Embryo I Flashcards
definitions (147 cards)
1
Q
process in the male by which sperm are formed
A
spermatogenesis
2
Q
comprise walls of seminiferous tubules»_space; maintain environment for spermatogenic cells
A
Sertoli or sustenacular
3
Q
provides an endless supply of stem cells called spermatogonia, some of which differentiate into primary spermatocytes
A
mitosis
4
Q
produces haploid cells
A
meiosis
5
Q
temperature dependent pathway in which spermatids are streamlined to produce sperm or spermatozoa
A
spermiogenesis
6
Q
formation of eggs
A
oogenesis
7
Q
oocyte encapsulated by a flattened single layer of stromal cells
A
primordial follicle
8
Q
fluid filled cavity in follicle
A
antrum
9
Q
release of the oocyte from the ovary
A
ovulation
10
Q
“morning after” pills contain high doses of estrogens»_space; disrupts estrogen/progesterone balance thereby inhibiting ovulation
A
emergency contraception
11
Q
follicular cells remaining in ovary that secretes progesterone which is essential in maintaining enhanced uterine lining
A
corpus luteum
12
Q
follicular cells surrounding the oocyte
A
corona radiata
13
Q
glycoprotein covering that directly surrounds the oocyte
A
zona pellucida
14
Q
one haploid nucleus receives no cytoplasm
A
polar body
15
Q
mixture of sperm and glandular secretion
A
semen
16
Q
shorten life span of sperm and greatly decrease motility in female tract
A
intrauterine devices
17
Q
removal of glycoprotein coat and seminal proteins from the acrosomal plasma membrane of the sperm
A
capacitation
18
Q
activation and release of enzymes necessary to penetrate through the zona pellucida
A
acrosomal reaction
19
Q
the process by which male and female gametes fuse to form a diploid zygote
A
phases of fertilization
20
Q
primary enzyme responsible for penetration through corona radiata
A
hyaluronidase
21
Q
primary enzyme responsible for penetration through zona pellucida
A
acrosin
22
Q
after penetration of 1st sperm»_space; zona becomes impermeable to penetration by other sperm
A
zona reaction
23
Q
when 2 sperm penetrate the zona pellucida simultaneously»_space; triploid fetuses spontaneously abort
A
dispermy
24
Q
fertilization through implantation
A
pre-embryonic stage
25
implantation through 8 wk
embryonic stage
26
9 wk through birth
fetal stage
27
repeated rounds of cell division
cleavage of the zygote
28
solid mass of 16-32 blastomeres >> typical stage that enters uterus
morula
29
fluid filled hollow with inner cell mass (embryoblast) in embryonic pole
blastocyst
30
outer layer of cells
trophoblast
31
attachment and subsequent burrowing of the blastocyst into the uterine lining
implantation
32
connective tissue cells of endometrium that become engorged with carbohydrates and lipids at implantation site >> engulfed by syncytiotrophoblast
decidual cells
33
when an embryo implants somewhere other than the uterine lining >> first sign typically abdominal pain during early pregnancy
ectopic pregnancy
34
due to scarring of uterine tubes
tubal pregnancy
35
(prevents cell division) upon ultrasound confirmation of tubal pregnancy
methotrexate
36
the process by which the bilaminar disk develops into a trilaminar disk >> demonstrates three germ lines
gastrulation
37
thickening of epiblast due to proliferation and migration of cells
primitive streak
38
actively forms mesoderm until early fourth week >> then diminished to insignificant structure in embryo
fate of a primitive streak
39
when remnants of the primitive streak persist and proliferate
sacrococcygeal teratoma
40
cellular rod that develops from the notochordal process
notochord
41
thickening of ectoderm overlying the notochordal process, often called neuroectoderm >> first evident at approximately day 18
neural plate
42
formed by infolding and fusing of neural folds >> will form CNS
neural tube
43
last component of neural folds to close >> improper closing results in neural tube birth defects
caudal and cranial neuropores
44
forms many PNS structures (ganglia and sheaths of nerves) plus part of meninges and adrenal medulla
neural crest
45
enlargements of mesoderm located immediately lateral to the notochord
somites
46
will develop into body cavity
intraembryonic coelom
47
becomes body wall
somatopleure
48
becomes wall (but not lining) primitive gut
splanchnopleure
49
the development of new blood vessels >> begins in extraembryonic mesoderm and (wall of yolk sac) and then in lateral mesoderm of embryo
vasculogenesis
50
formation of new blood cells >> function of endothelial cells lining vessels of the extraembryonic mesoderm >> does not occur in embryo until week five
hematogenesis
51
consist of syncytiotrophoblasts with a cytotrophoblast core >> develop by the end of week 2
primary chorionic villi
52
have a mesenchymal core >> develop during the third week
secondary chorionic villi
53
contain capillaries in the core due to the differentiation of mesenchymal cells >> capillaries connected to embryonic circulation
tertiary chorionic villi
