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Chapter 25

Chapter 25. Reproduction and Development in Humans. (I) Female Reproductive. System. Terms. Gametogenesis. The production of gametes (sex cells) Males = spermatogenesis in the testes Females = oogenesis in the ovaries. (A) Ovaries. The female gonads

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Chapter 25

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  1. Chapter 25 Reproduction and Development in Humans

  2. (I) Female Reproductive System

  3. Terms

  4. Gametogenesis • The production of gametes (sex cells) • Males = spermatogenesis in the testes • Females = oogenesis in the ovaries

  5. (A) Ovaries • The female gonads • Located within the lower portion of the body cavity • In the ovaries, each egg cell (ovum) is present in a tiny sac called a follicle

  6. (A) Ovaries 3. About once a month, a follicle matures and bursts. The egg is then released and travels into the oviduct (Fallopian tubules) ****This is known as ovulation

  7. 4. Fertilization takes place within the Fallopian tubules (oviduct) forming a zygote 5. The zygote then travels down and into the uterus where it implants into the uterine lining and develops 6. When embryonic development of the baby is completed, the cervix dilates (opens) and the baby travels through the birth canal known as the vagina

  8. 7. The ovaries also produce sex hormones known as estrogen and progesterone a) estrogen- used for the development of secondary sex characteristics like mammary glands (breasts) b) progesterone- maintains pregnancy

  9. Figure 39–14 The Female Reproductive System Section 39-3

  10. The Arethra: • Oops, wrong one

  11. Ovary

  12. Female Reproductive Structures, (side VW) Vertebrae Bladder Rectum Sperms path

  13. Figure 39–2 The Endocrine Glands Section 39-1 Pineal gland The pineal gland releases melatonin, which is involved in rhythmic activities, such as daily sleep-wake cycles. Hypothalamus The hypothalamus makes hormones that control the pituitary gland. In addition, it makes hormones that are stored in the pituitary gland. Thyroid The thyroid produces thyroxine, which regulates metabolism. Pituitary gland The pituitary gland produces hormones that regulate many of the other endocrine glands. Pancreas The pancreas produces insulin and glucagon, which regulate the level of glucose in the blood. Parathyroid glands These four glands release parathyroid hormone, which regulate the level of calcium in the blood. Ovary The ovaries produce estrogen and progesterone. Estrogen is required for the development of secondary sex characteristics and for the development of eggs. Progesterone prepares the uterus for a fertilized egg. Thymus During childhood, the thymus releases thymosin, which stimulates Tcell development. Testis The testes produce testosterone, which is responsible for sperm production and the development of male secondary sex characteristics Adrenal glands The adrenal glands release epinephrine and nonepinephrine, which help the body deal with stress.

  14. The Effects of Estrogen Section 39-3

  15. Figure 39–22 The Placenta Section 39-4

  16. (II) Menstrual Cycle • Mature egg develops and is released • Begins at puberty and ends at menopause • Hormones involved: FSH estrogen LH progesterone • Stages involved in order: follicle stage  ovulation  corpus luteum  menstruation

  17. 1. Follicle Stage 10-14 days * FSH is secreted by the pituitary gland which stimulates maturation of egg in the follicle ** As the follicle develops, it releases estrogen which stimulates the uterine lining to thicken with blood 2. Ovulation Secretion of LH (lutenizing hormone) from the pituitary causes a mature egg to be released from the follicle and into the fallopian tubules (oviduct) 3. Corpus Luteum 10-12 days * The burst follicle fills with cells forming the corpus luteum, which produces progesterone fuher thickening of the uterine lining 4. Menstruation 3-5 days If the egg is not fertilized, progesterone secretion decreases and the lining of the uterus breaks down The lining of the uterus is sloughed off and discharged from the body through the vagina as a result (period).

  18. The Menstrual Cycle Section 39-3

  19. The Menstrual Cycle Section 39-3

  20. Do Now 4/26 • Describe the menstrual cycle. (remember there are 4 stage!!!!) • What is a Feedback Mechanism?

  21. (II) Menstrual Cycle

  22. 1. Follicle Stage • 10-14 days • FSH is secreted by the pituitary gland which stimulates maturation of egg in the follicle • As the follicle develops, it releases estrogen which stimulates the uterine lining to thicken with blood

  23. 2. Ovulation • Secretion of LH (lutenizing hormone) from the pituitary causes a mature egg to be released from the follicle and into the fallopian tubules (oviduct)

  24. 3. Corpus Luteum Stage • 10-12 days • The burst follicle fills with cells forming the corpus luteum, which produces progesterone • Progesterone stimulates further thickening of the uterine lining

  25. 4. Menstruation • 3-5 days • If the egg is not fertilized, progesterone secretion decreases and the lining of the uterus breaks down • The lining of the uterus is sloughed off and discharged from the body through the vagina as a result (period).

  26. Check your hw answers using the transparency. Do Now 4/29:

  27. (VI) Male Reproductive System

  28. Figure 39–12 The Male Reproductive System Section 39-3

  29. (A) Testes • Are the male gonads • Produce sperm • Sperm is produced in the seminiferous tubules and stored in the epididymis • Sperm then leaves the epididymis through the vas deferens and into the urethra (which is a tube inside the penis)

  30. The process • The penis is a structural adaptation for internal fertilization • Glands secrete a liquid into the urethra which combines with the sperm cells. This liquid serves as a transport medium for the sperm cells and is called semen • Testes also produce the male sex hormone called testosterone

  31. Testosterone regulates the maturation of sperm and the development of secondary sex characteristics such as beard development and voice pitch Scrotum- sac in which the testes are located a) outside the body b) keeps the temperature 1-2 degrees Celsius cooler than normal body temperature c) this provides an optimum temperature for sperm production

  32. HEAD with NUCLEUS & ACROSPORE Shaft (middle region) TAIL (MOTILITY)

  33. Male sterilization or vasectomy is a simple procedure in which a piece of each vas deferens is cut out just above the epididymis and the cut ends are tied. This procedure is normally done under local anesthetic in the doctor's office. Because the sperm stored in the epididymis can no longer flow through the vas deferens, the man's ejaculate does not contain sperm. Vasectomy

  34. (III) Fertilization and Implantation • Fertilization occurs in the fallopian tubules (oviduct) • If the egg is not fertilized within 24 hours after ovulation, it will deteriorate • After fertilization, the zygote undergoes cleavage and becomes an embryo

  35. (I) Sexual Reproduction • Two parents give rise to new offspring by the fusion of nuclear materials from two different cells • Offspring are not identical to the parent • Variations exist, which increases the species ability to adapt to the changing environment

  36. (A) Reproductive System • Gonads- specialized organs that produce gametes a) ovaries - female gonad - produce ova (egg) b) testes - male gonad - produce sperm cell

  37. (B) Hermaphrodite • Contain both male and female reproductive structures

  38. (C) Gametogenesis • Process by which gametes are produced in the gonads • Two types: -Spermatogenesis - Oogenesis

  39. Oogenesis • The primary oocyte goes through first meiotic division and the cytoplasm of the cell is divided unequally • The larger daughter cell is called the secondary oocyte and the smaller daughter cell is called the polar body • During second meiotic division, 1 mature ovum is produced and 3 polar bodies

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