Page 225 - Physiology and Pathophysiology MNU 2024-2025 نظرى

Clinical pharmacy 2024/2025 Level 2 Pharm D Physiology and Pathophysiology (MD303)
Ovarian cycle:

Follicular • 1ry result→ a mature Graafian follicle and 2ry oocyte, Duration ≈14 days :
• dominated by 17β-estradiol, Estrogens gradually  ➔ causing FSH and LH
to peak & progesterone remains low throughout

14:28 day
ovulation Luteal: secretory

✓ Ovulation follows a burst of estradiol ✓ Corpus luteum develops and begins
secretion at the end of the follicular synthesizing estradiol and progesterone.

phase: ✓ progesterone during this phase ➔ stimulate
✓ The burst of estradiol has a positive secretory activity of the endometrium, its
feedback effect on FSH and LH vascularity. Progesterone is preparing the

secretion by the anterior pituitary endometrium to receive a fertilized ovum.
(called the FSH and LH surge). ✓ Basal body temperature because

✓ The FSH and LH surge then causes progesterone increases the hypothalamic
ovulation of the mature ovum. temperature set-point.
✓ At ovulation, cervical mucus ✓ The cervical mucus becomes less abundant

increases in quantity and becomes and thicker, and it is now "too late" for
watery and more penetrable by sperm to fertilize the ovum.

sperm. ✓ if fertilization has not occurred, the corpus
✓ Estradiol levels decrease just after luteum regresses. With this regression, the
ovulation, but they will increase luteal source of estradiol and progesterone

again during the luteal phase. is lost, and blood levels of the hormones

decrease abruptly.
Menses: 4 to 5 days

 Regression of the corpus luteum and the abrupt loss of estradiol and progesterone
cause the endometrial lining and blood to be sloughed (menses or menstrual bleeding).

 During this time, primordial follicles for the next cycle are being recruited and are
beginning to develop.

Pregnancy

Early days

0 day Day 1 Day 4 Day 5 Day 6 8-10
Ovulation Fertilization Entrance of Implantation Formation of HCG
blastocyst into trophoblast and
uterine cavity attachment to
endometrium

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