T2 review Flashcards
(176 cards)
1
Q
Where does the mesoderm originate and how does it move?
A
from the epiblast, moves through the primitive streak as bottle cells
2
Q
What is the pathways of mesoderm development?
A
originates from epiblast, passes through primitive streak as bottle cells, spreads laterally and establishes a continuous layer between ectoderm and endoderm.
3
Q
What are the divisions of the mesoderm?
A
paraxial (segmented somite), intermediate (urogenital), lateral plate (lines limbs and most internal organs).
4
Q
What forms first, somites or somitomeres?
A
Somitomeres
5
Q
When do somites form?
A
after 20 pairs of somitomeres are formed, somites then form caudal to the 7th pair of somitomeres at the expense of the eighth pair of somitomeres.
6
Q
How many pairs of somitomeres are kept constant at the caudal end of the paraxial mesoderm?
A
11 pairs
7
Q
What is the wavefront mechanism?
A
opposing gradients of FGF-8 and retinoic acid, controlled by MESP-2, the causes the differentiation of somites, called somitogenesis.
8
Q
What is the segmentation clock?
A
leads to the pattern for the somite formation.
9
Q
What are the TF in segmentation clock?
A
Lunatic fringe and C-hairy, which are TF on Hox genes, and the receptors are EphA and EphB
10
Q
What are the proteins that result in the fissure between the two adjacent somites.
A
Cells at anterior expressed EPHA, the receptor.
Cells at the posterior express EPHB, the ligand.
11
Q
What divides the borders between adjacent somites?
A
Lunatic fringe (anterior - Eph A) and C hairy (posterior - Eph B)
12
Q
What is the TF involved in differentiation of the ventral part of the somite?
A
shh
13
Q
What is the TF involved in differentiation of the dorsal part of the somite?
A
wnt
14
Q
What separates dermomyotomes into dorsal and ventral myotomes?
A
Pax 3, Pax 7, and paraxis
15
Q
Dermomyotomes differentiate into what two things?
A
dermis and skeletal muscle
16
Q
What inhibits BMP-4
A
noggin
17
Q
Hox genes are involved in what?
A
cranial/caudal differentiation
18
Q
What does intermediate mesoderm respond to?
A
BMP and activin
19
Q
What does intermediate mesoderm express
A
Pax2
20
Q
What type of mesoderm is associated with pronephros and mesonephros?
A
intermediate mesoderm
21
Q
Cells migrating through the anterior primitive streak form what?
A
form outflow tract (vena cava and aorta)
22
Q
Cells migrating through the middle primitive streak form what?
A
form ventricles
23
Q
Cells migrating through the posterior primitive streak form what?
A
form atria
24
Q
What cells form the cardiac crescent?
A
cells migrating through the anterior, middle, and posterior primitive streak.
25
What signaling molecules cause the formation of the cardiac crest?
BMPs and FGFs
26
From what does the cardiogenic plate arise?
Splanchnic mesoderm
27
proepicardium primordium is the source of what non cardiac cells?
pericardium and myocardial fibroblasts
28
Why is the oropharyngeal opening formed?
Because there is contact between the ectoderm and endoderm with no mesoderm in between them.
The lack of mesoderm forms the oropharyngeal opening.
29
Initial signaling for endoderm formation occurs during gastrulation and depends on what?
nodal, signaling molecule.
30
What are the three circulatory arcs of the 4 week embryo?
Vitelline, allantoic, and embryonic
31
All extraembryonic tissues have what germ layer?
mesoderm
32
Amnion and chorion consists of what germ layers?
Mesoderm and ectoderm
33
Yolk sac and allantois consists of what germ layers?
Endoderm and mesoderm
34
What are the characteristics of the previllous embryo?
no villi
35
What are the characteristics of the primary villous embryo?
ectodermal
36
What are the characteristics of the secondary villous embryo?
mesodermal
37
What are the characteristics of the tertiary embryo?
appearance blood vessels
38
What are villi that are anchored to the cytotrophoblastic shell?
anchoring villi
39
Villi increase what?
surface area
40
The lumen of the uterus is called what?
decidua parietalis, comes from lateral plate mesoderm.
41
What are the functions of the placenta?
diffusion of oxygen and carbon dioxide, diffusion of foodstuffs, excretion of waste products.
42
What are the characteristics of the early placenta?
Thick, permeability low, small surface area, and diffusion conductance is minuscule.
