[5] PRELIMS | MILESTONES OF FETAL DEVELOPMENT Flashcards
The embryonic stage starts on ____ and continues until approximately the ____
starts on day 15; continues until the 8th week
3 Weeks - Embryonic disk becomes ____ and ____-shaped, with a ____ cephalic end and ____ caudal end
Embryonic disk becomes elongated and pear-shaped, with a broad cephalic end and narrow caudal end
3 Weeks - ____ has formed a long ____ tube for ____
Ectoderm has formed a long cylindrical tube for brain and spinal cord development
3 Weeks - ____ from the endoderm appear as a ____
GIT from the endoderm appear as a tube-like structure
3 Weeks - the most advanced organ is the:
Heart
4-5 Weeks - during days ____, the ____ (or a series of mesodermal blocks) form on either side of the embryo’s midline
During days 21 to 32, the somites (or a series of mesodermal blocks) form on either side of the embryo’s midline
4-5 Weeks - Prior to ____, arm and leg buds are ____, but the tail bud is ____
Prior to 28 days, arm and leg buds are not visible, but the tail bud is present
4-5 Weeks: The pharyngeal arches – which will form the ____, ____, and ____ – develop at this time
The pharyngeal arches – which will form the lower jaw, hyoid bone, and larynx – develop at this time
4-5 Weeks - The ____ appear now; these pouches will form the ____ and cavity of the ____, the ____, and the ____
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
4-5 Weeks - The primordial of the ____ are also present
The primordial of the ear and eye are also present
4-5 Weeks - During the ____, the ____ of the eye form and the ____ develop
During the fifth week, the optic cups and lens vessels of the eye form and the nasal pits develop
4-5 Weeks - Partitioning in the heart occurs with the dividing of the ____
Partitioning in the heart occurs with the dividing of the atrium
4-5 Weeks - Embryo has marked ____ body, accentuated by the ____ and the large head folded over a ____
Embryo has marked C-shaped body, accentuated by the rudimentary tail and the large head folded over a protuberant trunk
4-5 Weeks - By ____, the arm and leg buds are well developed, with ____ and foot plates. The ____, ____, and ____ show the most advanced development
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
4-5 Weeks - Brain has differentiated into ____ areas, and ____ pair of cranial nerves are recognizable
Brain has differentiated into five areas, and 10 pair of cranial nerves are recognizable
6 Weeks:
* ____ are more highly developed
* Trunk is ____ than in earlier stages
* ____ are recognizable
- Head structures are more highly developed
- Trunk is straighter than in earlier stages
- Upper and lower jaws are recognizable
6 Weeks:
* ____ are well formed
* ____ has developed and its caudal end is bifurcated for beginning ____
- External nares are well formed
- Trachea has developed and its caudal end is bifurcated for beginning lung formation
6 Weeks:
* ____ has formed
* ____ is developing
* ____ are developing rapidly
- Upper lip has formed
- Palate is developing
- Ears are developing rapidly
6 Weeks:
* ____ now has most of its definitive characteristics, and ____ begins to be established
* ____ starts to produce blood cells
- Heart now has most of its definitive characteristics, and fetal circulation begins to be established
- Liver starts to produce blood cells
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 ____
- 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
7 Weeks:
* Head of the embryo is rounder and nearly erect
* Eyes have shifted and are closer together
* Eyelids are beginning to form
7 Weeks: Prior to this time, the ____ formed one tube that ended in a blind pouch; they now separate into two tubular structures
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
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.
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.
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
- 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
8 Weeks:
* External genitals appear, but ____
* ____ opens with the perforation of the ____
- External genitals appear, but sex not clearly identifiable
- Rectal passage opens with the perforation of the anal membrane
8 Weeks:
* Circulatory system through the umbilical cord is ____
* ____ are beginning to form
* Large muscles are now capable of ____
- Circulatory system through the umbilical cord is well-established
- Long bones are beginning to form
- Large muscles are now capable of contracting
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.
- 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.
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)
- 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)
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 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
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 ____
- 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
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
- 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
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).
- 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).
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
- 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
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 ____.
- 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.
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 ____
- 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
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 ____
- 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
