Exam II Qs Flashcards
1
Q
An increase incidence of what condition is strongly associated with increase in maternal age?
Trisomy 21 Trisomy 18 Trisomy 13 Anencephaly Ambiguous external genitalia
A
Trisomy 21
2
Q
Cleft palate is a result in a defect in what developmental mechanism?
Failure to fuse Failure to merge Faulty inductive tissue interaction Disturbance in tissue reabsorption Absence of normal cell death
A
Failure to fuse
3
Q
Which condition is related to maternal imprinting?
Accessory placental lobes Placenta previa Oligohydramnios Single umbilical artery Hydratidform mole
A
Hydratidform mole
4
Q
Phocomelia is most likely to be seen after maternal exposure to which teratogenic agent during first trimester of pregnancy?
Alcohol Aminopterin Androgens Ionizing radiation Thalidomide
A
Thalidomide
5
Q
The most serious threat of hydrop fetalis is CNS damage. The affected brain is enlarged and edematous, and when sectioned has a bright yellow color, particularly basal nuclei, thalamus, cerebellum, and cerebral gray matter, and spinal cord. The CNS damage is known as which of the following? Erythroblastosis fetalis Kernicterus Phenylketonuria Galactosemia
A
Kernicterus
6
Q
What is the initial initiator of future forelimb development? Hoxd Tbx5 Shh Gli3
A
Tbx5
7
Q
A high concentration in amniotic fluid results in neural tube defects? Lecithin Alpha fetoprotein Kernicterus Creatinine
A
Alpha fetoprotein
8
Q
The most serious threat of hydrop fetalis is CNS damage. The affected brain is enlarged and edematous, and when sectioned has a bright yellow color, particularly basal nuceli, thalamus, cerebellum, cerebral gray matter and spinal cord. The CNS damage is known as which of the following?
Erythroblastosis fetalis
Kernicterus
Phenylketonuria
Galactosemia
A
Kernicterus
9
Q
The sclerotome arises from cells that were located in which of the following locations
Notocord
Paraxial mesoderm
Intermediate mesoderm
Lateral mesoderm
A
Paraxial mesoderm
10
Q
The cardiogenic plate arises from where?
Embryonic endoderm Somatic mesoderm Splanchnic mesoderm Intermediate mesoderm Neural crest
A
Splanchnic mesoderm
11
Q
An inductive stimulus from which structure stimulates the transformation of the epithelial sclerotome into secondary mesenchyme?
Neural crest Somite Ectodermal placodes Embryonic endoderm Notochord
A
Notochord
12
Q
Intermediate mesoderm is the precursor of the:
Urogenital system Heart Somites Body wall Vertebral bodies
A
Urogenital system
13
Q
Name the 4 stages in the development of the chorionic villi, state characteristics of each
A
- Previllous embryo - no villi via trophoblast
- Primary villous stage - solid, cytotrophoblastic, ectodermal primary villi appear
- Secondary villous - mesodermal cores appear within primary villi
- Tertiary villous stage - blood vessels within mesenchymal core of secondary villi
14
Q
What tissue in the mature placenta directly interfaces with the maternal uterine connective tissue?
Cytotrophoblast cells Syncytiotrophoblast cells Trophoblast cells Decidual cells None of the above
A
Cytotrophoblast cells
15
Q
Describe the location of the chorionic plate in the mature placenta
A
(mesoderm) faces away from the chorionic villi towards the chorionic cavity
16
Q
Describe the location of the cytotrophoblast shells in the mature placenta, what are they formed by?
A
Formed by expansion of the cytotrophoblastic columns over the maternal decidual cells
17
Q
List the 5 structures involved in the final development of the placenta
A
Cytotrophoblast Cytotrophoblast columns Cytotrophoblast shells Anchoring villi Chorionic plate
18
Q
What are the anchoring villi of the mature placenta anchored to?
A
The cytotrophoblastic shell (as opposed to floating villi)
19
Q
What maternal tissues are lost at childbirth? (3)
A
Decidua capsularis
Chorion laevae
Amnion
20
Q
What is the fate of the decidua capsularis?
