Human Development- EXAM I Flashcards
1
Q
What the are three main stages of human development and when do they take place?
A
Proliferation period: (0-3 weeks)
Embryonic period: (3-8 weeks)
Fetal development period (9 weeks to term)
2
Q
Fertilization of the ovum yields a:
A
Zygote
3
Q
The zygote has a full compliment of genetic material rendering it:
A
Diploid
4
Q
The zygote undergoes mitotic division forming a:
A
Blastomere
5
Q
Greater than 32 blastomeres creates a:
A
Morula
6
Q
At what cell stage foes the morula develop an internal blastocystic cavity?
A
64 cell stage
7
Q
When the morula develops an internal blastocystic cavity it is now referred to as:
A
Blastocyst
8
Q
Any mass that is lined with any type of cell (typically an epithelium), hollow inside, and sometimes filled with fluid:
A
Cyst
9
Q
The blastocyst will start traveling down the uterus and:
A
Implants itself into the uterine wall
10
Q
Once the blastocyst implants itself into the uterine wall it will create arms that anchor it in place called:
A
Syncytiotrophoblasts
11
Q
The blastocyst develops an inner cells mass at 6-7b days and is now referred to as an:
A
Embryoblast
12
Q
Implantation of the embryoblast into the uterine wall begins at day _____ and is complete at day _____
A
4; 10
13
Q
After the blastocyst implants into the uterine wall it will become:
A
Enveloped into the uterine wall
14
Q
The inner cell mass of the embryoblast transitions into the:
A
Bilaminar embryonic disc
15
Q
At the stage in which the embryoblast envelopes into the uterine wall and becomes bilmainar disc it is now able to receive:
A
Blood supply, nutrients & protection
16
Q
The outter cell mass of the bilaminar embryonic disc becomes the _____ & _____ layers
A
Cytotrophoblast & Syntrophoblast
17
Q
The Cytotrophoblast & Syntrophoblast layers are precursors to the:
A
Placenta
18
Q
What two layers make up the bilaminar embryonic disc?
A
Epiblast layer & Hypoblast layer
19
Q
The epiblast layer of the bilaminar disc is comprised of:
A
Ectoderm & mesoderm
20
Q
The hypoblast layer of the bilaminar disc is comprised of:
A
Endoderm
21
Q
The large cavity that forms at the top, just under the hypoblast forms the:
A
Yolk sac
22
Q
The development of a secondary cavity above the epiblast forms the:
A
Amniotic cavity
23
Q
List the structures associated with the bilaminar embryonic disc: (6)
A
- Epiblast layer
- Hypoblast layer
- Amniotic cavity
- Blastocyst cavity
- Syntrophoblasts
- Cytotrophoblasts
24
Q
Enlargement of the amniotic cavity & migration of cells out of the hypoblast form the:
A
Heuser’s membrane
25
The Heuser's membrane will form the internal lining of the blastocyst cavity- now called the:
Yolk sac
26
The internal lining of the yolk sac cavity:
Heuser's membrane
27
The cell layer surrounding the blastocyst (completely enveloped in the uterine wall):
Chorionic layer
28
During the third week of development, the bilaminar embryonic disc is characterized by the formation of:
Primitive streak, notochord, neural tube
29
The cleft that starts to form on the surface of the bilaminar disc during week three of development:
Primitive streak
30
During the third week of development, the bilaminar disc embryonic disc is characterized by the formation of the primitive streak, notochord and neural tube-
The three distinct germ layers at this point in development are:
Ectoderm, Mesoderm & Endoderm
31
The distinct embryonic germ layer that was formerly the epiblast layer:
Ectoderm
32
The distinct embryonic germ layer that was formerly the hypoblast layer:
Endoderm
33
Cells from the epiblast layer invaginate in to form the _____ during the third week of development
Mesoderm
34
The primitive streak is characterized by the formation of:
Pit, Node, & groove
35
______ cells invaginate within the ______ & migrate towards the cephalad until they reach the _______
Pre-notochordal
Primitive node
Prechrodal plate
36
