Week 20 PHA112 Reproductive System -3 & 4 Student Handout 2023-24 PB.pdf

WEEKS 20 MPharm Programme Reproductive System 3 & 4 Dr Praveen Bhugra PHA112 2022-23 Slide 1 of 28 PHA112 Reproductive System 3 & 4 WEEKS 20 Learning Objectives From this lecture you should be able to:  Understand and explain in detail female reproductive system which will include the or...

WEEKS 20 MPharm Programme Reproductive System 3 & 4 Dr Praveen Bhugra PHA112 2022-23 Slide 1 of 28 PHA112 Reproductive System 3 & 4 WEEKS 20 Learning Objectives From this lecture you should be able to:  Understand and explain in detail female reproductive system which will include the organs, structure, location and function of the ovaries, uterine tubes (fallopian tubes or oviducts), uterus, vagina and the external organs which are collectively called the vulva  Understand and explain regarding the sex glands including those in the breasts.  Understand and describe in detail the female reproductive physiology including  Process of ovulation and hormone that control  Functions of the hormones  Changes that occur in the female at puberty, including the physiology of mensuration Slide 2 of 28 PHA112 Reproductive System 3 & 4 WEEKS Female Reproductive System 20 Essential organs: gonads (ovaries), which produce sex cells (ova) Accessory organs of reproduction Ducts or modified ducts: Uterine tubes (fallopian tubes or oviducts) oviducts, uterus, and vagina Sex glands : including those in the breasts External organs: vulva or pudendum Slide 3 of 28 PHA112 Reproductive System 3 & 4 Female Reproductive System WEEKS 20 1. The ovaries produce secondary oocytes and progesterone, oestrogen (female sex hormones), inhibin and relaxin 2. The uterine tubes transport a secondary oocytes to the uterus and normally the site where fertilization occurs 3. The uterus is the site of implantation of the fertilized ovum, development of the foetus during pregnancy and labor 4. The vagina receives the penis during intercourse and is the passageway for childbirth 5. The mammary gland synthesise, secrete and eject milk for nourishment of newborn Slide 4 of 28 PHA112 Reproductive System 3 & 4 WEEKS Ovaries 20 Structure and location • Paired glands weighing about 3 g each • Resemble large almonds • Attached to ligaments in pelvic cavity on each side of uterus Slide 5 of 28 PHA112 Reproductive System 3 & 4 WEEKS Histological Structure – Ovary 20 • Germinal epithelium: covers surface of the ovary • Tunica albuginea: irregular connective tissue • Ovarian cortex: connective tissue containing follicles surrounded by connective tissue that contain fibers and fibroblasts (stromal cells) – Follicle; oocyte + surrounding cells – Surrounding cells nourish oocyte & secrete oestrogen as follicle grow • Mature (Graafian) follicle - ready to rupture and expel secondary oocyte  ovulation • Post ovulation  corpus luteum – contains remnants of a mature follicle  produces progesterone, relaxin & inhibin until it degenerates into fibrous scar known as corpus albicans Slide 6 of 28 PHA112 Reproductive System 3 & 4 WEEKS 20 Histological Structure – Ovary Day 5 Day 0 Day 10 Day 14 Day 25 Day16 Slide 7 of 28 PHA112 Reproductive System 3 & 4 Oogenesis WEEKS 20 • The formation of gametes in the ovaries – oogenesis • Germ cells from yolk sac migrate to ovary and become potential egg cells called oogonia • In foetus, millions of oogonia produced by mitosis but most of them degenerate (atresia) • Some develop into immature egg cells called primary oocytes during foetal development • 200,000 to 2 millions present at birth • 40,000 remain at puberty but only 400 mature during a woman’s reproductive life • Each month about 20 primary oocytes become secondary oocytes but usually only one survives to be ovulated from Graffian follicle Slide 8 of 28 PHA112 Reproductive System 3 & 4 Oogenesis WEEKS 20 Egg forming cells (oocytes) go through two divisions (Primary, Secondary) • Starts with a 2n=46 primary oocyte that divides, resulting in two n=23 cells, but one is a large secondary oocyte and one is a small 1st polar body that may itself divide • Second division only occurs if secondary oocyte is fertilized. Results in one large n=23 ovum (egg) and one small n=23 2nd polar body • Thus oogenesis results in one large fertilized egg (zygote) and possibly three small polar bodies Slide 9 of 28 PHA112 Reproductive System 3 & 4 Oviducts (uterine or Fallopian tubes) WEEKS 20 • Narrow, 4 inch (10cm) tube that extends from the ovary to uterus • Infundibulum is open, funnel-shaped portion near the ovary • Fimbriae are moving finger-like processes • Ampulla is central region of tube • Isthmus is narrowest portion joins uterus • Fimbriae sweep secondary oocyte into tube • Oocyte moved by cilia lining wall • Zygote reaches uterus in ~7 days Slide 10 of 28 PHA112 Reproductive System 3 & 4 Uterus WEEKS 20 • Responsible for maintenance of fetus during development • Responsible for expelling fetus at end of pregnancy • Site of menstruation 3 inches long by 2 in. Wide and 1 in. Thick • Subdivided into fundus,body & cervix • Interiorly contains uterine cavity accessed by cervical canal Slide 11 of 28 PHA112 Reproductive System 3 & 4 Uterus WEEKS 20 • • • • • Pathway for sperm & site of implantation Fundus: dome-shaped