GEP (Life Cycle week 3) Flashcards
What is the blood supply, lymphatic and innervation of the: Vulva, Vagina, Uterus, Uterine tubes, Ovaries
Ovarian arteries arise directly from abdominal aorta at L2
Uterine artery (supplies uterus and cervix) and anastamoses with ovarian artery
Pudendal artery- supplies vulva, arises from internal iliac
Identify these anatomical marks
Desribe the venous drainage system of the female reproductive system
- Generally follows arterial supply
- Uterus and uterine tubes drain into uterine veins -> internal iliac veins
- Vagina drains into vaginal plexus-> uterine veins-> internal iliac veins
- Vulva drains into pudendal veins-> internal iliac veins
- Ovaries drain into ovarian veins
- Right-> IVC
- Left-> left renal vein
N.B. testicular veins follow same pattern
Where is the ureter anatomically to the arteries
Ureter runs under the uterine artery
‘Water under the bridge’
Significant in surgeries eg hysterectomy when ureter could get damaged
Describe the lymphatics of the female reproductive system
IILN: internal illiac lymph nodes
EILN: External illiac lymph nodes
What are the sensory nerve supply to the female reproductive organs
Early labour pains are therefore transmitted to T10-L1 spinal roots
Late labour pains are transmitted to S2-S4 spinal roots
Pudendal nerve supplies the majority of the vulva
Give an overview of ovulation
LH surge leads to release of dominant follicle
Follicular cells release digestive enzymes that make a hole in the ovary wall
Released into the peritoneal cavity
Fimbrae sweep oocyte into peritoneal cavity
Oocyte is moved down the tubes by peristalsis and cilia
! LH surge stimulates completion of first meiotic division !
Corpus Luteum
Granulosa and theca cells left behind
Luteal cells have MANY LH receptors so survive and continue to produce progesterone when there is a drop
After 14 days the CL will die off (unless kept alive by BhCG released by syncytiotrophoblasts)
Describe the process of fertilisation
- Uterine contractions force the sperm and egg together
- Sperm follows the cytokine gradient released by the egg (site of fertilisation most commonly ampulla)
- Sperm binds to glycoproteins on the zona pelucida- causes reaction of acrosome (tip of the head)
-Calcium floods into sperm
-Release of hydrolytic and proteolytic enzymes
-Fusion of genetic material (23 chromosomes from egg + 23 from sperm = zygote) - Sperm fuses with the oocyte membrane causing calcium release from smooth endoplasmic reticulum of egg
-Stimulates the egg to finish meiosis 2
-Makes oocyte more positive meaning sperm can’t bind -> primary block (fast) - Increase in calcium causes exocytosis of cortical granules, causes hardening of membrane -> secondary block (slow)
- Blocks prevent polyspermy
What is sperm capacitation
Sperm capacitation
Triggered by uterine secretions
Cholesterol removed from membrane-> increased fluidity
Proteins in head membrane activated
Increased cation channels in flagellum activated-> more strength and speed to get to egg
What are the differences between oogenesis and Spermatogenesis
Meiosis in men produces 4 haploid sperm
Meiosis in women produces 1 ovum and 2 polar bodies
Remember- second meiotic division only happens when fertilised
What is the process of forming a blastocyst
Day 4-> 5 = morula-> blastocyst
What does the inner cell, blastocoel and trophoblasts become
Inner cell mass: develops into foetus
Blastocoel: fluid filled cavity that develops into the yolk sac
Trophoblasts: become foetal placenta
What is hatching in regards to fertilisation
hatching happens roughly at day 7
Loss of zona pelucida
Essential for implantation (happens 6-10 days after ovulation)
If this happens while the zygote is still in the tubes then at risk of ectopic pregnancy
What is Decidualisation
Decidualisation
Progesterone from corpus luteum stimulates functional changes in the endometrium to facilitate implantation
Cells of endometrium become modified with lipids and glycogen
Decidual orms maternal part of the placenta
What happens in the process of implantation
- On implantation, trophoblasts differentiate into cytotrophoblasts and syncytiotrophoblasts
- Syncytiotrophoblasts burrow into endometrium and lose their cell membranes forming rapidly growing multinucleate cell mass
- Produce BhCG!
- Cytotrophoblasts follow, still have individual cells
- Blood vessels grow from the mesoderm
- Invading bits (mesenchymal villus) become more convoluted and so increase the surface area
- mesoderm + cytotrophoblasts= chorion
- Lacunae (pools of mothers blood) form and mingle with villi- from spiral arteries
-Diffusion between the two, across the syncytiotrophoblast membrane
What is gastrulation
- Gastrulation is a critical process during week 3 of human development. Gastrulation is an early developmental process in which an embryo transforms from a one-dimensional layer of epithelial cells, a blastula, and reorganizes into a multilayered and multidimensional structure called the gastrula.
