NOTA FEMALE REPRODUCTIVE SYSTEM.pdf

# Structure of the female reproductive system The structure of the female reproductive system comprises external and internal organs that facilitate reproduction and hormonal regulation [1](#page=1). ## 1. Structure of the female reproductive system The female reproductive system is anatomically and physiologically distinct from the male system, with both producing specialized germ cells known as gametes. The female gamete is the secondary oocyte, produced in the ovaries. The primary functions of the female reproductive system include producing estrogen and progesterone, forming ova, receiving spermatozoa, serving as the site for fertilization and fetal development, and facilitating childbirth (parturition). The system is divided into external organs (external genitalia), internal organs, and mammary glands. The perineum is a diamond-shaped region between the thighs and buttocks that contains the external genitalia and anus in both sexes [1](#page=1) [2](#page=2). ### 1.1 External genitalia (vulva) The external genitalia, collectively known as the vulva, include several structures: #### 1.1.1 Mons pubis The mons pubis is an elevation of adipose tissue located over the symphysis pubis. It consists of fat and skin and is covered with pubic hair during puberty [2](#page=2). #### 1.1.2 Labia majora These are a pair of skin folds that form the boundaries of the vulva. They are composed of pigmented skin, fibrous tissue, and adipose tissue containing sebaceous and sweat glands. The lateral aspects of the labia majora are covered with pubic hair during puberty [2](#page=2). #### 1.1.3 Labia minora The labia minora are smaller folds of skin, lacking hair, located medial to the labia majora. They contain numerous sebaceous glands and meet anteriorly to form the prepuce of the clitoris [3](#page=3). #### 1.1.4 Clitoris This is a small erectile tissue and nerve mass situated at the anterior junction of the labia minora. The labia minora enclosing the clitoris form the clitoral prepuce, while the glans clitoris is the exposed part [3](#page=3). #### 1.1.5 Vestibule The vestibule is the area enclosed by the labia minora. It contains two openings: the urethral orifice anteriorly (between the clitoris and vaginal orifice) and the vaginal orifice posteriorly (between the urethral orifice and the anus) [3](#page=3). #### 1.1.6 Hymen The hymen is a thin mucous membrane that partially covers the vaginal orifice but is incomplete to allow for menstrual flow [3](#page=3). #### 1.1.7 Vestibular glands There are two types: Greater Vestibule Glands and Lesser Vestibule Glands. Their function is to secrete mucus to lubricate the vulva [3](#page=3). ### 1.2 Internal genitalia The internal organs of the female reproductive system include the vagina, uterus, fallopian tubes, and ovaries [1](#page=1). #### 1.2.1 Vagina The vagina is a fibromuscular canal lined with stratified squamous epithelium. It extends from the vaginal orifice to the cervix, situated at a 45-degree angle between the urinary bladder anteriorly and the rectum and anus posteriorly. The junction between the vagina and the cervix forms four fornices (vaults). The vaginal wall consists of three layers: an outer areolar tissue layer, a middle smooth muscle layer, and an inner stratified squamous epithelium layer. The smooth muscle layer allows the vagina to distend during sexual intercourse and childbirth. The vaginal surface is kept moist by cervical secretions, maintaining an acidic pH of 3.5–4.9, which inhibits microbial growth. Glycogen in the vaginal mucosa is broken down by *Lactobacillus acidophilus* to produce organic acids, contributing to the acidic environment. Semen contains alkaline components that neutralize this acidity. Blood supply and venous drainage are from branches of the internal iliac arteries and veins. The vagina serves as the receptacle for the penis during intercourse, the passage for menstrual flow, and the birth canal [4](#page=4). #### 1.2.2 Uterus (womb) The uterus is a hollow, muscular, inverted pear-shaped organ located in the pelvic cavity between the bladder and rectum, typically in an anteverted and anteflexed position. It measures approximately 7.5 cm in length, 5 cm in width, and 2.5 cm in thickness, weighing about 30-40 grams. The uterus is divided into the fundus, body, and cervix. Its wall is composed of three layers: the perimetrium (outer layer), myometrium (middle layer), and endometrium (inner layer). The space within the uterus is called the uterine cavity [4](#page=4) [5](#page=5). * **Perimetrium:** The outermost layer, derived from the visceral peritoneum, consists of simple squamous epithelium and areolar connective tissue [5](#page=5). * **Myometrium:** The