introduction to Embryology Flashcards
what is the meaning of Logia
Study
meaning of embryon
unbron or embryo
embrology
study of the unborn
other name of embryology
organogenesis
meaning of organo
organs
meaning of genan
acquire or formulate
meaning of osis
state or status or process
this is the period between meiosis 1 and meiosis 2
interkinesis
other name of Interphase type II
Interkinesis
No growth, no DNA replication and no time to cast its
function, just pure rest after meiosis I and before meiosis
II.
Interkinesis
means thread
Mitos
means state or status or process
Osis
the process involving cytoplasm
Cytokinesis
separation of cytoplasm
cytokinesis
Daughter cells receive equal
amounts of cytoplasmic
volume
MITOSIS
After meiosis I and meiosis
II, one will receive much of
the cytoplasm and the other
one will receive hardly any.
MEIOSIS
Complete separation but
unequal distribution
OOGENESIS
Equal distribution but
incomplete separation
SPERMATOGENESIS
each daughter cell will receive equal amounts of organelles
true
what are necessary for the transformation of a circle looking cell in to sperm with head neck and tail
organelles
means movement
kinesis
means walneut
karyon
Prophase
metaphase
anaphase
elophase are under this
Karyokinesis
Maturation of gametes before fertilization
for sperm and egg cell
MEIOSIS
means a state, status, a condition or a process
“Meioun”
Introductory process prior zygotic, pre - embryonic and
embryonic period
FERTILIZATION
Periods of human embryology
Zygotic period Embryonic Fetal Neonatal Prenatal
this period of human embryo
- first month after birth
Neonatal period
this period of human embryo
- 9th week until 9th month in the stomach
Fetal period
this period of human embryo
- first day or first 24hrs after fertilization
Zygotic period
this period of human embryo
- first eight weeks of life after fertilization
- 3-8 weeks
- mitosis and meosis
embryonic period
organogenesis
organs start to form
2 types of cell division
meosis
mitosis
this period of human embryo
- 22nd week to 7 days after birth
Prenatal period
This gene forms the Heart
Homeobox protein NKX 2.5
this gene forms the kidney
WT1/Wilms tumor 1
this gene forms the ventral midline structure
sonic hedgehog
this gene regulates mitosis
CDK1/CDC2, pre-MPF (Pre-maturation promoting factor gene)
Phases of Cell cycle
Interphase
interphase is divided into 3 phases
G1
S
G2
this interphase phase
- gap between telophase and S phase
G1
this interphase phase
- gap between S phase and Prophase
G2
does karyokinessis and cytokinesis thru 4 phases
mitosis
how many hpurs does the cell spending interphase
24hrs
90-96% time accounted for
Gap 0
the cell has no intention to develop
this is an interphase phase where
- where cell grows and fuctions properly
Gap 1
involved in locomotion and movement
Myocyte
liver cell
hepatocyte
this changes the morphology of chromosomes from tightly coiled to straight
for dna dupli
Lysine rich Histones LH
what type of replication occurs in the S phase
Semi consevative type repli
genetic mutataion can occur in s phase
what kind of repli should happen
Semi conservatice repli
Makes dna strands linear
Histones
makes dna strands coiled
crumpled and condensed
Protamine
this is an interphase phase where
- high amounts of protein
- cells doubles in size
- more organelles are produced
- cytoplasm increases
Gap 2
equational division
Mitosis
mother cell gives rise to 2 new cells
each receive an equal amount of chromosomal Complement
Mitosis
daughter cells receive half of the chromosomal complement
- reductional division
meiosis
thin original copies and replicates of dna
- the cell thickens
- chromosomes begin to coil and contract
Prophase
why is condensation imprtant in prophase
avoids extra transcription
translation
replication
the 2 pairs of centromeres
inner pair
outer pair
this pair of centromere
- for mitotic spindles
- replicated copy meets original copy
outer pair
pair of centromere
- links two chromatids
inner pair
true or false
the chromatids are linked to their HETEROZYGOUS pairs to link iup to form chromosomes
False
homozygous
this is a phase after prophase but before meta phase
- x like structure
- nuclear membrane starts to disappear
- mitotic spindle
- moves outward/ polar opposite
Prometaphase
this phase
- chromosomes arranged equatorial plane
- kinetochore will be attached to distal ends of matrix spindle
Metaphase
imagine line also called equatorial plane
metaphase plate
3 phase of anaphase
early
mid
late
This anaphase
- mitotic spindles shorten
- chromatids are detached from their sister chromatid due to pulling effect
early anaphase
this anaphase
- chromatids are fully seprated and start to move away
mid anaphase
this anaphase
- chromatids have fully migrated to the spindle bundles
