1a Male and Female Reproductive Systems Flashcards
What does seminal fluid contain? FFFBC
Fructose, fibrinogen, fibrinolytic enzymes, bicarbonate, citric acid
Where are sperm produced?
In the epididymis
Why are the testicles suspended in the scrotum?
To keep them 2-3 degrees lower than the rest of the body
Why is essential that the testicles and therefore the epididymis remains at a suitable temperature?
A small increase in temperature can cause sperm production to stop
What transports sperm from the epididymis to the penis?
Van deferens
What is the spermatic cord?
The spermatic cord is the cord-like structure in males formed by the vas deferens (ductus deferens) and surrounding tissue that runs from the deep inguinal ring down to each testicle
What is the function of the seminal vesicle?
The seminal vesicles secrete fluid that will form part of the semen.
What type of nervous stimulation causes an erection?
Parasympathetic stimulation
What type of nervous stimulation causes ejaculation?
Sympathetic stimulation
How does a penis become engorged?
During erection, the corpora cavernosa will become engorged with arterial blood
What muscles make up the penis?
2 x Corpora Cavernosa
1 x Corpora Spongiosum
Where is the spermatic cord formed?
At the deep inguinal ring
What is involved with a vasectomy?
Cutting the vas deferens - this is how the sperm travel from the epididymis to the penis
What is the outer most layer of the testes called?
Tunica vaginalis
What does the tunica vasculosa contain?
Blood vessels
What is the tunica albuginea?
Tunica albuginea is the tough fibrous layer of connective tissue that surrounds the corpora cavernosa of the penis.
What is the arterial blood supply of the testes?
Testicular arteries from the aorta via the spermatic cord
What is the lymphatic drainage of the testes?
Para-aorticlymphnodes
What structures does the spermatic cord contain?
Testicular artery
Pampiniform plexus
Autonomic and GF nerves
Lymph vessels
Vas deferens
How many seminiferous tubules would you expect to find in the lobules of the testes?
1-4
In what cavity do the ovaries sit
The peritoneal cavity
What type of movement is engaged to move egg from ovaries into the central part of the reproductive tract?
Peristaltic movement
In what part of the fallopian tube does fertilisation occur in?
In the ampulla - the widest part of the fallopian tube
What supports the uterus?
The tone of pelvic floor and ligaments
What muscles are found on the pelvic floor?
Levator ani and the coccygeus
During menses, what is shed?
The endometrium
What is the endometrium?
The lining of the uterus
What is found 1 cm lateral to the uterus? and why is this clinical relevant?
Ureter - cervical cancer spread to the ureter
How are all areas superior to the cervix stable?
The presence of lactobacillus bacteria - they secrete lactic acid and lower the pH meaning it kills and inhibits the growth of other bacteria
What can occur when the vagina flora is disrupted?
Infection, as there is nothing to kill possible bacteria which may enter into the vagina
What supplies the female reproductive system with arterial blood?
Ovaries supplied from the ovarian arteries
Uterus / Vagina from the uterine arteries
What is the lymphatic drainage of the ovaries?
Para-aortic lymph nodes
What is the lymphatic drainage of the uterus/vagina?
Iliac, sacral, aortic and inguinal lymph nodes
Where does spermatogenesis occur?
In the infratubular compartment of the seminiferous tubules
How long does it take for sperm to be ready for release?
64 days
What is the genotype of a primary spermatocyte?
44XY
What is the genotype of a secondary spermatocyte which has undergone meiosis 1?
22X or 22Y
What is the name given to the product of meiosis 2 in spermatogenesis?
Spermatid
What is the genotype of a sperm?
22X or 22Y
What are the three layers of the uterus called?
Endometrium, myometrium and perimetrium
What happens after the oocyte and sperm fuse?
The fusion of the secondary oocyte and sperm causes a calcium influx, produces OVA
What happens to the oogonia in the 2nd trimester?
All the oognia in the foetus develop into primary oocytes forming primordial follicles
What is a polar body?
A halpoid cell with basically no cytoplasm - formed as it separates from the oocyte during meiosis
What is the outermost layer of the seminiferous tubules called?
