Embryo col1 Flashcards
(148 cards)
1
Q
Germ cells
A
-gonocytes (1st primordial germ cells)
-become visible on 24th day after fertilization in endoderm of yolk sac
-large
-migrate through gut endoderm and at level of Th10 gonads develop
2
Q
Primordial germ cell for females is called
A
Oogonia
-they undergo oogenesis
3
Q
differences between oogenesis and spermatogenesis
A
mitotic pattern differs:
-oogonia increases from 2 million from 2nd embryonic month to 7 million in 5th embryonic month
-> oogonia then decreases to 1-2 million at the moment of birth
-> mitosis stops after birth of girl
-spermatogonia mitosis starts during embryogenesis but continues throughout life, diminishes around 65-70 years of age
4
Q
Teratomas
A
-in case of migration disorder, gonocytes stop on their way and migrate into mediastinum or oral region -> produce teratomas
-teratomas can show teeth, skin, hairs…
5
Q
spermihistogenesis
A
is the last stage of stermatogenesis
6
Q
Embryogenesis
A
process by which fertilized egg develops into an embryo
7
Q
ontogenesis
A
entire life cycle of an organism from fertilization to maturity
stages are:
1.prenatal development
1.1. zygote stage: fertilization and cell division
1.2.blastula stage: formation of hollow ball of cells
1.3. gastrulation: differentiation into 3 germ layers (ectoderm, mesoderm, endoderm)
1.4.organogenesis: development of organs and systems
2.postnatal develop,emt
2.1 neonatal stage: adaption outside woumb
2.2 childhood + adolescence
2.3 adulthood + aging
8
Q
morphogenesis
A
biological processes that control the shape and structure of tissues, organs, organisms
9
Q
teratogens
A
substances that cause congenital abnormalities
10
Q
organogenesis
A
formation of organs during embryonic development
11
Q
neurulation
A
formation of neural tube
12
Q
classification of etiological factors
A
genetic (chromosomal abnormalities)
structural abnormalities (deletion, duplications)
single gene mutations (marfan syndrome)
etc.
environmental factors (chemicals, physical teratogens, alcohol
13
Q
multifactorial inheritance
A
ie. spina bifida (folic acid deficiency)
cleft lip and palate
14
Q
Timing of teratogen exposure ( 3 periods)
A
- preimplantation period (0-2 weeks post fertilization)
- embyronic period (3-8 weeks post fertilization
- fetal period 9 weeks to birth
15
Q
what maturates spermatozoa
A
testosterone
16
Q
What is decidua?
A
The functional layer of endometrium
17
Q
length of spermatogenesis in days
A
64-72 days
18
Q
antigenes on spermatozoa are located in?
A
in the head of spermatozoa
19
Q
oligospermia
A
-low sperm count
20
Q
what does bilaminar embyro consist of?
A
2 cell layers: hypoblast and epiblast
21
Q
oocyte
A
-largest cell in the female body
-is surrounded by zona pellucida (20-50 micrometers)
-has cortical granuli (bigger granules that releases content during fertilization to protect againts polyspermia)
-also has lecitine (protein)
22
Q
What type of cells are in hypoblast?
A
cuboidal cells
23
Q
preconditions of fertilization
A
- enough number of reproductive cells (in 1 ml of sperm, 100-400 million spermatozoa
- alive reproductive cells (sperm lives up to a week)
- motility of spermatozoa
- presence of mucus (20-200ml)
24
Q
stages of fertilization
A
1.capacitation: head of spermatozoa releases antigenes
2.penetration of corona radiata
3.penetration of zona pellucida
4.cytoplasma fusion between sperm head and ovum
5.cortical reaction (blocks polyspermy)
6.development of division spindle and zygote
24
borderline of infertility (spermatozoa number)
less than 30 million spermatozoa
25
superfetatio
fertilization during pregnancy (in animals not humans)
26
superfecundatio
-two or more oocytes are fertilized by differen men at the same time
27
cleavage
-asynchronic mitotic division
-new cells are blastomeres
28
outer layer of blastocysts is called
cytotrophoblast
29
implantation takes place in?
-anterior or posterio wall of uterus (day 5-13.5)
30
3 stages of implantation
1. attachment of blastocyst to wall of uterus
2. development of niche into functional layer of uterus
3. implantation occurs at 13.5 days
31
What type of cells are in epiblast?
columnar cells
32
Decidua is...?
the functional layer of endometrium lining
33
decidua has 3 types?
