lecture 24 - development and inheritance Flashcards
(111 cards)
1
Q
intraembryonic coelem splits into:
A
splanchnopleuric mesenchyme
somatopleuric mesenchyme
2
Q
splanchnopleuric mesenchyme becomes:
A
the heart
3
Q
somatopleuric mesenchyme becomes
A
bones, ligaments, blood vessels, etc
4
Q
development of chorionic villi and placenta happens in week
A
3
5
Q
as embyronic tissue invades the uterine wall, what happens? waht does this cause
A
maternal uterine vessels are eroded
cuases trophoblastic lacunae to form intervillous spaces that fill with maternal blood
6
Q
chorionic villi develop as:
A
develop as outgrowths of the chorion that project into the endometrium
7
Q
by the end of the third week, what develops in chorionic villi? what will they connect to/
A
blood capillaries that will connect to the embryonic heart by umbilical arteries and veins via the connecting stalk
8
Q
intervillous spaces function
A
bath chorionic villi in maternal blood
bloods do not mix
9
Q
placentation
A
forming of the placenta
10
Q
what forms the placenta (2 layers)
A
chorioic villi of the chorion
- fetal portion
basal layer
- maternal portion
11
Q
functions of placenta (3)
A
allow exchange of nutrients and waste between mom and baby
produce hormones for sustaining pregnancy
acts as a barrier to most microorganisms
12
Q
example of things that can pass the placenta
A
drugs, alcohol, HIV
13
Q
umbilical cord develops from
A
the connecting stalk
14
Q
umbilical cord function
A
connect placenta to embryo
15
Q
umbilical cord makeup
A
2 arteries
- carry deoxy retal blood to placenta
1 vein (big)
- carry oxy blood to fetus
16
Q
afterbirth
A
placenta detaches from uterus following birth
17
Q
what is special about the blood in the umbilical cord
A
called cord blood
pluipotent stem cells are sourced from here
18
Q
stem cell terminology (5)
A
totipotent
pluripotent
multipotent
oligopotent
unipotent
19
Q
totipotent stem cells (def and example)
A
can form any of 220 cells types in the body. can form an entire organism
ex. blastomeres, zygotes
20
Q
pluripotent stem cells (def and example)
A
tissue specific, differentiate from totipotent cells but can form MANY cells, not ALL cells.
ex endoderm, mesoderm, ectoderm
21
Q
multipotent stem cells (def and example)
A
differentiate into a group of closely related cells
ex. hemotopoietic cells that can form myeloid and lymphoid stem cells (for blood cell/lymphocyte production)
22
Q
oligopotent stem cells (def and example)
A
develop into only a few cell types
ex myeloid cells that form different blood cell types (but not lymphocytes like multipotent cells)
23
Q
unipotent stem cells (def and example)
A
produce only one type of cell
ex. spermatogonia only form sperm
24
Q
weeks 1-8 are known as ______. what are the main 2 processes that take place in these weeks
A
embryonic period or first trimester
organogenesis and placentation
25
4 major events from week 3 and brief description of what they are
gastrulation
- primary germ layers
neurulation
- segmentation of ectoderm to separate neural tissue from skin
somite formation
- segmentation of mesoderm to separate heart from bones/blood vessels
formation of heart
26
week 4 events (1)
organogenesis
27
how big does the emrbyo grow in week 4
3 times
28
embryonic folding
process where the flat embryonic disc folds into a 3D cylinder: head/tail, and two lateral folds
looks like a contact lens sort of
29
after embryonic folding, the embryo now has a distinct: (4)
superior/inferior, left/right, anterior/posterior, and primative gut
30
organogenesis
formation of body organs and systems
31
what week do the pharyngel arches develop
4
32
pharyngeal arches and what they contain
protrusions below the "head" of the fetus
each contains an artery, cranial nerve, and skeletal muscle
33
what separates pharyngeal arches
pharyngeal grooves
34
pharyngeal arches
separate pharyngeal grooves on the ectodermal side
35
what is on the endodermal side of the pharyngeal arches
pharyngeal pouches
36
pharyngeal arches are made of;
ectoderm, mesoderm, and endoderm layers except in teh groove area
37
what do teh pharyngeal pouches form?
