Embryology and Fetal screening Flashcards

1
Q

Explain genetic programming and expression

A

Differentiation and morphogenesis of genetics
Control of cells turning on or off
Meeting of genetic material determines many external and internal characteristics of the future child

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2
Q

Give an overview of the first 23 days

A

Formation of umbilical cord and placenta happen very early
From here there will be differentiation of cells into any of the 250-300 cells needed in the body

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3
Q

What is blastocyst

A

Cells division becomes asymmetrical
Cells polarise
Loose their totipotency and begin to differentiate
Inner cell mass - fetus
Outer cell mass - the trophoblast which develops into the placenta

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4
Q

What occurs during week 2

A

Epiblast & hypoblast= bilaminar embryonic disc
Hypoblast - endoderm layer
Epiblast - ectodermal layer
Day 14 primitive streak starts to develop- threshold at which experimentation must stop

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5
Q

What occurs during week 3 ( gastrulation cell migration and rearrangement)

A

Primitive streak in the midline
Bilaminar disc is converted into trilaminar disc
3 germ layers- ectoderm, mesoderm and endoderm
2mm long
Notochord forms induces development of the neural plate
Morphogenesis
Primitive heart - heart tube
Primitive nervous system

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6
Q

What happens during week 4 ( organogenesis)

A

Folding
C shaped embryo
Constriction between embryo and yolk sac
Beating heart present

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7
Q

What is the function of the placenta

A

Pneumonic SERPENT

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8
Q

What does the S in SERPENT and explain

A

Placenta stores glycogen, metabolises this provide glucose as fetus requires until fetal liver is sufficiently developed to function
Stores iron and fat soluble vitamins

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9
Q

What does the E in SERPENT mean and explain

A

Produces steroid ( e.g. oestrogen & progesterone) and placental ( HCG, human placental lactogen, hPGH & PAPP-A and B ) protein hormones

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10
Q

What does the R in SERPENT mean and explain

A

Oxygen and carbon dioxide transferred to and from maternal circulation to and from fetus by diffusion, transfer assisted by slight maternal respiratory alkalosis in pregnancy ( fetal uptake assisted by the higher affinity to oxygen of fetal haemoglobin and high fetal haemoglobin levels in utero )

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11
Q

What is the P in SERPENT and explain

A

Acts as a filter to most bacteria- however tubercle bacilli may transfer to fetus
Many viruses can transfer- e.g. rubella, parvo virus B19, cytomegalovirus, HIV, hepatitis
Some Protozoa can transfer- e.g. malaria, toxoplasmosis

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12
Q

What does the E in SERPENT mean and explain

A

Excretion
CO2 is main product excreted from fetus
Bilirubin also excreted due to turn over of RBC
Small amounts of urea and uric acid also excreted

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13
Q

What is N in SERPENT and explain

A

Nutrition
Fetus receives simplified raw materials for growth and development
Protein in form of amino acids
Carbohydrates in form of glucose
Fats in form of fatty acids, fats and fat soluble vitamins in later pregnancy stages
Water, and minerals

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14
Q

What is T in SERPENT and explain

A

Transfer of substances
Usual cellular membrane transport systems used
Simple diffusion of lipid soluble substances
Water pores transfer water soluble substances
Facilitated diffusion of glucose using carrier proteins
Active transport against conc gradients of ions
Endocytosis of macromolecules

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15
Q

Describe the placenta

A

Diameter- 20cm
Circumference- 62.5cm
Thickness- 2.5cm at centre, tapering towards edges

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16
Q

Describe maternal surface of placenta

A

Attached to the decidua basalia in pregnancy
Dark red in colour
Divided into 10-40 cotyledons
Cotyledons made of lobules consisting of chorionic villi
Residual remains may leave grey areas on surface of placenta

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17
Q

Describe the fetal surface of the placenta

A

Shiny, greyish blue colour, cord attached here

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18
Q

What is the outer placental membrane and explain

A

Chorion
Continuous with edge of placenta
Rough, thick, fibrous, opaque
Lines decidual Vera during pregnancy- loosely attached
Friable - ruptures easily which can reduce locally produced progesterone
Produces enzymes which can reduce locally produced progesterone
Produces prostaglandins, oxytocin and platelet activating factor which stimulate uterine activity

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19
Q

What is the inner placental membrane and explain

A

Amnion
Derived from inner cell mass
Moves over chorion aided by mucous
Can rupture and therefore cause amniotic bands
Tough, smooth and translucent, continuous with outer surface of umbilical cord
Contains amniotic fluid which it also produces to some extent as it grows
Produces PGE2 involved in initiation of labour

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20
Q

What occurs in week 5

A

Facial prominences develop
Head larger than trunk
Upper limb paddle shaped
Lower limb flipper like
Crown rump length 7-9 mm

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21
Q

What occurs during week 6

A

Upper limbs bent at elbow
Palate forming
External ear and canal formed
Crown rump length 11-14 mm

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22
Q

What happens in week 7

A

Liver prominent
Rapidly growing intestine herniate into umbilical cord
Crown rump length 16-18mm

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23
Q

What occurs during week 8

A

Fetal circulation functioning
Anal membrane perforated
External genitalia present
Ossification of bones in legs begins 8 weeks
Fingers distinct but webbed
Crown rump length 27-31mm
All organs now

24
Q

What occurs during week 9

A

The fetus is probably about an inch long and its tail has all but disappeared
Some fetuses have been shown to suck their small thumbs
The fetus has begun to make facial grimaces and even swallowing motions