middle layer is composed of smooth muscle that contracts during childbirth [5](#page=5). * **Endometrium:** The innermost mucous membrane layer, also known as the functional layer, sloughs off during menstruation if fertilization does not occur [5](#page=5). The uterus is supported within the pelvic cavity by adjacent organs, pelvic floor muscles, and ligaments, including the broad ligament, round ligament, uterosacral ligament, and cardinal ligament. The uterus receives blood supply from branches of the internal iliac arteries, anastomosing with the ovarian arteries. It is innervated by autonomic nerves from the sacral parasympathetic nerves and the hypogastric plexus sympathetic nerves [6](#page=6). #### 1.2.3 Fallopian tubes (uterine tubes) There are two fallopian tubes, located laterally to the uterus, connecting it to the ovaries. They open into the uterine cavity and are situated within the broad ligament. Each tube is approximately 10 cm long and has an ampulla (distal portion) and an isthmus (proximal portion). The infundibulum is a funnel-shaped opening at the ovarian end of each tube, surrounded by fimbriae, which are finger-like projections that help direct the secondary oocyte into the tube [6](#page=6). The functions of the fallopian tubes include transporting the secondary oocyte/ovum from the ovary to the uterus. The fimbriae create currents that move the oocyte into the tube, where it is further propelled by cilia and smooth muscle contractions. Fertilization typically occurs within the ampulla of the fallopian tube [7](#page=7). #### 1.2.4 Ovaries The ovaries are the female gonads, located in the lateral walls of the pelvic fossa. They measure approximately 2.5–3.5 cm in length, 2 cm in width, and 1 cm in thickness. The ovaries are attached to the superior uterus by the ovarian ligaments and to the posterior broad ligament via mesovarium tissue. Blood vessels and nerves enter the ovary through the hilum [7](#page=7). The outer surface of the ovary is covered by germinal epithelium, beneath which lie the cortex and medulla [7](#page=7). * **Cortex:** The surrounding layer, composed of connective tissue stroma lined by germinal epithelium [7](#page=7). * **Medulla:** The central part, made up of fibrous connective tissue, blood vessels, and nerves [8](#page=8). Within the cortex are follicles, sac-like structures containing oocytes and surrounding cells that nourish the oocyte and secrete estrogen. These follicles develop into mature Graafian follicles. After ovulation, the follicle transforms into the corpus luteum, which produces progesterone, estrogen, relaxin, and inhibin. The degenerated corpus luteum becomes the corpus albicans, a fibrous tissue [8](#page=8). The ovaries receive arterial and venous blood supply from the ovarian arteries and veins, branches of the abdominal aorta. Lymphatic drainage is via the lateral aortic and pre-aortic lymph nodes. Innervation is supplied by the lumbosacral nerves [8](#page=8). ### 1.3 Physiology of the female reproductive system The primary functions of the female reproductive system include hormone production (estrogen and progesterone), oogenesis (formation of the secondary oocyte), reception of spermatozoa in the vagina, fertilization in the fallopian tubes, and development of the embryo and fetus in the uterus. If fertilization does not occur, the endometrium sheds during menstruation. The uterus contracts to expel the fetus during parturition, with the vagina serving as the birth canal [8](#page=8). --- # Physiology and oogenesis This section outlines the primary functions of the female reproductive system, detailing hormone production, ovum formation (oogenesis), and the hormonal regulation of the ovarian and uterine cycles. ### 2.1 Functions of the female reproductive system The female reproductive system performs several key functions: * **Hormone production:** The oocyte produces estrogen, while the corpus luteum synthesizes progesterone, estrogen (in smaller amounts), relaxin, and inhibin [8](#page=8). * **Ovum/secondary oocyte formation:** Oogenesis is the process of female gamete production [8](#page=8). * **Spermatozoa reception:** The vagina receives spermatozoa [8](#page=8). * **Site of fertilization and fetal development:** Fertilization occurs in the fallopian tube, and the uterus serves as the implantation site for the embryo and the location for fetal development. If fertilization does not occur, menstruation takes place as the endometrium detaches [8](#page=8). * **Parturition (childbirth):** The uterus contracts, and the vagina facilitates the passage of the baby during birth [8](#page=8). ### 2.2 Oogenesis Oogenesis is the process of gamete production in females, which differs from males as it begins before