Reproductive System Pt.2 Flashcards
Female reproductive system
■ Produces sex hormones and functional gametes
■ Protects and supports developing embryo
■ Nourishes newborn
Ovaries
■ Are small, almond-shaped organs:
- near posterior walls of pelvic cavity
- 5 cm long, 2.5 cm wide, 8mm thick
-weigh 6–8 g
Ovaries held in position by
Ovarian and suspensory ligaments of mesovaria
Ovaries contains what type of follicle
Oocyte-containing follicles
3 fictions of ovaries
■ Production of immature female gametes (oocytes)
■ Secretion of female sex hormones (estrogens, progestins)
■ Secretion of inhibin:
-feedback control of pituitary FSH
Stroma
■ Are interior tissues of ovary:
-superficial cortex
-deeper medulla
■ Gametes are produced in ovaries
Uterine tube
-supported by mesosalpinx
-extends from near ovary to uterus
-movements of its ciliated distal projections (fimbriae) along w/ peristalsis creates currents to help move ovulated locate in the uterine tube
Uterine wall composed of:
-outer perimetrium
-myometrium
-inner endometrium
Endometrium consists of:
-functional layer (stratum functionalis)
-sloughs off periodically unless an embryo has implanted
-underlying basal layer (stratum basalis)
-rebuilds functional layer
Vagina
-extends from uterus to exterior
-copulatory organ
-allows passage of menstrual flow or baby
Oogenesis
■ Also called ovum production
■ Begins before birth
■ Accelerates at puberty
■ Ends at menopause
Atresia
■ Is the degeneration of primordial follicles:
■ Ovaries have about 2 million primordial follicles at birth:
-each containing a primary oocyte
■ By puberty:
-number drops to about 40,000
Why are women more at risk for pid than men?
B/c duct system of women is incomplete- there is no physical connection between ovary and uterine tubes, which are open to the pelvic cavity.
In men, duct system is continuous from testes to body exterior
Process of oogenesis
■ Primary oocytes remain in suspended development until puberty
■ At puberty:
-rising FSH triggers start of ovarian cycle
■ Each month thereafter:
-some primary oocytes are stimulated to mature further during menstrual cycle
Oogenesis: 2 characteristics of meiosis
■ Cytoplasm of primary oocyte divides unevenly:
-producing 1 ovum (with original cytoplasm)
-and 2 or 3 polar bodies (that disintegrate)
■ Ovary releases secondary oocyte (not mature ovum):
-suspended in metaphase of meiosis II
Locates are ovulated into the peritoneal cavity and yet women do get pregnant. What action if the uterine tubes helps to direct locates into woman’s duct system?
Waving action of fimbriae and currents created by beating cilia help to direct ovulated locates into uterine tube
Ovarian follicles
■ Are specialized structures in cortex of ovaries:
-where oocyte growth and meiosis I occur
Primary oocytes
■ Are located in outer part of ovarian cortex:
-near tunica albuginea
-in clusters called egg nests
Primordial follicle
■ Each primary oocyte in an egg nest:
-is surrounded by 1 layer of follicle cells
■ immature oocyte and follicle cells form a primordial follicle (1 year before ovulation)
-different group of primordial follicles are activated each mo
Vulva (fem genitalia) include:
-Mons pubis
-labia majors and minora
-clitoris
-urethral and vagina orficies
Ovarian cycle: step 1
■ Formation of primary follicles:
-pre-granulosa cells become granulosa cells when multiple layers develop
Zona Pellucida
■ Region surrounding primary oocyte
■ Contains microvilli and glycoproteins
Thecal Cells
■ Surround follicle
■ Work with granulosa cells to produce estrogens
The Ovarian Cycle: Step 1
• Formation of primary follicles:
o follicle cells become granulosa cells when multiple layers develop
What is female homologous of bulbo-urethral glands of males?
Greater vestibular glands
Ovarian cycle: step 2
■ Formation of secondary follicles
■ Follicular fluid:
-accumulates between inner and outer layers of
follicle
Ovarian cycle: step 3
■ Formation of a tertiary (mature Graafian) follicle:
-primary oocyte produces secondary oocyte and polar body
■ Secondary oocyte drifts free in antrum (expanded central chamber of follicle)
Corona Radiata
■ Granulosa cells associated with secondary oocyte
Cite similarities and differences between penis and citoris.
Both hooded by skin fold and are largely erectile tissue
Clitoris lacks corpus spongiosum containing urethra, so urinary and reproductive systems are completely separated in females
Tissues surrounding mammary glands
Adipose and fibrous connective tissue
Ovarian cycle: step 4
■ At ovulation:
■ tertiary follicle releases secondary oocyte with its corona radiata to peritoneal cavity
■ What remains is called the Corpus Hemorrhagicum
-It develops into the Corpus Luteum
Ovarian cycle: step 5
■ Formation of corpus luteum:
-produces steroid hormones progestins (progesterone) and some estrogen from cholesterol
■ Progesterone prepares uterine lining for pregnancy
Developmentally, mammary glands are modifications of certain skin glands. Which type?
Sweat glands
When does the glandular portion of breast develop in females?
