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Bukovinian State Medical University

Department of Developmental Pediatrics


to the practical class for medical students of 3-rd years

Modul 2: Physiologicoanatomical peculiarities of the systems in children

Submodul 6: Respiratory system in children

Topic 4:


It is completed by:

MD, MSc, PhD Strynadko Maryna

Chernivtsy - 2007

SUBJECT: Propedeutical Pediatrics.



  1. To learn anatomical peculiarities of organs of respiration in children.

  2. To learn physiological peculiarities of organs of respiration in children.

  3. To know rules of clinical inspection of children of different age.

  4. To know rules of carrying out of additional laboratory and instrumental methods of research and to have ability to do interpretation of results.

  5. To know semiotics of respiratory diseases in children of different age.

  6. To consider general questions of pathogenesis and clinics of the most widespread syndromes, which are characterizing for respiratory diseases.

  7. The student should be able to collect the anamnesis from infant’s mother and mother of the older child.

  8. The student should be able to conduct objective investigation of the respiratory system.

  9. To reveal the basic syndromes and symptoms of respiratory diseases as a result of independent investigation of respiratory system in children.

^ PROFESSIONAL MOTIVATION: The respiratory pathology is one of the most often pathology in childhood, especially in the infants and toddlers. Knowledge of normal structure and function and of differences between childhood and adult respiratory systems is important for recognizing and understanding age-related diseases patterns and providing effective therapy.


Respiratory system in the newborn

The respiratory tract consists of a complex of structures that function under neural and hormonal control. At birth the respiratory system is relatively small, but after the first breath the lungs grow rapidly. The shape of the chest changes gradually from a relatively round configuration at birth to one that is more or less flattened in the anteroposterior diameter in adulthood. In severe obstructive lung disease the anteroposterior measurement approaches the transverse measurement. Periodic measurements provide clues to the course of lung disease or the efficacy of therapy.

Changes take place in the air passages that increase respiratory surface area. For example, during the first year the alveoli in the terminal units rapidly increase in number. In addition, the early globular alveoli develop septa causes them to become more lobular. They continue to increase steadily until, at the age of 12 years, there are approximately nine times as many as were present at birth. In later stages of growth the structures lengthen and enlarge.

After the early weeks of life the respiratory tract follows t general growth curve. However, the respiratory apparatus grows fast than the vertebral column, resulting in alterations in the relation between these structures. The bifurcation of the trachea lies the third thoracic vertebra in the infant opposite the fourth vertebra in the adult; the , descends from the level of the fourth cervical vertebra in to that of the sixth in the adult. These anatomic changes p differences in the angle of access to the trachea at various ages must be considered when the infant or child is to be positio purposes of resuscitation and airway clearance. The larynx growth slowly until puberty, when its accelerated growth produce in the voice that are particularly marked in boys.

Respiratory movements are first evident at approximately weeks gestation, and throughout fetal life there is an exchange amniotic fluid in the alveoli. In the neonate the respiratory rate rapid to meet the needs of a high metabolism. During growth rate steadily decreases in both boys and girls until it level; maturity. The volume of air inhaled increases with the growth; lungs and is closely related to the body size. In addition, there qualitative difference in expired air at different ages. The oxygen in the expired air gradually decreases and the carbon dioxide increases during growth. Other important aspects of the respiratory function are discussed as they relate to prenetal life and perinatal adjustments, the newborn infant, and acute and chronic respiratory problems of infants and children.

Main functions of respiratory system in children:

  • Breathing and gas exchange function

  • Defence function

  • Metabolic function

  • Deposited function

  • Filtrated function

  • Endocrine function

Breathing and gas exchange function is the vital function of human. The gas exchange via alveolar-capillary membrane provides the supplying of human body the oxygen. The oxygen from the environment air goes through tracheal-bronchial tree into alveoli and exchange simultaneously with carbon dioxide from venous blood. If physician need to estimate the ventilation and gas exchange function in children one uses the lung volumes estimation.

