Reproductive System- Part 1 PDF

Reproductive System- Part 1 Nermin Eissa, Ph.D. College of Health Sciences Abu Dhabi University Fall-2023  Human Life Cycle 1 Learning Outcomes: Describe the human life cycle and explain the role of mitosis a...

Reproductive System- Part 1 Nermin Eissa, Ph.D. College of Health Sciences Abu Dhabi University Fall-2023  Human Life Cycle 1 Learning Outcomes: Describe the human life cycle and explain the role of mitosis and meiosis in this cycle. Describe functions for each male and female reproductive system organ. Describe the location and stages of spermatogenesis. Summarize how hormones regulate the male reproductive system. 2 ©2020 McGraw-Hill Education  Human Life Cycle 2 Reproductive system—produces gametes (eggs, sperm). Females also protect and nourish the developing fetus until birth. 3 ©2020 McGraw-Hill Education  Functions of the Reproductive Organs 1 The reproductive organs, or genitals, have the following functions: Males produce sperm within testes, and females produce eggs within ovaries. Males transport sperm in ducts; females transport eggs in uterine tubes to the uterus. The uterus allows the fertilized egg to develop within the body. After birth, the breast provides nourishment. The testes and ovaries produce sex hormones. Bring about masculinization or feminization. 4 ©2020 McGraw-Hill Education  Puberty The time period during which a child becomes a sexually competent adult. Sexual maturity typically occurs between the ages of 10 and 14 in girls and 12 and 16 in boys. At the completion of puberty, the individual is capable of producing children. 5 ©2020 McGraw-Hill Education  Mitosis and Meiosis 1 DNA (Deoxyribonucleic acid)—genetic instructions. Distributed among 46 chromosomes within the nucleus of most body cells. 23 pairs; each pair contains one from both parents. 6 ©2020 McGraw-Hill Education  Mitosis and Meiosis 2 During most of the life cycle, cells divide by mitosis. Mitosis is duplication division; each of the cells that exit mitosis has the same 46 chromosomes. Cells produce exact copies of themselves. Mitosis is used for growth and repair of damaged tissues. 7 ©2020 McGraw-Hill Education  Mitosis and Meiosis 3 Meiosis—cell division for the purposes of reproduction. Takes place only in the testes (during sperm production) and ovaries (during egg production). 8 ©2020 McGraw-Hill Education  More Mitosis and Meiosis 1 Is also called reduction division. Chromosome number is reduced from 46 (diploid or 2n) to 23 (haploid or n). Requires two successive divisions, called meiosis I and meiosis II. Introduces genetic variation. 9 ©2020 McGraw-Hill Education  More Mitosis and Meiosis 2 Following meiosis, the haploid cells develop into either sperm (males) or eggs (females). Sperm are much smaller than eggs. Zygote—formed by fusing the egg and sperm. Because they each have 23 chromosomes, the zygote has 46. 10 ©2020 McGraw-Hill Education  Check Your Progress Compare the functions of the reproductive system in males and females. Contrast the two types of cell division in the human life cycle. Explain the location of meiosis in males and females. 11 ©2020 McGraw-Hill Education  Male Reproductive Organs Male Reproductive Organs. Organ Function Testes Produce sperm and sex hormones Ducts where sperm mature and some Epididymides sperm are stored Vasa deferentia Conduct and store sperm Seminal vesicles Contribute nutrients to seminal fluid. Prostate gland Secrets fluid that nourishes and protects sperm Urethra Conducts sperm 12 ©2020 McGraw-Hill Education  Semen Semen (seminal fluid). Slightly basic pH (about 7.5). Contains the sugar fructose, which serves as an energy source. Contains prostaglandins, which cause the uterus to contract to propel the sperm toward the egg. 13 ©2020 McGraw-Hill Education  Seminiferous Tubules 1 Seminiferous tubules. Testes have compartments called lobules, each of which contains seminiferous tubules. Spermatogenesis—the production of sperm; occurs in the seminiferous tubules. Spermatogonia divide to produce primary spermatocytes (2n), which undergo meiosis I to produce secondary spermatocytes (n). These undergo meiosis II to produce four spermatids (also n, or 23 chromosomes). 