A
Undergoes atrophy
21
Q
Distinguish between early vs. late placenta
A
Early:
Thick, low permeability, small SA, total diffusion conductance is miniscule
Late:
Thin, high permeability, large SA, large increase in placental diffusion
22
Q
State the oxygen pressure gradient near the end of pregnancy of the mother and fetus
A
PO2 mother = 50mmHg
PO2 fetus = 30mmHg
23
Q
How does adequate oxygenation occur with such a low pressure gradient near the end of pregnancy?
A
Fetal Hb has a greater affinity for O2
Fetal blood has more Hb than mother (50%)
Bohr effect
24
Q
Define Bohr effect
A
Hb can carry more O2 at a low PCO2
Curve is shift left for fetal, right and down for maternal
25
Define the double Bohr effect
The double shift in the maternal blood and fetal blood
26
Where is hCG secreted from, when, and what is its function?
Via syncytial trophoblast cells into maternal fluids
Measurable at 8-9d after ovulation, max = 10-12w pregnancy
Prevents degradation of corpus luteum & give growth
Causes CL to secrete more progesterone & est
Exerts interstitial cell-stimulating effect on testes of male fetus = testosterone production
27
Where is estrogen secreted from, when, and what is its function?
Syncytiotrophoblast cells of placenta
Toward end of pregnancy, 30X more via androgenic steroid compounds (mom&fetal adrenal glands) Converted by trophoblast cells into estradiol, estrone, and estriol
Uterine, breast, external genitalia enlargement
Breast ductal growth
Relaxation of pelvic ligaments
28
Where is progesterone secreted from and what is its function?
Small quantities = corpus luteum
Large quantities = placenta
Causes decidual cells to develop in the endometrium
Decreases contractility of pregnant uterus
Increases secretions of fallopian tubes and uterus
May work w/ est to prepare breast for lactation
29
When is human chorionic somatomammotropin secreted and what is its function?
5th week
Decreased insulin sensitivity and decreased utilization of glucose by mother
General metabolic hormone
30
Define malformation
Primary errors of morphogenesis.
Usually multifactoral, involving a number of etiological agents like genetic and environmental factors
31
Define disruption, what's an example?
Disturbances in otherwise normal morphogenetic processes
i.e. amniotic bands
32
Define deformation, what makes it different from disruption? Give an example
Distrubances in otherwise normal morphogenetic processes
Typically caused by abnormal biomechanical forces = uterine constraints
i.e. clubfoot
33
Define sequences
A series/cascade of events triggered by one initiating factor
i.e. oligohydramnios which leads to a variety of events (bilateral renal agenesis)
34
Define 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
Often caused by a single event i.e. virus
35
Explain why developmental insults during the first 3 weeks of development are unlikely to result in defective development
The insults either kill the embryo or are compensated for by the powerful regulatory properties of the early embryo
36
Effects of thalidomide?
Limb defects, ear defects, cardiovascular anomalies
Phocomelia (mermaid), amelia
37
Effects of alcohol? What are the characteristics of fetal alcohol syndrome?
Growth and mental retardation, microcephaly, face and trunk malformations, heart defects
Holoprosencephaly = severe
38
Effects of RA
Cranial neural crest problems; facial structures, outflow tract of heart and thymus
39
Effect of folic acid
Neural tube defects = Anencephaly, growth retardation, cleft lip and palate, hydrocephaly, hypoplastic mandible, low set ears
40
What is surfactant? Function? How does it related to neonatal respiratory distress syndrome. Why is this referred to as hyaline membrane disease?
Protein and lipid component that coats walls of alveoli, so when lungs collapse they do not stick together
Hyaline membrane disease = bc it affects the respiratory membranes
41
Define fetal hydrops, what is the cause?
The accumulation of edema fluid in fetus during intrauterine growth due to bilirubin being released and causing water accumulation
Hemolytic amenia due to blood group incompatibility = immune hydrops
Nonimmune hydrops via cardiovascular defects and arrhythmias
42
What is the major factor in immune hydrops when the fetal blood mixes with maternal blood?
