Exam 1 Flashcards
1
Q
The study of the embryo is called…
A
Embryology
2
Q
This is the study of all developmental processes from conception to death.
A
Ontogeny
3
Q
This is the part of ontogeny from conception to birth or hatching.
A
Embryogeny
4
Q
This is the process by which a cell or part of an embryo becomes restricted to a given developmental pathway.
A
Determination
5
Q
This is the complex of changes involved in progressive specialization of structure and function, often resulting in the formation of luxury molecules.
A
Differentiation
6
Q
(HYPERTROPHY/HYPERPLASIA) is the increase in cell numbers.
A
Hyperplasia
7
Q
(HYPERTROPHY/HYPERPLASIA) is the increase in cell size.
A
Hypertrophy
8
Q
This is the generation of form or assumption of new shape.
A
Morphogenesis
9
Q
An effect one embryonic tissue has upon another such that the development course of the responding tissue is qualitatively changed from what it would have been in the absence of this tissue.
A
Induction
10
Q
This is the process by which different tissues are brought together and combined to form organs and tissues.
A
Integration
11
Q
All development rests ultimately on the _____. These may be activated or inactivated throughout development.
A
Genes
12
Q
This is the generation and development of gametes (sperm and egg cells).
A
Gametogenesis
13
Q
The phases of gametogenesis include –
1) Extraembryonic origin of germ cells and their migration into the _____.
2) Increase in number of germ cells by ______.
3) Reduction in chromosomal number by ______.
4) Structural and functional maturation of the eggs and spermatozoa.
A
Gonads; Mitosis; Meiosis
14
Q
The first appearance of germ cells in human embryogenesis occurs _____ days after fertilization. Found in the endodermal layer of yolk sac.
A
24
15
Q
The migration route of germ cells in human embryogenesis goes from the yolk sac to the ______ ______, then through the ______ ______ and into developing gonads.
A
Hindgut epithelium; Dorsal mesentery
16
Q
This is the term for growths from misdirected migrating primordial germ cells. They contain mixtures of highly differentiated tissues.
A
Teratomas
17
Q
Female version of gametogenesis is called…
A
Oogenesis
18
Q
Male version of gametogenesis is called…
A
Spermatogenesis
19
Q
The female product of gametogenesis are ______, and the male product are ______.
A
Eggs; Spermatozoa
20
Q
The five sub phases of Prophase I in Meiosis are…
A
Leptotene Zygotene Pachytene Diplotene Diakinesis
21
Q
The major events in meiosis include the pairing of homologous chromosomes, called ______, and _________.
A
Synapsis; Crossing-over
22
Q
Meiosis starts with a (DIPLOID/HAPLOID) cell and ends with (DIPLOID/HAPLOID) cells.
A
Diploid; Haploid
23
Q
The major results of meiosis include –
- Increase in cell numbers sometimes
- Daughter cells are not genetically _______.
- Daughter cells are (DIPLOID/HAPLOID).
A
Identical; Haploid
24
Q
In this sub phase of Prophase I, the chromosomes are threadlike, each chromosome consists of two chromatids, and chromosomes begin to coil.
A
Leptotene
25
In this sub phase of Prophase I, the homologous chromosomes pair (synapsis), and the synaptonemal complex forms.
Zygotene
26
In this sub phase of Prophase I, there is maximum coiling, tetrads are formed, and crossing-over begins.
Pachytene
27
In this sub phase of Prophase I, crossing-over continues and the chiasmata are well-defined.
Diplotene
28
In this sub phase of Prophase I, crossing-over is complete, terminalization occurs, the spindle apparatus is in place, and the nuclear membrane is disrupted.
Diakinesis
29
In this stage of meiosis, tetrads line up along the equatorial plate and the centromeres do NOT divide.
Metaphase I
30
In this stage of meiosis, homologous chromosomes move to opposite poles. Each homologue consists of two chromatids. Chromatids are not genetically identical because of crossing-over. Daughter cells will be haploid.
Anaphase I
31
In this stage of meiosis, cytokinesis occurs (usually) and the nuclear membranes reform (maybe). The spindle apparatus disassemble and chromosomes may uncoil to varying degrees.
Telophase I
32
In this stage of meiosis, chromosomes condense again and the nuclear membranes disappear. The spindle apparatus reforms in each cell and each chromosome consists of two chromatids. Each daughter cell has one complete set of chromosomes (haploid).
Prophase II
33
In this stage of meiosis, chromosomes line up on equatorial plate.
Metaphase II
34
In this stage of meiosis, centromeres divide and chromosomes move to opposite poles. Each chromosome consists of a single chromatid.
Anaphase II
35
In this stage of meiosis, chromosomes uncoil and cytokinesis is complete. Nuclear membranes reform and the end result is four genetically unique haploid daughter cells.
Telophase II
36
(SOMATIC/GERM) cells are nonproductive cells, and (SOMATIC/GERM) cells are reproductive cells.
Somatic; Germ
37
This is the term for when chromosomes do not separate correctly and creates an abnormal number.
Nondisjunction
38
The term for an abnormal number of chromosomes is...
Aneuploidy
39
Examples of aneuploidy are ________ where there are 45 chromosomes, and _______ where there are 47 chromosomes (occurs in down syndrome).
Monosomy; Trisomy
40
Four changes that can occur in part of a chromosome are...
Translocations
Deletions
Inversions (3' to 5' instead of 5' to 3')
Duplications
41
The term for one or more complete sets of chromosomes is...
Euploidy
42
This is the term for non-viable, single set of chromosomes.
Monoploidy (haploidy)
43
This is the term for two complete sets of chromosomes.
Diploidy
44
This is the term for more than two complete sets of chromosomes (non-viable).
Polyploidy
45
Female primordial germ cells develop at a site distant from the gonads (as in spermatogenesis). They migrate to developing ovaries and become _______.
Oogonia
46
All oogonia develop into primary _______ in the early embryo.
Oocytes
47
In most mammalian species, primary oocytes begin the process of meiosis and reach the ________ stage of meiosis before or shortly after birth.
Diplotene
48
In humans, ____ million germ cells are present at embryonic midterm. At birth, about ____ million remain. The others undergo apoptosis.
7; 2
49
Shortly after birth, there are about ________ primary oocytes. Approximately _______ will survive to puberty. These will be arrested in the diplotene stage of meiosis, the rest will have become atretic.
400,000; 40,000
50
After puberty, at the beginning of each menstrual cycle, some of these oocytes resume meiosis until the second metaphase. About _____ will actually be ovulated, most will become atretic.
400
51
During the ______ period, the diploid oogonium is not surrounded by follicle cells. There is no follicle and there is 1 chromatid/chromosome.
Fetal
52
In the later fetal period through birth, the primary oocyte had advanced to the diploid stage of meiosis. There is a primordial _______ with a few flattened _______ cells and there are 2 chromatids/chromosomes.
Follicle; Follicle
53
From birth to puberty, there is a diploid primary oocyte and a primary follicle with a single layer of cuboidal follicle cells. The oocyte and follicle cells are connected via _______ and _____ junctions.
