|
Eighth Week
|
Timing
|
Source |
| The adrenal glands are developing. |
8th week after conception |
Rugh, p 53 |
| By using Doppler or real-time ultrasonic
measurements, the brain can be visualized. |
8th week after fertilization |
Williams, p 30 |
| The chin is visible. |
8th ewek after fertilization |
England, p 81 |
| Ossification begins in the lower limbs,
and is first recognizable in the femur. |
8th week after fertilization |
Moore, p 97 |
| The feet are well-formed and distinctly
human. |
8th week after conception |
Rugh, p 53 |
| Local stimuli may induce partial closing
of the fingers. |
8th week after fertilization |
Williams, p 169 |
| The hands are well-formed and distinctly
human. |
8th week after conception |
Rugh, p 53 |
| Hiccups were observed in 12 of 12
fetuses studied, with a median frequency of about
50 hiccups per hour. |
8th week after conception |
de Vries (1985), p 108 |
| The permanent kidneys are forming. |
8th week after conception |
Rugh, p 54 |
| The lungs have lobes and many-branched
bronchioles. |
8th week after conception |
Rugh, p 53 |
| Purposeful limb movements first occur. |
8th week after fertilization |
Moore, p 97 |
| Local stimuli may evoke opening the
mouth. |
8th week after fertilization |
Williams, p 169 |
| If the fetus is removed from the uterus,
spontaneous movements may be observed. |
8th week after fertilization |
Wiliams, p 169 |
| The beginnings of all essential structures
are present. |
8th week after fertilization |
Williams, p 154 |
| Local stimuli may evoke squinting. |
8th week after fertilization |
Williams, p 169 |
| Taste buds begin to form. |
8th week after conception |
Rugh, p 53 |
| The ovary is present. |
8th week after fertilization |
England, p 167 |
| Breathing movements are first seen. |
8th wek after conception |
Roodenburg, p 32 |
| A single, large displacement of the
diaphragm is sometimes similar to a sigh. |
8th week after conception |
Nijhuis/de Vries, p 6 |
| Insertion of the fingers into the
mouth has been observed. |
8th week after conception |
Nijhuis/de Vries, p 7 |
| Stretches first occur. |
8th week after conception |
Roodenburg, p 33 |
| Dental buds are present. |
8th week |
Sadler, 7th edition, p 341 |
| Jaw openings first occur. |
8 1/2 - 10 1/2 weeks after conception |
Nijhuis/de Vries, p 5 |
| Forward head movements first occur. |
8 1/2 - 12 1/2 weeks after conception |
Nijhuis/de Vries, p 5 |
| Stretches first occur. |
8 1/2 - 13 1/2 weeks after conception |
Nijhuis/de Vries, p 5 |
| The auricles of the external ear start
to take on their final shape. |
End of 8th week after fertilization |
Moore, p 100 |
| The eyelids are closing. |
End of 8th week after fertilization |
Moore p 99-100 |
| By the end of the 8th week after conception,
the face clearly looks human. |
End of 8th week after fertilization |
Moore, p 239 |
| All areas of the limbs are apparent.
In addition, the digits have lengthened and are
completely separated. |
End of week 8 after fertilization |
Moore, p 97 |
| The neck region is established. |
End of 8th week after fertilization |
Moore, p 99 |
| The neck is developed. |
End of 8th week after fertilization |
England, p 96 |
| The term embryo refers to the developing
human being during the first eight weeks after conception.
