Reproduction Flashcards
Which structures form the ‘walls’ of the pelvic cavity?
Superior - no real wall, continuous with abdominal cavity.
Inferior - pelvic diaphragm
Lateral - hips bones and obturator
Anterior - pubic bones + pubic symphysis
Posterior - sacrum + coccyx + piriformis muscle
What are the 3 pairs of Pelvic apertures and what structures pass through them?
- Obturator foramen - for obturator nerve
- Lesser sciatic foramen - for perineal structures
- Greater sciatic foramen - literally everything else
Which structures pass above the piriformis and which structures pass below?
Superior gluteal nerves and vessels pass through the greater sciatic foramen above the piriformis.
Everything else, including the inferior gluteal and sciatic nerves, passes below piriformis.
What are the muscles of the pelvic wall?
Obturator internus and the piriformis (virtually horizontal). Both joint to greater trochanter of the femur. Obturator internus basically covers obturator foramen.
Functions of the pelvic floor?
- Supports pelvic organs
- lift the floor to release feaces
- resist changes to abdo pressurisation - i.e so you don’t piss yourself when you cough
What is the main muscle group of the pelvic floor, what muscles makeup this group and weakness in these muscles leads to what?
Levator Ani, made up by muscles with either pubo- or coccygeus in them. Weakness in this area can lead to incontinence.
Which muscle of the levator ani is most important for me to know and what does it split into?
Pubococcygeus muscle - becomes the muscle that holds onto all the structures that pierce the pelvic floor and others. Puboanalis, pubovaginalis, puboprostatatis. Puborectalis is most important runoff as it controls fecal continence - like a sling.
What are the two holes of the pelvic floor?
Urogenital hiatus and anal aperture.
Where does the peritoneum end? What pelvic structures are covered in peritoneum?
The peritoneum does not cover the pelvic floor, it rests on the superior part of it. The only organ totally covered in peritoneum are the uterine tubes.
The draped nature of the peritoneum over the pelvic floor forms what structures in females and males?
2 pouches in females: vescio-uterine pouch and recto-uterine pouch.
In males: recto-vesical pouch.
The peritoneum is loose over which structure?
Bladder, to allow for expansion.
Name the pelvic floor ligament I must know:
hypogastric sheath - all important structures must pass through.
What unrelated structure could a hysterectomy damage?
The uterine vessels lie next to the ureters, so could damage them.
Describe the blood supply of the pelvis.
The abdominal aorta turns into the common iliac artery which turns into the internal iliac which does pelvis and the external iliac which becomes the femoral artery.
The internal iliac then splits into posterior and anterior trunks.
Posterior - iliolumbar, lateral sacral, superior gluteal
Anterior - umbilical, internal pudendal (perineum) and middle rectal.
Where do most perineal structures attach?
To the perineal body (gooch).
List the layers of the anterior perineal triangle in order.
Skin, superficial fascia, deep fascia, superficial perineal pouch, perineal membrane, deep perineal pouch, muscles.
Describe the erectile bodies in males and females.
Both of Corpus cavernosa.
Females then have clitoris and males have corpus spongiosim (continues as head of penis).
Where are the external urethral sphincters?
These voluntary sphincters for voiding are present in the deep perineal pouch.
Males also have an involuntary internal urethral sphincter.
What nerves supply the perineum?
The nerve is the pudendal nerve (S2-S4) which splits into all the rectal, perineal, penis nerves etc. Pudendal nerve exits greater sciatic foramen and renters pelvis through the pudendal canal - really interesting course.
What arteries/veins supply the perineum?
Pudendal artery off the internal iliac, just follows the pudendal nerve.
Most empty into internal iliac vein.
Exception is penis dorsum which is the deep dorsal vein for.
Where do testes empty their lymph?
Unlike other perineal structures which tend to do inguinal nodes, the testes empty into the para-aortic and lumbar nodes, so any pain (often not present) will present with abdo pain.
What are the broad steps of oocyte/zygote growth.
- Ovulation
- Fertilisation
- Cleavage
- Morula - ball
- Blastocyst - hollow ball
- Implantation - after a week
- Gastrulation - germ layers
What are the two divisions of the blastocyst before implantation?
Trophoblast (will become placenta) and inner cell mass (will become embyro)
Explain Gastrulation
Starts with primitive streak.
