Reproductive systems

Reproductive systems

1. Asexual

   • BUD- hydras
   • SPLITTING IN HALF- hatworms
   • REGENERATE FROM FRAGMENTS-sponges , annelids and echinoderms

2. Sexual

   • MONOECIOUS - contain both male and female sex organs in single body and majority practice croos- fertiization with other individuals.
   • DIOECIOUS- separate sex and egg of one parent is fertilized by sperm of another
   • PARTHENOGENESIS- modification of sexual reproduction and unfertilized egg develop into a complet individual.
   • COPULATION - sexual union to facilitate the reception of sperm , resulting in internal fertilization

3. Life strategies

   • OVOVIVIPAROUS- animals retain their eggs and release young ableto fend for themselves
   • VIVIPAROUS-usually placental mammals as they do not lay eggs and development occurs inside female's body. Placental mammals eliminate need for shelled egg
   • OVIPAROUS- animals deposit eggs in external environment

4. Human male reproductive system

   • IMPORTANTS ORGANS AND ITS FUNCTION
     • BULBOURETHRAL GLANDS- contribute fluid to semen
     • SEMINAL VESICLES - contribute fluid to semen
     • VASA DEFERENTIA- conduct and store sperm
     • EPIDIDMYIDES- sites of maturation and some storage of sperm
     • TESTES- produce sperm and sex hormones
     • URETHRA- conducts sperm (and urine)
     • PROSTATE GLAND - contributes fluid to semen
     • PENIS - ogan of couplation
   • PROUCTION OF SPERMS
     • SEMINIFEROUS TUBULES is a tubes packed with cells undergoing spermatogenesis. Spermatogonia divide to produce primary spermatocytes. Primary spermatocytes undergo meiosis 1 to produce secondary spermatocytes.. Secondary spermatocytes undergo meiosis 2 to produce four spermatids , each of which matures into a sperm cell (- consist of three parts which are head- acrosome and nucleus, middle piece and tail)
     • PENIS is a cylindrical organ hanging in front of scrotum. Three cylindrical columns of spongy, erectile tissue and blood flow stiffen penis and increase its size. Semen (seminal fluid) contains sperm and secretion from seminal vesicles,prostate gland and bulbourtehral glands.
     • EJACULATION . emission- nerve impulses sent to epidiidymides and vasa deferntia. sperm enter ejaculatory duct. Secretion released by seminal vesicles, prostate gland and bulbourethral glands. Expulsion rythmical muscle contraction (expel semen in spurts from opening in urethra, contractions are part of male orgasm and average male release 2-5 mL of sperm during orgasm.
   • HORMONAL REGULATION IN MALES
     • Hypothalamus has ultimate control of testicular sexual function. -Gonadotropic-releasing hormone (GnRH) stimulates production of the gonadotropic hormones by anterior pituatary. -Follicle Stimulating Hormone promotes spermatogenesis in the semineferous tubules. -Luteinizing Hormone (LH) controls production of testosterone by the interstitial cells of testes.
     • Testosterone major sex hormone in males. Establishes and maintain secondary sex characteristics and responsible for greater muscular development in males.

5. Human female reproduction system

   • important organs and its function
     • OVARIES - produce egg and sex hormones
     • UTERUS (WOMB) - houses developing embryo and fetus
     • VAGINA - receives penis during copulation and serves as birth canal.
     • OVIDUCTS (FALLOPIAN TUBES) - conduct egg, location of fertilization
   • ovarian cycle
     • Follicle changes from a primary to a secondary vesicular (Graafian) follicle under the influence of FSH ans LH. Ovulation release ofsecondary oocyte from vesicular follice and secondary oocyte enters an oviduct. Follicle develops in corpus luteum- - degenerates if apregnancy does not occur.
     • phases of ovarian cycle. -FOLLICULAR PHASE : FSH promotes the development of a follicle. Follicle secerets estrogens. LUTEAL PHASE: LH promotes development of corpus luteum and corpus luteum secrets progesterone.
   • uterine cycle
     • Sex hormones produced in ovarian cycle affect the endometrium. A twenty eight day uterine cycle : (DAY 1-5): endometrium disintegrate. Menses pass out of the vagina during menstruation. (DAY 6-13) : endometrium thickens and ovulation usually occurs on 14th day. (DAY 15-28): endometrium double in thickness and uterine glands mature and produce a thick secretion.
   • hormonal control of ovaries
     • LH
     • FSH