At the end of this period, all major structures
have started to form. |
End of 8th week after fertilization |
Moore, p 3 |
| The embryonic period concludes at
the end of the 8th week after fertilization and
the fetal period begins. Few, if any, new structures
are formed after this time. Develpment during the
fetal period involves growth and maturation of structures
that are already present. |
End of 8th week after fertilization |
Williams, p 153 |
| The embryonic period consists of the
first eight weeks after the last ovulation. During
this time, the overwhelming majority ( several thousand)
of the named human structures appear, and the embryo
is about 30 millimeters in length. |
End of 8th week |
O'Rahilly, p 55 |
| Scientists have examined the embryonic
period in far greater detail than the fetal period,
which begins in the ninth week and continues until
birth. Few new features appear during the fetal
period. Instead, the structures that are already
present continue to develop. |
End of 8th week |
O'Rahilly, p 55 |
| The initial formation and development
of nearly all of the organs is complete and the
organs can be identified in a grossly recognizable
state. |
End of 8th week of pregnancy |
Carlson, p 407 |
| The head is disproportionately large
compared with the rest of the body. |
End of 8th week of pregnancy |
Carlson, p 407 |
| The embryo has human characteristics.
The neck area is established and the eyelids are
obvious and are closing. The auricles of the external
ears begin to take their final shape. |
End of 8th week after fertilization |
Moore, p 99 |
| The face is unmistakably human. |
2nd month after conception |
Rugh, p 54 |
| Breathing movements are first seen. |
8-9 1/2 weeks after conception |
Nijhuis/de Vries, p 5 |
| Hand-to-face contacts first occur. |
8 - 10 1/2 weeks after conception |
Nijhuis/de Vries, p 5 |
| The hand touches the face slowly and
the fingers often open and close. |
8 - 10 1/2 weeks after conception |
de Vries (1982), p 309 & p 311 |
| Limb movements first occur during
the 8th week. By the 14th week, they become coordinated. |
8th - 14th weeks after fertilization |
Moore, p 112 |
| External examination can reveal whether
the embryo is male or female. |
Day 50 after conception |
Rugh, p 7 |
| The face is more human-like. |
Days 50 - 56 after fertilization |
Sadler, p 110 |
| The fingers are free. |
Days 50-56 |
Sadler, p 110 |
| The limbs are long and bent at the
elbows and knees. |
Days 50-56 of development |
Sadler, p 110 |
| The toes are free. |
Days 50-56 |
Sadler, p 110 |
| The hand plates are slightly flexed
at the wrists. |
Day 52 of devleopment |
Larsen, p 209 |
| The upper limbs are slightly bent
at the elbows. |
Day 52 of development |
Larsen, p 209 |
| The eye is heavily pigmented. |
About 52 days after fertilization |
Moore, p 100 |
| The fingers are separated. |
About day 52 after fertilization |
Moore, p 100 |
| The nose is stubby. |
About day 52 after fertilization |
Moore, p 100 |
| The toes are beginning to separate. |
About day 52 after fertilization |
Moore, p 100 |
| The fingers are free and longer. |
Days 52-53 after fertilization |
Moore, p 91 |
| The auricle, or external ear, is visible. |
Day 54 after fertilization |
England, p 92 |
| The ankles are present. |
Day 54 after fertilization |
England, p 181 |
| The toes are free and longer. |
Days 54-55 after fertilization |
Moore, p 91 |
| The major blood vessels of the body
take on their final scheme. |
Day 56 after conception |
Rugh, p 53 |
| The face appears to be quite human. |
Day 56 after conception |
Rugh, p 53 |
| The fingers of both hands are usually
found close to the nose. |
Day 56 after conception |
Rugh, p 53 |
| Digit separation in the hand is complete. |
Day 56 |
Sadler, p 175 |
| All regions of the arms and legs are
well-developed, including the toes. |
Day 56 of development |
Larsen, p 213 |
| Muscular layers of the stomach, esophagus,
and intestines begin to proliferate. |
Day 56 after conception |
Rugh, p 53 |
| The primary teeth are at the cap stage. |
Day 56 after fertilization |
Larsen, p xii |
| The embryo has a distinct human appearance. |
About day 56 after fertilization |
Moore, p 100 |
| The mouth is present. |
About day 56 after fertilization |
Moore, p 100 |
| The lower jaw is developing. |
About day 56 after fertilization.
|
Moore, p 100 |
| The shoulders are developing. |
About day 56 after fertilization |
Moore, p 100 |
| The toes are separated. |
About day 56 after fertilization |
Moore, p 100 |
