Notes: Chapter - Human Reproduction, Class 12, Biology PDF Download

 Page 1


K C MEENA 
PGT BIOLOGY 
 KV VIKASPURI II SHIFT 
 
1 
 
HUMAN REPRODUCTION 
  
THE MALE REPRODUCTIVE SYSTEM. 
          
? Located in the pelvis region. 
? Male reproductive system includes 
o A pair of testes. 
o Accessory ducts. 
o Accessory glands. 
o External genitalia 
Testes: 
  
? Located outside the abdominal cavity within a pouch called scrotum. 
? Scrotum provides low temperature required for spermatogenesis. 
? Each testis is about 4 to 5 cm length and 2 to 3 cm width. 
? Each testis has about 250 compartments called testicular lobules. 
Page 2


K C MEENA 
PGT BIOLOGY 
 KV VIKASPURI II SHIFT 
 
1 
 
HUMAN REPRODUCTION 
  
THE MALE REPRODUCTIVE SYSTEM. 
          
? Located in the pelvis region. 
? Male reproductive system includes 
o A pair of testes. 
o Accessory ducts. 
o Accessory glands. 
o External genitalia 
Testes: 
  
? Located outside the abdominal cavity within a pouch called scrotum. 
? Scrotum provides low temperature required for spermatogenesis. 
? Each testis is about 4 to 5 cm length and 2 to 3 cm width. 
? Each testis has about 250 compartments called testicular lobules. 
K C MEENA 
PGT BIOLOGY 
 KV VIKASPURI II SHIFT 
 
2 
 
? Each lobule contains one to three seminiferous tubules. 
? Seminiferous tubules lined by male germ cells and Sertoli cells. 
? Male germ cell undergoes meiosis and produce sperm. 
? Sertoli cells provide nutrition to the germ cell and the sperm. 
? In between the seminiferous tubule there is interstitial cell or Leydig cell. 
? Leydig cells produce testicular hormones called androgen (testosterone). 
Accessory ducts: 
? Includes rete testis, vasa efferentia, epididymis and vas deferens. 
? Seminiferous tubules open into vasa efferentia through rete testis. 
? The vasa efferentia leaves the testis and open into epididymis. 
? The epididymis leads to vas deferens that ascends to the abdomen through inguinal canal and loops 
over the urinary bladder. 
? Vas deferens receives a duct from seminal vesicle and opens into the urethra as the ejaculatory 
duct. 
? Urethra originates from the urinary bladder and extends through the penis to its external opening 
calledurethral meatus. 
Accessory glands: 
? Includes 
o Paired seminal vesicle 
o A prostate gland 
o Paired bulbourethral gland. 
? Secretion of these glands constitutes the seminal plasma. 
? Seminal plasma rich in fructose, calcium, and certain enzyme. 
? Secretion of bulbo-urethral glands helps in lubrication of penis. 
External genitalia: 
? Penis is the external genitalia. 
? It is made of special tissue that helps in erection of the penis to facilitate insemination. 
? The enlarged end of penis is called glans penis. 
? Glans penis is covered by a loose fold of skin called foreskin. 
THE FEMALE REPRODUCTIVE SYSTEM 
? Located in the pelvic region of the female. 
? The female reproductive system includes: 
o A pair of ovaries 
o A pair of oviduct. 
o Uterus 
o Cervix 
o Vagina 
o External genitalia. 
o A pair of mammary gland. 
Page 3


K C MEENA 
PGT BIOLOGY 
 KV VIKASPURI II SHIFT 
 
1 
 
HUMAN REPRODUCTION 
  
THE MALE REPRODUCTIVE SYSTEM. 
          