Microvilli; Gap
54
From birth to puberty, the _____ _____ separates the primary oocyte from follicular cells and there are 2 chromatids/chromosomes.
Zona pellucida
55
After puberty per each ovulation cycle, some diploid primary oocytes resume meiosis to _________ stage.
Metaphase II
56
After puberty per each ovulation cycle, there is a secondary follicle with multiple layers of follicle cells and beginning of an ______ formation. Membrana granulosa surrounds the outside of the follicle cells.
Antrum
57
After puberty per each ovulation cycle, there 2 chromatids/chromsome within one haploid secondary oocyte and one haploid _____ _____.
Polar body
58
After puberty per each ovulation cycle, there is a tertiary follicle with multiple layers of follicle cells, ______ ______ and large antrum.
Corona radiata
59
The cells between the membrana granulosa and antrum are called _____ _____ cells.
Mural granulosa
60
The cells between the zone pellucid and antrum are called the ______ cells.
Cumulus
61
Prior to ovulation, there is a haploid secondary oocyte with ______ ______ and ______ cells plus a haploid polar body. There are 2 chromatids/chromosome.
Corona radiata; Thecal
62
Granulosa cells develop _____ receptors and ____ receptors.
FSH; LH
63
Circulating FSH stimulates granulose cells to produce _______.
Estrogen
64
Prior to ovulation, meiosis resumes and is arrested at metaphase II due to an _____ surge which shuts down gap junctions between granulosa cells and oocyte.
LH
65
______ concentration is reduced, allowing activation of MPF (maturation promoting factor).
cAMP
66
This component of a tertiary follicle will produce angiogenesis factor.
Theca externa
67
This component of a tertiary follicle contains LH receptors and secretes testosterone.
Theca interna
68
The membrana granulosa of tertiary follicles surround _____ _____ cells.
Mural granulosa
69
Mural granulosa cells develop _____ receptors and synthesize _______ in response to FSH.
FSH; Aromatase
70
Aromatase converts ________ into 17 Beta-estradiol.
Testosterone
71
Estrogens stimulate formation of _____ receptors on granulosa cells.
LH
72
This is what attaches the oocyte to the follicle wall and will facilitate release of the ovum at ovulation.
Cumulus (oophorus) cells
73
This component of the tertiary follicle is involved in fertilization.
Zona pellucida
74
A tertiary (Graafian) follicle is large and usually projects from the surface of the ovary like a blister. It takes about ____ days to develop from primordial follicle in humans and meiosis will only resume if the egg is _______.
9; Fertilized
75
Ovulation in most mammalian species occurs at which meiotic phase?
Metaphase II
76
After fertilization occurs, the second meiotic division is completed. Now there is a fertilized ovum and a second _____ _____. There is only 1 chromatid/chromosome, the diploid number is reestablished after fertilization.
Polar body
77
Eventually all oocytes are used up, mostly through atresia. Loss of all oocytes is followed by ________.
Menopause
78
A factor leading to meiotic arrest at the diplotene stage of meiosis includes a high concentration of ______ from oocyte and follicular cells. This inactivates MPF (maturation promoting factor).
cAMP
79
A factor leading to meiotic arrest at the diplotene stage of meiosis is the cGMP from follicular cells that inactive phosphodiesterase 3A in oocyte. This prevents the conversion of _______ to 5'AMP and maintains a high concentration of it.
cAMP
80
Heterosynthesis (from external sources) occurs via follicle cells or nurse cells. The yolk is manufactured in the ______.
Liver
81
Autosynthesis (from oocyte itself) occurs with ________ chromosomes and gene amplification (i.e., ribosomal RNA genes).
Lampbrush
82
The _______ _______ is a layer of follicle cells surrounding the oocyte. It interacts with the oocyte via microvilli and gap junctions.
Corona radiata
83
The _____ _____ is a non-cellular membrane surrounding the oocyte. It's secreted by the corona radiata and oocyte.
Zona pellucida
84
Put the following stages in mammalian ovulation in order from start to finish --
A. Activation of collagenase enzyme
B. LH surge
C. Activation of adenyl cyclase
D. LH binds to receptor sites on follicle cells
E. Progesterone secretion by follicle cells
F. Release of oocyte and corona radiata
1. B
2. D
3. C
4. E
5. A
6. F
85
The _______ of the uterine tube moves closer to the ovary and sweeps across the surface.
Fimbriae
86
In egg transport in the uterine tube, there is an increase in _______ of tube epithelial cells and an increase in activity of tubal _______ muscle cells.
Ciliation; Smooth
87
The egg and surrounding follicle cells is captured by the uterine tube. The egg is transported mostly via _________ of tubal smooth muscle.
Contractions
88
The transport time of the egg to the uterus (regardless of fertilization) has a portion of slow transport in the ________ that takes 72 hours and then a portion of rapid transport through the _______ that takes 8 hours. Total uterine arrival time is 3-4 days.
Ampulla; Isthmus
89
Slow transport of the egg through the ampulla (72 hours) requires what?
Progesterone
90
In spermatogenesis, put the following steps in order from first to last --
```
A. Spermatids (N) x4 cells
B. Primary spermatocytes (2N)
C. Primordial germ cells (2N)
D. Spermatogonia (2N)
E. Secondary spermatocytes (N) x2 cells
```
1. C
2. D
3. B
4. E
5. A
91
In the spermatogonia stage of spermatogenesis, there are Type A (stem cells) and Type B cells that leave the mitotic cycle and enter the meiotic cycle under influences of ______ ______.
Retinoic acid
92
The testes contain primitive sex cords, _______ _______ that contain the spermatogonia cells and sertoli cells, and the Cells of _______ (interstitial cells) which produce testosterone.
Seminiferous tubules; Leydig
93
What are the 4 developmental phases of a sperm (spermiogenesis) from beginning to end?
Golgi phase
Cap phase
Acrosomal phase
Maturation phase
94
In this phase of spermiogenesis, there are proacrosomal vesicles and acrosomal vesicles.
Golgi phase
95
In this phase of spermiogenesis, a mature acrosome forms a cap over the nucleus.
Cap phase
96
In this phase of spermiogenesis, the sperm rotates so that the acrosomal pole faces the wall of the seminiferous tubule and the cytoplasm is displaced toward the tail.
Acrosomal phase
97
In this phase of spermiogenesis, the flagellum and nuclear condensation is completed.
Maturation phase
98
Sperm histones are called...
Proamines
99
Acrosomal enzymes are synthesized under influence of mRNA synthesized during pre-leptotene stage of meiosis. These enzymes include _______, ______ ______ (in mammalian sperm), and other enzymes, phospholipids and carbohydrates.
Hyaluronidase; Zona lysin
100
The functions of these cells include physical support and maintenance, maintain and coordinate spermatogenesis, secrete estrogen, inhibin and anti-Mullerian factor, maintain blood-testis barrier, secrete tubular fluid, and phagocytize residual bodies of sperm cells.
