Presentation is loading. Please wait.

Presentation is loading. Please wait.

Chapter 25 Reproduction and Development in Humans.

Similar presentations


Presentation on theme: "Chapter 25 Reproduction and Development in Humans."— Presentation transcript:

1

2 Chapter 25 Reproduction and Development in Humans

3 (I) Female Reproductive System

4

5 Terms GonadsGametesGametogenesis (The process) FemalesOvariesOvaOogenesis MalesTestesSpermSpermatogenesis

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

7 (A) Ovaries The female gonads 1. Located within the lower portion of the body cavity 2. In the ovaries, each egg cell (ovum) is present in a tiny sac called a follicle

8 (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

9 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

10 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

11 Figure 39–14The Female Reproductive System Section 39-3

12 Oops, wrong one The Arethra:

13

14

15 Ovary

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

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

18 The Effects of Estrogen Section 39-3

19 Figure 39–22 The Placenta Section 39-4

20 (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

21 1. Follicle Stage 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. OvulationSecretion 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 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).

22 The Menstrual Cycle Section 39-3

23 The Menstrual Cycle Section 39-3

24 Do Now 4/26 1. Describe the menstrual cycle. (remember there are 4 stage!!!!) 2. What is a Feedback Mechanism?

25 (II) Menstrual Cycle

26 1. Follicle Stage 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

27 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)

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

29

30 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).

31

32

33 Check your hw answers using the transparency.

34 (VI) Male Reproductive System

35 Figure 39–12The Male Reproductive System Section 39-3

36 (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)

37 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

38 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

39

40

41

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

43

44

45 Vasectomy 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.

46 (III) Fertilization and Implantation 1. Fertilization occurs in the fallopian tubules (oviduct) 2. If the egg is not fertilized within 24 hours after ovulation, it will deteriorate 3. After fertilization, the zygote undergoes cleavage and becomes an embryo

47 (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

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

49 (B) Hermaphrodite Contain both male and female reproductive structures

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

51 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

52 Spermatogenesis Primary spermatocyte goes through first meiotic division and form two daughter cells of equal size Each daughter cell (secondary spermatocyte) goes through the second meiotic division forming four motile sperm cells of equal size

53

54 Comparison of Ova and Sperm Egg cells contain stored food in the form of yolk Egg cells are larger than sperm Sperm are motile, egg cells are not

55 (B) Fertilization The fusion of the nuclei of one sperm with one ova (egg) to produce a zygote Sperm (n) + Ovum (n) =2n Sperm (23) + Ovum (23) = 46

56 Parthenogenesis An embryo develops from an unfertilized egg typically involves the development of eggs into viable offspring from females without fertilization by sperm.. Parthenogenesis is no longer only for lower invertebrates, such as aphids, mites and nematode worms--it's also been found in fish, bees, birds and lizards. the second polar body -- the daughter cell produced along with the egg in the second stage of meiosis -- acts like a sperm and re-enters the egg. Essentially the egg fertilizes itself! As this polar body contains identical genetic material to the egg, having been produced by normal division of an already haploid cell, the resulting diploid cell has only half the genetic diversity of the female's original cells. Thus fewer bands appear in the DNA fingerprint of the offspring.

57 Parthenogenesis

58 Fertilization Union of a haploid sperm nucleus with a haploid egg nucleus This results in a diploid zygote with the full number of chromosomes n n 2n

59 Fertilization Union of a haploid sperm nucleus with a haploid egg nucleus This results in a diploid zygote with the full number of chromosomes

60 Fertilization and the Stages of Mitosis

61 Two types of Fertilization External Fertilization Internal Fertilization **Parthenogenesis**

62 Eggs are fertilized outside the body of the femaleEggs are fertilized outside the body of the female Large number of eggs are requiredLarge number of eggs are required This type of fertilization is found in an aquatic environmentThis type of fertilization is found in an aquatic environment Ex: fish and frogs Ex: fish and frogs External Fertilization

63 Spawning???

64 External Fertilization

65

66

67

68 What are some differences between External and Internal Fertilization? Provide examples!!!

69 External Fertilization

70

71

72

73 Internal Fertilization Takes place inside the body of the female Less eggs are required Ex: mammals, birds and reptiles

74 Internal Fertilization

75 The embryo arrives in the uterus 5-10 days after fertilization The embryo implants into the uterine wall and establishes pregnancy Placenta- nourishes the embryo Umbilical cord- attaches the embryo to the placenta Amnion- embryo develops inside the amniotic sac which contains amniotic fluid that serves as a shock absorber Gestation Period- length of pregnancy (approximately nine months)

76 Fertilization

77 Good Review Webpage

78 Implantation of blastocyst Day 7 Fertilization Day 4 Day 3 Day 2 Day 1 Day 0 Egg released by ovary Fertilization and Implantation Section 39-4 Uterine wall Blastocyst Morula 4 cells2 cells Zygote Ovary Fallopian tube

79 Development The zygote, which is a fertilized egg consisting of one cell, will begin to divide rapidly by mitosis forming the early developing human embryo. Fertilization and the initial stages of this mitotic cell division occur in the oviduct. The early embryo is migrates down the fallopian tube and completes most of its development in the wall of the uterus.

