Skip Navigation

National Geographic Society This program is distributed in the U.S. and Canada by National Geographic and EHD. [learn more]

Multilingual Illustrated DVD [Tutorial]

The Biology of Prenatal Development




IBHAYOLOJI YANGAPHAMBILI KOKUBELETHWA KOMNTWANA

.Ndebele [Sindebele (Ndebele)]


 
Download English PDF  Download Spanish PDF  Download French PDF  What is PDF?
 

The Fetal Period (8 Weeks through Birth)

Chapter 37   9 Weeks: Swallows, Sighs, and Stretches

Isikhathi se-fetus siqhubeka bekufike isikhathi sokubeletha.

By 9 weeks,ukukhotha iminwe kuyaqala begodu i-fetus ingagwinya i-amniotic fluid.

I-fetus seyiyakwazi nokubamba into ethile, ise ihloko phambili nemuva, ivule beyivale umhlathi, isikinye ilimi,ikhokhe umoya, izelule.

Imizwa esebusweni, ezandleni, nasezithendeni zeenyawo ingezwa ukuthintwa okuncani.

"Ekuphenduleni ukuthintwa okuncani esithendeni senyawo," i-fetus izakugoba inyonga nedolo begodu ingasonga izwani.

Izivalo zamehlo zivalekile.

Emphinjeni, kuthoma ukuvela izitho zephimbo kubonakalisa ukuthoma kokukhambisana kwephimbo.

Kuma-fetuses wabesifazane, isizalo siyabonakala namaseli angakakhulu wokubeletha, abizwa nge-oogonia, athoma ukuphindaphindana ngaphakathi kwesizalo.

Izitho zangasese sithoma ukubonakala njengezowesifazane noma wesilisa.

Chapter 38   10 Weeks: Rolls Eyes and Yawns, Fingernails & Fingerprints

Ukukhula phakathi kweemveke ezi 9 nezi 10 ukukhula komzimba ngaphezulu kwe-75%.

Eemvekeni ezi 10, ukusebenza kwelihlo elingaphezulu libangela ukuphenduka kwamehlo.

I-fetus iyazamula ivamise ukuvula nokuvala umlomo.

Ama-fetuses amanengi amunya umuno.

iincenye zamathumbu amancani ngaphakathi kwekaba abuyela ngaphakathi komgodi ongaphakathi kwamathumbu.

Ukuqinina kwamathambo kuyathoma emathanjeni amanengi.

Amazipho weminwe namazwani athoma ukukhula.

Imigadangiso yemino ehlukileko iyavela iimveke ezi-10 emva kokumumatha (fertilization.) Ikambiso le ingasetshenziswa Ukuhlukanisa epilweni yoke.

Chapter 39   11 Weeks: Absorbs Glucose and Water

Eemvekeni ezi-11 ipumulo nezindebe zomlomo ziphelile ukwenzeka. Njengesinye nesinye isitho somzimba, isimo sazo singashintsha kwelinye nelinye izinga lepilo yokukhula komuntu.

Amathumbu amancani athoma Ukwamukela amanzi ne-glucose edliwe yi-fetus.

Nanoma ubulili bakheka ekumumatheni, izitho zobulili ziyabonakala kwanjesi ngokuthi ngezesilisa noma zesifazane.

Chapter 40   3 to 4 Months (12 to 16 Weeks): Taste Buds, Jaw Motion, Rooting Reflex, Quickening

Phakathi kweemveke ezi-11 nezili-12, ubudisi be-fetus bayanda cishe nge 60%.

Iimveke eziyi 12 zikhomba ukuphela, Kweenyanga ezintathu zokukhulelwa.

Imizwa yangemlonyeni seyiphelele.
Ngesikhathi sokubelethwa, Imizwa yangemlonyeni izakuba selimini kwaphela naphezulu ngaphakathi emlonyeni.

Ukukhipha okungafuneki emzimbeni Kuthoma kusese ziimveke ezi 12 kuqhubeke iimveke ezi-6.

Okukhishwa kokucala ku-fetus kubizwa nge-meconium. Kunama enzymes wokugaya (digestive enzymes), amaphrotheni, namaseli afileko akhishwa lihlelo lokugaya.

Emva kwemveke ezi-12, Izitho zangaphezulu sezifike ebudeni obungalingana nezomzimba. Izitho zomzimba zangaphasi ziyakhula sezizokufikela ubude bazo.

