Week 2 Flashcards
what classes primary amenorrhoea
never had a period
not gone through puberty
what classes secondary amenorrhoea
someone who has had periods but they have stopped for at least 6 months
causes of amenorrhoea at the hypothalamic level
weight loss
stress
drugs
define amenorrhoea
abnormal absence of menstruation
causes of amenorrhoea at the pituitary level
prolactinoma
pituitary tumour
causes of amenorrhoea at the ovarian level
PCOS
Premature ovarian failure
Causes of amenorhhoea at the uterine level
congenital genitourinary absence
asherman’s syndrome
physiological causes of amenorrhoea
pregnancy
lactation
other causes of amenorrhoea
iatrogenic
thyroid dysfunction
hyperandrogenism
define hirsutism
excess hair growth in a male pattern due to increased androgens and increased skin sensitivity to androgens
most common cause of hirsutism
PCOS
classic presentation of PCOS
anovulation (amenorrhoea, oligomenorrhea, irregular cycles)
associated with symptoms of hyperandrogenism
- hirsutism, acne, alopecia
how does abnormal gonadotrophin secretion present in PCOS
Increased LH concentration
- Increased LH receptors in PCOS ovaries
- Support ovarian theca cells
Decreased FSH
- Low constant levels result in continuous stimulation of follicles without ovulation
- Decreased conversion of androgens to oestrogens in granulosa cells
Which androgens, involved in androgen biosynthesis are measured when testing for PCOS
DHEA
Androstenediol
Androstenedione
Testosterone
Dihydrotestosterone
describe androgen biosynthesis and action (PCOS)
Increased androgen production from theca cells under influence of LH
Disordered enzyme action
- Ovarian enzyme expression
- Peripheral conversion
Decreased SHBG
- Produced in liver, binds to testosterone
- Only free testosterone is biologically active
Describe insulin secretion and action (PCOS)
Increased insulin in response to glucose load
Increased insulin resistance
Causes Vs association?
- Insulin stimulated theca cells of the ovaries
- Increased ovarian androgens
Insulin reduces hepatic production of SHBG - increased free testosterone
Two main treatment methods for PCOS
Weight loss
Insulin sensitizers
How does weight loss and insulin sensitizers help to reduce symptoms of PCOS
Insulin sensitisers act on weight loss.
Both of above act to reduce insulin.
This acts on liver to increase SHBG and on the ovary to decrease androgens.
These work to reduce free testosterone which leads to increase in ovulation and a decrease in hirsutism.
Describe metformin
For obese and non-obese
Improves insulin sensitivity
Leads to decrease LH levels and increased SHBG and hence decrease in FAI.
Not useful in infertility
not very effective against hirsutism
May have a place in management of women at high risk of diabetes
Mechanism of COCP on hirsutism
ovarian androgen suppression
mechanism of corticosteroids on hirsutism
adrenal androgen suppression
mechanisms of spironolactone and cyproterone acetate on hisutism
androgen receptor antagonist
mechanism of finasteride on hirsutism
5 alpha reductase inhibition
mechanism of eflornithine on topical inhibitorhisutism
topical inhibitors
difference between community and hospital midwives
community - monitor up until labour. based in GP. routine check appointments.
hospital - responsible for mother and baby during labour
number of appointments a pregnant mother has
first pregnancy - 7
second/third etc pregnancy - 5
what happens at week 12
dating scan - ultrasound
- hospital by sonographer
- check development and placenta
potentially combined screening test
what happens at week 20
anomaly scan
- detailed ultrasound
screening for HIV, syphilis and Hep B
what happens at week 8
first appt with midwife at GP
- patient given plan of care
- height, weight and BMI measured
- bp measured and urine dipstick
- risk factors for pre-eclampsia
- offer dating and anomaly scan appts
- assess patients mental health
advanatges and disadvantages of midwife led units
more relaxing, may know the midwife, may be closer to home
if seperate to hospital, no access to certain pain relief such as epidural
may need to transfer to consultant-led unit if complications
advantages and disadvantages to consultant-led unit
direct access to obstetrician, anaesthetists and epidural.
special care unit close-by
may not know midwife
may need to stay on postnatal ward
describe chorionic villus sampling
sample is taken from the placenta using ultrasound guidance
carried out at 11-14 weeks
1 in 100 risk of miscarriage
describe amniocentesis
samples amniotic fluid containing fetal cells using a needle and ultra sound guidance
cells grown in culture then chromosomes analysed for abnormalities associated with down’s syndrome and cystic fibrosis etc.
