Flashcards in Chapter 5 - Anatomy & Physiology - Module 1 Deck (52):
The pelvis is composed of:
The pelvis is composed of: (1) two hip bones called the innominate bones (ox coxae); (2) the sacrum; and (3) the coccyx.
The innominate bones consist of
The innominate bones consist of the pubis, the ischium, and the ilium, all of which fuse at the acetabulum.
Pelvic support structures include not only the muscles and connective tissue of the pelvic floor, but also the fibromuscular tissue of the vaginal wall and endoplevic connective tissue.
Levator ani muscle
The levator ani muscle is a critical component of pelvic support; is it often considered the most important muscle of the pelvic floor. Normally it is in a constant state of contraction, providing support for all of the abdominopelvic contents against intra-abdominal pressures.
The vulva is the externally visible outer genitalia. It includes the:
- mons pubis
- labia minora and majora
- urinary meatus
- vaginal opening
- corpus spongiosum erectile tissue (vestibular bulbs)
Located on each side of the vestibule, Bartholin's glands secrete lubricating mucus into the introitus during sexual excitement. Bartholin's glands are pea sized and are located at about the 4 and 8 o'clock positions in the vulvovaginal area, just beneath the fascia. The opening is between the labia minora and the hymen.
The mons pubis is the mound-like fatty tissue that covers and protects the symphysis pubis. During puberty, genital hair growth covers this pad of tissue
The labia majora assist in keeping the vaginal introitus closed, which, in turn, helps prevent infection.
The labia minora are surrounded by the labia majora and are smaller, non-fatty folds covered by non-hair-bearing skin laterally and by vaginal mucosa on the medial aspect. The labia minora also assist in enclosing the opening of the urethra and the vagina. Labia minora are usually more prominent in children and postmenopausal women.
The clitoris is a sensitive organ that is typically described as the female homologue of the penis in the male, particularly in its erogenous function.
Skene's (paraurethral) glands
Two Skene's (paraurethral) glands open directly into the vulva and are adjacent to the distal urethra. The Skene's glands, which release mucus, form a triangular area of mucous membrane surrounding the urethral meatus from the clitoral glans to the vaginal upper rim or caruncle.
Skene's glands release mucus.
The urethra is a short conduit, approximately 3 - 5 cm long, extending from the base of the bladder and exiting externally in the periurethral glans area.
Ovaries, located near the lateral walls of the pelvic cavity, produce gametes (ova) and the sex hormones estrogen and progesterone.
Fallopian tubes, oviducts, are paired narrow muscular tubes that extend approximately 10 cm from each cornu of the body of the uterus, outward to their openings near the ovaries. Often the site of fertilization. Transfer the ova from the ovaries to the uterus.
The uterus is a muscular, inverted, pear-shaped, hollow, thick -walled organ that opens to the vagina at the cervix and then widens toward the top where the uterine tubes enter. Its anatomic regions include the fundus, body, and cervix.
The vagina is a thin-walled tube extending from the external vulva to the cervix.
The cervix is the lower portion of the uterus that opens into the vagina. It is made mostly of dense connective tissue. The opening of the cervix into the vagina occurs at almost a right angle to the long axis of the vagina.
Breasts often define women in both the public and private eye.
Breasts are large, modified sebaceous glands contained within the superficial fascia of the chest wall located over the pectoral muscles. 15 - 20 lobes branch to form 20 - 40 lobules which are subdivided into many secretory alveoli. Alveoli produce milk and other substances during lactation.
The areola is the pigmented area surrounding the nipple. The areola is populated by numerous oil-producing Montgomery's glands whose purpose is to protect and lubricate the nipple during lactation.
Prolactin (PRL) and growth hormone (GH) and breast development
Prolactin (PRL) and growth hormone (GH) from the anterior lobe of the pituitary stimulate mammary gland development.
Human placental lactogen
Human placental lactogen from the placenta and prolactin and growth hormone stimulate the mammary gland ducts to become active during pregnancy.
Estrogen promotes the growth of the gland and ducts.
Progesterone stimulates the development of milk-producing cells.
Prolactin, released from the anterior pituitary, stimulates milk production.
Oxytocin, released from the posterior pituitary in response to suckling, causes milk ejection.
Menarche is the first menstrual cycle and is the most readily evident external event that indicates the end of one developmental stage and the beginning of another. Often irregular during first 18 months d/t the immaturity of the hypothalamic-pituitary-ovarian axes.
"Normal" menstrual cycle parameters
Cycle: 21 - 35 days
Flow: 4 - 6 days
Volume: 20 mL - 80 mL, average = 50 mL
Woman who has not given birth.
A woman who has given birth at least once.
A woman who has given birth at least twice.
The hypothalamus controls anterior pituitary functions via the secretion of releasing and inhibiting factors. Together with the pituitary, it manages the production of hormones that serve as chemical messengers for the regulation of the gynecologic system.
