Sex Organs and Hormonal Control. Male Reproductive System.

Sex Organs and Hormonal Control

Male Reproductive System

Testis

Testis

Sperm

head

nucleus

tail

Male Structure and Function 1 Structure Function

  Site of sperm and testosterone production

  Outer area of the testis

  Tubes in the testis where sperm are produced from sperm mother cells during meiosis.

  Located between the seminiferous tubules in the testis. Produce testosterone, which passes directly in to the blood.  Tube through which spermatozoa is ejaculated and urine is excreted.

  Consists of erectile tissue and blood vessels. The urethra is extended into the penis.

TESTIS

EPIDIDYMIS

SEMINIFEROUS TUBULES

INTERSTITIAL CELLS

URETHRA

PENIS

Male Structure and Function 2

  Secretes a viscous liquid rich in fructose and prostagladins. Fructose provides sperm with the energy required to swim.Prostagladins are hormone-like compounds, which stimulate contractions of the female’s reproductive tract.  Secretes a thin lubricating liquid containing enzymes whose actions maintain the fluid medium at the optimum viscosity for sperm mobility.

  Tube through which spermatozoa leave the testis and enter the urethra.

SEMINAL VESICLE

PROSTATE GLAND

SPERM DUCT

Female Reproductive System

Female Reproductive System

Ovary

Female Structure and Function 1

Structure Function

  Site of ovum/egg production through meiotic division.

  Embryo develops here

  Neck of the uterus

  Site of fertilisation. Tube through which sperm swim to the egg and through which the egg is propelled down towards the uterus.  Lining of the uterus

  Birth canal. Area of the female’s body where the male’s penis enters

OVARY

UTERUS

CERVIX

OVIDUCT

ENDOMETRIUM

VAGINA

Female Structure and Function 2

Structure Function

Graafian follicle Encloses the developing ovum and secretes ______________________

Corpus luteum Develops after ovulation and secretes ______________________

oestrogen

progesterone

Notes• The male sex cells are ……………. They are produced

in the ………… This is also where the male sex hormone ……………… is produced. Sperm are formed by ……………… in the seminiferous tubules which join together and connect to the …………………… Testosterone is produced by ………………… ……………… between the seminiferous tubules and passes directly into the blood stream. Sperm are motile. This requires a …………… medium and a source of ………………… Fertilisation takes place in the …………………… Semen is a fluid produced by the seminal vesicles that contains ………………… and ………………… It also contains ………………… secreted from the prostate gland. Fructose provides energy, prostaglandins stimulate contraction of the female reproductive tract helping sperm to reach the oviduct faster. Enzymes maintain ……………… of the fluid medium.

Notes

• The female sex cell is the ………… (ovum). They are formed by …………… in the ……………… The egg is contained in a ……………… ……………… This secretes the female sex hormone …………………… After the egg has been released (…………………..), the follicle develops into a corpus luteum which secretes the sex hormone …………………………

Notes (answers)• The male sex cells are sperm. They are produced in

the testes. This is also where the male sex hormone testosterone is produced. Sperm are formed by meiosis in the seminiferous tubules which join together and connect to the sperm duct Testosterone is produced by interstitial cells between the seminiferous tubules and passes directly into the blood stream. Sperm are motile. This requires a fluid medium and a source of energy. Fertilisation takes place in the oviduct. Semen is a fluid produced by the seminal vesicles that contains fructoseandprostaglandins It also contains enzymes secreted from the prostate gland. Fructose provides energy, prostaglandins stimulate contraction of the female reproductive tract helping sperm to reach the oviduct faster. Enzymes maintain viscosity of the fluid medium.

Notes (answers)

• The female sex cell is the egg (ovum). They are formed by meiosis in the ovaries. The egg is contained in a graafian follicle. This secretes the female sex hormone oestrogen. After the egg has been released (ovulation), the follicle develops into a corpus luteum which secretes the sex hormone progesterone.