1. decidua capsularis: endometrial tissue between conceptus and uteral cavity
2. decidua basalis: endometrial tissue between conceptus and basal part
3. decidua parietalis: all other layers of functional endometrium
34
what is placenta praevia?
implantation close to the cervix uteri
35
intrauterine stages
1. blastogenesis: development of blastocyst (fertilization day to day 16)
2. embryogenesis with development of trilaminar embryo from day 16 to day 60 (or 90)
3. fetogenesis from day 61/91 to birth
36
normal amount of amniotic fluid
800-1000ml
37
what is trilaminar embryo made of?
three germ layers: ectoderm, mesoderm, endoderm
38
How is notochordal process formed?
-by migrating cells from primitive knot between ectoderm and mesoderm
-it ends at prechordal plate where ectoderm and endoderm are fused and form oropharyngeal membrane
39
mesoderm cells form?
intermediate mesoderm forms kidney tissue (nephrotome)
head mesectoder makes tissue for bones and head muscles
40
somites are used to determine
the age of embryo
somites are identified by hox genes
41
intermediate mesoderm differentiates into?
nephrotomes and forms nephrogenic blastema
42
primitive gut is divided into 3 parts
foregut
midgut
hindgut
43
inductions is caused by
chemical substances produced by distinct cell groups
group 1: paracrine factors
group 2: unites extracellular matrix proteins
group 3: cell surface proteins capable of juxtacrine induction
44
GI tract develops from
endoderm
45
embryo folding starts in week?
4
46
3 phases of intrauterine development
1. Blastogenesis: from fertilization to day 16, bilaminar embryo develops
2. Embryogenesis: from day 16 until 60, development of primordia in main orgabs, fetal membranes and placentation
3. Foetogenesis: from antenatal day 61 to birth, differentiation and maturation of organs
47
fetal membranes (2)
chorion with decidua
amnion (encloses amniotic cavity)
48
3 types of chorionic villi
1. primary villi consists of epithelium
2. secondary villi contain extraembryonic mesoderm
3. tertiary villi forms when mesenchymal cells differentiate into the bloood
49
Maturation of placenta includes:
-development of fibrinoid
- expansion of placenta surface
- hofbauer cell development
- decrease in extraembryonic mesoderm
50
spermatogenesis 4 periods
1.division (starts in early embryogenesis, leads to 2 spermatogonia type A & B)
2.growth (primary spermatocyte is formed, 46XY)
3.maturation:
-meiotic division with prolonged prophase, 5 stages in primary spermatocyte
-mitotic division "equational division" with haploid division cells, sister chromatids divide
4.differentiation (spermiohistogenesis) connectef by cytoplasmic bridges
-golgi stage: condensation
-head development: reduction of size and nucleus forms
-acrosomal stage: covers 2/3 of nucleus, digestion enzyme filled, mitochondria are organized
-maturation stage: cytoplasm forms residual bodies phagocytosed by sertoli cells
51
oogenesis (3 steps)
1. division (embryogenesis, ends at moment of birth)
2. growth starts at fetal period, oogonia meiotic division -> diplotene stage of meiosis I during first months of life
3. maturation starts with puberty when 10-30 primary oocytes complete meiotic division with each menstrual cycle
52
bones and muscles develop from
mesoderm
-mesenchymal cell condensate and form future bone model
53
vertebral column is made from
somites
-development in 3 stages: mesenchymal, cartilaginous, bone
54
ribs and sternum arise from
mesenchymal cells
head and neck part from ventromedial sclerotome
55
skull develops from
head mesectoderm,prechordal mesoderm, cranial somites and mesoderm
57
When is the sensitive period in pregnancy?
During tetragenic development phase when terarogen becomes effective
58
When is sensitive stage in CNS development?
During all intrauterine development
59
When is critical stage for CNS development?
Embryonic weeks 3-5
60
When can structural damage of the heart develop?
It can develop under influence of teratogens between week 3-5,5
But funtional heart malformations can persist until end of week 8
61
Critical stage for limb development and external genitalia?