Sertoli cells (sustentacular cells)
101
_______ cells form an immunological barrier between the forming sperm cells and the rest of the body and spermatogonia.
Sertoli
102
In the blood-testis barrier, surface adhesion complexes bind apical surfaces of Sertoli cells to late ________.
Spermatids
103
In the blood-testis barrier, surface adhesion complexes break down and release spermatids into the _______.
Lumen
104
In the blood-testis barrier, _______ fragments from surface adhesion complexes plus cytokines and proteinases break down the tight-junctional proteins of the blood testis barrier and allow developing spermatocytes to move closer to the lumen.
Laminin
105
_________ stimulates the formation of a new blood-testis barrier closer to the basal lamina.
Testosterone
106
LH secreted by the _______ _______ (in response to GnRH from hypothalamus) binds to LH receptors on interstitial cells of Leydig.
Anterior pituitary
107
Leydig cells synthesize testosterone from what?
Cholesterol
108
Testosterone is carried via the _______ to Sertoli cells (binds to cytoplasmic receptors) and to secondary sexual tissues including the prostate, seminal vesicle, epididymis, ductus deferent, penis, and scrotum.
Blood
109
FSH secreted by the _______ _______ (in response to GnRH from hypothalamus) binds to surface FSH receptors on Sertoli cells.
Anterior pituitary
110
Sertoli cells convert testosterone to ________ (compare with granulosa cells) and also synthesize Leydig cell stimulatory factor.
Estrogens
111
Sertoli cells produce _______-_______ protein which binds testosterone and is carried to fluid compartment of seminiferous vesicles.
Androgen-binding
112
After spermiogenesis, sperm undergoes (ACTIVE/PASSIVE) transport via testicular fluid, smooth muscle contractions, and cilia from seminiferous tubules (sperm are immotile).
Passive
113
The sperm will mature in the head of the ________ for 12 days. Here it undergoes changes in glycoproteins in the plasma membrane of the sperm head.
Epididymis
114
Sperm are capable of _________ by the time they reach the tail of the epididymis.
Fertilization
115
For ejaculation, the sperm goes through the...
Ductus deferens
116
For ejaculation, the sperm gets additions fluid from the _______ ______ and the _______.
Seminal vesicles; Prostate
117
The fluids from the seminal vesicles are...
Fructose
| Prostaglandins
118
The fluids from the prostate are...
Citric acid
Zn
Mg
Phosphatase
119
In the upper vagina, the seminal fluids act as a buffer for the acidity of the vaginal fluids. The pH in the upper vagina goes from 4.3 to ____.
7.2
120
In the cervix, the pH range is ____ to ____, which is optimal for sperm motility.
6.0; 6.5
121
In the cervical canal, there is a _______ block. Its composition and viscosity changes during mid-cycle from thick to thin and watery.
Mucous
122
In the cervical canal, there is an initial rapid transport where some spermatozoa reach uterine tubes within 5-20 minutes following ejaculation. This relies mostly on ________ movements of the female tract. These sperm are not as capable of fertilizing an egg.
Muscular
123
Spermatids mature into _________ through the process of spermiogenesis.
Spermatozoa
124
In the cervical canal, there is a slow transport of sperm that involves swimming through the cervical mucous, moving 2-3 mm per hour. The sperm can be stored in cervical ______ and may not reach oviducts for 2-4 days.
Crypts
125
Fertilization typically occurs in the _______.
Ampulla
126
In males, the testes continue to produce sperm throughout the lifetime of the individual (although this process decreases with age). This is because the _____ cells responsible for the production of sperm (spermatogonia cells) remain viable for the life of the individual.
Stem
127
This is the thickest layer of the uterus and is composed of smooth muscle tissue.
Myometrium
128
This layer of the uterine wall has a columnar surface epithelium, uterine glands, connective tissue storm, and spiral arterioles. It contains two separate layers, the functional layer and the basal layer.
Endometrium
129
In the cervix, the mucosal surface is characterized by numerous ______.
Crypts
130
In the cervix, the epithelium produces a glycoprotein-rich cervical mucous. The mucous composition varies throughout the uterine cycle, being thinnest around the time of _______.
Ovulation
131
What type of epithelium is the vagina lined with?
Stratified non-keratinized squamous
132
The vaginal epithelium secretes ________ throughout the menstrual cycle. Its breakdown products contribute to low pH of vaginal fluids.
Glycogen
133
The menstrual cycle is controlled by alternating levels of hormones, these hormones are...
FSH
LH
Estradiol
Progesterone
134
The menstrual cycle lasts an average of ____ days.
28
135
The hormone levels in the menstrual cycle are controlled by the ________ via the ________ pituitary.
Hypothalamus; Anterior
136
The two sub-cycles of the menstrual cycle include the...
Ovarian cycle
| Endometrial cycle
137
What are the substages of the ovarian cycle?
Follicular phase
Ovulation
Luteal phase
138
What are the substages of the endometrial cycle?
Menstrual phase
Proliferation phase
Secretory phase
139
The _______ phase of the ovarian cycle occurs during days 1-14 of the menstrual cycle.
Follicular
140
During this phase there is development of the mature Graafian follicle and secondary oocyte within the ovary.
Follicular phase
141
Development of the Graafian follicle is under the influence of ____ produced by the anterior pituitary as a result of its releasing factor from the hypothalamus.
FSH
142
The granulosa cells of the developing follicle secrete _______, which is responsible for the proliferation phase of the endometrium.
Estradiol
143
What occurs on day 14 of the menstrual cycle?
Ovulation
144
The stimulus for ovulation is a rise in levels of ____ and a sharp rise in ____ (also from the anterior pituitary).
FSH; LH
145
During ovulation, an _____ is released from the Graafian follicle.
Egg
146
The outer part of the Graafian follicle remains behind and is made up of thecal cells, which secrete ________.
Progesterone
147
During this phase the residual thecal and granulosa cells of the follicle, left over after ovulation, secrete estrogen and progesterone.
Luteal phase
148
In the luteal phase, breakdown of the membrana granulosa allows the growth of ______ ______ into the cavity of the ruptured follicle.
Blood vessels
149
Granulosa lutein cells secrete increasing amounts of progesterone plus some _______.
Estrogen
150
In the luteal phase, the residual theca and granulosa cells proliferate and form a large glandular structure called the ______ _______.
Corpus luteum
151
The progesterone and estradiol are necessary to maintain the __________ of the fertilized oocyte.
Implantation
152
In the luteal phase if fertilization does not occur, the corpus luteum regresses and levels of ________ and _______ decrease, resulting in the beginning of the next menstrual phase.
Progesterone; Estradiol
153
In the luteal phase if fertilization does not occur, then ________, which is released by the granulosa cells, inhibits the secretion of gonadotropins (especially FSH) resulting in regression of the corpus luteum.
Inhibin
154
In the luteal phase if fertilization does not occur, the replacement of granulosa lutein cells with collagenous scar tissue results in the formation of the ______ ______.
