Embryology

Front 1

where does fertilization take place? implantation?

Back 1

fertilization-in the ampulla of the uterine tube
implantation- in the posterior wall of the uterus

Front 2

what 3 events must occur in order for fertilization to occur? describe the events and what enzymes are involved

Back 2

capacitation- glycoprotein coat and seminal plasma proteins are removed from membrane
acrosome rxn- release of hyaluronidase (penetrate corona radiate) and acrosin (penetrate zona pellucida) enzymes
zona rxn-change in properties of zona pellucida that make it impermeable to other sperm

Front 3

what does the sperm receptor bind with and where? what occurs?

Back 3

ZP3 in zona pellucida
causes release of acrosin

Front 4

what on sperm binds to egg after penetration of sperm? what occurs next and how?

Back 4

sperm membrane-bound fertillin alpha/beta to interact with oocyte plasma membrane via egg integrins and CD9
-rxn is Ca dependent exocytosis of cortical granules into perivitelline space and prevents other sperm from fertilizing

Front 5

what does penetrating sperm trigger in oocyte? when is the zygote formed?

Back 5

second meiotic division (egg had been arrested in metaphase)
-now referred to as zygote as it is 2N

Front 6

what occurs after the 8 cell stage? what is formed by day 3? day 4?

Back 6

after 8 cell stage, cells undergo compaction and become tightly associated with each other
-16 cell morula by day 3
-58 cell blasocyst day 4

Front 7

when does implantation occur? what structures are involved and describe process?

Back 7

day 5-6
at the inner cell mass of the blastocyst, attaches to endometrial epithelium at embryonic pole

Front 8

trophoblast cells proliferate rapidly and give rise to what?

Back 8

cytotrophoblast and syncytiotrophoblast layers
-syncytiotrophoblast penetrates endometrial epithelium and starts to invade stroma

Front 9

what layer of cells forms on surface of inner cell mass during implantation?

Back 9

hypoblast

Front 10

what is significant at day 9? what structures are evident and what are forming?

Back 10

implantation is almost complete
primary chorionic villi are evident and extraembyronic mesoderm is appearing

Front 11

when is implantation complete? what is visible?

Back 11

by 11-12 days, secondary villi are visible

Front 12

define transgenic

Back 12

injection of pronucleaus with a DNA fragment that becomes randomly incorporated into the cells genome

Front 13

define gene-targeting

Back 13

construction of DNA frament in such a wy that gene is not only incorporated into the genome but also replaces pat of the endogenous gene that matches specific regions of the DNA fragment

Front 14

what does the embryoblast differentiate in to in week 2?

Back 14

hypoblast and epiblast, 2 layers referred to as bilaminar embyronic disc

Front 15

what do the syncytiotrophoblast cells secrete and what is the function?

Back 15

-human chorionic gonadotropin which maintains activity of corpus luteum

Front 16

what gives rise to extraembryonic mesoderm? what does this surround?

Back 16

cells from yolk sac endoderm. surrounds amnion and yolk sac

Front 17

what form sites of mixing maternal blood and secretions from eroding uterine glands? how do nutrients pass to embryo?

Back 17

lacunae appear in syncytiotrophoblast
nutrients pass by diffusion as blood vessels are not yet formed

Front 18

what circular area of columnar cells develops from hyoblast cells in cranial end of embryonic disc?

Back 18

-prechordal plate
-indicates future site of the mouth

Front 19

after how long can hCg be detected in blood? in urine? what does high levels implicate? low?

Back 19

blood- 8
urine- 10
high- multiple pregnancies, hyatidiform mole, gestastional trophoblastic neoplasia
low- spontaneous abortion, ectopic pregnancy

Front 20

define gastrulation
what does it begin with? end with?

Back 20

bilaminar embryonic disc is converted into a trilaminar embryonic disc and marks beginning of morphogenesis
-begins with formation of primitive streak (from caudal end); ends with generation of 3 germ layers

Front 21

what occurs along primitive streak during start of gastrulation?

Back 21

cells of epiblast undergo epithelial-mesenchymal transformation and invaginate between epiblast and hypoblast
-becomes mesoderm

Front 22

what 2 places no mesoderm separating ectoderm from endoderm? what does it become?

Back 22

oropharyngeal
cloacal membrane
-becomes anus

Front 23

what are the functions of the notochord?

