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#[[endoderm]]
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Na kraju [[pregnancy]], the [[fetus]] must take the journey of [[childbirth]] to leave the [[reproductive]] [[female]] mother. Upon its entry to the air-breathing world, the [[newborn]] must begin to adjust to life outside the [[uterus]].
'''Ektoderm''' (grč. ''ektos'' - "van" i ''derma'' "koža")<ref name="GilbertScott">Gilbert, Scott F. Developmental Biology. 9th ed. Sunderland, MA: Sinauer Associates, 2010: 333-370. Print.</ref> je vanjski [[zametni listići|zametni listić]] [[gastrula|gastrule]] svih višestaničnih životinja. Druga dva sloja su [[mezoderm]] (srednji sloj) i [[endoderm]] (unutrašnji sloj).<ref>Langman's Medical Embryology, 11th edition. 2010.</ref> Nastaje iz vanjskog sloja zametnih stanica.


==Breathing and circulation==
Općenito govoreći, ektoderm se diferencira kako bi nastali [[živčani sustav]] (kralježnica, periferni živci i mozak),<ref>http://www.bioethics.gov/reports/stemcell/glossary.html</ref><ref name="simple">http://simple.wikipedia.7val.com/wiki/Mate</ref> zubna [[caklina]] i [[pousmina]] (vanjski dio [[pokrovni sustav|pokrovnog sustava]]). Iz ektoderma se također formira, anus, nostrils, sweat glands, hair and nails.<ref name="simple"/>
Perfusing its body by [[breath]]ing independently instead of utilizing [[placenta]]l [[oxygen]] is the first challenge of a newborn. At birth, the baby's lungs are filled with lung liquid. The newborn is expelled from the birth canal, its central nervous system reacts to the sudden change in temperature and environment.<ref name=about/> This triggers it to take the first breath, within about 10 seconds after delivery.<ref name=about>[http://adam.about.com/encyclopedia/Changes-in-the-newborn-at-birth.htm About.com > Changes in the newborn at birth] Review Date: 27 November 2007. Reviewed By: Deirdre OReilly, MD</ref> With the first breaths, there is a fall in [[pulmonary vascular resistance]], and an increase in the surface area available for [[gas exchange]]. Over the next 30 seconds the pulmonary blood flow increases and is oxygenated as it flows through the alveoli of the lungs. Oxygenated blood now reaches the left atrium and ventricle, and through the descending aorta reaches the umbilical arteries. Oxygenated blood now stimulates constriction of the umbilical arteries resulting in a reduction in placental blood flow. As the pulmonary circulation increases there is an equivalent reduction in the placental blood flow which normally ceases completely after about three minutes. These two changes result in a rapid redirection of blood flow into the [[Pulmonary blood flow|pulmonary vascular]] bed, from approximately 4% to 100% of [[cardiac output]]. The increase in pulmonary [[vein|venous]] return results in [[left atrium|left atrial]] pressure being slightly higher than right atrial pressure, which closes the ''[[foramen ovale (heart)|foramen ovale]]''. The flow pattern changes results in a drop in blood flow across the ''[[ductus arteriosus]]'' and the higher blood oxygen content of blood within the aorta stimulates the constriction and ultimately the closure of this [[Fetus#Circulatory system|fetal circulatory]] shunt.


All of these [[cardiovascular system]] changes result in the adaptation from fetal circulation patterns to an [[adult]] [[Circulatory system|circulation]] pattern. During this transition, some types of congenital heart disease that were not symptomatic ''[[in utero]]'' during fetal circulation will present with [[cyanosis]] or [[Respiration (physiology)|respiratory]] signs.
Kod [[kralježnjaci|kralježnjaka]] ektoderm se sastoji od tri dijela: [[površinski ektoderm]], [[neuralni greben]] i [[neuralna cijev]]. Neuralni greben i neuralna cijev poznati su pod zajedničkim nazivom [[neuroektoderm]].
[[File:Postnatal genetics en.svg|thumb|300px|Changing the composition of hemoglobin before and after birth. Also identifies the types of cells and organs in which the gene expression (data on ''Wood W.G.'', (1976). '''Br. Med. Bull. 32, 282.''')]]


