embryology Flashcards
(133 cards)
1
Q
site of produciton fo sonic hedgehog
A
base of limbs in zole of ploarizing activity
2
Q
what is role of sonic hedgehog
A
patterning along ANTERIOR POSTERIOR AXIS
3
Q
what happens if sonic hedgehog mutation
A
CNS development anterior posterior
holoprosencephaly
4
Q
where is wnt-7 produced
A
apical ectodermal ridge at the distal end of each limb = thickened ectodermal ridge
5
Q
what does wnt-7 do?
A
necessary for proper organization along dorsal-ventral axis
6
Q
where is fgf made?
A
at apical ecotdermal ridge
7
Q
what does fgf do?
A
stimulates mitosis of underlying mesodrem
lentening of limbs
8
Q
what are homeobox genes
A
involved in segmental organization fo embryo in a craniocaudal direction
9
Q
what do hox genes code for
A
transcription factors
10
Q
what happens if hox genes are mutated
A
appendages in wrong locations
11
Q
name the gene involved in anterior posterior axis
A
sonic hedgehog
12
Q
name the gene invovled in ventral dorsal organization
A
wnt7
13
Q
name the gene involved in lengethening of limbs
A
FGF
14
Q
name the gene involved in craniocaudal direction
A
homeobox genes
15
Q
describe what is happenign on day 0 of early fetal development
A
fertilization by sperm, formign zygote and initaiting embroygensis
16
Q
what happens in the first week of early fetal development
A
hCG production begins aroudn the time of implantatino of the blastcyst
17
Q
when does the blastocyst implant
A
day 6
18
Q
what happens in the second week fo early fetal development
A
bilaminar disc - epiblast and hypoblast
two weeks, two layers
19
Q
what happens in the third week of early fetal development
A
trimaniar disc
gastrulation
primitive streak, notochord, mesoderm and its organiation and neural plate begins to form
20
Q
when is the embryonic period?
A
3rd to 8th week of gestation
21
Q
when does the neural tube form and close
A
tis formed by neuroectoderm beginning at third week and closes by week 4
22
Q
what goes on in the embryonic period
A
neural tube formes from neuroectoderm and clsoes by week 4
organogensis
EXTREMELY SUSCEPTIBLE TO TERATOGENS
23
Q
when does the heart first start to beat
A
week 4
24
Q
whne do upper and lower limb buds begin to form
A
week 4
4 weeks = 4 limbs
25
when is the heart beat first able to be heard via transvaginal ulstrasound
week 6
26
what happens in week 6
fetal cardiac activity visible by transaginal ultrasound
27
when deos the genitalia have male and female characteristics?
week 10
28
what happens in week 10
genitalia have male and female characteristics
29
define gastrulation
proces that forms the trilaminar embryonic dist
30
when does gastrulation happen
week three
31
what is the result of gastrulation
estabilshed the ectoderm, mesoderm and endoderm gem layers
32
how does gastrulatio begin
starts wtih teh epiblast invaginationg to form the primitve streak
33
what is forming at the same time in gastrulation
primitive streak
notochord
mesoderm and its organization
neural plate beigns to form
34
define: agenesis
absent organ due to absent primordial tissue
35
define: aplasia
absent organ despite presence of primordial tissue
36
hypoplasia
incomplete organ development, primordial tissue present
37
define: deformation
extrinsic disruption; occurs after embryonic period (308 weeks)
38
define: disruption
secondary breakdown of previously normal tissue or struture
39
what type of error in organ morphogenesis is amniotic band syndrome
disruption - secondary breakdown or previously normal tissue or struture
40
define: malformation
intrinsic disruption
| occurs during embryonic period 3-8th week
41
what is a sequecne
abnormalities result form a signel primary mbryologic event
42
when is the developing baby most susceptible to teratogens
in the embryonic period
organogenesis
3rd to 8th week
43
describe effect of teratogens before the embryonic period
all or none effect
44
describe effect of teratogens after week 8
growth and function affected
45
what is the leading cause of intellectual disability in the USA
fetal alcohol syndrome
46
what is the most common cause of low birth weight in developed countries
smoking
47
effects of alcohol on fetus
increased incidence of congeintal abnormalities
pre and postnalta developmental retardation
microcephaly
facial abnormalities - smooth philtrum, hypertelorism, limb disolcation, heart defects
heart lung fistulas
holoprosencephay
48
what is the mechanism behind congenital abnormalities in fetal alcohol syndrome
failed migration
49
describe facial anomalies in fetal alcohol syndrome
smooth philtrum
| hypertelorsim - organs are too far apart
50
what are the most severe abnormalities in fetal alcohol syndrome
holoprosencephaly and heart lung fistulas
51
what are the toher defects in fetal alcohol syndrome besides facial abonrmaolities
heart defects
limb dislocation
intellectural disabiltiy
microcephaly
52
```
what is the teratogen
smooth philtrum
heart lung fistula
hypertelorism
intellectula disability
microcephaly
heart defects
limb disolcation
```
alcohol!
