PEDIATRIC´S PHYSIOLOGY Physiological peculiarities in children This lecture is one of the first on information about the child's physiology. From a medical point of view, a child cannot be seen as a miniature of an adult. It has its peculiarities due to the development of individual organ systems and their functions. And it is these peculiarities that we will talk about - in the lecture and we will continue the demonstration. GROWTH PERIODS •CHILDREN üNewborn: 0 –28 days after born (1 month)-adaptation period üSuckling: 2 – 12 month - infant intensive growth üCommon term: infancy ü1 – 4 years old ü(Toddler 1 –3 years old; speech development, development of thinking) üCommon term: early childhood Pediatricians suffer from the correct naming of individual stages of a child's development - each period has its own characteristics. GROWTH PERIODS ü5 – 12 years old – late childhood ü üOther special terms: üPre-school period 5 – 7 years üSchool period – younger, older and then the names take place according to the school environment. GROWTH PERIODS •ADOLESCENCE ü13 – 20 years old üThe other special terms: üTeenager -19 years üPubertas 11-15 years Adolescence period – started by pubertas WEIGHT •Birthweight: 2 500 - 3 800 g •Double birthweight: 4-5 mo •Triple birthweight: 1yr •Quadruple birthweight: 2 yr • •Pecularity in newborn: Weight loss in first few days : 5-10% of birthweight •Return to birthweight: 4 -7 days of age • First anthropometric parameter: Body weight – important information during whole children period ATTENTION on a special“ Physiological“ phenomenon : weight loss in the first 3 days after birth. Low food intake, fluid and stool loss lead to weight loss. Must not exceed 10% of birth weight and this is one of the reasons why mothers are allowed home with their children until about 4-5 days after birth (when a pediatrician taking care of the baby is sure that the weight loss has stopped and the baby will only gain weight without any problems). •AVERADGE weights: • at birth: 3.5 kg • at 1 yr: 10 kg • at 5 yrs: 20 kg • •DAILY weight gain – important for evaluation of nutritional state: • 20-30g for first 3-4 mo • 15-20 g for rest of the first year You can see examples of weight gaine In this slide you can see individual percentile graphs that help pediatricians determine the correct development of a child in relation to age; distinguished girls - boys. The population average ranges between the 5th-95th percentile… Gaussian curve of parameter distribution. HEIGHT •AVERADGE length: 20 in (50 cm) at birth • 30 in (75 cm) at 1 yr • at age 3 yr, the averadge child is 3 ft tall • at 4 yr, the averadge child is 40 in (100 cm) tall (double birth length) •Averadge ANNUAL length increase: 2-3 in (5-7 cm) between age 4 yr and puberty The second important anthropometric parameter: body height (in newborn known as body lenght) ..also the percentile graph for body height… HAED CIRCUMFERENCE (HC) •Averadge HC: 35 cm at birth (13.5 in) •HC increases: • 1 cm per mo for first year CHEST CIRCUMFERENCE (ChC) Averadge 33-34 cm at birth 6th month 43 cm ( HC = ChC) 1st year HC: 46-47 cm ChC: 48 cm 5th-6th year HC: 51 cm ChC: 55 cm 11th year HC: 52-53 cm ChC: 63-64cm 14th year HC: 54 cm ChC: 68 cm The third very important anthropometric parameter – special for children age: head circumference. Please, remember the value at birth – head circumference is grater than the chest circumference… is logical, given the course of parturition = the head goes first… therefore it is clear that it must have a larger circumference than the chest (if it were the other way around, the baby will get stuck in the birth canal during parturition), after half a year this relationship reverses and from at that moment, the chest is always larger than the head, an unwritten rule applies until the age of 15: that the circumference of the head is as small as the circumference of the child's age. Newborn according the weeks of gestation and birth weight •Preterm infant (premature – earlier than 38weeks of gestation) üLow birthweight infants (LBW): • less than 2 500 g üVery low birthweight (VLBW): • less than 1 500 g •Full-term infant (38 – 40 weeks of gestation) • birthweight 3 000 - 3 500 g, 48-52 cm length, head circumference 35cm •Ower-term infant (41 – 42 weeks of gestation) • 4000 - 6 000g, 53 - 56 cm This picture shows a more detailed division of the newborn age –according to weeks of gestation and body weight. 