birth in a female fetus. This process involves meiosis and maturation [9](#page=9). #### 2.2.1 Meiosis I * During early fetal development, cells within the ovary differentiate into oogonia, which are diploid ($2n$) [9](#page=9). * Meiosis I commences during fetal development but is not completed until puberty [9](#page=9). * Post-puberty, the anterior pituitary gland secretes gonadotropins, stimulating the resumption of Meiosis I [9](#page=9). * Meiosis I progresses in several primary oocytes ($2n$), although typically only one follicle matures and undergoes ovulation per cycle [9](#page=9). * Upon completion of Meiosis I, each primary oocyte divides into two haploid ($n$) cells of unequal size: a first polar body ($n$) and a secondary oocyte ($n$) [9](#page=9). #### 2.2.2 Meiosis II * The secondary oocyte enters Meiosis II (arresting at metaphase) within the mature Graafian follicle and is then ovulated [9](#page=9). * If fertilization occurs, the secondary oocyte will complete Meiosis II, producing two haploid ($n$) cells: an ovum ($n$) and a second polar body ($n$). The nuclei of the ovum and sperm then fuse to form a diploid zygote ($2n$) [9](#page=9). * Each primary oocyte ultimately yields one secondary oocyte and three polar bodies [9](#page=9). * In contrast to spermatogenesis, which produces four gametes, oogenesis results in the formation of only one ovum [9](#page=9). ### 2.3 Ovarian and uterine cycles Every woman (unless pregnant) typically experiences cyclical changes in her ovaries and uterus. Each cycle lasts approximately one month and involves oogenesis and the uterus preparing to receive a fertilized ovum. Hormones secreted by the hypothalamus, anterior pituitary, and ovaries regulate these cyclical changes [9](#page=9). #### 2.3.1 Ovarian cycle The ovarian cycle is a sequence of events that occur during and after the maturation of an oocyte. It comprises three phases [9](#page=9): A. Follicular phase [9](#page=9). B. Ovulation phase [9](#page=9). C. Luteal phase [9](#page=9). *** **Medulla of the ovary:** The central part of the ovary, composed of fibrous tissue, blood vessels, and nerves [8](#page=8). **Follicle:** A sac-like structure containing an oocyte and surrounding cells that nourish it and secrete estrogen [8](#page=8). **Graafian follicle:** A mature follicle [8](#page=8). **Corpus luteum:** Formed after ovulation from the follicle, it produces progesterone, estrogen, relaxin, and inhibin [8](#page=8). **Corpus albicans:** The degenerated corpus luteum, forming fibrous tissue [8](#page=8). **Blood supply to the ovary:** From the ovarian arteries and veins, which branch from the abdominal aorta [8](#page=8). **Lymphatic drainage:** Via the lateral aortic lymphatic vessels and pre-aortic lymph nodes [8](#page=8). **Nerve supply:** Provided by the lumbosacral nerves [8](#page=8). > **Tip:** Understanding the hormonal regulation of the ovarian and uterine cycles is crucial for comprehending female reproductive health and potential disruptions. Pay close attention to the roles of the hypothalamus, pituitary gland, and the hormones they release. --- # Ovarian and uterine cycles The ovarian and uterine cycles are a series of cyclical changes in the ovaries and uterus, regulated by hormones, that prepare the female reproductive system for potential pregnancy [10](#page=10) [9](#page=9). ### 3.1 Ovarian cycle The ovarian cycle is the sequence of events that occur during and after the maturation of an oocyte. It comprises three main phases: the follicular phase, ovulation, and the luteal phase [9](#page=9). #### 3.1.1 Follicular phase The follicular phase begins with the hypothalamus secreting Gonadotropin-Releasing Hormone (GnRH). GnRH stimulates the anterior pituitary to release Follicle-Stimulating Hormone (FSH). FSH then prompts the development of follicles within the ovary, and concurrently, the oocyte also develops. As the follicles grow, they secrete estrogen, which causes the uterine endometrium to thicken. High levels of estrogen, in turn, stimulate the anterior pituitary to release Luteinizing Hormone (LH), triggering the process of ovulation [10](#page=10). #### 3.1.2 Ovulation phase During ovulation, a mature follicle ruptures, releasing a secondary oocyte (egg). Following ovulation, LH stimulates the remnants of the follicle to form the corpus luteum [10](#page=10). #### 3.1.3 Luteal phase The corpus luteum secretes a large amount of progesterone and a smaller amount of estrogen, leading to further thickening of the uterine endometrium. High levels of progesterone inhibit the production of LH, causing the corpus luteum to degenerate. This degeneration results in a decrease in the secretion of estrogen and progesterone [10](#page=10). ### 3.2 Uterine