Flashcards in Session 2 - Hormone Stuff Deck (20)
What does LH act on in the male and what does it produce?
Leydig cells to promote the secretion of testosterone.
What are the actions of LH enhanced by in the male?
What are the actions of FSH in the male?
Acts on sertoli cells to facillitate spermatogenesis and produce inhibin
What are the three phases of the menstrual cycle?
What happens in the antral phase?
o LH binds to Theca Interna cells
o FSH binds to Granulosa cells
o As the follicle grows, more oestrogen is produced for a given amount of LH and FSH
What happens in the pre-ovulatory phase?
o Follicle has grown, and is producing a high amount of Oestrogen
o LH receptors develop in outer layers of Granulosa Cells
o [High] Oestrogen positively feeds back
o LH Surge produced
Follicle size increases, collagenase activity
FSH still being inhibited by Inhibin
What happens in the luteal phase?
o Remains of follicle reorganise into Corpus Luteum
o LH stimulates the Corpus Luteum
o Produces Oestrogen and Progesterone
Progesterone prevents +’ve feedback
Enhances –‘ve feedback
Prevents new follicles from developing ( FSH)
o As the Corpus Luteum grows, more steroids are produced for a given LH level
What are the two types of action of gonadal steroids?
Determinative and regulatory
List five determinative actions of testosterone
o Increase size and mass of muscles, vocal cords, bones
o Deepening of the voice
o Facial and body hair
o Increased stature
o Growth of the penis
List three regulatory actions of testosterone
o Maintenance of the male internal genitalia
Prostate, seminal vesicles, vas deferens, epididymis
o Metabolic (Anabolic) action
o Behavioural Effects
List seven actions of oestrogen
o Fallopian tube function
o Thickening of endometrium
o Growth and motility of myometrium
o Thin alkaline cervical mucus
o Vaginal changes
o Changes in skin, hair, metabolism
o Calcium metabolism
Give 7 actions of progesterone on oestrogen primed cells
o Further thickening of endometrium into secretory form
o Thickening of myometrium, but reduction of motility
o Thick, acid, cervical mucus
o Changes in mammary tissue
o Increased body temperature
o Metabolic (mild Catabolic) changes
o Electrolyte changes
What are the 5 anatomical parts of the female reproductive system which are changed during the menstrual system
What happens to the female reproductive tract during the follicular phase?
Steadily rising titres of oestrogen cause
o Fallopian Tube
Increase Secretion, motility, cilia
Increase Growth, motility
Thickness, glandular invaginations
Secrete a watery fluid, conductive to sperm
o Cervical Mucus
Thin, alkaline, conductive to sperm
o Vaginal Epithelium
What happens to the female reproductive system in the luteal phase?
Action of Progesterone on Oestrogen-Primed Cells
o Fallopian Tube
• Decrease Motility, secretion, cilia
Further thickening, decreased Motility
Further thickening, decreased secretion
Development of Spiral Arteries
o Cervical Mucus
Thickening, acidification. Inhibits sperm transport
o Mildly Catabolic
o Elevates basal body temperature
o Promotes change in Na+ and H2O excretion
With Oestrogen leads to net Na+ and H2O retention
What does the sudden fall in progesterone and oestrogen levels cause?
o The elaborate secretary epithelium of the endometrium collapses
o Apoptotic cell death
o Dead tissue shed as menstrual bleed.
o Spiral arteries contract to reduce bleeding.
How is testosterone release regulated by feedback control?
If Testosterone levels rise:
o GnRH secretion is inhibited.
Reduced LH and FSH
o LH and FSH are reduced further by testosterone reducing sensitivity of Gonadotrophs to GnRH
So Testosterone levels fall back
If Spermatogenesis proceeds too rapidly, Inhibin levels rise
o Inhibin reduces secretion of FSH by acting on Gonadotrophs
Describe the pattern of secretion of gonadotrophins and gonadal steroids at beginning of cycle
o Oestrogen, Progesterone, Inhibin levels low
o GnRH secretion is released from inhibition
o LH and FSH rise, FSH more as low Inhibin levels release FSH from selective inhibition at the pituitary
What causes follicles to grow?
FSH, followed by LH causes Follicles to Grow