Reproduction is the production of young ones by an organism. Humans are sexually reproducing and viviparous.
HUMAN REPRODUCTIVE SYSTEM
1. Male Reproductive System b. Accessory ducts (Duct system)
- It consists of paired testes, Accessory ducts, Accessory - Include rete testis, vasa efferentia, epididymis & vas
glands & external genitalia (penis). deferens. They conduct sperms from testis as follows:
- Seminiferous tubules → rete testis (irregular cavities) →
vasa efferentia (series of fine tubules) → epididymis
(stores sperms temporarily) → vas deferens → join with
duct of seminal vesicle to form ejaculatory duct →
urethra → urethral meatus.
- Urethra receives ducts of prostate and Cowper’s glands.
c. Accessory glands
- Include a prostate gland, a pair of seminal vesicles and a
pair of Cowper’s glands (bulbo-urethral glands).
- Their collective secretion (seminal plasma) is rich in
fructose, Ca and enzymes.
- Seminal plasma + sperms → semen.
- Functions of seminal plasma:
• Helps for transporting sperms.
• Supplies nutrients to sperms.
• Provides alkalinity to counteract the acidity of uterus.
• Secretions of Cowper’s glands lubricate the penis.
- Secretions of epididymis, vas deferens, seminal vesicle &
prostate help for maturation and motility of sperms.
a. Paired testes d. Penis (external genitalia)
- Primary sex organs that produce sperms & testosterone. - It is a copulatory organ made of erectile spongy tissue.
- Testes are formed within the abdomen. Soon after the birth - When spongy tissue is filled with blood, the penis erects. It
or at the 8th month of pregnancy they descent into the facilitates insemination.
scrotal sac (scrotum) through inguinal canal. - The cone-shaped tip of the penis is called glans penis. It is
- The low temperature (2-2.50 C less than the body covered by prepuce (foreskin).
temperature) of scrotum helps for proper functioning of 2. Female Reproductive System
testes and for spermatogenesis.
It includes Ovaries, Accessory ducts & External genitalia.
- Each testis is oval shaped. Length 4-5 cm, width: 2-3 cm.
- Each testis has about 250 testicular lobules.
- Each lobule contains 1-3 coiled seminiferous tubules.
- Seminiferous tubule is lined internally with spermatogonia
(male germ cells) & Sertoli cells (supporting cells).
- Sertoli cells give shape and nourishment to developing
spermatogonia.
- The regions outside the seminiferous tubules (interstitial
spaces) contain small blood vessels, interstitial cells
(Leydig cells) and immunologically competent cells.
- Leydig cells secrete testicular hormones (androgens).
1
, a. Paired ovaries c. External genitalia (vulva or pudendum)
- Primary sex organs which produce ova (female gamete) & - Consist of Mons pubis, labia majora, labia minora,
steroid ovarian hormones (estrogen & progesterone). hymen & clitoris.
- Each ovary is 2-4 cm in length. - Mons pubis: A cushion of fatty tissue covered by pubic hair.
- They are located on both side of the lower abdomen and - Labia majora: Large, fleshy, fatty and hairy outer folds.
connected to the pelvic wall and uterus by ligaments. Surrounds vaginal opening.
- Each ovary is covered by a thin epithelium which encloses - Labia minora: Small, thin and hairless inner folds.
the ovarian stroma. - Hymen (Maiden head): A membrane which partially cover
- The stroma has outer cortex and inner medulla. the vaginal opening. It is often torn during the first coitus. It
- Ovary contains groups of cells (Ovarian follicles). Each may also be broken by a sudden fall or jolt, insertion of a
follicle carries a centrally placed ovum. vaginal tampon; active participation in some sports items etc.
b. Accessory ducts (Duct system) In some women, hymen persists after coitus. So the hymen
Include 2 oviducts (Fallopian tubes), a uterus & vagina. is not a reliable indicator of virginity or sexual experience.
- Clitoris: A highly sensitive organ lying just in front of the
Ø Oviducts: Each oviduct (10-12 cm long) has 3 parts:
urethral opening.
• Infundibulum: Funnel-shaped opening provided with
many finger-like fimbriae. It helps to collect the ovum. Mammary glands (breasts)
• Ampulla: Wider part.
• Isthmus: Narrow part. It joins the uterus.
The ciliated epithelium lined the lumen of the oviduct
drives the ovum towards the uterus.
Ø Uterus (womb): It is inverted pear shaped. It is supported
by ligaments attached to the pelvic wall.
