Advertisements
Advertisements
Question
How many eggs are released by a human ovary in a month? How many eggs do you think would have been released if the mother gave birth to identical twins? Would your answer change if the twins born were fraternal?
Advertisements
Solution
Each ovary produces several immature eggs, which are connected with groups of other cells known as follicles. In humans, only one egg is usually removed at a time; however, two or more may emerge during the menstrual cycle. The egg emerges from the ovary between the 14th and 16th days of the typically 28-day menstrual cycle. Fertilisation of a single egg results in one zygote (monozygotic) that divides into two embryos, forming identical twins. If the twins were born fraternal, two eggs would be released. Fraternal twins (also known as non-identical twins) are typically formed when two fertilised eggs are implanted in the uterine wall at the same time. The two eggs produce two zygotes; hence, these twins are also known as dizygotic or binovular twins.
APPEARS IN
RELATED QUESTIONS
Given here is a section of the female reproductive system of human beings.
Name the parts labelled 1 to 4
Differentiate between:
Prostate gland and cowper’s gland (the nature of secretion)
Explain the concept of IVF.
Mention the exact location of the following :
Corpus callosum
Give appropriate term of the following:
The rupture of follicle and release of ovum from the ovary.
Give appropriate term of the following:
The process of fusion of ovum and sperm.
Name the following:
The parts of the ovary containing mature ovum.
Why is zona pellucid retained around the egg till it reaches the uterus?
Draw a sectional view of the human ovary. Label the following parts :
(ii) Secondary oocyte
(iii) Graafian follicle
(iv) Corpus luteum
The below diagram represents the vertical view of the human female reproductive system.
(i) Label the parts indicated by the guidelines 1 to 8.
(ii) How does the uterus prepare for the reception of a zygote?
(iii) What happens to the uterus if fertilization takes place?
(iv) What happens to the uterus if fertilization has failed to take place?
Name the part of the human female reproductive system where the following occurs.
Implantation
What is the other term used for fallopian tube?
Penis is homologous to ____________.
Identify the layer of the uterine wall that undergoes changes during menstrual cycle.
Which stage is followed after the secondary follicle stage?
Which of the following is ectodermal in origin?
| (i) | Heart |
| (ii) | Sweat glands |
| (iii) | Adrenal medulla |
| (iv) | Middle ear |
| (v) | Urinary bladder |
| (vi) | Dermis of skin |
Which of the following is a finger like structure and lies at the upper junction of the two labia minora above the urethral opening?
The second maturation division of the mammalian ovum occurs ______.
The opening of the vagina is often covered partially by a membrane called ______.
Read the following and answer from given below:
During copulation, semen is released by the penis into the vegina. The motile sperms swim rapidly, fuse with the ovum in the ampullary region, resulting in fertilization. The haploid nucleus of sperm fuses with that of the ovum to form a diploid zygote.
Select the correct sequence of various physical and chemical events that take place during fertilisation.
P. Fusion of cortical granules with the plasma membrane of secondary oocyte.
Q. Formation of fertilization cone to receive sperm.
R. Release of sperm lysin from acrosome.
S. Mixing up of chromosomes of a sperm and an ovum.
How does fertilisation take place? Fertilisation occurs once in a month. Comment.
In rabbits, humans and other placental mammals, fertilization occurs in ______.
What is parturition?
With a suitable diagram, describe the organisation of mammary gland.
Given below are the structural details of a human mammary gland:
- The glandular tissue in the breast has 15-20 clusters. of cells called alveoli.
- The milk is stored in the lumen of the alveoli.
- The alveoli join to form the mammary ducts.
- Mammary ampulla is connected to lactiferous ducts.
Choose the option that gives the correct detail of the human mammary gland.
In absence of fertilization, corpus luteum degenerates into ______.
The ______ is also called the womb.
Rewrite the terms in the correct order so as to be in a logical sequence.
Graafian follicle, ostium, uterus, fallopian tube, ovum.
Given below is a group of terms. In the group, one pair indicates the relationship between the two terms. Rewrite and complete the second pair on a similar basis.
Leydig cells : Testosterone : ______ : Oestrogen.
