Give reasons :
(i) Placenta is extremely essential for foetal development.
(ii) Uterine lining becomes thick and spongy after fertilisation.
Give reasons :
(i) Placenta is extremely essential for foetal development.
(ii) Uterine lining becomes thick and spongy after fertilisation.
(i) Importance of Placenta:
The placenta is a specialized disc-like tissue embedded in the uterine wall of the mother. It is extremely essential for foetal development because:
- Nutrient and Oxygen Supply: It provides a large surface area (via villi) for glucose, oxygen, and other essential nutrients to pass from the mother's blood to the developing embryo/foetus.
- Waste Removal: It allows the metabolic waste substances generated by the developing embryo to be transferred into the mother's blood for excretion.
(ii) Thickening of Uterine Lining:
After fertilisation, the zygote begins to divide and forms an embryo which implants itself in the lining of the uterus. The uterine lining becomes thick, spongy, and richly supplied with blood vessels to:
- Nourish the Embryo: Provide a continuous supply of oxygen and nutrients to the growing embryo.
- Support and Protect: Ensure safe implantation, cushioning, and further development of the foetus throughout the gestation period.
Marking Scheme
- 1For stating that the placenta provides nutrients/oxygen and removes waste: 1 Mark
- 2For explaining that the thick and spongy uterine lining is richly supplied with blood to nourish and support the implanted embryo: 1 Mark
Hint
Think about how the developing embryo gets its food and oxygen from the mother, and how the uterus prepares itself to receive and nourish the zygote.
Quick Oral Answer
The placenta is a disc-like tissue embedded in the uterine wall that facilitates the exchange of nutrients, oxygen, and waste products between the mother and the foetus.
Analysis & Explanation
The placenta acts as a physiological barrier and exchange medium between the maternal and foetal circulatory systems. On the embryonic side, it contains finger-like projections called villi, which are surrounded by blood spaces on the maternal side. This design maximizes the surface area for efficient diffusion. The thickening of the uterine lining is a hormonal response. Every month, the uterus prepares itself to receive a fertilised egg. If fertilisation occurs, this thick, vascularized lining is maintained to support pregnancy; if fertilisation fails, the lining breaks down and is shed during menstruation.
Common Mistakes
- 1Students often forget to mention the removal of waste products when explaining the role of the placenta.
- 2Some students confuse the state of the uterus before and after fertilisation, not realizing that the lining thickens in anticipation of implantation every month, but remains thick and spongy after fertilisation to support the embryo.
Interesting Facts
The placenta is the only temporary organ in the human body; it is created specifically for pregnancy and is expelled from the mother's body shortly after the baby is born!
Spotted a mistake or something unclear?
Tell us — we fix reported answers fast.
Frequently Asked Questions
How many marks does this question carry in CBSE Class 10 Science 2022?
This question carries 2 marks in the CBSE Class 10 Science 2022 examination.
Which chapter does this question come from in Science?
This question is from the chapter "How do Organisms Reproduce?" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "Sexual Reproduction in Human Beings" from CBSE Class 10 Science.
What type of question is this in the CBSE Class 10 Science 2022 paper?
This is a Short Answer question from Section Section A in the CBSE Class 10 Science 2022 paper.