Bioc700
Physiology
Table of Content
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1. Structure And Function Of Female Reproductive Organs…….
1.1 Outer structures of reproductive system ……………………
1.2 Interior structures of reproductive system ………………
2. Functions of Ovarian…………………………………………
2.1 Oogenesis………………………………………………………
2.2 Secretion of Ovarian Hormones……………………………..
2.2.1 Mechanism Action of Estrogen and progesterone ……….
3.The Cycle of Female Reproductive ……………………………..
3.1 The Cycle of Ovarian …………………………………………..
3.2 The Cycle of Endometrial ……………………………………..
List of Figures
Figure(1): The outer structures of female reproductive ………….
Figure(2): The interior structures of female reproductive ……….
Figure(3): Oogenesis…………………………………………………
Figure(4): Steroid hormones mechanism action on the target cell……………………….……………………………………………
Figure (5) : The cycle of female reproductive summary ……..
Figure (7) :Passive feedback inhibition of the LH and FSH through pre-ovulatory stage……………………………………….
Figure (7) :Positive feedback stimulation of the LH surge ,which elicits ovulation………………………………………………………
Figure (8) :Passive feedback inhibition of the LH and LH through pre-ovulatory stage……………………………………….
1. Structure And Function Of Female Reproductive Organs
The system of female reproductive consists of outer and interior organs.
1.1 Outer Structures of Reproductive System
Outer structures of reproductive system are the tow labia , mons pubis , clitoris, vestibule of the vagina and vestibular glands as show in the picture(1) below. The vulva functions as sensory tissue for sexual arousal, urine flow and prohibit entry of any foreign substance into system of urogenital (1).
Figure(1): The outer structures of female reproductive (3).
1.2 Interior Structures of Reproductive System
Interior structures of reproductive system are pair of ovaries and the of pair fallopian tubes (also called uterine tubes or oviducts), the uterus, the cervix, and the vagina as show in the figure(2) below.
The ovaries are primary organs located one on each side of the uterus. Each ovary is consisting of connective tissue and structures embed within it named as follicles. This follicles begin as primordial follicles, which are composed of a one oocyte encompassed by an one layer of cells named follicle cells. Cells of this layer increase to more than one layer, when follicle develops, named granulosa cells . Granulosa cells are accountable for synthesis and releasing the ovarian hormones, estrogens and progesterone. In final development steps , the granulosa cells proliferate, and the external layer cell is transform into different type of cell named as theca cells. Theca cells are responsible for synthesis androgens which are needed in estrogen synthesis (2).
The parties of fallopian tubes are close to upper part of ovaries but not linked to them. Each fallopian tube opened as shape of funnel and has long prominences like finger. The other parties of the fallopian tubes are linked to the uterus. When an egg is released from the ovary, it is it is pushed by prominences motion to entire fallopian tube then to uterus. Oviducts are also place of fertilization. The uterus is a blank, muscular organ has thick walled located between rectum and bladder. It functions as the menstrual flow source and place of the fetus development through pregnancy. The cervix is lower narrow part of the uterus. The vagina is the vagina is tube extending from the uterus to the external genitals. It serves as an exit pathway for blood of menstrual and for the fetus through childbirth, also it enter pathway sperm(1).
Figure(2): Interior Structures of Reproductive System (2).
2. Functions of Ovarian
2.1 Oogenesis
oogenesis is formation process of ova from oogonia or primitive germ cells as show in the figure(3) below. Oogonia increase in number by mitotic division to form primary oocytes through period from conception until seventh month. then, primary oocytes start a first meiotic division by replicating their DNA. The division of primary oocytes do not complete in fetus at birth, all the eggs existing are primary oocytes with 46 chromosomes which have two sister chromatids. The cells remain in a state of meiotic arrest until puberty and before ovulation . When puberty starts, only primary oocytes destined for ovulation continue the first mitotic division and complete this division before ovulation, producing two daughter cells with 23 replicated chromosomes which have tow chromatids. One of the two daughter cells, named a secondary oocyte. it keeps most of the cytoplasm through the mitotic division . The other daughter cell, named the first polar body. It extremely tiny and do not has any function. Only if the secondary oocyte is fertilized does the second meiotic division take places in a fallopian tube. This second meiotic division produces two daughter cells with 23 replicated chromosomes which have one chromatids. One of the two daughter cells, named a ovum. It keeps most of the cytoplasm through the mitotic division . The other daughter cell, named the second polar body. It extremely tiny and do not has any function. The final result of oogenesis is one ovum for each primary oocyte (4).
Figure(3): Oogenesis(4).
2.2 Secretion of Ovarian Hormones
Ovaries has endocrine function to produce hormones which includes: estrogen and progesterone. Oestrogens are steroid hormones and primary released by granulosa cells in high amounts at puberty which lead to growth and development of genital organs and appearance of secondary sex characters. After ovulation, it is released by the corpus luteum Progesterone are second steroid ovarian hormones and primary released by corpus luteum after ovulation induces chickening of endometrium and raised endometrial secretions, but its secreted in little amounts by the granulosa cells and theca cell. Inhibins are peptide hormone released by corpus luteum and granulosa cells(5).
