ART & INFERTILITY Flashcards
(165 cards)
1
Q
What Is The Pregnancy Rate After COH/IUI For Women With An FSH >10IU/L
- 0%
- 2%
- 4%
- 6%
- 8%
- 10%
A
1.
2
Q
Which Blood Type has the Highest Chance of success
- A
- B
- AB
- O
A
2.
3
Q
BCL2 gene defest
A
lack of sperm BCL2 lead to aportive appoptosis
4
Q
cryptochidism
A
undescended testis
5
Q
Caesarean Section and subsequent Fertility
A
there is NO association
6
Q
A Mother’s diet before she conceives has a permanent effect on her offspring’s genetics as shown by the increased presence of epigenetic markers during the year
A
true
7
Q
Abnormal PLCZ1 Function Is Associated With Reduced, Poor Or Failed Fertilization In Normospermic Semen Profiles.
A
true
8
Q
Abnormal PLCZ1 Function Are Associated With…
A
Reduced robust [Ca2+]i oscillations upon injection into eggs
Oocyte activation
PLCZ1 function could be the underlying cause of failed fertilization
PLCZ1 function should be assessed in cycles with low or failed fertilization.
9
Q
Delaying the oocyte maturation trigger in IVF/ICSI Increases the Number of Mature Oocytes
A
true
10
Q
Delaying the Oocyte Maturation Trigger In IVF/ICSI may be of benefit in:
A
Women with a low progesterone
11
Q
In patient with low basal progesterone, delaying HCG by one day increased the number of MII by….
A
2.4
12
Q
The Percentage of normal semen profiles is lower in HBsAg-seropositive male partners
A
true
13
Q
The Percentage of Good Quality Embryos was Lower in Female Partners being HBsAg-Seropositive
A
true
14
Q
The fertilization rates in groups with male or female partners being HBsAg-seropositive was significantly lower
A
true
but no different in Pregnancy Rates in male or female HBsAg seropositive
15
Q
Live Birth Rates are Compromised when the Serum Progesterone at HCG was:
- =<0.5 ng/ml
- 0.50–0.75 ng/ml
- 0.75–1.00 ng/ml
- 1.00–1.25 ng/ml
- 1.25–1.50 ng/ml
- >1.50 ng/ml
A
1, 6
16
Q
Uterine Peristalsis before embryo transfer affects the chance of clinical pregnancy in:
- Fresh Embryo Transfers
- Unstimulated Frozen Embryo Transfers
- Stimulated Frozen Embryo Transfers
A
all correct
Uterine peristalsis:
wavy movements(contractions)of sub endometrial myometrium or endometrium.
17
Q
which stimulation regimen delivers a better outcome (babies/cycle) for poor responders (<4 eggs in previous cycle).
- Long down regulation agonist stimulation
- Antagonist stimulation
A
1.
reference????
18
Q
What proportion of cases expected to achieve fertilization in a second ICSI attempt after total failed fertilization (TFF)
- 30%
- 40%
- 50%
- 60%
- 70%
- 80%
A
4.
reference????
19
Q
In a recent study a second ICSI attempt after total failed fertilization (TFF), what was the most significant difference associated with success?
- Recover more oocytes
- Delay insemination
- Delay hCG Trigger
- Employ more than one scientist for the injection.
- nothing, just repeat the treatment plan a second time.
A
1.
20
Q
Donors younger than 20 years of age have a lower live birth rate than donors aged 20-40 years of age.
A
true but not significant low
21
Q
Which markers predict ovarian response in normal responders
A
- AMH
- Antral Follicle Count
- Basal FSH
- Age
22
Q
The use of a portable CO2 incubator to transport oocytes (donor) or embryos does not appear to be detrimental
A
true
23
Q
Letrozole is superior to Clomiphene in ovulation rates and pregnancy for women with Polycystic Ovary Syndrome PCO
A
TRUE
24
Q
In culture mediaThe Pyruvate/Lactate Ratio has significant impact on the offspring birth weight
A
true
25
KIsspeptin-54 can induce normal ovulation and pregnancy in antagonist managed COH IVF Cycles
true
26
A Human Oocyte-Derived Sperm Chemoattractant is a Hydrophilic Molecule Associated with a Carrier Protein
False
## Footnote
Oocyte-Derived Sperm Chemoattractant ►Hydrophobic
molecule
27
The proportion of men with normal semen profiles after cancer treatment was:
1. 75%
2. 48%
3. 39%
4. 25%
5. 9%
2
28
..............gene is Critical for directing human stem cells to become PGCs
**SOX17**
29
In women with normal ovaries who have regular menstrual cycles, approximately how many days does it take for a primary follicle to develop to a mature preovulatory follicle?