The respiratory tract consists of a complex of structures that function under neural and hormonal control. At birth the respiratory system is relatively small, but after the first breath the lungs grow rapidly. The shape of the chest changes gradually from a relatively round configuration at birth to one that is more or less flattened in the anteroposterior diameter in adulthood. In severe obstructive lung disease the anteroposterior measurement approaches the transverse measurement. Periodic measurements provide clues to the course of lung disease or the efficacy of therapy.

^ Anatomy-morphological peculiarities of respiratory system

Nasal Cavity

The nasal cavity has three main functions. The first is the cleansing, warming, and moistening of inspired air. It achieves this via nasal hairs (vibrissae) extending from the inner lining of the nostrils (which filter macrophages), and the mucus-secreting goblet cells in the nasal epithelium (which hydrate air and pick up smoke and dust). Also assisting in the nasal cavity functions are the pseudostratified columnar epithelium lining the conchae (which are ciliated and responsible for air transport), along with the highly vascular nasal epithelium (which warm the air), and the turbinate bones (which circulate the air in the cavity).

Another function of the nasal cavity relates to our sense of smell. The upper medial portion of the nasal cavity is lined by specialised types of epithelium which contain mucus-secreting cells and olfactory cells. In mammals other than higher primates, olfactory epithelium extends over a large surface area providing a highly developed sense of smell.

The final nasal cavity function relates to phonation, as the nasal cavity acts as a resonating chamber and is associated with voice phonetics.


The pharynx connects the nasal and oral cavities to the larynx. Its supporting walls are composed of skeletal muscle, and the lumen is lined with mucous membrane, which eases the passage of food, and further humidifies and cleanses inspired air.

The pharynx is composed of three regions. The first is the nasopharynx. It is the uppermost part of the pharynx and lies directly behind the nasal cavity. It only has a respiratory function. The middle region of the pharynx is the oropharynx, and it is involved in the passage of both air and food. The final, lower section of the pharynx is the laryngopharynx. It opens into both the oesphagus and the trachea. In the laryngopharynx, respiratory and digestive systems become distinct.


The larynx connects the laryngophayrnx to the trachea. It primary functions consist of permitting the passage of air during breathing, prevention of food or fluid from entering the trachea during swallowing, and the production of sound via the "voice box". The larynx is composed of a framework involving 9 cartilages. There are 3 large single cartilages, thyroid cartilage, epiglottis, and cricoid cartilage. The other 6 cartilages are 3 pairs involved in the production of sound; the arytenoid, cuneiform, and corniculate cartilage pairs.


The trachea, also known as the windpipe, connects the larynx to the primary bronchi. It is stiffened by 16-20 C-shaped rings of cartilage. The open part of the ring is located posteriorly and covered by fibrous connective tissue and smooth muscle. The lumen of the trachea is lined with pseudostratified ciliated columnar epithelium. The epithelium contains mucus-secreting goblet cells which trap inhaled dust particles. The beating of the cilia on the epithelium carries mucus and trapped particles up to the pharynx where it is removed by a cough reflex. At the lower end of the trachea, it divides to form right and left primary bronchi.

^ Bronchial Tree

The bronchial tree consists of primary, secondary, and segmental bronchi, bronchioles, and terminal bronchioles which divide to form alveolar ducts. The bronchi contain hyaline cartilage rings in their walls, so as to keep the air ways open. The lumen of bronchi is lined by pseudostratified columnar epithelium. The bronchioles contain little cartilage in their walls, instead having a thick layer of smooth muscle which controls the size of the lumen. The lumen of bronchioles is lined by simple cuboidal epithelium.


