurs?

Ventilate the patient using a manual resuscitation bag as another nurse notifies for help from the resuscitation team Explanation Tube dislodgement that occurs 72 hours after surgery is an emergency. As such, ventilating the patient first is priority. Remember your ABCs.

A patient with a chronic lung disease arrives on the med-surg unit. Which delivery system would offer the most precise oxygen concentration for this patient?

Venturi facemask Explanation The venturi mask offers the most accurate flow rate than the nasal cannula and is therefore preferred for a patient with chronic lung disease