Tunica propria
What are spermatogonium?
a cell produced at an early stage in the formation of spermatozoa, formed in the wall of a seminiferous tubule and giving rise by mitosis to spermatocytes
What receptors do Sertoli cells contain?
FSH receptors
What is the function of the Sertoli cells?
To support the developing germ cells and assist the movement of germ cells to tubular lumen
From where to where do Sertoli cells transfer nutrients?
From capillaries to developing germ cells
Where is FSH secreted from?
The anterior pituitary
Where is Anti-Mullerian hormone produced?
The gonads
What does Anti-Mullerian Hormone do?
It aids the regression of the malarian ducts in male sex development - otherwise the male would form fallopian tube
What does Androgen-Binding Protein do?
Helps direct testosterone from the Leydig cells to the germ cells
Where are Leydig cells found?
Between the seminiferous tubules
Why do leydig cells have a pale cytoplasm?
They contain alot of cholesterol
What receptors do Leydig cells have?
LH receptors
What indicates that Leydig cells make hormones/
They contain alot of cholesterol and hormones are derived from cholesterol
Apon LH stimulation, what is released from the Leydig cells?
Testosterone, Androstenedione and Dehydroepiandrosterone (DHEA)
How many sperm are produced per second?
1500 per second
When does gametogenesis start?
At the start of puberty
What is produced from spermatogenesis?
Mature spermatozoa
What process occurs in the male testes?
Spermatogenesis
What process occurs in the female ovaries?
Oogenesis
What is the difference in fertility between men and women?
Women have finite fertility (up until menopause) whereas men have infinite fertility
What are the three oestrogens?
Oestradiol, Oestrone and Oestriol
What are the three androgens?
Testosterone, Androstenedione and DHEA
What does relaxin do?
Relaxin is a hormone produced by the ovary and the placenta with important effects in the female reproductive system and during pregnancy. In preparation for childbirth, it relaxes the ligaments in the pelvis and softens and widens the cervix.
What does the hormone inhibin do?
It inhibits the synthesis and release of the follicle-stimulating hormone in the pituitary gland and reduces the hypothalamic LH - releasing hormone content.
Where is inhibin produced in men and women?
Men = sertoli cells
Women = granulosa cells
Where is seminal fluid mainly produced?
Accessory sex glands
What are the accessory glands?
Seminal vesicles
Prostate
Bulbourethral glands
why do the spermatogonia undergo differentiation and self renewal?
Ensures that there is a continual pool available for subsequent spermatogenic cycles through lifetime - continual fertility
What secretes progesterone and oestrogen during folliculogenesis?
Corpus luteum
During pregnancy, what produces progesterone and oestrogen?
Placenta
What cell is associated with the outer part of the ovarian follicle?
Theca
What is the function of the theca cell?
Structural and functional support of the growing follicle in folliculogenesis
What do the theca cells produce?
Androgens due to LH
What does overactivity of theca cells lead to?
High androgen levels - leads to infertility
what cell is associated with the inner part of the ovarian follicles?
Granulosa cells
What is the function of the granulosa cell?
When stimulated by FSH, they convert androgens into oestrogens
What enzyme is used to convert androgens into oestrogens?
Aromatase
What happens to granulosa cells after ovulation?
Granulosa lutein cells
What do granulosa lutein cells produce
Progesterone and relaxin
How does progesterone promote pregnancy?
maintaining endometrium
What are the primary reproductive hormones?
LH and FSH
Where are kisspeptin released from?
Kisspeptin neurones in the hypothalamus
What does kisspeptin act directly on?
The GnRH neurones to stimulate the release of GnRH = gonadatrophin releasing hormone
How does GnRH travel down the anterior pituitary?
Via the hypophyseal portal system
What receptors does GnRH bind to after travelling down the hypophyseal portal system?
Binds to receptors on the gonadotrophs
What do the gonadotrophs produce?
LH and FSH
What type of secretion rhythm do the sex steroid hormones show?
Diurnal rhythm
Why are morning erections common?
Due to the diurnal fluctuations in sex steroid hormone concentrations, they are higher in the morning, resulting in increased testosterone
Why can GnRH not be measured in a blood test?
The levels are too low as GnRH is contained primarily within this local circulation
In males, what does the FSH that is released from the gonadotrophs do?
