Independent work of students on the theme: " Age characteristics of the normal

the normal physiology of the respiratory system."

Prepared by: Kosimov E.I.
Student: about OM 36-1
Course: III
Checked: Shaikhynbekova R.M.

Almaty,2016

breathing infants.
Age-related changes in breathing.
lung ventilation.
Conclusion.
References.

are -Easy.
In children, respiratory system has specific features inherent to

their age.

Introduction.

(adult - 1 kg).
Acini differentiated enough. During postnatal development formed

alveolar ducts with typical alveoli.
Lungs filled prior to liquid ventilation, the amount of which (on average 100 ml) is close to the magnitude of functional residual capacity (FRC), after 2 days after birth.

are:
superficial breathing;
physiological dyspnea (tachypnea);
often abnormal rhythm of respiration;
intensity of gas

exchange processes;
easy occurrence of respiratory failure.

the state of the respiratory center, leading to the beginning

of ventilation.
The first breath occurs, usually after 15 to 70 seconds after birth, usually - after clamping of the umbilical cord, but sometimes - before him, ie, immediately after birth.
The main condition for the appearance of the first inspiration is the presence in the blood of humoral stimuli breathing.
These include CO2, H +, and O2 deficiency. In the process of giving birth, and especially after the ligation of the umbilical cord, the tension of CO2 and H + concentration increases, increased hypoxia (the state of asphyxia).

sharp increase in the flow of afferent impulses from skin

receptors (tactile and cold), proprioceptor are, vestibuloocular occurring during childbirth and immediately after birth.
These pulses activate the reticular formation of the brain stem, which increases the excitability of neurons of the respiratory center.
A third factor contributing to the emergence of the first breath, is the elimination of sources of inhibition of the respiratory center. Thus, the fluid irritation of receptors located in the region of the nostrils, strongly inhibits the breathing reflex of a diver").
Therefore, immediately after emergence from the birth canal, the fetal head, the obstetrician removed from the face mucus and amniotic fluid, and sometimes suck the liquid out of the Airways.
Thus, the occurrence of the first breath is the result of simultaneous action of several factors, the relative importance of which is not yet fully understood.

strong excitation of the inspiratory muscles to inhale primarily the

diaphragm.
In 85% of cases first breath deeper than the next, the respiratory cycle is longer.
The duration of the first breath of 0.1—0.4 C. The volume of air inhaled is usually 20-80 ml. feature of the first respiratory cycle is a great time of exhalation (average of 3.8).
First exhale, as a rule, is active: it is accompanied by contraction of expiratory muscles. Within the pleural pressure during the first exhalation becomes positive, reaching on average 35 cm of water. art (from 0 to 70 cm of water. calendar).

scream.
During the first exhalation the child breathes on average

24 ml (16 to 30 ml). A smaller amount of exhaled air compared to inhaled provides the beginning of the formation of the FRC.

lungs of the child is from 4 to 50 ml

(sometimes up to 80 ml) of air. Further, FRC is increased from breath to breath. For the first 10-20 minutes it reaches about 75 ml. Aeration of the lungs usually ends for 2-4-th day after birth. At this age, FRC is about 100 ml. The formation of the FRC, accompanied by the removal from the alveoli of fluid. Part of it is squeezed out during birth during passage of the fetus through the birth canal (when intrathoracic pressure may increase to 74— 95 cm water. calendar). In children, extracted by caesarean section, in the lungs more liquid than those born naturally, therefore, aeration of the lungs they needed more time. During the first breath the fluid from Airways enters the alveoli. of the lung fluid is removed at the first exhalation through the upper airway.

to the shape of the cone. The ribs are arranged

at a large angle to the spine (with smaller slope) than adults, so reducing the intercostal muscles less efficiently change the volume of the chest cavity.
Quiet breathing in neonates is diaphragmatic. But when you cry dyspnea inspiratory intercostal muscles help to increase thoracic cavity. Newborns always breathe by nose.
Small body size of newborns largely determine the properties of the apparatus of external respiration. A small absolute value of FRC (about 100 ml) requires a high breathing frequency and small magnitude, tidal volume, or the composition of the alveolar air much would change during the respiratory cycle.

The position of edges (circuit) of a newborn child (1 ) and the adult (2 ). The scale sizes are not met.

min, an average of about 40 in 1 min (adult—

12— 18 in 1 min).
Tidal volume (VT) in neonates on average about 17 ml (10 to 25 ml), adults, 400-500 ml.
The volume of dead (Vd) space in newborns (4 to 6 ml), as in adults, 25-30% of tidal volume. Respectively, for 1 breath is exchanged 6 to 19 ml of alveolar air.

1 — the beginning of the first breath, visible boundary of air and fluid in the trachea; 2 the end of the first inhalation, the liquid is in part of the alveoli. Shading point — pulmonary fluid.