Back 23

-defines primordial axis of embryo and gives it some rigidity
-serves as basis for development of axial skeleton
-indicates future site of vertebral bodies
-induces overlying embryonic ectoderm to thicken and form neural plate
-specifies cells in ventral aspect of neural tube (floor plate)

Front 24

some neuroectodermal cells laying along side the crest of each neural fold transform into a mesenchymal phenotype which is what? what do they give rise to?

Back 24

neural crest cells
-give rise to sensory ganglia of spinal and cranial nerves

Front 25

what are the derivatives of ganglia?

Back 25

dorsal root, cranial nerves 5, 7, 9,and 10 and autonomic

Front 26

what are the derivatives of schwann cells

Back 26

ensheathing cells of the peripheral nervous system

Front 27

what are the derivatives of enteric (gut) nervous system

Back 27

odontoblasts, pia and arachnoid

Front 28

what are the derivatives of chromaffin cells

Back 28

adrenal medulla

Front 29

what are the derivatives of parafollicular c cells

Back 29

of thyroid

Front 30

what are the derivatives of melanocytes

Back 30

pigment cells in dermis

Front 31

what are the derivatives of aorticopulmonary septum

Back 31

development of septum between the aortic adn pulmonary valves

Front 32

what are the derivatives of pharyngeal arch skeletal components

Back 32

muscle, connective tissue, bone

Front 33

what are the derivatives of bones of neurocranium

Back 33

part of the skull enclosing the brain

Front 34

what does the paraxial mesoderm differentiate in to?

Back 34

paired cuboidal bodies- somites

Front 35

what derivatives of somites give rise to dermis, muscle, and form axial skeleton?

Back 35

-dermotome
-myotome (forms myoblasts)
-sclerotome

Front 36

what is lateral plate mesoderm divided in to?

Back 36

somatic mesoderm and splanchnic mesoderm

Front 37

somatic mesoderm adn overlying ectoderm are referred to what? this forms the embryonic wall

Back 37

somatopleure

Front 38

what are splanchnic mesoderm and underlying endoderm called?
this forms embryonic gut wall

Back 38

splanchnopleure

Front 39

what does intraembryonic coelom ultimately form?

Back 39

pericardial cavity, pleural cavity and peritoneal cavity

Front 40

at what day do blood vessels and blood islands begin forming? where?

Back 40

day 17
-extraembryonic mesoderm of yolk sac, connecting stalk and chorion

Front 41

define vasculogenesis

Back 41

formation of blood vessels from hemangioblasts, cells that have differentiated from splanchnopleuric mesoderm
-eg of EMT and MET

Front 42

define angiogenesis

Back 42

budding and sprouting of new vessels from existing angiolastic cords
-formation of new blood vessels from existing ones

Front 43

early stages of heart formation begin with formation of cardiogenic mesoderm aka

Back 43

cardiac crescent or cardiogenic plate

Front 44

what forms from cardiogenic mesoderm?

Back 44

paired regions of heart tubes that fuse in midline beneath foregut and generate a single heart tube

Front 45

when does development of the heart occur? when does it begin beating? what is its size?

Back 45

-20 days
-22 first heart beat
-2-3 mm

Front 46

when do primary chorionic villi appear and as what?

Back 46

days 11-13 as cytotophoblastic proliferations that bud into the overlying syncytiotrophoblast

Front 47

when are primary villi termed secondary? where do they form?

Back 47

after branching, the mesenchyme from extraembryonic somatic mesoderm grows into core
-form around entire chorionic sac

Front 48

when are secondary villi termed tertiary?

Back 48

once some of the mesenchyme differentiates into capillaries and visible blood vessels
-capillaries fuse to form arteriocapillary networks which soon become connected with embryonic heart via differentiated mesenchyme in core of chorion and connecting stalk

Front 49

what are the 3 main functions of placenta? what are eg of waste from fetus?

Back 49

metabolism, transport of gases and nutrients and endocrine secretion
-waste- co2, water, urea, uric acid, and bilirubin

Front 50

what type of tumor arises from remnants of primitive streak?

Back 50

sacrococcygeal teratoma

Front 51

what does prosencephalon give rise to? what do these structures give rise to?

Back 51

telencephalon-->corpus striatum
diencephalon-->thalmus, hypothalamus

Front 52

what does mesencephalon give rise to?

Back 52

midbrain

Front 53

what does rhombenecephalon give rise to? what do those structures give rise to?

Back 53

metencephalon-->cerebllum, pons
myelencephalon-->medulla

Front 54

neuroepithelial cells after several mitotic divisions differentiate into multi potential stem cells which further into what 2 cell lines?