? Located in the pelvis region. 
? Male reproductive system includes 
o A pair of testes. 
o Accessory ducts. 
o Accessory glands. 
o External genitalia 
Testes: 
  
? Located outside the abdominal cavity within a pouch called scrotum. 
? Scrotum provides low temperature required for spermatogenesis. 
? Each testis is about 4 to 5 cm length and 2 to 3 cm width. 
? Each testis has about 250 compartments called testicular lobules. 
K C MEENA 
PGT BIOLOGY 
 KV VIKASPURI II SHIFT 
 
2 
 
? Each lobule contains one to three seminiferous tubules. 
? Seminiferous tubules lined by male germ cells and Sertoli cells. 
? Male germ cell undergoes meiosis and produce sperm. 
? Sertoli cells provide nutrition to the germ cell and the sperm. 
? In between the seminiferous tubule there is interstitial cell or Leydig cell. 
? Leydig cells produce testicular hormones called androgen (testosterone). 
Accessory ducts: 
? Includes rete testis, vasa efferentia, epididymis and vas deferens. 
? Seminiferous tubules open into vasa efferentia through rete testis. 
? The vasa efferentia leaves the testis and open into epididymis. 
? The epididymis leads to vas deferens that ascends to the abdomen through inguinal canal and loops 
over the urinary bladder. 
? Vas deferens receives a duct from seminal vesicle and opens into the urethra as the ejaculatory 
duct. 
? Urethra originates from the urinary bladder and extends through the penis to its external opening 
calledurethral meatus. 
Accessory glands: 
? Includes 
o Paired seminal vesicle 
o A prostate gland 
o Paired bulbourethral gland. 
? Secretion of these glands constitutes the seminal plasma. 
? Seminal plasma rich in fructose, calcium, and certain enzyme. 
? Secretion of bulbo-urethral glands helps in lubrication of penis. 
External genitalia: 
? Penis is the external genitalia. 
? It is made of special tissue that helps in erection of the penis to facilitate insemination. 
? The enlarged end of penis is called glans penis. 
? Glans penis is covered by a loose fold of skin called foreskin. 
THE FEMALE REPRODUCTIVE SYSTEM 
? Located in the pelvic region of the female. 
? The female reproductive system includes: 
o A pair of ovaries 
o A pair of oviduct. 
o Uterus 
o Cervix 
o Vagina 
o External genitalia. 
o A pair of mammary gland. 
K C MEENA 
PGT BIOLOGY 
 KV VIKASPURI II SHIFT 
 
3 
 
                                         
Ovaries: 
? It is the primary female sex organs that produce the female gamete (ovum). 
? It also produces several steroid hormones. 
? The ovaries located in the lower abdomen. 
? Each ovary is about 2-4 cm in length. 
? Connected to the pelvic wall and uterus by ligaments. 
? Each ovary is covered by thin epithelium which encloses the ovarian stroma 
? The ovarian stroma has two zones 
? A peripheral cortex. 
? An inner medulla. 
Oviduct: 
? Oviducts, uterus and vagina constitute the female accessory ducts. 
? Each fallopian tube is about 10-12 cm long and extends from the periphery of each ovary to the 
uterus. 
? Close to the ovary the oviduct has a funnel shaped structure called infundibulum? 
? The edges of the infundibulum possess finger-like projections called fimbriae, which helps in 
collection of the ovum after ovulation. 
? The infundibulum leads to a wider part of the oviduct called ampulla. 
? The last part of the oviduct is called isthmus which joined to uterus. 
Uterus: 
? It is single and is called womb. 
? It is inverted pear shaped. 
? Attached the pelvic wall by ligaments. 
? The uterus opens into vagina through a narrow cervix. 
? The lumen of cervix is called cervical canal. 
? Cervical canal along with vagina form the birth canal. 
Page 4


K C MEENA 
PGT BIOLOGY 
 KV VIKASPURI II SHIFT 
 
1 
 
HUMAN REPRODUCTION 
  
THE MALE REPRODUCTIVE SYSTEM. 
          
? Located in the pelvis region. 
? Male reproductive system includes 
o A pair of testes. 
o Accessory ducts. 
o Accessory glands. 
o External genitalia 
Testes: 
  
? Located outside the abdominal cavity within a pouch called scrotum. 
? Scrotum provides low temperature required for spermatogenesis. 
? Each testis is about 4 to 5 cm length and 2 to 3 cm width. 
? Each testis has about 250 compartments called testicular lobules. 
K C MEENA 
PGT BIOLOGY 
 KV VIKASPURI II SHIFT 
 