Ngaphandle komgogodla Naphezulu kwehloko, umzimba woke we-fetus uyaphendula nawuthintwa kancani.

ukuhluka kokukhula okuya ngobulili kubonakala kokuthoma. Isibonelo, ama-fetus wesifazane abonisa ukusikinyeka komhlathi kanengi ukudlula wesilisa.

Nawufanisa nokubalekisa umzimba kwangaphambili, ukujabula komlomo kuyenzeka ukuphendukela kilokho okujabulisa umlomo nokuvuleka komlomo. Ukuphendulokhu kubizwa nge "rooting reflex" begodu kuyaqhubeka ngemva kokubelethwa, kunceda ingane ifumane ibele likamama ngesikhathi sokuncela.

Ubuso buyaqhubeka nokukhula lokha amafutha athoma ukugcwala imihlathi nokukhula kwamazinyo kuthoma.

Eemvekeni ezi-15, amaseli akha iingazi ayafika(blood-forming stem cells) aziphindaphinde ngaphakathi kwethambo. Amaseli weengazi amanengi enzakala la.

Nanoma ukukhambakhamba kuthoma Ku-embryo eneemveke ezi-6, okhulelweko uthoma ezwe ukukhambakhamba kwe-fetus hlangana kweemveke ezi-14 nezi-18. Ngokwesiko isenzeko lesi Sibizwa ukwenza msinyana (quickening).

Chapter 41   4 to 5 Months (16 to 20 Weeks): Stress Response, Vernix Caseosa, Circadian Rhythms

Eemvekeni ezi-16, ikambiso yokufakwa kwenalithi ngemathunjini we-fetus aletha ukukhathazeka kwamahomoni kukhiphe i-noradrenaline, noma i-norepinephrine,iyithululele ngaphakathi kweengazi. Abentwana abancani nabantu abadala babonisa ipendulo efanako kukambiso yokungenelelwa.

Kuhlelo lokuphefumula, isitho esibizwa nge-bronchial tree sesicishe siphelele.

Into emhlophe evikelako, ebizwa nge-vernix caseosa, seyivale i-fetus. I-Vernix ivikela isikhumba ukuthi singahlushwa zinkathazo ze-amniotic fluid.

Ukusukela eemvekeni ezi-19 ukusikinyeka kwe-fetus,ukuphefumula kwayo, nokubetha kwehliziyo kuthoma ukulandela ihlelo elithileko elibizwa nge-circadian rhythms.

Chapter 42   5 to 6 Months (20 to 24 Weeks): Responds to Sound; Hair and Skin; Age of Viability

EEMVEKENI EZI-20 indlebe yangaphakathi (cochlea), okusisitho sokuzwa, seyikhule njengeyomuntu omdala ngaphakathi kwendlebe ekhulileko ngaphakathi. Kusukela nje ukuya phambalil, i-fetus izakuphendula imidumo eminengi ngokuya kwesikhathi.

Izinwele zicala ukukhula ekhanda.

Koke ukwakheka kwesikhumba kukhona, kufake hlangana imbotshana yezinwele,nama-glands.

Eemvekeni ezi-21 ukuya kwe-22 Ngemva kokumumatha, amaphaphu athola ithuba lokuphefumula umoya. Lokhu kwaziwa ngokwazi ukuphila(viability) ngoba ukuphila ngaphandle kwesibeletho kuyazakala kwamanye ama-fetuses. Ukuphumelela okunengi Kwemithi elaphako kwenza kwenzakale ukuqhubela phambili impilo kulabo abazalwe ngaphambili kwesikhathi.

Chapter 43   6 to 7 Months (24 to 28 Weeks): Blink-Startle; Pupils Respond to Light; Smell and Taste

EEMVEKENI EZI-24 Isivalo selihlo siyavuleka futhi begodu i-fetus ibonisa ukuphendula ngokuphazamisa ilihlo. Lokhu kuphendula kumidumo yamsinyana,ephezulu kwenzakala msinyana ku-fetus yesifazane.

Imibiko embalwa ibonisa ukuthi ukuvezwa kumdumo ophezulu kungathikameza kabi ipilo ye-fetus. Imiphumela yamsinyana ukubetha kwehliziyo msinyana okuqhubekela phambili, ukugwinya kwe-fetus okungaphezulu, nokuziphatha okushintshako. Okungenzeka esikhathini esizako kufaka hlangana ukulahlekelwa kukuzwa.