15 weeks
1 in 100 risk of miscarriage
results in ~1 week
describe non-invasive prenatal testing
aka cell free DNA screening
cfDNA migrate into maternal blood stream via apoptotic trophoblast cells shed from placental tissue
maternal blood test at 10 weeks
not diagnostic but NO risk to pregnancy
components of combined screening
maternal age
nuchal translucency
free beta HCG
pregnancy associated plasma protein A
difference in PAPP-A in normal and downs syndrome pregnancies
in downs syndrome the distribution value is lower than normal but there is significant overlap
difference in fbhCG in normal and downs syndrome pregnancies
in downs syndrome the distribution value is higher than normal but there is significant overlap
difference in nuchal transluceny in downs syndrome
fluid filled space behind neck is larger than normal at about 3mm. this is only present in the first trimester
what is the value considered at increased risk
greater than or equal to 1 in 150
what chromosomal abnormalities are associated with down’s, edwards’ and patau’s syndromes
D - trisomy 21
E - trisomy 18
P - trisomy 13
most common cause of trisomy
nondisjunction when gametes are formed during meiosis. Instead of separating into 2 gametes, a pair of 21s will end up in one gamete. After fertilisation with another gamete, each cell will have three 21.
cause of trisomy present in 4% of cases
unbalanced translocation where the extra 21 is attached to another chromosome, commonly 14
cause of trisomy in 1% of cases
mosaics with both normal and trisomy 21 cells. In these cases, nondisjunction has occured after fertilisation during mitotic division
characteristic features of down’s syndrome
learning difficulties
slanting eyelids
small nose
large tongue
low set ears
single palmar crease
what are downs syndrome patients at higher risk of
heart conditions
infections
leukaemia
epilepsy
GI issues, constipation
hypothyroidism
eyesight and hearing
clinical features of edward’s syndrome
learning difficulties
low birth weight
decreased muscle tone
low set ears
club feet
overlapping fingers
severe side effects of edwards syndrome
congenital heart and kidney disease
breathing issues
GI defects
hernias
describe survival in patau’s syndrome
generally not compatible with life past a few weeks after birth.
many fetuses miscarry before birth and only 5-10% of children survive longer than 1 year - usually due to mosaic
clinical features of pataus syndrome
learning difficulties
microphthalmia
cleft lip and palate
extra digits
low muscle tone
undescended testes
malformed ears
chromosome pattern in klinefelter’s syndrome
male patients with an extra X chromosome
XXY
chromosome pattern in turner’s syndrome
female patients lacking an X chromosome
XO
potential clinical features of klinefelter’s
reduced IQ
infertility
underdeveloped secondary characteristics (facial and body hair)
potential breast development
potential clinical features of turner’s
neck webbing at birth
lymphedema at birth
short stature
infertility
what is erection mediated by
parasympathetic plexus at the level of S2 and S3
accompanied by increased skeletal muscle tension, increased heart rate and hyperventilation
what occurs when female’s are turned-on
vagina and clitoris engorge with blood
circumference and length of vagina increase
labia minora deepen in colour
increased secretions
uterus elevates
resp rate, heart rate and blood pressure increase
physiology of ejaculation
reflex contractions of the bulbocavernosus and ischiocavernosus
- spinal reflex under sympathetic control
contraction of structures such as ductus deferens, seminal vesicles and prostate
filling of urethra stimulates nerves in the genital region which contracts the muscles of the penis resulting in forcible expulsion of semen
physiology of female orgasm
stimulation of the clitoris and the labia result in progression towards orgasm
vaginal lubrication increases and labia become more engorged due to a marked increase in blood flow to the vagina
during orgasm, clitoris retracts and a succession of contractions occur in vaginal walls and pelvic floor
average volume of ejaculate
any volume above 1.5ml is normal. this can range up to 5ml per ejaculate
how many nerve endings are there in the clitoris
8000 (double that of the penis)
what is priapism
painful erection that occurs for several hours and occurs in the absence of sexual stimulation. When blood is trapped in the penis and unable to drain.
criteria for sexual disorder diagnosis
symptoms need to have persisted for a minimum of 6 months.
they need to have been experienced in all or almost all sexual encounters
they need to have caused clinically significant distress
mechanism of viagra
aka sildenafil
protects cGMP from degradation by cGMP-specific phosphodiesterase type 6 in the corpus cavernosum of the penis.
NO in the CC binds to guanylate cyclase receptors, resulting in increased levels of cGMP = vasodilation and increased blood flow to the penis
what is gastrulation
when the two layered disc turns into three germ layers
induction in developmenr
one cell population/tissue (inductor) acts on another tissue (responder)
stimulates a specific developmental pathway
what does the notochord turn into in vertebrates
nucleus pulposus of intervertebral disc
structure of notochord
flexible rod
ventral to neural tube
what does the notochord and mesoderm induce on the ectoderm
induces the overlying ectoderm to thicken and form the neural plate
initial event in neurulation
cells of the neural plate making up the neuroectoderm
what happens after the neural plate is induced
lengthens and lateral edges elevate
- forming neural folds and neural groove
how does the neural plate turn into the neuraltube
neural folds approach each other on the midline and fuse
this forms the tube, which then sinks in and overlying ectoderm repairs
describe bending of the neural plate
cell wedging - microtubules and microfilaments change cell shape.
hinge points - median hinge point and dorsolateral hinge points
stages of neural tube formation
day 19 - neural groove
day 20 - neural crest
day 22 - neural tube
day 25 - anterior closure
day 27 - posterior closure
describe closure of the tube
fusion begins in cervical region and proceeds in cephalic and caudal directions.