cycle (Menstrual cycle) The uterine cycle, also known as the menstrual cycle, involves changes in the uterine endometrium to prepare for the implantation and development of a fetus. If fertilization does not occur, the reduction in ovarian hormone secretion leads to the shedding of the thickened endometrium. The uterine cycle is divided into three phases: menstruation, the proliferative phase, and the secretory phase [10](#page=10). #### 3.2.1 Menstruation phase The menstruation phase typically occurs from day 1 to day 5 of the cycle. During this phase, the uterine endometrium sheds, accompanied by a decrease in estrogen and progesterone levels. Blood vessels in the endometrium constrict, reducing blood supply to the tissue, and menstrual blood is expelled [10](#page=10). #### 3.2.2 Proliferative phase The proliferative phase occurs from approximately day 6 to day 14. During this period, the developing follicles secrete estrogen, initiating a phase of repair and thickening of the uterine endometrium [10](#page=10). #### 3.2.3 Secretory phase The secretory phase takes place from day 15 to day 28. The corpus luteum secretes progesterone and some estrogen, further increasing the thickness of the endometrium. Endometrial cells become supplied with glands rich in glucose and mucus secretions, and blood vessels in the endometrial lining increase. The endometrium is now prepared for implantation [11](#page=11). ### 3.3 Mammary glands Mammary glands, also known as breasts, are accessory glands of the female reproductive system. They are located anterior to the pectoralis major muscles and attached to them via fascia. Suspensory ligaments connect the skin and fascia to support the breasts. The amount of adipose tissue surrounding the lobes determines the size of the breasts and contributes to their softness [11](#page=11). --- # Mammary glands and lactation This section details the structure, development, and function of mammary glands, focusing on the hormonal regulation of lactation, milk synthesis, and ejection [11](#page=11) [12](#page=12) [13](#page=13) [14](#page=14). ### 4.1 Structure of mammary glands Mammary glands, also known as breasts, are accessory glands of the female reproductive system. They are situated anterior to the pectoralis major muscles and attached to them by their fascia. Suspensory ligaments connect the skin to the fascia, providing support to the breasts. The size and softness of the breasts are determined by the surrounding adipose tissue [11](#page=11). The nipple is a projection located at the center of the pigmented areola. The nipple contains openings for the lactiferous ducts, through which milk is released. The areola houses numerous sebaceous glands (Montgomery's tubercles) that lubricate the nipple during lactation. Smooth muscle fibers are also present in the nipple [12](#page=12). Mammary glands are composed of three types of tissue: glandular tissue, fibrous tissue, and adipose tissue. Each gland contains approximately 15-20 lobes of glandular tissue, supported and enveloped by fibrous tissue. Each lobe consists of lobules, which contain alveoli arranged in a grapelike cluster extending towards the nipple. The alveolar epithelium synthesizes milk, which is secreted through secondary tubules and then into mammary ducts. These ducts converge to form lactiferous ducts that lead to the nipple. A lactiferous sinus, a dilation beneath the areola, serves as a temporary storage area for milk before it exits through the lactiferous duct openings in the nipple [12](#page=12). > **Tip:** Understanding the layered structure of mammary glands, from lobules to lactiferous sinuses, is crucial for grasping the pathway of milk production and transport [12](#page=12). ### 4.2 Development of mammary glands The development of mammary glands is particularly noticeable in females and occurs during puberty and pregnancy [13](#page=13). #### 4.2.1 Development during puberty During puberty, estrogen stimulates the growth of the ductal system and the connective tissue, as well as capillary proliferation. Fat deposition also increases within the mammary glands. Progesterone, in conjunction with estrogen, stimulates the development of cells surrounding the alveoli, leading to the formation of lobules. Other hormones involved in mammary gland development include growth hormone, cortisol, thyroxine, and insulin. While the mammary glands grow and enlarge during puberty, they are not yet capable of producing milk [13](#page=13). #### 4.2.2 Development during pregnancy During pregnancy, estrogen further promotes the extensive development and branching of the ductal system. The fat content within the mammary glands also increases, providing the building blocks for milk synthesis. Throughout