4Male reproductive System Essentially 4 parts:TestesGonads, in scrotum; make gamates and releases sex hormonesDuctsEpididymis, sperm ductsGlandsSeminal vesicles, prostate glandPenisUrethra and erectile tissue. Arousal leads to filling of the tissue with blood erection. Enables it to function as a penetrating organ in intercourse
5Male Reproductive System Name the structures that are unique to the male reproductive system.
6Male Reproductive System (cont.) Sperm cellsHeadNucleus with 23 chromosomesAcrosome – enzyme-filled sacHelps sperm penetrate ovumMidpieceMitochrondria that generate cell’s energyTailFlagellum that propels sperm forward
7Male Reproductive System: Erection, Orgasm, and Ejaculation Parasympathetic nervous system stimulates erectile tissueBecome engorged with bloodOrgasmSperm cells propelled out of testes into urethraSecretions from accessory organs also released into urethraEjaculationSemen is forced out of urethraSympathetic nerves then stimulate erectile tissue to release bloodPenis returns to flaccid state
9Female reproductive System I Function is to:Produce gamates (ova)Receive the male gamatesProvide a suitable environment for:fertilisationDevelopment of fetusProvide a means of expelling the developed fetus during parturition (birth)
10Female reproductive System II Consists of:OvariesProduce Ova, secrete progesterone + oestrogenOviducts (Fallopian Tubes)UterusHollow, pearshaped, muscular. Lining – endometrium – undergoes cyclical changes. Cervix part of uterus that projects thru’ from vaginaVaginaMuscular tube adapted for reception of the penis and passage of baby out during birth.
11Female Reproductive System Name the structures that are unique to the female reproductive system.
14Production of Gametes Production of Gametes – Gametogenesis Involves special cell division – meiosisSpermatogenesisOogenesis
15Spermatogenesis 1 Each testis is packed with seminiferous tubules In these Spermatogenesis takes placeSpermatogonia (germ cells) line the tubules dividing my mitosis to give more spermatogonia (Type A and Type B)
16Spermatogenesis 2Type B Spermatogonia will undergo meiosis to eventually form spermatozoaType B also known as primary spermatocytesAfter the first meiotic division they become secondary spermatocytes
17Spermatogenesis 3Secondary spermatocytes rapidly under go the second meiotic division to form spermatidsSpermatids undergo development into spermatozoa
21Spermatogenesis 6 Testes controlled by the anterior pituitary gland Follicle stimulating hormone (FSH)Interstitial Cell Stimulating Hormone (ICSH)ICSH stimulates leydig cells to secrete testosterone inhibits FSH and ICSH secretion. Negative feedback.
22Oogenesis 1 The process primordial germ cells (oogonia) become ova Begins in fetus – oogonia divide by mitosisBy 4 or 5months, some are enlarged – potential to become gametesNow called primary oocyte
23Oogenesis 2 Primary oocytes begin first stage of meiosis By month 7 they are surrounded by follicular cells to form primary folliclesThen Meiosis stops until puberty
24Oogenesis 3 Once a month some of the primary oocytes continue meiosis move to surface of ovaryOne reaches maturity, others degenerateFirst meiotic division finishes – secondary oocyteOvulation follicle ruptures, oocyte released (once released called ovum)2nd Meiotic division doesn’t occur until the head of a spermatozoan enters the ovum
26Oogenesis 5After ovulation, the ruptured follicle fills with a blood clotCells enlarge temporary endocrine structure, the corpus luteumGrows for 7 – 8 days secreting progesterone and oestrogenIf fertilisation/implantation don’t occur, corpus luteum degenerates after 12 – 14 days.
29Pregnancy: Fertilisation Pregnancy – condition of having a developing offspring in the uterusFertilisation – process in which a sperm cell unites with an ovum; results in pregnancyOnly one sperm cell penetrates the follicular cells and the zona pellucida that surround the ovum’s cell membrane
31Zygote forms from union of ovum and sperm After fertilization, ovum releases enzymes that cause the zona pellucida to become impenetrable to other spermZygote forms from union of ovum and spermContains 46 chromosomes
33Pregnancy: The Prenatal Period Time before birthZygote – undergoes rapid mitosisFirst week after fertilizationCleavage – rapid cell divisionMorula – ball of cells resulting from cleavageTravels down fallopian tube to uterusBecomes blastocyst which implants in endometrial wallBlastocystSome cells (inner cell mass) become embryoOthers, along with cells from uterus, form placenta
34Fertilisation & Implantation (brief) Sperm motile – 1mm/minWith muscular movements of uterus get through cervix into oviductsFertilisation takes place (diploid)Fertilised ovum – zygote – begins mitosis3 days – morula – 16 cells, enters uterusFluid enters morula, cells rearrange to become hollow – blastocystBlastocyst implants into endometrium – total 10 days
35Pregnancy: Hormonal Changes Embryonic cells secrete human chorionic gonadotropin (HCG)Maintains the corpus luteumEstrogen and progesteroneSecreted by corpus luteum and placentaFunctionsStimulate uterine lining to thicken, development of mammary glands, enlargement of female reproductive organsInhibit release of FSH and LH from anterior pituitary gland (preventing ovulation) and uterine contractions
36Pregnancy Testing Kits These use monoclonal antibodies to test for hormone hCGhCG produced by placentaThe test relies on the reaction between hCG and antibodies bound to coloured latex beads