— 14 days £ 500 and 900 ml / min-1

(in adults alone — 6-9 l - min"').
The magnitude of alveolar ventilation in newborns — 400-500 ml/ min-1 (adult — 5—6L - min"1) . Vital capacity (VC) in newborns is estimated according to the volume of air exhaled in the creek.
VC creek in newborns is 120— 150 ml (34-43 ml-kg-1 ). VC adults — 3000-5000 ml (40-67 m l-kg"1). Inspiratory reserve volume in neonates is about 54%
VC (in adults — 66% ), reserve volume exhalation — 34% (in adults — 23% ). Thus, for newborns characterized by a relatively small reserve volume.

birth, contributes to a large oxygen capacity of the blood

— 210-260 ml O2-l~ (in adults -190 ml O2*l-1 ) due to the high content of hemoglobin in the blood.
To 2-3 weeks due to the decrease in the amount of hemoglobin LOC decreases (to an average of About 144 ml).
Thus, for neonates is less than in adults, the degree of saturation of hemoglobin with oxygen, a large oxygen capacity of the blood (with subsequent reduction), greater oxygen consumption per unit mass, a decrease in pH. blood immediately after birth (increased metabolic acidosis) with subsequent compensation of this condition. 

of gas diffusing per unit of differential partial pressure) in

children is naturally lower than in adults. The increase in diffusion capacity caused by increase of surface of pulmonary membrane, but the rate of diffusion of gases through a unit of surface of pulmonary membrane changes little with age (Z-4 ml\min).

ventilation is determined by the frequency and depth of breathing.
Minute

ventilation (VL) or respiratory minute volume (Ve) alone increases with age almost 10 times.
The most intensive growth of Ve occurs at the 1st year after birth. In the future, the Ve increases more gradually, especially slowly from 7-8 to 10-11 years of age.
In puberty growth accelerated again Ve. In 14 of 18 Ve may be a little higher than in adults. For children with high levels of ventilation per unit of body weight (relative DEM).
With age, the relative Ve decreases as body mass increases stronger (approximately 20 times) than the Ve. Decreases the intensity of the pulmonary ventilation is slow to 5-6 years,and then significantly accelerated to 11 — 12 years.
In puberty the relative reduction Ve is slowed down again, continuing until approximately 20 years, after which it is stabilized.

the 1st year after birth. In the future, the respiratory rate

decreases more gradually to 18-20 years.
Respiratory cycles are lengthened due to how the inspiratory phase and the exhalation.
For children in the first years is characterized by the irregularity of the respiratory rhythm. With age, the rhythm of breathing becomes more stable. But in adolescence the rhythm of breathing less resistant than adults.
In children the duration of inhalation and exhalation is close (in adults exhale longer than inhale). Increasing the length of exhalation relative to inhalation in some people occurs during adolescence, the part — later.
Depth of breathing . Increased depth of breathing is the respiratory volume (VT). Tidal volume increases approximately linearly from age.

ventilation by the amount of ventilation of the dead space.

The volume of dead space increases with age (from newborn to 4-5 ml, adults 150— 170 ml), but the ratio of dead space volume to tidal volume changes little.
In this regard, the alveolar ventilation in children, as in adults, 25-30% less Ve.

of its components strongly increase with age. Of particular importance

is the increase with age of the functional residual capacity (FRC).
During inhalation, FRC is added to the alveolar part of tidal volume. The volume of alveolar air at the end of the breath is called the functional capacity of the lungs (FCL).
Constituting the FRC and FCL, — internal gas environment of the body, which are important: the FRC contains a supply of oxygen, from R CO2 depends on the CO2 tension in arterial blood, the FRC smooths out changes in the composition of the alveolar air during inhalation and exhalation, the alveolar air is saturated with water vapor, eliminating the drying of the walls of the alveoli, the air is body temperature.
The ratio of the alveolar part UP to the FRC (ratio ventilation) during quiet breathing rather remains stable as the growth of children (13— 17%, FRC).

7— 11 years old is still a conical-shaped rib cage

with a relatively small inclination of the ribs. In adolescents thorax becomes similar to the cylinder, increases the slope of edges, increases the strength of respiratory muscles.
These factors provide increasing of the reserve volume of inhalation and exhalation. Thus, for children characterized by high elastic and nonelastic breathing resistance.
Therefore, the breathing muscles (mostly inspiratory) spend on mechanical ventilation is relatively a lot of energy.

in adults, due to the rich vascularization of the lungs,

blood flow velocity, high diffusion capacity. At the same time the function of external respiration in a young child is disturbed very quickly due to lack of excursions of the lungs and straightening of the alveoli. We should not forget that the child is not a smaller version of the adult, so the structure and functioning of the respiratory system has its own specific features.