Gonadotrophic Hormones

• These are secreted by the pituitary gland in the brain.

• They target the reproductive organs and are carried by the blood.

• Female gonadotrophic hormones are FSH (follicle stimulating hormone) and LH (luteinising hormone).

• Male gonadotrophic hormones are FSH and ICSH (interstitial cell stimulating hormone)

Male Gonadotrophins

• FSH targets the testis and promotes sperm production in the seminiferous tubules.

• ICSH targets the testis and stimulates the interstitial cells to produce testosterone (which also stimulates sperm production). It also stimulates secretions by the prostate gland and seminal vesicles.

Self Regulation of Testosterone

Female Gonadotrophins

• FSH targets the ovaries and stimulates the development and maturation of the Graafian follicle. It also stimulates the secretion of oestrogen by the ovary tissue.

• LH triggers ovulation. It also brings about the development of the corpus luteum and the secretion of progesterone.

Influence of Pituitary Hormones

Influence of Ovarian Hormones

• Oestrogen stimulates proliferation of the endometrium. It also stimulates the secretion of LH by the pituitary.

• Progesterone promotes thickening of the endometrium. It also inhibits the secretion of FSH and LH by the pituitary

Effect of Progesterone

Male Hormones SummaryHormon

eSecreted from Target area Effect

FSH      

ICSH      

Testosterone

ANTERIOR PITUITARY

SEMINIFEROUS TUBULES (TESTES)

SPERM PRODUCTION

ANTERIOR PITUITARY

INTERSTITIAL CELLS

(TESTES)

TESTOSTERONE PRODUCTION

INTERSTITIAL CELLS

(TESTES)

SEMINIFEROUS TUBULES (TESTES)

SPERM PRODUCTION

Female Hormone SummaryHormone Secreted from Target area Effect

FSH      

LH      

Oestrogen      

Progesterone      

ANTERIOR PITUITARY

OVARY MATURATION OF FOLLICLE

ANTERIOR PITUITARY

OVARYTRIGGERS

OVULATION AND DEVELOPMENT OF CORPUS LUTEUM

OVARIAN TISSUE (GRAAFIAN FOLLICLE)

UTERUS AND ANTERIOR PITUITARY

PROLIFERATION OF ENDOMETRIUM

AND SECRETION OF LH

CORPUS LUTEUMUTERUS AND

ANTERIOR PITUITARY

THICKENING OF ENDOMETRIUM AND INHIBITS SECRETION

OF FSH AND LH

1 5 14 28

oocyte

prim aryfollicle

corpusluteum

m enses follicular phase luteal or secretory phase

OVARY

UTERUS(thickness of

endom etrium )

Tim e (days)

m enstruation

1 2 3 4 5 6 7 8 9 10 11 12 13 14 1516 17 18 19 20 21 22 23 25 26 27 28

Concentration ofFSH and LH

in blood

Concentration ofoestrogens and

progesteronein blood

new cycle

developingfollicles

ovulation

OESTROGENS

PROGESTERONE &SOM E OESTROGENS

FSH

LH

oestrogens progesterone

Fertilisation• Nuclei of male and female gamete

fuse together to form a zygote.

Fertilisation

After fertilisation the egg secretes HCG (human chorionic gonadotrophin) which maintains the corpus luteum which secretes progesterone and prevents menstruation. After 6 weeks the placenta secretes progestrone

Cervix

• Cells which line the cervix secrete mucus which lubricates the vagina.

• Mucus secretion is stimulated by oestrogen.

• High levels of progesterone in the luteal phase causing the mucus to become more viscous and during pregnancy it forms a ‘plug’ to protect the fertilised egg from infection.

Body Temp Changes

• At ovulation, the body temp rises by about 0.5oC.

• It remains at this high level during the luteal phase.

Fertility

• Men are continuously fertile due to a steady quantity of testosterone production.

• Women have cyclical fertility and are only fertile 3/4days following ovulation.