- tids have arrived to the centrioles
late anaphase
this phase where
- prior to S phase
- tids uncoil
- simultaneous is cytokinesis
- eough cytoplasm is received
telophase
this cell division generates the gametes or germ cells
- has to sets of cells division
- 4 daughter cells
Meiosis
true or false
after days meiosis will produce 4 new daughter cells having half the genetic info
true
how many daughter cells does mitosis have
2
memorize page 4
page 4
prolonged prophase I
- with chiasma formation
- detachment leading to pulling of double structure
Prophase I
phases of prophase I
Leptotene Zygotene Pachytene Diplotene Diakinesis
Phase of Prophase I
- leptos mean thin
- pairing starts to begin between homozygous parts
- this is the compared to Gap 2 stage
- help of centromere
Leptotene
Phase of Prophase I
- zygos means pairs
- pairing process via synapsis
- with the help of central synaptonemal complex
Zygotene
Phase of Prophase I
- paired homologous chromosomes become short and thick
- coiling condensation and contraction
- thickest configuration
- chiasma forms
- crossing over
- Pachus means thick
Pachytene
Phase of Prophase I
- paird hybrid chromosome will start to appear and form
- egg cell in form of oocyte and first arrest state
Diplotene
Phase of Prophase I
- moving along
- mitosis prometaphse stage
- prepares for dividing
- mitotic spindle and nuclear membrane start to disappear
- MeIG gene 1 activates
- MPF gene
Diakinesis
this phase in Meiosis
- paird chromosomes are placed in the central stage by the mitotic spindle
- central stage is called metaphase plate
- all 23 pairs in the central stage
Metaphase I
this phase in Meiosis
- both meiosis and mitosis have early, mid, late stages
- homologous hybrid chromosomes are separated
- homozygous seperation in mitotic
Anaphase I
this phase in Meiosis
- goes straight to the egg or sperm cell
- simultaneous is cytokinesis
Telophase I
has unequal distributon of cytoplasmic volum
but complete seperatioon
- one daughter cell receives, all others hardly
Egg cell cytokinesis
either meiosis I or meiosis II, there is equal
distribution of cytoplasmic volume but incomplete
separation.
sperm cell cytokinesis
this bridges ensure equal distribution of organelles in daughter cells
cytoplasmic bridges metaphase I
The circle looking cell turns into a cell with head, neck
and tail. The complete set of organelles participates in this
transformation.
Spermiogenesis
Parts of the Sperm Cell
- Acrosomal cap
golgi appa
complexes
Parts of the Sperm Cell
- head
nucleus
Parts of the Sperm Cell
- spirals in the middle
mitochondria
Parts of the Sperm Cell
- flagellum
centrioles
microtubules
meoitic spindles
a result of alterations and problems during the
cytokinetic process of either Oogenesis or spermatogenesis
MORPHOLOGICAL DEFECTS
unequal
distribution of
organelles
diagnosed as
Teratozoospermia
permit multiple
fertilization
processes.
multiple gestation like twin
or triplet gestation.
after meiosis I occurs
this follows
Interphase II or interkinesis
what is difference of prophase I and II
prophase II is not prolonged
no leptotene et al.
● Process of generating a mature female cell
- at the 7th week
OOGENESIS
meaning of OO
Egg
ovum
female seed
meaning of genan
create
formulate
meaning of osis
process
Two sets of process of oogenesis
- OOCYTOGENESIS
- OOTIDOGENESIS
this is the process of generating primary oocytes
Oocytogenesis
process of generating ootids (most mature type of oocyte)
- has 2 indirect processes
Ootidogenesis
two indirect process of ootidogenesis
- fertilization
- ovulation (puberty 1st stage)
primary oocytes originate from
ooginium
Genocytes
primordial germ cells
Types of Genocytes
44 + XY → spermatogonium
44 + XX → oogonium
when does genocytes start to appear
3rd week of AOG in yolk sac
main source of the embryo’s nutrition,
yolk sac
- first respiratory unit of the embryo
- Conduit to transport all of the embryo’s waste from the
embryo’s body to the placenta
Allantois
memorize mnemoic page 8
page 8
when is the earliest a cycle of oogenesis is completed
7th week of AOG
7 million oocytes will be formed by 5th month
5th month of AOG
master gene for caspase synthesis
Casp3
– enzyme that promotes apoptosis
Caspase
- cells start surrounding linear epithelial arrangement
- makes connecting bridges
- follicular cells will start to produce cAMp and purines
First Cell Arrest
sulfated glycoproteins of the follicular cells and primary oocyte - Protection - Glycoproteins act as sperm receptors that induce acrosomal reaction
Zona pellucida
Surrounding cells
Follicular cells
Primary Oocyte + Follicular Cells
→ Primordial Follicle
All surviving primary oocytes undergo prolonged Meiosis I
(Diplonema/ Diplotene stage).
