Scenario 21 Flashcards
What are the three layers of the uterus?
Serosa (parietal peritoneum), myometrium and endometrium
How is the cervix alkaline?
Constantly producing mucus
How does the vagina protect itself?
Rich in glycogen which attract bacteria that produce lactic acid
At what angle is the vagina at?
15 degrees backwards
How does the uterus lie?
Anteversed and antiflexed
What is the broad ligament?
A double fold of peritoneum draped over the uterus and its tubes
What are the suspensory ligaments?
Continuation fo the broad ligament onto the lateral pelvic walls
What is the round ligament?
distal part of the gubernaculum around the bladder
What are the cervical ligaments?
Pubocervical, transverse cervical and sacrocervical ligaments
Where is fertilisation most likely to happen?
Ampulla
Nerves to the female reproductive system
Symp T10-L1, Parasymp S2-4 Somatics Pudendal
Arterial supply to the area
Internal iliac arteries and ovarian arteries from AA at L2
When do we have our maximum number of primary oocytes?
23 weeks- 7 million
What does the primary oocyte number reduce to by birth?
2 million and 0.5-1 million by first menstrual cycle
What are the three ovarian cycle phases?
Follicular, ovulation and luteal
What are the three uterine cycle phases
Menstrual proliferative and secretory
What hormones are high in menstrual stage (first part of follicular)?
FSH and LH
FSH causes 20 antral follicles to be recruites with one becoming the Graafian follicle
Why does one of these follicle become dominant?
FSH causes the proliferation of granulosa cells in the follicles and LH receptors to be expressed on these cells by 10 days one follicle will be dominant and secrete oestrogen which causes a reduction in FSH levels causing atresia of the other non dominant follicles
What hormones are present in the proliferative phase (second part of follicular) day 6-14
FSH, Oestrogen (LH dropped)
What is the result of the production of oestrogen from the graafian follicle on the uterus?
Formation of a new endometrial layer and spiral arteries and cervix produces mucus to reduce the acidity of the vagina
What happens at ovulation?
LH levels rise and 36 hours after the graafian follicle ruptures and discharges an oocyte
What hormones are high in the secretory/ luteal phase?
Progesterone and oestrogen, FSH and LH dropping
How does the graafian follicle transform into the corpus luteum?
Remaining FSH and LH
What is the role of progesterone?
Makes the endometrium respond to implantation by causing the endometrial glands to secrete mucus and glycogen
Why do FSH and LH levels drop?
Suppressed by the progesterone and oestrogen from the corpus luteum
What happens to the CL as FSH and LH drop
Atrophy and death unless fertilisation occurs and hCG is produced which is structurally similar to LH meaning it can continue to make progesterone and oestrogen for 10-12 weeks until the placenta takes over
When does menstruation happen?
When the CL degenerates and oestrogen and progesterone levels drop- uterine gland are wide and spiral arteries start contracting
What does a small increase of oestrogen do?
decrease in FSH production
What does a large increase in oestrogen do?
increase LH production (late follicular phase)
How do we measure ovarian reserve?
1-antral follicle count (in early follicular phase)
Hormone levels- inhibitin B suppression of FSH secretion decreases so high FSH in early follicular phase, anti-mullerian hormone
What is the superficial fascia surrounding the external genetalia?
Colles
What is the smooth muscle surrounding the external genitalia?
Dartos muscle
What is the deep fascia over the penis?
Bucks
What is the contents of the spermatic cord?
3 arteries- testicular, cremasteric and ductus deferens
3 veins- pampiniform plexus, cremasteric, ductus deferens
3 nerves- autonomics (symp T10-11), genitofemoral (cremaster) and ilioinguinal
3 other things- ductus vas deferens, lymphatics and processus vaginalis remnant
3 layers- external fascia, cremasteric and internal spermatic fascia
How are the reproductive organs aroused?
Parasympathetics- pudendal nerve(S3)
How does ejaculation occur?
Phase 1- contraction of SM in wall of epididymis and vasa differentia of testes to peristaltically move spermatozoa to prostatic urethra where sympathetic stimulation causes sperm to be mixed with secretions from prostate and seminal vesicals (urethral sphincter closes)
Phase 2- contraction of skeletal muscle to pump semen down urethra
Where is the lymphatic drainage of the superficial perineum?
Superficial inguinal nodes
Where is the lymphatic drainage of the testes epididymis and the ductus deferens?
Para aortic nodes around L2
What is the arterial supply to the testes?
testicular arteries from AA at L2 through deep IR and into spermatic cord
Ductus deferens is supplied by the deferential artery
What is the venous drainage of the testes
Pampiniform plexus which forms a single testicular vein on the right to IVC at right and on the left joining left renal vein
What happens in the epididymis?