2 
 
? Each lobule contains one to three seminiferous tubules. 
? Seminiferous tubules lined by male germ cells and Sertoli cells. 
? Male germ cell undergoes meiosis and produce sperm. 
? Sertoli cells provide nutrition to the germ cell and the sperm. 
? In between the seminiferous tubule there is interstitial cell or Leydig cell. 
? Leydig cells produce testicular hormones called androgen (testosterone). 
Accessory ducts: 
? Includes rete testis, vasa efferentia, epididymis and vas deferens. 
? Seminiferous tubules open into vasa efferentia through rete testis. 
? The vasa efferentia leaves the testis and open into epididymis. 
? The epididymis leads to vas deferens that ascends to the abdomen through inguinal canal and loops 
over the urinary bladder. 
? Vas deferens receives a duct from seminal vesicle and opens into the urethra as the ejaculatory 
duct. 
? Urethra originates from the urinary bladder and extends through the penis to its external opening 
calledurethral meatus. 
Accessory glands: 
? Includes 
o Paired seminal vesicle 
o A prostate gland 
o Paired bulbourethral gland. 
? Secretion of these glands constitutes the seminal plasma. 
? Seminal plasma rich in fructose, calcium, and certain enzyme. 
? Secretion of bulbo-urethral glands helps in lubrication of penis. 
External genitalia: 
? Penis is the external genitalia. 
? It is made of special tissue that helps in erection of the penis to facilitate insemination. 
? The enlarged end of penis is called glans penis. 
? Glans penis is covered by a loose fold of skin called foreskin. 
THE FEMALE REPRODUCTIVE SYSTEM 
? Located in the pelvic region of the female. 
? The female reproductive system includes: 
o A pair of ovaries 
o A pair of oviduct. 
o Uterus 
o Cervix 
o Vagina 
o External genitalia. 
o A pair of mammary gland. 
K C MEENA 
PGT BIOLOGY 
 KV VIKASPURI II SHIFT 
 
3 
 
                                         
Ovaries: 
? It is the primary female sex organs that produce the female gamete (ovum). 
? It also produces several steroid hormones. 
? The ovaries located in the lower abdomen. 
? Each ovary is about 2-4 cm in length. 
? Connected to the pelvic wall and uterus by ligaments. 
? Each ovary is covered by thin epithelium which encloses the ovarian stroma 
? The ovarian stroma has two zones 
? A peripheral cortex. 
? An inner medulla. 
Oviduct: 
? Oviducts, uterus and vagina constitute the female accessory ducts. 
? Each fallopian tube is about 10-12 cm long and extends from the periphery of each ovary to the 
uterus. 
? Close to the ovary the oviduct has a funnel shaped structure called infundibulum? 
? The edges of the infundibulum possess finger-like projections called fimbriae, which helps in 
collection of the ovum after ovulation. 
? The infundibulum leads to a wider part of the oviduct called ampulla. 
? The last part of the oviduct is called isthmus which joined to uterus. 
Uterus: 
? It is single and is called womb. 
? It is inverted pear shaped. 
? Attached the pelvic wall by ligaments. 
? The uterus opens into vagina through a narrow cervix. 
? The lumen of cervix is called cervical canal. 
? Cervical canal along with vagina form the birth canal. 
K C MEENA 
PGT BIOLOGY 
 KV VIKASPURI II SHIFT 
 
4 
 
? The wall of the uterus has three layers of tissues 
o Perimetrium: external thin membranous. 
o Myometrium: middle thick layer of smooth muscles 
o Endometrium: inner glandular layer. 
? Endometrium undergoes cyclical changes during menstrual cycle. 
? Myometrium exhibits strong contraction during delivery of the baby. 
  
