Uterine Internal Anatomy

1
Uterine Internal Anatomy

• Fundus
• Body
• Cervix (neck)
• Into vagina
• Uterine cavity
• Mucus filling cervical canal covers external
  orifice
• Thin/watery when ovulation occurs (part of
  cervical cycle)

Fig 27.15
2
Uterine Ligaments

• Uterosacral lat uterus to ant sacrum
• Body not move inferior or anteriorly
• Round lat uterus inf to base of Fallopians, pass
  anteriorly through inguinal canal and end in
  labia majora
• Restrict post movement
• Lateral base of uterus and vagina to lat pelvis
• Prevent inf movement
• Pelvic diaphragm below

Fig 27.15
3
Uterine Wall

• Outer to inner
• Perimetrium
• Myometrium
• Myo muscle metra uterus
• Smooth muscle
• Endometrium
• Glandular and vascular
• Estrogen changes these during phases of uterine
  cycle

Fig 27.16 b
4
Histology of Uterus

• Functional zone
• Uterine glands, most of endometrial thickness
• Spiral aa
• Basilar zone
• Endometrium attachment to myometrium
• Terminal branches of glands
• Straight aa
• Basilar remains constant functional changes
  during uterine cycle

5
Uterine/Menstrual Cycle

• 28 days (21-35)
• Menses
• Proliferative phase
• Secretory phase

6
Menses

• Progestin and estrogen decrease at end of ovarian
  cycle
• Destruction of functional zone
• Aa constrict ? reduce blood
• Glands and tissues die
• Blood vessels rupture
• Functional zone, blood, tissue lost through
  vagina
• Called menstruation
• 1-7 days

7
Proliferative Phase

• Glands in basal zone remain
• Estrogen from developing follicles causes glands
  to increase in all along endometrial surface
• More growth and vascularization complete
  functional zone
• Highly vascularized spiral arteries, lots of
  mucus
• Occurs at same time as 1 and 2 follicles enlarge

8
Secretory Phase

• Progestins and estrogens from corpus luteum
• Endometrial glands enlarge
• Arteries spiral through entire functional zone
• Begins at ovulation, stays as long as CL is
  maintained
• Lasts 14 days
• Peaks 12 days after ovulation
• Gland activity declines, uterine cycle ends when
  CL stops making progestins and extrogen
• Menstruation

9
Vagina

• Elastic, muscular tube b/n rectum and urethra
• Cervix ? vestibule of external genitalia
• Cervix projects into vaginal canal
• Area surrounding fornix
• Passage for menstruation
• Receives penis during intercourse holds
  spermatozoa before passing to uterus
• Last part fetus delivered through during
  childbirth
• Resident bacteria acid environment (buffers from
  prostate gland important)

Fig 27.20 b
10
External Genitalia

• Labia minora boundary of vestibule
• Hairless urethra opens just ant to vaginal
  orifice
• Clitoris projects into vestibule
• Erectile tissue similar to corpora cavernosa
• Becomes engorged w/blood during sexual arousal
• Labia majora around labia minora
• Mons pubis sup to clitoris

11
Mammary Glands

• Milk production and secretion (lactation)
• Nipple ducts open to surface
• Areola reddish-brown skin surrounding
• Sebaceous glands in lobes and lobules
• Ducts ? lactiferous duct ? lactiferous sinus
  (expanded chamber)
• Suspensory ligaments
• Non-lactating mostly ducts
• Pregnant prolactin and growth hormone human
  placental lactogen ducts to be active
• Suckling oxytocin release milk let-down

Fig 27.21
12
Pregnancy

• Fertilization zygote formed ? blastocyst (hollow
  ball of cells)
• Buries itself in endometrium (implantation)
• Placenta will be formed to support embryonic and
  fetal development
• Dissolved gases, nutrients, wastes
• Human chorionic gonadotropin (HCG)
• CL not disintegrate (if did, functional zone
  would be lost)
• Relaxin increase pelvic flexibility cervical
  dilation
• Human placental lactogen milk production