HUMAN REPRODUCTIVE SYSTEM..

In this post we will discuss following points :

1. Male reproductive system

2. Female reproductive system

3. Structure of human gametes and role of hormones in male reproductive physiology 

4. Menstrual cycle in females 

5. Events in fertilisation in humans 

6. Gestation and endocrinology off  female reproductive system

7. Parturition and lactation 

Introduction 

Humans are sexually dimorphic means male and females individuals are separate . Male individuals possess testes as gonads whereas females have ovaries as gonads . Male and female also look different morphologically owing to secondary sexual characteristics . Male individuals produce sperms in testes whereas females produce ova in ovaries . Sperms are passed into female reproductive tract which may lead to fertilisation and formation of zygote a single cell which later undergoes mitotic divisions to produce multicellular structure called embryo. An embryo is an immature baby which get nutrition and protection inside mother womb and finally delivered out on maturity .Then mother feed the Baby with milk and takes care of him / her till it becomes self dependent for basic activities .

Male reproductive system

Male reproductive system has gonads , their glands and external genitalia .

Gonads are named testes in human male and they are enclosed in pouch like scrotal sac or scrotum . This scrotal sac has two chamber for testes . Scrotal sac provide lower-than body temperature for formation of sperms inside testes . Testes descend into scrotum from abdominal cavity via inguinal canal with the help of spermatic cords which is having blood vessels, nerves , muscles ( cremaster to raise or lower testes in response to low and high temperature ) . Connective tissue attaching base of testes to scrotal sac wall is called gubernaculum . Sometimes testes fail to descend this is called cryptorchidism . This results in sterility in male .

Testis themselves are enclosed in covering of outermost  tunica vaginalis , middle tunica albuginea and innermost tunica vasculosa .So tunica vasculosa is more near to seminiferous tubules which form sperms . Testes has about 250 lobules formed due to septa or partition of testicular space . Each lobule has 1-3 seminiferous tubules which are coiled tube like structure lined by germinal epithelial cells . These cells are also called sperm mother cells and become interrupted at places by Sertoli cells.Sertoli cells provide nutrition to developing sperms .These cells help to concentrate androgen by producing ABP ( androgen binding proteins ) in seminiferous tubules . Sperm mother cells undergo meiotic division and produce spermatids which get differentiated to form sperm cells .Between seminiferous tubules lies interstitial tissue which contain blood vessel , nerves and Leydig cells which produce androgen or testosterone hormone .These endocrine cells play important role in spermatogenesis .If we cut T.S. of seminiferous tubules we get empty space in centre which is generally named lumen . From lumen to border of these tubules we get layer of different cells . At the base lies spermatogonia which form layer of primary spermatocyte towards lumen . Primary spermatocytes undergo meiotic division and form secondary spermatocyte which in turn produce spermatids cells . Spermatids stop division process and just get modified into sperm. Sperms become attached to tip of Sertoli cells for nutrition . Blood is naturally prevented from coming in contact with sperms ( blood testis barrier ) .

CH 3 - HUMAN  REPRODUCTION

1.Each   testis       has  about  250   compartments  called----------------------

Ans-testicular lobules

2.The seminiferous  tubule is lined  by   two  types  of  cells  called---------------and  -----------------

Ans-male germ cells and Sertoli cells

3.-------------------cells  in  the  seminiferous  tubule   synthesise and   secrete  testicular hormone

Ans-interstitial cells  or leydig cells

4.The  cells  that  nourish  the sperm  in  the  seminiferous  tubule  is  called---------------

Ans-sertoli cells

5.----------------------cells  undergo  meiotic  divisions  and    produce sperms in testes

Ans-male germ  cells

6.The  secretions  of male  accessory  glands  collectively  called------------------------

Ans-seminal plasma

7.The   part  closer to the  ovary  is  funnel  shaped named---------------------------------------

Ans- infundibulam

8.The   wall  of  uterus  is  three  layerd  called--------------------,------------------,and------------------