Midway through pregnancy
Ovarian cycle: step 6
■ If fertilization does not occur
■ corpus luteum:
▪ degenerates about 14 days after ovulation
▪ fills with scar tissue to become corpus albicans
Uterine tubes
■ Fallopian tubes or oviducts
■ Are hollow, muscular tubes about 13 cm long
■ Transport oocyte from ovary to uterus
3 Segments of the Uterine Tube
■ Infundibulum:
-an expanded funnel near ovary
-fimbriae extend into pelvic cavity
■ Inner surfaces lined with cilia:
-beat toward infundibulum segment
3 segments of uterine tube
1.Ampulla:
-middle and longest segment
-smooth muscle layers in wall become thicker approaching uterus
2.Isthmus:
-a short segment between ampulla and uterine wall
3.infundibulum
Uterine tube structure
■ Epithelium lining uterine tube:
-contains scattered mucin secreting cells
■ Mucosa is surrounded by concentric layers of muscle
Oogenesis
Production of eggs
Begins in fetus
Oogonia
-Diploid stem cells that give rise to female gametes
-converted to oocytes before birth
Uterine tube and oocyte transport
■ Involves:
-ciliary movement
-peristaltic contractions in walls of uterine tube
-These processes are turned on by the ANS shortly before ovulation
■ It usually takes 3-4 days for the egg to reach the uterus
Meiosis
-puberty: meiosis resumes
-each mo, 1 primary oocyte completes meiosis I, producing secondary oocyte and tiny 1st polar body
-meiosis II or secondary oocyte produces functional ovum and 2nd polar body, but does not occur in less sperm penetrates secondary oocyte
-ovum contains most of primary oocytes cytoplasm. Polar bodies are nonfunctional and degenerate
Spermatogenesis vs Oogenesis
1 egg
4 sperm cells
Uterine tube and fertilization
■ For fertilization to occur:
-secondary oocyte must meet spermatozoa during first 12–24 hours – egg viable for 24hrs
■ Fertilization typically occurs:
-near boundary between ampulla and isthmus
Unfertilized oocytes
■ Degenerate in terminal portions of uterine tubes:
-or within uterus
Uterus
■ Provides for developing embryo (weeks 1–8) and fetus (week 9 through delivery):
-mechanical protection
-nutritional support
-waste removal
■ Is pear-shaped:
-7.5 cm long, 5 cm diameter
-weighs 30–40 g
■ Normally bends anteriorly near base (anteflexion):
-in retroflexion, uterus bends backward (20% incidence; no significance)
How do haploid cells arising from Oogenesis differ structurally and functionally from those arising from spermatogenesis.
Products of meiosis in females are 2 or 3 nonfunctional polar bodies (tiny haploid cells w/ essentially no cytoplasm) and 1 haploid ovum (functional gamete)
Meiosis in males yield 4 functional gametes, haploid sperm
3 suspensory ligaments of uterus
■ Uterosacral ligaments:
-extend from uterus to sacrum
-prevent inferior–anterior movement
■ Round ligaments:
-extend through inguinal canal
-end in connective tissues of external genitalia
-restrict posterior movement
■ Lateral (cardinal) ligaments:
-extend from base of uterus and vagina
-to lateral walls of pelvis
-prevent inferior movement
2 regions of uterus
■ Body
■ Cervix
The Uterine Body
■ Also called corpus
■ Is largest portion of uterus
■ Ends at isthmus
The Fundus
■ Is rounded portion of uterine body:
-superior to attachment of uterine tubes
What name is given to fluid-filled cavity of a vestibular follicle?
Antrum
The cervix
■ Is inferior portion of uterus
■ Extends from isthmus to vagina
■ Distal end projects about 1.25 cm into vagina
The Cervical Os
■ Also called external orifice of uterus
■ Is surrounded by distal end of cervix
■ Leads into cervical canal
The Cervical Canal
■ Is a constricted passageway opening to uterine cavity of body:
-at internal os (internal orifice)
Follicular phase of ovarian cycle
-1-14 days
-several vesicular follicles are rescued from atresia and continue to grow.
-only 1 per mo is selected to become
dominant follicle and completes maturation process
-late in this phase, oocyte in the dominant follicle completes meiosis I
-ovulation occurs about day 14, releasing secondary oocyte into peritoneal cavity, other developing follicles deteriorate
Cervical cancer
▪ 50,000 women/yr worldwide– killing half
▪ Most common between 30 – 50
▪ Risks – frequent cervical inflammations, STIs, multiple pregnancies
▪ Papanicolaou (Pap) smear for detection
-Every two years 21 – 30; every year > 30; discontinue at 65 if negative for 10 years
▪ Pap smear results inconclusive
-Test for human papillomavirus – cause of most cervical cancers
▪ Gardasil – three-dose vaccine; protects against HPV
-Recommended for 11- and 12-year-old girls
Blood supply of uterus
■ ranches of uterine arteries:
-arising from branches of internal iliac arteries
■ Ovarian arteries:
-arising from abdominal aorta
■ Veins and lymphatic vessels
Nerves of the Uterus
■ Autonomic fibers from hypogastric plexus (sympathetic)
■ Sacral segments S3 and S4 (parasympathetic)
■ Segmental blocks:
-anesthetic procedure used during labor
-target spinal nerves T10–L1
Literal phase of ovarian cycle
-ruptured follicle is converted to a corpus luteum, which produces progesterone and estrogens for the remainder of the cycle
-if fertilization does not occur, corpus luteum degenerated after about 10 days