It is common obstetric practice to intervene in these changes by applying a clamp to the umbilical cord, often within 20 seconds of birth, before transition has taken place. However delayed clamping(>1min) may have benefits in terms of iron status.<ref>{{cite journal|last=Anderson|first=O|title=Effect of delayed versus early umbilical cord clamping on neonatal outcomes and iron status at 4 months: a randomised controlled trial|journal=BMJ|date=15 November 2011|volume=343|doi=10.1136/bmj.d7157|url=http://www.bmj.com/content/343/bmj.d7157}}</ref>
⚫
== Povijest ==
Ruski biolog [[Heinz Christian Pander]] je zaslužan za otkriće triju [[zametni listići|zametnih listića]] koji se stvaraju tijekom [[embriogeneza|emgriogeneze]]. Pander je dobio doktorat iz [[zoologija|zoologije]] na Sveučilištu u Wurzburgu 1817. Započeo je izučavanja u embriologiji koristeći kokošja jaja, zahvaljujući kojima je otkrio ektoderm, [[mezoderm]] i [[endoderm]]. Zbog ovih otkrića, Pander se ponekad naziva "utemeljiteljem embriologije". Panderov rad na ranim zamecima nastavio je prusko-estonski biolog [[Karl Ernst von Baer]], koji je istraživao zametne listiće kod različitih vrsta te tako proširio ovo načelo na sve kralježnjake. Baer je također zaslužan za otkriće [[blastula|blastule]]. Svoja saznanja, uključujući i teoriju o zametnim listićima, objavio je u udžbeniku ''O povijesti razvoja životinja'', koji je objavljen 1828.<ref>Baer KE von (1986) In: Oppenheimer J (ed.) and Schneider H (transl.), Autobiography of Dr. Karl Ernst von Baer. Canton, MA: Science History Publications.</ref>


Following birth, the expression and re-uptake of [[surfactant]], which begins to be produced by the fetus at 20 weeks gestation, is accelerated. Expression of surfactant into the alveoli is necessary to prevent alveolar closure ([[atelectasis]]). At this point, rhythmic breathing movements also commence. If there are any problems with breathing, management can include stimulation, [[bag and mask ventilation]], [[intubation]] and [[ventilation (physiology)|ventilation]]. Cardiorespiratory monitoring is essential to keeping track of potential problems.
== Diferencijacija ==
[[Pharmacological]] therapy such as [[caffeine]] can also be given to treat [[apnea]] in premature newborns. A positive airway pressure should be maintained, and [[neonatal sepsis]] must be ruled out.
=== Početna pojava ===
Na početku procesa [[gastrulacija|gastrulacije]], [[zametak]] se sastoji od velikog broja stanica. Ima oblik šuplje kugle i naziva se [[blastula]]. Dijeli se na dva dijela: životinjsku i biljnu hemisferu. Iz životinjske hemisfere kasnije se razvije ektoderm.<ref name="GilbertScott" />


Potential neonatal respiratory problems include [[apnea]], [[transient tachypnea of the newborn]] (TTNB), [[Infant respiratory distress syndrome|respiratory distress syndrome]] (RDS), [[meconium aspiration syndrome]] (MAS), [[airway obstruction]], and [[pneumonia]].
=== Rani razvoj ===
Kao i druga dva zametna listića, mezoderm i endoderm, ektoderm se formira nedugo nakon što je oplođena jajna stanica i započeta brza dioba stanica. [[Epiderma]] [[koža|kože]] potječe iz dorzalnog ektoderma koji okružuje [[neuroektoderm]] u ranom stadiju gastrule. Položaj the ektoderma u odnosu na druge zametne listiće povezan je sa "selektivnim afinitetom", što znači da unutarnja površina ektoderma ima jak afinitet prema mezodermu i slab afinitet prema endodermu. Ovaj selektivni afinitet mijenja se tijekom različitih razdoblja razvoja. Snaga privlačenja između površina dvaju zametnih slojeva je određena količinom i vrstom molekula [[kaderin]]a, bjelančevina koje se nalaze u staničnoj membrani. Na primjer, [[N-kaderin]] je presudan u razdvajanju prethodnica živčanih stanica od prethodnica epitelnih stanica.<ref name="GilbertScott" /> The ectoderm is instructed to become the nervous system by the [[notochord]], which is typically positioned above it.<ref name="GilbertScott" />