Corpus albicans
155
The breakdown of the corpus luteum in absence of fertilization late in the menstrual cycle is due to ________ and uterine luteolytic factors.
Apoptosis
156
In the luteal phase if fertilization does occur, then ______ ______ from future placental tissues maintains functional corpus luteum. The corpus luteum remains functional for several months into pregnancy.
Chorionic gonadotropin
157
In the luteal phase if fertilization does occur, then granulosa lutein cells are replaced by ______ lutein cells.
Theca
158
The endometrial cycle refers to the cyclic changes in the endometrium and lasts, on average, _____ days.
28
159
The endometrial cycle begins with the first day of _________ and ends 28 days later.
Menstruation
160
This endometrial sub phase lasts from days 1-4 or 5.
Menstrual phase
161
This endometrial sub phase lasts from days 4-14.
Proliferation phase
162
This endometrial sub phase lasts from days 15-28.
Secretory phase
163
In the ________ phase, the endometrial build-up from the previous cycle sloughs off, resulting in the menstrual flow.
Menstrual
164
Menstruation begins with ___________ of the spiral arteries that have been supplying the endometrium, followed by local ischemia.
Vasoconstriction
165
Vasoconstriction of the spiral arteries for menstruation is mediated by what?
Prostaglandins
166
During menstruation, _________ cells invade the area and continue the process of endometrial breakdown. Factors that inactivate the clotting process maintain bleeding until the lining is sloughed off.
Inflammatory
167
Endometrial growth increases the endometrial thickness from ____ mm to _____ mm by day 14.
1-2; 8-10
168
During the proliferation phase, blood vessels and ______ grow with the expanding endometrium.
Glands
169
In the proliferation phase, cells that initiate the growth come from the bases of the ______ that formed in the previous endometrium that were deep enough to survive the loss of the previous endometrium.
Glands
170
The proliferation phase is due to an increase in levels of _______ secreted by the granulosa cells of the developing ovarian follicle. Near the end of this phase there is a sharp rise in these levels.
Estradiol
171
During the secretory phase, levels of _______ decrease and the endometrial growth stops.
Estrogen
172
During the secretory phase, _______ glands develop more full and begin secretion.
Mucous
173
During the secretory phase, the ______ ______ in this area expand and heavily vascularize the area.
Spiral arterioles
174
The secretory phase is controlled by rising levels of _________, secreted by both the granulosa and thecal cells of the ovarian follicle.
Progesterone
175
The endometrial cycle essentially prepares the lining of the uterus to receive the fertilized egg. Implantation of the fertilized egg occurs about ____ days after ovulation.
7
176
This process is required for sperm to undergo acrosomal reaction and occurs inside the uterine tube in the isthmus. It requires the binding of the sperm to the tubal epithelium.
Capacitation
177
In capacitation, ________ must be removed from the sperm surface. It acts to inhibit premature capacitation.
Cholesterol
178
In capacitation, ________ (from epididymis) must be removed.
Glycoproteins
179
Capacitation is followed by a period of _________ and release of sperm in small numbers.
Hyperactivity
180
Put the following steps of fertilization in order from first to last --
```
A. Acrosomal reaction and penetration of zona pellucida
B. Prevention of polyspermy
C. Completion of egg meiosis
D. Development and fusion of male and female pronuclei
E. Penetration of corona radiata
F. Decondensation of the sperm nucleus
G. Attachment to zona pellucida
H. Binding and fusion of sperm and egg
I. Metabolic activation of the egg
```
1. E
2. G
3. A
4. H
5. B
6. I
7. F
8. C
9. D
181
Fusion of the outer ________ membrane with the sperm plasma membrane creates portals through which the contents of the _______ can be released.
Acrosomal; Acrosome
182
Fragmentation of fused acrosomal membrane and plasmalemma of the sperm results in the release of the acrosomal _______.
Enzymes
183
_________ is one of the major enzymes in the acrosome, it helps break down the hyaluronic acid component of the intercellular matrix between the corona radiata cells.
Hyaluronidase
184
________ movements of spermatozoa also help in the penetration through the corona radiata.
Swimming
185
____ is one of four glycoproteins that make up the zona pellucida (ZP). Attachment of the sperm to the ZP is mediated by this.
ZP3
186
ZP3 protein stimulates acrosomal reaction in mammals. It acts through ________ in the sperm plasma membrane.
G-proteins
187
In the acrosomal reaction, there is a massive influx of _______ ions through the sperm plasma membrane. There's also an exchange of _______ (influx) and ________ (efflux) ions, which increase the pH. This is followed by penetration of the sperm through the ZP.
Calcium; Sodium; Hydrogen
188
_______, a serine proteinase, is the most important enzyme involved in the penetration of the zona pellucida. It was originally referred to as zona lysin.
Acrosin
189
Acrosin (IS/IS NOT) released from the acrosome, but remains attached to the portion of the acrosomal membrane that fuses to the remaining sperm plasmalemma and overlies the nucleus.
Is not
190
Acrosin digests a small hole through the _____ _____ and assists in the penetration of swimming spermatozoa through it.
Zona pellucida
191
This term consists of a rapid depolarization of egg plasmalemma. It goes from -70 to +10 mV within 2-3 seconds and may last a little longer in mammals (several minutes). It temporarily prevents polyspermy.
Fast block
192
This term is mostly characterized by the release of polysaccharides from the cortical granules located just under the plasmalemma of the egg. Polysaccharides enter perivitelline space (between plasmalemma and the ZP) and become hydrated. Hydration produces a swelling that increases the width of the perivitelline space.
Slow block
193
Metabolic activation of egg is initiated by release of ________ ion within egg cytoplasm in response to introduction of phospholipase C zeta by sperm.
Calcium
194
The released calcium does the following --
- Initiates blocks to ________
- Stimulates increase in egg respiration and metabolism via the _______-_______ ion exchange mechanism
- Results in an increase in ____ and an increase in oxidative metabolism
Polyspermy; Sodium-Hydrogen; pH
195
Tight packing of sperm DNA is due to _______ cross-linking among protamine molecules. Sperm nuclear membrane becomes more permeable and allows entry of egg cytoplasmic factors which reduce this cross-linkage to sulfhydryl groups.
Disulfide
196
A ________ is the nuclear material of the head of the spermatozoan or of the oocyte after the oocyte has been penetrated by the spermatozoan. Each one normally carries a haploid set of chromosomes.
Pronucleus
197
This is the term used to denote the single-celled stage at which the male and female pronuclei have fused together and share a common membrane, establishing the diploid chromosome number.
Zygote
198
The two pregnancy dating systems include the _________ age, which dates the age of the embryo from time of fertilization, and the ________ age, which dates the age of the embryo from start of mother's last menstrual period (this one is two weeks greater).
Fertilization; Menstrual
199
Put the following post-fertilization events in order from first to last --
A. Implantation
B. This journey takes several days
C. Zygote becomes metabolically active
D. Zygote loses zona pellucida prior to implantation
E. Zygote is transported down uterine tube to uterus
F. Zygote begins to undergo cleavage (mitotic activity)
1. C
2. F
3. E
4. B
5. D
6. A
200
Zygote undergoes mitotic division to form an ____ cell embryo.
