Female Reproductive System Anatomy PDF

Female Reproductive System Hamza Abu Hilail M.Sc. Physiology  The Female Reproductive System II. The female reproductive system: These organs produce the ova (eggs) and sex hormones provide an environment for internal fertilization and development of the fetus....

Female Reproductive System Hamza Abu Hilail M.Sc. Physiology  The Female Reproductive System II. The female reproductive system: These organs produce the ova (eggs) and sex hormones provide an environment for internal fertilization and development of the fetus. They undergo changes according to the menstrual cycle. Mammary glands are considered part of this system because they nourish the infant.  The Ovaries The ovaries: paired organ is suspended by mesenteries and ligaments. It is surrounded by a fibrous capsule and can be divided into a cortex and medulla.  The cortex houses the developing ova  The medulla holds vascular tissue. The ovary is the site of oogenesis and female sex hormone production.  The Ovaries It responds to follicle-stimulating hormone (FSH) that signals the maturation of an ovum. Typically only one egg is released from an ovary every month, the ovaries alternate in releasing the egg. Hormones that affect the menstrual cycle and female sex organs are also released by the ovaries; estrogen and progesterone.  Ovarian Cycle Ovarian cycle: Females are born with all the potential ova they can produce in a life time. the primordial follicles which consist of a single immature oocyte and a single layer of follicular cells.  These cells respond to FSH and being the maturation of an oocyte. 1. Follicular phase: during the first two weeks of the menstrual cycle one follicle matures up until the stage when it is able to release an oocyte.  Ovarian Cycle Other primordial follicles may get activated but die out along the way. The primordial follicle becomes the primary follicle and continues to develop until it becomes the vesicular follicle. At this point the oocyte is surrounded by follicle cells that the form a fluid filled cavity.  Ovarian Cycle 2. Ovulation (midpoint) phase: at about the mid cycle LH is release to signal the follicle to rupture and release the oocyte from the ovary. The ovum is surrounded by a group of cells that continue to nourish it, they are called the corona radiata. When the egg cell is released it enters the peritoneal cavity but is swept into the fallopian/uterine tubes by fimbriae.  Ovarian Cycle 3. Luteal phase: after ovulation and during the last two weeks of the cycle the follicle that held the oocyte becomes the corpus luteum, it is now considered an endocrine gland that releases progesterone. If no implantation occurs it becomes the corpus albicans (now scar tissue).  Oogenesis 2. Oogenesis in females oogenesis takes several years. During fetal development oocytes undergo: 1. meiosis I but do not complete it; at this point they are called primary oocytes.  At ovulation the primary oocyte completes meiosis I and begins meiosis II 2. meiosis II which is completed only if fertilization occurs.  At the completion of meiosis II the oocyte is called an ovum.  Uterine tubes Uterine tubes: also called fallopian tubes, they take the oocyte and provide a site for fertilization. The tube is lined with ciliated epithelium that gently guides the oocyte towards the uterus. There are also peristaltic waves caused by smooth muscle contraction to aide the movement of the oocyte. There are also non-ciliated cells the nourish the oocyte or embryo on its way to the uterus. sometimes a fertilized egg can implant in a uterine tube and cause a life threatening ectopic pregnancy.  The Uterus The uterus: a thick muscular pouch about the size of a pear that lies in the pelvic cavity superior to the bladder. The function of the uterus is to receive an embryo and provide an environment for its development. During pregnancy it stretches to accommodate the growth of the fetus. When there is no pregnancy the cavity within the uterus is small. The opening of the uterus is at the cervix, during child birth it dilates to allow the child to pass by.  The Uterus The Uterus: The cervix tissue may become infected by HPV human papillomavirus. It can cause abnormal tissue growth including cervical cancer. Uterine wall: composed of three layers: 1. Perimetrium 2. Myometrium 3. Endometrium The thick layer called stratum functionalis (above myometrium) undergoes most of the changes during the uterine cycle.  Uterine cycle Uterine cycle: also called the menstrual cycle, it relates to changes occurring in the endometrium of the uterus that are induced by female sex hormones. Menstrual phase: (days 1-5) during this phase the endometrium is shed  Uterine cycle Proliferative phase: (days 6-14) During this phase the endometrium builds a new stratum functionalis as it responds to rising estrogen levels. As the layer thickens glands release a clear sticky mucus secretion that assist the sperm in finding the egg.  Secretory phase Secretory phase: (days 15-28) during this point the stratum functionalis is highly vascularized and there is secretion of glycoproteins to support a developing embryo in case fertilization occur. These changes are a response to progesterone released by the corpus luteum in the ovary. If there is no fertilization the progesterone levels drop signaling changes that cause death of the stratum functionalis. The arteries constrict cutting out blood supply and suddenly open again but the weak capillaries fragment and the menstrual phase begins again.  The vagina The vagina: also known as the birth canal. It is the opening that leads into the cervix It is located anterior to the anus but posterior to the clitoris and urethral opening. The vagina is also the site where sperm is deposited. This canal is very flexible and it composed of three layers: 1. Adventitia 2. Muscularis 3. Mucosa  The vagina It also has ruggae to stimulate the penis during intercourse and stretch out during childbirth. The mucosa secretes glycogen to maintain healthy beneficial bacteria that produce lactic acid. This creates an acidic environment that is not beneficial to other bacteria or sperm.  External genitalia External genitalia also called the vulva It includes the 1. mons pubis 2. labia majora 3. the clitoris (erectile tissue analogous to the penis) 4. vestibule associated structures( the vaginal and urethral orifice and vestibule glands). 5. labia minora (the mucus membrane sheathes protect the vestibule)  Mammary glands Mammary glands: modified sweat glands that are active in pregnant females to produce milk for the infant. These first appear as rudimentary structures in both men and women. When females reach puberty the ducts grow but the glands do no fully develop; the mas of the breast is mostly adipose.  Mammary glands Mammary glands: During pregnancy glandular alveoli form and produce milk shortly after childbirth. The breast include the nipple and the areola (ring around nipple). The glands consist of lobes that drain into the nipple by lactiferous ducts and lactiferous sinuses where milk accumulates during breast feeling. Lymph vessels drain into the parasternal and axillary lymph nodes.