External genitalia: 
? It includes following structure: 
o Mons Pubis: cushion of fatty covered by skin and pubic hair. 
o Labia majora: fleshy folds of tissue which extends down from the mons pubis and surrounds the 
vaginal opening. 
o Labia minora: are paired folds of tissue under the labia majora. 
o Hymen: the opening of vagina is often covered partially by a membrane called hymen. 
o Clitoris: a tiny finger-like structure lies at the upper junction of two labia minora above the 
urethral opening. 
Mammary glands: 
? Mammary gland consists of glandular tissue and fat. 
? Glandular tissue of each breast divided into 15-20 mammary lobes. 
? Mammary lobes contain cluster of cells called alveoli. 
? The cells of alveoli secrete milk, stored in the lumen of alveoli. 
? The alveoli open into mammary tubules. 
? The tubules of each lobe join to form a mammary duct. 
? Several mammary ducts join to form a wider mammary ampulla. 
? Mammary ampulla connected to lactiferous duct, through which milk is sucked out. 
GAMETOGENESIS: (formation of gametes) 
Spermatogenesis: 
? Formation of sperm from the germ cell in the testes is spermatogenesis. 
? The process begins at puberty. 
? Spermatogonia present in the lining of seminiferous tubules undergo mitotic division to increase their 
number. 
? Each spermatogonium is diploid (2n) which contain 46 chromosomes. 
? Innermost layer of spermatogonial becomes larger called primary spermatocyte. 
? Primary spermatocyte undergoes meiosis-I to form two equal haploid (n) secondary spermatocytes (n). 
? Each secondary spermatocyte undergoes meiosis-II to form two equal, haploid spermatids. 
? Each primary spermatocyte produces four spermatids. 
? Spermatids transformed into spermatozoa (sperms) by the process called spermiogenesis. 
? The sperm head embedded in the Sertoli cell. 
? Release of sperm from the seminiferous tubule is called spermiation. 
Page 5


K C MEENA 
PGT BIOLOGY 
 KV VIKASPURI II SHIFT 
 
1 
 
HUMAN REPRODUCTION 
  
THE MALE REPRODUCTIVE SYSTEM. 
          
? Located in the pelvis region. 
? Male reproductive system includes 
o A pair of testes. 
o Accessory ducts. 
o Accessory glands. 
o External genitalia 
Testes: 
  
? Located outside the abdominal cavity within a pouch called scrotum. 
? Scrotum provides low temperature required for spermatogenesis. 
? Each testis is about 4 to 5 cm length and 2 to 3 cm width. 
? Each testis has about 250 compartments called testicular lobules. 
K C MEENA 
PGT BIOLOGY 
 KV VIKASPURI II SHIFT 
 
2 
 
? Each lobule contains one to three seminiferous tubules. 
? Seminiferous tubules lined by male germ cells and Sertoli cells. 
? Male germ cell undergoes meiosis and produce sperm. 
? Sertoli cells provide nutrition to the germ cell and the sperm. 
? In between the seminiferous tubule there is interstitial cell or Leydig cell. 
? Leydig cells produce testicular hormones called androgen (testosterone). 
Accessory ducts: 
? Includes rete testis, vasa efferentia, epididymis and vas deferens. 
? Seminiferous tubules open into vasa efferentia through rete testis. 
? The vasa efferentia leaves the testis and open into epididymis. 
? The epididymis leads to vas deferens that ascends to the abdomen through inguinal canal and loops 
over the urinary bladder. 
? Vas deferens receives a duct from seminal vesicle and opens into the urethra as the ejaculatory 
duct. 
? Urethra originates from the urinary bladder and extends through the penis to its external opening 
calledurethral meatus. 
Accessory glands: 
? Includes 
o Paired seminal vesicle 
o A prostate gland 
o Paired bulbourethral gland. 
? Secretion of these glands constitutes the seminal plasma. 
? Seminal plasma rich in fructose, calcium, and certain enzyme. 
? Secretion of bulbo-urethral glands helps in lubrication of penis. 
External genitalia: 
? Penis is the external genitalia. 
? It is made of special tissue that helps in erection of the penis to facilitate insemination. 
? The enlarged end of penis is called glans penis. 
? Glans penis is covered by a loose fold of skin called foreskin. 
THE FEMALE REPRODUCTIVE SYSTEM 
? Located in the pelvic region of the female. 
? The female reproductive system includes: 
o A pair of ovaries 
o A pair of oviduct. 
o Uterus 
o Cervix 
o Vagina 
o External genitalia. 
o A pair of mammary gland. 
K C MEENA 
PGT BIOLOGY 
 KV VIKASPURI II SHIFT 
 