8
201
Compaction occurs when outer ________ adhere via gap junctions and appear to lose their individual identity. This involves E-cadherins and other calcium-dependent CAMs.
Blastomeres
202
The blastocyst consists of two types of cells, the outer layer called the _______, and the inner layer called the ______ _____ _____.
Trophoblast; Inner cell mass
203
Because of the eccentric placement of blastocoel and inner cell mass, the blastocyst is (NONPOLARIZED/POLARIZED).
Polarized
204
T/F. A morula comes after a blastocyst.
False. A morula is the 16-cell stage, and a blastocyst has 58 or more cells.
205
The ________ is the cavity formed by water transported into the morula (requires Na and K-ATPase transporters).
Blastocoel
206
Put the following stages of cleavage in order --
Morula
Blastomere
Blastocyst
Blastomere -- Morula -- Blastocyst
207
In humans, there is an ____ cell stage morula.
11
208
In invertebrates and non-mammalian vertebrates, early control of cleavage is through gene products transcribed from the (PATERNAL/MATERNAL) genome and embryonic gene products often do not appear until after blastulation.
Maternal
209
In mammalian embryos, maternal gene products are produced but generally are degraded by the ____ cell stage of development. By the ____ cell stage, most transcription is via the embryonic genome.
2; 4
210
__________ is the addition of ______ groups to specific regions of DNA molecules; it inactivates genes, including enhancers and promoters.
Methylation; Methyl
211
DNA of mature eggs and sperm is (HIGHLY/LOWLY) methylated.
Highly
212
Demethylation of maternal and paternal genomes occurs shortly after fertilization until the early _______.
Morula
213
Remethylation of inner cell mass occurs until late ________ stage.
Blastocyst
214
Methylation levels fall after ________ _______ cells enter genital ridges.
Primordial germ
215
Remethylation occurs later during __________ and may lead to maternal/paternal imprinting.
Gametogenesis
216
_________ of blastomeres determines whether cells are destined to become part of the inner cell mass or part of the trophoblastic group of cells.
Polarization
217
Polarization of blastomeres at 8-16 cell stages creates recognizable ______ and ______ surfaces.
Apical; Basal
218
This hypothesis states that the fate of a blastomere is determined by its position within the embryo, not from intrinsic properties.
Inside-Out Hypothesis
219
In the inside-out hypothesis, if a marked blastomere is inserted into the interior of a morula, it and its progeny become part of the...
Inner cell mass
220
In the inside-out hypothesis, if a marked blastomere is placed on the outside of a host morula, it and its descendants contribute to the...
Trophoblast
221
The other way that a blastomere's fate is determined is by the ______ ______ model. This depends on the plane of cell division during cleavage.
Cell Polarity
222
In the cell polarity model, if there is a cleavage plane parallel to the outer surface of the embryo then the outer daughter cell will become a (TROPHOBLAST/INNER CELL MASS) cell (polar) and the inner daughter cell will become an (TROPHOBLAST/INNER CELL MASS) cell (apolar).
Trophoblast; Inner cell mass
223
In the cell polarity model, if there is a cleavage plane perpendicular to the outer surface of the embryo, then both daughter cells become (TROPHOBLAST/INNER CELL MASS) cells.
Trophoblast
224
________ is the developmental potential, which is greater than fate. There are numerous genes involved in differentiation.
Potency
225
This gene involved in differentiation is essential for trophoblast cell differentiation. It's an antagonist for Oct-4.
Cdx-2
226
This gene involved in differentiation is expressed in developing oocytes and zygote and is required to permit cleavage to proceed to 2-cell stage. It is expressed in morula cell and may play a role in the maintenance of the undifferentiated state.
Oct-4
227
This gene involved in differentiation is produced by inner cells in late morula stage. It maintains integrity of inner cell mass along with Oct-4, and without it the inner cells differentiate into endoderm. Without Oct-4 the inner cells differentiate into trophoblast.
Nanog
228
This gene involved in differentiation is first expressed in 8-cell stage. Along with Oct-4 it helps to control regulation of genes involved in differentiation.
Sox2
229
________ ________ is differential gene expression depending on whether a chromosome is inherited from the male or the female parent. It refers to the observation that expression of certain genes derived from the egg differed from the expression of the same genes derived from the sperm. (i.e. Prader-Willi and Angelman syndromes)
Genomic imprinting
230
Parental imprinting occurs during _________. It typically involves methylation of DNA and imprinted genes are maintained throughout development and perhaps adulthood. Note that imprinting is erased and reestablished with each round of this.
Gametogenesis
231
This genomic imprinting disease is due to a mutation inherited from the father (deletion in long arm of chromosome 15). People have small hands and feet, short stature, poor sexual development, mental retardation, and voracious appetites (usually obese).
Prader-Willi Syndrome
232
This genomic imprinting disease is due to a mutation inherited from the mother (deletion in long arm of chromosome 15). People exhibit frequent laughter, uncontrolled muscle movement, a large mouth, and unusual seizures.
Angelman Syndrome
233
In mammals ________ is erased in the germ cells of each generation and then reestablished in the course of gamete formation. Sperm and eggs undergo different levels of this, resulting in the differential expression of male and female alleles in the offspring.
Methylation
234
X-inactivation takes place in humans during the first few weeks of development. Once the X chromosome is inactivated, it remains inactive in all descendants of the first cell. It's brought about by the action of ______, which is located on the X chromosome and produces an RNA molecule that coats the X chromosome and induces its inactivation.
Xist
235
Coating the X chromosome with Xist RNA causes the removal of ______ groups from histone proteins and the _______ of histones. This causes an alteration of histone composition.
Acetyl; Methylation
236
Mary Lyon proposed that the _____ _____ is an inactive X chromosome.
Barr body
237
X-inactivation is an example of _______ _______ and provides equal expression of X-chromosome products in both males and females.
Dosage compensation
238
________ refers to the ability of an embryo to compensate for the removal of structures or for addition of structures.
Regulation
239
________-________ genes are genes that contain a highly conserved sequence of 180 nucleotides called the homeobox which codes for the 60 amino acid homeodomain found in homeodomain transcription factor proteins.
Homeobox-Containing
240
Homeobox-containing genes play a major role in vertebrates with regard to _________ segmentation, not only along main body axis but within the development of many organs. Activated in a 3' to 5' direction (opposite of transcription direction).
Cranio-Caudal
241
Loss-of-function mutations result in (ANTERIOR/POSTERIOR) to (ANTERIOR/POSTERIOR) transformations.
Posterior to Anterior
242
Gain-of-function mutations result in (ANTERIOR/POSTERIOR) to (ANTERIOR/POSTERIOR) transformations.
Anterior to Posterior
243
This homeobox-containing gene family includes up to 100 genes. It plays a role in inducing mesodermal germ layer and in coordinating the outgrowth of the arm or leg.