36th week 38th week 40th week week of gestation Before the era of ultrasound examinations, the estimate of the gestational week could be determined by the plantar furrows on the sole of the foot of the newborn baby - see the picture. The skin •is covered by white muzzle – vernix caseosa •after cleansing - deep red - erythema neonatorum • • another peculiarity - The skin is covered by white muzzle – vernix caseosa Picture of my granddaughter shortly after giving birth, you see skin covered with white muzzle…. …. and here already a pretty clean, washed, with a touch of red Examination of newborn at the delivary room •APGAR score •acronym or backronym: Appearance, Pulse, Grimace, Activity, Respiration • Signs Points • 0 1 2 üHeart rate: 0 <100 /min >100/min üPulse üRespiration: none weak cry vigorous cry üRespiration üMuscle tone none hypotonic-hypertonic limb flexion üActivity ü reflex irritability: none some motion cry, withdrawal üGrimace üColor of body: blue pink body, pink all over • Appearance blue extremities and here is more information about postpartum adaptation… This scoring system has existed for almost 70 years, which today helps to assign the necessary care to babies after childbirth. It was invented by Dr. Virginia Apgar in the United States in the 1950s, when it was used to predict the survival of newborns after birth. Ms. Virginia Apgar had her own postage stamp in the United States in honor of the introduction of this scoring system TRANSITION FROM FETAL TO NEONATAL PHYSIOLOGY •Specialities of fetal circulation: üPlacenta, where deoxygenated blood becomes oxygenated ü1 Umbilical vein – well-oxygenated blood ü2 Umbilical arteries – deoxygenated blood üForamen ovale üDuctus arteriosus Botalli üDuctus venosus Probably the biggest changes are in the cardiovascular and respiratory systems. This information is important for the physiology exam — although you should already have some foundation in histology. In fetal circulation - function of the umbilical vein - leads oxygenated blood, (saturation of hemoglobin by oxygen is only about 60%), umbilical arteries - lead deoxygenated blood. Foramen ovale - a short shunt between the right and left atria, the ductus arteriosus Botali - between the a. pulmonalis and the descending part of the aorta - more precisely serves for blood flow from the truncus pulmonalis to the arcus aorta before birth. Ductus venosus - is a link between the umbilical vein and the inferior vena cava, which changes to the ligamentum venosum by obliteration. Obliteration is completed by the second to third month of life. •Changes after birth: Disconnection of the placental circulation and the beginning of respiration lead to: •increase pressure in the systemic circulation •increase in alveolar pO2 •reduction of pulmonary vascular resistance •increase blood flow to the lungs •to close the ductus arteriosus (vasoconstriction) and foramen ovale (pressure changes) • The slide describes an overview of changes after birth. More precisely: due to umbilical cord rupture, about 300 ml of blood remains in the placenta and the rest of the umbilical vessels, so the amount of circulating blood in the newborn's bloodstream decreases = this is the first reason for pressure changes… because it reduces heart filling, decreases blood pressure and changes pressure conditions in the heart… still in the fetal circulation the right heart was high pressure due to the fact that the lungs were filled with water, is a higher vascular resisitence… with the first breath the lungs are aerated, resistance in the pulmonary system decreases… the pressure in the right atrium decreases, just a difference of 1 mmHg, which occurs and the flow of blood heading earlier from right to left before the foramen ovale stops, higher pressure in the left atrium presses the valvula foraminis ovalis to the septum… this happens during the first about 4 hours after birth, then the septum epithelializes and within about 1 month this change is permanent …... foramen ovale closes due to pressure changes. The reason for closure of the ductus arteriosus is a change in the partial pressure of oxygen in the