Embryo & Genetics Flashcards
peanut esr
small lower
jaw
fish mouth
branchial arch disorder
CHL
treacher collins
small lower jaw
tongue further back
cleft palate
CHL
branchial arch syndrome
sticklers
underdevelopment of middle of the face & small lower jaw
near sightedness
CHL
joint problems (arthritis)
branchial arc syndrome
Pierre robbins
trigeminal nerve
tensor tympani
malleus & incus
all form from this arch
1st branchial arch (mandibular)
facial n
stapedius muscle
stapes
all form from this arch
2nd branchial arch (hyoid)
germ cells develop
pre embryonic
all organs develop from germ layers
embryonic
maturing of the organs
fetal
1/2nd arches invaginate at week 6, creates canal and it develops until week 26
EAC
(week 8-21) tubotympanic recess from 1st pouch, the ossicles develop outside of it and then month 8, they get sucked into the cavity
middle ear
3 hillocks between ½ arches, week 5 they appear, week 7 they fuse, week 30 complete formation (1st cleft has anterior half of it, 2nd cleft has posterior half of it)
pinna
22 days gestation, ectodermal placode thickens and invaginates to form otic pit, located dorsal to 2nd arch at day 26, then pit splits into ventral and dorsal part at day 28
inner ear
week 6, saccule pole extends. Week 8, it has done 2.5 turns, done developing by month 5
cochlea
week 6 SCC’s are flat pockets as extension of the utricle, week 9 mesenchyme hardens to form cartilage around the system (later turns to bone)
vestibular sytem
what does the cochlea develop from
sacculewhat d
what does the vestibular system develop from
utricle
centrioles go to poles
prephase
chromies line in the center
metaphase
chromies break at centromeres,
anaphase
new nuclear membrane forms at poles
telophase
replaces dead cells, somatic cells, ends with 2 identical daughter cells with a diploid set of 46 chromosomes, ensures identical daughter cells, 1 division cycle
mitosis
produces gametes, germ cells, ends with 4 different daughter cells with a haploid set of 23 chromosomes, ensures variation of daughter cells, 2 division cycles
meiosis
Sugar + Base + Phosphate
nucleotide
how do the bases pair
AT
GC
UAA, UAG,UGA
3 stop codons
AUG (methionine)
start codon
Double strand, has thymine, one less oxygen (deoxy), maintains proteins (encodes info)
dna
Single strand, has uracil, enough oxygen (ribose), carries protein (decoding info)
rna
DNA to RNA (in nucleus
transcription
mRNA to Protein (in cytoplasm)
translation
An environmentally caused trait that mimics a genetically determined trait
phenocopy
Thalidomide exposure is an example
phenocopy
The diverse effects of one gene or gene pair on several organ systems and functions resulting in multiple phenotypic effects in the body
Marfan’s
pleitropy
Only one chromosome of the chromosome pair is present rather than the usual two
Males are this because they have XY
hemizygous
causes 50-80% of all AR genetic HL
connexin
Increased K+ transport in the endolymph or increased endolymph production
Meniere’s disease
endolymphatic hydrops
Decreased K+ transport in the endolymph or decreased endolymph production
Connexin 26 HL
endolymphatic xerosis
hexagonal array of proteins in membrane of each cell that line up to the corresponding connexin proteins of the adjacent cell
connexin
35delG
connexin
Prior to or at conception, a pair of 21 chromosomes in either the sperm or the egg fails to separate (nondisjunction)
As the embryo develops, the extra chromosome is replicated in every cell of the body and accounts for an extra chromosome 21
the failure of the chromosomes to separate, which produces daughter cells with abnormal numbers of chromosomes
nondysjunction
Centromeres break and the long arms fuse → short arms fuse to form a new chromosome → new small chromosomes go away after few cell cycles → end result has new balanced chromosome with all the genetic information needed
robertsonian translocation
Occurs in nondisjunction of chromosome 21 takes place in one but NOT ALL of the initial cell divisions after fertilization
Some cells contain 46 chromosomes and others contain 47, which contain an extra chromosome 21
mosaicism