Gonads

Question 1

What do the gonads develop into?

Answer 1

Gonads develop as testes in males and ovaries in female

Question 2

What are the 2 functions of gonads?

Answer 2

Testes-spermatogenesis, and horomonal andorgen producion

Ovaries-Oogenesis and production of ostrogens and progesterone

Question 3

How does the number of spermatogonia cells vary with age?

Answer 3

Spermatogonia cells rapidly increase in the wound-reaching 6*10^6 cells-and stays there the whole life (slightly lower with age)

Question 4

How does the number of oogonia cells vary with age?

Answer 4

Start at develoment with around 510^6-but before birth drops to 210^6. By puberty, around 500 000 cells remain-and 0 by menopause
quickly lost

Question 5

Describe the general steps of spermatogenesis. When does in happen it male? How fast?

Answer 5

Start from a germ cell-self replicate and differenciate to spermatogonia. These then become primary spermatocytes by undergoing first meitic division, and secondary spermatocytes after second meitic division (haploid)
The haploid cells are matured to spermatides, then spermatozoa (sperm)
gametogenesis begins at puberty-spermatogonia are main cell type renewing and differenciating-levels stay constant
Male can make 500 sperm/gm testis/second

Question 6

Describe the general steps of oogenesis. When does in happen it females? How fast?

Answer 6

Germcells make oogonie by mitotic division-then first meiosis makes primary oocytes, and second meiosis makes secondary oocytes-these then make the ovum
oogonia start around 6mil, but entry in meisosi is halted in prophase-by birth, the oogonia remaining for POTENTIAL new eggs are less than 500 000
Primary oocytes are release from prophase 1 each month, until menopause when none left

Question 7

Describe the anatomy of the testes and how it relates to production of homones and sperm

Answer 7

Testes-made of coiled seminiferous tubules (make testes) connected to rete testis (collection point)-connected to vasa efferentia, epididymis (tube), which becomes vas deferens (sourrounded by SMC for ejaculation)-to urethra
Cross section of seminiferous tubule reveals an exterior of spermatogonia, then large layer of sertoli cells and inside a lumen for spermatozoa
Spermatogonia divide in the exterior, and pass through sertoli cell specialised junction to pass to lumen as finished sperm
near all these cells leydig cells sit

Question 8

Explain the role of sertoli and leydig cells

Answer 8

Sertoli cells-form the semriniferous tubules-synthesis FSH and adrogen RECEPTORS
In respond to FSH produce various molecules including INHIBIN-major role in developing spermatocytes
Leydig cells sit outside seminiferous tubules-mainly LH receptors. Produce adrogens in response to LH (mainly testosterone

Question 9

Describe the anatomy of the ovaries and how it relates to production of homones and oocytes

Answer 9

large area where many follicules are undergoin atresia (stopping)-one will be selected per month as the graffian follicule-becomes an independen homone machine
Exterior of graafian follicul are thecal cells, followed by several layers of granulosa cells-then some follicular fluid, and at the center the ovum

Question 10

Describe the processes of making gonadal homones

Answer 10

They all orginiate from cholesterol (and progesterone)-made in adrenals and gonads
From there, prognolone can make progesterone (in adrenals makes aldosterone
Next one, 17 OH progesterone can make cortisol
in the gonads, 17OH progesterone can be made to testosterone, oestrone (and teso can then makes 17b ostradial (or oestrogen)

Question 11

Describe the possible fates of testosterone, its transport in blood and roles in the male body

Answer 11

In some organs-reduced to digydroestosterone (DHT)-superpotent testosterone
In adrenals, testes (sertoli)-aromatised to oestogens
transport-in blood, mainly bound to sexhomone binding globulin (60%), some to albumin (30%) and about 2% free (active)
In semniferous fluid-androgen binding globulin
Roles
A) Foetus: Develomment of male internal and etxernal genetalia, and foetal growth
B)Adult-needed for spermatogenesis
Helps develoment of male genetalia and secondary sec characteristics (facial hair), protein and bone anabolism (muscle growth)
Behavioral-male sexual behaviour, puberty growth spurt with GH
Has andogenic effects trough conversion to oestrogen