==Energy metabolism==
==== Gastrulacija ====
Energy metabolism in the fetus must be converted from a continuous placental supply of [[glucose]] to intermittent feeding. While the fetus is dependent on maternal glucose as the main source of energy, it can use [[lactic acid|lactate]], free-fatty acids, and ketone bodies under some conditions. Plasma glucose is maintained by [[glycogenolysis]].
Tijekom procesa gastrulacije, posebna vrsta stanica zvanih [[Apical constriction#Bottle cells|bottle cells]] uvlači se u rupu na površini blastule koja se naziva leđnim rubom [[blastopora|blastopore]]. Once this lip has been established, the bottle cells will extend inward and migrate along the inner wall of the blastula known as the roof of the [[Blastocoele|blastocoel]]. The once superficial cells of the animal pole are destined to become the cells of the middle germ layer called the mesoderm. Through the process of radial extension, cells of the [[Polarity in embryogenesis|animal pole]] that were once several layers thick divide to from a thin layer. At the same time, when this thin layer of dividing cells reaches the dorsal lip of the [[blastopore]], another process occurs termed [[convergent extension]]. During convergent extension, cells that approach the lip intercalate mediolaterally, in such a way that cells are pulled over the lip and inside the embryo. These two processes allow for the prospective mesoderm cells to be placed between the ectoderm and the endoderm. Once [[convergent extension]] and radial intercalation are underway, the rest of the [[Polarity in embryogenesis|vegetal pole]], which will become endoderm cells, is completely engulfed by the prospective ectoderm, as these top cells undergo [[epiboly]], where the ectoderm cells divide in a way to form one layer. This creates a uniform embryo composed of the three germ layers in their respective positions.<ref name="GilbertScott" />


[[Glycogen synthesis]] in the [[liver]] and [[muscle]] begins in the late [[second trimester]] of pregnancy, and storage is completed in the [[third trimester]]. [[Glycogen]] stores are maximal at term, but even then, the fetus only has enough glycogen available to meet energy needs for 8–10 hours, which can be depleted even more quickly if demand is high. Newborns will then rely on [[gluconeogenesis]] for energy, which requires integration, and is normal at 2–4 days of life.
=== Kasniji razvoj ===
Once there is an [[embryo]] with three established germ layers, [[Cellular differentiation|differentiation]] among these three layers proceeds. The next event that will take place within the ectoderm is the process of [[neurulation]], which results in the formation of the [[neural tube]], [[neural crest]] cells and the epidermis (skin)|epidermis. It is these three components of the ectoderm that will each give rise to a particular set of cells. The [[neural tube]] cells will become the [[central nervous system]], neural crest cells will become the central nervous system, along with [[melanocytes]], facial [[cartilage]] and the [[dentin]] of [[teeth]], and the epidermal cell region will give rise to epidermis, hair, nails, sebaceous glands, [[olfaction|olfactory]] and mouth epithelium, as well as eyes.<ref name="GilbertScott" />