The pre-notochordal cells invaginate within the primitive node & migrate towards the cephalad plate. They detach themselves from the ectodermal layer to line within the mesoderm forming the:
Notochord
37
Functions as a primitive skeletal support of the embryo around which the axial skeleton later forms:
Notochord
38
The notochord induces formation of:
Somites
39
Precursor of the vertebral column, ribs, associated back muscles & overlying dermis
Somites
40
The forms is what position:
Midline
41
The notochord is formed from ____ cells
Ectodermal
42
The notochord is formed from ectodermal cells derived from the:
Primitive streak
43
The notochord functions as a primitive axial skeleton for the embryo, establishing:
Symmetry & polarity of development & induction of the somites
44
The three layers of mesoderm during the proliferation period of human development:
Paraxial
Intermediate
Lateral plate
45
What are the two categories of lateral plate mesoderm:
Parietal & Visceral
46
(Proliferation period)
List the derivatives of mesoderm
1. Paraxial mesoderm
2. Intermediate mesoderm
3. Lateral plate mesoderm
47
What is derived from the paraxial mesoderm?
Somites
48
What is derived from the intermediate mesoderm?
Urogenital system
49
What is derived from the parietal portion of the lateral plate mesoderm?
Mesothelial (serous) membranes that cover the peritoneal, pleural & pericardial cavities
50
What is derived from the visceral portion of the lateral plate mesoderm?
The thin serous membranes that cover individual organs including the stomach, pancreas & spleen
51
The epidermis, hair & nails are derivatives of the:
Ectoderm
52
The epithelium of the oral & nasal cavities & paranasal sinuses are derivatives of the:
Ectoderm
53
Salivary & endocrine glands are derivatives of:
Ectoderm
54
The nervous system is a derivative of:
Ectoderm
55
Tooth enamel is a derivative of:
Ectoderm
56
The GI tract epithelium & associated glands are derivatives of:
Endoderm
57
Ectoderm creates a lot of _______ derived tissues & organs
Epithelial
58
During what stage of human development does the neural tube develop?
Proliferation period
59
During the development of the neural tube-
We start with a notocord, neural fold and neural crest which will further develop into the:
Neural groove
60
During the development of the neural tube-
What joins to form the neural tube?
Neural crest cells
61
The neural tube is a precursor to the:
Spinal column
62
During the development of the neural tube-
In the midline area, the neural crest cells will form the:
Dorsal root ganglion
63
Spina Bifida, Meningocele, Meningomyelocele, Meningoencephalocele & Anencephaly are all what type of defects?
Neural tube related developmental defects
64
What occurs when the neural tube doesn't form all the way to the bottom due to folic acid deficiency?
Spina Bifida
65
What neural tube deficiency is characterized by an extrusion of arachnoid & dura mater out of the head?
Meningocele
66
What a neural tube deficiency is characterized by an extrusion of neural tissue & all three meninges out of the head?
Meningomyelocele
67
What neural tube deficiency is characterized by an extrusion of a ventricular cistern plus neural tissue out of the head?
Meningoencephalocele
68
What neural tube deficiency is a fatal defect characterized by lack of development of the cranium & brain?
Anencephaly
69
What neural tube defects are considered mild?
Spina Bifida & Meningocele
70
What neural tube defect is considered slightly more severe?
Meningomyelocele
71
What neural tube defect is considered most severe but not yet fatal?
Meningohydroencephalocele
72
What neural tube defect is fatal?
Anencephaly
73
What determines the severity of the neural tube defect?
The amount of tissue extruding out
74
Neural crest cells may also be referred to as:
1. Ectomesenchyme
2. Neuroectoderm
75
Neural tube defects occur in what stage of human development?