Sperm are concentrated
What is the role of the seminal fluid from the seminal vesicles?
Protein rich and high fructose to give the sperm energy. Prostaglandins to open the cervix and alkaline to neutralise the vagina
Where are the bulbourethral glands and what do they do?
In deep peroneal pouch and secrete mucus to lubricate the urethra (pierce at bulbous urethra)
What is the role of the prostate gland?
Contributes citric acid to seminal fluid and secretes proteolytic enzymes for phospholipid metabolism for maintenence of the sperm.
What is the lymphatic drainage of the prostate?
Para aortic nodes and cystera chyli cancer can also spread in venous plexus
Where in the ovaries are the follicles?
Outer cortex
What are the ovaries covered in?
Germinal epithelium and tunica albuginea
How are primary follicles formed before puberty?
Activated primordial follicles
How do these primary follicles become secondary follicles?
Flattened follicular cells become cuboidal and proliferate to give the zona glomerulosa and englarge and get surrounded in a glycoprotein coat (zona pellucida) the theca folliculi is formed and differentiates into theca interna and theca externa. Antrum forms in zona gomerulosa
What is the function of the theca interna?
Maked steroid hormones
What oocyte does the secondary follicle contain?
Primary oocyte
What happens when the monthly cycle starts?
FSH triggers 20 follicles to develop further, LH rises and stimulates theca interna to make oestrogen which suppresses FSH and only the Graafian follicle survives
What happens mid cycle when LH rises?
primary oocyte completes meiosis 1 and forms a secondary oocyte arrested at metaphase of meiosis 2
What happens at ovulation?
Follicle ruptures discharging secondary oocyte
What happens to the follicle after ovulation?
Collapses and granulosa cells form corpus luteum
What does the corpus luteum secrete?
Oestrogen and progesterone which suppress FSH and LH
Why does the corpus luteum degenerate?
No LH
What are the key features of the uterine tube?
Highly convoluted mucosa, inner circular and outer longitudinal muscle layers and simple columnar epithelium containing ciliated and secretory peg cells
What are the layers of the endometrium?
Stratum basilis which persists and stratum functionalis which is lost with menstruation
What is the epithelium transition at the cervix?
From the simple columnar of the uterus to the stratified squamous of the vagina
How many lobules are in the testes and how many seminiferous tubes to each?
400 and 1-4 tubes to each
Where do the seminiferous tubes drain to?
Rete testes and epididymis
Where are the gametes formed\?
Seminiferous tubules
What do spermatogonia give rise to?
Type A (condensed chromatin) which undergo a limited no of mitoses creating clones and Type B (more dispersed chromatin) which complete mitosis and enter meiosis as primary spermatocytes
When does crossing of homologous chromosomes take place?
in prophase of first meiotic division
What are secondary spermatocytes?
After the first meiotic division- 2 daughter cells, they enter the second meiotic division
What are spermatids?
The haploid daughter cells after two rounds of meiosis
How do spermatids form spermatozoa?
condensation of the nucleus, formation of the acrosome, formation of the flagellum, shedding of unwanted cytoplasm (6 weeks)
What is the role of Sertoli cells?
Mechanical and nutritive support for the developing spermatozoa,, generate the blood testis barrier, injest unwanted cytoplasm, produce testicular fluids and secrete androgen binding proteins to concentrate testosterone
Where are Leydig cells found and what is their role?
Between seminiferous tubules and produce testosterone in response to LH
What are the walls of the epididymis made up of?
Smooth muscle and tall pseudostratified epithelium
What are the 4 zones of the prostate?
Transition zone around prostatic urethra, central zone where ejaculatory ducts are, peripheral zone where cancer occurs and anterior fibromuscular stroma
What are the two compartments of the testicles and what are the separated by?
Leydig cells and basal layer of germinal epithelium lining seminiferous tubules are one compartment and the other is the superficial layers of germinal epithelium and sertoli cells.
Separated by the blood brain barrier
What are the main functions of the blood testicular barrier?
Prevents leakage of spermatozoa into the circulation and risking anti-sperm antibodies forming, also maintains a unique chemical environment in the seminiferous tubules
What are the roles of FSH and LH in sperm production?
FSH binds to receptors on the epithelium of seminiferous tubules stimulating stem cells and sertoli cells to produce sperm
LH binds to Leydig cells to increase testosterone production
Does testosterone inhibit or stimulate FSH and LH?
inhibit
What is capacitation?
Happens in the female reproductive tract by the influence of calcium and bicarbonate, increases cAMP causes hyperactivation, acrosome reaction (digestion of zona pellucid) and release of cortical granules to block polyspermy
What could cause abnormal testicular function?