junction between the lungs and the aorta; in the fetal circulation the blood saturation is only below 60%, when the lungs are aerated it suddenly increases to almost 100%, the smooth muscle of the duct is sensitive to this change, which is stimulated to constrict, this closure is also supported by high levels of prostaglandins in the fetal blood. The smooth muscle of the ductus venosus responds by vasoconstriction to a reduction in blood flow through this area after delivery, when more blood flows to the liver, which takes over all metabolic functions (unlike in the fetal circulation, where the mother's liver and fetus liver were lightly nourished) . Umbilical vessels contain all 3 types of muscle fibers - circular, longitudinal and transverse… manipulation of the child, cutting the umbilical cord we support the activation of these fibers, each activation supports the vasoconstrictive processes of these vessels. All these changes do not take place in the first minutes, but rather gradually in the first hours after birth, the short couplings obliterate and change permanently over the course of 1-2 months. RESPIRATORY SYSTEM •It plays an important role in postpartum adaptation •The onset of breathing is ensured by the interplay of a large number of stimuli from many areas •From the moment of birth to the 1t breath: 20-30s •Up to 90 second - spontaneous regular breathing In the newborn: 40-60 breaths / min, tidal volume 20 ml •Respiratory movements – started about 20 weeks of gestation - it is only a fluid exchange that fills the bronchoalveolar system: 1-2 ml amount; Ingredients: organic and inorganic substances; pH 6.4; Protein amount 30mg /100 ml; Substances with high surface activity-phospholipids • • • • • Along with the cardiovascular system, changes also occur in the respiratory system. Both of these systems are undergoing common changes called cardio-respiratory transition. The beginning of breathing is ensured by many mechanisms - see the information in the lecture on Respiratory system. Probably the strongest stimulus for its onset is a drop in temperature, tactile stimuli, the possibility of limb movement, light and more. •Surfactant secretion: üA substance normally secreted into the alveoli that decreases the surface tension of the alveolar fluid, therefore allowing the alveoli to open easily during inspiration üThe surfactant secreting cells ( the type II alveolar epithelial cells) started secretion about 20 weeks of gestation •Estimation of pulmonary maturity: • ratio Lecithin/sphingomyelin production 2:1 •Dicrease of surfactant in clinical paxis: diagnose Respiratory Distress Syndrome (RDS) • Surfactant is really an important factor for starting the respiratory system and rest breathing, which does not burden the postpartum adaptation with higher energy requirements. Today's pediatrics has a great advantage over the treatment of RDS 30 years ago - we can chemically produce a surfactant, we know its composition, so premature babies do not have to be under artificial ventilation, but it is enough to inject the necessary additional amount into their lungs. NEONATAL JAUNDICE •Bilirubin formed in the fetus can cross the placenta into the mother and be excreted through the liver of the mother •But •Immediately after birth the only means for ridding the neonate of bilirubin is through the neonate´s own liver, which for the 1st weeks has poorly functions (without any reserves), and decrease capacity for conjugating system of bilirubin and its excretion into the bile •The plasma bilirubin concentration rises during the first 3 days of life and then gradually falls back to normal as the liver becomes functional • •This condition called physiologic hyperbilirubineamia and it is associated with a mild jaundice of the infant´s skin and especially of the sclerae of its eyes The slide describes neonatal jaundice as one of the physiological peculiarities and its basic causes. The newborn has a handicap due to the increased load of decaying erythrocytes (which are no longer needed, but in fetal times they replaced the reduced Hb oxygen saturation), after birth the saturation increased so that they were no longer needed… they begin to disintegrate; on the other hand, there is immaturity of the systems in the liver to break down