Biology [3 marks Question Answer]

(i) (1) Sperm Duct (Vas deferens)
(2) Seminiferous Tubule
(3) Lobes of Testis (lobule)
(4) Epididymis
(ii) The function of Sperm Duct (1): It carries sperms from testis to urethra.
(iii) The function of Seminiferous tubule (2) : Sperms are produced here. The process is called spermatogenesis.

(i) Female reproductive system:



(ii) Functions of:
(a) Placenta:
• It provides nutrition to foetus.
• It provides oxygen and removes carbon dioxide from the foetus to the mother's blood through diffusion.
• It prevents the entry of germs into the foetus and gives protection from infection.
• It secretes hormones.
(b) Amniotic fluid:
• It acts as a cushion for the embryo and protects it from jerks or mechanical shocks.
• It prevents sticking of the foetus to the amnion.

(i) 1. Umbilical Cord
2. Placenta
3. Amniotic fluid
4. Cervix/Mouth of Uterus
5. Uterine wall
(ii) Gestation Period
(iii) The part labelled as 2 provides nutrition and exchange of respiratory gases by diffusion.

(i) Artificial insemination: When sperms of mature male are transferred to the female body by means other than the natural process. The procedure is called artificial insemination.
This method is usually adopted to improve cattle breed. It involves collection of sperms of good quality bull, proper storage of sperms and their transfer into the vagina of a cow having desirable qualities.
(ii) Test-tube babies : In some women, normal conception is not possible. In such cases, ovum from the female and sperm from the male is collected and fertilisation is carried out in a test tube under controlled conditions. When the zygote reaches the 32 -cell stage, it is implanted inside the uterus of the mother, where the foetus grows to full term.

(i)1 - Umbilical artery
2 - Umbilical vein
3 - Uterine artery
4 - Uterine vein
5 - Maternal portion of placenta
6 - Foetal portion of placenta
(ii) Substances diffusing across placenta:

Into the placenta	Out of the placenta
Oxygen Glucose, amino acids, salts and   minerals.   Hormones	Carbon dioxide   Nitrogenous metabolic wastes

(iii) Functions of placenta:
• Transfers oxygen, water, nutrients and hormones from the mother to the foetus.
• Transfers wastes from the foetus to the mother's blood.
• Provides protection to the foetus as it does not allow microorganisms in mother's blood to pass through it to the foetus.
• Produces hormones such as oestrogen, progesterone and relaxin which are necessary to maintain pregnancy.
• It supplies nutrition, oxygen and other requirements to the foetus. It acts as an endocrine organ as it secretes oestrogen and progesterone during the last six months of pregnancy.

(A - d), (B - a), (C - c), (D - b)

CORPUS CALLOSUM	CORPUS LUTEUM
It connects the two cerebral hemispheres (of brain)  internally.	Corpus luteum produces the hormone,   progesterone  (female sex hormone).
It enables the communication between two   hemispheres.	It prepares the inner lining of the uterus for  implantation of zygote.

 

 

IMPLANTATION	GESTATION
Implantation is the attachment of the blastocyst to the uterine wall.	It is time period of developmental events from conception till birth of the young one.