BIOL 1140 1st Edition Lecture 26Outline of Last LectureI. Functions of the Skeletal SystemII. 3 Types of Connective TissueIII. Structure of BoneIV. What Holds Bones Together?V. Cartilage is Found on Ends of BoneVI. Calcium HomeostasisVII. Bone Plasticity and RepairOutline of Current LectureI. Function of the Reproductive SystemsII. The Male Reproductive SystemIII. Make Reproductive Anatomy IV. The Hypothalamus and Pituitary GlandV. Male Hormonal Control of ReproductionVI. The Female Reproductive SystemVII. Female Reproductive AnatomyVIII. Female Hormonal Control of ReproductionIX. Estrogen and ProgesteroneCurrent Lecture I. Function of the Reproductive Systemsa. Both male and female reproductive systems have the goal of joining sperm and egg in an enviornment that can support development of a new invididualII. The Male Reproductive Systema. The purpose of the male reproductive system is to produce sperm that can fertilize an egg, and to deliver that sperm to the eggb. Not cyclical; sperm and hormones are produced and maintained at homeostasisc. Process is under hormonal controli. Negative feedbackIII. Male Reproductive Anatomya. Immature sperm are produced in sets of tubules in the two male testesi. Testes are found outside the body cavity in a muscular sac called the scrotum1. Keeps temperature cooler for proper sperm developmentii. Testes contain seminiferous tubules, where the sperm developThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.1. Tubules are about 23 feet longiii. Sertoli cells nourish spermiv. Leydig cells surround the seminiferous tubules and produce testosteroneb. Sperm are derived from spermatogoniai. Reproductive stem cells found at the periphery of the seminiferous tubulesii. Divide by mitosis to form 2 types of cells1. Another spermatogoniaa. Allow males to keep producing sperm throughout their lives2. Primary spermatocytea. Develops into sperm by meiosisi. Primary spermatocyte divides once to produce 2 secondary spermatocytesii. Secondary spermatocytes divide again to produce 4 immature spermatidsc. Sperm are transported to the epididymis, for further development and storaged. Upon orgasm and ejaculation, sperm are transported through the vas deferens to the urethra, which leads out of the bodyi. Secretions from accessory glands are added to the sperm to form semen1. Seminal vesicles, bulbourethral gonad, and prostate gland make 95% of semen2. Provide nutrients, lubrication, and neutralize the acidic environment of the vagina IV. The Hypothalamus and Pituitary Glanda. The hypothalamus secretes releasing hormones that stimulate the anterior pituitary gland to release tropic hormones, which in turn stimulate another gland to release its hormonesi. Hypothalamus -> GnRHii. Anterior Pituitary -> FSH and LHiii. Gonads -> hormones that assist reproduction and feedback to the brainV. Male Hormonal Control of Reproductiona. Anterior Pituitary Gland secretes:i. FSH = follicle stimulating hormone1. Promotes sperm productive in seminiferous tubulesii. LS = Luteinizing Hormone1. Stimulates testosterone interstitial cellsb. Leydig cells secrete:i. Testosterone1. Causes male sexual development2. Causes secondary sexual characteristicsc. Testosterone feeds back to pituitary glandi. If levels of testosterone are sensed as too high by brain, GnRH, RSH, and LH production stopsii. If levels of testosterone are sensed as too low, GnRH, RSH, and LH production increasesd. This negative feedback mechanism assures that testosterone and sperm production remain constantVI. The Female Reproductive Systema. The female reproductive system must fulfil two different rolesi. Formation of an eggii. Creation of an environment in which a fertilize egg can developb. Females maintain an approx. 28-day cycle during which both of these events occuri. Cycle is maintained by hormones1. Negative and positive feedbackVII. Female Reproductive Anatomya. Ovaries: pair of female gonads that contain eggs; an egg is contained in a follicle made of cells that nourish and protect the eggi. Approximately 250,000follicles at pubertyb. Uterus: the womb; provides a safe nutritive environment where a baby develops for 9 monthsi. Lining is called the endometriumii. Surrounded by a layer of smooth muscle called the myometrium c. Fallopian tubes: passageway from ovary to uterusi. Lined with cilia to propel the eggii. Also use peristalsisiii. Ovulation = when an oocyte bursts out of the ovary to enter the fallopian tube; occurs approx. once every 28 days1. Fimbriae (fringes) on the ends of fallopian tubes sweep ovulated egg insideiv. Fertilization will occur here If sperm are presentd. Vagina: the passageway to outside of the body; sperm can enter here, and a baby will exit here during childbirthi. The opening at the bottom of the uterus is called the cervix; it opens into the vaginaVIII. Female Hormonal Control of Reproductiona. Females have a 28 day cycle during which an egg reaches maturity and Is ovulated, and the endometrium is prepared for implantation of an embryob. Ovarian cycle:i. Maturation of an ovarian follicle, ovulation, and development of corpus luteum1. Under control of hormones FSH and LH produced by the Anterior Pituitary Glanda. FSH = Follicle stimulating hormone; promotes maturation of an ovarian follicleb. LH = luteinizing hormone; triggers ovulation and promotes development of corpus luteum c. Uterine Cycle: changes in thickness of the endometrium layer of the uterusi. Days 1-5 Menstruationii. Days 6-13 Proliferative phase; endometrium begins to thicken1. Stimulated by estrogen made by secondary follicleiii. Day 14 - Ovulationiv. Days 15-28 Secondary Phase; endometrium thickens further and develops glandular tissue1. Stimulated by estrogen and progesterone made by corpus luteumd. Pituitary gland produces FSH and LH to stimulate the ovarian cycle in the ovarye. In turn, structures in the ovary then produce estrogen that feeds back to the hypothalamus/pituitary i. This feedback is positive feedback it stimulates the brain to produce more hormonesf. Once the corpus luteum forms after ovulation, it produces progesteroneg. Progesterone feeds back to hypothalamus/pituitaryi. This feedback is negative - causes the brain to stop producing LH and FSH1. Prevents additional follicle maturation and ovulation until cycle is completeh. If NO pregnancy occurs:i. About 12 days after formation of