T-box (Tbx) genes
244
Helix-loop-helix genes code for basic helix-loop-helix transcription factors. Basic regions of proteins bind to DNA. Helix-loop-helix is involved in homodimerization and heterodimerization and important in ________.
Myogenesis
245
This homeobox-containing gene is a type of helix-loop-helix family that is expressed in many developing organs throughout the body.
Forkhead (Fox) genes
246
_____ _____ transcription factors have zinc ions bound to polypeptide chain that cause the chain to form finger-like projections that can be inserted into the DNA helix.
Zinc finger
247
This transcription factor gene family has a high-mobility group domain that binds to the minor groove on the DNA helix rather than the major groove. This family includes the SRY gene.
Sox
248
This transcription factor gene family is important for the development of the embryonic kidney and the adult kidney. It takes its name from Wilms tumor, which is a kidney tumor that develops in children.
WT1
249
In drosophila, gap genes, pair-rule genes, and segment-polarity genes are all a type of __________ gene.
Segmentation
250
In drosophila, antennapedia complex (Hox genes) and bithorax complex (Hox genes) are ________ genes.
Homeotic
251
_____ _____ genes are important in the establishment of the dorsal-ventral and anterior-posterior axes in the fruit fly.
Egg polarity
252
Egg polarity genes include genes that establish the dorsal-ventral axis, which are...
Dorsal
Cactus
Toll
253
Egg polarity genes include genes that establish the anterior-posterior axis, which are...
Bicoid
Nanos
Hunchback
254
In drosophila, the ______ protein is a product of the dorsal gene and is express in the ovary.
Dorsal
255
In drosophila, the ______ protein, a product of the cactus gene, is also expressed in the ovary and binds to the dorsal protein and traps it in the cytoplasm.
Cactus
256
In drosophila, the _____ protein, produced by the toll gene, is also expressed in the ovary and leads to the degradation of the cactus protein, allowing the dorsal protein to move into the nuclei of the ventral cells.
Toll
257
Egg polarity genes are transcribed into mRNAs in the ovary during egg formation. The mRNAs migrate into the eggs and are translated into proteins after fertilization. This is an example of ______ ______ effect.
Genetic maternal
258
Egg polarity genes work by setting up protein _______ _______.
Concentration gradients
259
A protein that varies in concentration and causes different developmental responses as a result of the concentration differences is called a...
Morphogen
260
_______ expressed in the ovary regulates expression of genes responsible for anterior structures and stimulates hunchback. Its mRNA becomes anchored to the anterior end of the egg as it passes into the egg from the ovary. (In Drosophila)
Bicoid
261
The ______ gene is expressed in the ovary and regulates the expression of genes responsible for posterior structures. It inhibits translation of hunchback mRNA. (In Drosophila)
Nanos
262
________ regulates transcription of genes responsible for anterior structures in Drosophila.
Hunchback
263
In drosophila, expression of the segmentation genes is regulated by the ______ and ______ protein gradients.
Bicoid; Nanos
264
Three classes of segmentation genes include --
_____ genes, which delete adjacent segments.
_____ genes, which delete same part of pattern in every other segment.
_____ genes, which affect polarity of segment.
Gap
Pair-rule
Segment-polarity
265
In this drosophila mutation, the anterior segments are eliminated.
Kruppel
266
In this drosophila mutation, even-numbered segments are deleted.
Even-skipped
267
In this drosophila mutation, the posterior half of each segment is replaced with the anterior half of the adjacent segment.
Gooseberry
268
______ genes (in drosophila) determine the identify of individual segments. Products of these genes activate other genes that encode these segment-specific characteristics.
Homeotic
269
In drosophila, an example of a homeotic gene mutation is ________, which occurs when the antenna have been replaced with legs.
Antennapedia
270
Homeotic genes contain a _______.
Homeobox
271
Two major groups of homeotic genes in Drosophila are the _______ complex, which affects the development of the head and throat, and the _______ complex, which affects the development of the posterior thorax and abdominal segments.
Antennapedia
| Bithorax
272
The genes involved in development code for a variety of mRNAs which usually code for specific polypeptides/proteins are...
Transcription factors
Signaling molecules
Receptor molecules
273
This type of pathway is established when a ligand (signaling molecule) binds to a receptor.
Signal transduction pathways
274
List 4 signaling factor families...
Transforming Growth Factor-Beta Superfamily
Fibroblast Growth Factor Family
Hedgehog Family
Wnt Family
275
This member of the transforming growth factor-beta superfamily is a disulfide-linked dimer and synthesized as a pair of inactive 390 amino acid precursors. It consists of a large proregion and a bioactive region.
TGF-Beta1
276
In TGF-Beta1, the large proregion is enzymatically cleaved from the bioactive region. ____ bioactive regions and ____ proregions are secreted. ____ bioactive regions form a dimer. The proregions complex with the bioactive dimer and maintain it in a latent form. Activation occurs when the proregions are separated from the bioactive dimer. Bioactive dimer functions as a signaling molecule.
2; 2; 2
277
This growth factor family is related to the segment polarity molecule in Drosophila. It includes Desert, Indian, and Sonic hedgehog.
Hedgehog Family
278
This growth factor family includes 18 members in the mouse and is related to segment polarity gene in Drosophila. Often interacts with components of extracellular matrix and plays different roles in various vertebrate classes.
Wnt Family
279
Receptor molecules and be ________ or on the _____ _____.
Intracellular; Cell surface
280
Cell surface receptors include receptors with intrinsic ______ ______ activity and receptors that utilize a second messenger system.
Protein kinase
281
Cell surface receptors with intrinsic protein kinase activity includes receptors for ________ growth factors. The cytoplasmic domain possesses _______ kinase activity.
Fibroblast; Tyrosine
282
Cell surface receptors with intrinsic protein kinase activity include receptors for ______ factors. The cytoplasmic domain possesses ______/______ kinase activity.
TGF-Beta; Serine; Threonine
283
Put the following Delta-Notch pathway components and actions in order from first to last --
A. Complex enters nucleus
B. Notch-Deltex-Suppressor of hairless complex binds to Enhancer of split.
C. Delta (signal molecule) on dominant cell
D. Proteolytic cleavage of Notch intracellular domain
E. Complex binds to Suppressor of hairless
F. Notch intracellular domain complexes with Deltex
G. Notch receptor on a neighboring cell
H. Resultant inhibitory signal represses gene expression
1. C
2. G
3. D
4. F
5. A
6. E
7. B
8. H
284
This is a type of signaling between a dominant cell and neighboring cells (i.e., Delta-Notch).
Lateral inhibition
285
Dominant cell refers to a cell in a population that begins to ________ along a particular path.
Differentiate
286
Dominant cell expresses ______ signaling molecules on its cell membrane.
Delta
287
Delta then binds to _______ receptors on neighboring cells and, via the pathway, (REPRESSES/EXPRESSES) genes in the neighboring cells.
Notch; Represses
288
Fibroblast growth factor signaling molecules use which type of pathway?