Between weeks 4-7
For external genitalia between week 7-12
62
5 types of stem cells
1. Conceptus
2. Embryonic
3. Foetal
4. Umbilical cord
5. Adult and induced
63
Progenitors of mesenchymal stem cells develop into:
Smooth m.cells
Endothelial cells
Epithelial cells
64
Theca interna contains epithelium-like cells that produce?
Estrogens
Theca externa is rich in CT fibers and blood vessels
65
Duration of spermatogenesis
64-72 days
66
Function of LH hormone and FSH in men?
LH: stimulates leydig cells to make testosterone
FSH: acts on sertoli cells
67
Primary oocyte is the most sensitive to FSH and develops what around it?
Corona radiata and granular folliculocytes
68
Liquor folliculi is produced when?
In granular cells during secondary follicle but is more pronounced in tertiary follicle where antrum is developed
69
Secondary follicle is made of
Thick zona pellucica that separates oocyte from surrounding cells
70
Liquor folliculi contains?
Plasma proteins and FSH, LH and steroids
71
When is bilaminar embryo formed?
7.5 days or during 2nd week when embryoblast forms a later of hypoblast (cuboidal cells) and epiblast (columbar cells)
72
Amniotic cavity appears as a small space on day?
8
73
When does extraembryonic mesoderm develop?
13.5 days
-by delaminatiob of cytotrophoblast
74
75
When does extraembryonic coelom develop?
Middle of week 2
76
When does gastrulation (germ layer formation) begin (day)?
Day 15 or 16 of embryogenesis
77
Mesoderm gives material for?
- construction of body walls and extremeties
-mesoderms also make somites on day 17 and somatopleura and splanchnopleura
78
Intermediate mesoderm forms?
Basis for kidney tissue (nephrotome)
79
42-45 pairs of somites are produced by end of which week?
Week 5
Somites: 4 occipital, 8 cervical, 12 thorocal, 5 lumbar, 5 sacral, 8-10 coccygeal
80
Head mesectoderm produces tissue for?
Bones and muscles of the head
81
Activation of Pit-2 gene is responsible for?
Asymmetrical development of gut, stomach, spleen, lobation of lungs
82
83
The identity of somites is controlled by which gene?
Hox genes but FGF-8 keeps mesodermal cells labile
84
Ephrins regulate subdivision formation of what?
Somites into sclerotome, myotome, dermatome
85
Notochord secretes?
SHH which stimulates Pax-1 Pax-9 and organization of sclerotome
86
Neural tube secretes?
Wnt-1 that influences development of dermatomyotome
87
What blocks migration of somatic cells?
BMP-4
88
Cells from somites provide the most parts of?
Axial skeleton, musculature, adjacent dermis of skin
89
What is neurulation?
Development of neuroectoderm on day 18
90
Open ends of neural tube are called?
Neuroporus anterior and they close around day 24
91
hedgehog genes develop?
GI organs and symmetry of the body
92
ephrins are needed for?
blood vessel typing
93
main growth stimulating factors during embryogenesis?
insulin, EGF, TGFa, PTHRP
94
GI tract develops from?
endoderm
95
CT and muscled for GI tract develop from?
mesoderm
96
ectoderm forms?
epidermis, hair, nails, skin glands, inner ear, oral epithelium, nasal, anal canal
97
neuroectoderm forms?
neural tube and neural crest ((autonomic and sensory ganglia, scwann cells and pigment cells)
98
endoderm forms?
GI epithelium, pharynx, tonsils, parathyroid gland, thyroid gland, thymus, larynx, lungs, liver, gall bladder, panchreas, urinary bladder
99
paraaxial mesoderm forms
skeleton and trunk muscles, dermis and subcutenous tissues
100
splanchnopleura forms into
into smooth muscles, heart, haemopoietic cell precursors, mesothelium, blood vessels, CT
101
somatopleura forms into
into pleural mesothelium, pericardium, CT
102
embryofolding begins on week
4
103
pericardial cavity, pleural cavity form during month?