D Antigen of the Rh group
Blood mixes during last trimester or during birth
ABO incompatibility not an issue bc maternal Ab removes incompatible fetal RBCs that cross placenta
43
What is the major cause of nonimmune hydrops?
Cardiovascular defects = congenital cardiac defects and arrhythmias
44
What are the chromosomal anomalies that are associated with nonimmune hydrops?
Turner syndrome and trisomies 18,21 due to cardiac structural aberrations that accompany these anomalies
45
Define kernicturus and describe the consequences
Related to fetal hydrops
Results in CNS damage; enlarged and edematous brain that's bright yellow color when sectioned
46
Define pregnancy-induced hypertension, at what week of pregnancy does it developed?
Persistent elevated bp (140/190) that develops after 20 weeks of gestation and returns to normal after birth
47
Define preclampsia, what are the symptoms?
Severe case of preclampsia
Higher BP
Proteinuria
Weight gain
Edema
48
Define Eclampsia, symptoms?
Most serious condition from preclampsia
Fatal
Grand mal seizures or coma
49
List the 3 immigrant cells, where they're derived from and function
MML - Many Messicans Live
M - melanoblasts - via neural crest, migrate into dermis then epidermis, produce pigment mid-pregnancy
M - Merkel cells - via neural crest, slow-adapting mechanoreceptors
L - Langerhans - via BM, APCs
50
What is derived from the ectoderm during the development of hair?
Sebaceous glands
Part of follicle
Hair shaft
51
What is derived from the mesoderm during the development of hair?
Arrector pili
52
State the role of these hormones in mammary gland development:
Est
Prog
Prolactin
Oxytocin
Est = duct system growth
Prog = formation of secretory alveoli
Prolactin = synthesis of milk protein and fat
Oxytocin = causes milk letdown
53
What are the 4 bone/cartilage differentiation pathways?
CEMP
Common
Endochondral
Membranous
Permanent
54
What skeletal tissue is derived from mesodermal sclerotomes of somites?
Vertebral column - (Hox genes important)
Ribs
Sternum
55
What skeletal tissue is derived from lateral plate mesoderm?
Limb bones
| Girdles
56
What skeletal tissue is derived from Head mesoderm?
Calvaria and base of skull
57
What skeletal tissue is derived from neural crest?
Facial bones
58
List the 3 subdivisions of the developing skull?
Neurocranium
Viscerocranium - via neural crest; mainly branchial/pharyngeal arches
Occipital sclerotomes
59
What does the neurocranium surround? What two portions is it made up of? and what do they give rise to?
Part of skull that surrounds the brain
Cartilaginous portion - TESO. occipital, sphenoid, ethmoid, and parts of temporals (base of skull)
Membranous portion - TPFO occipital, parietals, frontals, parts of temporals (usually flat bones)
60
What does the viscerocranium surround? What two portions is it made up of? and what do they give rise to? Which CN does the pharyngeal arches give rise to?
Surrounds oral cavity and pharynx
Cartilaginous portion - Pharyngeal arch I CN V (meckel's cartilage, malleus, incus) Pharyngeal arch II (Reichert's cartilage, stapes, styloid)
Membranous portion - CN VII part of temporal, zygomatic, maxillary, nasal, lacrimal, palatine, vomer, pterygoid plates, mandible, tympanic ring
61
What are the four components of each pharyngeal arch?
Skeletal
Muscle
A branch of a specific CN
Artery
62
What signaling molecule is expressed in all sutures? What does it inhibit?
Noggin; suppresses BMP which leads to closure of sutures
63
What signaling molecule causes the elongation of primary ossification centers?
Shh; ossification centers are separated by synchondroses
64
List characteristics of myogenic cells
Originate in somites
Restricted to muscle-forming line
Mitotic cells
65
List characteristics of myoblasts
Derived from myogenic cells
| Postmitotic
66
List characteristics of myotubes
Formed when myoblasts line up and adhere to each other
Actin, myosin, troponin, tropomyosin, actin
Formation of myofibrils w/ sarcomeric arrangement
Nuclei move to periphery
67
Differentiate between primary and secondary myotubes; how are primary ones formed, when does differentiation occur? Where are secondary ones formed?