future head and nekc structures
38
otic placode is made of _____ and forms the___-
ectoderm, forms future internal ear
39
lens placode is made of ______ and forms the ______
ectoderm, forms future lens of eye
40
limb buds
mesoderm covered by ectoderm, create future limbs
41
heart prominenece
distinct projection on ventral surface that will become the heart
42
when do teh limb buds form
week 4
43
when does the heart prominence form
week 4
44
development in week 5-8 8 is:
rapid
45
development of in week 5-8: head
rapid brain development and growth of head
46
development of in week 5-8: heart
becomes 4 chambered, blood cells form in liver
47
development of in week 5-8: limbs
limbs form and lengthen, digits develop and separate
48
development of in week 5-8: face
eyelids and auricles form
49
development of in week 5-8: external genitals
begin to differentiate, tails shorten and disappear
50
development of in week 5-8: primative gut and other internal organs
continue development
51
development of in week 5-8: bone
formation begins
52
once the embryo has clear human features, it is known as a :
fetus
53
week 9-birth (2)
all structures developed in the embryonic period continue to grow and differentiate
very few structures form after week 8
(nipples, hair follicles, hand prints)
54
what happens to the fetus after week 9?
grows larger, movements start, limbs and digits lengthen, fingernails/toe develop
55
waht week can a fetus survive prematurely
24
56
from 28 weeks to birth, what happens to the fetus? (5)
rapid growth, strength gain, brain development, changes in respiratory and circulatory systems to prepare for breathing, head changes proportion
57
3 main causes of abnormal development
1. unknown
2. genetics
3. environmental (teratogens)
58
teratogens
one of the causes of abnormal development
eg. alcohol, viruses, smoking, radiation etc
- most harmful during weeks 3-8 (organogenesis)
59
fetal ultrasound
transducer emits high freq sound waves that reflects sound waves converted to an image on a screen
- patient needs full bladder
- used to confirm pregnancy, determine fetal age, viability, growth, gender, and abnormalities
60
quad screen
non invasive test done between 16-18 weeks
tests maternal blood for 4 things:
- alpha fetoprotein (AFP) produced by fetus
- hCG produced by placenta
- estriol produced by fetus/placenta
- inhibin A produced by placenta
61
abnormal levels in a quad screen may indicate:
neural tube defect (too much AFP)
trisomy 21, 18 or other chromosomal disorders
62
AFP
alpha fetoprotien
63
amniocentesis test is used to detect
suspected genetic abnormalities
64
how is amniocentesis done
needle through abdominal wall remove some amniotic fluid that contains fetal cells for analysis
65
what is done with the amniotic fluid is an amniocentesis
fetal cells from the fluid are examined for chromosomal abnormalities
66
chorionic villi sampling proceedure
needle through abdominal wall OR suction thru cervix to remove chorionic villi (contains same genome as fetal cells)
can be preformed as early as 8 weeks
67
chorionic villi sampling is used for
detecting genetic abnormalities
68
hCG
human chorionic gonadotropic
69
hCG is secreted by
the chorion
70
hCG function
stimulates continued production of estrogen and progesterone by corpus luteum whihc is necessary for attachment of embryo /fetus to endometirum
71
when can hCG be detected in blood
8 days after fertilization
72
when does hCG peak
week 9, then decreases in month 4-5 and levels off till birth
73
estrogenes and progesterone are produced by _____. when?
corpus luteum in the first 3-4 months of pregnancy to maintian uterus lining and prepare mammary glands, increases a lot later on
74
progesterone function
keeps uterine myometirum relaxed and cervix closed
75
hCS
human chorionic somatomammotropin
76
human chorionic somatomammotropin
(hCS) functions (2)
helps prepare mammary glands for lactation
decreases glucose use in mother so that more glucose is available for fetus
- mother will use fatty acids for ATP instead
- promotes release of fatty acids
77
corticotropin releasing hormone (CRH) functions (2)
establishes timing of birth
- high levels = premature birth
increases secretion of cortisol
- important for lung development
78
hormones secreted by placenta (4)
- human chorionic gonadotropin
- relaxin
- human chorionic somatomammotropin
- corticotropin releasing hormone
79
changes during pregnancy - GI tract
heartburn, constipation
increase appetite
80
changes during pregnancy - urinary bladder
increased frequency and urgency of urination
81
changes during pregnancy - inferior vena cava
varicose veins and edema in legs
82
changes during pregnancy - inferior vena cava, aorta, renal artery
less blood flow, renal hypertension
83
changes during pregnancy - weight gain
- increase protein, fat, water storage
- weight of fetus + all structures
- breast enlargement
- lower back pain
84
changes during pregnancy - cardiovascular
- increase heart rate (10-15%)
- increase Cardiac output (20-30%)
- maternal blood vol increases by 30-50%
all of these changes are needed to meet needs of fetus
85
changes during pregnancy - respiratory
- increase tidal volume (30-40%)
- total body O2 consumption increases by 10-20%
86
changes during pregnancy - urinary system
increased renal plasma flow, which increases GFR up to 40%
increased urination
87
labour
expulsion of fetus from uterus thru vagina
88
hormones elevated during labour (4)
estrogens, prostagandins, oxytocin, relaxin
89
what effects must be reversed in order for labour to occur? why??