3 months
primary follicle-MII
30
The testis is enclosed in a fibrous outer capsule called the......
Tunica albuginea
31
The Tunica Albuginea can contract to help move sperm from the testis to the epididymis
true
32
the main role of the Leydig cells is to produce....
**Androgens**
33
the main function of the seminiferous tubules is to make spermatozoa
true
34
The testis is relatively Avascular
true
Avascular: (lack of blood vessels)
35
During Pregnancy, the Uterus is termed.....
Gravid
36
A Multiple Pregnancy is called..............
a Multiparous Pregnancy
37
During foetal pregnancy, the primoidal germ cells PGCs are first seem in..........
**yolk sac**
38
The period of rapid cell division of the primordial germ cells stops prior to............
parturition (labor)
39
The maximium number of oogonia are fixed prior to birth
true
40
The Primordial Germ Cells That Undergo a Period of Cell Division are Called....
**Oogonia**
Remember :
Primordial Germ Cells That Undergo a Period of Cell Division ►**Oogonia**
Oogonia entering the first meiotic division are called **primary oocytes.**
41
The goal of ovarian stimulation is to induce ongoing development of........
**multiple dominant follicles**
42
**Clomiphene** is used to induce mono-ovulation in anovulatory women
true
43
**Clomiphene Citrate** Is an Anti-Oestrogen
TRUE
44
Hot Flushes are a side effect of using Clomiphene Citrate
true
45
used to induce ovulation in PCO women....
1. Clomiphene Citrate
2. Letrozole
3. Metformin
3.
## Footnote
Letrozole NOT used in ovulation for PCO
clomiphene and metformin used together
46
Earle`S Balanced Salt Solution was used early in Embryo Culture
true
47
Early Cleavage is controlled by....
1. paternal RNA
2. maternal RNA
3. Embryonic genome
2.
Remember:
Early Cleavage is controlled by **maternal RNA**
Blastocyst Growth is controlled by the Embryo **Genomic Regulation**.
48
Pyruvate is Preferred in the ..........
2pn and early cleavage
49
The Early Embryo is Sensitive to Glucose Concentrations
true
50
The Concentration of Glucose in Tubal Fluid is.....
**~0.5mM**
51
Low semen Volume may Indicate.........
Epididymal Obstruction
52
Reddish brown colour of semen ejaculate may indicate...
Erythrocytes or inflammation
53
A Normal Sperm is .............in Length
4.0 - 5.5 Um
54
The ability of an embryo to regulate its metabolism is directly related to its ability to implant and form a viable pregnancy
true
55
A rapid rise in ATPase activity occurs at:
1. 4-8 cell stage
2. early compaction
3. morula stage
4. early blastocyst stage
5. Expanding stage
6. Fully expanded stage
7. Hatching
5.
56
The main consumers of ATP in the embryo are:
1. Na+, K+ ATP sodium pump
2. Protein synthesis
3. DNA Replication
4. Cell membrane synthesis
1.
57
The Na+, K+ ATPase Pump Exchanges
1. One Na+ out of and one K+ in to a cell
2. Two Na+ out of and one K+ in to a cell
3. Thee Na+ out of and one K+ in to a cell
4. Three Na+ out of and two K+ in to a cell
5. Four Na+ out of and two K+ in to a cell
6. Five Na+ out of and four K+ in to a cell
4,
Na+, K+ ATPase Pump Exchanges ⇔
**3 Na+ (**«** out )⇔ 2 K+ (in») **
58
The Na+/K+ ATPase is Located...............
**Basolateral region of the trophectoderm**
59
The human Na+/K+ ATPase Pump is present in the morula but upregulated during expansion by:
1. 2.3 fold
2. 3.3-fold
3. 4.3 fold
4. 5.3 fold
2.
60
During blastocoel expansion, the Na+/K+ ATPase Pump Consumes
1. 20% of ATP
2. 30% of ATP
3. 40% of ATP
4. 50% of ATP
5. 60% of ATP
5.