Primary - formed by the fusion of earliest/embryonic myoblasts, differentiation occurs before innervation
Secondary - smaller than primary, formed alongside primary from late/fetal myoblasts
Motor axons may be required to form these
Contained within same basal lamina and are electrically coupled
68
Function of satellite cells?
B/w sarcolemma and basal lamina of myofiber
Mitotic and myogenic
Able to fuse with muscle fiber and provide growth
Do not form new muscle fibers, only assist existing ones
69
Where do epaxial muscles and tendons arise from?
Muscles - dorsal lip of myotome
Tendons - syndetome layer within somites
70
Where do hypaxial muscles and tendons arise from?
Muscles - ventral buds of myotome
Tendons - lateral plate mesoderm
71
Where do limb bud muscles and tendons arise from?
Ventrolateral dermomyotome
72
Where does muscles of the head and neck derive from?
Paraxial somitomeres
73
Where are extraocular muscles derived from?
Prechordal plate
74
Where is most cranial musculature derived from? Including lower jaw? How about cardiac muscle?
Most cranial - unsegmented paraxial mesoderm
Lower jaw - splanchnic mesoderm
Cardiac muscle - splanchnic mesoderm (early cells don't express MyoD)
75
Limb field vs. Limb disc; what happens is limb disc or limb field is removed?
Limb field surrounds the limb disc.
limb disc is removed, a limb will develop
If limb field is removed = no limb will form
76
Result if you remove half the limb disc
The remaining half will form a complete limb
77
Result if you vertically divide the limb disc into two halves and physically separate the two halves
Each half will form a normal limb
78
Result of you fuse two limb discs together
A single normal limb will form
79
Result if you transplant a limb disc to the opposite side? (Experiments on Axes Formation)
AP axis is reversed but not the DV axis
Normal limb will form with AP axis reversed
80
Result when you rotate a limb disc 180 degrees (Experiments on Axes Formation)
Both AP axis and DV axis will be reversed
Normal limb bud will form with only AP axis reversed
81
Result when you transplant a strip of flank tissue from just posterior to the limb disc to an ectopic site just anterior to the limb disc (Experiments on Axes Formation)
Resulting limb contains two posterior halves arranged in a mirror-image fashion
Conclusion: the strip of flank tissue just posterior to the limb disc organized the posterior edge of the disc
82
List the 3 axes that form in early limb bud development
Anteroposterior
Dorsoventral
Proximodistal
83
What are the effects of limb mesoderm on overlying ectoderm, if AER is mutant? What is this an example of? What is the role of AEMF (apical ectodermal maintenance factor) and who produces it?
Instructive induction
Normal wing bud mesoderm combined w/ mutant AER ectoderm fails to produce an AER
AEMF = maintains AER in healthy state, produced by mesoderm; AER maintains mesodermal cells below it in labile and mitotic state
84
Function of apoptosis in limb bud development?
"carves" the shape of the limb, including the separation of the digits
85
Where are limb bud mesenchyme cells derived from? What do they give rise to?
Via lateral plate mesoderm
Appendicular parts, connective tissue, some blood vessels
86
What do hypertrophic cells related to mesenchymal cell and cartilage formation express?
Indian hedgehog = ihh
87
What causes the restriction of cartilage formation to the central core of the limb bud?
Wnt-7a in the overlying limb bud ectoderm
88
Axons originating from more medial locations in spinal cord grow into the ___________ muscle mass.
Axons originating from more lateral locations in spinal cord grow into the __________ muscle mass
Ventral muscle mass
Dorsal muscle mass
89
Result if the forelimb rudiment of a salamander embryo is removed so that the limb fails to develop? (Motor Axon Guidance Studies)
Nerves of the brachial plexus remain smaller/thinner than they would have if limb was still there
Spinal ganglia 3-5 also smaller, number of cells in each ganglion may be reduced by as much as 50%
90
Result if an additional limb rudiment is transplanted to the flank of a salamander embryo? (Motor Axon Guidance Studies)
The local spinal nerves supply the innervation to the transplanted limb and these local nerves increase in thickness
Ganglia associated with these nerves increase in size; up to 40%
91
Result if the forelimb rudiment of an amphibian embryo, prior to the outgrowth of nerves is cut out and transplanted to a position very near the original one? (Motor Axon Guidance Studies)
The brachial nerves will deviate from their normal paths and will be deflected in the direction of the transplanted limb.
