[5] PRELIMS | MILESTONES OF FETAL DEVELOPMENT Flashcards

1
Q

The embryonic stage starts on ____ and continues until approximately the ____

A

starts on day 15; continues until the 8th week

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2
Q

3 Weeks - Embryonic disk becomes ____ and ____-shaped, with a ____ cephalic end and ____ caudal end

A

Embryonic disk becomes elongated and pear-shaped, with a broad cephalic end and narrow caudal end

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3
Q

3 Weeks - ____ has formed a long ____ tube for ____

A

Ectoderm has formed a long cylindrical tube for brain and spinal cord development

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4
Q

3 Weeks - ____ from the endoderm appear as a ____

A

GIT from the endoderm appear as a tube-like structure

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5
Q

3 Weeks - the most advanced organ is the:

A

Heart

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6
Q

4-5 Weeks - during days ____, the ____ (or a series of mesodermal blocks) form on either side of the embryo’s midline

A

During days 21 to 32, the somites (or a series of mesodermal blocks) form on either side of the embryo’s midline

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7
Q

4-5 Weeks - Prior to ____, arm and leg buds are ____, but the tail bud is ____

A

Prior to 28 days, arm and leg buds are not visible, but the tail bud is present

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8
Q

4-5 Weeks: The pharyngeal arches – which will form the ____, ____, and ____ – develop at this time

A

The pharyngeal arches – which will form the lower jaw, hyoid bone, and larynx – develop at this time

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9
Q

4-5 Weeks - The ____ appear now; these pouches will form the ____ and cavity of the ____, the ____, and the ____

A

The pharyngeal pouches appear now; these pouches will form the eustachian tube and cavity of the middle ear, the tonsils, and the parathyroid and thymus glands

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10
Q

4-5 Weeks - The primordial of the ____ are also present

A

The primordial of the ear and eye are also present

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11
Q

4-5 Weeks - During the ____, the ____ of the eye form and the ____ develop

A

During the fifth week, the optic cups and lens vessels of the eye form and the nasal pits develop

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12
Q

4-5 Weeks - Partitioning in the heart occurs with the dividing of the ____

A

Partitioning in the heart occurs with the dividing of the atrium

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13
Q

4-5 Weeks - Embryo has marked ____ body, accentuated by the ____ and the large head folded over a ____

A

Embryo has marked C-shaped body, accentuated by the rudimentary tail and the large head folded over a protuberant trunk

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14
Q

4-5 Weeks - By ____, the arm and leg buds are well developed, with ____ and foot plates. The ____, ____, and ____ show the most advanced development

A

By day 35, the arm and leg buds are well developed, with paddle-shaped hand and foot plates. The heart, circulatory system, and brain show the most advanced development

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15
Q

4-5 Weeks - Brain has differentiated into ____ areas, and ____ pair of cranial nerves are recognizable

A

Brain has differentiated into five areas, and 10 pair of cranial nerves are recognizable

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16
Q

6 Weeks:
* ____ are more highly developed
* Trunk is ____ than in earlier stages
* ____ are recognizable

A
  • Head structures are more highly developed
  • Trunk is straighter than in earlier stages
  • Upper and lower jaws are recognizable
17
Q

6 Weeks:
* ____ are well formed
* ____ has developed and its caudal end is bifurcated for beginning ____

A
  • External nares are well formed
  • Trachea has developed and its caudal end is bifurcated for beginning lung formation
18
Q

6 Weeks:
* ____ has formed
* ____ is developing
* ____ are developing rapidly

A
  • Upper lip has formed
  • Palate is developing
  • Ears are developing rapidly
19
Q

6 Weeks:
* ____ now has most of its definitive characteristics, and ____ begins to be established
* ____ starts to produce blood cells

A
  • Heart now has most of its definitive characteristics, and fetal circulation begins to be established
  • Liver starts to produce blood cells
19
Q