Question 12

What are oestrogens, describe there role and repeat for progestogens

Answer 12

Oestrogens are any substance (natural or not) which induces mitosis in endometrium-mainly 17b oestradiol, oestriol, oestrone (precusor)
Main effects are-stimulating endometrium proliferation (womb thicken); and help menstrual cycle with LH surger for ovulation
feedback on GnRH, stomulate osteoblast, acts on lipids and behavioral effects
smaller effects on vagina secretion, breast growth, skin reduce sebaceous gland), increase salt reabsotption, plasma prot synthesis and other hromones (prolactin)

Progestogens-any substance inducing secretory change in endometrium (progesterone, 17a-hydroxyprogesterone)
MAin role is secretion of endometrium and cervix
Smaller-negative feedback on GnRH, increase BBT, inhibitory of aldosterole, growth of alveolar in breast

Question 13

Describe all the parts of the hypothalamo-pituary-testicular axis

Answer 13

Hypthalamus produces waves (up and down) or GnRH, causing anterior pit to release waves of LH and FSH
FSH to setoli cells-spermatogenesis (needs testosterone) and production of inhibin-negative feedback on pit and hypothalamus
LH to leydig cells-produce tesosterone-negative feedback to pit and hypothalamus + normal effects

Question 14

Describe the small parts of the hypothalamo-pit-ovarian axis without going into the menstrual cycle

Answer 14

Simply hypothalamus produce GnRH, pit release FH and FSH to ovary-regulation is all part of mentsual cycle-other cards

Question 15

Recall the levels of homones (LH, FSH, Ostradial and progesterone) and what is happening in early follicular phase

Answer 15

Start of the cycle (day 1 when bleed)-LH and FSH are slightly high but constant
Ostradiol and progesterone nearly at 0
LH and FSH (and GnRH) act on ovary causing develoment of many follicules-small amounts of ostradiol (and progestrone (tiny amounts)) negative feedback on LH and FSH

Question 16

Recall the levels of homones (LH, FSH, Ostradial and progesterone) and what is happening in early-mid follicular phase. Mention the local feedback loop between follicules and oestogen

Answer 16

FH and FSH similar to early follicular phase, but 17b oestradiol levels start to rise and produced by follicules
LH and FSH still acting- one follicule is selected in ovary and grows much bigger than others-increase production of ostradiol
follicule produces E2 oestrogen which uprrgulaes granulosa cell growth-which in turn produce more E2
as follicule grows, levels of E2 raise faster

Question 17

Recall the levels of homones (LH, FSH, Ostradial and progesterone) and what is happening in mid follicular phase

Answer 17

Graafian follicule develops-no longers require FSH to develop-keeps growing and producing large E2 armounts
Large amounts E2 and inhbins leads to downregulating of LH (and very slight dip in FSH)

Question 18

Recall the levels of homones (LH, FSH, Ostradial and progesterone) and what is happening in late follicular phase

Answer 18

Peak E2 is reached a bit before egg release (and LH peak)-when that high, graafian E2 causes positive feedback to LH-causes a LH surge (and immediate drop) (and small FSh)-causes release of egg-ovulation around day 14
small peak of progestrone too

Question 19

Recall the levels of homones (LH, FSH, Ostradial and progesterone) and what is happening in luteal phase

Answer 19

if no fertilisation-graafian follicule w/o egg becomes corpus luteum-and starts producing very high levels of progesterone (LH and FSH lower-direct inhibition of pit). Continues making ostrodiol, and start inhbin
Luteolysis and menstruation follow as progestrone peaks around day 22 (ostradiol also high around that time (refulatory)

Question 20

What does Amenorrhoea means? and oligomenorrhoae?

Answer 20

Defined by absence of menstrual cycles entirely
Primary if never had one, secondary if had then stopped
Oligomenorrhoea is infrequent cycles

Question 21

Define infertility, and list the main causes for it

Answer 21

Defined as couple cant get pregant after 12 month of unprotected sex
Causes- pit failure, prolactinoma (cancer causin prolactin), testicular failure (mumps, Kleinfelter)
ovarian failure (tuners syndrome)
polycyctsic ovarian syndrome (infrequent periods, hyperandogenaneamia (icrease male pattern hair, acne), polycystuc ovaries (increase number of enlarging ovarian follicules)