Genetics (kleinfelter, kallman syndrome), androgen receptor defect or environmental factors like steroid hormone abuse, infection or polllution
What % of semen is retained by the cervix?
1%
What are the contents of semen?
Ejaculate, alkaline, prostatic secretion (acid phosphatase), seminal vesicle fluid (high in fructose), prostaglandins
>1.5ml, 40% motility and morphology >4% normal
What happens to the blastocyst after implantation (day 6)
Outer trophoblast divides to form cytotrophoblast (ecto, meso and endoderm) and synctiotrophoblast (placenta) and the blastocytic cavity (spinal cord and CNS system)
Why do women put on variable amounts of weight in pregnancy?
Variable ECF gain
Why does hemarocrit fall in pregnancy?
Red cell mass increases but ECF increases more so dilutional anaemia 40-32%
By how much does 2-3-diphosphoglycerate increase?
30%
Do lipids increase or decrease?
Increase due to maternal oestrogens and cholesterol synthesis for placental hormone
How much folate should be taken and why?
400 micrograms/day and to help with neural tube closure
What is the role of oestrogen in pregnancy?
Stimulates synthesis of liver FAs and cholesterol
CV adaption to pregnancy- dilation of BV
Growth and remodelling of the uterus (increase gap junctions)
Weak anti-insulin activity (more glucose available for fetus)
What is the role of progesterone in pregnancy?
Prepares and maintains endometrium (reduces excitability and prevents cervix ripening)
Suppresses maternal immunological response to fetal antigens
Partutition
Growth of mammary glands
Stimulates RAAS
What is the role of human placental lactogen?
FA metabolism
When is PIGF low?
Pre-eclampsia
What is the role of leptin?
Placental AA/FA transport
What are the CV adaptions to pregnancy
Decreased BP due to vasodilation but also rise in CO and heart rate
Why does TVPR fall?
Increased NO synthesis, increased prostacyclin synthesis, relaxin
What is the effect of pregnancy on GFR?
huge increase allowing clearence of waste but osmolarity of the blood falls (doesnt leas to diuresis)
What happens to tidal volume in pregnancy?
increases
How does the endometrium change to receive the embryo?
Rich in glands, capillaries and stroma, cytokine signalling and cellular outbranches from epithelium to facilitate attachment
What does penetration involve?
Prostaglandins
What is required of the maternal circulation?
enlarged stromal and NK cells to alter the uterine spiral arteries
When do the spiral arteries open?
12 weeks
What may result of them opening too early/ too late?
Late- fetal growth restriction, pre eclampsia
Early, miscarriage implantation failure, oxidative stress leading to malformations
What is the incidence of monozygotic twinning?
3/1000
What makes monozygottic twins dichorionic?
Cleavage before implantation
What makes monozygotic twins diamniotic?
Cleavage day 6-8 (monochorionic)
What makes twins monoamniotic
Cleavage after day 8
What is the incidence of dizygotic twinning?
6/1000
What feature characterises the end of the second week?
Chorionic villi
What causes the placenta to regress?
Oxidative stress causes apoptosis of outer cells from the spiral arteries
What are the functions of the placenta?
Respiratory organ, nutrient transfer, excretion of fetal waste products, hormone synthesis
What are terminal villi?
Small buds of chorionic villi which are the site of nutrient transfer
Which has a higher oxygen concentration? fetal placental artery or vein?
Vein (still lower than adults)
What is system A for AA uptake?
Uptake of small non essential neural AAs (alanine, glycine and serine) contributing to a high intracellular conc of these inside the cell
Mainly SNAT1
Stimulated by insulin, IL6 and TNF alpha
What is System L for AA uptake?
Sodium independent exchanger of neutral AAs from system A for essential AAs such as leucine or phenylalanine against their conc gdt
mTOR is a positive regulator
What is the taurine system for AA uptake?
taurine uptake against its conc gdt by co transport with sodium and chlorine
How is glucose transported across the placenta?
facilitated carrier mediated diffusion through GLUTs down conc gdt (mainly GLUT 1)
How are FAs transported across the membrane?
LPL facilitated release of NEFAs from triglycerides which are transported by FA transport proteins
At how many weeks are the gastric hormones and villi present?
13 (gastrin, motilin and somatostatin) and 16 (swallowing amniotic fluid)
How much urine is produced by a fetus per day?
0.5L bladder empties every 30 mins
What is the GFR of a fetus?
50% of adults
What is the amniotic fluid volume?
50ml 12 weeks to 1000ml, 500ml exchanged every 24 hours
What are the contents of amniotic fluid?
urine, amniotic membrane secretions, fetal lung secretions, salivary secretions, fetal epithelial cells, amniotic cells, dermal fibroblasts
What are the fetal membranes?
