Learning Outcomes (Non-CLIC) Flashcards
Define Oogenesis.
The process by which female gametes/Ova(um) are created
or
The steps/process a developing egg (oocyte) goes through to differentiate into a mature egg (ovum).
Each gamete = haploid = one copy of each chromosome)
Describe Oogenesis.
Phase 1 (during foetal development and before birth):
1- Oogonia are created
2- undergo mitosis -> millions produced
3- Oogonia also begins to differentiate into primary oocytes
4- millions degenerate and die before birth
5- the remaining enter meiosis I
6- meiotic arrest occurs in prophase I
Phase 2 (occurs at ovulation hence it begins at puberty with menstrual cycle developing one primary oocyte into a secondary oocyte)
1- When menstrual cycle takes place primary oocyte finishes off meiosis I producing secondary oocyte and a polar body (this is stimulated by LH)
2- secondary oocyte begins meiosis II and meiotic arrest occurs in metaphase II
3- Secondary oocyte is ovulated
4- Sperm comes along and fertilizes it
5- On fertilisation meiosis II is completed and you have an ovum
Remember: Oogenesis begins before birth and finishes after secondary oocyte is ovulated
What are oogonia?
Oogonia are germ cells. Germ cells are cells that create reproductive cells called gametes in humans.
Describe Follicular Development.
Note: follicular development is independent from oogenesis but parallel to it.
1- Primordial Follicle - single layer of granulosa cells around the oogonium (This is a small follicle - most numerous at any one point, secrete anti-mullerian hormone)
2- Primary Follicle - this surrounds the primary oocyte, the oocyte size continues to increase, the layer of granulosa cells increase and three layers are created (this is occurring parallel to the increase in size of oocyte), separated from oocyte by zona pellucida but gap junctions allow nutrients to reach the oocyte
(GROWTH FROM SMALL TO MEDIUM IS INDEPENDENT OF HORMONES)
3- Early antral follicle - this is just before pre-ovulatory follicle, here the antrum began to form as fluid is secreted from granulosa cell, and there is granulaosa cells which have differentiated into theca cells
4- Pre-ovulatory (mature) follicle - this has the secondary oocyte in it arrested in meiosis II, and Antrum fully formed
(Primary Oocyte develops into secondary oocyte same time primary follicle becomes pre-antral -> early antral -> Pre-ovulatory (this also named graafian follicle which means follicle with developed antrum)
Define small, medium, and large follicles.
Small = primordial follicles Medium = this is primary and pre-antral follicle Large = Graafian Follicle (rapid mitotic divison to get to this stage and antrum fills with fluid)
Describe the difference between the growth of small follicles to medium, and medium to large.
- Small -> medium = independent of hormones
- medium -> large = stimulated by FSH and takes 14 days
A) Which hormone stimulate Theca cells to produce androstenedione?
B) what is androstenedione the precursor to?
A) LH
B) precursor to the synthesis of estridol 17 Beta
List the two gonadatropins and two gonadal sex hormones.
1) LH and FSH (Anterior Pituitary Gonadotropins)
2) Oestrogen and progesterone
Describe how the corpus Luteum is created.
- Mature follicle releases it Antrum and egg
- Granulosa cells and theca cells enlarge and form gland-like structure ie the corprus luteum (if no fertilization will reach maximum development within 10 days and degenerate by apoptosis)
Name the hormones secreted by Corpus Luteum.
- Oestrogen
- Progesterone
- Inhibin
What is the role of LH in the ovulation process when it surges and triggers ovulation?
- Induces prostaglandins endoperoxide synthase in granulosa cells (setting up a pseudo-inflammatory response)
What is the role of FSH in ovulation?
Stimulates plasminogen activator from granulosa cells (Plasminogen –> plasmin)
Describe the role of Prostaglandins E and F in ovulation.
Release lysosomal enzymes which digest the follicular wall
Describe the role of Stigma in Ovulation.
