Lect 28: uterine cycle

Question 1

endometrial (uterine) cycle consists of what 3 phases

Answer 1

1. menstrual phase: 0-4 d
2. proliferative phase: 5-14 d
3. secretory (progestational) phase: days 15-28

Question 2

describe uterine cycle: menstual phase

• when does it occur
• where does it link with ovarian cycle

Answer 2

• discharge of blood and endometrial debris from vagina
• first day of menstruation marks new cycle
• menses occurs 14 days after ovulation
• coincides with end of ovarian luteal phase

Question 3

function of release of prostaglandins during menstrual phase

Answer 3

• causes vasoconstriction of endometrial vessels which disrupts blood supply and results in death of endometrium
• stimulates mild contractions of uterium myometrium which helps expel blood and debris into vagina

Question 4

Proliferative phase in dominated by what hormone

Answer 4

• estrogen

Question 5

describe proliferative phase

• where does it link with ovarian cycle
• what is occuring

Answer 5

• begins with last portion of ovarian follicular phase: lasts from end of menstruation to ovulation
• endometrium starts to repair itself and proliferate under influence of estrogen from newly growing follicles
• peak estrogen levels trigger LH surge -> ovulation

Question 6

When does uterus enter secretory/progestational phase

Answer 6

after ovulation when new corpus luteum is formed

Question 7

what is occuring during secretory/progestational phase

Answer 7

• progesterone secreted from corpus luteum converts endometrium to highly vascularized, glycogen-filled tissue
• endometrial glands actively secrete glycogen

Question 8

what happens during secretory/progestational phase if fertilization and implantation do not occur

Answer 8

• corpus luteum degenerates
• new follicular phase and menstrual phase begin once again

Question 9

effects of estrogen on fallopian tubes

Answer 9

increases number of cilia and thier rate of beating, drawing the ovum into the tube

Question 10

effects of estrogen on myometrium

Answer 10

increases oxytocin receptors and contractions

Question 11

effects of estrogen on endometrium

Answer 11

• thickens, increases permeability and blood supply
• synthesizes receptors for progesterone on uterine cells

Question 12

effects of estrogen on cervix and vagina

Answer 12

• cervix: makes environment more alklaline and watery and increases distensibility, making birthing easier
• vagina: increases vaginal secretions

Question 13

effects of estrogen on mammary glands

Answer 13

• required for growth

Question 14

effects of estrogen on skeletal system/Ca2+ metabolism

Answer 14

• facilitates calcium uptake into bone
• antagonizes PTH

Question 15

effects of estrogen on skin

Answer 15

• inhibits body and facial hair growth
• promotes pubic and axillary hair growth

Question 16

effects of estrogen on kidney electrolytes

Answer 16

• increases absorption of Na, Cl-, and H2O, contributes to bloating

Question 17

Effects of Progesterone on Uterus

Answer 17

• needs estrogen prior to stimulation
• increases development, differentiation of endometrial glands, converts uterus into actively secreting tissue
• induces placenta formation
• decreases contractility

Question 18

Effects of Progesterone on cervix and vagina

Answer 18

• antagonizes estrogen!
• cervix
  
  • decreases distensibility
  • thick, acidic, mucus, poor environment for sperm
• vagina
  
  • decreases proliferation of epithelial layer

Question 19

Effects of Progesterone on mammary gland

Answer 19

increases branching of ductal system

Question 20

Effects of Progesterone on body temp

Answer 20

increases temp following ovulation and increases appetite

Question 21

Effects of Progesterone on kidney electrolytes

Answer 21

decreases Na+ reabsorption

Question 22

which hormone is responsible for growth and development of vagina, uterus, and oviducts: organs essential to ovum transport and zygote implantations

Answer 22

estrogen

Question 23

which hormone is the hormone of pregnancy responsible for implantation of zygote and maintenance of pregnancy state

Answer 23

progesterone

• acts on estrogen primed tissues and typically antagonizes estrogen’s effects

Question 24

PMDD

Answer 24

premenstrual dysmorphic disorder

Question 25

when does menopause typically occur ? what triggers onset

Answer 25

45-55, hypothalamic changes may trigger onset

Question 26

period of transition through menopause is called

Answer 26

climacteric

Question 27

what is menopause

Answer 27

* decline in fertility associated with a decline in ovarian function * related to a drop in critical mass of primordial follicles

Question 28

Primary cause of perimenopause is a decrease in follicular pool. What are the next steps

Answer 28

1. inhibin decreases -\> FSH increases -\> acceleration of follicular maturation -\> shorter cycle

Question 29

What happens in perimenopause when the follicular pool decreases even further?

Answer 29

* E2 (estradiol (E2) decreses -\> delayed + feedback -\> longer cycle * insufficient E2 -\> no + feedback -\> anovulatory

Question 30

What happens in menopause when the follicular pool decreases even further?

Answer 30

* E2 very low -\> LH and FSH high * cycle arrest

Question 31

when is menopause diagnosed

Answer 31

* _FSH \> 30 mIU/ml_ * no menses for 12 months in women of typical age range

Question 32

What is ERT and when is it used

Answer 32

* estrogen only * used if woman has had hysterectomy

Question 33

What is HRT and when is it used

Answer 33

* estrogen + progesterone * typical treatment * progesterone opposes estrogen effects on uterus

Question 34

MOA of progesterone only oral contraceptive pills

Answer 34

* prevent ovulation by negative feedback on the anterior pituitary, preventing LH surge * thickening of cervical mucus which reduces sperm motility * decreased uterine glycogen production, which impairs blastocyts survival and interferes with implantation

Question 35

MOA of Plan B

Answer 35

* high dose combination of estrogen + progesterone * suppress ovulation * premature degeneration of corput luteum