2.2.1 Mechanism Action of Oestrogen and Progesterone
Oestradiol and progesterone are a lipophilic hormones, they act on intracellular receptors, that can activate or deactivate transcription in the nucleus. Estradiol binds with a target ? receptor or ? receptor in the cytoplasm of the cell. Progesterone binds with target nuclear receptors. Once lipophilic hormone binds to its receptor , prompts mRNA formation. After that, mRNA interacts with ribosomes to produce specific proteins that do the impacts of these hormones on the target cell.
Figure(4): Steroid hormones mechanism action of on the target cell(4).
3. Ovarian Function Regulation
3.The Cycle of Female Reproductive
cycle of female reproductive is initiated when female arrives puberty and duplicates itself each 28day. Cycle of reproductive, also named as the cycle of menstrual, generates from specific hormones sequencing of hypothalamus, pituitary gland and ovaries that lead to ovulation. If fertilization does not result, menstruation follows. Menstrual cycle includes tow cycles which are happening at the same time: the ovarian cycle in which ovulation take place, and the endometrial cycle in which menstruation take place. Ovulation separates Menstrual cycle reproductive cycle at the middle part of cycle. Figure (4) summarizes the Female reproductive cycle.
Figure (5) : The cycle of female reproductive summary (5).
3.1 The Cycle of Ovarian
The cycle of ovarian cycle is the sequence of events related with a developing oocyte inside the ovaries.The ovarian cycle consists of two stages: the pre-ovulatory or follicular stage and the postovulatory or luteal stage, insular by ovulation.
Follicular Stage
The Stage of follicular initiates from the1th day of the cycle to ovulation. The duration of this phase is about 10-14days. The hypothalamus prompted this phase by secretes gonadotropin-releasing hormone(GnRH) as show in the figure(6). GnRH induces the secrete of follicle-stimulating hormone(FSH),which stimulates the ovary to produce follicles . Addionally, it stimulates secrete luteinizing hormone, which responsible to last development of follice and later laceration of mature follicle. Increasing levels of estrogen from granulosa cells due to FSH prompt proliferation of endometrium.
Figure (6) :Negative feedback inhibition of the LH and FSH through pre-ovulatory stage(5).
Ovulation
Ovulation is released of oocyte due to ruptures of mature follicle in response to LH surge as show in the figure(7), after that, oocyte gets in the fallopian tube and completes ride to uterus. It usually happens on14th days. If oocyte fertilizes by sperm, pregnancy happens.
Figure (7) :Positive feedback stimulation of the LH surge ,which elicits ovulation.
Luteal Stage
The stage of luteal initiates from the 15 th day to 28 th day of the reproductive cycle. During this phase ,corpus luteum shapes when follicle ruptures and releases oocyte. It is secretes high amounts of progesterone and estrogen hormone, which inhibit secretion of FSH and LH from anterior pituitary gland as show in the figure(8). Progesterone induces chickening of endometrium and raised endometrial secretions(glycogen, mucous, lipids and other substance ).These variations to ready endometrium for implantation.
Figure (8) :Negative feedback inhibition of the LH and LH through pre-ovulatory stage(5).
3.2 The Cycle of Endometrial
The cycle of endometrial is events administered by hormonal changes in consistency with ovarian cycle. it consists of four stages.
Proliferative Stage
Proliferative stage initiates from the5th day of the cycle to ovulation and it synchronizes with follicular phase. In this phase, the large amount of estrogen lead to increased thickness of lining of uterus, number of blood vessels and magnified of glands.
Secretory Stage
Secondary stage initiates from the 15 th day to 28 th day of the reproductive cycle and it synchronizes with luteal phase. In this phase, the large amount of estrogen and progesterone lead to increased thickness of lining of uterus, number of blood vessels and magnified of glands. So that, the uterus become ready for pregnancy, if implantation was to event.
Ischemic Stage
Ischemic stage initiates, if implantation was not to event. In this phase, the decline pettishly of estrogen and progesterone amounts lead to arterioles spasm and shedding of lining of uterine. Then, menstrual stream initiates
Menstrual Stage
Menstrual stage initiates from the 28 th day to 5 th day of the reproductive cycle. In this phase, the falling of estrogen and progesterone levels lead to arterioles spasm which present in outer layer of endometrium. So that , blood cannot reach to tissue , these tissues die and split from live tissues then shed from surface lining of uterine, which impetus tear of blood vessels and bleeding that exit from uterus through cervix into vagina.
REFREANCES
1- Indu Khurana (2018)Concise Textbook of Human Physiology, Indu Khurana Elsevier Health Sciences, 3rd Edition.
2- Cindy L. Stanfield (2016) Principles of Human Physiology, Global Edition Pearson Education Limited,6th Edition.
3- Rumi Michael Leigh(2018) Anatomy and Physiology : The Reproductive System, Rumi Michael Leigh.
4- CTI Reviews (2016) Hole’s Human Anatomy and Physiology, Cram101 Textbook Reviews, 11th Edition.
5- Ian Peate (2017)QR code for Fundamentals of Anatomy and Physiology Workbook:
A Study Guide for Nurses and Healthcare Students, John Wiley ; Sons.
6- Kaplan Medical)2018)USMLE Step 1 Lecture Notes 2018: Physiology , Simon and Schuster.
