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प्रश्न
The diagram given below is that of a developing human foetus. Study the diagram and then answer the questions that follow:
(i) Label the parts numbered 1 to 3 in the diagram.
(ii) Mention any two functions of the part labelled 2 in the diagram.
(iii) Explain the significance of the part numbered 3 in the diagram.
(iv) Define the term ‘Gestation’. What is the normal gestational period of the developing human embryo?
(v) Mention the sex chromosomes in a male and female embryo.
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उत्तर
(i)
- Umbilical cord
- Placenta
- Amniotic fluid
(ii) Functions of placenta:
- It allows the diffusion of oxygen, nutrients and immune products from the mother to the foetus.
- It allows the diffusion of waste material generated by the foetus to the mother to be excreted.
(iii)
- The amniotic fluid prevents the foetus from injury and shocks.
- It allows the foetus some amount of movement.
- It prevents the amnion from sticking to the foetus.
- It maintains an even pressure all around the foetus.
(iv) The time period required for the development of the foetus inside the uterus is called gestation. The normal gestation period in humans is 280 days (9 months).
(v) Male sex chromosomes: One ‘X’ chromosome and one ‘Y’ chromosome (XY) Female sex chromosomes: Two ‘X’ chromosomes (XX)
APPEARS IN
संबंधित प्रश्न
Describe, in brief, the changes the uterus undergoes
(i) to receive the zygote.
(ii) if zygote is not formed
List the two types of reproduction. Which one of the two is responsible for bringing in more variations in its progeny and how?
Match the Column:
| no | Column A | Column B |
| 1 | Allele | Control of automobile exhaust |
| 2 | Leydig cells | Tourniquet |
| 3 | Utriculus | Alternate forms of genes |
| 4 | Snake bite | Dynamic equilibrium |
| 5 | Euro IV norms | Testosterone |
| Sudden change in genes | ||
| Static equilibrium |
For how much time does menstruation last in human females (or women)?
The normal body cell of an organism contains 28 pairs of chromosomes. The number of chromosomes present in its germ cell will be
(a) 28
(b) 14
(c) 56
(d) 42
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.
Rewrite the terms in the correct order so as to be in a logical sequence.
Implantation, ovulation, child birth, gestation, fertilisation.
Describe in brief the role of seminal vesicle in human male reproductive system.
Choose the Odd One Out:
The membranous cover of the ovum at ovulation is ______.
