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Biol235 Quiz 6 > Chapter 29 > Flashcards

Chapter 29 Flashcards

1
Q

embryo vs fetus

A

fertilization -8 week
vs
9 week - birth

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2
Q

first, second, and third trimester major points

A
  1. all major organs begin to form; most vulnerable stage
  2. organ growth nearly completed; at end, begins to resemble a baby
  3. rapid growth, doubles in weight; organ systems fully functional
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3
Q

Of the ___ million sperm introduced into the vagina, fewer than ___ million reach the cervix of the uterus and only about ___ reach the secondary oocyte. Fertilization normally occurs in the
uterine (fallopian) tube within __ to __ hours after ovulation. Sperm can remain viable for about __ hours after deposition in the vagina, although a secondary oocyte is viable for only about __ hours after ovulation. Thus, pregnancy is most likely to occur if intercourse takes place during a 3-day window—from ___ ____ before ovulation to ___ ____ after ovulation.

A

200
2
200
12
24
48
24
2 days
1 day

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4
Q

_______ in semen are believed to stimulate uterine motility at the time of intercourse and to aid in the movement of sperm through the uterus and into the uterine tube

A

Prostaglandins

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5
Q

Sperm that reach the vicinity of the oocyte within minutes after ejaculation are not capable of fertilizing it until about __ _____ later (and why)

A

7 hours as they undergo capacitation

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6
Q

capacitation (what/when)

A

series of functional changes that cause the sperm’s tail to beat even more vigorously and prepare its plasma membrane (female repro tracts secretions result in the removal of cholesterol, glycoproteins, and proteins from PM around head of sperm) to fuse with the oocyte’s plasma membrane

during 7 hour window of sperm reaching oocyte and before fertilizing

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7
Q

what must sperm penetrate for fertilization to occur

A

corona radiata: granulosa cells
zona pellucida: glycoprotein layer between oocyte/corona radiata

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8
Q

what is/what causes the acrosomal reaction

A

a glycoprotein in the zona pellucida called ZP3, acts as a sperm receptors; binding specific membrane proteins in the sperm head=triggers acrosomal reaction (the release of he contents of the acrosome

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9
Q

what is polyspermy and how is it prevented (fast and slow block)

A

fertilization by more than one sperm

once one sperm penetrates, oocytes PM depolarizes (fast block)
depolarization triggers intracellular release of Ca2+ -> stimulates release secretory vesicles from oocyte -> inactivate ZP3/harden zona pellucida (slow block)

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10
Q

what happens upon sperm entering ovum

A

ovum completes meiosis II = mature eggs and second polar body
male/female pronuclei form = fuse (syngamy) = 2 haploid become diploid = zygote

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11
Q

syngamy

A

fusion of male and female pronuclei to produce single diploid nucleus

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12
Q

Dizygotic (fraternal) twins vs monozygotic (identical) twins

A

two secondary oocytes released and fertilized
vs
one fertilized ovum that splits into two embryos, same genetic material

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13
Q

when does the developing cell split to have monozygotic twins and what normally happens if it is after that

A

before 8 days
after likely results in conjoined twins

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14
Q

After fertilization, rapid mitotic cell divisions of the zygote called cleavage take place. The zygote’s first division begins about __ hours after fertilization and is completed about _ hours later. Each succeeding division takes slightly less time. By the _____ day after fertilization, the second cleavage is completed and there are ____ cells. By
the end of the third day, there are ___ cells. The progressively smaller cells
produced by cleavage are called _______

A

24
6
second
four
16
blastomeres

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15
Q

blastomeres vs morula vs blastocyst

A

progressively smaller cells produced by cleavage
vs
solid sphere of cells formed by blastomeres; has zona pellucida; same size as zygote
vs
At the 32-cell stage, uterine milk enters the morula, collects between the blastomeres, and reorganizes them around a large fluid-filled cavity called the blastocyst cavity=blastocyst

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16
Q

when does blastocyst formation start

A

When the morula enters the uterine cavity on day 4 or 5

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17
Q

what is uterine milk/function

A

glycogen-rich secretion from
the glands of the endometrium of the uterus enters the morula through the zona pellucida
provide nourishment for morula, develop blastocyst

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18
Q

what are the two distinct cell populations that arise during the formation of the blastocyst

A

embryoblast: inner cell mass; develops into embryo
trophoblast: outer superficial layer of
cells that form the spherelike wall of the blastocyst; develops into outer chorionic sac

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19
Q

Around the ____ day after fertilization, the blastocyst “hatches” from the _____ ______ by digesting a hole in it with an enzyme, and then squeezing through the hole. This shedding of the zona pellucida is necessary in order to permit the next step, implantation (attachment) into the vascular, ______ ________ lining of the uterus.