61
Fully Expanded Blastocyst, The Na+/K+ ATPase Pump, Activity
1. Continues at the same rate
2. Continues but at a significantly lower rate
3. Ceases
2.
After fully Expanded Blastocyst, The Na+/K+ ATPase Pump, Activity Continues but at a significantly lower rate.
Remember:
During Expansion, the blastocyst appears to consume the major proportion of generated ATP
62
What are the three main stages of gestational development?
**_Early development_**
*Embryonic period*
**_Fetal period_**
63
What 5 things comprise the period of early development?
Fertilization►, Implantation►, Formation of trilaminar embryo,► Placental formation, ►Deination of body axes
64
What is the approximate time period of Early Development?
0-2 weeks
65
How sensitive to teratogenesis is the zygote during Early Development?
**Not usually sensitive**
66
What is the approximate time period of the Embryonic Period?
3-8 weeks
67
How sensitive to teratogenesis is the Embryo?
**The embryonic period** is the period of greatest sensitivity throughout the pregnancy
68
What is the approximate time period of the Fetal Period?
**9-38 weeks**
69
How sensitive to teratogenesis (in general) is the Fetus?
Initially more sensitive
but
sensitivity decreases as the fetal period progresses
70
How sensitive to teratogenesis (in general) is the Fetus?
Initially more sensitive, but sensitivity decreases as the fetal period progresses
71
What is the general morphology of the embryo at the beginning of the embryonic period?
Flat disc, 2 cell layers thick
72
What 6 structures are still highly vulnerable to teratogenesis during the Fetal period?
Brain, Eyes, Ears, Palate, Teeth, External Genitalia
73
What structure designates the midline of the embryo during development?
Notochord
74
What is a somatotopy and why is it significant?
It is a "**body map"** - shows how gene expression differs by region
75
What are the products of one round of meiosis in males and in females?
**Males - 4 spermatids;**
**females - 1 ovum, 3 polar bodies**
(note: technically only 2 are formed, 3rd formed upon fertilization)
76
Where is the origin of the primordial germ cells, and where to they migrate?
Epiblast -\> Gut -\> Genital Ridge
77
What are the respective male and female gametic supportive cells?
Sertoli cells (male)
follicular cells (female)
78
\_\_\_\_\_\_\_ cells secrete _________ (hormone) which "stimulate" primordial germ cells at puberty in males
Leydig, testosterone
79
During which two cellular gametogenic stages does meiosis occur in males?
Primary spermatocyte ⇒ secondary spermatocytes
and
secondary spermatocyte ► spermatid
80
What is required for sperm to activate, and where does this occur?
Capacitation, which occurs in the female reproductive tract
81
Spermiogenesis (the conversion of spermatids into mature sperm) is characterized by:
**Nuclear condensation,**
**Loss of cytoplasm,**
**Formation of an acrosome,**
**Neck and tail formation**
82
By week ___ of female fetal development, a population of ______ enter the first meiotic phase and become dormant until puberty
By week \_**12\_\_** of female fetal development,
a population of **\_\_Oogonia** enter the first meiotic phase and become dormant until puberty
83
What comprises the primordial follicle?
Capsule of **squamous cells** and follicle
84
What comprises the **primary follicle**?
Capsule of **cuboidal cells** and follicle
85
What do **follicular cells** secrete to prevent any further progression of the cell cycle?
follicular cells secrete **OMI (Oocyte maturation inhibitor)**
to► prevent any further progression of the cell cycle.
86
Identify the types of follicles shown
Primordial, Primary, Graafian
87
Ovulation is preceded (just before day 14) by a sudden large spike in what two gonadotropins?
LH & FSH
88
What glycoprotein coat is secreted by the follicle cells and oocyte together?
Zona pellucida
89
What hormone secreted by what tissue prevents the degeneration of the corpus luteum?
**HCG** (Chorionic gonadotropin), Secreted by Syncytio-trophoblast until the formation of Placenta
90
**Prader-Willi syndrome**
is a syndrome characterized by hypotonia, and is thought to be caused by a microdeletion on paternal chromosome 15 ► result in ( **Paternal** imprinting defect)
91
**Angelman syndrome**
A syndrome characterized by:
lack of speech, weakness in all four extremities, and uncontrollable bouts of laughter, and is thought to be caused by≈
a microdeletion on **maternal** chromosome 15
Note:(if paternal chr 15 deletion ►Prader-Willi syndrome)
92
Turner syndrome
XO; Is syndrome characterized by short webbed neck, cubitus valgus, and lymphedema?