progesterone secretion must stop
progesterone has been secreted by the placenta to maintain pregnancy. I relaxed the myometrium and kept the cervix closed
for labour to occur, this must be reversed
90
how are the effects of progesterone reversed for labour to start?
increased estrogen levels overcome progesterones effects
91
how to estrogen levels rise to initiate labour? (4 steps)
1. placenta secretes CRH
2. fetal anterior pituitary secretes ACTH in response to placental CRH
3. fetal suprarenal glands secrete cortisol and DHEA in response to ACTH
4. placenta converts DHEA to estrogens
loop between palcenta and fetus
92
estrogens role in labour (2)
incease oxytocin receptors on uterine muscle fibres
stimulate placenta to release prostaglandins which dilates teh cervix
93
oxytocin role in labour (1)
release by maternal posterior pituitary to stimulate contractions
94
relaxin role in labour
released by placenta, increases pubic symphysis flexibility and dilates cervix
95
positive feedback loop during labour
stimulus
- contraction of myometrium forces fetal head into cervix
receptor
- stretch receptors in cervix send impulses to hypothalamus
control centre
- hypothalamus/AP release oxytocin into blood
effector
- oxytocin causes more contractions, baby descends, producing more stretching of cervix
response
- cervix continues to dilate due to baby pushing on it
positive feedback loop ends with birth because stretching suddenly ends
96
false labour
abdominal pain at irregular intervals
does not intensify
97
true labour
regulate, painful uterine contractions that increase in frequency and intensity
back pain
dilation of cervix
vaginal discharge with blood
98
3 stages of true labour
dilation
expulsion
placental
99
dilation stage of labour (4)
6-12 hours
regular contractions
complete dilation of cervix
amniotic sac usually ruptures
100
expulsion stage of labour (2)
10 mins to several hours
baby move through and out of birth canal
101
placental stage of labour
known as afterbirth
placenta expelled 5-30 mins after delivery
101
how long does it take the mom to return from pre pregnancy state
about 6 weeks,, very variable
102
maternal postnatal period (3)
uterus undergoes involution (size reduction)
uterine discharge called lochia from former placenta site
cervix loses elasticity and becomes firm
103
postnatal adjustments to infant - prebirth
prebirth, teh fetus had:
placental O2/nutrient supply
placental waste removal
amniotic fluid pressure
fetal respiratory/cardiovascular system attached to placenta
104
respiratory changes in fetus after birth
increased CO2 levels in blood stimulate respiratory centre in medulla, triggers first breath
- forceful inhalations and exhalations
- rate begins and 45 breaths/min for first 2 weeks, slow after to 12
105
when is teh fetal respiratory system well developed
month 7
106
changes in cardiovascular system after birth (6)
all changes are stimulated by breathing
foramen ovale becomes fossa ovalis
- deoxy blood is now sent to the lungs
ductus arteriorsus shuts (connected aorta and pulmonary vein
- becomes ligamentum arteriosum
umbilcal vein closes
- becomes ligamentum teres
umbilical arteries close
- become medial umbilical ligaments
ductus venosus collapses
- now allows venous blood into hepatic portal vein to liver
high pulse as birth (120-180)
- o2 demand increases, increasing erythropoiesis (negative feedback loop)
107
ductus arteriosus becomes
ligamentum arteriosum
108
umbilical arteries and vein become
arteries
- medial umbilical ligaments
vein
- ligamentum teres
109
ductus venosus becomes
collapsed to allow fetal venous blood into hepatic portal vein
110
patent foramen ovale (PFO)
foramen flap remains open
occurs in 25% of births
no symptoms, not treated
unverified links to migraine and stroke occurrence