Izinga lokuphefumula lingaphakama libe kufikela ama-44 ukukhipha nokufaka umoya ngeminithi.

Ngesikhathi senyanga yesithathu yokukhulelwa, ukukhula kwengqondo kudla amandla angaphezulu kwe-50% asetjenziswa yi-fetus. Ubudisi bengqondo bukhula phakathi Kuka 400 no 500%.

Kuveke yama-26 amehlo athoma ukuveza iinyembezi.

Amehlo athoma ukungafuni ukuthintana Nomkhanyo kusukela kumveke ezi-27. Ukungafuni ukuthintana nelanga Kuthikameza inani lomkhanyo kufikele kundawo yelihlo ethatha umfanekiso ubuphilo boke.

Zoke iindawo ekufunakala zisebenze ngokufukelela ziyasebenza. Izifundo ngabentwana ababelethwa kungakafiki isikhathi babonisa ikghono lokunukelela kusese ziimveke ezi-26 ngemva kokumumatha.

Ukufaka into enoshukela ngaphakathi kwe-amniotic fluid kungezelela ukugwinya kwe-fetus. Ngakwelinye ihlangothi, ukugwinya Kwe-fetus okwehlileko kulandela ukuba khona kwento enganambitheki. Ukushintsha ubuso kuvamisile.

Ngokwenza okufana nokusikinya imilenze okufana nokukhamba, i-fetus iyaphenduphenduka.

I-fetus ibonakala ingakashwabani kakhulu njengoba amafutha amanye ayangezelela abuya ngaphasi kwesikhumba. Amafutha adlala indima ekulu ekubambeni umfuthumela womzimba nokonga amandla emva kokubeletha.

Chapter 44   7 to 8 Months (28 to 32 Weeks): Sound Discrimination, Behavioral States

Emva kweemveke ezi-28 i-fetus iyakwazi ukuhlukanisa phakathi kwemidumo ephezulu nephasi.

Emva kweemveke ezi-30, ukusikinyeka kokuphefumula kuvamile begodu kwenzeka kusukela ku-30 ukuya ku-40% wesikhathi kwenye nenye i-fetus.

Ngesikhathi seenyanga ezi-4 zokugcina kokukhulelwa, i-fetus ibonisa iinkhathi zokwenzeka okuhlangeneko kuhlangene neenkhathi zokuphumula. Lezi iinkhathi zokuziphatha zibonisa ukukhula kokuhlangana kwendawo ephakathi yemizwa.

Chapter 45   8 to 9 Months (32 to 36 Weeks): Alveoli Formation, Firm Grasp, Taste Preferences

Qishe nakuzimveke ezi-32, i-alveoli yeqiniso, namkha amaseli wesikhwama (air "pocket" cells), athoma ukuvela emaphaphini. Azokuqhubeka akhule ukufikela eminyakeni eyi-8 ngemva kokubelethwa.

Eemvekeni ezi-35 i-fetus iyakwazi ukubamba ngesandla iqinise.

Ukuvezeka kwe-fetus kuzinto ezihlukile kubanakala kuthinta ukukhetha ukunambitha ngemva kokubelethwa. Isibonelo, ama-fetus abomama bawo abadla i-anise, into enambithisa i-licorice, babonisa ukuthanda i-anise emva kokubelethwa. Abasanda kubelethwa abazange Bavezwa ku-anise abayithandi.

Chapter 46   9 Months to Birth (36 Weeks through Birth)

I-fetus ithoma umsebenzi ngokukhipha amahomoni amanengi abizwa nge-estrogen begodu ithoma ukubeletha ukusuka ku-fetus ukuya emntwaneni osanda kubelethwa.

Ukubeletha kubonakala ngokuvuleka Kwesizalo, kugcine ngokubelethwa komntwana.

Ukusuka ekumumatheni ukufikela ekubelethweni nangaphambili, ukukhula komuntu kuhlangahlangene, kuyaqhubeka. Okusanda kuvela ngalekambiso ngokuya kubonisa ukuqakatheka kokukhula kwe-fetus ipilo yoke.

Njengo ukuzwisisa kwethu ukukhula komuntu kuya phambili, njalo nekghono lethu lokuragela phambili ngezepilo - ngaphambili ngangemva kokubelethwa.


Add a Comment

Your Name: Log In 3rd-party login: Facebook     Google     Yahoo

Comment: