Anatomy & Physiology For Health Professionals PDF

Anatomy & Physiology for Health Professionals Topic 12: The Reproductive System Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee...

Anatomy & Physiology for Health Professionals Topic 12: The Reproductive System Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  Learning Objectives Locate and describe the male and female reproductive organs. Describe the function of the male and female reproductive organs. Discuss the phases of the menstrual cycle. Discuss the effects of hormonal control on the male and female reproductive systems. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  The Human Life Cycle Mitosis and meiosis are absolutely necessary parts of the human life cycle, needed for cell replacement, repair, & production of the new organisms. Eggs & sperm, with only half as many chromosomes as other cells, are produced by meiosis in specialized organs known as gonads (testes & ovaries). During sexual reproduction, the gametes unite & combine their genetic material. This union is called fertilization. The fertilized egg, a zygote, has 46 chromosomes. The zygote reproduces millions of times via mitosis & develops within Anatomythe female & Physiology Colbert Ankney Lee to change for Health Professions: An Interactivefrom embryoCopyright anEdition Journey, Second fetus. to a©2011 by Pearson Education, Inc. All rights reserved. The early stages of the human life cycle. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved. The Human Reproductive System Reproductive organs are called genitalia. Genitalia are divided into: – Primary genitalia – gonads that produce gametes – Secondary genitalia – other structures that aid in the reproductive process Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  Female Anatomy In females, the primary genitalia are the ovaries. The secondary genitalia are the fallopian tubes, the uterus, the vagina, and the external genitalia called the vulva. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved. Internal female reproductive organs. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  Internal female reproductive organs (continued). Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  Female Reproductive System Ovaries: paired structures. – One on either side of the uterus. – Divided into:  Cortex: contains the eggs  Medulla: contains blood vessels, nerves, & lymphatic tissue surrounded by loose connective tissue. Fallopian Tubes (uterine tubes, oviducts): passageway for the egg to get to the uterus. – Begin as a large funnel, surrounded by ciliated projections called fimbria, leading to a widened area, followed by a longer, narrower portion. – Connected to the superior portion of the uterus. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  The Uterus Located in the pelvic cavity posterior & superior to the urinary bladder, & anterior to the rectum. The cervix is a valve-like portion of the uterus which protrudes into the vagina. Layers of the Uterine walls – Perimetrium – outermost layer – Myometrium – consists of smooth muscle – Endometrium – inner lining of epithelium & secretory cells; highly vascularized; made of 2 layers  Basal layer – responsible for regenerating the uterine lining each month  Functional layer – sheds about every 28 days when a woman has her period Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  The Vagina The vagina is a tube running from the uterus to the outside of the body. Its purpose is to receive the penis during intercourse and allow for the passage of menstrual fluid out of the uterus. The vagina is also known as the birth canal, since its primary function is to allow the movement of a baby out of the uterus during childbirth. The external opening of the vagina may be covered by a perforated membrane, the hymen. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  Reproductive Physiology: Female The female reproductive physiology is closely tied to a regulated cycle, which is hormonally regulated. The menstrual cycle takes about 28 days, & involves the ovaries & uterus. The ovarian cycle involves the monthly maturation & release of eggs from the ovary. The uterine cycle consists of the monthly buildup, decaying, & shedding of the uterine lining. The cycles begin at puberty, & end in menopause. The goal is to release an egg for fertilization, prepare the uterus to receive the fertilized egg, & nourish the fertilized egg should pregnancy result. If pregnancy doesn’t result, the uterine lining will shed & the cycle will begin again. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  Menses & Menstruation The menstrual cycle begins with the first day of menses. Menstruation is the term referring to the actual shedding of the endometrium, the “period” itself. Menses refers to the time during which a woman is menstruating, the time when a woman is having her “period.” Menses usually lasts 4–5 days, but can be longer or shorter in different women, & can vary month to month in the same woman. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  Ovulation From day 1–14 the oocyte, or egg cell, is undergoing a number of developmental changes getting ready for ovulation on day 14. Ovulation is the release of a mature egg from the ovary. The egg travels from the ovary to the uterus, which has been preparing for it. If the oocyte is fertilized by sperm it will implant in the thickened endometrium. If it doesn’t implant within a few days, the endometrium will begin to decay & menstruation will occur within 2 weeks. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  Menstrual Cycle Phases The time between the end of menses & ovulation is known as the follicular, or proliferative, phase. – During this time the endometrium is proliferating, & the follicles (eggs & associated helper cells) are maturing in the ovary. The time between ovulation & menses is known as the luteal, or secretory, phase. – During this phase a structure called the corpus luteum develops in the ovary, & secretion beings in the uterus. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  Oogenesis, Follicle Development, & Ovulation The process of egg production is called oogenesis. Oogenesis begins with the birth of oogonia, or egg stem cells, in the ovary. The oogonia undergo mitosis, producing millions of primary oocytes. This happens very early in a woman’s life, with millions of primary oocytes produced during embryonic development. Women have all the eggs they will ever have 5 months before they are born. