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प्रश्न
Describe placenta structure.
उत्तर
The placenta is a temporary organ that forms in your uterus during pregnancy. It attaches to your uterine wall and provides nutrients and oxygen to your baby through the umbilical cord. Certain conditions of the placenta can cause pregnancy complications.
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संबंधित प्रश्न
Explain the process of fertilization in human beings.
fill in the blanks with suitable functions: Seminiferous Tubule and _____
What do the ovaries in a woman produce?
Which among the following are not the functions of testes at puberty?
(i) formation of germ cells
(ii) secretion of testosterone
(iii) development of the placenta
(iv) secretion of estrogen
When a fertilised egg E formed in the oviduct of a human female divides repeatedly to form an embryo, the embryo gets implanted in the thick and soft lining of the uterus. After this a disc-like special tissue T develops between the uterus wall and embryo through which all the requirements of the developing embryo (and foetus) are met from the mother's body, The embryo is connected to the tissue T through a string like structure S.
(a) What is the other name of fertilised egg cell E?
(b) What is the name of tissue T?
(c) Name the string-like structure S.
(d) Name two substances which pass from mother's blood to embryo through tissue T and, one type of substance which passes from embryo to mother's blood.
(e) What happens to S when the baby is born? Why?
When a female child is born, her ovaries already contain thousands of immature eggs (or ova) contained in immature structures A. On maturing, A bursts open and an egg shoots out of the ovary in a process called B. The process B starts in the females at puberty and occurs again and again after a time period x. Before every occurrence of process B, the inner lining of uterus becomes thick and soft with lots of blood vessels in it. When the egg cell gets fertilised by a sperm, then an event C occurs in the life of mature human female which lasts for time period y leading to the birth of baby. If, however, the egg cell released by the ovary does not get a sperm to fuse with, then the thick and soft inner lining of uterus breaks down and comes out of the female's body in an event called D. The occurrence of event D is controlled by chemical substances E.
(a) What are A?
(b) What is process B?
(c) What is the time period x?
(d) Name the event C.
(e) How much is the time period y?
(f) What is the name of process D?
(g) Name the chemical substances E.
Define the following:
Clone
What are the signs of puberty in human males and females?
Freshly released human egg has ______.
Mention any two changes that are common to both boys and girls in early teenage years.