Back 54

neuroblasts and glioblasts

Front 55

neuroblasts give rise to what?

Back 55

neurons

Front 56

glioblasts give rise to what?

Back 56

macroglia
-radial glial cells-->ependymal cells or astrocytes

Front 57

what are 2 types of macroglia cells?

Back 57

astrocytes and oligodendrocytes

Front 58

what do microglia derive from?

Back 58

monocytes (mesenchymal cells)- mesoderm

Front 59

what does prosencephalon give rise to? what do these structures give rise to?

Back 59

telencephalon-->corpus striatum
diencephalon-->thalmus, hypothalamus

Front 60

what does mesencephalon give rise to?

Back 60

midbrain

Front 61

what does rhombenecephalon give rise to? what do those structures give rise to?

Back 61

metencephalon-->cerebllum, pons
myelencephalon-->medulla

Front 62

neuroepithelial cells after several mitotic divisions differentiate into multi potential stem cells which further into what 2 cell lines?

Back 62

neuroblasts and glioblasts

Front 63

neuroblasts give rise to what?

Back 63

neurons

Front 64

glioblasts give rise to what?

Back 64

macroglia
-radial glial cells-->ependymal cells or astrocytes

Front 65

what are 2 types of macroglia cells?

Back 65

astrocytes and oligodendrocytes

Front 66

what do microglia derive from?

Back 66

monocytes (mesenchymal cells)- mesoderm

Front 67

what does prosencephalon give rise to? what do these structures give rise to?

Back 67

telencephalon-->corpus striatum
diencephalon-->thalmus, hypothalamus

Front 68

what does mesencephalon give rise to?

Back 68

midbrain

Front 69

what does rhombenecephalon give rise to? what do those structures give rise to?

Back 69

metencephalon-->cerebllum, pons
myelencephalon-->medulla

Front 70

neuroepithelial cells after several mitotic divisions differentiate into multi potential stem cells which further into what 2 cell lines?

Back 70

neuroblasts and glioblasts

Front 71

neuroblasts give rise to what?

Back 71

neurons

Front 72

glioblasts give rise to what?

Back 72

macroglia
-radial glial cells-->ependymal cells or astrocytes

Front 73

what are 2 types of macroglia cells?

Back 73

astrocytes and oligodendrocytes

Front 74

what do microglia derive from?

Back 74

monocytes (mesenchymal cells)- mesoderm

Front 75

region closest to central canal in neural tube
-what will it become?
-what cells populate it?

Back 75

ventricular zone (or ependymal layer)
-becomes future ventricular system
-epithelial cells populate

Front 76

what region of neural tube is later called germinal matrix in newborns? what type of cells does it contain?

Back 76

subventricular zone
-contains neuroblasts capable of dividing
0

Front 77

what what region of neural tube is also called mantle layer? what type of cells does it contain? what does this zone become?

Back 77

intermediate zone
-contains differentiating, post-mitotic neuroblasts
-becomes gray matter- contains cell bodies of neurons

Front 78

what zone of neural tube is characteristic of developing cerebral hemispheres? what type of cells does it contain? what does this zone become?

Back 78

cortical zone (or cortical plate)
-contains post mitotic cells which have migrated from sub ventricular zone
-becomes gray and white matter

Front 79

what zone of neural tube is farthest from central canal? describe its cells and what it is populated by
-what does it become?

Back 79

marginal zone (or cortical/marginal layer)
-contains few cells at beginning and is populated by axons and dendrites of developing neurons
-contains neuronal processes, but not cell bodies- becomes white matter

Front 80

what groove on each side of central canal and runs the length of neural tube? what does it divide the CNS in to?

Back 80

sulcus limitans
-dorsal region- alar plate
-ventral- basal plate

Front 81

what is the motor component of the spinal cord? sensory?

Back 81

motor- basal plate
sensory- alar plate

Front 82

what structures develop from alar plate? (3)
what structures develop from both alar and basal plate?

Back 82

telencephalon (cerebral hemispheres), diencephalon (thalamus) and cerebellum
-both- brainstem adn spinal cord

Front 83

when are the 2 growth spurts for cellular proliferation involving the brain?

Back 83

10-18 weeks after conception and between 30th week of gestation and 2 years of life

Front 84

describe neurons in newborns- how many neurons are produced compared to will populate mature brain? how are they pruned?

