Sex Organs and Hormonal Control

Male Reproductive System

Testis

Testis

Sperm tail head nucleus

Male Structure and Function 1   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   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 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 Summary SEMINIFEROUS TUBULES (TESTES) ANTERIOR PITUITARY Secreted from Target area Effect FSH   ICSH Testosterone SEMINIFEROUS TUBULES (TESTES) ANTERIOR PITUITARY SPERM PRODUCTION ANTERIOR PITUITARY INTERSTITIAL CELLS (TESTES) TESTOSTERONE PRODUCTION INTERSTITIAL CELLS (TESTES) SEMINIFEROUS TUBULES (TESTES) SPERM PRODUCTION

Female Hormone Summary Secreted from Target area Effect FSH   LH Oestrogen Progesterone ANTERIOR PITUITARY OVARY MATURATION OF FOLLICLE TRIGGERS OVULATION AND DEVELOPMENT OF CORPUS LUTEUM ANTERIOR PITUITARY OVARY OVARIAN TISSUE (GRAAFIAN FOLLICLE) UTERUS AND ANTERIOR PITUITARY PROLIFERATION OF ENDOMETRIUM AND SECRETION OF LH THICKENING OF ENDOMETRIUM AND INHIBITS SECRETION OF FSH AND LH UTERUS AND ANTERIOR PITUITARY CORPUS LUTEUM

LH FSH progesterone oestrogens

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.