Invaginates one end of the epiblast. Cells migrate through the invaginated groove between the epiblast and hypoblast (yolk) to form endoderm and then mesoderm. Remaining epiblast cells become ectoderm.
All cells will come from these layers except germ cells.
What is situs invertus?
Incorrect positioning of organs due to issue with left-right cilia of primitive node.
Which germ layer gives rise to the notochord?
Mesoderm.
What happens if the primitive streak does not disappear as the notochord forms?
Teratoma
Explain the formation and development of the neural tube and neural crest.
The neural tube is ectoderm that starts as neural plate and will become spine.
Neural crest are cells left out of the neural tube as it joins and they migrate to the sides and become the ganglia, melanocytes and schwann cells.
What structures does the ectoderm become?
CNS, melanocytes, epidermis
What structures does the mesoderm become?
Paraxial - somites (dermis, muscles, bones)
Intermediate - urogenital system
Lateral - heart, gut wall, vessels, some bones
What are the 3 embryonic stages of the kidneys?
- Pronephros - disintegrates quickly
- Mesonephros - embryonic kidney
- Metanephros - becomes adult kidney
Explain the Wolffian and Mullerian tubules and which hormones are involved.
Embryonic kidney system starts off as Wolffian tube.
Wolfian tube needs testosterone to survive and needs AMH (anti-mullerian hormone) to kill Mullerian system (XY).
Mullerian duct grows in absence of testosterone and AMH (XX).
What structures does the endoderm become?
Digestive tube and respiratory structures.
Why do pregnant women take folate?
To help the neural tube grow properly
What can parvovirus cause congenitally?
Anemia, heart issues
Why does rhesus blood group matter in pregnancy?
If Mum is negative and baby is positive (from dad) can get autoantibodies. Would only be after first baby.
What are the screening options for pregnancy?
Combined screening (blood test for Hcg and Papp-A) and ultrasound for nuchal translucency)
OR
Non-invasive pre-natal testing (NIPT).
- checks fetus DNA in mums bloodstream
What are the diagnostic congenital genetic abnormality tests?
Amniocentesis and chorionic villous testing (CVT).
Which vital factors go up and down in pregnancy?
Due to increased fluid movement needs, CO (HR and SV) goes up. BV goes up for baby. As a result of all of the above, TPR goes down to try to mitigate pressure.
What molecules does the posterior pituitary release?
Oxytocin and ADH
Describe the meiotic stages in a female in terms of chromosomal number.
Meiosis 1 makes the secondary oocyte (2n) and the first polar body - done at ovulation. Second polar body will be shed on fertilisation to make the egg 1n.
What are the hormone ‘stages’ for reproductive hormones?
Hypothalamus - kisspeptin stimulates GnRH release.
Anterior Pituitary: GnRH stimulates LH and FSH.
LH will do the Leydig cells in men and the Theca cells in women.
FSH will do the Sertoli cells in men and the granulosa cells in women.
What is the path of sperm?
Testes –> Semeniferous tubules –> epydydimis (storage) –> ductus deferens (vas deferens) –> through prostate into urethra and up through corpus spongiosum.
Which 3 cell types do I need to know if the Seminiferous tubes and which layer are they in? What do these cells do?
Spermatogonia - progenitor cells for sperm
Sertoli cells - support sperm, make liquid to help them move, provide nutrients - in the same epithelial layer as the spermatogonia.
Leydig cells - in the outside interstitial layer - make testosterone after puberty.
What is Androgen Binding Protein and what does it do?
A molecule made by Sertoli cells to keep testosterone at a good level in the testes.
What feedback pathways are available in male reproduction?
All negative.
-Testosterone will turn off GnRH and LH/FSH.
-Inhibin from Sertoli cells will turn off FSH.
How many oocytes are made from a single follicle?
ONLY EVER 1
List the basic layers of the follicle in order
Innermost is the oocyte, then the granulosa cells, then the theca cells, then the surface epithelium.
When is a follicle mature?
It completes meiosis 1 and makes the first polar body (first ovulation).
What do Theca cells do and what do granulosa cells do?
Theca cells - make androgens
Granulosa cells - use aromatase to make estrogen
What are the 3 stages of the ovarian cycle?
- follicular phase, ovulation, luteal phase.
What happens in the follicular phase and what hormones are important?
Day 0-13.
All starts with FSH. FSH does granulosa cells, so they will start making estrogen.
Estrogen will inhibit LH/FSH from the pituitary but will have a positive feedback on the granulosa themselves.