6 Weeks:
* Arms have begun to extend ____, and both arms and legs have ____, although they may still be webbed
* There is a ____ in the arms, which are more advanced in development than the legs
* Beginning at this stage, the prominent tail will ____

A
  • Arms have begun to extend ventrally across the chest, and both arms and legs have digits, although they may still be webbed
  • There is a slight elbow bend in the arms, which are more advanced in development than the legs
  • Beginning at this stage, the prominent tail will recede
20
Q

7 Weeks:
* Head of the embryo is rounder and nearly erect
* Eyes have shifted and are closer together
* Eyelids are beginning to form

A
20
Q

7 Weeks: Prior to this time, the ____ formed one tube that ended in a blind pouch; they now separate into two tubular structures

A

Prior to this time, the rectal and urogenital passages formed one tube that ended in a blind pouch; they now separate into two tubular structures

21
Q

7 Weeks: Intestines enter the ____ in the area of the umbilical cord (called ____). At this point, the beginnings of all essential external and internal structures are present.

A

Intestines enter the extraembryonic coelom in the area of the umbilical cord (called umbilical herniated). At this point, the beginnings of all essential external and internal structures are present.

22
Q

8 Weeks:
* Approximately ____ C-R
* Clearly resembles a human being
* ____ continue to develop
* ____ begin to fuse
* ____ of the external ears begin to assume final shape, but are still set low

A
  • Approximately 3 cm (1.2 in) long C-R
  • Clearly resembles a human being
  • Facial features continue to develop
  • Eyelids begin to fuse
  • Auricles of the external ears begin to assume final shape, but are still set low
23
Q

8 Weeks:
* External genitals appear, but ____
* ____ opens with the perforation of the ____

A
  • External genitals appear, but sex not clearly identifiable
  • Rectal passage opens with the perforation of the anal membrane
24
Q

8 Weeks:
* Circulatory system through the umbilical cord is ____
* ____ are beginning to form
* Large muscles are now capable of ____

A
  • Circulatory system through the umbilical cord is well-established
  • Long bones are beginning to form
  • Large muscles are now capable of contracting
25
Q

9-12 Weeks:
* At end of 9 weeks, fetus reaches a C-R length of ____ and weighs about ____
* Head is large and comprises ____
* At 12 weeks, the fetus reaches ____ C-R and weighs about ____.
* Face is ____, with the nose protruding, the chin small and receding, and the ear acquiring a more adult shape
* Eyelids close at about ____ and will not reopen until about the ____
* Some reflex movement of the lips suggestive of the ____ has been observed at ____.
* Tooth buds now appear
* Limbs are ____, with well-formed digits.

A
  • At end of 9 weeks, fetus reaches a C-R length of 5 cm (2 in) and weighs about 14 grams
  • Head is large and comprises almost half of the fetus’ entire size
  • At 12 weeks, the fetus reaches 7 to 8 cm C-R and weighs about 45 g (1.6 oz).
  • Face is well-formed, with the nose protruding, the chin small and receding, and the ear acquiring a more adult shape
  • Eyelids close at about 10th week and will not reopen until about the 28th week
  • Some reflex movement of the lips suggestive of the sucking reflex has been observed at 3 months.
  • Tooth buds now appear
  • Limbs are long and slender, with well-formed digits.
26
Q

9-12 Weeks:
* Fetus can ____ toward the palm and begins to make a tiny fist
* Legs are still ____ than the arms
* ____ completes its development
* Well-differentiated ____ appear
* ____ begin to produce urine
* ____ of the fetus now occur
* FHR can be ascertained by electronic devices between ____ weeks. ( ____ bpm)

A
  • Fetus can curl fingers toward the palm and begins to make a tiny fist
  • Legs are still shorter and less developed than the arms
  • Urogenital tract completes its development
  • Well-differentiated genitals appear
  • Kidneys begin to produce urine
  • Spontaneous movements of the fetus now occur
  • FHR can be ascertained by electronic devices between 8 and 12 weeks. (120-160 bpm)
27
Q