54
disorganized proliferating chorion (placenta) resulting from an abnomal pregnancy (
hydatidiform mole
55
triploid >> 23 maternal chromosomes and 46 paternal
results from either dispermy or endoreduplication of paternal chromosomes
fetus present but not viable
very low malignancy potential
partial hydatidiform mole
56
46 chromosomes >> all of paternal origin
results from an empty egg being fertilized by either two
sperm (dispermy) or a single sperm that undergoes endoreduplication
no fetus present
potential invasiveness and even metastatic malignancy
complete hydatidiform mole
57
lateral body wall folding toward median plane
lateral folds
58
gives rise to vertebrae and ribs
sclerotome
59
give rise to dermis of the skin on dorsum of body
dermatome
60
gives rise to gonads, kidney, adrenal cortex and ureter
intermediate mesoderm
61
dermis of skin on ventral surface
serosa of ventral body cavity
migrate into limb buds >> bones, ligaments and dermis
somatic mesoderm
62
smooth muscle of primitive gut + derivatives
serosa of viscera
heart, blood and lymphatic vessels
bone marrow and lymphoid tissues
splanchnic mesoderm
63
40 weeks LNMP or 38 weeks after conception
normal gestational period
64
irregular menstrual cycles
oligomenorrhea
65
major growth promoting factor during development >> both mitogenic and anabolic
insulin-like growth factor I (IGF-1)
66
when an infant is at or below the tenth percentile for its expected birth weight at a given gestational age
intrauterine growth retardation (IUGR)
67
chorion, yolk sac, amnion and allantois >> formed from embryo but do not become significant parts of fetus
fetal membranes
68
primary site of exchange between mother and fetus
placenta
69
functional layer of the gravid uterine lining that is shed after parturition
decidua
70
component deep to embryo >> will attach firmly to the chorionic villi to give rise to maternal portion of the placenta
decidua basalis
71
superficial portion of decidua that covers the aembryonic pole >> becomes stretched and then degenerates when compressed between the chorion and the decidua parietalis
decidua capsularis
72
all other parts of the decidua >> will come in contact with the growing chorion to obliterate the lumen of the uterus
decidua parietalis
73
villi under decidua capsularis degenerate
smooth chorion
74
villi adjacent to decidua basalis continue to grow and branch >> becomes fetal portion of the placenta
bushy or villous chorion
75
fragments of syncytiotrophoblast that enter maternal circulation >> degenerate without any problems
currently in development = maternal blood used for testing fetal DNA
syncytial knots
76
villi penetrate into myometrium (muscle layer of uterus)
placenta accreta
77
full thickness of myometrium
placenta percreta
78
placenta covers internal uterine os >> bleeding during 3rd trimester and Cesarean section required
placenta previa
79
contains allantois and umbilical vessels
connecting stalk
80
approximately 2 cm in diameter and 50-60 cm long
umbilical cord at birth
81
due to umbilical vessels being longer the cord itself
false knots
82
inserts at edge of placenta
battledore placenta
83
inserts into fetal membranes with vessels then transversing between amnion and chorion >> easily torn
velamentous insertion
84
result from tears in the amnion >> origin most likely infection or toxic insult
can encircle head or extremities >> amputations, ring constrictions or craniofacial abnormalities
amniotic bands
85
primarily composed of maternal interstitial fluid
minor amounts produced by amniotic cells
amniotic fluid
86
fetal excrement in the amniotic fluid >> occurs during very late pregnancy
meconium
87
too little amniotic fluid
oligohydramnios
88
nutritional source during weeks 3 and 4
first site of hemopoiesis
incorporated as midgut during week 4 >> endoderm gives rise the epithelium of respiratory and digestive organs
site of development of primordial germ cells
yolk sac
89
its blood vessels give rise to the umbilical vessels
allows for better exchange through placental membrane
portion becomes the urachus >> becomes the median umbilical ligament
allantois
90
rostral u-shaped portion
pericardial coelom
91
superior lateral portions
pericardioperitoneal canals
92
inferior lateral portions
peritoneal coelom
93
double layer of peritoneum that originates as an extension of
the visceral peritoneum to cover an organ
mesenteries
94
located in lateral walls of pericardioperitoneal canals
pleuropericardial membranes
95
contribute muscle to the periphery of the diaphragm
lateral body walls
96
typically occurs posterolaterally allowing abdominal contents to enter thoracic cavity
results in pulmonary hypoplasia that can be life threatening
congenital diaphragmatic hernia
97
congenital anomalies = congenital malformations = developmental disorders present at birth
birth defects
98
agents that cause birth defects
teratogens
99
causes IUGR
cigarette smoke
100
constricts uterine blood vessels
