This set of Class 12 Biology Chapter 3 Multiple Choice Questions & Answers (MCQs) focuses on “Human Reproduction – Menstrual Cycle – 1”.
1. Primate female reproductive cycle is called ________
a) menstrual cycle
b) water cycle
c) blood cycle
d) ovarian cycle
Explanation: Mammals exhibit an estrous cycle wherein if the egg is left unfertilized the endometrium is resorbed. In primates like humans, however, the endometrium is shed. This cycle unique to very few mammalian species is called as the menstrual cycle.
2. The first menstrual flow is called as ___________
Explanation: The first menstruation occurs during puberty in humans. This menstrual is called menarche, which means the onset of menstruation and hence the ability to get fertilized.
3. The menstrual cycle in humans lasts for a lunar month.
Explanation: Menstruation occurs in all primates. It varies across species lasting from days to months. In humans, it lasts approximately for a lunar month i.e., 28-29 days.
4. Ovulation occurs at the onset of the menstrual cycle.
Explanation: The menstrual cycle is timed from the day of bleed to the day before the next bleed. Ovulation or release of egg happens on 14th to 15th day of the menstrual cycle.
5. The onset of the menstrual cycle is characterized by a discharge of blood and tissue matter from the uterus. What is this discharge termed as?
Explanation: Menses is the shedding of the endometrial lining along with the unfertilized egg. Thus it is composed of blood and tissue discharge. It lasts for 3-5 days.
6. What layer of the uterus is shredded during menstruation?
Explanation: Uterus is composed of three layers of tissues. The outer perimetrium holds uterus in shape. The middle myometrium is responsible for contractions while the innermost endometrium is the layer that holds the egg. During menstruation, the inner layer is shredded off along with the egg and the supplying blood vessels.
7. Which of the following can lead to a menstrual cycle?
a) Fertilization of egg
b) Unfertilized egg
c) Improper sleep
d) Study pressure
Explanation: The menstrual cycle is a natural phenomenon. It arises as the unfertilized egg needs to be released along with the thick endometrium that was formed in anticipation of the would-be embryo.
8. Which of the following will not result in a miss in the menstrual cycle?
a) Fertilization of the egg
b) Anxiety and stress
c) Bad health
Explanation: Menstrual cycle occurs as a result of the need to remove the unfertilized egg. Thus if egg is fertilized, the menstrual cycle is skipped. However, other factors like bad health, anxiety, and stress, etc. can also lead to improper body rhythm and thus a miss in the menstrual cycle. Gyming and exercise are healthy habits and keeps your body in check. Thus won’t affect your body rhythm.
9. The phase during which menses occur is called _______
a) primary phase
b) follicular phase
c) menstrual phase
d) luteal phase
Explanation: The menstrual cycle begins with release of blood and mucus. This discharge is called menses. This phase of the menstrual cycle is hence called the menstrual phase.
10. The follicular phase is also called as __________
a) menstrual phase
b) luteal phase
c) proliferative phase
d) secretory phase
Explanation: The follicular phase follows the menstrual phase. It is characterized by the maturation of primary follicles to Graafian follicles. Since there is a lot of growth around the developing egg cell, it is called the proliferative phase.
11. During what phase of menstrual cycle are primary follicles converted to Graafian follicles?
a) Menstrual phase
b) Follicular phase
c) Luteal phase
d) Secretory phase
Explanation: Primary follicles mature with the addition of theca, granulosa cells, and antrum to form a mature Graafian follicle. All of these changes along with the completion of the first round of meiosis occurs during the follicular phase also otherwise called as the proliferative phase.
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