Acts on the Sertoli cells to produce inhibin
In males, what does the LH that is released from th gonadotrophs do?
Acts on the Leydig cells to produce testosterone
Where does testosterone act upon in negative feedback loops when it is secreted?
Acts to inhibit the hypothalamus and the anterior pituitary
Where does inhibin act upon in negative feedback loops?
The anterior pituitary gland
What stimulates the Theca cells in females to produce androgens?
LH
What effect does the FSH secreted from the anterior pituitary have on the Granulosa cell?
Causes it to convert androgens into oestrogen, and produce inhibin
What is hyperprolactinaemia?
When there is an over production of prolactin
What does hyperprolactinaemia result in?
The inhibition of kisspeptide neurones
How does hyperprolactinaemia inhibit kisspeptin release?
The prolactin binds to prolactin receptors on kisspeptin neurones in the hypothalamus which inhibits kisspeptin release
What other conditions can hyperprolactinaemia result in?
Oligo-amenorrhoea
Low Libido
Infertility
Osteoporosis
What can cause an excess of prolactin?
A prolactin secreting tumour, drugs, disturbances to the pituitary gland
Which hormone is negative feedback on the hypothalamus pituitary-gonadal axis primarily mediated by?
Oestrogen
What enzyme is used to convert testosterone to oestrogen?
Aromatase
What hormone will be found in excess when a patient has aromatase deficiency?
testosterone
Why are patients with an aromatase deficiency often tall?
They lack oestrogen as they cannot convert testosterone into oestrogen, and oestrogen is needed in order for the epiphyseal growth plates to fuse in long bone which halts growth
What can an aromatase deficiency present as?
lower voice, facial hair, acne
How can an aromatase deficiency lead to osteoporosis?
Oestrogen is needed to maintain bone density, meaning low bone density = osteoporosis
Nutrients (eg fructose) & glycoprotein secretion into epididymal fluid is induced by what?
Androgens
Tubular fluid reabsorption resulting in concentration of seminal fluid is induced by what?
(induced by oestrogen)
How many km does the spermatozoa travel from testis to fallopian tube?
150km
What is the ampulla?
The widest part of the fallopian tube where fertilisation occurs
Why is there a requirement for such a large number of spermatozoa?
Only 1 in a million actually reach the ovum
What is fibrinogenase?
A fibrinolytic enzyme which is found in seminal fluid
What are the three stages of the capacitation of the sperm?
Loss of glycoprotein ‘coat’
Change in surface membrane characteristics
Develop whiplash movements of tail
Where does the capacitation of the sperm take place?
In ionic and proteolytic environment of the fallopian tube
What two substances is the capacitation of the sperm dependant on?
Oestrogen and calcium
What receptor does the capacitated sperm bind to during the acrosome reaction?
ZP3
What stimulates the Ca2+ influx into the sperm during the acrosome reaction?
Progesterone
What is released from the acrosome?
Hyaluronidase and proteolytic enzymes
During the acrosome reaction, which layer of the ovum is penetrated?
The zona pellucida
How is poly spermy prevented?
The cortical granules which are released degrade the zona pellucida, meaning there are now no more receptors for the sperm to bind into
What does hyaluronidase do?
Breaks down polysaccharides
Where does the process of fertilisation occur?
Within the widest part of the fallopian tube - ampulla
What happens to the genetic content of the ovum during fertilisation?
changes from haploid to diploid as a zygote is formed
What happens to the second polar body during fertilisation?
It is expelled from the ovum
how long does the free-living phase of the conceptus last?
9-10 days
During the free-living phase, how does the conceptus receive nutrients?
From uterine secretions
8 cell conceptus compacts to form what?
Morula
What occurs during the attachment phase of implantation?
The outer trophoblast cells contact theuterine surface epithelium
What stage of implantation follows from the attachment phase?
The decidualisation phase
What happens in the decidualisation phase?
Changes to the underlying uterine stromal tissue
What hormones does implantation require?
Progesterone domination in the presence of oestrogen
How does progesterone affect the implantation phase?
Promotes gestation - It prepares the endometrium for implantation
What does Leukaemia inhibitory factor (LIF) do?
Stimulates the adhesion of blastocyst to the endometrial cells
What are the three factors which are involved in the attachment of the blastocyst?