Blastula (2 layers- epiblast + hypoblast) become gastrula (3 germ layers)
Epiblast forms amniotic sac, hypoblast forms yolk sac
Occurs at day 16 resulting in ectoderm, mesoderm, endoderm
BhCG
Released by trophoblasts after bound to the endometrium
CL hormones vital before placental steroidogenesis (7 weeks)
Serum hCG helps monitor early complications eg if it drops when it shouldn’t
Peaks 9-11 weeks
How do you daignose Pregnancy
Signs & Symptoms
Missed period
Fatigue
Swollen/tender breasts
Spotting (implantation bleed)
Cramping
Headaches
Nausea
Strange tastes, smells, cravings
Urine pregnancy test - β-hCG
* Produced from syncytiotrophoblast at implantation (day 7)
* Doubles every 48 hours until 8-12 weeks, where it gradually declines
What is ectopic pregnancy
Implantation of a fertilised ovum outside of the uterus. Most commonly occurs in the ampulla of the uterine tube
Signs & Symptoms
Often start around 6-8 weeks after last period
Pain
Vaginal bleeding
Hemodynamically unstable
Cervical tenderness
Diagnosis
Urine/serum beta-hCG
Abdominal or transvaginal ultrasound
Management
Methotrexate
Surgery
Pain worsens with movement or sexual intercourse
Bleeding may be heavier or lighter, an may have clots. Different to usual menstrual bleeding
Ruptured can cause shoulder tip pain, haemodynamically unstable
Slower rising hCG levels compared to normal pregnancy
What are the 6 key hormones in pregnancy
What are the theories that initiate labour
Progesterone Withdrawal
Decrease in muscle relaxant effect
Oestrogen becomes dominant
❔Cervical Pressure
Pressure on the cervix signals brain to
release oxytocin
❔CRH Placental Clock
CRH released from the placenta
determines the length of pregnancy
❔Cervical Inflammation
Release of prostaglandins encourages
contractions
Describe the process of labour using the 3P’s
Passenger
Passage
Power
Explain the first stage of labour
Latent
First stage of labour
Initial stage of cervical dilation (~4 cm) and effacement (3 cm → 0.5 cm long)
Contractions often irregular and mild/moderate in pain
Can last very long time, particularly in primigravidas
Active
Duration for the cervix to dilate from 4 to 10 cm
Contractions become more regular, longer lasting and more intense
Contractions lasting 45-60 secs, every 3-5 mins
What is the bishops score
The Bishop score reflects the normal changes the cervix undergoes in parturition (the process of childbirth). Extensive cervical remodeling is needed for the cervix to dilate and pass a fetus fully.
Explain the second stage of labour
From full cervical dilation to delivery of the neonate
~ 1 hour in primigravida and ~30 minutes in multigravida
Head flexion allows the baby’s vertex to descend through the maternal pelvis
Internal rotation of the head travelling down the vagina
Head delivered (either facing mothers thigh or towards her perineum)
Shoulders rotate and each arm delivered individually
Rest of the baby is delivered, still attached to the placenta (which remains in utero
Delivery may be assisted with:
▸Episiotomy
▸Instrumental (forceps or suction)
▸Caesarean section (elective/emergency)
Explain the third stage of labour
Begins immediately after the birth of the baby and ends with the delivery of the placenta and foetal membranes
- Placenta detaches from the uterine wall ~15 mins after delivery of the baby, delivered with traction on the umbilical cord and gentle pushes from mother
- IM syntometrine given to help placenta detach and deliver
- Placenta and membranes should be assessed post delivery to check is complete
Patient should be assessed for any perineal tears and estimated blood loss
What are the labour complications
During Delivery
Foetal distress (pathological CTG/bradycardia)
Failure to progress
Malposition
Uterine rupture
Cord prolapse
Shoulder dystocia
Placental abruption
Amniotic fluid embolism
Perineal tears
Post Delivery
Retained placenta
Postpartum haemorrhage (PPH)
Major obstetric haemorrhage (MOH)
What is puerperium
The postpartum (puerperium) is defined as the 6-week period of time beginning immediately after birth, during which the reproductive organs and maternal physiology return toward the pre-pregnant state.
What is lactation and how does it occcur
- Raised oestrogen and progesterone during pregnancy cause breast development, but have inhibitory effects on prolactin secretion
- Stimulation from the baby suckling at the nipple stimulate brain, and prolactin is released from anterior pituitary, while oxytocin is released from the posterior pituitary
- Prolactin causes lactogenesis in mammary glands
- Oxytocin causes contraction of myoepithelial cells in alveoli/ducts to contract and eject milk
Colostrum: first 48 hours, provides passive immunity to baby (IgA)
Mature Milk: days 3-4, ↑cholesterol & fat