- Stigma is the area of the ovary surface where the follicle exits/burst out
- Forms on the surface of a follicle, balloons out, forms a vesicle then ruptures –> oocyte expelled
Compare and contrast Spermatogenesis and oogenesis.
Spermatogenesis:
- Continuous Process
- Lower temperature is required
- Meiotic Spermatogonia proliferation begins after puberty (indirectly dependent on progesterone)
- The meiotic division of one primary spermatocyte produces 4 mature spermatozoa
- This process results in the production of an infinite number of sperm
- Results in the production of motile gametes
- Products of meiosis (spermatids) undergo considerable differentiation while maturing and becoming spermatozoa
Oogenesis:
- Discontinuous process
- Normal body temperature
- Meiotic proliferation of oogonia occurs prior to birth
- Meiotic division of oocyte produces one mature ovum
- second meiosis complete upon fertilisation
- results in the production of a finite number of oocytes
- Results in the production of immotile gametes
Name the two stages of ovarian cycle.
- Follicular Phase
- Luteal Phase
What are the phases of menstrual cycle.
- Menstrual Phase
- Proliferative phase
- Secretory Phase
Following LH Peak, What happens on the following days: 1- 1 day 2- 2 days 3- 2-4 days 4- 5 days 5- 6-7 6- 9-10
1- ovulation
2- fertilisation.
3- cell division to 32 cells
4- Blastocyst enters the uterine cavity
5- implantation (attaches adjacent to the inner cell mass), here the blastocyst leaves the zona pellucida and is bathed in uterine secretions for 2 days, it is a limited attachment window
6 -Human Chorionic Gonadotropin Hormone (hCG) from implanted blastocyst (trophoblast cells) rescues corpus luteum (from the trophoblasts hCG goes to maternal ovary)
The ovarian cycle involves a _________ phase, followed by a __________ phase. In the initial phase, GnRH released by the __________ causes the anterior _________ gland to release two hormones. Once released, the _________ hormone stimulates the development of the follicles in the ovaries. The maturing follicles release _________ leading to the growth of the lining of the uterus, and a spike in the concentration of ________, which triggers ovulation. In the second phase of the ovarian cycle, the corpus luteum forms releasing mainly __________, which increases the blood, supply to the uterus, and further thicken the uterus lining with additional fluids and nutrients ready to support a developing embryo.
Follicular Luteal Hypothalamus Pituitary FSH Oestrogen LH Progesterone
Notes: Oestrogen inhibits FSH in the follicular phase
Progesterone inhibits both LH and FSH in the luteal phase once the corpus lutem degenerates progesterone decreases allowing the increase of LH and FSH once more cycle repeats
Describe how the fertilized egg under goes cell division.
1- Conceptus (Fertilized egg) is held in the fallopian tube dur to smooth muscle contraction induced by estrogen
2- Conceptus undergoes cleveage leading to the formation of the mourla (16 cells) which takes 3-4 days (could be up to 32 cells by day 4 (32-cell stage) but it would still be called the mourla)
3- All cells in the mourla totipotent
4- 4-5 days after fertilization the blastocyst is formed (Blastocyst has fluid-filled cavity, inner cell mass, and trophoblasts which is the layer that creates the round/ball structure all within the zona pellucida
Explain the difference between the following cell types:
- Totipotent Cells
- Pluripotent
- Multipotent
1- Totipotent = can form all cell types in the body including the placenta
2- Pluripotent = can give rise to all cell types excluding the placenta
3- Multipotent = develop into a limited number of cell types in a particular lineage
Describe the placenta.
Organ of exchange between the mother and fetus which develops during pregnancy
Name the cells which are of totipotent origin which give rise to the placenta found in the blastocyst.
Trophoblasts
Discuss the fate of the trophoblasts following implantation.
- They differentiate into inner cytotrophoblasts and outter layer of cells called the Syncytiotrophoblasts which invade the endometrium
- they end up creating extra embryonic tissue like the placenta and umbilical cord
What is the fate of the inner cell mass?