area above tubes Body: tapering central portion Cervix: narrow opening into vagina Uterine cavity: interior of body Slide 12 of 28 PHA112 Reproductive System 3 & 4 Vagina WEEKS 20 • Extends from exterior to cervix • 10cm (4 in.) fibrous muscular canal lined with mucous membrane • Single, small opening that serves as pathway for sperm • Serves as passageway for delivery of baby from uterus • Outlet for menstrual flow • Fornix- recess surrounds cervix • Acid environment- prevents bacterial growth • Smooth muscular layer- adjusts for intercourse or birth • Thin membrane fold can cover vaginal orifice = hymen Slide 13 of 28 PHA112 Reproductive System 3 & 4 WEEKS Vulva (Pudendum) 20 • Vulva: Collective term for female external genitalia • Anterior to the vaginal and urethral opening is the mons pubis – elevation of adipose tissue covered by skin and pubic hair • Labia minora and labia majora – Skin folds that surround vaginal and urethral openings • Clitoris – Small erotic structure located at anterior end of folds of labia minora Slide 14 of 28 PHA112 Reproductive System 3 & 4 WEEKS Mammary Gland 20 • • • • • • Modified suduriferous glands Nipple: pigmented projection with openings Areola: surrounds nipple Internally:15-20 lobes lobules alveoli = milk secreting glands Suspensory (Cooper’s) ligaments suspend breast from deep fascia of pectoral muscles Matures at puberty Slide 15 of 28 PHA112 Reproductive System 3 & 4 WEEKS 20 Physiology of the Breast • Function of mammary gland – Synthesis , secretion and ejection of milk – Functions called Lactation associated with pregnancy and childbirth • Oestrogens develop the ducts system in the breasts • Progestrone develop the milk-secreting glands which are called alveoli • Prolactin stimulate milk synthesis in the alveoli • Oxytocin stimulate milk ejection from the alveoli Slide 16 of 28 PHA112 Reproductive System 3 & 4 WEEKS Female Sex Hormones 20 • Dominant female sex hormones. Oestrogen and progesterone are produced by the ovaries • During foetal development, infancy and childhood the sex hormone production is low • At puberty, hormone production surges, triggering sexual maturation and development of secondary sex characteristics • From puberty to menopause, the sex hormones control the menstrual cycle and produced cyclically • These hormones are produced in higher level during pregnancy by the placenta and inhibit ovulation • Androgen are produced in small amounts by the ovaries and adrenals and also have important functions in women Slide 17 of 28 PHA112 Reproductive System 3 & 4 WEEKS 20 Slide 18 of 28 Other Effects of Oestrogen PHA112 Reproductive System 3 & 4 Other Effects of Progesterone WEEKS 20 1. Converts the oestrogen –primed endometrium to an actively secreting tissue suitable for implantation of an embryo 2. Induces thick, sticky cervical mucus 3. Decreases contraction of fallopian tubes and myometrium 4. Decreases proliferation of vaginal epithelial cells 5. Stimulates breast growth, particularly glandular tissue 6. Inhibits milk inducing effects of prolactin 7. Has feedback effects on hypothalamus and anterior pituitary 8. Increases body temperature Slide 19 of 28 PHA112 Reproductive System 3 & 4 WEEKS 20 Female Reproductive System: Hormones Hypothalamus secretes GnRH GnRH Anterior pituitary releases FSH & LH Ovaries to produce oestrogen and progesterone Slide 20 of 28 PHA112 Reproductive System 3 & 4 WEEKS Female Reproductive System: Reproductive Cycle 20 • Menstrual cycle – Regular changes in uterine lining, resulting in monthly bleeding • Menarche – first menstrual period • Menopause – termination of cycle due to normal aging of ovaries Slide 21 of 28 PHA112 Reproductive System 3 & 4 WEEKS Female Reproductive System: Reproductive Cycle (cont.) 20 Anterior pituitary releases FSH Then releases LH Ovarian follicle matures and secretes oestrogen Triggers ovulation Uterine lining thickens Lining more vascular and glandular Follicular cells become corpus luteum which secretes progesterone Slide 22 of 28 PHA112 Reproductive System 3 & 4 WEEKS 20 Female Reproductive Cycle • Uterine Cycle (menstrual cycle) • Controlled by hormones from ovary • Estrogens  growth of endometrium Progesterone supports endometrium for implantation • Combine cycles = reproductive cycle Slide 23 of 28 PHA112 Reproductive System 3 & 4 WEEKS 20 Female Reproductive Cycle Slide 24 of 28 Follicle Development and Oestrogen Synthesis During the Early and Middle Follicular Phases PHA112 Reproductive System 3 & 4 WEEKS 20 LH Surge and Ovulation Female Reproductive Cycle Slide 25 of 28 PHA112 Reproductive System 3 & 4 WEEKS 20 Female Reproductive Cycle Slide 26 of 28 The Secretory (Luteal) Phase PHA112 Reproductive System 3 & 4 WEEKS 20 Slide 27 of 28 Overview of the Menstrual Cycle PHA112 Reproductive System 3 & 4 WEEKS 20 Further Reading refer to the following textbooks • Ross and Wilson Anatomy and Physiology in Health and illness 13th Edition • Gerard J. Tortora and Byran H. Derrickson Principles of Anatomy and Physiology 13th Edition • Frederic H. Martini Fundamentals of Anatomy & Physiology 7th Edition • Lauralee Sherwood Human Physiology From Cells to Systems 7th Edition • Robert G. Carroll Elsevier’s Integrated Physiology Slide 28 of 28 PHA112 Reproductive System 3 & 4