Fat stores are the largest storage source of energy. At 27 weeks gestation, only 1% of a fetus' body weight is fat. At 40 weeks, that number increases to 16%. Inadequate available [[glucose]] substrate can lead to [[hypoglycemia]], [[fetal growth restriction]], [[preterm delivery]], or other problems. Similarly, excess substrate can lead to problems, such as [[infant of a diabetic mother]] (IDM), [[hypothermia]] or neonatal sepsis.
==== Neurulacija ====
[[Neurulacija]] proceeds by primary and secondary neurulation, both positioning neural crest cells between a superficial epidermal layer and a deep neural tube. During primary neurulation, the notochord cells of the mesoderm signal the adjacent, superficial ectoderm cells to reposition themselves in a columnar pattern to form cells of the ectodermal [[neural plate]].<ref>O'Rahilly R, Müller F. Neurulation in the normal human embryo. Ciba Found Symp. 1994;181:70-82; discussion 82-9. Review. PubMed PMID 8005032.forabettalorretta 21:18, 19 March 2013</ref> As the cells continue to elongate, a group of cells immediately above the [[notochord]] change their shape, forming a wedge in the ectodermal region. These special cells are called [[medial hinge cells]] (MHP). Now, as the ectoderm continues to elongate, the ectodermal cells of the neural plate fold inward. The inward folding of the ectoderm by virtue of mainly cell division continues until another group of cells form within the neural plate. These cells are termed [[dorsolateral hinge cells]] (DLHP), and once formed, the inward folding of the ectoderm stops. The [[dorsolateral hinge cells|DLHP cells]] function in a similar fashion as [[medial lateral cells|MHP cells]] regarding their wedge like shape, however, the DLHP cells result in the ectoderm converging. This convergence is led by ectodermal cells above the DLHP cells known as the neural crest. The neural crest cells eventually pull the adjacent ectodermal cells together, which leaves neural crest cells between the prospective [[epidermis (skin)|epidermis]] and hollow, neural tube.<ref name="GilbertScott" />


Anticipating potential problems is the key to managing most neonatal problems of energy metabolism.
==== Organogeneza ====
For example, early feeding in the delivery room or as soon as possible may prevent hypoglycemia.
If the [[blood glucose]] is still low, then an [[intravenous]] (IV) bolus of glucose may be delivered, with continuous infusion if necessary. Rarely, [[steroid]]s or [[glucagon]] may have to be employed.


==Temperature regulation==
[[datoteka:EctodermalSpecification.png|thumb|Ektodermalna specifikacija]]
Newborns come from a warm environment to the cold and fluctuating temperatures of this world.
Svi organi koji nastaju iz ektoderma, kao što su živčani sustav, kosa, zubi i mnoge žlijezde s vanjskim izlučivanjem, potječu od dva susjedn sloja tkiva: epitel i mezenhim.
They are naked, wet, and have a large surface area to mass ratio, with variable amounts of [[Thermal insulation|insulation]], limited metabolic reserves, and a decreased ability to [[shiver]]. Physiologic mechanisms for preserving core temperature include vasoconstriction (decrease blood flow to the skin), maintaining the fetal position (decrease the surface area exposed to the environment), jittery large muscle activity (generate muscular heat), and "non-shivering thermogenesis". The latter occurs in [[Brown adipose tissue|"brown fat"]] which is specialized adipose tissue with a high concentration of mitochondria designed to rapidly oxidize fatty acids in order to generate metabolic heat. The newborn capacity to maintain these mechanisms is limited, especially in premature infants. As such, it is not surprising that some newborns may have problems regulating their [[temperature]].
<ref>{{cite journal|last=Pispa|first=J|coauthors=Thesleff, I|title=Mechanisms of ectodermal organogenesis.|journal=Developmental biology|date=Oct 15, 2003|volume=262|issue=2|pages=195–205|doi=10.1016/S0012-1606(03)00325-7|pmid=14550785}}</ref>Nekoliko tvari su posrednici [[organogeneza|organogeneze]] ektoderma: [[faktor rasta fibroblasta|FGF]], [[transformirajući faktor rasta beta|TGFβ]], signalni protein Wnt i regulatori iz porodice Hedgehog. Vrijeme u kojem nastaju organi iz ektoderma ovisi o invaginaciji epitelnih stanica.<ref name="ReferenceA">{{cite doi|10.1186/1478-811X-10-34}}</ref> FGF-9 je važan čimbenik u početku razvoja zubnih slojeva. Brzina epitelne invaginacije je značajno povećana djelovanjem FGF-9, koji se izlučuje samo u epitelu, a ne u mezenhimu. FGF-10 potpomaže stimulaciju diobe epitelnih stanica, kako bi se napravili veći zubni slojevi. Zubi sisavaca razvijaju se iz ektoderma izvedenog iz mezenhima: usni ektoderm i neuralni greben.
As early as the 1880s, infant [[wikt:incubator|incubator]]s were used to help newborns maintain warmth, with humidified incubators being used as early as the 1930s.