If distance is not too far, the brachial nerves will penetrate into the limb and ramify and limb is fully functional
92
Result if an additional limb is transplanted into the immediate vicinity of the host limb? (Motor Axon Guidance Studies)
The brachial nerves will develop branches running out to the additional limb and will supply it
93
Result if the normal path of the nerves is blocked by some obstacle? (Motor Axon Guidance Studies)
The outgrowing nerves may avoid the obstacle, go around it, and still reach their normal destination.
Hamburger inserted a piece of mica into a frog embryo b/w the spinal cord and the region where the hindlimb rudiments were to develop. The nerves formed loops around the mica plate and still reached the hindlimb rudiments
94
Result if the limb rudiment is placed farther away from the normal limb site, or if the obstacle b/w the spinal cord and the limb rudiment is too great? (Motor Axon Guidance Studies)
The nerve fibers fail to be attracted to the limb
If limb rudiment is placed on the flank of the embryo, it will attract the local spinal nerves. These nerves will grow into the limb, but can't provide for the normal limb function.
Only the areas of the spinal cord form which the nerves of the brachial and lumbar plexuses originate possess the properties necessary for controlling the functioning of the limbs
95
Result if an eye was transplanted into the side of an embryo after the forelimb rudiment was removed? (Motor Axon Guidance Studies)
The brachial nerves were deflected from their normal path and grew out toward the transplanted eye.
At the eye, they fail to penetrate into the eye and make a connection
Attraction of the outgrowing nerves to peripheral organs is unspecific. Connections b/w a nerve and the end organ can be made only if the two correspond to each other
96
What adult structure develops from the telencephalon?
CNP
Corpus striatum
Neocortex
Paleocortex
97
What adult structure develops from the diencephalon
Epithalamus
Thalamus
Hypothalamus
Infundibulum
98
What adult structure develops from the mesencephalon?
CTT
Tectum
Tegmentum
Cerebral peduncles
99
What adult structures develop from the metencephalon?
Cerebellum
| Pons
100
What adult structure develops from the myencephalon?
Medulla
101
What happens if daughter cells in the neural tube have a metaphase plate that is parallel to the inner margin of the neural tube?
Daughter cell closest to lumen = remain proliferative
Daughter cell further = expresses Notch receptor, becomes postmitotic, moves to external limiting membrane, becomes a neuroblast (pre-neuron)
102
What happens if daughter cells in the developing neural tube have a metaphase plate that is perpendicular to the inner margin of the neural tube? (next to lumen)
Two resulting daughter cells will remain proliferative
103
Which is the principal signaling molecule during the regional differentiation of the neural tube in the isthmic organizer region?
```
En-1
Wnt-1
FGF-8
Pax-2
Pax-5
```
FGF-8
104
What signaling molecule primarily is involved with the dorsoventral patterning of the midbrain?
Shh = located ventrally
105
What local environment factors influence axon guidance? (4)
Chemoattraction
Contact attraction
Chemorepulsion
Contact repulsion
106
What microenvironment cues dictate axon guidance?
Caudal half of somite
Fibronectin and laminin
Integrins
Cadherins
107
Where do sympathetic preganglionic motor neurons arise from?
Intermediate/lateral horns of gray matter (similar with somatic motor neurons from ventral horns)
108
Where does parasympathetic preganglionic motor neurons arise from?
Intermediate/lateral horns of gray matter OR from nuclei in hindbrain
109
Where do preganglionic axons synapse?
Cell bodies of postsynaptic sympathetic motor neurons within the ganglia
Note: anything outside neural tube is from neural crest
110
Where are autonomic ganglia and postganglionic autonomic neurons derived from?