- a
until
until what age does the first stage is active
Puberty to prolong the eggs till age 44
Removes the cells from the 1st arrest stage
- influence hormones
- ovulating
Ovulation
15-20 primary oocytes will lift from their arrest stage
- forming 2nd oocytes
- cytokinesis I
12hrs prior to ovulation
- receives most of the cytoplasm
o Will undergo division, producing one oocyte and
one polar body
- Secondary oocyte
receives practically no cytoplasm
o Will undergo division, producing more polar bodies
that will eventually degenerate
o Reason why there is a decrease in the number of
egg cells during development
first polar body
second stage of
arrest
interkinesis
Secondary oocytes will undergo their second stage of
arrest (called
3 HOURS PRIOR TO OVULATION
-An egg cell is released from the ovary and into the
fallopian tube.
- eggs will wait 24-48 hrs to be fertilized
- no fertilization = arrest state
- fertilized = metaphase of meiosis
OVULATION
Removes the cells from the 2nd arrest stage
- indirect process that will finish off oogenesis
fertilization
- this is 28 days
- ovulation on 14th day
- LH peaks 14th day
- estrogen decreases
- progesterone increases
Menstrual Cycle
Phases of Mens
- Proliferative phase
- Secretory phase
- Menstrual phase
this menstrual phase
- occus when no fertilization happens
- shedding of endometrium
- blood escapes
Menstrual phase
this menstrual phase
- thickening of endometrium
- begins at end of mens phase
- influence of estrogen
Proliferative phase
this menstrual phase
- 2 or 3 days ofter ovulation
- progesterone
- maximum thicness endometrium
Secretory phase
Process of generating mature male seeds
SPERMATOGENESIS
Spermatos
Male seed
genan
generate
osis
process
originate from the epiblast and are formed in the epiblast
during the second week of gestation.
- 3rd week of AOG
Primordial germ cell
HNF3-b
(Hepatocyte Nuclear Transcription Factor)
master gene in differentiation of epiblast in 3 layers:
Ectoderm, Mesoderm, Endoderm (these
HNF3-b
● Mitotic division (PMAT) and replication of spermatogonia
diploid 2n
SPERMATOCYTOGENESIS
“Nurse cells”, provide structural,
nutritional, and chemical support to dormant PGC until
puberty is reached at age 10
Sertoli Cells
three types of spermatogonia
Type A Dark
Type A Pale
Type B Dark
Type of spermato gonia
- last mitosis
- last cycle of mitosis
-
type b dark
Type of spermato gonia
- inactive mitosis
- will give type Ad spermatogonia
Type A Dark
Type of spermato gonia
- active mitosis
- active in dividing
- cells turn into type B
Type A Pale
Ad spermatogonia
turns into Type A pale
- activated by Meig 1
PRIMARY SPERMATOCYTES (parent cell) → SECONDARY SPERMATOCYTE → SPERMATIDS
SPERMATIDOGENESIS
SPERMATIDOGENESIS
-the primary spermatocyte enters the 1st & last arrest
state during the prolonged Prophase I stage, the dictyate
stage (stays in arrest for 22 days)
Meiosis I
Equal distribution of cytoplasmic volume, but incomplete
division/separation
Cytokinesis
1-10 micrometer in diameter, essential for maturing
sperm cell
- point of trnasfer passage for spem
Cytoplasmic bridge
Series of changes resulting in the transformation of
SPERMATIDS into SPERMATOZOA
SPERMIOGENESIS
3 types of barriers in spermiogenesis
a. Granulosa cells/Corona radiata
b. Zona pellucida (egg shell of egg cell)
c. Plasma membrane of secondary oocyte arrested in
metaphase of Meiosis 2
where is the flagellum derived from
Condensed centriole
master gene for spematogensis
PAx 5
master gene for spermiogenesis
Meig-1
“Letting go” process
SPERMIATION
Hastens the motility of the maturing sperm cells
- Leads spermatozoa to be transported from the
seminiferous tubules, rete testis and to the head of the
epididymis
Seminiferous tubular fluid
Marks the start of stage 1 (of direct processes)
● begins at age 10 after birth,
Puberty
deposit of sperm cells from the male external genitalia to
female external genitalia
SPERM TRANSPORT
- sperm into female genitilia
- from vas deferens to ejac duck to penile shaft until it is deposited in the vagina
Ejaculation
how many secs from vaginal vault to inner
15 secs
how many days does the sperm travel in the cervic
3 days
how many hours in the uterus
7 hrs
- happens in the fallopian tube
- ## period of conditioning of the spermatozoa
CAPACIATION
to expose the essential enzymes needed for acrosomal cap penetration
the denudation of
proteins
colony of cells dragged by secondary
oocyte during ovulation
Corona radiata
sulfated egg shell of the egg cell
Zona pellucida
- considered
same-species specific membrane (where one of the 13
enzyme can offer help)
Plasma membrane of secondary oocyte
pronucleus of spermatozoa meets the pronucleus
of the rested secondary oocyte after penetrating the barrier
Fertilization