43
What are the characteristics of the late placenta?
Thin, permeability high, large surface area, and large increase in placental diffusion.
44
What is the PO2 of the mother and fetus near the end of pregnancy?
50 and 30, respectively
45
What is the reason why adequate oxygenation can occur with such low pressure gradient?
Bohr effect
46
When is HCG measurable?
8-9 days after ovulation
47
What is HCG secreted by?
syncytial trophoblast cells (into maternal fluids)
48
When is the maximal secretion of HCG?
10-12th week of pregnancy
49
What is the function of HCG?
Causes corpus luteum to increase section of progesterone and estrogens.
50
What is the main source of progesterone?
The placenta
51
What are the functions of progesterone?
Causes decidual cells to develop in the endometrium
Decreases contractility of pregnant uterus
Increases secretions of fallopian tubes and uterus
May work with estrogen to prepare breasts for lactation
52
When does HCS begin to be secreted?
beginning of week 5
53
What are the functions of HCS?
to get glucose to fetus.
Causes decreased insulin sensitivity and decrease utilization of glucose by mother.
General metabolic hormone
54
The placenta is highly permeable to alcohol and excessive ingestion can produce what defect in the fetus?
Fetal alcohol syndrome
55
What happens in erythroblastosis fetalis?
hemolysis of fetal RBC
56
What is hydrops fetalis?
edema in fetus. water accumulation in fetus
57
Placenta previa?
abnormal implantation of the embryo, causing a mechanical block of the birth canal. This is a "disruption"
58
Hydatidiform mole?
Swellings of the chorionic villi, caused by maternal imprinting.
59
Malformations?
primary errors of morphogenesis. they are usually multifactorial, involving etiological agents including genetic and env factors.
60
Disruptions?
disturbances in otherwise normal morphogenetic processes. Ex amniotic bands
61
Deformations?
disturbances in otherwise normal morphogenetic processes. Typically cases by abnormal biochemical forces such as uterine constraints. Ex clubfoot
62
Sequences?
a series (cascade) of events triggered by one initiation factor. Ex is oligohydramios (decreased amniotic fluid) which leads to a variety of events, including fetal compression and other problems stemming from the fetal compression.
63
Syndromes?
constellations of congenital anomalies that are thought to be pathologically related but cannot be explained on the basis of a single local initial event, but are often caused by a single event.
64
Turner's syndrome
One X.
Female with underdeveloped sex characteristics, low hairline, broad chest, folds on neck, usually sterile, usually of normal intelligence.
65
Poly X syndrome
```
Several X (XXX)
Usually tall and thin, often fertile, most have normal intelligence.
```
66
Thalidomide
No or malformed limbs
67
Alcohol
Fetal alcohol syndrome
68
Retinoic acid
incorrect hox gene differentiation
69
Folic acid
anencephaly and spina bifida
70
What are maternal factors resulting in fetal growth restrictions?
Preeclampsia, chronic hypertension, maternal use of drugs/alcohol/nicotine, and maternal malnutrition.
71
What is fetal hydrops?
accumulation of edema fluid int he fetus during intrauterine growth
72
What is the most common cause of hemolytic anemia until recently, between mother and fetus?
blood group and incompatibility
73
What is immune hydrops
hemolytic anemia caused by blood group incompatibility.
74
What is the cause of non-immune hydrops
chromosomal abnormality
75
What is kernicturus?
High levels of bilirubin in the blood, so much so that it moves out of the blood into the brain, causing brain damage.
76
In order for the intermediate layer of the epidermis to form, the inactivation of what needs to occur?
p63 via MIR-203
77
What are the two sublayers of intermediate layer of the epidermis and what is significant about them?
stratum spinosum, the appearance of keratohyalin granules
| stratum granulosum, interconnected by fillagrin.
78
What causes the three layers of epidermis to form?
Activation of p63
79
When is the periderm formed?
formed by the end of the first month
80
When is the three-layered epidermis formed?
formed by the end of the third month
81
Apoptosis happens during what time?
sixth month
82
Where are melanoblasts and merkel cells derived from?
neural crest
83
Where are Langerhan's cells derived from?
bone marrow
84
What is significant about immigrant cells?
they are not developed in the epidermis but migrate there.
85
What is instructive induction?
one germ layer instructing another germ layer how to differentiate.