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved. Oogenesis  Maturation of a follicle and release of egg. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  Hormonal Control Hormones from the hypothalamus, pituitary, & ovary control the female cycle. Hormone levels are generally controlled by a negative feedback loop. Four hormones control the menstrual cycle: – Estrogen & progesterone from the ovary – Luteinizing hormone (LH) & follicle stimulation hormone (FSH) from the pituitary Estrogen & progesterone levels increase at puberty. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved. Summary of ovarian events during a menstrual cycle 20 Summary of systemic plasma concentrations & ovarian events during the menstrual cycle Small increases in the secretion of gonadotropins (LH & FSH) lead to follicular maturation, including an increase in the synthesis and secretion of ovarian steroid hormones (1-7). Ovulation is provoked by a surge in LH and marks the transition to the luteal phase of the cycle, characterized by high levels of progesterone. (8-14). Eventually, (15) a decrease in LH leads to luteolysis, and the withdrawal of steroid support for a thick, active uterus. 21 Relationships between ovarian & uterine changes during the menstrual cycle 22  Male Anatomy The testes are the primary genitalia, producing the male gamete, sperm. Secondary genitalia include the penis (sperm delivery organ), epididymis, vas deferens, urethra (sperm ducts), & several accessory glands including the prostate gland, the seminal vesicles, & the bulbourethral glands. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved. Male reproductive anatomy. The testis, epididymis, vas deferens, ejaculatory duct, seminal vesicle, & bulbourethral gland are all paired structures. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved. Section of a testis: The seminiferous tubules in this testis are apparent in the area that has been cut away. Sperm cells move from the tubules into the rete testis, and then into the epididymis, first into the efferent ductules, and then into the vas deferens. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  The Testes or Testicles The testes, or testicles, are paired organs suspended in a sac called the scrotum, hanging on either side of the penis. The inside of the testes is divided into 250–300 lobules, each of which contain 1–4 seminiferous tubules Seminiferous tubules contain sperm stem cells and sperm helper cells called Sertoli cells. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  The Penis The penis is a sperm delivery organ that transfers sperm from the male to the female. Internally, the penis contains the urethra, which is a transport passage for both sperm and urine. The penis has 3 erectile bodies, sponge-like tissue with blood spaces. – When a man is sexually aroused the erectile bodies in the penis will become engorged with blood, stiffening & expanding the penis, producing an erection. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  Epididymis &The vas deferens Epididymis – Lies posterior & lateral to the testes. – Highly coiled tube, made of epithelium & smooth muscle. – Sperm mature here. Vas deferens – Short tube lined with epithelium, has a thick smooth muscle layer, & is surrounded by a connective tissue layer. – Posterior to the bladder, the vas deferens joins the seminal vesicle to form the ejaculatory duct, which then passes through the prostate gland & empties into the urethra. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  Accessory Glands in the male reproductive system Seminal vesicles – Posterior to the bladder – Add sugar & chemicals to the sperm Prostate gland – Surrounds the urethra just inferior to the bladder – Add fluid to liquefy the semen & protect the sperm from the acid environment of the vagina by secreting an alkaline substance Bulbourethral glands – Inferior to the prostate – Add mucus to the semen The expulsion of semen from the body is called ejaculation. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  Male Reproductive Physiology Sperm production, in the seminiferous tubules of the testes, is a continuous process beginning when a boy reaches puberty & continuing until death. Sperm production, called spermatogenesis, is much less complicated than control of ovulation. – Spermatogonia line up against the walls of the tubules. – Mature sperm cluster near the lumen of the tubules. – Sperm then travel from the seminiferous tubules to the epididymis where the sperm spends about 2 weeks maturing & gaining the ability to swim. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved. Spermatogenesis. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  Spermatogenesis Relation of Sertoli cells & germ cells in the seminiferous tubules: Sertoli cells support spermatogenesis in response to testosterone Differentiation & FSH. Different stages of spermatogenesis takes Meiosis II place in different compartments. Meiosis I A, B: spermatogonia C, D: primary spermatocytes E: secondary spermatocytes F: spermatids G: spermatozoa 32  Spermatogenesis (continued). Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  Hormonal Control of Male Reproduction Testosterone is the most important sex hormone. In utero, the secretion of testosterone masculinizes the fetus. Those not exposed to testosterone become female. After birth there is little testosterone secreted until puberty. This small amount of testosterone inhibits GnRH. At puberty, 2 hormonal changes occur: – Testosterone secretion by the testes increases. – Testosterone no longer inhibits GnRH; hence FSH & LH, further enhance testosterone production, creating a major positive feedback loop. Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.  Male Secondary Sexual Characteristics Testosterone secretion at puberty brings about the development of male secondary sexual characteristics including: – Body, facial, & pubic hair growth – Deepening of the voice – Increased muscle & bone mass Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition Copyright ©2011 by Pearson Education, Inc. Colbert Ankney Lee All rights reserved.