1a Male and Female Reproductive Systems Flashcards
What does seminal fluid contain? FFFBC
Fructose, citric acid, bicarbonate, fibrinogen and fibrinolytic enzymea
Where is seminal fluid produced?
In the epididymis (small contribution)
Main: accessory sex glands :
- Seminal vesicles
- Prostate
-Bulbourethral glands
Why are the testicles suspended in the scrotum?
To keep them 2-3 degrees lower than the rest of the body so that sperm production can continue
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?
Vas deferens
What structures does the spermatic cord contain and where is it formed
- Testicular artery
- Pampniform plexus of veins
- Autonomic nerves
- Lymph vessels
- Vas deferens
What is the function of the seminal vesicle?
Secrete seminal fluid
What is the function of the epididymis?
- Stores and transports sperm
- Produces seminal fluid
- Matures sperm
- Destroys sperm that is not ejaculated
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-aortic lymph nodes
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 and stops it form prolapsing out of vagina ?
- The tone of pelvic floor - levator ani and coccygeus muscles
- Uterosacral 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 kept sterile?
- Low pH due to production of lactic acid by lactobacillus bacteria
- Shedding of endometrium
- Thick cervical mucus
- Narrow external os
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 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
Hormone synthesis
How do Sertoli cells support developing germ cells
- Transport nutrients from capillaries to developing germ cells
- Assist in movement of germ cells to tubular lumen
- Phagocytosis of damaged germ cells
Where is FSH secreted from?
The anterior pituitary
Which 3 hormones are synthesised by Sertoli cells
- Inhibin and activin
- Anti- Mullerian hormone
- Androgen binding protein
What does Anti-Mullerian Hormone do?
It aids the regression of the Mullerian 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 is the main function of Leydig cells
Hormone synthesis
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
Describe the process of oogenesis
- In second trimester of pregnancy, all Diploid Oogonia in foetus develop into Diploid Primary Oocytes (forming primordial follicles) by mitosis
- By Menarche, the Primary Oocytes divide into Haploid Secondary Oocytes via meiosis
- Secondary Oocytes divide into Haploid Ootids via meiosis
- Ootids differentiate into Ova.
What is a polar body?
A haploid cell with basically no cytoplasm that is produced because oocytes do not divide evenly
Describe the process of folliculogenesis?
1) Primordial follicle (primary oocyte at birth)
2) Primary (aka preantral) follicle → primary oocyte and layers of granulosa and outer theca cells
3) Secondary (aka antral) follicle → fluid-filled cavity (antrum) develops FSH an LH receptors
4) Mature (aka Graafian/preovulatory) follicle → forms due to LH surge - secondary oocyte formed
5) Ruptured follicle, ruptures surface of ovary
6) Corpus Luteum → produces progesterone and oestrogen (stimulated by LH/hCG) and in pregnancy, production of these is taken over by placenta
What secretes progesterone and oestrogen during folliculogenesis?
Corpus luteum
During pregnancy, what produces progesterone and oestrogen?
Placenta
How does the dominant follicle form?
The follicle that produces the most oestrogen is chosen as dominant causing FSH stimulation of other follicles to stop.
What are the three oestrogens?
Oestradiol, Oestrone and Oestriol
What are the three androgens?
Testosterone, Androstenedione and DHEA
What reproductive hormones are produced by the ovaries?
Oestrogens
- Oestradiol
- Oestrone
- Oestriol
Progestogens
- Progesterone
Androgens
- Testosterone
- Androstenedione
- DHEA
Relaxin
Inhibin
What does relaxin do?
relaxes the ligaments in the pelvis and softens and widens the cervix in preparation for pregnancy
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
What cell is associated with the outer part of the ovarian follicle?
Theca
What is the function of the theca cell?
Support of folliculogenesis
Hormone synthesis
What do the theca cells produce?
Androgens due to binding of LH to LH receptors on theca cell
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?
Hormone synthesis
What does FSH do to the granulosa cell?
- Binds to FSH receptors to convert androgens to oestrogens
What enzyme is used to convert androgens into oestrogens?
Aromatase
What hormones are produced by the granulosa cells
Inhibin and activin
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
Describe the HPG axis
1)Kisspeptin neurones release kisspeptin
2) GnRH travels down Hypophyseal-Portal Circulation to the Anterior Pituitary
3) LH/FSH released from Gonadotrophs of anterior pituitary to gonads
4) This causes oestrogen/progesterone/androgen to be produced
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
Where does testosterone act upon in negative feedback loops when it is secreted?
Acts to inhibit the hypothalamus and the anterior pituitary
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 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)
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?
the fallopian tube
What two substances is the capacitation of the sperm dependant on?
Oestrogen and calcium
Describe the acrosome reaction
Process in which sperm reaches ovum
1. Sperm binds to ZP3 (sperm receptor).
2. Ca2+ influx into sperm stimulated by progesterone
3. Release of hyaluronidase and proteolytic enzymes from acrosome
4. Sperm penetrates the zona pellucida (glycoprotein layer surrounding plasma membrane of oocyte)
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
Describe the cortical reaction
- Cortical granules release molecules which degrade the Zona Pellucida
- Therefore any further binding of sperm to ZP2 and ZP3 is prevented as there are no receptors
- Haploid gametes form diploid zygote
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 are the stages for the development of conceptus after the fertilisation?
- Cell continues to divide as it moves down Fallopian tube to uterus (3-4 days)
- Receives nutrients from uterine secretions
- This free-living phase lasts 9-10 days
- Inner cell mass will form the embryo
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 are the three factors which are involved in the attachment of the blastocyst?
Leukaemia inhibitory factor, interleukin-11 and progesterone
What does Leukaemia inhibitory factor (LIF) do?
Stimulates the adhesion of blastocyst to the endometrial cells
What stage of implantation follows from the attachment phase?
The decidualisation phase
What happens in the decidualisation phase?
Endometrial changes due to 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 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
In the first 40 days how is progesterone and oestrogen produced during pregnancy?
hCG produced by trophoblasts acts on receptors of corpus luteum to stimulate oestrogen and progesterone production in corpus luteum.
During the early stage of pregnancy, what hormone is essential for the maintenance of the corpus luteum?
hCG
During late pregnancy, what happens to the number of oxytocin receptors?
It increases
What does hCG do to LH and FSH during pregnancy?
Inhibits both
What three things are oxytocin responsible for?
- Uterine contractions
- Cervical dilation
- Milk ejection
Why is hCG only present during pregnancy?
It is produced by the placenta
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 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 stimulates the corpus luteum to produce oestrogen and progesterone?
hCG
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 effect does an increase in PTH related peptides have on the foetus
Increases Ca2+ ions for the fetal skeleton
Why does pituitary growth hormone decrease?
The placenta makes growth hormone