A

fifth
zona pellucida
glandular endometrial

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20
Q

implantation

A

About 6 days after fertilization (2 days freely in uterine cavity), the blastocyst loosely attaches to the endometrium
7 days after fertilization=attach more firmly

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21
Q

Following implantation, the endometrium is known as the
______

A

decidua

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22
Q

decidua basalis vs decidua capsularis vs decidua parietalis

A

portion of endometrium between embryo and stratum basale of uterus, provide glycogen and lipids
vs
portion of the endometrium located between the embryo and the uterine cavity
vs
remaining modified endometrium that lines the noninvolved areas of the rest of the uterus

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23
Q

summary of events in first week of development (5)

A
  1. fertilization: 12-24 h after ovulation
  2. cleavage: first done 30h after ferti
  3. morula: 3-4 d after fertilization
  4. blastocyst: 4.5-5 d after ferti
  5. implantation: 6 d after fertilization
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24
Q

development of trophoblast (when, what, secretes)

A

8 d after fertilization
region between blastocyst and endometrium for two layers that later become the chorion
secretes enzymes to enable blastocyst to penetrate uterine lining and hCG

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25
Q

Peak secretion of hCG occurs about the _____ ____ of pregnancy, at which the placenta is fully developed and produces the ________ and ______ that continue to sustain the pregnancy.

A

ninth week
progesterone
estrogens

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26
Q

Development of the bilaminar embryonic disc

A

8 days after fertilization, cells of embryoblast differentiate into 2 layers
forms amniotic cavity

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27
Q

Development of the Amnion

A

single layer of squamous cells forms a domelike roof above the epiblast cells called the amnion
eventually surrounds the entire embryo and fills with embryonic fluid

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28
Q

Thus, the _____ forms the roof of the amniotic cavity, and the ______ forms the floor

A

amnion
epiblast (part of embryoblast)

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29
Q

blastocyst buries into

A

endometrium and inner 1/3 of myometrium

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30
Q

Development of the Yolk Sac (when, what, 5 function)

A

8 d after fertilization
cells at the edge of the bilaminar embryonic disc migrate and cover the
inner surface of the blastocyst wall

  1. provide nurteints (2-3w)
  2. source of blood cells (3-6w)
  3. contains primidorial germ cells
  4. shock absorber
  5. prevents drying out of embryo
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31
Q

Development of Sinusoids (9d/12d)

A

9 d after fertilization = blastocyst completely embedded in endometrium/lacunae form
12 d = lacunae networks from/endometrial capillaries become dilated = maternal sinusoids

32
Q

Development of the Extraembryonic Coelom

A

12d after fertilization
large number of cavityies from in extraembryonic mesoderm and fuse to form cavity = coelom

33
Q

Development of the Chorion

A

two layers of trophoblasts and extraembryonic mesoderm form chorion
eventually becomes principal embryonic part of placenta

34
Q

two ways chorion protects embryo/fetus from mother’s immune response

A
  1. it secretes proteins that block antibody production by the mother
  2. It promotes the production of T lymphocytes that suppress the normal immune response in the uterus
35
Q
A
36
Q

The inner layer of the chorion eventually fuses with the _____.
With the development of the chorion, the extraembryonic coelom is
now referred to as the _______ ______. By the end of the second week of development, the bilaminar embryonic disc becomes connected to the trophoblast by a band of extraembryonic mesoderm
called the _____ (_____) ____ which is the future ______ _____

A

amnion
chorionic cavity
connecting (body) stalk
umbilical cord

37
Q

gastrulation (when/what)

A

first major event of third week (15d after fetilization)

the bilaminar (two-layered) embryonic
disc transforms into a trilaminar embryonic disc (ectoderm, mesoderm, and endoderm) which are the major embryonic tissues from which the various tissues and organs of the body develop

38
Q

how does gastrulation happen

A

primitive streak (establishes head, tai, R/L sides) and primitive node (at head end, small group of epiblastic cells) form, then invagination due to rearrangement and migration of cells from the epiblast

39
Q

Once the cells have invaginated, some of them displace the hypoblast, forming the ______. Other cells remain between the epiblast and newly formed endoderm to form the ______. Cells remaining in the epiblast
then form the ______. The ectoderm and endoderm are epithelia composed of _____ _____ cells; the mesoderm is a _______ organized connective tissue (mesenchyme)