The alveoli are the final branching of the respiratory tree and act as the primary gas exchange units of the lung. The gas-blood barrier between the alveolar space and the pulmonary capillaries is extremely thin, allowing for rapid gas exchange. To reach the blood, oxygen must diffuse through the alveolar epithelium, a thin interstitial space, and the capillary endothelium; CO2 follows the reverse course to reach the alveoli. There are two types of alveolar epithelial cells. Type I cells have long cytoplasmic extensions which spread out thinly along the alveolar walls and comprise the thin alveolar epithelium. Type II cells are more compact and are responsible for producing surfactant, a phospholipid which lines the alveoli and serves to differentially reduce surface tension at different volumes, contributing to alveolar stability.


The lung surfactant is a surface active substance covering the respiration system of the lung. Type II pneumocytes produce the surfactant which is stored as lamellar bodies and finally released into the alveolar fluid phase. At the air/water-interface spreading establishes a molecular film which dynamically adapts the surface tension to the actual area of the interface during breathing. The lung surfactant consists of lipids - mainly lecithine (DPPC), unsaturated phosphatidyl cholins (PCs), negatively charged phosphatidyl glycerols (PGs), and proteins. Two out of four specific proteins, SP-B and SP-C, together with lipids seem to be responsible for its surface active properties. Pulmonary surfactant is a surface-active lipoprotein formed by type II alveolar cells. The proteins and lipids that comprise surfactant have both a hydrophilic region and a hydrophobic region. By adsorbing to the air-water interface of alveoli with the hydrophilic headgroups in the water and the hydrophobic tails facing towards the air, the main lipid component of surfactant, dipalmitoylphosphatidylcholine, reduces surface tension.

Thus, there are some physiologico-anatomical peculiarities of the respiratory system in children

The peculiarities of the nose:

  1. The nose consists particular by of cartilage,

  2. The nasal meatuses are narrow,

  3. There is no inferior nasal meatuse (until 4 years),

  4. Undeveloped submucosal membrane (until 8-9 years).

The peculiarities of sinuses in children

  1. The maxillary sinus is usually present at birth,

  2. The frontal sinuses begin to develop in early infancy,

  3. The ethmoid and sphenoid sinuses develop later in childhood.

The peculiarities of the pharynx at the neonate

  1. The pharynx is relatively small and narrow,

  2. The auditory tubes are small, wide, straight and horizontal.

The peculiarities of the larynx at the neonate

  1. The larynx is funnel-shaped (in the adult it is relatively round),

  2. It is relatively long,

  3. The cricoid's cartilage descendents from the level of the fourth cervical vertebra in the infant to that of the sixth in the adult

  4. The fissure of glottis is narrow and its muscles fatigue soon,

  5. Vocal ligaments and mucous membrane are very tender and well blood-supplied,

  6. Vocal ligament are relatively short.

The peculiarities of the trachea:

  1. The length of the trachea is relatively larger (about 4 cm (in the adult 7 cm) and wide,

  2. It is composed of 15-17 cartilage rings (the amount does not increase),

  3. The bifurcation of the trachea lies opposite the third thoracic vertebra in infant and descends to a position opposite the fourth vertebra in the adult,

  4. Mucus membrane is soft, well blood supplied, but sometime dry,

  5. It can collapse easily.

The peculiarities of the bronchi:

  1. in young children the bronchi are relatively wide,

  2. the right bronchus is a straight continuation of the trachea,

  3. the muscle and elastic fibres are undeveloped,

  4. the lobules are segmental bronchus are narrow.

The peculiarities of the lung:

  1. size of alveoli is smaller than in adult,

  2. quantity of alveoli is relatively less than adult.

Clinical examination of the respiratory system in children include history talking, inspection, palpation, percussion and auscultation.

More often complaints in children who have respiratory troubles:

    1. cough

    2. catarrh

    3. respiration rate or rhythm disorders

    4. non-specific complaints.