pregnancy, prolactin levels rise, but its effect on milk production is inhibited by progesterone [13](#page=13). ### 4.3 Lactation Lactation refers to the production and ejection of milk by the mammary glands. The synthesis of milk is influenced by prolactin, estrogen, and progesterone, while the ejection of milk is stimulated by oxytocin. Breast milk offers complete nutrition for infants, provides protection against diseases, and reduces the likelihood of allergies [14](#page=14). > **Example:** The hormonal interplay during pregnancy is vital; while prolactin initiates the machinery for milk production, progesterone acts as a brake until after birth [13](#page=13) [14](#page=14). #### 4.3.1 The process of lactation Milk synthesis is carried out by the alveolar epithelium. Once produced, milk travels through secondary tubules into mammary ducts, then collects in the lactiferous sinuses beneath the areola, ready for expulsion [14](#page=14). The ejection of milk is triggered by oxytocin from the posterior pituitary gland, which causes the contraction of myoepithelial cells surrounding the alveoli, forcing milk towards the nipple. This process is controlled by the Milk Ejection Reflex [14](#page=14). During pregnancy, lactation does not occur because progesterone suppresses milk production. Lactation begins after delivery when estrogen and progesterone levels drop, and the anterior pituitary increases prolactin secretion, initiating milk production [14](#page=14). Infant suckling stimulates touch receptors around the nipple, sending impulses to the hypothalamus. The hypothalamus then signals [14](#page=14): * The anterior pituitary to release prolactin, stimulating alveoli for milk secretion [14](#page=14). * The posterior pituitary to release oxytocin, stimulating alveoli for milk ejection into the ducts [14](#page=14). Milk production can continue for 1-2 years if lactation is sustained. Colostrum is the initial yellowish milk produced. Lactation can suppress the ovarian cycle for the first few months postpartum if breastfeeding occurs 8-10 times daily, though this is an unreliable method of birth control. Oxytocin also plays a role in uterine contractions for placental delivery and preventing excessive bleeding [14](#page=14). > **Tip:** The continuous stimulation of suckling is key to maintaining milk supply through the feedback loop involving the hypothalamus, anterior pituitary, and posterior pituitary [14](#page=14). --- ## Common mistakes to avoid - Review all topics thoroughly before exams - Pay attention to formulas and key definitions - Practice with examples provided in each section - Don't memorize without understanding the underlying concepts

| Term | Definition | |------|------------| | Gametes | Specialized reproductive cells produced by males and females; in females, the gamete is the secondary oocyte, and in males, it is the spermatozoon. | | Ovari (Ovary) | The primary female reproductive organ (gonad) responsible for producing female gametes (oocytes) and female sex hormones like estrogen and progesterone. | | Estrogen | A primary female sex hormone produced mainly by the ovaries, responsible for the development and regulation of the female reproductive system and secondary sex characteristics. | | Progesterone | A primary female sex hormone produced mainly by the corpus luteum, which plays a crucial role in the menstrual cycle, pregnancy, and embryogenesis. | | Secondary oocyte | An immature egg cell produced by the ovary; it is arrested in metaphase II of meiosis and will complete meiosis II only if fertilized by a sperm. | | External genitalia | The outer reproductive organs of the female, collectively known as the vulva, which include the mons pubis, labia majora, labia minora, clitoris, vestibule, vaginal orifice, and vestibular glands. | | Internal genitalia | The internal reproductive organs of the female, consisting of the vagina, uterus, fallopian tubes, and ovaries. | | Vagina | A fibromuscular canal that connects the external genitalia to the cervix of the uterus; it serves as the receptacle for the penis during sexual intercourse, the birth canal, and the passageway for menstrual flow. | | Uterus (Womb) | A hollow, muscular organ in the pelvic cavity where a fertilized egg implants and develops into a fetus. It has three layers: the perimetrium, myometrium, and endometrium. | | Fallopian tubes (Uterine tubes) | A pair of tubes that extend from the uterus towards the ovaries, serving as the passageway for the oocyte from the ovary to the uterus and the usual site of fertilization. | | Perineum | The diamond-shaped region between the thighs and buttocks that contains the external reproductive organs and the anus in both males and females. | | Mons