Proliferation period (0-3 weeks)
76
If we are talking about oral-facial development in regard to neural crest cells what stage of human development are we referring to?
Embryonic period (3-8 weeks)
77
Around what day of oral-facial development do we see the rostral neuropore closing, formation of heart prominence & somites, and formation of the caudal neuropore?
Around day 24 (+/- 1 day)
78
Around what day of oral-facial development do we see the hyoid arch begin to form, and when is it completely formed?
Around 24 days
Around 26 days
79
Around what day of oral-facial development do we see formation of the mandibular arch, forebrain prominence, tail, & third brachial arch?
Around day 26
80
Around what day of oral-facial development do we see formation of the fourth brachial arch, the lower limb bud, the lens placode & the upper limb bud?
Around day 28
81
Everything from the neck up to the ear are derived from the:
Pharyngeal arches
82
The pharyngeal arches can be compared to a stack of onion rings, each ring contains:
A blood vessel, its own cranial nerve and often will form its own cartilage
83
During oral-facial development (embryonic period) the 1st brachial groove will develop into:
External auditory canal
84
During oral-facial development (embryonic period) the first brachial pouch will develop into:
Eustachian tube
85
During oral-facial development (embryonic period) the second brachial pouch will develop into:
Palatine tonsils
86
During oral-facial development (embryonic period) the third brachial pouch will develop into:
Inferior parathyroids/thymus
87
During oral-facial development (embryonic period) the fourth brachial pouch will develop into:
Superior parathyroids/ultimobranchial body
88
Around what day of oral-facial development do the eyes and ears begin to form?
Around day 41
89
Between the 3th and 9th month describe the head & body growth of the fetus:
The head stays the same size while the body continues to grow larger
90
At month 3 of fetal development describe the head to body ratio:
50/50
91
List the processes formed during the development of the face:
1. Mandibular process
2. Maxillary process
3. Lateral nasal process
4. Median nasal process
92
The oral-facial development the oral cavity is known as:
Stomodeum
93
What connects the oral and nasal facial processes?
Philtrum
94
Clefts can be:
1. Palatal
2. Soft tissue
3. Lip
4. Nasal
95
What cause a palatal cleft:
Improper descending of the tongue
96
The palatal shelves fuse right at the:
Junction of the primary palate
97
Fusion of the medial nasal process with the maxillary process normally occur at what period of gestation?
5-6 weeks
98
Defective fusion of _____ process with the ______ process will result in a cleft lip
Medial nasal
Maxillary
99
Defective fusion of _____ results in a velft palate
Palatine shelves
100
Fusion of the palatine shelves normally begins during the _____ of gestation & is completed by the _____
8th week
12th week
101
45% of all clefts are:
Combined cleft lip/cleft palate
102
30% of all cleft cases are:
Isolated cleft palate
103
25% of all cleft cases are:
Isolated cleft lip
104
The incidence of cleft lip/cleft palate is:
_______ births in Chinese, Japanese & Native American populations
______ births in Caucasian populations
_______ births in Afro-American populations
1 in 500
1 in 700
1 in 500
105
The incidence of cleft palate alone is:
1 in 2,500 births
106
If one child is born with a cleft lip, there is a ____ chance of a second child exhibiting the same defect
40%
107
Known Teratogens involved in Congenital malformations:
Drugs, chemical & radiation
108
List the drugs that are known teratogens involved in congenital malformations:
1. Ethanol
2. Tetracycline
3. Dilantin
4. Lithium
5. Methotrexate
6. Warfarin
7. Thalidomide
8. Androgens
9. Progesterone
10. Retinoic acid
109
List the chemicals that are known teratogens involved in congenital malformations:
1. Methylmercury
2. Polychlorinated biphenyls
110
During oral-facial development what may develop at the line of fusion between the palatine shelves and primary palate?