BOTH Neural crest
Cholinergic differentiation factor is responsible for the conversion of postganglionic sympathetic neurons from the typical form to that used in the innervation of sweat glands
111
The prechordal plate plays an important role in regionalization of the:
```
Notochord
Forebrain
Embryonic mesoderm
Primitive node
Hindbrain
```
Forebrain
112
Which of these structures in the embryo is unsegmented?
Somitomeres
Neuromeres
Notochord
Somites
Notochord
113
Blood vessels associated with which structure enter the fetal component of the placenta?
```
Decidua basalis
Allantois
Amnion
Yolk sac
Decidua parietalis
```
Allantois
114
A 28yr old Rh-negative woman's second son is born severely jaundiced. Which characteristic most likely describes her first child?
```
Male
Female
Rh positive
Rh negative
Hydramnios
```
Rh positive
115
Which of the following is responsible for the largest percentage of congenital malformations?
```
Maternal infections
Chemical teratogens
Genetically based conditions
Ionizing radiations
Unknown factors
```
Unknown factors
116
Folic acid deficiency is now believed to be a major cause of what class of malformations?
```
Trisomies
Neural tube defects
Ambiguous genitalia
Polyploidy
Duplications
```
Neural tube defects
117
An increased incidence of what condition is strongly associated with increasing maternal age?
```
Trisomy 18
Trisomy 21
Trisomy 13
Anencephaly
Ambiguous external genitalia
```
Trisomy 21
118
Satellite cells of muscle are activated under which of these conditions?
```
Normal muscle fiber growth
Muscle fiber regeneration
Muscle fiber hypertrophy
All of the above
None of the above
```
All of the above
119
Which cellular component of the epidermis is a peripheral outpost of the immune system and functions to present Ags to other immune cells?
```
Merkel cells
Keratinocytes
Basal cells
Melanocytes
Langerhan cells
```
Langerhan cells
120
Which structure is mesoderm in origin?
```
Hair shaft
Mammary duct
Sebaceous gland
Arrector pili muscle
None of the above
```
Arrector pili muscle
121
Which myogenic regulatory factor is expressed latest in the development of a muscle fiber?
```
Myogenin
MyoD
MRF-4
Myf-5
Pax-3
```
MRF-4
122
In the let-down of milk during lactation, the myoepithelial cells contract in response to:
```
Progesterone
Oxytocin
Estrogens
Lactalbumin
Casein
```
Oxytocin
123
Which of the following molecules plays an important role in the determination of the dorsoventral axis of the developing limb?
```
Msx-1
Wnt-7a
Hoxd-13
Pax-1
FGF-8
```
Wnt-7a
124
What molecule is associated with myogenic cells migrating into the limb bud from the somites?
```
Shh
BMP-7
FGF-4
Pax-3
En-1
```
Pax-3
125
What is the principal function of the AER?
Stimulating outgrowth of the limb bud
Setting up the anteroposterior axis of the limb bud
Determining the specific characteristics of the ectodermal appendages of the limb
Determining the pattern of neural ingrowth into the limb
Attracting the subcutaneous plexus of capillaries in the limb bud
Stimulating outgrowth of the limb bud
126
In the developing limb the sonic hedgehog gene product is produced in the:
```
Progress zone
Region of interdigital cell death
ZPA
AER
Common muscle mass
```
ZPA
127
The connective tissue of the limb arises from the:
```
Paraxial mesoderm
Neural crest
Intermediate mesoderm
Somitic mesoderm
Lateral mesoderm
```
Lateral mesoderm
128
The formation of clubfoot is associated with:
```
A misplaced ZPA
Defective cellular migration from somites
Thalidomide
Oligohydramnios
A neural crest defect
```
Oligohydramnios
129
What molecule produced by the notochord is instrumental in inducing the floor plate of the neural tube?
```
Hoxa-5
RA
Pax-3
Msx-1
Shh
```
Shh
130
The cell bodies of the motoneurons of a spinal nerve arise from the:
```
Basal plate
Marginal zone
Floor plate
Roof plate
Alar plate
```
Basal plate
131
Rhombomeres are segmented divisions of the:
```
Forebrain
Midbrain
Hindbrain
Spinal Cord
None of the above
```
Hindbrain