86
What are the epidermal derivatives?
hair nails mammary glands
87
hair nails mammary glands are developed by interactions of what germ layers?
ectodermal-mesodermal
88
What contributes to the hair follicle, hair shaft, sebaceous glands, nails, eponychium, hypochium, and secretory components of mammary?
ectoderm
89
What contributes to the hair papilla, outer hair follicle and arrector muscle?
mesenchyme/mesoderm
90
What is the function of estrogen in regards to mammary glands/ducts?
stimulation of duct growth
91
What is the function of progesterone in regards to mammary glands/ducts?
stimulation of formation of secretory alveoli
92
What is the function of prolactin in regards to mammary glands/ducts?
Milk protein and fat synthesis
93
What is the function of oxytocin in regards to mammary glands/ducts?
Milk letdown
94
Common pathway of bone/cartilage differentiation uses what?
TGF-B
95
Membranous pathway of bone/cartilage differentiation uses what?
Runx-2 and Osx
96
Permanent cartilage pathway of bone/cartilage differentiation uses what?
Sox-9
97
Endochondral bone pathway of bone/cartilage differentiation uses what?
Runx-2, ihh, BMP-6
98
From what is the centrum derived?
ventral and medial sclerotomes
99
From what are the neural arches derived?
dorsal regions of sclerotomes
100
From what are the costal processes/ribs derived?
```
proximal = myf5 and myf6
distal = BMP
```
101
From what Hox gene is occipital-cervical boundary derived?
Hox 3
102
From what Hox gene is cervical-thoracic boundary derived?
Hox 6
103
From what Hox gene is attached-floating ribs boundary derived?
Hox 9
104
Single Hox gene knockouts?
when a single Hox genes are knocked out, only minor morphological effects are noted. When all the members of a paralogous group are inactivated, however, profound effects appear.
105
Knockout of all hox 10 paralogues?
when all the Hox10 paralogues are knocked out, ribs form on all the lumbar and sacral vertebrae. This finding suggests that hox10 represses the influence of the more anterior Hox genes. without hox 10 lumbar vertebrae are not formed.
106
Knockout of all hox 11 paralogues?
suppresses the influence of hox10 and allows the sacrum to form. One of the striking features of axial development is the redundancy of the genes that pattern the vertebrae. Without hox 11 sacral vertebrae are not formed.
107
Mutation of single Hox gene?
a mutant of a specific hox gene is likely to produce only a minor anatomical defect, whereas the non-function of an entire paralogous group produces major effects.
108
What Hox gene do you need to form a normal Atlas/Axis joint?
HoxA7
109
What happens when HoxA7 is knocked out?
A proatlas is formed and stays around and no Dens is formed.
110
What is one of the first bones to become ossified, arises from neural crest, and follows intramembranous pathway?
Clavicle
111
The cartilaginous portion of the viscerocranium forms what?
pharyngeal arch I and II
112
What are the two subdivisions of the viscerocranium?
Cartilaginous portion and membranous portion (which forms the bones of the face)
113
Ossification centers form within the cartilage allow continued growth and are separated from each other by synchondroses. Elongation of primary ossification centers is due to what?
shh
114
What is expressed in all sutures?
Noggin
115
What TF closes sutures?
BMP
116
What TF inhibits BMP so sutures dont close prematurely?
noggin
117
What is the name for the intersection of more than two bones?
fontanelles
118
Where do all skeletal muscles originate?
somites or somitomeres
119
Are myogenic cells mitotic or postmitotic?
mitotic
120
Are myoblast cells mitotic or postmitotic?
postmitotic
121
At what point are nuclei moved to the periphery?
myotubes
122
In what stage of skel musc development do myoblasts line up and adhere to one another?
myotubes
123
What forms muscle fibers?
myotubes
124
What cells are mitotic and myogenic, and can add to existing myofibers but they cannot make new ones?
satellite cells
125
What cell replace damaged muscle by proliferating, fusing, and differentiating into skeletal muscle fibers?
satellite cells
126
Satellite cells become mitotic in times of stress because of what?
C-Met receptor is the binding site for hepatic growth factor. HGF binds C-Met.
127
What transcription factors allow myogenic cells to remain mitotic?
FGF and TGF-B
128
What transcription factors stops mitotic activity in myogenic cells?
p21
129
What family of TF is able to convert non-muscle cells to cells capable of expressing muscle proteins?
MyoD family
130
What genes separately can activate MyoD and cause myogenic cells to become myoblasts in somites?
