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LOGO www.themegallery.com Reproductive System YaoYang, Physiology department of SMC

LOGO Reproductive System YaoYang, Physiology department of SMC

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Page 1: LOGO  Reproductive System YaoYang, Physiology department of SMC

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Reproductive SystemYaoYang, Physiology department of SMC

Page 2: LOGO  Reproductive System YaoYang, Physiology department of SMC

The term “reproduction” usually means formation of new living entities, which closely resemble to the parent species.

In higher animals, reproduction is accomplished by activities of both sexual organs of male and female.

The processes are very complex including production of sperms and ova, sexual intercourse, fertilization of ovum, pregnancy, development of fetus and lactation.

Page 3: LOGO  Reproductive System YaoYang, Physiology department of SMC

Section 1 Reproductive and Hormonal Functions of the Male

Page 4: LOGO  Reproductive System YaoYang, Physiology department of SMC

Functions of testes:

spermatogenesis in seminiferous tubules

secrete hormones:

leydig cell-testosterone Sertoli cell-inhibin.

TestesProduce 2-4 million sperm every day Outside body – why?

Sperm like temps 1-2 cooler than body temp

Page 5: LOGO  Reproductive System YaoYang, Physiology department of SMC

I. Endocrine Function of Testes

1. Androgens

Testes secrete several male sex hormones, which are collectively called androgens, including testosterone, dihydrotesterone and androstenedione.

Testosterone is so much more abundant than the others that one can consider it the significant testicular hormone.

Page 6: LOGO  Reproductive System YaoYang, Physiology department of SMC

(1) Functions of testosterone

1) Maintenance of spermatogenesis

2) Stimulation of development of genitalia.

3) Development and maintenance of the male secondary sexual characteristics.

4) Maintenance of libido.

5) Effect on metabolism.

increases anabolism of protein,

causes growth of the bones in the thickness,

deposition of calcium salts

enhancement of production of red cells.

Page 7: LOGO  Reproductive System YaoYang, Physiology department of SMC

2. Inhibin

Inhibin, a glycoprotein with a molecular weight of 31,000-32,000, has a potent inhibitory effect on FSH secretion by pituitary gland.

The effect of inhibin on hypothalamus is slightly inhibitory in GnRH secretion.

Page 8: LOGO  Reproductive System YaoYang, Physiology department of SMC

II. Regulation of Testis Function

1. Hypothalamic-Pituitary-Testis Axis

(1) GnRH

stimulate the synthesis and release the two gonadotropins, LH and FSH.

Hypothalamus

GnRH

Anterior pituatory

FSH L H

testisLeydigSertoilseminiferous

tubules

T

inhibin

sperm

ABPE2

(2) LH (Luteinizing hormone)

LH causes interstitial cell of Leydig to synthesize testosterone by activating the cAMP second message system and to release testosterone.

Page 9: LOGO  Reproductive System YaoYang, Physiology department of SMC

(3) FSH (follicle stimulating hormone)

FSH stimulates Sertoli cells to produce ABP (androgen binding protein).

ABP binds with testosterone and enters the seminiferous tubule, increasing the androgen concentration in tubule and promoting spermatogenesis.

FSH stimulates Sertoil cell to produce and secrete inhibin, which plays a negative feedback mechanism for control of testis function.

Page 10: LOGO  Reproductive System YaoYang, Physiology department of SMC

2 Inhibin

Inhibin has a strong direct effect on the anterior pituitary gland in inhibiting FSH secretion and a slight effect on the hypothalamus in inhibiting GnRH secretion.

These automatic feedback mechanisms can maintain a normal speed of spermatiogenesis, which is required for male reproduction function.

Page 11: LOGO  Reproductive System YaoYang, Physiology department of SMC

Section 2 Reproductive and Hormonal Functions of the Female

Page 12: LOGO  Reproductive System YaoYang, Physiology department of SMC

Organs and Function Ovaries –2 female sex glands

Produce egg cells Produces the hormone, estrogen

Uterus Muscular pear-shaped organ Where baby develops Fallopian Tubes

Egg travels through these 2 tubes to the uterus

Cervix Opening between the uterus & vagina Vagina Muscular tunnel from cervix to outside

Page 13: LOGO  Reproductive System YaoYang, Physiology department of SMC

I. Menstruation, Ovulation and Hormonal Regulation

The normal reproductive years of the female are characterized by monthly rhythmical changes of secretion of the female hormones and corresponding changes in the ovaries and sexual organs.

This rhythmical pattern is called the female sexual cycle of menstrual cycle, which may be regarded as periodic preparation for fertilization and pregnancy.

Its most conspicuous feature is the periodic vaginal bleeding that occurs with the shedding of the uterine mucosa, which is known as menstruation.

.

Page 14: LOGO  Reproductive System YaoYang, Physiology department of SMC

Uterine Cycle

Proliferative phase (estrogen phase)Secretary phase (progesterone phase)Menstruation

Page 15: LOGO  Reproductive System YaoYang, Physiology department of SMC

Ovarian Cycle

Follicular phase

Ovulation

Luteal phase

Page 16: LOGO  Reproductive System YaoYang, Physiology department of SMC
Page 17: LOGO  Reproductive System YaoYang, Physiology department of SMC

II. Endocrine Functions of Ovaries

1. Functions of Estrogen

(1) On sexual organs.

The principle function of estrogen is to cause cellular proliferation and growth of the tissues of the sex organs and other tissues related to production.

Estrogen stimulates the development of sexual organs including ovaries, fallopian tubes, uterus, vagina and the external genitalia.

Page 18: LOGO  Reproductive System YaoYang, Physiology department of SMC

(2) On secondary female sexual characteristics.

Estrogen stimulates development of the secondary sex characteristics of female such as feminine figure, soft and smooth skin.

It cause the breast to grow and to show mature appearance.

(3) On metabolism.

Estrogen causes a slight increase in total body protein, which result in growth-promoting effect on the sexual organs, the bones, the breasts and a few other tissues.

Estrogen has a slight effect on retention of water and sodium by the kidney tubules.

Page 19: LOGO  Reproductive System YaoYang, Physiology department of SMC

2. Progesterone(1)Effect on uterus.

Progesterone promote secretary changes in the uterine endometrium, thus preparing the uterus for implantation of the fertilized ovum and providing nutrition for the early dividing ovum.

Progesterone decreases excitability and sensitivity to oxytocin of myometrium.

It decreases the frequency and intensity of uterine contractions, thereby helping to prevent expulsion of the implanted ovum.

Page 20: LOGO  Reproductive System YaoYang, Physiology department of SMC

(2) Effect on breasts.

Progesterone promotes development of the tubules and alveoli of the breasts, causing the alveolar cells to proliferate, enlarge, and become secretary nature but not to secrete milk.

(3) Thermogenic effect.

Progesterone causes thermogenic effect and is responsible for the rise in basal body temperature at the time of ovulation.

(4) Progesterone relaxes the smooth muscle of the blood vessels and digestive tracts.

Page 21: LOGO  Reproductive System YaoYang, Physiology department of SMC
Page 22: LOGO  Reproductive System YaoYang, Physiology department of SMC

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