Physiology Flashcards
where does fertilisation occur?
in the fallopian tubes
After fertilisation a hollow ball of cells forms (?). The inner cell mass becomes the ? and the outer cells (?) allows ? and forms the foetal portions of the ?
blastocyst
foetus
trophoblast
implantation
placenta
Implantation of the blastocyst
Blastocyst adheres to ??
???? penetrate the ? carving a whole for the ?
When implantation is finished the blastocyst is completely buried in the ?
?? differentiates into the developing ?
endometrial lining
cords of trophoblastic cells
endometrium
blastocyst
endometrium
inner mass
embryo
structures that form the placenta
Finger like projections of ?? form the ?? which protrude into a pool of ??.
??? are broken down by the expanding ? so that ?? oozes through the spaces between the ??.
??? branch off umbilical arteries and project into the ??
Foetal blood is separated from maternal blood by the ?? and thin ?? that forms the placental villi.
Maternal blood enters through the ?? then enters the pool of ?? in the ??
Foetal blood exits through the ?? and the maternal blood exits through the ??
chorionic tissue
placental villi
maternal blood
maternal capillary walls
chrorion
maternal blood
placental villi
foetal placental arteries
placental villi
capillary wall
chorionic layer
maternal arterioles
maternal blood
intervillus spaces
umbilical vein
maternal venules
what are the functions of the placenta?
Kidneys
Digestive system
Respiratory system
Temporary endocrine gland during pregnancy
why is the placenta a unique endocrine gland?
it is a transient tissue and secretion of its hormones is not subject to extrinsic control.
the type and rate of hormonal secretion is dependant on the stage of pregnancy.
During pregnancy ? endocrine glands interact for the development of the ?, coordination of ? and preparing the ?? for after birth
3
foetus
birth
mammary glands
name the three placental hormones
hCG - human chorionic gonadotropin
oestrogen
progesterone
what does hCG do?
Acts to prolong the lifespan of the ??
Stimulates precursor ? cells in ? foetal ? to produce ?
hCG may trigger ??
corpus luteum CL
leydig
male
testes
testosterone
morning sickness
the corpus luteum is maintained by hCG. what does the corpus luteum do?
produces oestrogen and progesterone for 10 weeks post implantation
Persistence of oestrogen and progesterone maintains pregnancy
what do pregnancy tests detect?
hCG
hCG levels peak after ??, this is then reduced to a low level for the rest of pregnancy
60 days
oestrogen
Secreted by ?? in 1st trimester
Secreted by ? in 2nd and 3rd trimester
Synthesis from ?
corpus luteum
placenta
cholesterol
roles of oestrogen
Stimulates growth of ? -> uterine musculature needed to expel the foetus in ?
Promotes development of ??? for ? to pass through
myometrium
labour
mammary gland ducts
milk
progesterone
Secreted by ?? in 1st trimester
Secreted by ? in 2nd and 3rd trimester
Placenta converts ? into progesterone
corpus luteum
placenta
cholesterol
the amount of progesterone produced depends on what?
the size of the placenta so in the first 10 weeks the placenta can’t produce enough hence hCG.
The increase in levels of porgesterone over last 7 months reflects placental growth.
roles of progesterone
Prevent ? by suppressing ? of uterine ?
Formation of ?? in cervical canal to prevent vaginal components reaching the ?
Stimulates development of ?? in breasts for ?
miscarriage
contractions
myometrium
mucus plug
foetus
mammary glands
lactation
The gestation (pregnancy) period is ? weeks from conception (? weeks from last menstrual period)
38
40
remember
Changes that happen to the mother during gestation:
Uterine enlargement
Breast enlargement and develop ability to produce milk (oestrogen and progesterone)
Blood volume increases by 30%
Weight gain
Respiratory activity increases by 20%
Urinary output increases
Increased nutritional requirements for the mother
Changes during late gestation in preparation for parturition (giving birth)
? contractions in ? -> mild contractions
? of the ? by relaxin
Foetus shifts ? -> ?downwards
Breech birth -> anything other than the ? is at birthing canal
braxton-hicks
last trimester
softening
cervix
downwards
head
head
Parturition (labour) requires what? 2
dilation of cervical canal
contraction of uterine myometrium
labour initiation
? cause babies head to put pressure on cervix
? is released and ? which increase contractions
contractions
oxytocin
prostaglandins
what are the three stages of labour?
cervical dilation
delivery of baby
delivery of placenta
labour - cervical dilation
Membrane around ?? ruptures releasing ??
Cervix dilates to ?
Can take ? hours
amniotic sac
amniotic fluid
10cm
many
