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Hormonal regulation. Hormonal Regulation Endocrine glands: ductless glands ( into body – extracellular fluid ) Hormones : chem. secretions from a gland Usually transported by blood. Pituitary gland (base of the brain) Secretes 4 important hormones : gonadotropins (FSH, LH)
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Hormonal Regulation Endocrine glands: ductless glands (into body – extracellular fluid) Hormones: chem. secretions from a gland Usually transported by blood
Pituitary gland (base of the brain) Secretes 4 important hormones: gonadotropins (FSH, LH) oxytocin prolactin
Follicle Stimulating Hormone (FSH) Female: development and maturation of ovarian follicle (ovaries) Male: production, development and maturation of sperm (Testes – seminiferous tubules) Luteinising Hormone (LH) Female: stimulates secretion of oestrogen & progesterone, stimulates ovulation & formation of Corpus Luteum Male: stimulates secretion of testosterone (develop male reproductive system & develop 2nd sexual characteristics)
Oxytocin Stimulates contraction of smooth muscle in uterus (during birth) Promotes contraction of muscle cells surrounding breast lobules (during breast feeding) Prolactin (lactogenic Hormone) prepares & maintenance of milk production
Corpus Luteum Progesterone maintains endometrium, develops / maintain placenta, develop milk secreting glands Oestrogen develops female reproductive system and 2nd sexual characteristics
Placenta Human Chorionic Gonadotriopin (HCG) maintains Corpus Luteum wow.
Puberty & Secondary sexual characteristics Characteristics associated with gender but not directly involved in reproduction. Females: Enlarging of breasts Broadening of the hips (growth in pelvic bone / fat deposition) Male: Facial / body hair Increase in larynx size (deeper voice) Both Pubic hair (straight/light dark, thicker, curlier) Armpit hair
Sexual Intercourse Sexual Intercourse (coitus) Erection: enlarged and firm penis (blood fills erectile tissue) May result from visual, psychological or physical stimuli Ejaculation: rhythmic contractions of the epididymis, vas deferens, seminal vesicles & prostate gland. Results in rapid heartbeat, increased blood pressure / breathing rate & pleasurable sensation (orgasm) Approx3mL semen, 250 -300 million sperm
Sexual Intercourse Women are aroused less by association & more by direct contract. Female clitoris may also swell with blood Increase secretions of mucus Female orgasm / climax
Fertilisation sperm travels from epididymis, vas deferens to urethra. Semen exits penis into vagina (insemination) Sperm travels through cervix / uterus, and up uterine tubes (minutes) Movements aided by muscular contractions (uterus) Approx1000 – 2000 sperm reach uterine tubes Egg is 1/3 way down fallopian tubes, meets sperm (fertilisation) Egg movement aided by beating cilia and uterine tube contractions Mature egg is surrounded by follicle cells (Corona radiata) Cells held together by an acid (enzyme in sperm breaks down acid) Not enough enzyme in one sperm, many must assist Upon entrance of one sperm, egg makes a membrane stopping others entering
Fertilisation Once sperm is in, tail is absorbed and head moves through cytoplasm. (head = male pronucleus) Stimulates second meiotic division Ends in female pronucleus Male + female pronucleus = zygote Egg can be fertilised up to 24 hrs after ovulation (min 12 hrs later) Sperm can be fertilised up to 72 hrs after ejaculation No earlier than 60 hrs before ovulation and 24 hrs after. 84 hr window
Impotence / infertility Impotence: Can’t achieve / maintain an erection physical abnormalities, blood vessel / nervous system disorder, psychological & emotional problems Infertility: Inability to fertilise an ovum can be caused by malnutrition, radiation, diseases, physical abnormalities Decreased male fertility due to exposure to endocrine disruptors which mimic oestrogen.