Uterus has 3 parts- Upper fundus, middle body and
terminal cervix. Cervix opens to vagina.
Cervical canal and vagina forms birth canal.
The uterine wall has 3 layers:
- A pair of mammary glands contains glandular tissue & fat.
• Perimetrium: External thin membrane.
- Glandular tissue of each breast has 15-20 mammary lobes
• Myometrium: Middle thick layer of smooth muscle.
containing clusters of cells (mammary alveoli).
• Endometrium: Inner glandular and vascular layer.
- Cells of alveoli secrete milk. It is stored in lumen of alveoli.
Ø Vagina: It opens to the exterior between urethra & anus. - The alveoli open into mammary tubules.
The lumen of vagina is lined by a glycogen-rich mucous - The tubules of each lobe join to form a mammary duct.
membrane consisting of sensitive papillae & Bartholin’s - Several mammary ducts join to form a wider mammary
glands. Bartholin’s glands secrete mucus that lubricates ampulla which is connected to lactiferous duct through
the penis during sexual act. which milk is sucked out.
GAMETOGENESIS
- It is the formation of gametes in the gonads. - 4 spermatids are formed from each primary spermatocyte.
- It is 2 types: Spermatogenesis and Oogenesis. - After spermiogenesis, sperm heads are embedded in Sertoli
1. Spermatogenesis cells to get nourishment. Then they are released to lumen
of seminiferous tubules. It is called spermiation.
It is the process of formation of sperms (spermatozoa) in
seminiferous tubules of testis. It has 2 stages:
a. Formation of spermatids: In this, Sperm mother cells
(Spermatogonia or male germ cells) produce spermatids.
b. Spermiogenesis: Spermatids transform into sperm.
Schematic representation of spermatogenesis
Spermatogonia -2n (46 chromosomes)
↓ Mitosis differentiation
Primary spermatocytes (2n)
↓ 1st meiotic division
Sec. spermatocytes -n (23) Diagrammatic sectional view of a seminiferous tubule
↓ 2nd meiotic division Role of Hormones in Spermatogenesis
Spermatids (n) - Hypothalamus releases Gonadotropin releasing hormone
↓ Differentiation (GnRH).
Spermatozoa (n)
2
HUMAN REPRODUCTIVE SYSTEM
1. Male Reproductive System b. Accessory ducts (Duct system)
- It consists of paired testes, Accessory ducts, Accessory - Include rete testis, vasa efferentia, epididymis & vas
glands & external genitalia (penis). deferens. They conduct sperms from testis as follows:
- Seminiferous tubules → rete testis (irregular cavities) →
vasa efferentia (series of fine tubules) → epididymis
(stores sperms temporarily) → vas deferens → join with
duct of seminal vesicle to form ejaculatory duct →
urethra → urethral meatus.
- Urethra receives ducts of prostate and Cowper’s glands.
c. Accessory glands
- Include a prostate gland, a pair of seminal vesicles and a
pair of Cowper’s glands (bulbo-urethral glands).
- Their collective secretion (seminal plasma) is rich in
fructose, Ca and enzymes.
- Seminal plasma + sperms → semen.
- Functions of seminal plasma:
• Helps for transporting sperms.
• Supplies nutrients to sperms.
• Provides alkalinity to counteract the acidity of uterus.
• Secretions of Cowper’s glands lubricate the penis.
- Secretions of epididymis, vas deferens, seminal vesicle &
prostate help for maturation and motility of sperms.
a. Paired testes d. Penis (external genitalia)
- Primary sex organs that produce sperms & testosterone. - It is a copulatory organ made of erectile spongy tissue.
- Testes are formed within the abdomen. Soon after the birth - When spongy tissue is filled with blood, the penis erects. It
or at the 8th month of pregnancy they descent into the facilitates insemination.
scrotal sac (scrotum) through inguinal canal. - The cone-shaped tip of the penis is called glans penis. It is
- The low temperature (2-2.50 C less than the body covered by prepuce (foreskin).
temperature) of scrotum helps for proper functioning of 2. Female Reproductive System
testes and for spermatogenesis.
It includes Ovaries, Accessory ducts & External genitalia.
- Each testis is oval shaped. Length 4-5 cm, width: 2-3 cm.
- Each testis has about 250 testicular lobules.
- Each lobule contains 1-3 coiled seminiferous tubules.