Basic techniques for keeping newborns warm include keeping them dry, wrapping them in blankets, giving them hats and clothing, or increasing the ambient temperature. More advanced techniques include incubators (at 36.5°C), [[humidity]], heat shields, thermal blankets, double-walled incubators, and radiant warmers while the use of skin-to-skin "kangaroo mother care" interventions for low birth-weight infants have started to spread world-wide after its use as a solution in developing countries.<ref>http://onlinelibrary.wiley.com/doi/10.1111/j.1365-3148.2007.00812.x/abstract?userIsAuthenticated=false&deniedAccessCustomisedMessage=</ref>
== Klinička važnost ==
=== Ektodermalna displazija ===
[[Ectodermalna displazija]] je rijetko, ali ozbiljno stanje u kojem se skupine tkiva (posebno zubi, koža, kosa, nokti i znojne žlijezde) nastale iz ektoderm nenormalno razvijaju. Ektodermalna displazija je nejasan pojam, budući da podstoji preko 170 podvrsta ektodermalne displazije.Prihvaćeno je da je bolest uzrokovana mutacijom ili kombinacijom mutacija u broju gena. Istraživanje bolesti se nastavlja, budući da je otkriven samo dijelić mutacija umiješanih u podvrste ove bolesti.<ref>{{cite journal|last=Priolo|first=M.|coauthors=Laganà, C|title=Ectodermal Dysplasias: A New Clinical-Genetic Classification|journal=Journal of Medical Genetics|date=September 2001|volume=38|issue=9|pages=579–585|doi=10.1136/jmg.38.9.579|pmid=11546825}}</ref>


[[datoteka:HED.jpg|thumb|zubne abnormalnosti u petogodišnje djevojčice iz sjeverne Švedske, koja je imala različite simptome autosomalne dominantne hipohidrotične ektodermalne displazije (HED) a) Intraoralni pogled. Gornji sjekutići su obnovljeni mješavinom materijala da se prekrije njihov prvotni stožasti oblik. b) Ortopantomogram prikazuje odsutnost deset mliječnih i jedanaest trajnih zubi u čeljusti iste djevojčice.]]


⚫
== Izvori ==
[[Hipohidrotička ektodermalna displazija]] (HED) je najčešća podvrsta ove bolesti. Klinički slučajevi pacijenata s ovim stanjem pokazuju niz simptoma. Jedna od najčešćih abnormalnosti je [[hipohidroza]] ili nemogućnost znojenja, koja se može pripisati disfunkciji znojnih žlijezda. To može biti posebno opasno u toplim klimama gdje pacijenti mogu dobiti [[toplinski udar]]. S ovim poremećajem su povezane i različite malformacije lica, kao što je nepravilan oblik ili odsutnost zubi, naborana koža oko očiju, nepravilan oblik nosa, kao i rijetka i tanka kosa. Kožni problemi, kao što je [[dermatitis]] su se također pojavljivali u nekim slučajevima.<ref>Clarke, A., D. I. Phillips, R. Brown, and P. S. Harper. "Clinical Aspects of X-linked Hypohidrotic Ectodermal Dysplasia." Archives of Disease in Childhood 62.10 (1987): 989-96. Print.</ref> Ova bolest uglavnom napada mušku djecu jer imaju samo jedan [[X chromosome]], što znači da je jedna kopija mutiranog gena dovoljna da izazove nenormalan razvoj. Kod ženskog spola, oba X kromosoma bi trebala nositi gensku mutaciju. Ako žena ima mutiranu verziju gena na jednom od X kromosoma, ona se smatra nositeljem bolesti.