Inspection of respiratory system consists of some steps:

  1. face inspection

  2. nose inspection

  3. neck inspection

  4. thorax inspection

Inspection of the lungs involves primarily observation f respiratory movements, which are discussed. Respirations are iluated for (1) rate (number per minute), (2) rhythm (regular, irregular or periodic), (3) depth (deep or shallow), and (4) quality ss, automatic, difficult, or labored). The doctor also notes the breath sounds based on inspection without the aid of such as noisy, grunting, snoring, or heavy, e respiratory rate at rest of the child of different age is: 40-35 per minute, 35-30 per min

Disorders of the respiratory rate:

  • Tachypnea is the increase of the respiratory rate.

  • Bradypnea is the decrease of the respiratory rate.

  • Dyspnea is the distress during breathing.

  • Apnea is the cessation of breathing.

Disorders of the respiratory depth:

  • Hyperpnea is an increased depth.

  • Hypoventilation is a decreased depth and irregular rhythm.

  • Hyperventilation is an increased rate and depth.

Pathological respiration

  • Seesaw (paradoxic) respirations: the chest falls on inspiration and rises on expiration. It is usually observed in respiratory failure of third degree;

  • Kussmaul's breathing is hyperventilation, gasping and labored respiration, usually seen in diabetic coma or other states of respiratory acidosis:

Examination of the lungs in children

The lungs are situated inside the thoracic cavity, with one lung on each side of the sternum. Each lung is divided into an apex, which is slightly pointed and rises above the first rib, a base, which is wide and concave and lies on the domeshaped diaphragm, and a body, which is divided into lobes.

The right lung has three lobes: upper, middle, and lower. The left lobe has only two lobes, upper and lower, because of the space occupied by the heart. The two surfaces of the lungs are the costal surface, which faces the chest wall and backs up to the vertebral column, and the mediastinal surface, which faces the space lying between the lungs, the mediastinum. The center of the mediastinal surface is called the hilus where the bronchus and blood vessels enter the lung.

Palpation. Respiratory movements are felt by placing each hand flat against the back or chest with the thumbs in midline along the lower costal margin of the lungs. The child should be sitting during this procedure and, if cooperative, should take several deep breaths. During respiration the hands will move with the chest wall. The doctor evaluates the amount and speed of respiratory excursion, noting any asymmetry of movement. Normally in older children the posterior base of the lungs descends 5 to 6 cm (about 2 inches) during a deep inspiration.

The doctor also palpates for vocal fremitus, the conduction of voice sounds through the respiratory tract. With the palmar surfaces of each hand on the chest, the doctor asks the child to repeat words such as "ninety-nine", "one, two, three," "eee-eee" etc. The child should speak the words with a voice of uniform intensity. Vibrations are felt as the hands move symmetrically on either side of the sternum and vertebral column. In general vocal fremitus is the most intense in the regions of the thorax where the trachea and bronchi are the closest to the surface, particularly along the sternum between the first and second ribs and posteriorly between the scapulae. Progressing downward, the sound decreases and is least prominent at the base of the lungs. Crepitation is felt as a coarse, cracking sensation as the hand presses over the affected area. It is the result of the escape of air from the lungs into the subcutaneous tissues from an injury or surgical intervention. Both pleural friction rubs and crepitation can usually be heard as well as felt.

Percussion. The lungs are percussed in order to evaluate the densities of the underlying organs. Resonance is heard over all the lobes of the lungs that are not adjacent to other organs. Dullness is heard beginning at the fifth interspace in the right midclavicular line. Percussing downward to the end of the liver, a flat sound is heard because the liver no longer overlies the air-filled lung. Cardiac dullness is felt over the left sternal border from the second to the fifth interspace medially to the midclavicular line. Below the fifth interspace on the left side, tympany results from the air-filled stomach. Deviations from these expected sounds are always recorded and reported.

In comparative percussing the chest, the anterior lung is percussed from apex to base, usually with the child in the supine or sitting position. Each side of the chest is percussed in sequence in order to compare the sounds.

The pathological dullness is heard in cause of

  1. pneumonia

  2. hydro-, haemothorax,

  3. pulmonary edema,

  4. lung or mediastinal tumor.

