Q19 of 27 Page 1

(a) Write the function of following parts in human female reproductive system :

(i) Ovary (ii) Oviduct (iii) Uterus


(b) Describe in brief the structure and function of placenta.



(a) (i) Ovary: A pair of ovaries is present in the human female reproductive system. Ovaries produces ova (eggs/female gametes) Ovaries are also responsible for producing estrogen, which is a female hormone involved in the development of secondary sexual characters.


(ii) Oviduct: It is responsible for carrying the mature ovum to the uterus. The oviduct is also the place where fertilization takes place.


(iii) Uterus: Uterus or the womb is the place where the fertilised egg gets implanted and it nurtured. It holds and supports the developing foetus.


(b)Placenta is an organ that develops in the uterus during pregnancy. It is like a disc which is embedded in the uterine wall. On the foetal side of tissue, villi are present and on the maternal side there are blood spaces. The umbilical cord arises from the placenta.


Function: The placenta provides nutrition to the developing foetus from the mother. It is a connection between the mother and the foetus. The waste generated by the foetus is also removed by transferring them into the mother’s blood through the placenta.


More from this chapter

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17

(a) The modern periodic table has been evolved through the early attempts of Dobereiner, Newland and Mendeleev. List one advantage and one limitation of all the three attempts.

(b) Name the scientist who first of all showed that atomic number of an element is a more fundamental property than its atomic mass.


(c) State Modern periodic law.


 18

(a) Mention any two components of blood.

(b) Trace the movement of oxygenated blood in the body.


(c) Write the function of valves present in between atria and ventricles.


(d) Write one structural difference between the composition of artery and veins.


OR


(a) Define excretion.


(b) Name the basic filtration unit present in the kidney.


(c) and label the following organs of


excretory system which perform following functions :


(i) form urine.


(ii) is a long tube which collects urine from kidney.


(iii) store urine until it is passed out.


 20

(a) A student is unable to see clearly the words written on the black board placed at a distance of approximately 3 m from him. Name the defect of vision the boy is suffering from. State the possible causes of this defect and explain the method of correcting it.

(b) Why do stars twinkle? Explain.


OR


(a) Write the function of each of the following parts of human eye:


(i) Cornea (ii) Iris (iii) Crystalline lens (iv) Ciliary muscles


(b) Why does the sun appear reddish early in the morning? Will this phenomenon be observed by an astronaut on the Moon? Give reason to justify your answer.


 21

(a) State Fleming’s left hand rule.

(b) Write the principle of working of an electric motor.


(c) Explain the function of the following parts of an electric motor.


(i) Armature (ii) Brushes (iii) Split ring