1 / 73

Reproduction

Reproduction. Testes (male gonads) -Produce sperm -Produce sex hormones -Found in a sac called the scrotum -Suspended outside of the body cavity for temperature reduction. -Testes wall made of fibrous connective

rinam
Download Presentation

Reproduction

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Reproduction

  2. Testes (male gonads) -Produce sperm -Produce sex hormones -Found in a sac called the scrotum -Suspended outside of the body cavity for temperature reduction

  3. -Testes wall made of fibrous connective tissue (Divides the testes into lobules (Chambers) - Inside chambers are long tubes (70 cm) called the Seminiferous tubules) . - This is the actual site forspermatogenesis. - Interstitial cells secretes androgens “testosterone”

  4. Spermatogenesis –Sperm Development Sperms cells are derived from undifferentiated cells called SPERMATOGONIA (sing. Spermatogonium), which lie just on the outside wall of a tubule and divide mitotically (dividing into copies), always producing new spermatogonia.

  5. Some newly formed spermatogonia move away from the outer wall to increase in size and become primary spermatocytes, which undergo meiosis, a type of cell division. Primary spermatocytes, with 46 chromosomes, divide to give 2 secondary spermatocytes, each with 23 chromosomes.

  6. Secondary spermatocytes divide to produce 4 spermatids, also with 23 chromosomes. (see video)

  7. Spermatids then differentiate into sperm (spermatozoa). Also present in the tubules are the sertoli, which support, nourish and regulate the spermatogenic cells.

  8. Epididymus -Stores sperm as they mature Seminal Vesicle -Contributes to seminal fluid Cowper’s Gland -Pea-sized organs that lie posterior to the prostate on either side of the urethra. -Contributes to seminal fluid

  9. Prostate Gland -A single dough-nut shaped gland that surrounds the upper portion of the urethra just below the bladder.

  10. - Older men can have their prostate become enlarged and urination becomes quite painful. (surgically fixed) - Helps produce seminal fluid

  11. Urethra-Conducts sperm out of the body Ductus Vas Deferens- Conducts and stores sperm Penis-Serves as an organ of copulation

  12. Path of Sperm 1. Formed in the seminiferous tubules of the testes 2. Mature and stored in the epididymus 3. Stored in the Vas Deferens 4. Enters the urethra just prior to ejaculation 5. Accessory glands (prostate, Cowper’s gland, and seminal vesicle) add secretions to semen. 6. Semen and sperm exit through the penis.

  13. Seminal Fluid SOURCES: 1. Seminal Vesicle 2. Prostate Gland 3. Cowper’s Gland

  14. FUNCTION: Produce slightly basic pH • 7.5 preferred pH of sperm (Basic) to counteract the acidity level of the vagina. 2. Provides fructose for energy for sperm • Contains prostaglandins – chemicals which cause the uterus to contract. 4.   Aids in the movement of the sperm to the egg. 5.  Lubrication

  15. Sperm Parts Head: 23 chromosomes Acrosome attached- type of Lysosome -contains hydrolytic enzymes -digests in outer layer of egg so sperm can penetrate. Middle Piece: Contains mitochondria – for energy Tail: Used for locomotion

  16. Function of Testosterone 1. Essential for development of primary sex organs. 2. Essential for the development of sperm -spermatogenic cells take up testosterone which stimulate their activity. 3. Increased testosterone concentration at puberty causes maturation of penis and testes.

  17. 4. Secondary Sex Characteristics -facial hair -larynx expands (voice changes) -armpit hair -Increase muscular strength -pubic hair -aggression -oil and sweat -sex drive glands secrete(=Stinky)

  18. Hormonal Control of Testosterone -Hypothalamus releases GnRH (Gonadotropic releasing hormone) -GnRH causes anterior pituitary to release 2 gonadotropic hormones:

  19. FSH (Follicle stimulating hormone) -promotes spermatogenesis in the seminiferous tubules LH (Leutenizing Hormone) -promotes production of testosterone in interstitial cells.

  20. NEGATIVE FEEDBACK Increased testosterone concentration in the blood causes the anterior pituitary to make less LH, therefore less testosterone is produced. Decreased testosterone concentration in the blood causes the anterior pituitary to make more LH and therefore more testosterone is produced.

  21. Increased concentration of stored sperm causes an increase in production of inhibin and decreases production of FSH, therefore production of sperm decreases. Decreased concentration of stored sperm causes a decrease in production of inhibin and more FSH, therefore more sperm is produced.

  22. Female Reproductive System

  23. Ovaries -Produce eggs and sex hormones Uterus (Womb) -Houses developing fetus Oviduct -conducts egg towards the uterus -also called the fallopian tubes or uterine tube

  24. Fimbriae - finger-like projections of the oviducts which brush over the ovaries. -along with cilia in the oviducts, they cause a current which sweeps the egg into the oviduct Cervix -narrow end of uterus leading to the vagina -dilates at birth to allow baby to exit

  25. Vagina -Receives penis during sexual intercourse and serves as a birth canal Clitoris -female sensory organ; homologous to the male penis -provides sensitivity during intercourse Labia major and Labia minor -protective folds of skin which surround and protect the clitoris and the openings of the vagina and urethra

  26. Functions of Estrogen (Female Sex Hormone) 1. Stimulates growth of uterus and vagina at puberty 2. Egg maturation 3. Secondary Sex Characteristics: -armpit hair / pubic hair -fat distribution beneath skin -enlarged pelvic girdle (wider hips) -breast development (requires progesterone as well)

  27. Ovarian Cycles

  28. (see video) Day 1 –13 Follicular Phase • Hypothalamus produces a GnRH to stimulate Anterior lobe of pituitary • FSH and LH stimulates ovary for follicle growth from pituitary gland

  29. 3. Primary follicle (46 chromosomes) contains primary oocyte (egg cell) which divides. (produces female sex hormones) One oocyte gets most cytoplasm and 23 chromosomes. (called a secondary oocyte, which is inside the now secondary follicle)

  30. Other oocyte called the polar body disintegrates 5. The secondary follicle grows into a Grafian (vesicular) Follicle.

  31. Day 14 Ovulation 6. Grafian Follicle bursts (ovulation) LH is at its highest and triggers ovulation

  32. Day 15 –28 Luteal Phase 7. The follicle has lost its oocyte (or “egg”) and forms into the Corpus Luteum. (LH causes the corpus luteum to form.) -the corpus luteum secretes hormones -estrogen and progesterone (see video)

  33. If pregnancy (fertilization) does not occur: Corpus Luteum breaks down (about 10 days) Cycle will repeat. If pregnancy does occur: Corpus luteum remains for 3 – 6 months and continues to produce hormones.

  34. Uterine Cycle Day 1 –5 Menstruation • Low levels of sex hormones (Corpus Luteum has just disintegrated) 2. Endometrium (lining of Uterus) breaks down

  35. Cells of the endometrium, blood vessels, and blood are shedding from the uterus and exit the vagina. • A flow of blood (called menses) passes out of the vagina during a period called menstruation.

  36. Day 6 – 13 Proliferative phase 1. Increase estrogen by the ovarian follicle causes the endometrium to rebuild. 2. Endometrium becomes thick and vascularized

More Related