The banbox is heard in cause of:

  1. emphysema of lungs,

  2. cavern of lung,

  3. abscess of lung,

  4. pneumothorax,

  5. bronchial asthma,

  6. asthmatic bronchitis.

In topographic percussing the chest, the doctor looks for the lungs' borders in the main lines, the location of the apex of the lung and width of Crenig's areas. The topographic percussion is used only in children older 7 years old.

The line

The side

Age of child, rib

By 10 yr

Older 10 yr






















In topographic percussion the margin of the lung is assessed from the side of resonance sound.

The upper margin of the lung (the location of the apex of the lung) is determined by percussions from the clavicle to the neck. The apex of each lung rises about 2 to 4 cm above the inner third oi the clavicles in front of the body. At the back we examine the location of the apex of the lung by percussions from the scapula axis to the seventh cervical vertebra. Normally, the upper border of the lung is in the seventh cervical vertebra at the back.

Auscultation. Auscultation involves using the stethoscope to evaluate breath and voice sounds. Breath sounds are best heard if the child inspires deeply. The child can be encouraged to "take a big breath" by following a demonstration of "breathing in through the nose and out through the mouth." Younger children respond well to games such as blowing out the light from a cigarette lighter or the light of the otoscope.

In the lungs breath sounds are classified as vesicular or bronchovesicular. Vesicular breath sounds are normally heard over the entire surface of the lungs, with the exception of the upper intrascapular area and the area beneath the manubrium. Inspiration is louder, longer, and higher-pitched than expiration. Sometimes the expiratory phase seems nearly absent in comparison to the long inspiratory phase. The sound is a soft, swishing noise.

Bronchovesicular breath sounds are normally heard over the manibrum and in the upper intrascapular regions where there are bifurcations of large airways. Inspiration is louder and higher in pitch than that heard is vesicular breathing.

Puerile breath sounds are one of normal types of breathing in children from 6 month till 3 or 7 (if astenic) years old. Puerile breath sounds have shot inspiration and louder, a hollow expiratory phase, blowing character.\

Another type of breathing thar is normal only over the trachea near the suprasternal notch is bronchial breath sounds. They are almost the reverse of vesicular sounds; the inspiratory phase is short and the expiratory phase is longer, louder and of higher pitch.

Rough breath sounds have shot inspiration and louder phase. Rough breath has hollow and blowing character.

Absent or diminished breath sounds are always an abnormal finding warranting investigation. Fluid, air, or solid masses in the pleural space all interfere with the conduction of breath sounds (pneumonia pneumo-, hydro-, haemothorax, tumor of lung or mediastinal, emphysema of lungs, atelectasis, airways obstruction, a forcing body in the bronchus). Diminished breath sounds in certain segments of the lung can alert the doctor to pulmonary areas that may benefit from postural drainage and percussion. Increased breath sounds following pulmonary therapy indicate improved passage of air through the respiratory tract.

Voice sounds are also part of auscultation of the lungs. Normally voice sounds or vocal resonance is heard, but the syllables are indistinct. They are elicited in the same manner as vocal fremitus, except that the doctor listens with the stethoscope. Consolidation of the lung tissue produces three types of abnormal voice sounds – whisperes pectoriloquy, bronchophony and egophony.

Rales result from the passage of air through fluid or moisture. They are more pronounced when the child takes a deep breath. Even though the sound may seem continuous, it is actually composed of several discrete sounds, each originating from the rupture of a small bubble. The type of rales is determined by the size of the passageway and the type of exudate the air passes through. They are roughly divided into three categories: fine, medium, and coarse.

Fine rales (sometimes called crepitant rales) can be simulated by rubbing a few strands of hair between the thumb and index finger close to the ear or by slowly separating the thumb and index finger after they have been moistened with saliva. The result is a series of fine crackling sounds. Fine rales are most prominent at the end of inspiration and are not cleared by coughing. They occur in the smallest passageways, the alveoli and bronchioles.