Fated to become the embryo, amnion, and yolk sac
In the earliest stages of the pregnancy the anatomical link between the mother, and the fetus develops through a series of phases. List those phase.
1- invasion - conceptus invades endometrium
2- Decidulisation - endometrial remodelling including secretory transformation of the uterine glands, influx of specialised uterine natural killer cells, and Vascular remodelling
3- Placentation - placenta formation
Why would a woman who has conceived with an implanted blastocyst think she is not pregnant?
- In implantation at around day 13 after fertilisation the synctiotrophoblasts of the implanted blastocyst in the wall of the endometrium erode through the walls of the large capillaries which then bleed into spaces (thi sis primitive placenta circulation) this blood bathes the synctiotrophoblasts
- This is the same time a woman expects her next period, and hence this bleed maybe thought to be the next period
Describe the process of formation of the placenta.
▪ We know that at implantation the trophoblasts differentiate into synctiotrophoblasts which erode through maternal endometrium and capillaries
▪ Digestive Enzymes break down cells and allow Trophoblasts/Synctiotrophoblasts to form villi that project into the blood filled spaces called chorionic villi (so this is bathed in maternal blood)
▪ In the core of the villus is a fetal capillary loop (this is blood vessels connected to the umbilical vein and artery)
▪ This develops over several weeks
▪ Villi become localised in the embryonic pole
▪ Huge surface area for O2 exchange
▪ Embryonic portion of the placenta is supplied from the outer most layers of trophoblast cells (ie the chorion)
▪ The maternal side of the circulation (the maternal arteries and veins that form to supply this pool of blood) is restricted and not functional until 10-12 weeks so first trimester is largely depends on uterine tissue and nutrients and O2
▪ Maternal portion is supplied by the endometrium underlying the chorion
▪ Endometrium around villi is changed by enzymes and paracrine agents so each villi is surrounded by a pool/sinus of maternal blood (Blood Sinuses)
▪ So we see that the placenta consists of chorion that forms the villi, blood sinuses bathe the chorion villi in blood, then there is the endometrium with maternal blood vessels
▪ Maternal and fetal blood are separated by The placental membrane and there is no mixing of the two bloods
List the functions of the placenta.
- Nutrition: provides nutrients (water and electrolytes (diffuse freely), glucose (facilitated diff), amino acids (active trans)) (Placental conductivity increases with weeks of gestation reaching max around 35/36 wks of gestations then declining just before parturition)
- Respiratory organ: gas exchange of O2 and CO2
- Endocrine Organ/Gland: releases hCG, Oestrogen, Progesterone
- Waste product removal: removes waste products such as CO2, Urea, and Uric Acid
- Provides Immunity: IgG immunoglobulins cross the placenta into the fetal circulation to protect them
Until the placenta can produce its own progesterone the uterus relies on the corpus luteum to produce progesterone (this is for about 13 weeks so the first trimester) to prepare and thicken uterine lining.
A) Name the hormone that ensures the corpus luteum does not degenerate and continues producing progesterone until placenta develops
B) Describe the function of that hormone
C) Name the cells that produce this hormone.
1) human Chorionic Gonadotropin Hormone
2) mimics LH, supports steroid synthesis by the CL –> prevents menstruation and any further follicular development (hCG is important in males too as it stimualtes Leydig cells to produce testesterone important for development of male duct system)
3) Synctiotrophoblast
At what point can hCG be detected by commercial kits in urine?
Sensitive kits can detect it as soon as 8 days after fertilisation
Which anatomical point reaches by the uterus during pregnancy usually marks 20 weeks of gestation?
umbilicus
Which anatomical point reached by the uterus during pregnancy usually marks 36 weeks of gestation?
xiphoid orocess
- Define the fundal height.
- What is it used for?
- Distance measured from pubic symphysis pubis to top of uterus (fundus)
- Used to estimate gestational age(E.g. at 36 weeks near the xiphoid process you expect it to be close to 36 cm)
What stimulates release of FSH and LH, and where is it produced?