Amnion and chorion
What is the role of the amnion?
Filled with fluid, protects fetus from trauma, allows movement,, separates fetus from fetal membranes, facilitates symmetrical growth, serves as a source of oral fluid and an excretion and collecting system
What is the role of the chorion?
In and through which the major branching umbilical vessels travel on the surface of the placenta
What controls feta heart rate?
Parasympathetic tone q
What is surfactant made up of and when is it excreted?
phospohlipids, protein, cholesterol, secreted from 30 weeks reduces surface tension
Why is HbF different to HbA?
Higher affinity to oxygen due to a lower sensitivity to 2-3-DPG
How are the lungs cleared in labour?
Physically squeezed, ENaC activated and transpulmonary hydrostatic pressure gradient
What are the sexual differences in the pelvis?
Cavity wider in females and oval shaped (heart in males), infra pubic angle is obtuse in females (acute in males), distance from acetabulum to pubic symphysis is greater than the width of the acetabulum in females
What 4 forms of pelvis are there?
Gynaecoid (female form)
Android (male form) Anthropoid (able to engage if baby in AP direction) longer sacrum to ps distance, platypoid wider (able to engage if baby in transverse direction)
How does a baby usually engage?
In a transverse direction then rotate to be AP
What does the deep perineal pouch contain?
part of the urethra, external urethral sphincter (in males bulbourthral glands and deep transverse perineal muscles)
What does the superficial perineal pouch contain?
Erectile tissues, ischiocavernosus, bulbospongiosus and superficial transverse perineal muscles and greater vestibular glands
What are the pelvic floor muscles?
Levator ani- puborectalis, pubococcygeas and iliococcygeas
What is the innervation to the pelvic floor muscles?
Perineal branch of S4 and pudendal nerve
What are the corpus cavernosa?
Have a crus and longer in males and form the clitoris in females
What are the superficial muscles?
Bulb of penis and vestibule are covered by bulbosponiosus and corpus cavernosa covered by ischiocaernosus
Also a pair of superficial transverse muscles which contract to to compress the bulbourethral glands
What is the course of the pudendal nerve?
winds around ischial spine (targeted in labour) passing out of greater sciatic foramen and into lesser then along border of obturator internus
What is the vasculature of the perineum
Branches of the internal pudendal artery giving off branches- perineal, bulb of penis, deep artery of penis, dorsal artery of penis
Which part of the penis enlarges during erection?
Corpus cavernosum (urethra runs through the spongiosum) Parasymp then symp
Where is breast cancer usually found?
Upper left quadrant near axilla
What are the lumps created by sebaceous glands called?
Montgomerys tubercles
What is the nerve supply to the breast?
Cutaneous branches of 2nd-6th IC nerves
What is the blood supply to the breast?
Mostly lateral thoracic artery but also internal thoracic, thoracoacromial and posterior intercostals
What is the lymphatic drainage of the breast?
75% axilla 25% internal thoracic chain
What are the common breast cancer signs?
Nipple retraction, nipple bleeding, oedema and therefore skin dimples (peau d’orange) from retraction of coopers lig
Where are common sites for metastasis?
Lungs, skeletal system and liver
How does the cervix ripen?
An inflammatory process cytokines induce iNOS and COX-2 leading to NO and PGE2 production activating MMP2 and 9 which affect collagen fibre integrity
Cervical distension triggers oxytocin release and PG production
How is the myometrium activated?
Induction of CAPS (contractile associated proteins), calcium conc within the cell increases via ion channels and IP3 releases more from SR, RMP increases so more contractions through gap junctions
Uterus primed to respond to oxytocin and PG
Are gap junctions unregulated?
Yes
How does oxytocin sensitivity change?
Increases and increased expression of the oxytocin receptor
What happens to progesterone?
Rises through pregnancy then plateaus causing a functional loss
What are they hypotheses for what decides the timings of birth?
Placental CRH production, Fetal HPA, cortisol and PGE2 plus a drive for oestrogen production (From DHEAS) play a key role, functional progesterone withdrawal, fetal maturation initiates surfactant which stim inflamm response, increasing cytokine output and suppressing progesterone
Why does lactation not occur until post partum?
Need oestrogen and progesterone withdrawal for prolactin to respond.
How does suckling produce milk?
Neuroendocrine reflex- suckling stimulates VIP from hypothal which causes PRL synthesis in ant pit and inhibits dopamine release. Strength and duration of suckling determines subsequent PRL production
What is the milk ejection reflex?
Suckling signals to the hypothalamus to produce and release oxytocin which stimulates myowpithelial cells around lobules to contract and push milk into ducts.