80 Do Now Looking at the diagram above. Hypothesize the systems that will develop from these three layers. Reproductive Muscles, Skeleton Digestive Nervous ETC Ectoderm Mesoderm Endoderm

81 It is the three germ layers that give rise to all the tissues and organs of an animal EctodermMesodermEndoderm Nervous system Digestive System lining of mouth, nostrils, and anus epidermis of skin, sweat glands, hair, and nails bones and muscles blood and blood vessels reproductive and excretory system dermis layer of skin lining of digestive tract lining of trachea, bronchi, and lungs liver, pancreas thyroid, parathyroid urinary bladder

82 The Three germ layers

83 Do Now Identify what is the purpose of the following: The placenta: The umbilical cord:. The amniotic fluid:

84 Do Now answers The placenta is a combination of maternal and fetal tissue which allows for the exchange of materials with the fetus and mother. Needed materials such as food and oxygen diffuse through the placenta to the fetus, while wastes from the fetus diffuse to the mother. The umbilical cord is a fetal structure containing blood vessels which allows materials to be carried between the fetus and placenta in both directions. The amniotic fluid surrounds the fetus and helps to provide a shock absorber to protect the fetus against mechanical injury in the event the mother is shaken or injured in some manner.

85 Human Development

86 Fetal Development Development is a highly regulated process After this small cluster of cells called the gastrula forms in humans, tissues begin to form. In humans, the embryonic development of essential organs occurs in early stages of pregnancy. During the first three months of human development, organs begin to form. The human embryo is usually referred to as a fetus when human like features become visible in its structure. All organs and body features are developed by the end of the sixth month. During the last three months of pregnancy, organs and features develop well enough to function after birth.

87 What are some things that could affect fetal development? 6 weeks 4 months

88 What are some things that could affect fetal development? The embryo (or fetus) may encounter risks from faults in its genes and from its mother's exposure to environmental factors such as: inadequate diet use of alcohol (Fetal alcohol syndrome) Tobacco Drugs other toxins infections

89 Reproductive Technologies Reproductive technology has medical, agricultural, and ecological applications. In many instances, these technologies have progressed at a faster rate than the ethical considerations resulting from these technologies. Some of these techniques include birth control methods used to block the process of fertilization. Many technologies now exist to enhance the process of fertilization and development in humans and other organisms. Amniocentesis Hormone therapy can cause increased egg production. Surgery can open blocked fallopian tubes in females and the vas deferens in males. In vitro fertilization (test-tube babies) is a widely used technique to aid infertile couples, allowing them to have children where this otherwise would not be possible.

90 Amniocentesis Fetal cells are removed and surveyed for genetic disorders

91 Reproductive Technologies

92

93 (IV) Multiple Births 1. Identical twins- Develops from one zygote separating into two during cleavage. One sperm and one egg is involved and therefore the babies will look identical and must be of same sex

94 (IV) Multiple Births 1. Identical twins- Develops from one zygote separating into two during cleavage. One sperm and one egg is involved and therefore the babies will look identical and must be of same sex

95 Identical twins do not have identical fingerprints. They are a product of their environment.

96

97 Conjoined Twins

98 Conjoined “Siamese” Twins Chang and Eng

99 Eng Bunker---Chang Bunker Born: May 11, 1811 Died: January 11, 1874

100 The developing embryo begins to split into identical twins but then stops part way leaving the partially separated egg to mature into a conjoined fetus.

101 They are more often female than male (ratio of 3:1)

102 They occur as often as once in every 40,000 births but only once in every 200,000 live births.

103 40% are still born 70% are female - even though monozygotic twins are more frequently male than female. 75% are still born or die within 24 hours.

104 Cephalophagus

105 Dicephalus This refers to one body with two heads.

106 Ischophagus Anterior union of the lower half of the body

107

108 Conjoined twins Parasitic twins: Asymmetrical conjoined twins, one twin being small, less formed, and dependent upon the other. Fetus in fetu: Situation in which an imperfect fetus is contained completely within the body of its sibling.

109 (V) Multiple Births Fraternal twins- Develop from two separate eggs, each fertilized by separate sperm cells. Therefore, the babies may not look identical and could be of different sex. Simply ciblings!

110 (V) Multiple Births Fertility drugs often cause production of more than one ovum during ovulation. Septuplets = 7 ova + 7 sperm (7 zygotes)

111 (V) Multiple Births


Download ppt "Chapter 25 Reproduction and Development in Humans."

Similar presentations


Ads by Google