13-16 Weeks:
* A period of ____
* At 13 weeks, fetus weighs ____ and is about ____ in C-R length
* ____, or fine hair, begins to develop, especially on the head.
* Skin is ____
* More muscle tissue and body skeleton have ____ and hold the fetus ____
* ____ movements are present
* Fetus ____ arms and legs: makes sucking motions, swallows ____, and produces ____ in the ____
* By the beginning of ____, ____ is clearly identifiable

A
  • A period of rapid growth
  • At 13 weeks, fetus weighs 55 to 120 g and is about 10 to 17 cm in C-R length
  • Lanugo, or fine hair, begins to develop, especially on the head.
  • Skin is so transparent
  • More muscle tissue and body skeleton have developed and hold the fetus more erect
  • Active movements are present
  • Fetus stretches and exercises arms and legs: makes sucking motions, swallows amniotic fluid, and produces meconium in the intestinal tract
  • By the beginning of week 16, skeletal ossification is clearly identifiable
28
Q

20 Weeks:
* Fetus doubles its C-R length and now measures ____
* Fetal weight is ____
* Lanugo covers the ____ and is especially prominent on the ____
* Subcutaneous deposits of ____, which has rich blood supply, make the skin less transparent
* ____ now appear over the mammary glands
* Head is covered with ____, and the ____ are beginning to form
* ____ are present on both fingers and toes
* Muscles are ____, and fetus is active
* Quickening is felt
* Fetal heartbeat audible through a ____

A
  • Fetus doubles its C-R length and now measures 25 cm long
  • Fetal weight is 223 g
  • Lanugo covers the entire body and is especially prominent on the shoulders
  • Subcutaneous deposits of brown fat, which has rich blood supply, make the skin less transparent
  • Nipples now appear over the mammary glands
  • Head is covered with fine, woolly hair, and the eyebrows and eyelashes are beginning to form
  • Nails are present on both fingers and toes
  • Muscles are well-developed, and fetus is active
  • Quickening is felt
  • Fetal heartbeat audible through a fetoscope
29
Q

24 Weeks:
* The fetus at 24 weeks reaches a crown-to-heel (C-H) length of ____
* Weighs about ____.
* Hair on the head is ____, and eyebrows and eyelashes ____
* Eye is ____ and will soon open
* Fetus has a ____ and by the end of 6 months, has ____
* Skin covering the body is ____, with little subcutaneous fat
* Skin on hands and feet have ____, with skin ridges on palms and soles forming distinct ____
* Skin over entire body is covered with ____
* ____ in the lungs just beginning to form

A
  • The fetus at 24 weeks reaches a crown-to-heel (C-H) length of 28 to 36 cm
  • Weighs about 550 to 600 g.
  • Hair on the head is growing long, and eyebrows and eyelashes have formed
  • Eye is structurally complete and will soon open
  • Fetus has a reflex hand grip (grasp reflex) and by the end of 6 months has startle reflex
  • Skin covering the body is reddish and wrinkled, with little subcutaneous fat
  • Skin on hands and feet have thickened, with skin ridges on palms and soles forming distinct foot and fingerprints
  • Skin over entire body is covered with vernix caseosa
  • Alveoli in the lungs just beginning to form
29
Q

25-28 Weeks:
* At ____, fetal skin is still red, wrinkled, and covered with ____
* During this time, brain is developing rapidly, and the nervous system is complete enough to provide some ____
* Eyelids open and close under ____
* In the male fetus, testes begin to descend into the ____
* Respiratory and circulatory systems have developed though ____ still physiologically immature
* Fetus at 28 weeks is about ____ long C-H and weighs ____ (2 lbs, 10.5 oz to 2 lbs, 12 oz).