Ans-perimetrium,myometrium,endometrium

9.-------------------------is  the   tiny  finger like  structure  that  lies at the  upper  junction  of  the

 Two   labia  minora  above   the  urethral  opening

Ans-clitoris

10.Fertilisation  in  huaman  occurs  at ----------------------of the   oviduct

Ans-ampulla  isthmus junction

11. A  primary spermatocyte   completes  the  first  meiotic  division  leading to  the formation of    two  equal    haploid  cells called------------------------------------------

Ans-secondary spermatocytes

12.-----------------------pitutary  hormone    acts  on  the  Leydig cells   and  stimulate  synthesisis

And  secretion  of  androgens

Ans-LH

13.The  sperm    head  contain  an  elongated   haploid nucleus ,the   anterior portion  of  which

Is  covered  by  a  cap like  structure  called-------------------------

ANS-acrosome

14.The   seminal  plasma    along  with the  sperms  constitute-----------------------

Ans-semen

15.The    primary  follicle    get  surrounded  by  more  layers of  granulose cells   and  new  theca

       And   are  called----------------------------------

Ans-secondary follicles

16.The  tertiary  follicle  is  characterized  by  a  fluid  filled cavity called------------------------

Ans-antrum

17.The  secondary  oocyte    forms  a  new  membrane  at  the  time  of  ovulation  ------------------

Ans-------zona pellucida

18.The  first  menstruation  begins  at puberty  is called--------------------------------

Ans-menarch

19.After  the  ovulation  the   ruptured     graffian  follicle  changed into  yellow mass  of

Cells  that produce  progesterone  called-----------------------------------------

Ans-corpusluteum-

20.On  the  14 th   day  of  menstrual cycle   the  pituitary  hormones----------------and-----------are

Peak  in  the  blood

Ans-LH  and FSH

21.The  hormone(pituitary)  that  help in  the  ovulation  is------------------------------

Ans  LH

22.The  embryo  with  8  to  16 blastomers  called-------------------------------------

Ans-morula

23.The blastomeres  in  the  blastocyst    are  arranged  into  an  outer layer  called  -----------------

And  an    inner  group  of  cells  attached   to  it  is called-----------------------

Ans-trophoblast  and inner  cell  mass

24.The  chorionic villai   and uterine tissue   become   interdigitated  with   each other   and  jointly   form    a  structural  and  functional  unit between foetus and  maternal  body called

---------------------------------

Ans-placenta

25.The  placenta   produces  two  hormones---------------------and -----------------------------

Ans-human chorionic  gonadotrophin,placental lactogen

26.The  inner cell  mass  contains    certain  cells  called-----------------cells   which  have the

Potency  to    give  rise  to all  the  tissues  and  organs

Ans-stem  cells

27.The  signal  for  parturition  arise from  -------------------and ------------------------

Ans-fully  matured foetus  and  placenta

28.The  milk  produced    during the  initial  days of  lactation is  ---------------------which  contains

Several  antibodies  essential  for  the  child

Ans-colostrum

29.Why   it  is   seen  that  the  testis  located  out  side  the  body  wall?

Ans-The  testes  are  located  out side  the  abdominal  cavity  within  a  pouch called  scrotum

Which  helphs in  maintaining  the  low  temperature  of  testes 2 to 2.5^oc  lower than that

        Of the   body  that   is  very  essential for  spermatogenisis

30.Name  the  human  male  accessory  glands

Ans-seminal vesicles,prostrate  gland, bulbourethral  glands

31.Mention  the  role  of  fimbriae  in  fertilization.

Ans-The  edges  of   infundibulum  possess  finger like  projections   called  fimbriae which helph in  collection  of  ova  during  ovulation

32.Mention  the  role  of  endometrium  in  fertilization

Ans-The  endometrium   undergoes  cyclical  changes   during  menstrual  cycle ,this  is  highly

Glandular  in  nature  and    implantation  of  embryo occur  on  it.

33.What is  the  composition of  seminal plasma

Ans-fructose,calcium  and certain  enzymes