Luteal Exam

Question 1

Luteal Duration

Answer 1

Starts immediately after ovulation and goes until CL regresses
metestrus and diestrus

Question 2

3 Phases

Answer 2

CL formation (luteinization governed by LH)
Steroid Production (P4)
CL Regression (loses ability to produce P4)

Question 3

Preovulatory Follicle + Basement

Answer 3

basement membrane separates theca and gran cells but collagenase degrades so they begin to mix

Question 4

Corpus Hemorrhagicum
During Ovulation

Answer 4

-Follicle ruptures during ovulation
-Blood vessels within in the follicle wall rupture: bloody clot on ovary that prevents cells from leaving the ovary

Question 5

Corpus Hemorrhagicum after ovulation

Answer 5

• collapsed follicle wall creates many folds
  gran and theca cells mix uniformly (humans and primates are exception to this)
  -Deteriorating basmement membrane makes CL connective tissue

Question 6

Luteinization

Answer 6

process where cells of ovulatory follicle are transformed into luteal tissue

Question 7

Gran Cells become . . .

Answer 7

Large Luteal Cells
in cycle secrete oxytocin
in pregnancy secrete relaxin

Question 8

Theca cells become . . .

Answer 8

Small Luteal Cells
-weird shape with lipid droplets
-large and small both secrete P4

Question 9

Large Luteal Cells

Answer 9

rarely multiply after ovulation
hypertrophy (size incr)
CL function associated

Question 10

Small Luteal Cells

Answer 10

Hyperplasia (incr # cells)
Net effect CL enlargement

Question 11

Fxnl Status of CL

Answer 11

Manual Palpation
Blood Concentration of P4 (MOST RELIABLE)
Ultrasonography- diameter of CL closely related to P4 blood [ ]

Question 12

Luteolytic Agent

Answer 12

PGF2a- this can induce etsrus and ovulation

Question 13

Vigor of CL

Answer 13

fxnl capabilities
-ability to secrete P4
depends on # of luteal cells
-deends on vascularization (follic fluid) (ability to make and deliver hormones)

Question 14

P4 Target Organs

Answer 14

Hypothalamus
Uterus
-glandular endometrium
-myometrium
Mammary Glands

Question 15

P4 Stimulatory functions

Answer 15

Uterus-
stimulates maximal secretion by endo
creates envt suitable for free floating conceptus
Mammary-
promotes milk dvpmt

Question 16

P4 Inhibitory Functions

Answer 16

Hypothalamus
reduces basal GnRH
prevents estrus behavior
stops LH surge (- feedback loop)
inhibits myometrium contractions

Question 17

Progesterone synthesis requires

Answer 17

Cholestrol and Basal LH

Question 18

P4 In endcorine control

Answer 18

strong (-) feedback on hypothal
-reduces GnRH by tonic center
LH remains rel. high
follicles can still develop because FSH and LH remain, but follicles cannot reach preov status until P4 decreases and preov LH surge happens

Question 19

High P4 prevents

Answer 19

-Dvpmnt of preov follicles
-estradiol secretion
-behavioral estrus
-preov surge of GnRH and LH

Question 20

Luteolysis

Answer 20

Loss of P4 secretion by CL follow by loss of luteal tissue mass
last 1-3 days at end of luteal
Induced by PGF2a secreteed by the uterine endometrium (CL in primates)
Need communication between Uterine endo and CL
uterus also controls lifespan of CL

Question 21

complete uterectomy

Answer 21

CL lifespan prolonged and maintained as if pregnant
same with partial but less so

Question 22

CL lifespan (cutting ovary)

Answer 22

normal- 15-17 days
Complete uterectomy- 148 days (close to gestation time)
Partial Ipsilateral (same side as CL)- 35 days
Partial contralateral (opp side of CL)- no change
Intact ovary but transplant to neck gives a few weeks

Question 23

Overall uterus conclusion

Answer 23

mustbe close to CL (local effect)
secretes a substance causing lysis
PGF2a is the luteolysin

Question 24

Domestic Vs Primates PGF2a

Answer 24

domestic= uterin endo
humans= CL

Question 25

Physio impediemnts of getting PGF2a into the ovary

Answer 25

dilution and denaturation

Question 26

Vascular counter-current exchange mechanism

Answer 26

2 blood vessels flowing in opposite directions
low weight diffuse across blood vessel
utero ovarian relationship=transport

Question 27

Counter current diffusion

Answer 27

High to low [ ] (passive transport)
PGF2a enters uterine vein and lymph vessels
PGF2a transferred across the wall of uterine vein and into uterine artery

Question 28

Cl sensitivity to PGF2a

Answer 28

exogenous PGF2a caused luteolysis in 60 % of cycle
used as tool for estrus synch
countercurrent NOT present in mare so they experience less effect

Question 29

Luteolysis Hormones

Answer 29

CL
-P4 (large and small luteal cells)
-Oxytocin (large luteal cells)
Uterine Endometrium
-PGF2a production

Question 30

why is vascular countercurrfent thing important?

Answer 30

-prevents PGF2a dilution and denaturation
-ipsilateral utero-ovarian transport