3 
 
                                         
Ovaries: 
? It is the primary female sex organs that produce the female gamete (ovum). 
? It also produces several steroid hormones. 
? The ovaries located in the lower abdomen. 
? Each ovary is about 2-4 cm in length. 
? Connected to the pelvic wall and uterus by ligaments. 
? Each ovary is covered by thin epithelium which encloses the ovarian stroma 
? The ovarian stroma has two zones 
? A peripheral cortex. 
? An inner medulla. 
Oviduct: 
? Oviducts, uterus and vagina constitute the female accessory ducts. 
? Each fallopian tube is about 10-12 cm long and extends from the periphery of each ovary to the 
uterus. 
? Close to the ovary the oviduct has a funnel shaped structure called infundibulum? 
? The edges of the infundibulum possess finger-like projections called fimbriae, which helps in 
collection of the ovum after ovulation. 
? The infundibulum leads to a wider part of the oviduct called ampulla. 
? The last part of the oviduct is called isthmus which joined to uterus. 
Uterus: 
? It is single and is called womb. 
? It is inverted pear shaped. 
? Attached the pelvic wall by ligaments. 
? The uterus opens into vagina through a narrow cervix. 
? The lumen of cervix is called cervical canal. 
? Cervical canal along with vagina form the birth canal. 
K C MEENA 
PGT BIOLOGY 
 KV VIKASPURI II SHIFT 
 
4 
 
? The wall of the uterus has three layers of tissues 
o Perimetrium: external thin membranous. 
o Myometrium: middle thick layer of smooth muscles 
o Endometrium: inner glandular layer. 
? Endometrium undergoes cyclical changes during menstrual cycle. 
? Myometrium exhibits strong contraction during delivery of the baby. 
  
External genitalia: 
? It includes following structure: 
o Mons Pubis: cushion of fatty covered by skin and pubic hair. 
o Labia majora: fleshy folds of tissue which extends down from the mons pubis and surrounds the 
vaginal opening. 
o Labia minora: are paired folds of tissue under the labia majora. 
o Hymen: the opening of vagina is often covered partially by a membrane called hymen. 
o Clitoris: a tiny finger-like structure lies at the upper junction of two labia minora above the 
urethral opening. 
Mammary glands: 
? Mammary gland consists of glandular tissue and fat. 
? Glandular tissue of each breast divided into 15-20 mammary lobes. 
? Mammary lobes contain cluster of cells called alveoli. 
? The cells of alveoli secrete milk, stored in the lumen of alveoli. 
? The alveoli open into mammary tubules. 
? The tubules of each lobe join to form a mammary duct. 
? Several mammary ducts join to form a wider mammary ampulla. 
? Mammary ampulla connected to lactiferous duct, through which milk is sucked out. 
GAMETOGENESIS: (formation of gametes) 
Spermatogenesis: 
? Formation of sperm from the germ cell in the testes is spermatogenesis. 
? The process begins at puberty. 
? Spermatogonia present in the lining of seminiferous tubules undergo mitotic division to increase their 
number. 
? Each spermatogonium is diploid (2n) which contain 46 chromosomes. 
? Innermost layer of spermatogonial becomes larger called primary spermatocyte. 
? Primary spermatocyte undergoes meiosis-I to form two equal haploid (n) secondary spermatocytes (n). 
? Each secondary spermatocyte undergoes meiosis-II to form two equal, haploid spermatids. 
? Each primary spermatocyte produces four spermatids. 
? Spermatids transformed into spermatozoa (sperms) by the process called spermiogenesis. 
? The sperm head embedded in the Sertoli cell. 
? Release of sperm from the seminiferous tubule is called spermiation. 
K C MEENA 
PGT BIOLOGY 
 KV VIKASPURI II SHIFT 
 
5 
 
                                                        
Hormonal control of spermatogenesis: 
? This process is initiated at puberty due to secretion of gonadotrophins releasing hormone (GnRH) 
? GnRH secreted form hypothalamus and stimulate anterior pituitary to secrete two gonadotrophins. 
o Luteinizing hormone (LH) and 
o Follicle stimulating Hormone (FSH) 
? LH acts on Leydig cells and stimulates synthesis of androgens. 
? Androgen stimulates spermatogenesis. 
? FSH acts on Sertoli cells and stimulates spermatogenesis in other ways. 
Structure of sperm: 
                                                  
? Ultrastructure of sperm consists of a head, neck, a middle piece and a tail. 
? Whole body of sperm surrounded by plasma membrane. 
? The sperm head contain an elongated haploid nucleus.