2
104
thoracic cavity and abdominal cavity are separated on week
end of week 4
105
placentation starts on day
13
106
HCG starts to show?
days 8-9
increased by week 8
107
which hormone regulates maternal blood glucose from week 15?
human placental growth hormone
108
when does maternal blood become more oxygenated?
after week 12
109
umbilical cord develops from?
connecting stalk
110
whartons jelly is made from
extraembryonic mesenchyme of connecting stalk and yolk sac
111
bones and muscles develop from?
mesoderm
bones: condensation of mesenchymal cells, all flat facial bones during 1st month, long skeletal bones in 2nd month
112
skeleton formation is controlled by which genes
Hox genes
sox-9 is needed for precartilage and BMP´s are needed for embryonic bone development
113
when does ossification of vertebra end?
age 14-16
114
ribs and sternum are made from?
condenced mesenchyma cells
ossification ends 20 postnatal year
115
skull is made from
head mesoectoderm, prechordal mesoderm, 4 cranial somites, and mesoderm
116
which factor is responsible for limb development?
FGF-10
Hoxb-8gene and retinoid acid
117
lower limbs appear on day?
28
118
when are all limb regions well developed?
day 56
119
skeletal elements along the axis develop on week?
5
120
Limb skeleton ossification starts between weeks?
6-7
at the end of month 3, all diaphyses are ossified
121
joint formation is stimulated by factor?
Wnt-14 which stimulates growth factor Ggf-5
122
limb musculature develops on week?
week 5 from condensation of somitic mesoderm
-muscle mass develops deom dermamiotome cells with the help of hepatic growth factor HGF
-dermamiotome cells express N-cadhering and Pax 3 genes
123
Myoblast stage for muscle development happens during month?
4
-when nuclei of cells take center place into the fiber and mature skeletal muscle fiber stage
124
regeneration of skeleltal striated muscle is done by cells?
Myosatellite cells
125
skeletal, smoot and cardiac muscle is made from?
mesoderm
126
skeletal muscles are made specifically from which mesoderm?
para axial mesoderm that forms the somites
127
myogenesis is stimulated by 2 factors?
FGF and TGF beta
-further growth is stimulated by insulin growth factor
128
muscles of the trunk develop from
myotomes
-epimer for epaxial muscles and extensors of vertebral column
-hypomer develops hypaxial and flexor muscles of the trunk
129
head muscles are made from
cranial somites, prechordal mesoderm
130
smooth musculature is made from
lateral mesoderm
-mesenchymal cells of splanchnopleura forms smooth musculature of intestinum
-local mesoderm forms into musculature of blood vessels
-heart musculature is made from splanchnopleura
131
cardiac muscle is made from
splanic mesoderm that envelops the endothelial heart tube
132
diaphram is made from 4 sources?
1. septum transversum
2. mesentery of oesophagus
3. pleuraperitoneal membranes
4. somatopleura
133
what forms epidermis, dermis and subcutise
epidermis is made from ectoderm
dermis and subcutis from mesoderm
-epidermis is differentiated during 4th month (5 layers)
134
peridermal cells are responsible for?
exchange of water, sodium, glucose between amniotic fluid and epidermis
-during 6th month the epidermis becomes the barrier between mother and fetus
135
factors that stimulate epidermis proliferation
epidermal growth factor
transforming growth factor
insulin
insulin growth factor I
FGF-2
Interleukin-1
136
factors that inhibit epidermis development?
TGF beta 1
TG beta 2
interferon alpha
tumor necrosis factor
137
germina layer forsm ridges on fingers and soles of feet during week?
6.5 on palms
7.5 on feet
138
skin pattern development continues until month?
end of 5th month
139
skin becomes similar to adult skin at age?
7
140
hair on skin develop from and is stimulated by which factor?
- made from epidermal proliferations into the dermis and is stimulated by FGF-5
141
production of sweat glands start from week?
2 until week 18
142
3 periods of blood developmen
1. day 13-14-15 megaloblastic period
2. intraembryonic hematopoeisis starts week 7
3. after 6th month medullary period
-regulated by Hox genes
143
lifespan of embryonic erythrocytes
50-70 days
144
blood vessels are formed on week?
3 by andioblasts
145
first heart pulsastions are detected on day
22
146
venous system during week 5 consists of?
vitelline veins, umbilical veins, precardinal veins
147
lymphatic system appars on week?
5
148
urinary system develops
before any gonadal development appears but URINE PRODUCTION starts on week 11
-pronephros develops from nephrotomes, initiated by paraaxial mesoderm
- on day 24, mesonephric ducts appear and are functional between weeks 6-10
-metanephros develops on week 5