Pubis | An elevation of adipose tissue located over the symphysis pubis, covered with pubic hair after puberty. | | Labia Majora | A pair of large, outer folds of skin that form the boundary of the vulva, containing adipose tissue, sebaceous glands, and sudoriferous glands. | | Labia Minora | A pair of smaller, hairless folds of skin located medial to the labia majora, rich in sebaceous glands and converging anteriorly to form the prepuce of the clitoris. | | Clitoris | A small, erectile tissue structure located at the anterior junction of the labia minora, highly sensitive and homologous to the penis in males. | | Vestibule | The area enclosed by the labia minora, containing the urethral orifice anteriorly and the vaginal orifice posteriorly. | | Hymen (Selaput dara) | A thin mucosal membrane that partially covers the vaginal orifice, often with an opening to allow menstrual flow. | | Vestibular Glands | Glands located around the vaginal orifice that secrete mucus to lubricate the vulva. The greater and lesser vestibular glands are distinguished. | | Endometrium | The inner lining of the uterus, a mucous membrane that undergoes cyclical changes during the menstrual cycle, preparing for implantation of a fertilized egg. It sloughs off during menstruation if fertilization does not occur. | | Myometrium | The muscular middle layer of the uterine wall, composed of smooth muscle that contracts during childbirth to expel the fetus. | | Perimetrium | The outer serous layer of the uterine wall, derived from the visceral peritoneum. | | Oogenesis | The process of female gamete (ovum) formation, which begins before birth and involves meiosis and maturation. | | Meiosis | A type of cell division that reduces the chromosome number by half, producing gametes (sperm and eggs) for sexual reproduction. | | Polar body | Small, non-functional cells produced during meiosis in oogenesis. The first polar body is produced after Meiosis I, and the second polar body is produced after Meiosis II. | | Ovulation | The release of a mature secondary oocyte from the ovary, typically occurring once per menstrual cycle. | | Corpus Luteum | A temporary endocrine structure formed in the ovary after ovulation from the remnants of the ovarian follicle. It produces progesterone and estrogen. | | Corpus Albicans | A regressed corpus luteum that degenerates into a fibrous scar tissue. | | Follicle | A sac-like structure within the ovary that contains an oocyte and surrounding cells that nourish the oocyte and secrete hormones, primarily estrogen. | | Graafian follicle | A mature ovarian follicle that is ready to ovulate. | | GnRH (Gonadotropin-releasing hormone) | A hormone released by the hypothalamus that stimulates the anterior pituitary to secrete FSH and LH. | | FSH (Follicle-stimulating hormone) | A hormone secreted by the anterior pituitary that stimulates the development of ovarian follicles and oocytes. | | LH (Luteinizing hormone) | A hormone secreted by the anterior pituitary that triggers ovulation and the formation of the corpus luteum. | | Menstrual cycle (Kitar Haid) | The monthly cyclical changes in the female reproductive system, specifically the changes in the endometrium, preparing for potential pregnancy or leading to menstruation. | | Menstruation (Fasa Haid) | The shedding of the uterine lining (endometrium) accompanied by bleeding, occurring if fertilization does not take place. | | Proliferation phase (Fasa Proliferasi) | The phase of the uterine cycle (days 6-14) where the endometrium regenerates and thickens under the influence of estrogen. | | Secretion phase (Fasa Rembesan) | The phase of the uterine cycle (days 15-28) where the endometrium becomes highly vascularized and glandular, producing secretions under the influence of progesterone, preparing for implantation. | | Mammary glands (Kelenjar Mamari) | Accessory glands of the female reproductive system located on the chest, responsible for the synthesis, secretion, and ejection of milk (lactation) to nourish a newborn infant. | | Lactation | The production and secretion of milk by the mammary glands following childbirth. | | Prolactin | A hormone secreted by the anterior pituitary that stimulates milk production (synthesis) in the mammary glands. | | Oxytocin | A hormone released by the posterior pituitary that stimulates uterine contractions during childbirth and the ejection of milk during lactation. | | Suckling | The act of an infant feeding from the breast, which stimulates a reflex that leads to the release of prolactin and oxytocin, promoting milk production and ejection. | | Colostrum | The first milk produced by the mammary glands after childbirth, which is yellowish and rich in antibodies and nutrients beneficial for the newborn. |