93
Klinefelter's syndrome
A Syndrome characterized male genetically by a 47, XXY genotype?
94
What is the process of a sperm fertilizing a secondary oocyte, starting with the first ovum barrier, ending with the final meiotic division?
Sperm penetrates corona radiate► Sperm binds to zona pellucida► Plasma membranes of sperm and oocyte fuse► Oocyte releases lysosomal enzymes, inducing the zona reaction (causes binding sites on the zona pellucida to change)► Both replicate their DNA► Final polar body released by meiotic division
95
What is the physical boundary for the secondary oocyte/zygote until blastocyst formation?
ZP
96
Most contraceptive pills are either \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_, or an analogue thereof.
P
97
**Stone baby**
A lithopedion or stone baby, is a rare phenomenon which occurs most commonly when a fetus dies during an abdominal pregnancy,
**Stone baby**: calcified embryo. Pelvic/abdominal CT scan most likely to reveal it
98
# Define placenta previa
Implantation occurs at the cervix
99
# Define placental accreta
Placenta penetrates too deeply (syncytiotrophoblast invasion)
100
# Define placental abruption
Separation of placenta from the endometrium
101
What are the two layers formed within the embryoblast, and their defining features?
**Epiblast**: outside layer, high columnar cells adjacent to amniotic cavity;
**Hypoblast:** inside layer, small cuboidal cells adjacent to blastocyst cavity
102
What are the two layers of the trophoblast, and their defining features?
Cytotrophoblast (maintains cellularity) and Syncytiotrophoblast.
(lose individual cellularity, becomes a multinucleated cell)
103
What 2 cavities are formed in the **second week** of development?
Amnion and yolk sac
104
What two layers does the extraembryonic mesoderm split into?
Somatopleure and Splanchnopleure
105
What layer within the embryoblast forms the amniotic cavity?
Epiblast
106
What is **polyhydramnios**, and what kind of developmental problems might it indicate?
Too much amniotic fluid \> 2**L**,
may indicate⇒ problem with **Gastrointestinal** *GI* **system**
107
What is oligohydramnios? What kind of developmental problems might it indicate? Result in?
Low volume of amniotic fluid \<0.5**L**. May indicate problem with urinary system. May result in poor limb development
108
What large cavity surrounds the embryoblast and fills the trophoblast?
Chorionic cavity
109
What structure is indicated in day 13
formation of Exraembryonic membranes
notice the formation of **Somatopleuric** layer and
**extraembryonic** mesoderm.
and **Splanchnopleuric layer** cover the Yolk sac
110
What is the function of the syncytiotrophoblast?
Invade endometrium,►Erode maternal tissue,► Secrete hCG
111
What is the name of the cavities that form in the syncytiotrophoblast? What are they there for?
**Trophoblastic lacunae**
which accept blood being "dumped" in from **maternal sinusoids**
112
What are primary villi?
Cellular columns originating from the embryo, penetrating into and **surrounded by the syncytium**
113
At what point do primary stem villi become secondary stem villi?
Day 16, when the **extraembryonic mesoderm** extends into them
114
At what point do secondary stem villi become tertiary stem villi?
End of **week 3**, when they have formed blood vessels that connect to forming fetal **blood vessels**
115
Which parent's genome contributes more to the formation of the trophoblast?
**paternal genomes (Father)**
116
**Genomic Imprinting**
Differential modification and/or expression of homologous alleles or chromosome regions depending upon the parent from whom it was derived
117
**Hydatidiform mole**
**Hydatidiform mole** is a rare complication of pregnancy characterized by the abnormal growth of trophoblasts (**paternal imprinting origin**)
**Caused by fertilization of an empty oocyte. Zygote begins to develop, but never forms embryoblast (just trophoblast)**
A patient presents with nausea and vaginal bleeding in her first trimester of pregnancy.
⇒Physical examination reveals a uterus that is enlarged for her gestational age►, and bloodwork shows► **abnormally high levels of hCG**.
118
What does the primitive pit indicate?
Midline of body Forms on cephalic end
119
What morphologically characterizes the prechordal/cloacal plate, and what do these sites indicate?
Ectoderm and endoderm in direct contact with each other, no mesoderm. These sites indicate the location of development of the mouth and the anus, respectively
120
What are the 4 important characteristics of the notochord for development?