25
What occurs during week 10
Baby’s brain is developing rapidly right now Well formed arms and legs as well as fingers and toes The baby will begin to kick his little feet and even open his/her mouth The baby’s intestines may begin to move into his/her body
26
What occurs during week 11
Between w 10-12 the fetus heartbeat can be heard with a hand held doppler The baby is completely developed with all the necessary major organs and systems he/she needs to survive
27
What occurs during week 12
The fetus may be up to 3 inches long and is very active Hair has begun to form on the fetus head and taste buds and vocal cords have begun to develop End of the 1st trimester
28
What occurs during week 13
Beginning of second trimester Fetus looks like a tiny infant with fully formed limbs and fingers and toes Women’s body is also beginning to swell and grow as the baby begins to take up more and more space The uterus may even pop outside of the pelvic cavity a bit
29
What occurs during week 14
Fetus neck continues to get longer and the eyes move closer together Fetus learning how to move his hands through the amniotic fluid Fingerprints are formed
30
What occurs in week 15
Fetus body is covered in lanugo which protects the skin Baby’s bones are getting harder and muscles are developing more The fetus hearing is also getting better and may jump in response to loud noises
31
What occurs during week 16
Gender of baby can be determined Baby may suck his/her thumb or grab umbilical cord The fetus is urinating and the fetus 1st stool has been forming in the intestines over the last few weeks
32
What occurs during week 17
Fetus is almost 5 inches long Body is slowly catching up to head side and fetus no longer looks so top heavy Eyes are in their final position Fetus is almost finished developing both sets of their teeth buds Begins to develop vernix and brown fat stores begin to build up
33
What occurs during week 18
Baby’s hearing becomes better each week Baby can distinguish between mom’s heartbeat and voice Fetus will even respond negatively to loud noise they don’t like Fetus eyes becoming sensitive to light and can make facial expressions
34
What occurs during week 19
Fetus brain develops at a rapid rate Millions of motor neurons are forming and nerve cells are developing to serve the senses The baby will continue to mimic the act of breathing
35
What occurs during week 20
Halfway Fetus is almost 6 inches long and 10 ounces Movements are easier A boys fetus testes will begin to drop into his scrotum Hair will begin to grow on baby’s scalp Baby’s legs are most finished growing to their final length
36
What occurs during week 21
Baby has thin eyebrows and hair continues to develop Mothers bone marrow will begin to make RBCs for fetus Movements are getting more frequent and easier to feel
37
What occurs during week 22
Taste buds are forming on the baby’s tongue Baby begin to feel world around Girl fetus has already produced all the eggs her ovaries will contain throughout life
38
What occurs during week 23
The baby will begin to develop surfactant Fat production is also still developing and the fetus begins to look more like a newborn
39
What occurs during week 24
Footprints and fingerprints are continuing to develop Every time the baby moves through amniotic fluid they create unique grooves in feet and hands The baby begins to get regular sleeping and waking cycle
40
What occurs in week 25
Baby’s eyes may still be fused shut The baby will begin to open their eyes and look around Baby has eyelashes on their eyes and eyebrows now ell formed
41
What occurs in week 26
Baby is now capable of maintaining balance and can even tell if their right side up in the uterus Baby starts to open eyes and may begin blinking Brain waves are strong Bronchial tract is developed
42
What occurs in week 27
Baby is about 2 pounds and would have 85% chance of survival if born Baby has tripled or even quadrupled in length during second trimester
43
What occurs during week 28
Baby starting running out of room The kicks and jumps will get alter as the baby begins to lose space Baby’s lanugo is beginning to disappear
44
What occurs during week 29
Baby weighs between 2 to 3 pounds Baby will kick to stretch their arms and legs Baby’s skin is less wrinkly Baby will begin to gain weight quite rapidly in preparation for birth
45
What occurs during week 30
Until baby is born they will gain up to half a pound a week The mother can feel if the baby gets the hiccups
46
What occurs during week 31
Baby weighs about 3.5 pounds and is close to 17 inches long Baby starts dreaming Boy baby testicles may still be descending from scrotum Fat stores are building up rapidly
47
What occurs during week 32
Baby will start to move to preferred position if not already Mother will feel the baby kicking in the ribs when the baby is in position
48
What occurs during week 33
The baby is 4-5 pounds The fetus head is still very pliable and skull bones are not joined at this point
49
What occurs during week 34
Fetus immune system is getting stronger The baby is still moving slowly into position and is probably head down
50
What occurs during week 35
Baby will begin to gain weight at half a pound a week Some of the bay’s features may be visible to naked eye Fat continues to build up to help maintain baby’s body temp Soft hair is now all gone Vernix is at it’s thickest
51
What occurs during week 36
The baby could weigh up to 6 pounds and about 20 inches long Baby’s immune system continues to grow and mature Baby is receiving valuable antiobodies fron the mother
52
What occurs during week 37
Mother is considered full term Baby’s lungs are almost completely matured Everything the baby needs to survive outside the womb is now finished
53
What occurs during week 38
Pasty white vernix is almost gone Baby can turn head towards light and sound Baby can blink and grimace Head remains flexible to fit through birth canal properly
54
What occurs during week 39
Baby should weigh between 5 pounds 11 ounces and 9 pounds Baby will begin to move less and less due to space restriction
55
What occurs during week 40
Baby is full term and ready to be born
56
Describe the preconception care
Diet - avid caffeine, certain foods that might harm pregnancy Exercise Supplements- folic acid Avoid risk behaviours- smoking, substance misuse, alcohol Stability in housing, home life, finances ( as much as possible) Control and stabilise existing conditions
57
When could we give pre- conception advice
When someone is considering a baby At childbearing age In contact with any medical services Sensitive conversations- private struggles with fertility, transgender men and pregnancy, previous traumatic experiences of childbirth Conversations about health promotion can and should be considered at any contact so this could be an opportunity to improve health long term