Medium rales are not as delicate as fine rales and can be simulated by listening to the "fizz" from recently opened carbonated drinks or by rolling a dry cigar between the fingers. They are prominent earlier during inspiration and occur in the larger passages of the bronchioles and small bronchi.

Coarse rales are relatively loud, coarse, bubbling, gurgling sounds that occur in the large airways of the trachea, bronchi, and smaller bronchi. Often they clear partially during coughing.

Rhonchi are sounds produced as air passes through nai ageways, regardless of the cause, such as exudate, infl ior. Rhonchi are continuous, since sound being forced past an obstruction.

Sibilant rhonchi are high pitched, musical, wheezing, or sque; king in character. The wheezing quality is often more pronouno forced expiration. Sibilant rhonchi are produced in the smaller bronchi and bronchioles.

Sonorous rhonchi are low pitched and often snoring or moaning in character. They are produced in the large passages of the trache; and bronchi. Like coarse rales, they can be partly cleared by coughing.


1. What average respiration rate is typical for 1 year infant in the rest?

1. 40-60 per min

2. 30-35 per min*

3. 20-25 per min

4. 16-18 per min

5. 10-15 per min

2. In what period the embryogenesis of pulmonary system (bronchi, vessels and alveolus) was started?

1. 1 week

2. 2 week

3. 4 week

4. 6 week*

5. 8 week

3. Where the lower border of right lung must be estimation in 3-year child on linea medio-clavicullaris?

1. 6 rib*

2. 7 rib

3. 8 rib

4. 9 rib

5. 10 rib

4. What the additional breath sounds do you know in children?

1. Ronchi and crackles*

2. Pectoral fremitus

3. Bronchial breathing

4. Vesicular breathing

3. All listed above

5. When is the puerile breathing auscultated in children?

1. 1 month - 6 month

2. 6 month - 3 year*

3. 6 month – 12 month

4. 12 month - 3 year

5. 12 month – 5 year

6. What indexes can be estimated by peakflowmetry in children?

1. peak velocity of exhalation (L/min)*

2. tidal volume , ml

3. expiratory reserve volume, ml

4. vital capacity, l

5. functional residual capacity, l

7. What kinds of hypoxia do you know in children?

1. hypoxic

2. circulatory

3. anemic

4. histotoxic

5. all listed above*

8. From what age the development of frontal sinus is beginning in children?

1. from 1st month

2. from 6th month

3. from 1st year

4. from 2nd year*

5. from 5th year

9. What clinical method can you use to pectoral fremitus estimation?

1. palpation*

2. percussion

3. auscultation

4. visual inspection

5. all listed above

10. You want to receive the pleural fluid to further analysis. What method you must use?

1. thoracocentes *

2. lung biopsy

3. bronchoscopy

4. laparoscopy

5. all listed above


1. Anatomical and physiological peculiarities of organs of respiration in children of different age (the upper respiratory ways, middle respiratory ways, the lower respiratory ways).

2. The general peculiarities of clinical inspection of children of different age.

3. Rules and methods of objective investigation of respiratory organs in children.

4. Peculiarities of an auscultation technique depending on age of the child.

5. The mechanism of occurrence of additional respiratory sounds.

6. The types of dyspnea in children.

7. The types of pathological respiration.

8. Semiotics of changes of percussion sound.

9. Disorders of the respiratory rate and depth.

10. The basic syndromes of respiratory diseases.


    1. Nelson Textbook of Pediatrics / edited by Richard E. Behrman, Robert M. Kliegman, Ann M. Arvin; senior editor, Waldo E. Nelson – 15th ed. – W.B.Saunders Company, 1996. – 2200 p.

    2. Nursing care of Infants and Children / editor Lucille F. Whaley and I. Wong, Donna L. – 2nd ed. – The C.V.Mosby Company. – 1983. – 1680 p.


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