(i) Formation of skin, sweat glands, oil glands, mammary glands etc.
(ii) Creation of hair, nails, feathers, horns, scales and scales.
(iii) Structure of retina, cornea and lens of the eye.
(iv) Covering structure of lips, lips, oral glands and tongue.
(v) Membranous labyrinth of inner ear and enamel structure of teeth.
(vi) Covering formation of pituitary gland and pineal gland.
(vii) Forms part of kidney medulla, integument of anus and cloaca.
(viii) Nervous system and sensory organs.
Consequences of embryo and embryonic layer
The zygote divides repeatedly to form a multicellular structure called an embryo. A human embryo has three layers. The consequences of embryonic stage three are-
1. Consequences of ectoderm
(i) Formation of skin, sweat glands, oil glands, mammary glands etc.
(ii) Creation of hair, nails, feathers, horns, scales and scales.
(iii) Structure of retina, cornea and lens of the eye.
(iv) Covering structure of lips, lips, oral glands and tongue.
(v) Membranous labyrinth of inner ear and enamel structure of teeth.
(vi) Covering formation of pituitary gland and pineal gland.
(vii) Forms part of kidney medulla, integument of anus and cloaca.
(viii) Nervous system and sensory organs.
2. Consequences of mesoderm
(i) Formation of the dermis of the skin.
(ii) Formation of dentin of teeth and various parts of eye.
(iii) Formation of notochord, spinal cord, skeletal system, connective tissue and muscular tissue.
(iv) Formation of blood cells, lymph and lymph glands, excretory system, reproductive system and circulatory system.
(v) Structure of stomach and intestinal musculature and renal cortex.
(vi) Heart, the inner wall of the body cavity.
3. Consequences of endoderm
(i) Structure of pharynx, esophagus, stomach and intestines.
(ii) Formation of lining of digestive tract.
(iii) Formation of kidney, liver and pancreas.
(iv) Formation of middle ear and tonsils.
(v) Formation of thymus, thyroid and parathyroid.
(vi) Covering of the excretory canal, urethra and urinary bladder.
(vii) Formation of respiratory system and reproductive system.
Immortal work (Placenta)
1. Implantation: Placenta attaches the embryo to the uterus.
2. Nutrient supply: It supplies nutrients to the fetus from the mother’s body.
3. Storage: Placenta stores glycogen, fat and iron.
4. Gaseous exchange: It involves the exchange of O2 and CO2 between the maternal body and the fetus.
5. Hormone secretion: It secretes estrogen, progesterone, lactogen, gonadotrophin hormones.
6. Medicines: Medicines reach the fetus from the mother’s body through the mother’s mother.
7. Germ-carrying: Germs enter the embryo through the embryo and cause fatal damage.
8. Immunity: Antibodies from the mother’s body enter the fetus and prevent disease.
9. Protects the fetus: Placenta protects the fetus from high blood pressure of the mother.
10. Excretion: Excretion is released through the Placenta.
Placenta definition
The organ through which the fetus receives nutrients from the mother’s body and removes waste from the body is called placenta. The placenta is formed 12 weeks or 3 months after fertilization. Its weight is 600 grams, thickness is 4 cm and color is reddish-brown. It is attached to the fetus by the umbilical cord.
Ninth month of Fetus
Lungs are fully developed. The baby’s eyes blink, head nods and fingers clench. Responds to light, sound and touch. At that time the child was 50.80 cm long and weighed 7 pounds.
Eighth month of Fetus
Baby grows rapidly and can see and hear. All organs are developed except the lungs. At that time the child was 45.70 cm tall and weighed 5 pounds.
Seventh month of Fetus
Fat accumulates in the body. The hearing organ is fully developed. Responds to sound, pain and light. At this time, the baby is 35.55 cm long and weighs 4 pounds.
Sixth month of Fetus
The skin is red and wrinkled. Veins are visible on the skin. Fingerprints are visible. Eyelids begin to open. By the end of the sixth month, the baby is 30.48 cm long and weighs 2 pounds.
Fifth month of Fetus
Hair grows on the head. The skin is covered with lanugo (soft hair). By the end of the fifth month, the fetus is 25.4 cm long and weighs 0.5-1 lb.
Fourth month of Fetus
Eyelids, eyebrows, nails and hair develop. Arms and legs move. Can suck thumb. By the end of the fourth month, the fetus is 13 cm long and weighs 141 (5 oz) grams.