Pax3 and Myf5
131
MyoD causes the formation of what genes?
myoblast genes
132
Tendons of hypaxial muscles and limb muscles arise from where?
Lateral plate mesoderm
133
Where do hypaxial muscles arise from?
ventral buds of myotome
134
Where do epaxial muscles arise from?
dorsal lip of myotome
135
Where do epaxial tendons arise from
syndetome layer within somites.
136
Muscles of the head and neck are derived from where?
paraxial somitomeres
137
Musculature from the lower jaw is derived from where?
splanchnic mesoderm
138
T/F: There are no somite around the head/neck region.
True
139
Cardiac muscle is derived from where?
splanchnic mesoderm
140
How are early cardiac muscle cells able to maintain their ability to divide?
by partially disassembling their contractile apparatus prior to cell division.
141
What are the parts oft he tripartite brain? At what time?
Prosencephalon, Mesencephalon, and Rhombencephalon. Four weeks
142
What are the parts of the pentapartite brain? At what time?
Telencephalon and Diencephalon (from Prosencephalon), Mesencephalon (from Mesencephalon), Metencephalon and Myelencephalon (from the Rhombencephalon).
143
In what stage does the limiting membrane occur?
early neural tube wall
144
What type of epithelium is found in the late neural tube wall?
stratified epithelium.
145
If the metaphase plate is parallel, what occurs?
the daughter cell closest to the lumen remain proliferative and the daughter cell further from the lumen becomes a neural blast (which gives rise to neurons).
146
If the metaphase plate is perpendicular, what occurs?
both daughter cells become proliferative
147
Ventral signaling
shh
148
Dorsal signaling
BMP, Pax 3, 7, and snail-2
149
Where is the isthmic organizer located and whats its function?
it is a signaling center between the mesencephalon and the metencephalon
150
What is the principle signaling molecule of Isthmic organizer and what genes does it act on?
FGF8/Wnt1 which induce the expression of EN1, EN2, Pax2, and Pax5
151
T/F: shh restricts Pax.
True
152
What prosomeres define the diencephalon?
P1-P3
153
What prosomeres define the dorsal and ventral thalamus?
P2-P3
154
What field is a large area of the forebrain and represents the prechordal region of the neural tube?
secondary rhombencephalon.
155
What is the growth pattern of motor axon outgrowth?
growth begins in the spinal cord and grow towards the periphery.
156
Where are the cell bodies of sensory neurons derived?
neural crest cells
157
How do sensory neuron axons grow?
toward the spinal cord and towards the periphery
158
What determines whether migrating neural crest cells differentiation into autonomic neurons or other neural crest derivatives?
BMPs
159
Are Sympathetic or Parasympathetic cells typically adrenergic?
Sympathetic
160
Are Sympathetic or Parasympathetic cells typically cholinergic?
Parasympathetic
161
Where do the symapthetic preganglionic motor neurons arise from?
intermediate (lateral) horns of gray matter
162
T/F: Sympathetic postganglionic motor neurons are myelinated.
False
163
Where are radial glial cells located?
in the ventricular zone
164
Radial glial cells are a subdivision of what type of cell?
astrocytes
165
What is the major topographical change in the myelencephalon?
pronounce expansion of the roof plate to form the thin roof over the fourth ventricle.
166
What is a segmentation gene that is involved in the formation of rhombomeres 3 and 5
Krox 20
167
Expression of which set of genes seems to be responsible for the differentiation of specific nuclei in the myelencephalon?
Hox genes
168
What are the derivatives of the metencephalon?
pons (basal plate) and cerebellum (alar plate)
169
T/F: granule cells and purkinje cells have opposing migratory routes.
True
170
What type of cells migrate anteriorly along dorsal region of Rhomomere 1 and interiorly through purkinje layer?
granule cells
171
What type of cells migrate radially through granule cells?
purkinje cells
172
What are the three patterning centers in the forebrain?
Rostral patterning center (FGF8)
Dorsal Patterning center (BMPs Wnts)
Ventral patterning center (Shh)
173
What are the major derivatives of the alar pates of the mesencephalon?
tectum (superior and inferior colliculi)
174
Where is Otx-2 located and how is it related to shh?
it confines shh to the basal part of the midbrain
175
Where do the cerebral peduncle form and what is their function?
ventrolateral region of the mesencephalon
| they carry fibers between the cerebral hemispheres and the spinal cord.
176
Derivatives of diencephalon?
thalamus-es