Gonadotropin-releasing hormone (GnRH)
Released by the hypothalamus, gonadotropin-releasing hormone (GnRH) stimulates the pituitary gland to produce follicle-stimulating hormone (FSH) and luteinizing hormone (LH). GnRH is released Q 90 minutes during the early follicular phased, increasing to Q 60 - 70 minutes, then decreasing during the luteal phase.
Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) stimulate
FSH and LH stimulate estrogen and progesterone secretion by the ovaries.
The pituitary gland, an oval-shaped, pea-sized gland, is located in a small depression in the sphenoid bone of the skull. It is controlled by the hypothalamus, which secretes releasing factors into a special blood vessel network called the hypothalamic-hypophyseal portal system.
The anterior pituitary synthesizes 7 hormones
The anterior pituitary synthesizes:
- Growth hormone (GH)
- Thyroid-stimulating hormone (TSH)
- Adrenocorticotropin (ACTH)
- Melanocyte-stimulating hormone (MSH)
- Prolactin (PRL)
- Follicle-stimulating hormone (FSH)
- Luteinizing hormone (LH)
FSH and LH, both gonadotropins, are responsible for regulating gynecologic organ activities.
Follicle-stimulating hormone (FSH)
FSH targets the ovaries, where it stimulates the growth and development of the primary follicles and results in the production of estrogen and progesterone.
Luteinizing hormone (LH)
LH targets the developing follicle within the ovary. LH is responsible for ovulation, corpus luteum formation, and hormone production in the ovaries.
Prolactin is responsible for preparing the mammary gland for lactation and brings about the synthesis of milk.
Ovarian cycle objective
The objective of the ovarian cycle is to produce an ovum.
Endometrial cycle objective
The objective of the endometrial cycle is to prepare a site to nourish and maintain the ovum if fertilized.
Ovarian cycle phases (3)
The three phases of the ovarian cycle are:
- Follicular phase
- Ovulation phase
- Luteal phase
Endometrial cycle phases (3)
The two phases of the endometrial cycle are:
- Proliferative phase
- Secretory phase
Ovarian cycle, Follicular Phase
The follicular phase is characterized by the development of ovarian follicles. Day 1 - 14. Day 1 is first day of menses. Folliculogenesis begins during the last few days of the previous menstrual cycle and continues until the release of the mature follicle at ovulation.
The role of FSH, primarily, is to induce the development of increased receptors on the granulosa cells to produce estrogen.
Ovarian cycle, Ovulatory Phase
Ovulation is the process whereby the mature ovum is released from the follicle. Occurs about 10 - 12 hours after the LH peak. Ovulation and the subsequent conversion of the follicle to the corpus luteum are dependent on an increased level of estrogen and the LH surge. The LH surge begins 34 - 36 hours prior to ovulation and provides a relatively accurate predictor for timing ovulation.
Ovarian cycle, Luteal Phase
The formation of the corpus luteum which continues to function for about 8 days after ovulation. The corpus luteum secretes increased progesterone and some estrogen that start the negative feedback loop to the hypothalamus and pituitary gland, preventing further ovulation within the current cycle.
Endometrial Cycle, Proliferative Phase
Influenced by estrogen and entailing the regrowth of the endometrium after the menstrual bleed. Starts around the 4th or 5th day of the cycles, lasts about 10 days, ending with ovulation. Progressive mitotic growth of the deciduas functionalis in response to increasing levels of estrogen secreted by the ovary occurs. Preparation of implantation of the fertilized ovum.
Endometrial Cycle, Secretory Phase
Begins at ovulation, from day 15 til the end. Most constant phase, in terms of time. If ovulation doesn't happen, nor does this phase.
During the secretory phase, the glands of the endometrium become more tortuous and dilated and fill with secretions, primarily as a result of increased progesterone production. The endometrium becomes thick, cushiony, and nutritive in preparation for implantation. If no implantation, corpus luteum shrinks, and progesterone and estrogen levels subsequently fall.
Currently, it is thought that initiation of menstruation is due to enzymatic autodigestion of the functional layer of the endometrium, triggered by estrogen-progesterone withdrawal.
Endometrial Cycle, Menstrual Phase
Begins with the initiation of menses and lasts 4 - 6 days. Prostaglandins initiate contractions of the uterine smooth muscle and sloughing of the degraded endometrial tissue, leading to menstruation. Menstrual blood does not clot b/c clotting factors are lysed by lysosomal enzymes in the uterus. Lasts 3 - 5, on average, with 20 - 80 mL of blood loss.
Estrogen stimulation of regeneration occurs while concurrent simultaneous endometrial shedding is occurring.
Cervix, cyclic changes
After menstruation: cervical mucus is scant and viscous.
During the late follicular phase, cervical mucus is clear, copious, and elastic. Cervical mucus is clear and stretchable. Ferning appearance during the ovulatory period if observed under the microscope.
After ovulation, progesterone levels are high, cervical mucus once again becomes thick, viscous, opaque, and decreased in amount. This is hostile mucus and impenetrable to sperm Increased viscosity reduces the risk of ascending infections at the time of implantation.