HUMAN REPRODUCTION
- Sexual reproduction is the process by which new organisms are created, by combining genetic information from
two individuals of different sexes.
-Sexual dimorphism is evident in human beings i.e male and female individuals are separately distinguishable.
-
Human beings are unisexual, male produce gametes in old age also in case of women the formation of ovum stops at
the age of 50 years.
Male reproductive system:
It has
1. A pair testes
2. Accessory ducts
3. Male accessory glands
4. External genetalia.
Testes:
The testes are situated outside the abdominal cavity within a pouch
called scrotum.
The scrotum helps in maintaining the low temperature of the testes
(2–2.5o C lower than the normal internal body temperature)
necessary for spermatogenesis.
In adults, each testis is oval in shape, with a length of about 4 to 5
cm and a width of about 2 to 3 cm. The testis is covered by a dense
covering.
Each testis has about 250 compartments called testicular lobules.
Each lobule contains one to three highly coiled seminiferous tubules in which sperms are produced.
Seminiferous tubule:
This is the site where sperms are produced.
Each seminiferous tubule is lined on its inside by two types of cells
called
i. Male germ cells (spermatogonia)
ii. Sertoli cells (Nurse cells)
The male germ cells undergo meiotic divisions finally leading to
sperm formation, while Sertoli cells provide nutrition to the germ
cells.
Leydig cells (Interstitial cells)
The regions outside the seminiferous tubules called interstitial spaces
contain small blood vessels and interstitial cells or Leydig cells.
Leydig cells synthesise and secrete testicular hormones called androgens.
Accessory ducts:
1. Rete testis
2. Vasa efferentia
3. Epididymes
4. Vas deferens
5. Urethra
The seminiferous tubules of the testes open into the vasa efferentia through rete testis.
The vasa efferentia leave the testis and opens into epididymes located along the posterior surface of
each testis.
The epididymis leads to vas deferens that ascends to the abdomen and loops over the urinary bladder.
, Vas deferns receives a duct from seminal vesicle and opens into urethra as the ejaculatory duct.
These ducts store and transport the sperms from the testis to the outside through urethra.
The urethra originates from the urinary bladder and extends through the penis to its external opening
called urethral meatus.
Seminiferous Vasa Vas
epididymes Urethra
tubules efferentia deferens
Functions of the male accessory ducts:
The store and transport the sperms from the testes to the outside through the urethra.
Male external genetalia:
The penis is the male external genitalia. It is made up of special tissue that helps in erection of the
penis to facilitate insemination.
The enlarged end of penis called the glans penis is covered by a loose fold of skin called foreskin.
Male accessory glands:
The male accessory glands include paired
1. seminal vesicles
2. a prostate
3. Paired bulbourethral glands
Functions of male accessory sex glands:
Secretions of these glands constitute the seminal plasma which is rich in fructose, calcium and certain
enzymes.
The secretions of bulbourethral glands also help in the lubrication of the penis.
The seminal plasma when it is mixed with sperms, it is said to be semen.
Female reproductive system:
The female reproductive system consists of
1. A pair of ovaries
2. A pair of oviducts
3. Uterus
4. Cervix
5. Vagina
6. External genitalia
7. Mammary glands
Ovary:
Ovary is the primary female sex organ that produces the female gamete (ovum) and several steroid
hormones (ovarian hormones).
The ovaries are located one on each side of the lower abdomen.
Each ovary is about 2 to 4 cm in length and is connected to
the pelvic wall and uterus by ligaments.
Each ovary is covered by a thin epithelium which encloses
the ovarian stroma.
The stroma is divided into two zones – a peripheral cortex
and an inner medulla.
Oviduct:
The oviducts (fallopian tubes), 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.
Parts of oviduct:
- Sexual reproduction is the process by which new organisms are created, by combining genetic information from
two individuals of different sexes.
-Sexual dimorphism is evident in human beings i.e male and female individuals are separately distinguishable.
-
Human beings are unisexual, male produce gametes in old age also in case of women the formation of ovum stops at
the age of 50 years.
Male reproductive system:
It has
1. A pair testes
2. Accessory ducts
3. Male accessory glands
4. External genetalia.
Testes:
The testes are situated outside the abdominal cavity within a pouch
called scrotum.
The scrotum helps in maintaining the low temperature of the testes
(2–2.5o C lower than the normal internal body temperature)
necessary for spermatogenesis.
In adults, each testis is oval in shape, with a length of about 4 to 5
cm and a width of about 2 to 3 cm. The testis is covered by a dense
covering.
Each testis has about 250 compartments called testicular lobules.
Each lobule contains one to three highly coiled seminiferous tubules in which sperms are produced.
Seminiferous tubule:
This is the site where sperms are produced.
Each seminiferous tubule is lined on its inside by two types of cells
called
i. Male germ cells (spermatogonia)
ii. Sertoli cells (Nurse cells)
The male germ cells undergo meiotic divisions finally leading to
sperm formation, while Sertoli cells provide nutrition to the germ
cells.
Leydig cells (Interstitial cells)
The regions outside the seminiferous tubules called interstitial spaces
contain small blood vessels and interstitial cells or Leydig cells.
Leydig cells synthesise and secrete testicular hormones called androgens.
Accessory ducts:
1. Rete testis
2. Vasa efferentia
3. Epididymes
4. Vas deferens
5. Urethra
The seminiferous tubules of the testes open into the vasa efferentia through rete testis.
The vasa efferentia leave the testis and opens into epididymes located along the posterior surface of
each testis.
The epididymis leads to vas deferens that ascends to the abdomen and loops over the urinary bladder.
, Vas deferns receives a duct from seminal vesicle and opens into urethra as the ejaculatory duct.
These ducts store and transport the sperms from the testis to the outside through urethra.
The urethra originates from the urinary bladder and extends through the penis to its external opening
called urethral meatus.
Seminiferous Vasa Vas
epididymes Urethra
tubules efferentia deferens
Functions of the male accessory ducts:
The store and transport the sperms from the testes to the outside through the urethra.
Male external genetalia:
The penis is the male external genitalia. It is made up of special tissue that helps in erection of the
penis to facilitate insemination.
The enlarged end of penis called the glans penis is covered by a loose fold of skin called foreskin.
Male accessory glands:
The male accessory glands include paired
1. seminal vesicles
2. a prostate
3. Paired bulbourethral glands
Functions of male accessory sex glands:
Secretions of these glands constitute the seminal plasma which is rich in fructose, calcium and certain
enzymes.
The secretions of bulbourethral glands also help in the lubrication of the penis.
The seminal plasma when it is mixed with sperms, it is said to be semen.
Female reproductive system:
The female reproductive system consists of
1. A pair of ovaries
2. A pair of oviducts
3. Uterus
4. Cervix
5. Vagina
6. External genitalia
7. Mammary glands
Ovary:
Ovary is the primary female sex organ that produces the female gamete (ovum) and several steroid
hormones (ovarian hormones).
The ovaries are located one on each side of the lower abdomen.
Each ovary is about 2 to 4 cm in length and is connected to
the pelvic wall and uterus by ligaments.
Each ovary is covered by a thin epithelium which encloses
the ovarian stroma.
The stroma is divided into two zones – a peripheral cortex
and an inner medulla.
Oviduct:
The oviducts (fallopian tubes), 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.
Parts of oviduct:
