Reproductive-System-Handout.pdf

INTRODUCTION Medulla - contains blood vessels, lymphatic vessels, and nerve GONADS Gonads are glands that produce OVA OR EGGS hormones and reproductive cells that are Ovum - a female re...

INTRODUCTION Medulla - contains blood vessels, lymphatic vessels, and nerve GONADS Gonads are glands that produce OVA OR EGGS hormones and reproductive cells that are Ovum - a female reproductive cell that involved in reproduction and other fuses with sperm in the process of functions of the body. fertilization Follicle Cells - special cells that TESTES surround and support an egg cell (ovum) Male gonads within the ovary. The testes are responsible for making sperm and are also involved in FOLLICLE producing a hormone called An ovum plus its associated follicle cells testosterone. is termed a follicle. OVARY ○ Primary Follicle - These follicles Female gonads may either remain in a dormant state Glands located on either side of the for years or start to grow and develop. uterus are responsible for producing ○ Mature Follicle - Once a follicle the egg cells. reaches its maturity, its ovum will be capable to be released during REPRODUCTIVE HORMONES ovulation Facilitates sexual behavior; ○ Rudimentary Follicle - Some Parental care; follicles never fully mature and Prepare reproductive ducts to receive instead undergo a process known as gametes; and atresia, where they degenerate and Support zygote are reabsorbed by the body. MAMMALIAN REPRODUCTIVE OVULATION SYSTEM The process in which an egg is released from an ovary ○ Oviduct - Also known as the fallopian tube. After an ovary releases an egg during ovulation. ○ Mature Ovum - A mature ovum is an egg cell that is fully developed and ready to be fertilized by a sperm cell. Tunica Albuginea - A dense connective tissue capsule that serves as a protective ○ Implantation - The blastocyst then layer for the ovary. attaches itself to the lining of your Cortex - The ovarian cortex consists of uterus (the endometrium) ovarian follicles. ○ Menstruation - Menstruation is a woman's monthly bleeding, often  called your “period.” When you It stores the sperms until they are ready menstruate, your body discards the for maturation. monthly buildup of the lining of your uterus (womb). VAS DEFERENS Also known as the tail of the epididymis EMBRYONIC IMPLANTATION Propels the sperm to the urethra. EJACULATION SEMINAL VESICLE The release of semen through the penis Produces about 60-70% of the during orgasm. component of the semen made up of thick fluid that contains substances that help the sperm survive in the female reproductive organ. PROSTATE GLAND Produces about 20-30% of the component of the semen made up of a milky alkaline fluid that protects the sperm by neutralizing acidity in the vagina. BULBOURETHRAL GLAND Produces the pre-ejaculate that helps in SEMINIFEROUS TUBULE lubricating the female reproductive functional unit of the testis that organ. generates millions of sperm DEVELOPMENTAL ASPECTS OF STRAIGHT TUBULE REPRODUCTIVE SYSTEM Also known as the tubuli recti. Discharge sperm from seminiferous PRENATAL DEVELOPMENT tubule to rete testis. Early embryonic stage ○ The reproductive system begins to RETE TESTIS form very early in embryonic A network of small tubes that serves as development. By the 5th week of a collecting reservoir for sperm within gestation, the embryo has structures the testes. called gonadal ridges, which will eventually develop into the gonads EFFERENT DUCTULES (testes or ovaries). Small, highly convoluted and delicate Sex Determination tubules that connect rete testis cavities ○ Around the 7th week, genetic factors with the head of the epididymis determine whether the gonads will develop into testes or ovaries. This HEAD OF EPIDIDYMIS depends on the presence of the SRY gene on the Y chromosome.  ○ If the embryo has an XY ○ males being able to produce sperm chromosome pair (typically male), the continuously and females releasing SRY gene activates, leading to the eggs periodically. development of testes. In the absence of this gene (XX AGING chromosome pair, typically female), Menopause ovaries begin to develop. ○ Typically occurs between ages 45- 55, marks the end of menstrual INFANCY AND CHILDHOOD cycles and the ability to conceive Reproductive System at Rest naturally. It occurs when the ovaries ○ After birth, the reproductive organs stop releasing eggs and hormone are present but inactive. production (especially estrogen) Male decreases significantly. ○ In males, the testes are in the Andropause scrotum, but they don’t produce ○ Men do not have a sudden end to sperm. fertility like women, but testosterone Female levels gradually decline with age. ○ In females, the ovaries contain all the This can lead to changes such as eggs (oocytes) a female will ever reduced libido, decreased muscle have, but these eggs are immature mass, and sometimes erectile and dormant. dysfunction. PUBERTY Onset Puberty FEMALE REPRODUCTIVE SYSTEM ○ It starts when the hypothalamus begins to release gonadotropin- OVARIES releasing hormone (GnRH), which An internal view of an ovary reveals signals the pituitary gland to produce many tiny saclike structures called luteinizing hormone (LH) and follicle- ovarian follicles. Each follicle stimulating hormone (FSH). These consists of an immature egg, called hormones stimulate the gonads to an oocyte, surrounded by one or produce sex hormones. more layers of very different cells called follicle cells. ADULTHOOD Reproductive Maturity OVULATION ○ The reproductive system is fully As a developing egg within a follicle developed. begins to ripen or mature, the follicle Sexual Function enlarges and develops a fluid-filled ○ sexual function is supported by a central region called an antrum. At balance of sex hormones. These this stage, the follicle, called a hormones regulate processes like the vesicular follicle or Graafian (graf′e- menstrual cycle in women and sperm an) follicle, is mature, and the production in men. developing egg is ready to be ejected Reproductive Capabilities  from the ovary, an event called inches) long and extends medially ovulation. from an ovary to empty into the superior region of the uterus. Unlike in the male duct system, which is continuous with the tubule system of the testes, there is little or no actual contact between the uterine tubes and the ovaries. The distal end of each uterine tube expands as the funnel-shaped infundibulum, which has fingerlike projections called fimbriae (fim′bre-e) that partially surround the ovary. Sagittal section of a human ovary showing Uterus the developmental stages of an ovarian The uterus (u′ter-us; “womb”), follicle. located in the pelvis between the urinary bladder and rectum, is a hollow organ that functions to receive, retain, and nourish a fertilized egg. The major portion of the uterus is referred to as the body. Its rounded region superior to the entrance of the uterine tubes is the fundus, and its narrow outlet, which protrudes inferiorly into the vagina, is the cervix. Vagina A thin-walled tube 8 to 10 cm (3 to 4 inches) long. It lies between the bladder and rectum and extends from the cervix to the body exterior. Often called the birth canal, the vagina provides a passageway for the delivery of an infant and for the menstrual flow to leave the body. DUCT SYSTEM External Genitalia and Female Perineum Uterine Tubes The female reproductive structures that are Form the initial part of the duct located external to the vagina are the system. They receive the ovulated external genitalia. The external genitalia, oocyte and provide a site where also called the vulva, include the mons pubis, fertilization can occur. Each of the uterine tubes is about 10 cm (4 labia, clitoris, urethral and vaginal orifices, enter meiosis I but stop at prophase and greater vestibular glands. I. A female is born with all the primary Mons Pubis - (“mountain on the oocytes she will ever have, and these pubis”) is a fatty, rounded area are arrested in prophase I until overlying the pubic symphysis. After puberty. puberty, this area is covered with Puberty and Menstrual Cycles pubic hair. Resumption of Meiosis: Each month, Labia Majora - Running posteriorly during the ovarian cycle, a few from the mons pubis are two primary oocytes resume meiosis. elongated hair-covered skin folds However, only one typically Labia Minora - Enclose two delicate, completes meiosis I each cycle. hair-free folds Secondary Oocyte Formation: The Vestibule - The labia majora is primary oocyte completes meiosis I, enclosed with this region, which dividing into a secondary oocyte and contains the external openings of the a smaller polar body (which usually urethra,* followed posteriorly by that degenerates). The secondary oocyte of the vagina then enters meiosis II but is arrested Clitoris - Just anterior to the in metaphase II. vestibule. A small, protruding Fertilization structure that corresponds to the Completion of Meiosis: The male penis secondary oocyte will only complete Greater Vestibular Glands - A pair meiosis II if fertilization occurs. Upon of mucus-producing glands. Their fertilization, it divides to form an ovum secretion lubricates the distal end of (mature egg) and a second polar the vagina during intercourse body. Perineum - The diamond-shaped Ovum region between the anterior end of The mature egg, or ovum, is then the labial folds, the anus posteriorly, available to be fertilized by sperm. and the ischial tuberosities laterally. OVARIAN CYCLE FEMALE REPRODUCTIVE FUNCTIONS The ovarian cycle is the series of events that AND CYCLES occurs in the ovaries to produce and release eggs and is divided into three main phases: OOGENESIS The process by which the female gametes, Follicular Phase or eggs, are produced. It occurs in the Days 1-14 (Varies): This phase ovaries and involves several stages: begins on the first day of menstruation. During this time, Fetal Development several follicles start to develop in Oogonia Formation: In a female response to follicle-stimulating fetus, germ cells called oogonia hormone (FSH). Each follicle multiply by mitosis. contains an oocyte. Primary Oocytes: Oogonia develop Dominant Follicle: Usually, one into primary oocytes. These oocytes follicle becomes dominant and  continues to mature, while the others which is the most potent form of regress. estrogen. Estrogen Production: As the follicle Effects: Estrogen promotes the matures, it produces estrogen, which growth and maturation of ovarian helps prepare the endometrium follicles, the thickening of the (lining of the uterus) for potential endometrial lining (uterine lining), implantation. and the development of secondary Ovulation sexual characteristics such as breast Day 14 (Approximate): A surge in development and widening of the luteinizing hormone (LH), triggered hips. by rising estrogen levels, causes the Progesterone: Prepares the endometrium mature follicle to release the for potential implantation of a fertilized egg secondary oocyte from the ovary. and helps maintain pregnancy if fertilization This process is ovulation. The occurs. released egg travels down the Luteal Phase: After ovulation, the fallopian tube, where it may meet ruptured follicle transforms into the sperm for fertilization. corpus luteum, which produces Luteal Phase progesterone. This hormone peaks Days 15-28 (Approximate): After during the luteal phase of the ovulation, the remnants of the menstrual cycle. dominant follicle transform into the Effects: Progesterone further corpus luteum, which produces thickens the endometrial lining and progesterone and some estrogen. makes it more suitable for Progesterone Role: Progesterone implantation. If implantation does not helps to further prepare the occur, progesterone levels drop, endometrium for implantation. If leading to the shedding of the fertilization does not occur, the endometrial lining (menstruation). corpus luteum degenerates, leading Androgens: Are male hormones present in to a decrease in progesterone and both men and women. In females, they are estrogen. converted into estrogen and play a role in Menstruation: The drop in hormone overall hormone balance and reproductive levels triggers the shedding of the health. endometrial lining, resulting in Small Amounts: The ovaries produce menstruation and the beginning of a androgens like testosterone and new cycle. androstenedione in small amounts. These androgens can be converted HORMONE PRODUCTION BY OVARIES into estrogen by peripheral tissues. Estrogen: crucial for the development and regulation of the female reproductive system HORMONAL REGULATION OF THE and secondary sexual characteristics. OVARIAN CYCLE Follicular Phase: During the early The production of these hormones is tightly part of the menstrual cycle (follicular regulated by the hypothalamic-pituitary- phase), developing ovarian follicles ovarian axis: produce estrogen, primarily estradiol,  Hypothalamus: Releases vagina. This bleeding typically lasts gonadotropin-releasing hormone 3-7 days. (GnRH), which stimulates the Proliferative Phase (Days 6-14) pituitary gland. Overview: This phase follows Pituitary Gland: Releases follicle- menstruation and involves the stimulating hormone (FSH) and regeneration and thickening of the luteinizing hormone (LH) in response endometrial lining. to GnRH. Hormonal Changes: As the follicular ○ FSH: Stimulates the growth of phase of the ovarian cycle ovarian follicles and the progresses, rising levels of estrogen production of estrogen. produced by the developing ovarian ○ LH: Triggers ovulation and follicles stimulate the endometrium to supports the corpus luteum’s rebuild and grow. production of progesterone. Physical Changes: The endometrial Ovaries: Respond to FSH and LH by lining regenerates, becoming thicker producing estrogen and and more vascular to prepare for a progesterone in varying amounts potential implantation. The phase throughout the menstrual cycle. ends with ovulation, which occurs around day 14 of a typical 28-day UTERINE CYCLE cycle. Menstrual cycle, a series of cyclic changes Menstruation and the New Cycle that the endometrium (mucosa of the uterus) Hormonal Drop: The decrease in goes through each month as it responds to progesterone and estrogen from the changing blood levels of ovarian hormones. degenerating corpus luteum causes the endometrial lining to break down The three phases of the menstrual cycle and be shed, marking the start of a are as follows: new menstrual phase and the beginning of the next cycle. Menstrual Phase (Days 1-5) Reset: This hormonal drop triggers Overview: This phase marks the the menstrual bleeding beginning of the cycle and is (desquamation) and the cycle starts characterized by the shedding of the anew. endometrial lining, resulting in menstrual bleeding. Hormonal Changes: Low levels of Male Reproductive - Ferrer estrogen and progesterone from the previous cycle lead to the breakdown MALE REPRODUCTIVE SYSTEM of the endometrial lining. FUNCTIONS Physical Changes: The endometrial lining, which was thickened in The chief role of the male in the preparation for a potential reproductive process is to produce sperm implantation, is expelled from the and the hormone testosterone. body along with blood through the SPERMATOGENESIS- process of sperm duct that allows sperm to enter into production epididymis which is crucial for reproduction. Under the seminiferous Processes: tubules are the other soft connective - The process is begun by primitive tissue called interstitial cells which stem cells called spermatogonia is relevant for androgen and found in the outer edge,or periphery, testosterone production of each tubule and it will go mitotic divisions Duct System - From the division it will produce two The duct system are composed of stem cells, Cell B will proceed into three primary parts: the epididymis, ductus primary spermatocyte deferens and the urethra - Primary spermatocyte will mature into secondary spermatocyte Epididymis- The epididymis is the first part - Secondary spermatocytes shall of the male duct system and provides a undergo further changes until it temporary storage site for the immature reaches spermiogenesis. sperm. MALE PRIMARY DIVISIONS Ductus deferens (vas deferens)- propels live sperm from their storage sites—the epididymis and distal part of the ductus deferens—into the urethra. Testis - In the cross-section of the Testis, it is inherent that the presence of spermatic cord, is found which is a connective tissue sheath that encloses blood vessels, nerves and Urethra- extends from the base of the ductus deferens. The tunica urinary bladder to the tip of the penis, is the albuginea protects the testis and the terminal part of the male duct system, serves extensions of these capsules divide as the passage for the sperm cells to into lobules. ejaculate. - The lobules contain seminiferous tubules which are crucial in forming sperm cells, found in the seminiferous tubules are another lobules called rete testis which is a  Internal fertilization is the union of an egg and sperm cell during sexual reproduction External Genitalia inside the female body. - The male external genitalia include the scrotum and the penis. The From fertilization through week 8, the scrotum is a divided sac of skin with embryonic period, the conceptus is called an sparse hairs that hangs outside the embryo, and from week 9 through birth, the abdominal cavity, between the legs at fetal period, the conceptus is called a fetus. the root of the penis. - The penis functions to deliver sperm Viviparity is development of the embryo into the female reproductive tract. inside the body of the mother, with the The skin-covered penis consists of a maternal circulation providing for the shaft, which ends in an enlarged tip, metabolic needs of the embryo's the glans penis. development, until the mother gives birth to - Internally, the spongy urethra is a fully or partially developed juvenile that is surrounded by three elongated areas at least metabolically independent. of erectile tissue, a spongy tissue that Oviparity. Oviparous animals are animals fills with blood during sexual that reproduce by depositing fertilized excitement. This causes the penis to zygotes outside the body (known as laying or enlarge and become rigid called spawning) in metabolically independent erection/ tumescence which is vital incubation organs known as eggs, which for copulation. nurture the embryo into moving offsprings known as hatchlings with little or no FUNCTION AND EVOLUTION embryonic development within the mother. POTENCY AND FERTILITY DELAYS IN GESTATION Fertility refers to the ability of the female to Gestation lasts from conception to hatching produce fertilizable eggs or of the male to or birth. It includes fertilization, implantation produce sperm in sufficient numbers to (in some species), and development. In achieve fertilization. A male producing some species of mammals, the onset of each insufficient numbers of sperm is infertile or stage may be prolonged or delayed. sterile. In some species of mammals, the onset of Potency refers to the ability of the male to each stage may be prolonged or delayed. engage in copulation. Impotence results from For example, delayed fertilization occurs in the failure to achieve an erection. some bats. In delayed implantation, known only in EXTERNAL AND INTERNAL mammals, fertilization and early FERTILIZATION development occur, but the embryo fails to implant in the uterus. In most cases, delayed External fertilization is common among implantation is tied to the annual seasonal invertebrates and primitive vertebrates. Eggs cycle. In some marsupials, such as and sperm meet outside the body. kangaroos and wallabies, however, delayed Comparing to humans, the testes of implantation of the blastocyst is tied to the the frog is also suspended by a presence of a young kangaroo in the pouch, dorsal body called the mesorchium. termed a joey. Suckling by an older joey in Meanwhile in rabbits, the testes is the pouch inhibits implantation of the next also covered by tunica albuginea blastocyst, a type of delay referred to as which has also the extension of the embryonic dispause. lobules that are bounded by seminiferous tubules In delayed development, known from In each testis, all the seminiferous several species of bats, fertilization and tubules open into a network, called implantation occur on schedule, but the rete testis. It communicates by subsequent growth of the embryo is slow. many fine ductules, the vasa efferentia into the epididymis. The vasa efferentia are lined internally by Pictures *jhonna and joms* ciliated epithelium. Female Reproductive System Male Reproductive System All of the testes of other vertebrates are paired, in which it is suspended from the dorsal wall of the coelom by a mesentary, which was the mesorchium. EXCEPT the cyclostomes (jawless fishes), elasmobranch (sharks) and some teleosts (ray-finned fishes). In Amniotes (egg-laying animals) sperm form within the luminal wall of the seminiferous tubules, which lack subcompartments. Resident primordial germ cells, more commonly called spermatogonia at this stage, divide by mitosis. Meanwhile in Anamniotes (egg- laying aquatic animals) fishes and amphibians, sperm are produced in clones, each located within a cyst or follicle, all of which are housed in separate tubular compartments within the testes The testes of the frog is an ovoid body lying close which lies close to the fore end of the kidney.  Rabbits and humans share the same In male sharks, rays, chimaeras, and features in duct system It goes by some placoderms, the pelvic fins are the same processes in which Sperm specialized as claspers. cells pass through a series of ducts In amphibians, most of the time their to reach the outside of the body. fertilization is external, however Meanwhile in fishes, amniotes which some species such as male includes the frog, their duct system salamander species in which it is intact with mesonephric ducts produces a spermatophore, which consists of a cap of sperm on top of a gelatinous pedestal. Mammals and Reptiles has the most common similarity as both shares the same external genitalia used in reproduction which are the penis.  In addition, insectivores, bats, rodents, carnivores, and most primates except humans have a baculum (os penis), a permanent bone located within the connective tissue of the penis to stiffen it. Crocodilians share the same characteristics but except it is relatively longer because it projects farther in the cloaca of a female The penis of the rabbits has almost the exact same features as of humans. Its anatomy were composed of three (3) spongy, vascular longitudinal columns around urethra, called as (1) corpora spongiosum and above it (2) two corpora cavernosa.