== izvori ==
{{izvori}}
{{izvori}}


== Vanjske poveznice ==
{{embriologija}}
*[http://adam.about.com/encyclopedia/Changes-in-the-newborn-at-birth.htm About.com > Promjene kod novorođenčeta pri rođenju]
{{Čovječji stanični tipovi primarno derivirani od ektoderma}}


<nowiki>[[Kategorija:ginekologija i porodništvo]]</nowiki>
<!-- [[kategorija:razvojna biologija]]
[[kategorija:embriologija]] -->

Inačica od 19. prosinca 2014. u 18:46

Embriologija

  1. zona pellucida
  2. zametni listići
  3. ektoderm
  4. mezoderm
  5. endoderm
  6. humana embriogeneza
  7. unutarnja stanična masa
  8. metamerija
  9. fetalni krvotok

Neonatologija

  1. neonatologija
  2. prilagodba na izvanmaternični život
  3. mekonijski aspiracijski sindrom
  4. sirasti maz
  5. vještičje mlijeko
  6. fetusni hidrops
  7. hemolitička bolest novorođenčadi
  8. kernikterus
  9. nekrotizirajući enterokolitis
  10. neonatalne akne
  11. prijevremeni porod
  12. neonatalna sepsa
  13. neonatalni konjunktivitis
  14. sindrom sivog djeteta
  15. neonatalna žutica
  16. neonatalni meningitis
  17. neonatalni zubi
  18. neonatalni tetanus
  19. neonatalni moždani udar
  20. mrtvorođenče

Na kraju pregnancy, the fetus must take the journey of childbirth to leave the reproductive female mother. Upon its entry to the air-breathing world, the newborn must begin to adjust to life outside the uterus.

Breathing and circulation

Perfusing its body by breathing independently instead of utilizing placental oxygen is the first challenge of a newborn. At birth, the baby's lungs are filled with lung liquid. The newborn is expelled from the birth canal, its central nervous system reacts to the sudden change in temperature and environment.[1] This triggers it to take the first breath, within about 10 seconds after delivery.[1] With the first breaths, there is a fall in pulmonary vascular resistance, and an increase in the surface area available for gas exchange. Over the next 30 seconds the pulmonary blood flow increases and is oxygenated as it flows through the alveoli of the lungs. Oxygenated blood now reaches the left atrium and ventricle, and through the descending aorta reaches the umbilical arteries. Oxygenated blood now stimulates constriction of the umbilical arteries resulting in a reduction in placental blood flow. As the pulmonary circulation increases there is an equivalent reduction in the placental blood flow which normally ceases completely after about three minutes. These two changes result in a rapid redirection of blood flow into the pulmonary vascular bed, from approximately 4% to 100% of cardiac output. The increase in pulmonary venous return results in left atrial pressure being slightly higher than right atrial pressure, which closes the foramen ovale. The flow pattern changes results in a drop in blood flow across the ductus arteriosus and the higher blood oxygen content of blood within the aorta stimulates the constriction and ultimately the closure of this fetal circulatory shunt.

All of these cardiovascular system changes result in the adaptation from fetal circulation patterns to an adult circulation pattern. During this transition, some types of congenital heart disease that were not symptomatic in utero during fetal circulation will present with cyanosis or respiratory signs.

Changing the composition of hemoglobin before and after birth. Also identifies the types of cells and organs in which the gene expression (data on Wood W.G., (1976). Br. Med. Bull. 32, 282.)

It is common obstetric practice to intervene in these changes by applying a clamp to the umbilical cord, often within 20 seconds of birth, before transition has taken place. However delayed clamping(>1min) may have benefits in terms of iron status.[2]

Following birth, the expression and re-uptake of surfactant, which begins to be produced by the fetus at 20 weeks gestation, is accelerated. Expression of surfactant into the alveoli is necessary to prevent alveolar closure (atelectasis). At this point, rhythmic breathing movements also commence. If there are any problems with breathing, management can include stimulation, bag and mask ventilation, intubation and ventilation. Cardiorespiratory monitoring is essential to keeping track of potential problems. Pharmacological therapy such as caffeine can also be given to treat apnea in premature newborns. A positive airway pressure should be maintained, and neonatal sepsis must be ruled out.