Nasopalatine duct cyst
111
Small depression at the very back of the tongue:
Foramen cecum
112
The location in which thyroid gland forms during oral-facial development:
Foramen cecum
113
The second brachial arch on the outside overgrows the third & fourth arches to form a:
Cervical sinus
114
During what week of development does the cervical sinus (derived from the second brachial arch) usually get resorbed?
7th week
115
Failure of resorption of the cervical sinus result in formation of:
Lateral cervical cyst/Branchial fistula
116
A lateral cervical cyst or brachial fistula will typically form along what muscle?
Sternocleidomastoid muscle
117
The first brachial arch forms lateral-lingual swellings which ultimately form the:
Anterior portion of the tongue
118
The 1st brachial arch is innervated by:
Cranial nerve 5
119
The 2nd brachial arch gives ____ to the tongue
Innervation
120
The 3rd & 4th brachial arch form the:
Posterior portion of the tongue
121
If the embryonic precursor is brachial arch #1, the intermediate structures include: (3)
1. Median tongue bud
2. Foramen cecum
3. Lateral lingual swellings
122
If the embryonic precursor is brachial arch #1 and the intermediate structures include the median tongue bud, foramen cecum & lateral lingual swellings, the adult structures include: (3)
1. Overgrown by lateral lingual swellings
2. Origin of the thyroid ectoderm
3. Anterior 2/3 of tongue
123
If the embryonic precursor is brachial arch #2, the intermediate structures include:
Copula/Tuberculum impar
124
If the embryonic precursor is brachial arch #2 and the intermediate structures include Copula/Tuberculum impar, the adult structure includes:
Overgrown by the hypobrachial eminence
125
If the embryonic precursor is brachial arch #3, the intermediate structure is:
Hypobrachial eminence
126
If the embryonic precursory is brachial arch #3 and the intermediate structure is the hypobrachial eminence, the adult structure is the:
Posterior 1/3 of tongue
127
If the embryonic precursor is brachial arch #4, the intermediate structures include:
Minor contributions to the hypobrachial eminence
128
If the embryonic precursor is brachial arch #4, and the intermediate structure includes minor contributions to the hypobrachial eminence then the adult structure is:
None
129
Which brachial arches contribute the most to the tongue?
Brachial arches 1 & 3
130
Identify the cranial nerves responsible for innervation to each brachial arch:
Arch #1:
Arch #2:
Arch #3:
Arch #4:
Arch #6:
1. Trigeminal
2. Facial
3. Glossopharyngeal
4. Vagus
6. Hypoglossal
131
Brachial arch #1 is innervated by the trigeminal nerve which provides:
Sensory to the anterior 2/3 of tongue
132
Brachial arch #2 is innervated by the facial nerve which provides:
Taste (special sensory) to anterior 2/3 of tongue via chorda tympani branch
133
Brachial arch #3 is innervated by the glossopharyngeal nerve which provides:
Sensory the posterior 1/3 of tongue
134
Brachial arch #4 is innervated by the vagus nerve which provides:
Sensory to the extreme posterior 1/3 via the superior laryngeal branch
135
Brachial arch #6 is innervated by the hypoglossal nerve which provides:
Motor to all tongue muscles
136
Failure of the thyroglossal duct to involute causes:
Thyroglossal duct cyst
137
Thyroglossal duct cysts usually form around what location?
Midline
138
Failure of the thyroid gland to involute at all, will result in:
Ectopic lingual thyroid
139
Thyroid tissue sitting on top of the tongue due to failure of involution:
Ectopic lingual thyroid
140
The mandible, maleus, & incus are derived from:
Meckel's cartilage (1st brachial arch)
141
The stapes, styloid process, stylohyoid ligament & the lesser horn of hyoid are derived from:
Reichart's cartilage (2nd brachial arch)
142
The greater horn of hyoid is derived from cartilage from the:
3rd brachial arch
143
Thyroid cartilage is derived from cartilage from the:
4th brachial arch
144
Development of the external ear develops from six:
Auricular hillocks
