a) Explain the role of placenta in the development of human embryo.
b) Give example of two viral sexually transmitted diseases. Name the most effective
contraceptive which prevents spread of such diseases.
Answers
Answer:
(a) Role of placenta in the development of human embryo: A special tissue develops between the uterine wall and the embryo foetus called placenta where exchange of nutrients glucose and oxygen takes place. The developing embryo will also generate waste substances which can be removed by transferring them into the mother’s blood through the placenta. The development of the child inside the mother’s blood takes approximately nine months. b Sexually transmitted diseases STDs transmitted by bacteria are: i Gonorrhoea ii Syphilis STDs transmitted by virus: i AIDS ii Genital warts The most effective contraceptive which prevents the spread of these diseases is by the use of mechanical barriers such as physical devices like condoms.
(b)Sexually trasmitted disease are those diseases that can be transmitted from infected person to healthy by sexual contact. It can be caused by virus and bacteria such as
Virus: AIDS and hepatitis B.
Bacteria: Gonorrhoea and syphilis.
Sexually transmitted diseases can be prevented by:
Avoid blood transfusion from an infected person.
Avoid multiple or unknown sexual partners.
Used needles and syringes should not be reused.
proper treatment should be given to the pregnant woman to prevent the child getting infected.
Answer:
1st answer The placenta plays a key role in the nutrition of the fetus. It mediates the active transport of nutrients and metabolic wastes across the barrier separating maternal and fetal compartments, as well as modifying the composition of some nutrients through its own metabolic activity.
Explanation:
2nd answer Gonorrhea, syphillis(bacteria)
HIV, genital herpes(virus)