Anatomic midline,
CNS development,
Vertebral column development
, Nucleus pulposis formation
121
What disorder causes an organ or organs to be formed outside the body? What development error causes this?
**Gastroschisis** - caused by anterior wall defect (failure to completely enclose splanchnic/somatic mesoderm)
122
# Define situs inversus
One or more organs on the opposite site of the body from "normal"
123
**Holoprosencephaly**
Holoprosencephaly (HPE) is the failure of the prosencephalon, or forebrain, to develop normally.► Failure in producing proper midline for facial structure.
(can be mild, moderate, or severe)
result from mutations of **sonic hedgehog (shh) gene**
124
In cases of holoprosencephaly, defects of facial structures are typically secondary to defects of the:
* A. Pharynx
* B. Oral cavity
* C. Forebrain
* D. Eyes
* E. Hindbrain
c.
125
Cleft lip results from lack of fusion of the:
A. Nasomedial and nasolateral processes
B. Nasomedial and maxillary processes
C. Nasolateral and maxillary processes
D. Nasolateral and mandibular processes
E. Nasomedial and mandibular processes
B.
## Footnote
NOTE:
The medial nasal process (nasomedial) on the inner side of each nasal pit merge into the intermaxillary segment and form the upper lip, crest, and tip of the nose. The medial nasal processes merge with the maxillary prominences. The lateral nasal process from each side merge to form the alae of the nose.
126
The facial nerve (cranial nerve VII) supplies muscles derived from which pharyngeal arch?
A. First
B. Second
C. Third
D. Fourth
E. Sixth
B.
127
. Meckel’s cartilage is a prominent structure in the early formation of the:
A. Upper jaw
B. Hard palate
C. Nasal septum
D. Soft palate
E. Lower jaw
E.
## Footnote
Meckel's cartilage is a piece of cartilage from which the mandibles (lower jaws)
128
A woman who averaged three mixed drinks a day during pregnancy gave birth to an infant who was mildly retarded and who had a small notch in an upturned upper lip and a reduced olfactory sensitivity. What is the basis for this constellation of defects?
These defects could be a manifestation of **fetal alcohol syndrome.**
They could represent a mild form of **holoprosencephaly**, which in this case would relate to defective formation of the **forebrain** (prosencephalon).
The defects in olfaction and in the structure of the upper lip could be secondary effects of a primary defect in early formation of the prosencephalon
129
What is sirenomelia, and what is it caused by?
Called "**mermaid syndrome"**, caudal dysgenesis - not enough mesoderm to make lower extremeties. Caused by **oligohydramnios**
**Sirenomelia**, which is also known as **mermaid syndrome,** is an extremely rare congenital developmental disorder characterized by anomalies of the lower spine and the lower limbs.
130
**Sacrococcygeal teratoma**
Sacrococcygeal teratoma (SCT) is a tumor that develops before birth and grows from a baby's coccyx — more commonly known as the tailbone. It is the most common tumor found in newborns, occurring in 1 out of every 35,000 to 40,000 live births.
131
What is the significance of the neural ectoderm?
Signaled by the notochord to become the neural plate; forms the CNS
132
When do the cranial and caudal neuropores close?
Cranial: day 24-25;
caudal: day 26-27
133
What 3 major derivatives form from neural crest cells?
**Parasympathetic ganglia of CN 3, 7, 9, 10**
**Sensory ganglia of CN 5, 7, 8, 9, 10**
**Autonomic and dorsal root ganglia**
134
Surface ectoderm will give rise to what 5 major structures?
EpidermisAnterior pituitaryTooth enamelInternal earPhakic lens
135
What are the 3 "rod and sheet-like" mesodermal derivates and what systems will they form?
**Paraxial mesoderm -**
**axial skeleton, skeletal muscle, part of the dermisInediate mesoderm -**
**urinary and part of genital systemLateral plate mesoderm -**
**gives rise to splanchnic and somatic mesoderm**
136
## Footnote
**Somites**
**Somites**
("Bricks" of mesoderm),
later form⇒ skeletal muscle
137
external genitalia can be distinguished as male or female at week?
week 9
138
primary ovarian follicles formed and testes descend during week ........?
Weeks 17-20
139
surfactant beginning to be secreted in the lungs?