53
most common cause of low birth weight in deeloped coutnries
smoking in rpegnancy
54
most common casue of intellectual disability in developed countries
alcohol
55
whats the difference between dizygotic twins and monozygotic twins
dizygotic twins - from two egges separtely fertilzed by two different sperm - alwasy two zygotes with two separate amnion and two separtae placenta
monozygotic - from 1 fertilized egg and 1 sperm that splits into 2 zygotes before day 13.
56
what determines the number of chorins/placenta and amnion/fetal membranes in monozygotic twins
the timing of the separtion fo the 1 fertilzied egg
57
describe type of monozygotic twins that cocurs if division occurs between teh 2 cell stage and the morula
dichorionic
diamniotic
monozygotic twins
58
describe type of monozygotic twins that occurs if division occurs between the morula and the blastocyst
monochorionic
diamniotic
monozygotic twins
one placenta and two sets of membranes
59
describe type of monozygotic twins that occurs if cleavage occurs bweetn the blastocyst and formed embryonic disc stage
```
monochorionic
monoamniotic
monozygotic twins
one placenta
one set of membranes
```
60
what happens i fcleavate happens greater than 13 days after the formed embroyonic dis c has formed
monozygotic twins
monochorionic
monoaminotic
conjoined
61
twins if celavge between days 0 and 4
dichorionic diamniotic with fused or separate palcentas
62
twins if cleavage between days 4 and 8
monochorionic diamniotic monozygotes
| morula - blastocyst
63
twins if cleavage between 8 and 12 days
monochorionic monoamniotic monozygotes
| blastocyst - formed embryonic dise
64
twins if cleavage at > 13 days
monochorionic monoamniotic conjoined monozygotic twins
65
what is the most common type of monozygotic twin
monochorionic diamniotic monozygotic twins
days 4-8
morula and blastocyst
66
what is second most common type of monozygotic twin
dichorionic diamniotic monozygotic twins fused or seprate palcenta
days 0-4
two day cell to morula
67
what is the placenta
first site of nutrient and gas exchange between mother and fetus
68
what is the fetal component of the placenta
cytotrophoblast
| syncytiotrophoblast
69
what is the cytotrophoblast
inner layer of chorionic villi near featl vessels
| makes cells
70
what is the syncyciotrophblast
outer layer of chorionic villi near maternal blood
| makes hCG
71
what is the maternal component of the placenta
decidua basalis
72
what is the decidua basalis dericed from
endometrium
73
where is maternal blodo int eh palcenta
between the decidua basalis and the syncyctiotrophoblasts
74
describe what youd see in the cross section of the umbilical cord
two umbilical arteirs - bringin blodo back from the fetus to the placenta
one umbilical vein - takign blood fromplacenta to the lier and then IVC of to teh IVC via the ductus venosus and the allantoic duct amonsgt wharton jelly
75
what causes a 2 vessel cord
congenital and chromosomal anomalies - single umbilical artery
76
what does the umbilical artery do
returns deozygenated blodo from fetal internal iliac arteries to palcenta
77
what doe the umbilical vein do
supplies oxygenated blodo from placenta to dutus
| drains into IVC via liver or via ductus venosus
78
what is the urachus
@ 3rd week - yolk sac froms the allontois - extends into the urogenital sinus
allantois becomes the urachus - a duct between fetal bladder and yolk sac
79
what is a patent urachus
total failure of the urachus to obliterate - urine fischarge form umbilicus
80
what is a urachal cyst
partial failure of urachus to obliterate - fluid filled vaivity lines with uroepithelium btween the umbilicus and bladder
81
consequences of urachal cysts
infection
| adenocarcinoma
82
what is a vesicourachal diverticulum
slight failure of urachus to obliterate causes outpouchign of bladder
83
what is a urachus
the allontosi at third week connected the yold sac to the urogenital sinus -- becomes a urachs that acts as a duct between teh fetal bladder and yolk sac
84
what is the vitelline duct
at the 7th week obliteration fo the vitelline dut/omphalo-mesenteric duct that connects the yok sac to the midgut lumen
85
what is a vitelline fistula
vitelline duct fails to close - meconium distchange fromumbilicus
86
what is a meckel diverticulm
partial closure of vitelline duct with patent portion attacted to ileum
a true diverticulum
87
melena
hematochezia
abdominal pain
partial closeure of vitelline duct with patent portion attahed to ituem
true diverticulum
meckeldiverticulum
88
what type of tissue can be present in meckel diverticlum
pancreatic/gastric
89
urine from the umbilicus = ?