open ends form the anterior and posterior neuropores
- connect with overlying amniotic cavity
examples of induction in development
noggin and chordin
activators of inhibition - inactivate BMPs (absence of BMP4 causes patterning of neural tube and somites)
role of sonic hedgehog
critical role in development - make floorplate of neural tube patterning of brain and spinal cord,
somite patterning,
limb bud development
process of sonic hedgehog signalling
notochord presents signal to adjacent neural tube
ventral (most) cells respond to the signal and make the neural tube floorplate
floorplate now makes its own SHH
effect of SHH on sclerotome
cells to undergo an epithelio-mesenchyme transformation
they can then migrate, move towards signal and form the vertebral column
effect of SHH on dermomyotiome
induces competence to respond to signals from surface ectoderm
role of SHH in neural tube closure of upper spine
DLHPs are absent due to inhibition by BMP 2.
SHH expression is strong which inhibits noggin. WIth no noggin then theres no inhibition of BMP and so there are no DLHPs
role of SHH in neural tube bending in lower spine
SHH is reduced. Niggin is un-inhibited and it antagonises BMP2, which allows DLHPs to form.
what heppsn when there is incomplete closure of neural tube
anterior neuropore failure - anencephaly
posterior neuropore failure - spina bifida
describe spina bifida cyctica
meningocele - cyst on lower spine due to bulging of the meninges at the split in the spine.
myelomeningocele - cyst on lower spine due to bulging of meninges. However much more severe than above as it involved damage of spinal nerves as they grow into the sac.
describe spina bifida occulta
mild version of SB.
Spinal cord still well protected and so no damage to the cord. Tends to be no issues
diagnosis of neural tube defects
raised levels of alpha-feto protein
ultrasound
ways to reduce incidence of neural tube defects
folic acid taken prior to conception and in early stages of pregnancy
how many weeks is full term in the mother
40 weeks
what are the three trimetesters
1st - up to 12 weeks
2nd - 12 to 24 weeks
3rd - 24 to 40 weeks
describe the pre-embryonic period
fertilisation of ovum by sperm
multiple cell divisions leading to implantation of blastocyst into uterine endometrium around days 5-7
trophoblast cells invade the decidua to start to establish the placenta
what produces hCG
syncytiotrophoblasts (following implantation of blastocyst)
function of hCG
maintains integrity of corpus luteum (mimics LH) to promote continued progesterone and oestrogen secretion and prevent menstruation
when is the fetal period
weeks 9-birth
represents rapid growth and physiological maturation of organ systems
describe lung maturation
lungs filled with fluid
breathing movement - expulsion of fluid into amniotic sac via trachea
24 weeks - secondary pneumocytes start producing surfactant
amount is insufficient until 35 weeks
describe renal system maturation
new nephrons formed until week 36
kidneys produce dilute urine but otherwise minimal function
fetus swallows approx 7ml amniotic fluid an hour and produce approx 300ml/kg of urine per day
digestive tract maturation
not fully functional in fetus due to placenta.
maturation of enzymes for digestion and absorption.
crypts and villi develop during weeks 8-24
meconium production
describe fetal circulation maturation
hematopoiesis in fetal liver becomes dominant in second trimester
most erythrocytes contain fetal haemoglobin which has greater affinity for oxygen than adult haemoglobin
endocrine function in foetus
glands produce small amounts of hormones from 2nd trimester
- contribute to development and labour
before birth, large adrenal cortex to produce androgens
- converted to oestrogen in placenta
foetal posterior pituitary gland secretes oxytocin to initiate contractions at peak values
maternal adaptations to pregnancy
rr and tidal volume increase
blood volume increase by about 50%
nutrient requirements increase
glomerular filtration rat eincreases by about 50%
function of hPl
promotes growth and differentiation of mammary gland tissue for lactation
stimulatory function on maternal tissues - ensures glucose and protein available to foetus
function of relaxin
increases pubic symphysis flexibility and cervix dilation
suppresses release of oxytocin by hypothalamus and delyas onset of labour contractions
function of placental growth hormone
suppresses/replaces maternal GH
enhances nutrient availability to foetus by stimulating lipolysis and gluconeogenesis
hormones that breast maturation
T1 - oestrogen promotes growth and branching of the ductal system
T2 - progesterone promotes development of lobules and alveolar cells to proliferate, enlarge and become secretory
T3 - lobules continue to grow into areas of fat and connective tissue
endocrine coordination for paturition
progesterone levels reduce
oxytocin from foetal pituitary enters maternal bloodstream via placenta
oxytocin also from maternal pituitary
prostaglandin production
first stage of childbirth
dilation stage
cervical softening and dilation
frequency of contractions increase
amniochorionic membrane ruptures
longest phase - hours to days
second stage of childbirth
expulsion stage
contractions strong and frequent
mother feels urge to push
minutes to 3 hours
when is apgar score measured
1 minutes and 5 minutes post birth
third stage of childbirth
placental stage
delivery of placenta up to 1 hour post partum via contractions
can cause postpartum haemorrhage so often done via active management
- oxytocin injection and removal by midwife