hemoglobin… especially bilirubin, dangerous is total unconjugated bilirubin - it is soluble in fats and can pass through cell membranes and remains in them… dangerous mainly for neurons… the entry of bilirubin into neurons irreversibly damages…. we have to prevent this, we have to monitor bilirubin levels… now easier than before, nurses have a tissue bilirubinometer… determines the bilirubin level from the skin surface, when it reaches a certain limit, then it is checked from the blood sample. Basically, every baby is slightly yellow (more than orange) from the 2nd day after birth - it is called physiological hyperbilirubinemia = icterus neonatorum = neonatal jaundice. This slide shows the principles of treatment of icterus neonatorum – blue light phototherapy This slide shows how bilirubin changes into water-soluble isomers due to the wavelength of blue light… we help the liver to synthesize a sufficient amount of glucuronyltransferase needed for conjugation of bilirubin (conjugative bilirubin is water soluble) Graph shows the level of total bilirubin and lines shows the border for risk to damage of nervous system TEMPERATURE •In utero thermoregulation of the fetus is performed by the placenta, which is as an efficient heat exchanger •Fetal temperature is higher than the mother´s temperature: about 38.5 °C •After birth, the newborn infant begins life covered by amniotic fluid and situated in a cold environment: 20-25 °C •An infant´s skin temperature may fall 0.3 °C/min and the core temperature may decline 0.1 °C/min in the delivery room • Another peculiarity is the temperature. Due to the rapid decline in the temperature of the newborn after birth, it has long been thought that the newborn belongs to the poikilothermic animals, unable to maintain its temperature. However, this decrease can again be explained by a certain handicap (see the next picture), so even a newborn as well as an adult belong to homoiothermic animals ... •Because the body surface area is large in relation to body mass, heat is readily lost from the body •The ideal environmental temperature is called as the neutral thermal environment: the ambient temperature resulting in the lowest rate of heat production and the lowest consumption of oxygen by the infants while maintaining normal body temperature •1 hour after birth: 33-34 °C •1 day after birth: 31-33 °C •1 weeks after birth: 27-33 °C Graphical expression of temperature drop This double-walled zinc bath with drain cock is such a forerunner of today's incubators. Fill with warm water…. next slide Empress Catherine the Great, Russia, 18th century survival against the russian winter We have a perfect tent in which newborns better maintain the temperature and thus have a much better chance of survival… the pictures date from the 18th century, such trays were used to improve the survival of newborns during the reign of Empress Catherine the Great, during the harsh Russian winters temperatures reached -50 degrees Celsius. Today's design of incubators to help maintain the temperature of premature babies Immune system •a main prenatal imunoglobulin = IgG: –passes through the placenta –At the birth – the same level as in mother –at birth is the same concentration as in the mother's body –gradually decreasing its concentration –in 3rd to 10th week reached the lowest values then again levels increase •IgM forms newborns aged 1-2 weeks • •IgA occurs at the age of one month, then the concentration slowly increases –(IgA is rich colostrum and breast milk) •After birth: üErythrocytes = 5-6 x 1012/l üLeukocytes = 20-22 x 10 9 /l üHemoglobin = 190 g/l •At 3 month of live: üErythrocytes = 4 x 10 12/l üLeukocytes = 10.5 x 10 9/l üHemoglobin = 110 g/l BLOOD - composition CARDIOVASCULAR SYSTEM Heart rate according age •Newborn 135-140 beat per minute •6 month 130-135 •1 year 120-125 •2 years 110-115 •5 years 98-100 •8 years 80-85 •15 years 70-76 General changes in the cardiovascular system in relation to age. Decreasing heart rate is seen due to the increasing effect of parasympathetic on the heart. Elektrocardiography •More difficult evaluation than in adult •The ECG curve is changing with respect to: –Ratio between right ventricule muscle/left ventricule muscle –Spred of activation from atrium to ventricule myocardium –repolarization – –Evaluation of ECG curve in children is nescesary made with respect to anamnesis, clinical state and laboratory view – Peculiarities to keep in mind when evaluating the ECG curve in young children. •Generally accepted: –In newborn – predominance of the right ventricule –To 3 month after birth – increase of left forces –At 2 years – right and left ventricule in equilibrium –3 years to adult – prevalence (superiority) of left ventricule Blood pressure •Immediately after birth – high blood pressure: –Stress after delivery, increase concentration of catecholamine and cortizol •After 1st day …….. 