Potential neonatal respiratory problems include apnea, transient tachypnea of the newborn (TTNB), respiratory distress syndrome (RDS), meconium aspiration syndrome (MAS), airway obstruction, and pneumonia.

Energy metabolism

Energy metabolism in the fetus must be converted from a continuous placental supply of glucose to intermittent feeding. While the fetus is dependent on maternal glucose as the main source of energy, it can use lactate, free-fatty acids, and ketone bodies under some conditions. Plasma glucose is maintained by glycogenolysis.

Glycogen synthesis in the liver and muscle begins in the late second trimester of pregnancy, and storage is completed in the third trimester. Glycogen stores are maximal at term, but even then, the fetus only has enough glycogen available to meet energy needs for 8–10 hours, which can be depleted even more quickly if demand is high. Newborns will then rely on gluconeogenesis for energy, which requires integration, and is normal at 2–4 days of life.

Fat stores are the largest storage source of energy. At 27 weeks gestation, only 1% of a fetus' body weight is fat. At 40 weeks, that number increases to 16%. Inadequate available glucose substrate can lead to hypoglycemia, fetal growth restriction, preterm delivery, or other problems. Similarly, excess substrate can lead to problems, such as infant of a diabetic mother (IDM), hypothermia or neonatal sepsis.

Anticipating potential problems is the key to managing most neonatal problems of energy metabolism. For example, early feeding in the delivery room or as soon as possible may prevent hypoglycemia. If the blood glucose is still low, then an intravenous (IV) bolus of glucose may be delivered, with continuous infusion if necessary. Rarely, steroids or glucagon may have to be employed.

Temperature regulation

Newborns come from a warm environment to the cold and fluctuating temperatures of this world. They are naked, wet, and have a large surface area to mass ratio, with variable amounts of insulation, limited metabolic reserves, and a decreased ability to shiver. Physiologic mechanisms for preserving core temperature include vasoconstriction (decrease blood flow to the skin), maintaining the fetal position (decrease the surface area exposed to the environment), jittery large muscle activity (generate muscular heat), and "non-shivering thermogenesis". The latter occurs in "brown fat" which is specialized adipose tissue with a high concentration of mitochondria designed to rapidly oxidize fatty acids in order to generate metabolic heat. The newborn capacity to maintain these mechanisms is limited, especially in premature infants. As such, it is not surprising that some newborns may have problems regulating their temperature. As early as the 1880s, infant incubators were used to help newborns maintain warmth, with humidified incubators being used as early as the 1930s.

Basic techniques for keeping newborns warm include keeping them dry, wrapping them in blankets, giving them hats and clothing, or increasing the ambient temperature. More advanced techniques include incubators (at 36.5°C), humidity, heat shields, thermal blankets, double-walled incubators, and radiant warmers while the use of skin-to-skin "kangaroo mother care" interventions for low birth-weight infants have started to spread world-wide after its use as a solution in developing countries.[3]


Izvori

  1. ↑ a b About.com > Changes in the newborn at birth Review Date: 27 November 2007. Reviewed By: Deirdre OReilly, MD
  2. ↑ Anderson, O. 15. studenoga 2011. Effect of delayed versus early umbilical cord clamping on neonatal outcomes and iron status at 4 months: a randomised controlled trial. BMJ. 343. doi:10.1136/bmj.d7157
  3. ↑ http://onlinelibrary.wiley.com/doi/10.1111/j.1365-3148.2007.00812.x/abstract?userIsAuthenticated=false&deniedAccessCustomisedMessage=

Vanjske poveznice

[[Kategorija:ginekologija i porodništvo]]

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