embryonic development Flashcards
1
Q
gametogenesis
A
- divide a haploid cell to divide our chromosomes
- process of halving DNA material
- turns a diploid cell into a haploid cell
2
Q
gametogenesis
A
- divide a haploid cell to divide our chromosomes
- process of halving DNA material
- turns a diploid cell into a haploid cell
3
Q
spermatogenesis
A
- sperm haploid
- call these gametes
- from 46XY to 23Y or 23X
4
Q
oogenesis
A
- ova/egg haploid
- call these female gametes
- from 46XX to 23X
5
Q
at the moment of conception =
A
fertilization –> zygote
- sperm has to get through zona pellucida
- ovum fertilized by spermatozoa and the nuclei of each gamete fuse - haploid gametes become diploid cells
- sex is already determined
6
Q
zygote
A
the first cell body
- will undergo repeated divisions and specializations of cell tissue (morphogenesis)
- point of fertilization through the first 7 days
7
Q
morphogenesis
A
- rapid proliferation and differentiation of diploid cells (mitosis)
- divide, specialize and migrate to their location
- occurs immediately and rapidly
- 1 week to morph the zygote into a blastocyst
8
Q
morphogenesis for the nervous system
A
- neuronal differentiation and migration
- axons need to sprout, grow and migrate
- synaptic circuits need to form
- dendritic connections need to solidify
9
Q
cell differentiation
A
- proteins influence genetic coding
- cells begin to specialize
- given coded differentiation
- 3 basic cell types = ectoderm, mesoderm, endoderm
10
Q
stem cells
A
undifferentiated; capable of differentiating and dividing
11
Q
cell migration
A
- proteins influence genetic coding
- cells begin to migrate given positional directives
- cells migrate to various areas
- cells cluster, thicken an area
- neuroblasts also migrate, to “lead” neural cells
- migration to the cerebral hemispheres is the longest and most demanding trip
12
Q
week 1
A
- zygote
- we said that morphogenesis has 1 week to transform a fertilized ovum into a zygote
- zygote= diploid cell.. the 1st cell of the body
- zygote has one week to do these jobs and become a blastocyst
13
Q
week 2
A
blastocyst
- travel down fallopian tube and implant on uterine wall
- morphogenesis has produced: inner cell mass for the embryo, inner fluid filled cavity, outer cell layer for the placenta, outer membrane (zone pellucida)
14
Q
week 2
A
blastocyst
- travel down fallopian tube and implant on uterine wall
- morphogenesis has produced: inner cell mass for the embryo, inner fluid filled cavity, outer cell layer for the placenta, outer membrane (zone pellucida)
15
Q
week 3
A
embryo = inner cell mass from our blastocyst
16
Q
embryo jobs
A
- flatten and fold
- fold over on itself
- form a disc
- form a primitive streak
- form a neural grove
- cells migrate/line up and specialize
17
Q
3 layers of the embryo
A
- ectoderm
- mesoderm
- endoderm
- all three form a notochord
18
Q
ectoderm
A
skin and nervous system
19
Q
mesoderm
A
muscle, cartilage, bone, blood vessels
20
Q
endoderm
A
digestive, respiratory linings
21
Q
ectoderm jobs
A
neural plate, neural grove, fold groove, makes a tube, close the tube
-if the tube doesn’t close, they can’t divide or form brain
22
Q
week 4 closed tube
A
closed tube has jobs
- differentiate and migrate
- produce ventricles and SCF
- begin to form SC
23
Q
3 brain vesicles
A
- prosencephalon = gives rise to cerebrum, lateral ventricles, thalamus, hypothalamus
- mesencephalon = rise to midbrain
- rhombencephalon= pons and medulla, cerebellum
24
Q
week 4 neural crest
A
- forms the SC
- meninges, grey matter (alar plate=sensory and basal plate= motor), sympathetic and parasympathetic ganglia, dorsal root ganglia, many CN ganglia
25
alar plate
sensory - dorsal
26
basal plate
motor - ventral
27
week 6
pharyngeal arches develop
28
pharyngeal arches
- 6
- develop at cranial end
- 5 do things we care about
- contains muscles and cartilage
- they need to meet at midline
- they becomes gills in fish
- in humans, form soft palate, mandible, facial musculatures, important arteries, CN input for voicing and mastication
29
1st arch
mandibular arch
- trigeminal nerve
- artery= external carotid artery
- muscles: for mastication, palatal musculature, mylohyoid, anterior belly dig
tissue: tympanic membrane
- bone: manidible, maxillae, malleus
30
2nd arch
nerve: CN VII facial
muscles: all the muscles we need for facial expressions; stylohyoid, posterior bell digastric, stapedius muscles, palatine tonsils
- bone: stapes, uper hyoid
31
3rd arch
nerve: CN IX glossopharyngeal
artery: common carotid and internal carotid
muscles: pharyngeal muscles
bone: hyoid bone (lower), common carotid, internal carotid
32
4th arch
nerve: CN X vagus - superior
artery: aortic arch, subclavians
muscles: palatal muscles, cricothyroid, thyroid and epiglottic cartilage
33
6th arch
nerve: CN X vagus recurrent
artery: pulmonary arteries
muscles: intrinsic muscles of the larynx
34
6th arch
nerve: CN X vagus recurrent
artery: pulmonary arteries
muscles: intrinsic muscles of the larynx
35
week 6 prosencephalon
cerebral hemispheres, lateral ventricles, 3rd ventricle
| diencephalon (thalamus, hypothalamus, epithalamus, 3rd ventricle, choroid plexus
36
week 6 mesencephalon
midbrain (brainstem)
37
week 6 rhombencephalon
metencephalon (pons, part of the 4th ventricle, cerebellum, cerebellar penduncles)
-myelencephalon (medulla, 4th ventricle, choroid plexus)
38
week 9-10
SC further develops
| **study slide 28
39
weeks 13-16
telencephalon takes off (cortex, BG, olfactory)
olfactory lobes, BG, and cerebral hemispheres engage rapidly
-neuroblasts begin migrating in an inside-out pattern
40
weeks 15-16
dorsal and ventral roots of spinal nerves meet; form full-fledged spinal nerves
-SC is about same length as vertebral column
41
week 20
convolutions of cerebral hemispheres begin to appear
42
week 24
gyri and sulci begin to appear
| lateral sulcus-first to appear
43
week 25+
cortex begins to stratify into layers (not complete until middle childhood)
44
study disorders
starting on slide 39
