Reproductive- Physiology Flashcards
Why is varicocele most common on left testis
Because the left spermatic vein enters the left renal vein at a 90° angle, flow is less laminar on left than on right left venous pressure > right venous pressure varicocele more common on the left.
Sertoli cells function
Secrete inhibin B inhibit FSH. Secrete androgen-binding protein Produce MIF. Tight junctions Support and nourish developing spermatozoa. Regulate spermatogenesis
Leydig cells function
Secrete testosterone in the presence of LH; testosterone production unaffected by temperature.
Estrogen
- source
Ovary (17β-estradiol), placenta (estriol), adipose tissue (estrone via aromatization).
Potency: estradiol > estrone > estriol
Estrogen
- Function
- Development of genitalia and breast
- Growth of follicle, endometrial proliferation
- feedback inhibition of FSH and LH, then LH surge
- stimulation of prolactin secretion.
- Increase transport proteins, SHBG; high HDL; low LDL.
Progesterone
- Source
Corpus luteum, placenta, adrenal cortex, testes
Progesterone
- Function
- Stimulation of endometrial glandular secretions and spiral artery development.
- Maintenance of pregnancy
- Decrease myometrial excitability
- Inhibition of gonadotropins (LH, FSH).
Oogenesis
1° oocytes begin meiosis I during fetal life and complete meiosis I just prior to ovulation (arrested in prophase).
Meiosis II is arrested in metaphase II until fertilization (2° oocytes)
If fertilization does not occur within 1 day, the 2° oocyte degenerates
Ovulation
High estrogen, high GnRH receptors on anterior pituitary. Estrogen surge then stimulates LH release ovulation (rupture of follicle).
increase temperature (progesterone induced).
Mittelschmerz
transient mid-cycle ovulatory pain (“Middle hurts”); classically associated with peritoneal irritation
Menstrual cycle
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Abnormal uterine bleeding
- Structural causes
- Non-structural causes
(PALM): Polyp, Adenomyosis, Leiomyoma, or Malignancy/ hyperplasia
(COEIN): Coagulopathy, Ovulatory, Endometrial, Iatrogenic, Not yet classified
Pregnancy
- Fertilization
- Implantation
- Syncytiotrophoblast
Fertilization occurs in upper end of fallopian tube (the ampulla). Occurs within 1 day of ovulation.
Implantation within the wall of the uterus occurs 6 days
Syncytiotrophoblasts secrete hCG, which is detectable in blood 1 week after conception and on home test in urine 2 weeks after conception
Calcutation of
- Gestational age
- Embryonic age
calculated from date of last menstrual period.
calculated from date of conception (gestational age minus 2 weeks)
Physiologic adaptations in pregnancy:
Increase HR
Anemia
Hypercoagulability
Hyperventilation
Human chorionic gonadotropin}
- Function
Maintains corpus luteum (and thus progesterone) for first 8–10 weeks. After, placenta synthesizes its own estriol and progesterone
hCG is High in
hCG is Low in
multiple gestations, hydatidiform moles, choriocarcinomas, and Down syndrome;
in ectopic/failing pregnancy, Edwards syndrome, and Patau syndrome.
Human placental lactogen (chorionic somatomammotropin.)
- Function
Stimulates insulin production, overall increase insulin resistence.
Maternal hypoglycemia from insulin resistance leads to lipolysis. Gestational diabetes can occur if maternal pancreatic function cannot overcome the insulin resistance.
Apgar
Appearance, Pulse, Grimace, Activity, and Respiration
Apgar scores < 7 require further evaluation.
10 poin scale
Infant/child development
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Low birth weight
Defined as < 2500 g. Caused by prematurity or intrauterine growth restriction (IUGR)
Menopause
Diagnosed by amenorrhea for 12 months. Usually preceded by 4–5 years of abnormal menstrual cycles.
Menopause before age 40 suggests 1° ovarian insufficiency (premature ovarian failure).
Androgens
Testosterone, dihydrotestosterone (DHT), androstenedione
Testosterone is converted to DHT by 5α-reductase, which is inhibited by finasteride.
In the male, androgens are converted to estrogen
by cytochrome P-450 aromatase
Testosterone
- Function
Differentiation of epididymis, vas deferens, seminal vesicles.
Growth spurt: penis, seminal vesicles, sperm, muscle, RBCs.
Deepening of voice.
Closing of epiphyseal plates.
Libido.
dihydrotestosterone (DHT)
- Functionn
Early—differentiation of penis, scrotum, prostate.
Late—prostate growth, balding, sebaceous gland activity.
Spermatogenesis
begins at puberty with spermatogonia. Full development takes 2 months. Occurs in seminiferous tubules.
Produces spermatids that undergo spermiogenesis (loss of cytoplasmic contents, gain of acrosomal cap) to form mature spermatozoon.
Tanner stages of sexual development
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