Where are LH and FSH produced from?
GnRH produced in the hypothalamus
Anterior Pituitary
Describe the physiological respiratory changes during pregnancy.
1- Increase in minute ventilation due to increase in tidal volume (as oxygen consumption and CO2 production increases) and high levels of serum progesterone stimulating the respiratory centre but the respiratory rate remains the same
2- Increase in intra abdominal pressure due to increase in uterus size leads to feeling of breathlessness and hyperventialtion insome cases which can lead to respiratory alkalosis
Describe the physiological cardiovascular changes during pregnancy.
- Increase in CO as there is increase in SV and HR as more blood is required to supply the placenta
- Slight decrease in BP as there is decrease in systemic vascular resistance due to relaxant effects of progesterone on smooth muscle
- relaxation of systemic resistance also to allow blood flow to the placenta
Describe the physiological haematological changes during pregnancy.
- 40% increase in the volume of blood plasma
- 25% increase in RBC count
- net loss in the number of RBCs per unit volume of plasma –> physiological anaemia
Describe the physiological renal changes during pregnancy.
- Increased CO -> Increased renal blood flow -> increase GFR -> increased urinary frequency
- Increase in Kidney size (increase in the size of the calyces and renal pelvis) as the kidney adapts to the increased blood flow –> physiological hydronephrosis + physiological hydroureter
- progesterone effect on ureter -> relaxation -> hypomotility -> increase risk of UTIs
Describe the physiological GI changes during pregnancy.
Hormonal changes –> reduced peristalsis -> constipation and bloating + relaxation of the lower oesophageal sphincter leading to reflux and heartburn
Describe the role of hCG.
- maintain CL and release of progesterone and oestrogen -> prevents menses and causes decidua-like cells to become swollen with nutrients for blastocyst
- Anything happens to the CL before 7 weeks of gestation the pregnancy will spontaneously abort
Describe the effects of oestrogen in pregnancy.
- Effects on uterus = thickens the lining and maintains the lining of the uterus stimulating endometrium proliferation and vascularisation for nutrient supply
- effects on the breast = stimulates breast growth by stimulating stromal tissue growth (connective tissue), fat deposition and growth of mammary glands and stimulates the development of the ductile system
- during labor, it induces it = induces myometrial excitability, increases oxytocin receptors and formation of gap junctions, and promotes synthesis of prostaglandins
Describe the effects of progesterone in pregnancy.
Effects on uterus =
- leads to the growth/thickening and maintenance of uterus lining
- promotes development of decidua in the endometrium which is thick layer of modified mucous membrane which lines uterus during pregnancy (decidulisation = process by which endometrial cells change in structure to form decidua which supports the attachment of the placenta and implantation of the embryo , these cells become swollen with nutrients for the embryo)
- progesterone inhibits uterine contractions by
1. Inhibiting production of prostaglandins
2. Decreasing sensitivity to oxytocin
stimulates development of lobules and alveoli
Effects on the breasts:
- prepares breasts for lactation as it stimulates the development of lobules and alveoli
Describe the effects of human somatomammotropin hormone in pregnancy.
- Begins production during 5th week of gestation and increases progressively throughout the pregnancy
- Contributes to the development of breasts and promotes lactation
- Causes metabolic changes:
- reduced insulin sensitivity = reduction in the amount of glucose utilised so more is available for the fetus
- Promotes the release of fatty acids = acts an an alternative energy source for the mother.
When diagnosing illness, choosing the right specimen for the following conditions:
1- UTI 2- Wound 3- Meningitis 4- Pyrexia of unknown origin 5- pneumonia
1- midstream urine 2- pus or swab 3- CSF and blood 4- Blood culture and serology 5- Sputum, lavage (tube into lung, some material pushed our slightly, then syringed back through the tube for assessment), serology
Name the 4 ways by which labs usually examine samples.
