What is Fertilization & Stages of Gestational Development
- Developmental process starts with fertilization and the zygote so formed as a result of fusion of ovum and sperm, which after a fixed duration forms an entire human, stores the coded genetic information.
- Stages of gestational development – the period of gestational development is 9 months which is divided into 3 stages-
Stages of Gestational Development
1. Zygote formation —
- This stage starts with the fusion of an ovum and sperm forming a zygote. It lasts for two weeks. The internal part of zygote undergoes constant cell division as a result the number of cells goes on increasing. After fertilization, for 7-8 days, the fertilized egg floats in the fluid present in mother’s uterus. After 10 days, the conceptus adheres to the wall of the uterus which is called implantation. From the first group of cells the body is developed, from the second group of cells umbilicus and placenta develops and the third cell group takes the form of transparent membranes. Inside these membranes the unborn baby develops and grows and stays protected.
2. Embryonic period —
- In this stage the process of development starts. This begins from the third week and continues until the end of the 10th week of gestation. The growing multicellular organism is called embryo. The structural development of the foetus is completed in this period.
- Outer membrane- This is the outermost membrane of the foetus from which hairs, nails, skin, teeth and vascular system of the baby are fabricated.
- Middle membrane- From this membrane the middle part of skin and muscles are fabricated.
- Inner membrane-All the vital organs (lungs, brain, liver, digestive system) are fabricated. With the end of embryonic period the foetus grows up to 1-1/4 inches to 2 inches and has a mass of 15-20 grams. The heartbeat of the baby starts and umbilical cord is developed till the end of this period.
3. Period of foetus-
- This stage is from 3% month until the baby is born. In this period various organs and muscles of the baby are fully developed and all the organs become functional. Height, size, shape, and weight grow rapidly.
- 3rd month- In this month the baby looks like a stumpy semicircle. The spinal cord begins to form. The body grows in height and by the end of month hands and feet begin to grow. Pink skin starts forming. The size of the head is 1/3″ that of body and kidneys begin to function. The face too starts developing. External ears, eyelashes are formed and hands continue growing. Height is about 6-8 cm and weight 34 ounces. Nutrition is supplied by umbilical cord. Uterus grows in size.
- 4″ month- Head grows bigger in size. Hair too begin to grow. Back of the foetus is arched and nails in hands and feet, teeth in gums begin to develop. Reproductive organs also develop in this month. By the end of this month internal organs begin their functions. Height is 11-12 cm and weight grows up to 100-110 grams.
- 5″ month- Heartbeat becomes distinct. Muscles become active thus becoming more functional. Height is 18-20 cm while weight becomes 280-300 grams.
- 6″ month- Soft hair begin to grow on skin and a white cream like sticky, oily fluid called vermix starts depositing on the skin. Mother begins feeling the baby’s movements. The eye lashes grow separately. Head grows rapidly. By the end of the month, the foetus grows up to 30-32 cm in height and weight is 600-750 grams.
- 7″ month- The baby is fully developed in this month. Nails in fingers are completely developed. The foetus takes up a single position and activity of the baby decreases. The height grows up to 15-16 inches and weight up to 1.5-2 kg.
- 8″ month- Eyes are fully developed, retina is fabricated, respiration begins and fat on skin and body starts accumulating. The baby attains full maturity.
- 9″ month- Colour of the skin becomes natural. Hair grow. Lips turn thin and pink. Fatty tissues grow quantitatively. By the end of 9* month weight becomes 3.0-3.5 kg and height up to 18-20 inches. Contractions begin at the end of this month. Before birth the baby slowly shifts towards lower part of the uterus.
Factors affecting gestational period
1. Nutrition of expecting mother
2. Health of the mother
3. Consumption of drugs and alcohol
4. Emotional feelings of mother
5. Age of mother-father
6. Attitude of mother-father
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Important Points of Pregnancy :-
- The gestational period is 9 months and 7 days. The gestational period is counted from the last day of menstrual cycle till the day of childbirth.
- A late period, morning sickness, urge for more sleep, frequent urination, enlargement of stomach etc are some of the symptoms of first 5 months of pregnancy.
- Growth in self-activity of foetus, increase in weight of breasts, contraction in muscles of legs and uterus etc are some of the symptoms of the last 5 months of pregnancy.
- Changes in metabolism, urinary tract, blood circulation, respiration, pelvic joints etc are some of the internal changes in pregnancy. Three stages of pregnancy- zygote formation, embryonic stage, and foetus.
- Nutrition, health of expecting mother, consumption of drugs and alcohol, emotional feelings of mother, age of mother-father affects the gestational development.
- Insomnia, hemorrhoids, inflammation, short breath, constipation, chest burn, vomiting etc are the hardships of pregnancy.
- For the good health of baby and herself mother should take a balanced diet.
Pregnancy Questions and Answers
1. The gestational period is
(a) 10 months 2 days
(b) 9 months 7 days
(c) 8 months
(d) 7 months
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2. The initial symptom of pregnancy is
(a) Urge to sleep more
(b) late period
(c) More saliva secretion
(d) frequent urination
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3. Mother gets the indication of foetus’ presence in
(a) 3″ month
(c) 4″ month
(b) 7″ month
(d) 6″ month
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4. The first stage of gestational development is
(a) Embryonic stage
(b) foetus
(c) Implantation
(d) zygote formation
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5. Implantation in pregnancy is
(a) Formation of gums in foetus
(b) adherence of foetus to uterine wall
(c) Placenta
(d) formation of organs and muscles
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6. In which month is gender decided
(a) 2″ month
(b) 4″ month
(c) 5″ month
(d) 6″ month
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7. Factors affecting gestational development
(a) Nutrition of mother
(b) attitude of mother father
(c) Consumption of drugs and alcohol
(d) all of these
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8. Weight of child at the time of birth should be
(a) 2.5-3.0 kg
(b) 3.0-3.5 kg
(c) 5.0-6.0 kg
(d) 4.0-4.5 kg
Answer :- ?????