70/50 mmHg: –Open of pulmonary and intestine circulation •During pubertas: –Development of regulatory mechanism –Stimulation of external world Interesting facts about blood pressure values, the activation of the sympathetic system is more involved in the rising trend of blood pressure from birth to adult. •Newborn 80/46 mmHg 10.6/6.1 kPa •3 years 100/67 13.3/8.9 •10-11 years 111/58 14.8/7.7 •13-14 years 118/60 15.7/8.0 •The size of cuffs • •Body weight age size of cuff •1 500 g * 2.5 cm • 5 kg 3 month 4.5 cm •10 kg 15 month 6 cm •30 kg 9 year 7.5 cm •30 kg and more 10 year and more 12 cm GIT and NUTRITION •In general, the ability of the neonate to digest, absorb, and metabolize foods is not different that of the older child, with the following 3 exceptions: ü1. Secretion of pancretic amylase is deficient ü2. Absorption of fats from the gastrointestinal tract is somewhat less than that in the older child (milk with a high fat content - such as cow´s milk, is inadequately absorbed) ü3. The liver function during at least the 1st week of life, the glucose concentration in the blood is unstable and low • GIT •Intrauterine: motor, secretory and resorption activity of the GIT is low •At birth: •digestive enzymes for breast milk prepared •the structure of the mucosa is no different from that of an adult •weaker layer of muscles - susceptibility to meteorism •content of meconium in the intestine - it is possible to excrete it by the 4th day of life • •Decreased control of intestinal motility by the enteral nervous system with easy return of food to the oral cavity, imperfect sucking and swallowing, slower gastric emptying - frequent blinking and vomiting The slide shows changes in the GIT during the transition period: fetus - newborn. Remember the name of the first stool - tar or meconium. Danger of fetal hypoxia, inspiration is activated during parturition - meconium is inhaled - clinically diagnosed: meconium aspiration THEORY of AGE Elderly period • •Earlier senior: 65 - 75 years old •Middle senior: 75 - 85 years old •Late senior: above 85 years old • •The „AGING“ is programming biological process • Like childhood, old age is divided into several stages. Theory of „aging“ •„Free radicals“ • •– primary reason for aging is: damages of macromolecules and structures of cells by biochemistry reactions of free oxygen radicals •(oxygen free radicals damaging our bodies are „taxes“ that people breathe oxygen on the Earth) There are various theories of aging •Neuroendocrine theory • -This theory is based on the fact, that the secretion of hormone melatonin is reduce with age (as „youth hormone“; pineal gland – coordinates of circadian rhythms) •Gene theory •Increase a lot of mutations in the cells during all of the lifetime, the mutations are a primary cause of the aging •Theory of programming of aging is based on the idea that the function of genes is reduced in time (e.g. Apoptosis – programming death of the cells) •Theory based on the hypothesis that exist „any genetic programme“ (Hayflick 1985 – observing the families with longevity) The symptoms of aging •Reduction of function of all organ systems: • loco-motor function – as general and final, decreas of forces of sceletal muscles • reduction of capacity of the lungs, cardiac output, cardiac reserve, function of excretory system, liver, metabolism •reduction of number of neurons in the brain (central nervous system) •The other symptoms: •Changes in places of fat deposits •Changes of the skin hair •Changes in the memory – main in the short-term memory •Changes of the behavior – non-tolerance, depression Thank you for your attention „Everyone is old, depending on how he/she feels to be old“