FOLLICLE IS INDEPENDANT ESTROGEN FACTORY.
Note - one follicle will become dominant by using estrogen and inhibin to downregulate FSH to kill other active follicles.
What happens during ovulation and what hormones are important?
DAY 14.
Very high estrogen has built up.
LH and FSH surge due to progesterone levels having modestly built up).
Primary oocyte completes meiosis 1.
Egg breaks free and starts its journey after giving off its first polar body.
What happens during the luteal phase and what hormones are important?
Day 15-28.
It’s mostly a game of progesterone.
The leftover follicular granulosa cells become the corpus luteum and becomes a progesterone factory.
Progesterone and estrogen grow the endometrium and inhibit virtually every other hormone.
These levels will be maintained if fertilised, if not, the corpus luteum will degrade and LH and FSH will rise again, restarting the process.
What are the uterine phases?
-Menses
- Proliferative phase (follicle developing)
- Secretory phase (starts at ovulation) - temp rises.
What functions does semen have besides carrying sperm?
- Neutralises the vaginal acid.
- it is pro-coagulatory to help sperm climb
- Prostaglandins to reduce cervical mucosal thickness
- has anti-immune properties
Which 3 structures create the semen?
- Seminal vesicles - sperm motility, ph, fructose.
- Prostate - enzymes
- Bulbourethral glands
What changes happen during ejaculation and what nerve system is involved.
Parasympathetic for erection (vasodilates and compresses veins).
Sympathetic for ejaculation.
Bladder sphincter contracts to prevent backflow.
Ducts contract to release semen.
Peristalsis of urethral tissues.
RESOLUTION PHASE
What features of sperm specifically help it in fertilisation?
CAPACITATION
Enzymes in sperm head to erode egg.
Cortical reaction to prevent polyspermy
- there is only ever one sperm per egg. EVER.
Name 3 extra-embyronal features of a pregnancy.
Trophoblast becomes chorion, which becomes placenta.
Amnion is fluid.
Allantois becomes umbilical cord.
Where is HCG made?
In the chorion
Does the mum’s blood mix with the baby’s?
No. The Decidua of the endometrium is very close to the chorionic vessels of the placenta which allows for exchange without touching.
Which area takes on the role of the corpus lutuem as the estrogen/progesterone factory during pregnancy?
Chorion.
Which hormone lowers mum’s glucose use during pregnancy?
Relaxin - so baby can use glucose.
What are the 3 stages of pregnancy, when do they occur and what are the biggest risks during these periods?
- Early pregnancy (1-2 weeks).
- not susceptible to teratogens
- very susceptible to chromosomal/implantation issues - Embyronic stage (3-8 weeks)
- MOST susceptible to teratogens - Fetal stage -to term
- only minor abnormalities occur
Aside from cardio features, what other physiological changes occur during pregnancy?
Hunger but constipation, greater tidal wave in resp, GFR up in kidneys.
Which hormones prevent and promote first contractions?
Progesterone prevents, estrogen promotes.
High progesterone prevents early contractions.
Explain how contractions begin?
Baby drops low in uterus and pushes on cervix, stretching releases oxytocin which as positive feedback for contractions.
Which hormones grow breasts, create milk and release milk.
Estrogen grows boobs, prolactin makes milk, oxytocin releases milk.
Both estrogen and progesterone block prolactin - don’t need milk during pregnancy.
What are the symptoms of an enlarged prostate?
Hesitancy, poor flow, poor emptying, double voiding, nocturia, frequency.
If bad - acute urinary retention.
Compare BPH to Prostatic adenocarcinoma on histology.
Both are prostatic glandular tissue.
BPH shows enlarged glands and lumens.
The basal layer of the glands will still be present.
Prostatic adenocarcinoma shows smaller than usual ducts, like donuts. The basal layer will be absent.
What are the typical locations of BPH vs prostatic adenocarcinoma and how does this impact the digital rectal exam?
BPE tends to grow peri-urethral - so it impacts urination more and won’t be felt on a rectal exam.
Carcinoma tends to grow peripherally, so it is often felt on rectal exam.
Where does metastatic prostate cancer love to go?
Loves to form sclerosing lesions in bone.
Which infections can cause epidydmo-orchitis?
In kids - mumps
In young adults - chlamydia and gonnorhea
In adults - E.coli, Pseudomonas due to obstruction.
