MD2001 Flashcards
Oestradiol
Oestrogen
Where is the FSH and LH produced
Anterior Pituitary Glands
What are the 2 places in the hypothalamus that is responsible for ovarian control
Preoptic nucleus
Supraoptic nucleus
GnRH (6 features)
Produced in both males and females in the hypothalamus
Released as prohormone
Modified to active form
Secreted to hypophyseal portal system
Pulsatile
Delivered via hypophyseal portal circulation to anterior pituitary gonadotrobes via veins
Benefits of pulsatile hormones (3 features)
Low energy
Does not desensitise tissue receptors
Stress and other substances could influence the secretion of it
Function of ovaries (2)
Houses oocytes
Contains follicles in various stages of development
Stages of development of oocytes
Premordial Primary (has no theca cells; has granulose cells) Secondary Tertiary Graafin follicles
Theca cells (4)
Superficial layer
Has LH receptors
Changes cholesterol into pregnenolone
Produces androstenedione and testosterone
Granulosa cells
Deep layer
Layer increases in size during evelopment
Has LH and FSH receptors
Conert cholesterol into pregnenolone and activate aromatsa
Theca cells form testosterone and andestenodione
Donates them to granulose cells
FSH activate aromatase
Binds with androstenedione to form oestrogen
-
Types of oestrogen
Oestradiol
Oestrone
Oestriole
Functions of oestrogen on bones
Increases bone growth
Oestrogen on endocrine system
Increase progesterone
Oestrogen on liver
Increases clotting factor
Increases HDL
Increases steroid binding proteins
Decreases LDL
Oestrogen on reproductive organs
Increases uterine growth
Increases vaginal and Fallopian tube growth
Increases breast growth
Increases cervical mucus
Increases LH receptors on granulose cells
Secretion regulation of oestrogen
- Mid shift from negative to positive feedback, caused by changes of receptors (GnRH in anterior pituitary when oestrogen level is high)
2, Results in LH and FSH production before ovulation
Progestins
Progesterones
Produced in theca cells and granulose cells
Short half life (5 mins)
Regulation is linked to oestrogen
Develop materials to make milk but inhibit the production of milk
Menstrual cycle
Ovarian cycle + endometrial cycle
Ovarian cycle
Follicular phase
Luteal phase
Follicular phase
Due to the mature of Graafin follicles/secondary oocytes
Luteal phase
Dominated by corpus luteum
- Synthesise/secrete oestrogen and progesterone for implantation/maintenance of fertilised eggs
Corpus luteum regress and degenerates 10-12 days if no fertilisation
Endometrial cycle
Proliferative phase
Secretory phase
Menstruation
Proliferative phase
Endometrial growth due to increase of oestrogen
Blood vessel and gland growth occurs
Ovulation = end of phase
Secretory phase
Maturation but no growth of endometrium due to low level of oestrogen
Mucus glands fully develop
Glands and blood vessels increases surface area
Menstruation
If no conception, endometrial lining replaced
- Vasoconstriction of spiral arteries
- Local ischaemic injury
- Inflammatory cell infiltration
Lactation
Milk production and secretion
Mammary glands
Breast tissue prepared during puberty via female gonadal hormones
Development in pregnancy
Oestrogen Progestins - Prepares breast for milk production, but no milk is produced HcG from foetus Prolactin for milk production
Oxytocin
Let down milk
Follicular phase and luteal phase split by ovulation
-
Corpus luteum
What oocytes leave behind after ovulated
Stimulates production of hormones
Degenerates if fertilisation does not occur
Lydia cells
Produces testosterone
Testis
Contains:
Leydig cells
Blood vessels
Seminiferous tubules (produces sperm and house Sertoli cells)
Spermatogenesis
Spermatogonia Primary spermatocytes Secondary spermatocytes Spermatids Spermatozoa
Testosterone
Regulates spermatogenesis
Increase bone growth
Increases muscle and connective tissue
Increases size of testes, prostate, seminal vesicles and penis
Increase facial, axillary and pubic hair
Increases size of larynx
Increases sebaceous gland size and secretion
Testosterone secretion regulattyion
Pathway similar to ovaries except:
- Only 1 primary hormone (progesterone) vs. 2 primary hormone (oestrogen & progestins)
- No roles of acting established
Progestin
- Aids in conversion of endometrial cycling from proliferative to secretory phase
- Responsible for increase of body temperature in luteal phase of ovarian cycle
Negative feedback anterior pituitary in females
Oestrogen, progestins and inhibins
Positive feedback anterior pituitary in females
Activins
Negative feedback anterior pituitary in males
Testosterone and inhibins B
Negative feedback hypothalamus in males
Testosterone
Testosterone and dihydrotestosterone
Embryonic development of male genitals Accessory organs Growth of genitals; hairs Spermatogenesis Anabolic effects of musculoskeletal system