Back 84

50-100% more neurons than will populate mature brain are produced
-survival of neurons regulated by neurotrophins secreted by target cells by inhibiting apoptosis

Front 85

what cells are involved in cell migration?

Back 85

radial glial cells- migrate neurons from inner to outer surface

Front 86

what does the notochord release to induce overlying neuroepithelial cells to acquire properties of floor plate?

Back 86

sonic hedgehog (shh)

Front 87

how does shh work? what does it cause cells to do?

Back 87

represses Pax genes and causes neuroectodermal cells to assume ventral fate. cells then produce their own shh
-sets up floor plate

Front 88

what induces epidermal ectoderm cells to adopt dorsal fate? what plate is this at?

Back 88

BMP, to adopt dorsal fate at roof plate

Front 89

explain how gradients help to set up the plates in neural tube

Back 89

gradients of shh and BMPs that set up floor, basal, alar and roof plates
-shh at floor plate, BMPs at roof plate and concentrations dec as reach center

Front 90

what are some inductive signals for forebrain?
hindbrain?

Back 90

-forebrain- noggin, chordin and follistatin
-hindbrain- fibroblast growth factor and retinoic acid

Front 91

define rhombomeres; what genes control it?

Back 91

regularly spaced swelling of the developing hindbrain which contains sensory and motor neurons that develop in to cranial nerves
-Hox genes control by regulating transcription factors and by retinoic acid secreted by adjacent mesodermal cells

Front 92

what do cranial neural crest cells form?

Back 92

-connective tissue and skeletal contributions to face
-schwann cells
-ciliary and cranial sensory ganglia

Front 93

what do vagal neural crest cells form?

Back 93

-enteric (gut) nervous system

Front 94

what do trunk neural crest cells form?

Back 94

-melanocytes
-sensory and sympathetic ganglia
-adrenomedullary cells

Front 95

what do lumbosacral neural crest cells form?

Back 95

-enteric (gut) nervous system

Front 96

what signaling molecules differentially expression in forebrain region affect craniocaudal patterning?

Back 96

Wnt-1, shh, FGF-8

Front 97

after teh anterior neuropore closes, the rostral portion of neural tube subdivides in to what 3 vesicles?

Back 97

-prosencephalon (forebrain)
-mesencephalon (midbrain)
-rhombencephalon (hindbrain)

Front 98

what occurs in the middle region of the neural tube in development?

Back 98

does not further divide and becomes midbrain?

Front 99

what does the lower region of the neural tube develop in to?

Back 99

-rhombencephalon elongates to form metencephalon (pons and cerebellum) and myelencephalon (medulla oblongata)

Front 100

what structures compose the embryonic brain stem?

Back 100

diencephalon, mesencephalon and rhombencephalon

Front 101

describe the midbrain flexure

Back 101

anterior bend creates c-shape so proencephalon and rhombencephalon are almost parallel

Front 102

describe cervical flexure

Back 102

anterior bend where rhombencephalon meets spinal cord

Front 103

describe the pontine flexure

Back 103

posterior bend (concave dorsally) at level of pons

Front 104

what causes major shape change from spinal cord?

Back 104

thinning of roof plate over what is now the fourth ventricle

Front 105

what cranial nerve is associated with pharyngeal arch 1?
is it sensory, motor or both?

Back 105

trigeminal 5- both

Front 106

what cranial nerve is associated with pharyngeal arch 2?
is it sensory, motor or both?

Back 106

facial 7- motor

Front 107

what cranial nerve is associated with pharyngeal arch 3?
is it sensory, motor or both?

Back 107

glossopharyngeal 9- both

Front 108

what cranial nerve is associated with pharyngeal arch 4?
is it sensory, motor or both?

Back 108

vagus 10- both and autonomic

Front 109

what neural tube defect involves meninges or spinal cord protrusion through defect in skin and bone in lower back?
what are 3 different types?

Back 109

spina bifida
-occulta- no clinical sign
-meningocele- no nerves in space
-myelomeninocele- nerves in space

Front 110

what neural tube defect involves meninges and sometimes brain are herniated through a midline defect in skull and scalp?

Back 110

encephalocele

Front 111

what neural tube defect involves brain failing to form? how does infant survive (note- not compatible with life)?

Back 111

anencephaly, infant often survives because of intact brainstem function

Front 112

what disorder is characterized by lack of corpus callosum, chorioretinal lacunae and infantile spasms?

Back 112

acardi syndrome