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Download Sperm Release Pathway: The Parasympathetic Step
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Sperm Release Pathway: The Parasympathetic Step 1. Brain perceives sexual stimulus 2. NO (nitrous oxide) released in smooth muscle lining arterioles of erectile tissue 3. Arterial muscles relax, arterioles dilate 4. Arterioles fill with blood 5. Engorged arterioles compress venules 6. Blood is trapped in erectile tissue arterioles. Erection achieved. Sperm Release Pathway: The Sympathetic Step 7. Prolonged sexual stimulus results in spinal reflex impulse… 8. Causes contraction of: *vas deferens *bulbourethral gland *prostate gland * seminal vesicles 9. Semen empties into urethra 10. Urethral sphincter muscles contract 11. Semen forcefully ejected from urethra Ejaculation Female Reproductive System I. Female Reproductive Structures Ovaries Oviducts Uterus Cervix Vagina Brain A. Ovaries Primary Reproductive Organ/Female Gonad Paired Attached medially to uterus by ovarian ligament Filled with ovarian follicles Each ovarian follicle contains an immature oocyte (gamete) Follicle membrane Immature oocyte OVARIAN FOLLICLE Onset of Puberty Hypothalamus released GnRH (Gonadotropin Releasing Hormone) Pituitary Gland releases: FSH LH ESTROGEN RELEASE Release of Estrogen at onset of Puberty… SECONDARY SEX CHARACTERISTICS Breast development Widening of pelvic girdle Body hair MENARCHE First ovulation followed by menstrual period The Ovarian Cycle Results in the release of: gamete hormones required for pregnancy Repeats ~ 28 days OVULATION: major event of Ovarian Cycle! release of mature oocyte from ovary 3 Phases of Ovarian Cycle Follicular Phase 2. Ovulation 3. Luteal Phase 1. 1. Follicular Phase Days 1 - 14 Granulosa cells (Epithelium/CT) of follicle provide nutrition/support/protection to oocyte Follicle increases in size around oocyte Follicle secretes Estrogen hormone Zona pellucida forms around oocyte Thick protective, nutritive membrane Increased granulosa cells surround oocyte “Corona radiata” nucleus Corona Radiata Zona pellucida 2. Ovulation Day • Day 14 Wall of ovary bulges and bursts • Oocyte (w/ corona radiata) expelled from ovary! Ovulation Identify: Ovary Follicle Oocyte Corona Radiata 3. Luteal Phase Days 15 – 28 Follicle remains in ovary after ovulation Granulosa cells secrete hormones: Progesterone Estrogen Follicle has been transformed into… CORPUS LUTEUM! The fate of the Corpus Luteum… If sperm are present and oocyte becomes fertilized… Corpus Luteum continues production of progesterone (pregnancy hormone) for 1st three months of pregnancy! If fertilization of oocyte does NOT occur… Corpus luteum stops hormone production and breaks down B. It Starts with the Brain… C. Fallopian Tubes Aka: oviducts / uterine tubes Attached medially to uterus Lateral region surrounding ovary… Ampulla : common site of fertilization Possesses ciliated finger-like projections that hang over ovary… Fimbriae ! Ampulla Fimbriae D. The Uterus “womb” Thick muscular lining Resembles a pear in shape and size Functions to receive, retain, and nourish the fertilized ovum The Uterus is… Divided into regions Fundus: Body: Cervix: rounded superior region largest region narrow inferior region Fundus Body Cervix The Uterus is… Composed of three layers: Perimetrium: Myometrium: Endometrium: outer visceral layer middle muscular thickest layer inner epithelial layer site of implantation of fertilized ovum The Uterus is… Highly vascular! Uterine Arteries: branch to provide blood to myometrial and endometrial layers of uterus! The Vagina Extends from cervix to external environment Functions to: Allow for passage of infant (“birth canal”) Allow for passage of menstrual flow Receive penis during intercourse (female organ of copulation) Acidic pH in adults protection against infection hostile environment for sperm The fate of the Ovum... Post-Ovulation Menstruation Occurs ~ 14 days post ovulation Occurs ONLY if fertilization of ovum does NOT occur Endometrium layer of uterus is shed Results in bleeding from vagina for ~3-5 days Endometrial layer will immediately begin rebuilding vascular tissue during days 1-14 of Ovarian Cycle (due to estrogen!)