Leukaemia inhibitory factor, interleukin-11 and progesterone
What are the endometrial changes which occur due to progesterone?
Glandular epithelial secretion
Glycogen accumulation in the stromal cell cytoplasm
Growth of capillaries
Increased vascular permeability (→oedema)
What are the factor involved in decidualisation?
Interleukin-11 (IL11), histamine, certain prostaglandins & TGFb (TGFb promotes angiogenesis)
What hormone is responsible for managing uterine contractions during parturition?
Oxytocin
What affect does oxytocin have on the cervix?
Dilates the cervix
During late pregnancy, what happens to the number of oxytocin receptors?
It increases
Why is hCG only present during pregnancy?
It is produced by the placenta
What is human placental lactogen?
made by placenta and modulates maternal metabolism to provide nutrients for fetus eg causes insulin resistance therefore more glucose circulating for fetus.
During the early stage of pregnancy, what hormone is very high?
hCG
As pregnancy progresses which hormones increase in concentration?
Oestrogen and progestone
From what day does the placenta start making oestrogen and progesterone?
Day 40
How does hCG ensure that oestrogen is being produced even when Oestrogen suppresses LH?
The hCG acts like LH and acts on LH receptors to stimulate oestrogen production
what does hCG share with TSH?
A common alpha-subunit
What is the main substrate for oestrogens and what can make it?
DHEAS - made by mother and foetus
How does the placenta make progesterone?
From cholesteronl
Why is there an increase in iodothyronines during pregnancy?
as increased requirement – driven by hCG which shares common alpha subunit w TSH – leads to lower TSH in T1/2
What affect may pregnancy have on patients with hypothyroidism?
Increase thyroxine by 20-30% as they do not have adequate thyroid hormones to respond to the increase in hCG
what happens to ACTH levels during pregnancy?
They increase as more cortisol is needed for fetal lung development
What happens to adrenal steroid levels during pregnancy?
They increase
What produces progesterone and oestrogen in the first 40 days of pregnancy?
The corpus leuteum
What stimulates the corpus luteum to produce oestrogen and progesterone?
hCG
During the first 40 days of pregnancy, why does hCG act on the LH receptors instead of oestrogen?
hCG binds to the LH receptors which increases the production of eoestrogen and progesterone - increasing oestrogen inhibits LH, meaning it cannot act on its own receptors, so hCG acts instead
Why can you not monitor a prolactinoma via prolactin levels during pregnancy?
The levels are increased anyways
How are prolactinomas monitored during pregnancy?
They are monitored using visual fields like MRIs to check the tumour is not imposing on the optic chiasm
Why does TSH levels decrease during pregnancy?
- hCG is high during pregnancy
- hCG and TSH share a common alpha subunit
- Therefore hCG also stimulates the pituitary
- A stimulated pituitary then increases negative feedback on TSH, therefore reducing TSH levels
What is the increase in Parathyroid hormone related peptides produced by”
The breast tissue
What affect does an increase in PTH-related peptides have on the foetus?
Increases calcium 2+ ions for the fetal skeleton
Why does pituitary Growth Hormone decrease?
The placenta makes GH, so less is needed from the pituitary as there is a negative feedback loop
What three things are oxytocin responsible for?
- Uterine contractions
- Cervical dilation
- Milk ejection
What is the key endocrine hormone involved in parturition?
Oxytocin
Which hormone is responsible for milk production?
Prolactin
Describe the endocrine control of lactation?
Suckling on the nipple acts as a sensory stimuli
This activates neural pathways to the hypothalamus which acts on the anterior pituitary to produce prolactin and the posterior pituitary to produce oxytocin which are involved in milk synthesis and milk ejection respectively
What does the epithelium of the vagina secrete? And why is this useful?
Secretes glycogen - this is used by the lactobacillus bacteria as energy source - allows the production of lactic acid which lower the vaginal pH and therefore limits the growth of harmful pathogens
How is everything above the cervix sterile?
- endometrial shedding
- Presence of thick cervical mucus
- Narrow opening
- Low pH of the vagina
How does the combined contraceptive pill work?
Contains both O and P - therefore FSH and LH are both inhibited, and therefore no follicles will rupture and ovulation does not occur