Weeks 21-25
140
Lungs are capable of breathing CNS capable of controlling breathing and body temperature Hematopoeisis shifts to bone marrow at ......week
(week 28)
141
**"finishing period**
Weeks **35-38**; final preparations of tissues important to transition to the outside world
142
What are the major sites of embryonic hematopoeisis during what time periods?
Weeks 1-12: yolk sac
Weeks 12-30: liver
Weeks 12-24: spleen
Week 30: bone marrow
143
What embryonic layers must be penetrated in order to perform an amniocentesis?
Chorion (syncytiotrophoblast, cytotrophoblast, extraembryonic mesoderm) and amniotic sac
144
An amniocentesis is performed in the third trimester of pregnancy, revealing elevated levels of alpha fetoprotein. What disorder might be the cause? Why? What causes this disorder?
**Spina bifida** - incomplete posterior wall closure (neural tube defect) would result in leakage of alpha fetoprotein into the amnion
145
All but the first ___ somitomeres give rise to \_\_\_\_\_\_\_\_\_\_\_. Regardless of this, all somitomeres eventually give rise to _________ tissue.
All but the first **7** somitomeres give rise to **somites** Regardless of this,
all somitomeres eventually give rise to **muscle** tissue
146
Somites and somatomeres arise from what?
Paraxial mesoderm
147
What contributes to the development of the nucleus pulposus? The annulus fibrosus?
Notochord, Sclerotome
148
The muscle of the head arises from \_---------?
Somitomeres
149
The muscle of the torso and limbs arises from \_\_\_\_\_\_\_\_\_\_\_
Hypomeres (Somites)
150
The dermomyotome eventually splits into what two layers?
Dermotome and myotome
151
The cells of the myotome split into two parts. What parts are they and what is their relative positioning?
Dorsal epimere and ventral hypomere
152
What are the events that lead to differentiation of myotome into muscle fibers?
Myotome cells become myoblasts elongate, migrate, and fuse, forming myotubes Contractile filaments appear in cytoplasm--\>Muscle fiber
153
The epimere gives rise to what two things?
Dorsal ramii, deep back muscles
154
The **hypomere** gives rise to several various structures originating from a ventral or lateral region. What is the innervation of these structures?
**All innervated by ventral rami**
155
# Define myotome fusion and give an example
Muscles innervated by more than one spinal cord level - rectus abdominus
156
Define myotome splitting and give an example
One spinal cord level or segment innervating more than one muscle
Longitudinally - trapezius and sternocleidomastoid Tangentially - intercostals and obliques
157
# Define Poland anomaly
Congenital absence of pectoralis major
## Footnote
Poland anomaly is an underdevelopment or absence of the chest muscle on one side of the body and webbing of the fingers of the hand on the same side
158
What is unusual about **rectus sternalis?**
Not present in most of the population: considered a congenital anomaly/variation
159
**HemiScoliosis**
As the spine forms before birth, part of one vertebra (or more) may not form completely. When this occurs, the abnormality is called a hemivertebra
160
What is spina bifida occulta?
Spina bifida is a type of neural tube defect. The neural tube is the structure that eventually develops into the baby's brain and spinal cord
161
What is a chordoma? Where do they develop?
Chordoma is a slow growing cancer of tissue found inside the spine. Chordoma can happen anywhere along the spine.
It is most often found near the tailbone (called a sacral tumor)
or where the spine meets the skull (called a clival tumor). Chordoma is also called notochordal sarcoma.
162
elevated alpha-fetoprotein levels
a **neural tube defect** such as
**spina bifida**, a condition in which the bones of the spine don't close around the spinal cord, or
**anencephaly**, a condition in which the brain does not develop properly.
163
What symptoms are seen with **Hirschprune's** disease? What causes this?
Hirschsprung's (HIRSH-sproongz) disease is a condition that affects the large intestine (colon) and causes problems with passing stool. The condition is present at birth (congenital) as a result of missing nerve cells in the muscles of the baby's colon
164
What are the two ways that bones are derived? Give an example of each.
Intramembranous ossification - most flat bones of the skull, most of the clavicle Endochondral ossification - most limb bones
165
process of endochondral ossification
The following stages are:
## Footnote
(a) Mesenchymal cells differentiate into chondrocytes.
(b) The cartilage model of the future bony skeleton and the perichondrium form.
(c) Capillaries penetrate cartilage. Perichondrium transforms into periosteum.