Receptor tyrosine kinase pathway
289
Transforming growth factor-Beta signaling molecules (TgF-B) use which type of pathway?
Receptor tyrosine kinase pathway
290
In the receptor tyrosine kinase pathway for fibroblast growth factor signaling molecules, put the following components and actions in order from start to finish --
A. G protein is activated
B. ERK translocates to nucleus and activates various transcription factors
C. FGF binds to receptor tyrosine kinase
D. Activation of pathways components: RAS, RAF, MAP kinase, and ERK
1. C
2. A
3. D
4. B
291
In the receptor tyrosine kinase pathway for TgF-B signaling molecules, put the following components and actions in order from start to finish --
A. Smad dimer translocates to nucleus and binds to co-factors which can then bind to DNA regulatory factors
B. Receptro type II dimerizes with receptor type I
C. TgF-B binds to serine/threonine kinase receptor type II
D. Activation of pathways components: R-Smad and Co-Smad which dimerize
1. C
2. B
3. D
4. A
292
Put the following Hedgehog pathway components and actions in order from start to finish --
A. Uninhibited Smoothened signals the release of transcription Gli from a complex on microtubules
B. Shh-cholesterol is translocated to cell surface via the action of Dispersed (product of dispersed gene)
C. Gli translocates to the nucleus and influences gene expression
D. Sonic hedgehog protein is complexed with cholesterol shortly after being translated in sending cell
E. Shh-cholesterol inhibits the inhibitory actions of Patched on Smoothened on the target cell
1. D
2. B
3. E
4. A
5. C
293
Put the following Wnt Signaling Pathway components and actions in order from start to finish --
A. Disheveled prevents the degradation of the Beta-catenins by the destruction complex
B. Wnt molecule (ligand) binds to Frizzled on target cell
C. Frizzled interacts with intracellular Disheveled
D. Beta-catenins translocate to nucleus and activates transcription factors
1. B
2. C
3. A
4. D
294
In the absence of Wnt, _______ are bound to an intracellular destruction complex within the target cell.
Beta-catenins
295
Small RNAs, called _______, are small noncoding RNAs that influence gene expression.
MicroRNAs (MiRNAs)
296
There are two major groups of MiRNAs, ________ RNAs act during gametogenesis (esp. spermatogenesis) and ________ _______ _______ RNAs are expressed in somatic tissues throughout development.
Piwi-interacting RNAs (piRNAs)
| Endogenous small interfering RNAs (endo-siRNAs)
297
Put the following MicroRNA pathway actions and components in order from first to last --
A. Small miRNA molecule is complexed with an Argonaute (AGO) protein
B. The double helical precursor molecule, often containing a hairpin loop, is cleaved by Dicer
C. The AGO/miRNA complex approaches the target mRNA and through its intrinsic RNase activity, it cleaves the target mRNA and inactivates it.
1. B
2. A
3. C
298
Put the following Retinol pathway components and actions in order from first to last --
A. Retinol is released into the cytoplasm and binds to a CRBP 1
B. Retinoic acid binds to the dimer RXR-RAR which binds to RARE which activates transcription
C. Retinol (Vitamin A) as a signal molecule binds to an extracellular retinol-binding protein (RBP)
D. The retinol-RBP complex binds to a membrane RBP
E. After a series of enzymatic transformations, retinoic acid is bound to CRABP 1 and translocated into the nucleus
1. C
2. D
3. A
4. E
5. B
299
Fertilization typically occurs in the upper _______ within 12 hours after ovulation.
Ampulla
300
At the end of day 1, the 2-cell stage is in the ______.
Isthmus
301
By day 3, the _______ is in the isthmus and the corona radiata is lost by this time.
Morula
302
By day 4, the ________ is in the uterus.
Blastocyst
303
By day 5, the ______ ______ is lost.
Zona pellucida
304
By day 6, it is the beginning of ________.
Implantation
305
The zona pellucida surrounds the developing embryo until it reaches the uterus. The shedding of the zona pellucida is accomplished through a process called blastocyst _______.
Hatching
306
Put the following stages in implantation from first to last --
A. Erosion of the maternal vascular supply
B. Penetration of the uterine epithelium
C. Invasion into the tissues underlying the epithelium
D. Attachment of expanded blastocyst to the endometrial epithelium
1. D
2. B
3. C
4. A
307
The initial contact of the expanded blastocyst to the endometrial epithelium is between the endometrial surface and embryonic ______ of the blastocyst.
Pole
308
Attachment of the expanded blastocyst to the endometrial epithelium is facilitated by adhesion molecules (i.e., integrins) expressed by the endometrium and additional adhesion molecules expressed by the ________ cells.
Trophoblast
309
For the attachment of the expanded blastocyst to the endometrial epithelium, _________-________ factor expressed by the endometrium and respective receptors on the trophoblast may be important.
Leukemia-inhibiting
310
The trophoblast separates into a cellular _________ (closest to inner cell mass) and a multinucleated ___________ (closest to the endometrium).
Cytotrophoblast; Syncytiotrophoblast
311
Syncytiotrophoblast projections penetrate the endometrial basal lamina and then begin to invade the endometrial ______. Trophoblastic lacunae (hollow cavities within the syncytiotrophoblast) appear.
Stroma
312
Eroded endometrial blood vessels fill trophoblastic lacunae with maternal _______. Trophoblast is less invasive at this point.
Blood
313
The _______ _______ is the response of the endometrial stroma cells to the invading blastocyst. Without this, the trophoblast potential might erode all the way through the endometrial wall.
Decidual reaction
314
Decidual cells that participate in the decidual reaction are derived from endometrial stroma cells that accumulate ______ and ______ droplets.
Glycogen; Lipid
315
The result of the decidual reaction is a massive cellular matrix that completely surrounds the embryo and fill most of the endometrium. Infiltrating leukocytes in the endometrium secrete ________, which prevents the mother's immune system from recognizing the embryo as a foreign body.
Interleukin-2
316
A primary function of the decidual reaction is to provide an immunologically privileged site to protect the developing embryo from being...
Rejected
317
54% of ectopic pregnancies (the highest #) are...
Ampullary
318
The initial state of the embryo consisting of two cell layers derived from the inner cell mass are the...
Epiblast
| Hypoblast
319
_______ occurs in humans at the end of the second week of gestation. At this stage, the embryo consists of two flat layers of cells: Epiblast and Hypoblast.
Gastrulation
320
During the third week of gestation, three embryonic layers form from the epiblast, which are...
Ectoderm
Mesoderm
Endoderm
321
Cells entering the inner cells mass earliest express ______ and are destined to become epiblast cells.
Nanog
322
Cells entering the inner cell mass later express ______ and are destined to become hypoblast cells.
Gata 6
323
Gata 6 expression may be induced by _______ secretion from the earlier cells.
FGF-4
324
The epiblast and hypoblast are separated by a...
Basal lamina
325
Epithelial-mesenchymal cell transformation is correlated with expression of transcription factor ______.