- Seminiferous tubule is lined internally with spermatogonia
(male germ cells) & Sertoli cells (supporting cells).
- Sertoli cells give shape and nourishment to developing
spermatogonia.
- The regions outside the seminiferous tubules (interstitial
spaces) contain small blood vessels, interstitial cells
(Leydig cells) and immunologically competent cells.
- Leydig cells secrete testicular hormones (androgens).
1
, a. Paired ovaries c. External genitalia (vulva or pudendum)
- Primary sex organs which produce ova (female gamete) & - Consist of Mons pubis, labia majora, labia minora,
steroid ovarian hormones (estrogen & progesterone). hymen & clitoris.
- Each ovary is 2-4 cm in length. - Mons pubis: A cushion of fatty tissue covered by pubic hair.
- They are located on both side of the lower abdomen and - Labia majora: Large, fleshy, fatty and hairy outer folds.
connected to the pelvic wall and uterus by ligaments. Surrounds vaginal opening.
- Each ovary is covered by a thin epithelium which encloses - Labia minora: Small, thin and hairless inner folds.
the ovarian stroma. - Hymen (Maiden head): A membrane which partially cover
- The stroma has outer cortex and inner medulla. the vaginal opening. It is often torn during the first coitus. It
- Ovary contains groups of cells (Ovarian follicles). Each may also be broken by a sudden fall or jolt, insertion of a
follicle carries a centrally placed ovum. vaginal tampon; active participation in some sports items etc.
b. Accessory ducts (Duct system) In some women, hymen persists after coitus. So the hymen
Include 2 oviducts (Fallopian tubes), a uterus & vagina. is not a reliable indicator of virginity or sexual experience.
- Clitoris: A highly sensitive organ lying just in front of the
Ø Oviducts: Each oviduct (10-12 cm long) has 3 parts:
urethral opening.
• Infundibulum: Funnel-shaped opening provided with
many finger-like fimbriae. It helps to collect the ovum. Mammary glands (breasts)
• Ampulla: Wider part.
• Isthmus: Narrow part. It joins the uterus.
The ciliated epithelium lined the lumen of the oviduct
drives the ovum towards the uterus.
Ø Uterus (womb): It is inverted pear shaped. It is supported
by ligaments attached to the pelvic wall.
Uterus has 3 parts- Upper fundus, middle body and
terminal cervix. Cervix opens to vagina.
Cervical canal and vagina forms birth canal.
The uterine wall has 3 layers:
- A pair of mammary glands contains glandular tissue & fat.
• Perimetrium: External thin membrane.
- Glandular tissue of each breast has 15-20 mammary lobes
• Myometrium: Middle thick layer of smooth muscle.
containing clusters of cells (mammary alveoli).
• Endometrium: Inner glandular and vascular layer.
- Cells of alveoli secrete milk. It is stored in lumen of alveoli.
Ø Vagina: It opens to the exterior between urethra & anus. - The alveoli open into mammary tubules.
The lumen of vagina is lined by a glycogen-rich mucous - The tubules of each lobe join to form a mammary duct.
membrane consisting of sensitive papillae & Bartholin’s - Several mammary ducts join to form a wider mammary
glands. Bartholin’s glands secrete mucus that lubricates ampulla which is connected to lactiferous duct through
the penis during sexual act. which milk is sucked out.
GAMETOGENESIS
- It is the formation of gametes in the gonads. - 4 spermatids are formed from each primary spermatocyte.
- It is 2 types: Spermatogenesis and Oogenesis. - After spermiogenesis, sperm heads are embedded in Sertoli
1. Spermatogenesis cells to get nourishment. Then they are released to lumen
of seminiferous tubules. It is called spermiation.
It is the process of formation of sperms (spermatozoa) in
seminiferous tubules of testis. It has 2 stages:
a. Formation of spermatids: In this, Sperm mother cells
(Spermatogonia or male germ cells) produce spermatids.
b. Spermiogenesis: Spermatids transform into sperm.
Schematic representation of spermatogenesis
Spermatogonia -2n (46 chromosomes)
↓ Mitosis differentiation
Primary spermatocytes (2n)
↓ 1st meiotic division
Sec. spermatocytes -n (23) Diagrammatic sectional view of a seminiferous tubule
↓ 2nd meiotic division Role of Hormones in Spermatogenesis
Spermatids (n) - Hypothalamus releases Gonadotropin releasing hormone
↓ Differentiation (GnRH).
Spermatozoa (n)
2