A
  • At 6 months, fetal skin is still red, wrinkled, and covered with vernix caseosa
  • During this time, brain is developing rapidly, and the nervous system is complete enough to provide some** degree of regulation of body functions**
  • Eyelids open and close under neural control
  • In the male fetus, testes begin to descend into the scrotal sac
  • Respiratory and circulatory systems have developed though lungs still physiologically immature
  • Fetus at 28 weeks is about 35 to 38 cm (14 to 15 in) long C-H and weighs 1200 to 1250 g (2 lbs, 10.5 oz to 2 lbs, 12 oz).
30
Q

29-32 Weeks:
* At 30 weeks, pupillary light reflex is present
* Fetus is gaining weight from an increase in body muscle and fat, and weighs about 1600 g, with a C-H length of about 38 to 43 cm (15 to 17 in) by 32 weeks of age
* CNS has matured enough to direct rhythmic breathing movements and partially control body temperature though lungs are not yet fully mature
* Bones are fully developed but soft and flexible
* Fetus begins storing iron, calcium, and phosphorus
* In males, the testicles may be located in the scrotal sac but often still high in the inguinal canals

A
  • At 30 weeks, pupillary light reflex is present
  • Fetus is gaining weight from an increase in body muscle and fat, and weighs about 1600 g, with a C-H length of about 38 to 43 cm (15 to 17 in) by 32 weeks of age
  • CNS has matured enough to direct rhythmic breathing movements and partially control body temperature though lungs are not yet fully mature
  • Bones are fully developed but soft and flexible
  • Fetus begins storing iron, calcium, and phosphorus
  • In males, the testicles may be located in the scrotal sac but often still high in the inguinal canals
31
Q

35-36 Weeks:
* Fetus begins to ____, and ____ covers the deposits of subcutaneous fat
* Lanugo begins to ____
* Nails reach the ____
* By ____ weeks of age, fetus has a ____ and exhibits ____
* By ____ weeks of age, weight is usually ____ (5 to 6 lb), and C-H length is about ____.

A
  • Fetus begins to get plump, and less wrinkled skin covers the deposits of subcutaneous fat
  • Lanugo begins to disappear
  • Nails reach the edge of fingertips
  • By 35 weeks of age, fetus has a firm grasp and exhibits spontaneous orientation to light
  • By 36 weeks of age, weight is usually 1,800 to 2,700 g (5 to 6 lb), and C-H length is about 42 to 48 cm.
32
Q

38-40 Weeks:
* Considered ____ at 38 weeks and up to 40 weeks after conception
* C-H length varies from ____ (19 to 21 in)
* Weight at term is about ____ (6 lb, 10 oz to 7 lb, 15 oz)
* Skin is ____ and has a ____
* The only lanugo left is on the ____
* Hair on the head is ____ but is coarse and about 1 in long
* Vernix caseosa is ____

A
  • Considered full term at 38 weeks and up to 40 weeks after conception
  • C-H length varies from 48 to 52 cm (19 to 21 in
  • Weight at term is about 3000 to 3600 g (6 lb, 10 oz to 7 lb, 15 oz)
  • Skin is pink and has a smooth, polished look
  • The only lanugo left is on the upper arms and shoulders
  • Hair on the head is no longer woolly but is coarse and about 1 in long
  • Vernix caseosa is present
33
Q

38-40 Weeks:
* Body and extremities are ____, with good ____, and fingernails extend ____
* Chest is ____ but still a smaller than the head, and mammary glands ____
* In males, the testes are in the ____
* As the fetus enlarges, amniotic fluid diminishes to about ____, and the fetal body mass ____
* Fetus assumes what is called its ____

A
  • Body and extremities are plump, with good skin turgor, and fingernails extend beyond the fingertips
  • Chest is prominent but still a smaller than the head, and mammary glands protrude in both sexes
  • In males, the testes are in the scrotum or palpable in the inguinal canals.
  • As the fetus enlarges, amniotic fluid diminishes to about 500 mL or less, and the fetal body mass fills the uterine cavity
  • Fetus assumes what is called its position of comfort, or lie