nicotine
101
maternal consumption believed to be most common cause of mental deficiency >> more pronounced effects if poor nutrition also a factor
alcohol
102
children have behavioral and learning difficulties >> caused by moderate consumption or 1-2 binges
fetal alcohol effects
103
growth, physical and mental anomalies associated with children who mother was a chronic alcoholic during pregnancy
fetal alcohol syndrome
104
cause masculinization of female fetuses
androgens
105
component of birth control pills >> VACTERL syndrome (vertebral, anal, cardiac, tracheal, esophageal, renal and limb anomalies)
progesterone
106
genital tract anomalies in both sexes and increased incidence of adenocarcinoma of the vagina later within the child
diethylstilbesreol (a synthetic estrogen)
107
yellowing of teeth, low enamel deposition and diminished growth of long bones
tetracycline
108
handful of cases reporting 8th cranial nerve damage
streptomycin
109
classic example of a teratogenic drug
commonly utilized as to treat morning sickness 1957-61
causes meromelia
other medical uses but only for women on non-childbearing age
thalidomide
110
causes mental retardation and motor dysfunctions
most commonly obtained through fish and seafood
mercury
111
causes increased miscarriage, multiple anomalies, IUGR and functional deficits
maternal exposure to sub-clinical levels can cause neurobehavioral and psychomotor disturbances
most common source is dust or chips from paints used prior to 1978 >> many other potential sources as well
lead
112
produce IUGR and skin discoloration
coolant/insulator used until 1979 >> persists in environment and accumulates in sports fish
polychlorinated biphenyls (PCBs)
113
interferes with eye and/or ear development
rubella (German measles)
114
usually asymptomatic in mothers, but can be lethal in infants or produce mental retardation
cytomegalovirus
115
asymptomatic in mother, but affects CNS in infants
obtained from raw meats and the feces of domesticated animals, particularly cats
Toxoplasma gondii
116
high does rapidly kills proliferating cells >> also a mutagen
radiation as a cause of birth defects
117
poorly controlled diabetic mother 3-4X greater risk of birth defects, plus higher incidence of stillbirths, neonatal deaths and macrosomia
diabetes
118
high serum phenylalanine teratogenic for mental retardation, microcephaly and heart defects
phenylketouria (PKU)
119
animal studies link several vitamin and mineral deficiencies to birth defects, but only two widely accepted for humans
nutritional deficiencies
120
leads to congenital cretinism >> results in retarded growth and brain development
iodine deficiency
121
leads to neural tube disorders
folate deficiency
122
narrowing of lumen
stenosis
123
lack of lumen
atresia
124
celiac trunk is blood supply to ___?
foregut (distal to pharynx)
125
superior mesenteric artery is blood supply to ___?
midgut
126
inferior mesenteric artery is blood supply to ___?
hindgut
127
rapid growth to yield most of small intestine
cranial limb
128
intestines remain herniated into umbilical cord at birth
omphalocele
129
umbilicus does not properly close >> abdominal contents herniate upon increased abdominal pressure
umbilical hernia
130
incomplete closure of lateral folds resulting in protrusion of viscera
gastroshisis
131
results in small intestine on right and entire colon on left >> fairly common
nonrotation
132
results in appendix located near liver
subhepatic cecum
133
small intestine wrapped in a hernia-like mesentery sac
internal hernia
134
twisting of intestines >> creates obstruction
volvulus
135
causes anomalies when is fails to degenerate
omphaloenteric duct
136
proximal omphaloenteric duct fails to degenerate, leaving a blind-ends pouch >> can become inflamed and mimic appendicitis
Meckel’s diverticulum (ileal diverticulum)
137
produces umbilicus that is open to ileum >> allows release of digestive material
omphaloenteric fistula
138
can become infected >> painful with possible drainage through umbilicus
omphaloenteric cysts
139
can allow blood bleeding through umbilicus
persistent fibrous cord with vitelline artery
140
urethra, vagina and rectum empty into a single vestibule
persistent cloaca
141
anal canal ends blindly, or forms fistula with vagina or urethra
anal agenesis, with or without fistula
142
anus exists anterior to anal pit
anoperitoneal fistula
143
nonfunctional lungs histologically resemble an exocrine gland
pseudoglandular period (6-16 weeks)
144
development of respiratory bronchioles and distal structures + increased vascularization
canalicular period (16-26 weeks)
145
number of alveolar sacs increases + thinning of respiratory membrane
terminal sac period (26 weeks to birth)
146
increased number + thinning of alveoli >> 95% of mature alveoli develop postnatal
alveolar period (birth to 8 years)
147
premature infants lack surfactant and cannot ventilate properly
infant respiratory distress syndrome