Snail
326
Prior to induction, ectoderm expresses both _______ and ______.
E-cadherin; N-CAM
327
After neural tube induction, overly ectoderm only expresses...
E-cadherin
328
After neural tube induction, neural tube ectoderm only expresses...
N-CAM
329
The most important event in gastrulation is ________ movement.
Morphogenetic
330
Primitive node provides the source of cells that will form the _______.
Notochord
331
Cellular precursors of the notochord migrate anteriorly and are then left behind as a rodlike aggregation as the primitive streak regresses. Notochordal cells fuse with flanking endodermal cells and temporarily form a ________ ________.
Neurenteric canal
332
Notochordal cells separate from the ________ and aggregate to form a solid definitive notochord.
Endoderm
333
The notochord is important in the formation of many axial structures, for example the ____ signal.
Shh
334
The notochord induces the overlying ectoderm to convert to neural ectoderm. Transcription factors involved in this are ______ and ______, and signals involved are ______ and ______.
Foxa-2; Goosecoid
| Noggin; Chordin
335
The notochord specifies the identity of certain cells within the early nervous system and transforms certain mesodermal cells of the somites into _______ ______.
Vertebral bodies
336
The notochord stimulates the earliest steps in the development of the ________.
Pancreas
337
The _______ _______ is also referred to as the head organizer and is formed by early cells that pass through the primitive node.
Prechordal plate
338
The prechordal plate is the source of signals such as _____ in the ventral patterning of the forebrain. The source of signals are important for the survival of the neural crest cells that emigrate from the early forebrain.
Shh
339
This signaling molecule is originated in the posterior epiblast and its target are epiblast cells. It induces the expression of Nodal (another signaling molecule).
Wnt3
340
These signaling molecules originate in the anterior hypoblast and their target is Nodal. They block the expression of Nodal in anterior epiblast and confines its expression to the posterior epiblast.
Lefty 1 and Cer 1
341
This signaling molecule originates in epiblast cells and it has multiple targets. It establishes a posterior signaling center which induces the formation of the primitive streak.
Nodal
342
Expression of nodal in the posterior epiblast and blocking of nodal in the anterior epiblast results in the establishment of the _________ axis.
Anteroposterior
343
This term is the process by which a cell or part of an embryo becomes restricted to a given developmental pathway. The point at which a cell becomes committed to a specific cell line.
Determination
344
This term is a complex of changes involved in the progressive specialization of structure and function; often resulting in the formation of luxury molecules.
Differentiation
345
5 examples of body asymmetry are...
```
Heart
Looping of gut
Liver
Spleen
Lung lobation
```
346
The first sign of asymmetry in the body involves the beating of _______ around the primitive node.
Cilia
347
Asymmetrical beating results in a directional current and expression of ______ molecules. This induces ______, which is the symmetry breaking molecules in the left side of the embryo, and _______, which is on the left side of the primitive streak and blocks diffusion of molecules to the right side.
TGF-Beta
Nodal
Lefty-1
348
Asymmetrical current occurs between ____ and ____-somite stage in mouse.
2; 6
349
Put the following stages in neural tube development in order from first to last --
A. Folding of neural plate
B. Shaping of neural plate
C. Formation of thickened neural plate
D. Formation of neural tube
1. C
2. B
3. A
4. D
350
In the formation of a thickened neural plate, there is columnarization of midline ectodermal cells overlying the notochord that involves ________. There is a change in cell adhesion molecules.
Microtubules
351
These pathways are critical in the early shaping of the embryo. They convert elliptical gastrula into keyhole-shaped neural and are important in the folding of the neural plate into the neural tube. In its absence, neural folds remain far apart and tube closure is absent.
Planar cell polarity pathways (PCP)
352
Planar cell polarity is caused by asymmetric distribution of planar cell polarity proteins. The protein concentrated posteriorly is _______ and the proteins concentrated anteriorly is _______.
Disheveled
| Prickle
353
The folding of the neural plate contains a median hinge point induced by the notochord. It involves changes in shape of _______ cells to _______-shaped cells via apical constriction. It requires synthesis of actin filaments at apical ends of cells.
Columnar
| Pyramidal
354
The folding of the neural plate contains lateral hinge points that also involve apical constriction by ______ filaments.
Actin
355
The _______ of neural folds is due to pushing inward by expanding non-neural epithelium.
Elevation
356
The folding of the neural plate results in the formation of the neural _______ flanked by neural folds.
Groove
357
The formations of the neural tube is due to the fusion of apical surfaces of neural ______.
Folds
358
The formation of the neural tube is mediated by...
Glycoconjugates
359
Closure of the neural tube begins midway along the neural tube (21-22 days), and tube closure extends _______ and _______.
Cranially; Caudally
360
In the formation of the neural tube, the anterior and posterior ________ remain at day 23 (will close shortly after).
Neuropore
361
In neural tube segmentation, the anterior neural tube subdivides into the tripartite brain, which includes...
Prosencephalon
Mesencephalon
Rhombencephalon
362
In the tripartite brain, only the prosencephalon and rhombencephalon show segmentation. In the prosencephalon these segments are called _______ and in the rhombencephalon they are called _______ (these are both types of neuromeres).
Prosomeres
| Rhombomeres
363
The tripartite brain will further divide into the pentapartite brain, which includes the...
```
Telencephalon
Diencephalon
Mesencephalon
Metencephalon
Myelencephalon
```
364
In neural tube segmentation, the head organizing region consists of anterior visceral endoderm and prechordal plate. This results in the expression of _____ in the forebrain/midbrain region.
Otx-2
365
In neural tube segmentation, the anterior notochord results in the expression of _____ in hindbrain region.
Gbx-2
366
In neural tube segmentation, the anterior-posterior gradient is established by ______.
Wnt-8
367
In neural tube segmentation, the isthmic organizer has a signaling center established by the boundary between the Otx-2 and Gbx-2. This is important in organizing the midbrain and the cerebellum. It releases _____ anteriorly and _____ posteriorly.
Wnt-1
| FGF-8
368
In neural tube segmentation, the anterior neural ridge signaling center is important in organizing the telencephalon, parts of diencephalon, olfactory area, and pituitary gland. It secretes _____ and _____.
Shh
| FGF-8
369
In neural tube segmentation, the zona limitans signaling center organizes the border between the dorsal and ventral thalamus. It secretes _____.
Shh
370
The human hindbrain is divided into ____ rhombomeres.
7
371
In hindbrain segmentation, rhombomeres r3 and r5 are expressed by ______.
Krox 20
372
In hindbrain segmentation, rhombomere r5 is also expressed by...
Kreisler
| Hoxa-1
373
In hindbrain segmentation, rhombomeres r4-r7 are expressed by...
Retinoic acid
374
In hindbrain segmentation, rhombomeres r1-r3 are expressed by...
Gbx-2
375
The (CRANIAL/CAUDAL) part of the neural plate serves as a stem cell zone. Cells produced in this region as a result of mitotic activity continue to proliferate but do not differentiate as long as they are in this zone.
Caudal