14 ©2020 McGraw-Hill Education  Spermatogenesis Produces Sperm Cells Access the text alternative for these images 15 ©2020 McGraw-Hill Education  Seminiferous Tubules 2 Spermatogenesis, continued. Spermatids then develop into sperm. Sertoli cells—support, nourish, and regulate the process of spermatogenesis. Takes 74 days for development from spermatogonia to sperm. CHECK POINT 32 ©2020 McGraw-Hill Education  Spermatogenesis Produces Sperm Cells Access the text alternative for these images 33 ©2020 McGraw-Hill Education  Seminiferous Tubules 3 Spermatogenesis, concluded. Sperm (spermatozoa)—have three parts: head, middle piece, and tail. Mitochondria in the middle piece provide energy for the movement of the tail, which is a flagellum. The head contains a nucleus covered by the acrosome, which contains enzymes needed to penetrate the egg. 18 ©2020 McGraw-Hill Education  Spermatogenesis Produces Sperm Cells 19 ©2020 McGraw-Hill Education  Interstitial Cells Interstitial Cells. Produce the male sex hormones (androgens). The most important of the androgens is testosterone. Lie between the seminiferous tubules. 20 ©2020 McGraw-Hill Education  Hormonal Regulation in Males 1 Hypothalamus secretes gonadotropin-releasing hormone (GnRH), which stimulates the secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). In males, FSH promotes the production of sperm. LH stimulates the production of testosterone. Controlled by negative feedback; this maintains the fairly constant production of sperm and testosterone. 21 ©2020 McGraw-Hill Education  The Hormones that Control the Production of Sperm and Testosterone by the Testes Access the text alternative for these images 22 ©2020 McGraw-Hill Education  Hormonal Regulation in Males 2 Testosterone—main sex hormone in males. Essential for normal development and functioning of male sex organs. Brings about and maintains the male secondary sex characteristics that develop at puberty. Males are generally taller than females. Broad shoulders, longer legs relative to trunk length. Deeper voices due to a larger larynx with longer vocal cords. Hair growth on the face, chest, other regions. Greater muscular development. 23 ©2020 McGraw-Hill Education  Check Your Progress Describe the process of spermatogenesis. Explain the importance of testosterone to the male reproductive system. 24 ©2020 McGraw-Hill Education  Female Reproductive System 2 Ovaries—the female gonads. one on each side of the upper pelvic cavity. Produce eggs, also called ova (singular, ovum). Produce the female sex hormones estrogen and progesterone. 25 ©2020 McGraw-Hill Education  The Genital Tract 1 Uterine tubes (oviducts, fallopian tubes) extend from the uterus to the ovaries. Are not attached to the ovaries; they have fingerlike projections called fimbriae. After ovulation, the fimbriae sweep the egg into a uterine tube. In the uterine tube, the egg is propelled by ciliary movement toward the uterus. 26 ©2020 McGraw-Hill Education  The Genital Tract 2 An egg lives approximately 6 to 24 hours Fertilization usually takes place in the uterine tube. An embryo implants after several days. Embeds in the uterine lining. 27 ©2020 McGraw-Hill Education  The Genital Tract 3 Uterus—. thick-walled, muscular organ Endometrium—the lining of the uterus. Supplies nutrients needed for embryonic and fetal development. 28 ©2020 McGraw-Hill Education Female Reproductive Organs Organ Function Ovaries Produce eggs and sex hormones Uterine tubes Conduct eggs; location of fertilization Uterus Houses developing fetus Cervix Contains opening to uterus Cancer of the cervix is a common form of cancer in women. Pap test—the removal of a few cells from the cervix for microscopic examination. Hysterectomy—surgical removal of the uterus. Ovariohysterectomy—removal of ovaries and uterus. ©2020 McGraw-Hill Education CHECK POINT 29