- Direct examination (E.g. Smear Diagnosis: Rapid, simple, cheap, not sensitive or specific so requires expertise)(Requires microscopy: light microscopy good for direct smear like when examining stool, and gram bacteria like in CSFm fluorescent is good for RSV)
- Culture (Slow, organisms can be rendered negative by antibiotics and you miss a diagnosis, more sensitive than smear and allows susceptibility testing (so tells you what antibiotic the bacteria is sensitive to), and allows rapid presumptive diagnosis and detailed identification)
- Serology (detect changes in the body in response to an infection that has taken place already: detect high IgG concentration, rising and falling of titres so when you take two sample at different times you get to see if it is acute or chronic as the antibodies would be rising or falling)
- Molecular (DNA hybridization and NAAT)
Name two examples of serological techniques.
- Agglutination
- Precipitation
Define sensitivity.
The ability of a test to detect all of the true positives
Define specificity.
Ability of a test to identify the number of true negatives
- Name an example of a bacteria part of the normal flora.
- Explain why it is always important to take test results in the context of the normal flora.
- Staph Aureus/epidermidis/haemolyticus
- because normal flora can contaminate a sample but not actually be colonisers. so for example staph aureus is found on the skin naturally but it may pop up on a blood culture when it is not a coloniser
Outline the principles that inform safe prescribing in pregnancy and when breastfeeding
- Pre-conception counselling to all women who want to get pregnant and are prescribed drugs
- Balance benefit to the mother against the risks to the foetus
- Drugs that have been extensively used in pregnancies and appear to be usually safe should prescribed rather than new untried drug
4- Try and use the smallest effective dose
Define teratogencity/teratotoxicity.
The ability of a drug to cause fetal malformations (1st trimester)
Define fetotoxicity.
the ability of a drug to cause functional changes to the fetus (2nd and 3rd trimester)
Name classes of drugs that are teratogenic.
The A-Club:
- Anti-psychotics
- Anti coagulants
- Anti-convulsants/Anti-epileptic
- Anti-metabolites
- Acne drugs
- Alcohol
- Androgens
- Anti-biotics
Name a teratogenic cardiovascular drug in first trimester.
ACEi
Name GI drug that should be avoided in pregnancy.
PPI
Name an anti-coagulant that should be avoided in pregnancy.
Warfarin (Causes warfarin embryopathy)
A woman is severely epileptic with fits occuring frequently causes falls. Should she be on anti-epilepsy drugs or not?
- All anti-epilepsy drugs are teratogenic
- however in this situation (and others) uncontrolled epilepsy is more dangerous than taking no medication
- Use lamotrigine as it is more safe
Describe some of the risks associated with IVF for both the mother and the child.
- Ovarian Hyperstimulation syndrome (occurs due to superovulation as a response to the drugs used in IVF - more than one oocyte in the follicle)
- Transferral of several embryos (unintentionally) à multiple births
- Welfare of child - women cannot be provided with treatment unless the welfare of the child who would be born as a result of the treatment has been taken into account, but also any other child that could be affected by the birth - there needs to be supportive parenting.
What is the role of the HFEA in regulating assisted reproduction in the UK?
○ HFEA: Human Fertilisation and Embryology Authority
○ It regulates and provides information
○ Regulates treatment (inspects and licenses clinics)
○ Regulates Research (Licenses for human embryo research)
○ Human Fertilisation and Embryology Act 1990, 2008 deal with IVF
○ The 2008 act indicates the need for supportive parenting
Outline the Scottish Government’s most recent (2016) recommendations for IVF on the NHS.
○ Guidelines for IVF In Scotland
- <40 yo: 3 cycles of IVF allowed
- 40-42: 1 cycle of funded IVF (need to discuss implications of IVF and pregnancy at this stage)
True or false. A surrogate mother is not the legal mother of a child
False.
+ In the UK surrogate mother is always the legal mother from birth (parental order or adoption is required for this to change)
Name one ethical issue arising with IVF at the stage of access (to IVF) on the NHS.