patent urachus
90
meconiium from teh umbilicus = ?
vitelline fistula
91
what is the pathogeneis sof cleft lip?
failure of the fusion of the maxillary and medial nasal processes - formation fo primary palate
92
what results if maxillary adn medial nasal processes fail to fuse
no primary palate
| cleft lip
93
what is the pathogenesis of cleft palate
failure of fusion of the two lateral palatine processes
OR
failure of fusion of lateral palatine processes with the nasal septum and or medial palatine processes
= formation of the secondary palate
94
what happens if the two lateral palatine processes fail to fuse
cleft palate
95
what happens if the lateral palatine process fails to fuse with the nasal septum
cleft palate
96
what happens in teh lateral palatine process fails to fuse with the medial palatine process
cleft palate
97
describe the anatomic deltas in hypospadias
abnormal openign on the ventral side
98
what causes hypospadias
failure of the urethral folds to fuse
99
what is associated with hypospadias
inguinal hernia and cyrptorchidism
100
name the defect associated with inguinal herina and cryptochidism
hypospadias
101
which is mroe common, hypospadias or epispadias
hypospadiaes
102
describe the anatomic deltas in epispadiasis
abnormal opening of the dorsal surface of penis
103
what causes epispadiasis
faulty positioning of the genital tubercle
104
what other findings are associated with epispadias
bladder exstrophy
105
what else is associated with bladder exstrophy
epispadiasis
106
failure of the urethral folds to fuse
hypospadias
107
faulty positiong of hte genital tubercle
epispadias
108
whats the role of the gubernaculum
tis a band of fibrous tissue that ancors the testes wtihin the scrotum
109
what does the gubernaculum become in feamles
the round ligament and the ovarian ligament
round ligament is from fundus to labia majora
ovarian ligament is from fundus to ovary
110
when do you suspect urethral injury
if see blood at the urethral meatus
111
what type of damage do you suspect if person has a pelvic fracture or blunt force
posterior urethra - membranous portion
| urine into the retropubic space
112
what type of famage do you suspect in a perineal straddle injuery
anterior urethra - penile urethra at risk of damage
| cause urin to leak beneath deep fascia of buck
113
what happen sif buck fascia is torn
urine can leak into superficial perineal space
114
what is injured if you see urine in the retropubic spave
membranous portion of urethra
115
what is injured if urine is contained in bucks fascia
penile portion of the urethra
116
what is injuered if you see urine in the superfiical perineal space
bucks fascia has ruptured and penile urethra inuered
117
what are teh efects of NO on the male sexual response
No - icnrease cGMP - smooth muscle relaxation - vasodilation - proecertile
118
what are the effects of NE on the male sexual response
NE - increases intracellular calcium -- smooth muscle contraction -- vasoconstriction -- antierectile
119
what causes a) Erection b) emission and c) ejaculation in male sexual response
a) parasympathetic in the pelvic nerve
b) sympahtetic in the hypogastic nerve
c) visceral and somating in the pudendal nerve
120
how do PDE-5 inhibitors work
inhibit cGMP breakdown.
| sildenafil
121
what wont happen if pelvic nerve ruined
no erection - parasympathetmc
122
what wont happen if hypogastric nerve damaged
no emission - sympahtetic
123
what wont happen if pudendal nerve damaged
no ejactulation - visceral and somatic
124
describe the stages of the female sexual response
excitement - plateau - orgasm - resolution
125
what happens in female sexual response of excitement
excitement - uterus elevates
| vaginal lubrication
126
what happens in female sexual response of platuea
expansion of inner vagina
127
what happens in female sexual response of orgasn
uterine contractions
128
what mediates the female sexual response
autonomic nervous system
129
what accompanies the female sexual response
tachycardia and skin flushing
130
what phase of female sexual response: uterus elevates and vaginal lubs
excitement
131
what phase of female sexual response: uterine contractions
orgasm
132
what phase of female sexual response: expansion fo inner vagina
platuea
133
what is the pathway of sperm during ejaculation
SEVEN UP
| seminiferous tubules - epididymis - vas deferens - ejaculatory ducts - urethra - penis