- Whether homosexual couples should be allowed
- NHS Greater Glasgow and Clyde (2009) - This case origianlly denied gay couples IVF. Here th NHS GGC refused IVF for a couple based on the basis that they do not meet the criteria that couple attempting should be able to conceive biologically. Ruling: the board reviewed HFEA 2008 and Equality act (Sexual Orientation) 2007 and overturned the decision
what organisation is responsible for regulating treatment and research of IVF
human fertilisation and embryology authority
human fertilisation and embryology act 1990
Other than homosexual couple, what other ethical issues are there relating to access to IVF.
- Whether single women are allowed to use IVF on the NHS
- Case: Elizabeth Pearce - miss pearce cited articles 8 and 14 of the european convention on human rights (rights to family and private life and prohibtion of discriminatiojn) - stated it is her right to be a mother doesnt matter she is single - allowed single women to access IVF
Name an ethical dilemma regarding IVF and Gametes.
If gametes are frozen then there is question as to how long they can be frozen and what happens in the scenario of death
or
is it okay to be a donor if they are donated? (they can in the UK - £750)
True or false. Surrogacy Agreements are legally enforceable.
False
They are not unlawful but they are not enforceable
Explain recent trends in the prevalence of vaginal births versus C-sections and relate these to the increasing professional dominance of obstetrics.
- Continuous increase in c-sections in last two decades
- Associated with increased institutionalised delivery (98% take place in hospital)
- C-section resulting from a domino-effect of medical interventions, these intervention are the results of dominant obstetric knowledge which produces a cascade of medical interventions (so obstetrician decides a woman should not stay in hospital long, this is probably due to targets and time constraints at hospital -> induce labor -> synthetic oxytocin -> epidural needed now because of pain -> this causes relaxation so more Synthetic oxytocin needed -> eventually leads to contractions that are too strong -> problems could occur to baby -> need a C-Section now! and saving the child is attributed to C-Section rather than the interventions)
- In addition to this dominance, the authrotative nature of obstetric knowledge means they direct birth and prefer to carry out c-section as they are quick and carry less responsibility as they can argue they done everything they can and women trust their advice and rely on it so go for c-section
Describe what is meant by authoritative knowledge.
Not the correct knowledge, nor exactly the knowledge of ‘people in authoritative position’ but it is the knowledge that carry’s more weight and that is made to count in the particular setting in which it is used.
- usually made to count due to association structural superiority or its efficacy
The ‘authority’ of the knowledge is not forcefully given, but the authoritative status of the knowledge is ‘negotiated’ through specific interactions.
Name 4 factors that negotiate/lead to authoritative status (e.g. makes the knowledge of an obstetrician authoritative compared to patient). (Leads to vertically distributed knowledge)
1- technology : used to express power, expert status, and appreciated for their symbolic value as well as their use.
2- Medical staff as gatekeepers: only medical staff are sanctioned to interpret results
3- Staging a physician’s performance: when an obstetrician walks in all attention is on them by the team and not on the woman
4- Participation structure:the room is set up, and everyone is set up in a way where obstetrician has eye contact with everyone in the room except the woman who is laying supine feeling marginalised.
Explain the difference between vertically and horizontally-distributed authoritative knowledge.
Vertical (Technologized america):
▪ In birth knowledge system is very vertical where the knowledge of the obstetrician is given more value than the rest
▪ Factors that play part*
- More instructions given to a woman
Horizontal: (Rural Yucatan, Mexico)
▪ Knowledge of birth, and knowledge gained from technology used, is continuously jointly produced and displayed for inspection by who ever is involved. This way the decisions of birth are made jointly, and in a collaborative manner with multiple inputs.
▪ No instructions are given to the woman, and she remains in control
▪ Mid-wife is trusted and valued as an observer and her reassurance is valued and found to be helpful
▪ Mid-wife knowledge is from experience and reputation in the community (So no all mid-wifes are valued the same)
▪ First birth is given more instructions.
Where was Ultrasound invented?
Glasgow