A

endoderm
mesoderm
ectoderm
tightly packed
loosely

40
Q

endoderm vs mesoderm vs ectoderm form what

A

epithelial lining/gametes
vs
all muscles, blood stuff; mesothelium of cavities, kidneys, adrenal cortex, gonads, dura mater
vs
nervous tissue, hair, epidermis, epithelial lining of more exterior stuff

41
Q

About ___ days after fertilization, mesodermal cells from the primitive node migrate toward the ____ end of the embryo and form a hollow tube of cells in the midline called the ______ _____. By days ______, the notochordal process becomes a solid cylinder of cells called the ______. This structure plays a vital role in ______, the process by which one tissue (inducing tissue) stimulates the development of an adjacent ________ tissue (responding tissue) into a specialized one. The notochord induces certain mesodermal cells to develop into the _______ ______. It also forms the nucleus pulposus of the ______ _____.

A

16
head
notochordal process
22-24
notochord
induction
unspecialized
vertebral bodies
intervertebral discs

42
Q

neurulation

A

late in 3rd week
notochord induces ectodermal cells over it to form the neural plate, elevated edges from neural fold with neural groove between before side attach and form neural tube=develop into brain/SC

43
Q

As the neural tube forms, some of the ectodermal cells from the tube migrate to form several layers of cells called the ______ _____ which forms almost all ______ neurons and ________ neurones

A

neural crest
sensory
postganglionic

44
Q

development of chorionic villi (end of 2nd/3rd week what happens, function)

A

end of 2nd week=chorionic villi develop (fingerlike projections of chorion that project into endometrial wall of uterus)

end of 3rd week=blood capillaries develop in chorionic villi

The fetal blood capillaries within the chorionic villi project into the lacunae, which unite to form the intervillous spaces=help to bring the fetal and maternal blood vessels into
close proximity

45
Q

By the beginning of the _____ week, the placenta has two distinct parts: (1) the fetal portion formed by the ______ ____ of the chorion and (2) the maternal portion formed by the _______ _____ of the endometrium

A

twelfth
chorionic villi
decidua basalis

46
Q

the umbilical cord consists of ____ umbilical arteries that carry deoxygenated fetal blood to the ______, one umbilical vein that carries oxygen and nutrients acquired from the mother’s ______ _____ into the fetus, and supporting mucous connective tissue called _____ ______.

A

two
placenta
intervillous spaces
Wharton’s jelly

47
Q

The fetus is also ____ vulnerable to the damaging effects of drugs, radiation, and microbes than it was as an embryo

A

less

48
Q

For example, during the last 2.5 months of intrauterine life, ____ of the full-term weight is added. At the beginning of the fetal period, the head is ___ the length of the body. By the end of the fetal period, the head size is only ____ the length of the body.
During the same period, the limbs also increase in size from _____ to _____the fetal length

A

half
half
1/4
1/8
1/2

49
Q

embryonic period 1-4 weeks (approximate size, representative changes)

A

0/6 cm

Primary germ layers and notochord develop
Neurulation occurs
Primary brain vesicles, somites, and
intraembryonic coelom develop
Blood vessel formation begins and blood forms in yolk sac, allantois,
and chorion
Heart forms and begins to beat Chorionic villi develop and placental formation begins
The embryo folds
The primitive gut, pharyngeal arches, and limb buds develop
Eyes and ears begin to develop, tail forms, and body systems begin to form

50
Q

embryonic period 5-8 weeks (approximate size/weight, representative changes)

A

3cm/1g

Limbs become distinct and digits appear
Heart becomes four-chambered
Eyes are far apart and eyelids are fused
Nose develops and is flat
Face is more humanlike
Bone formation begins
Blood cells start to form in liver
External genitals begin to differentiate
Tail disappears
Major blood vessels form
Many internal organs continue to develop

51
Q

During the first ____ months of pregnancy, the corpus luteum in the ovary continues to secrete _________ and _______, which maintain the lining of the uterus during pregnancy and prepare the mammary glands to secrete milk. The amounts secreted by the corpus luteum, however, are only slightly more than those produced
after ovulation in a normal menstrual cycle. From the third month
through the remainder of the pregnancy, the _____ itself provides
the high levels of progesterone and estrogens required

A

3-4
progesterone
estrogens
placenta

52
Q

The chorion begins to secrete estrogens after the first _____ weeks
of pregnancy and progesterone by the ____ week.

A

3 or 4
sixth

53
Q

relaxin (produce by/function)

A

produced by corpus luteum and by placenta
increases the flexibility of the pubic symphysis and ligaments of the sacroiliac/sacrococcygeal joints and helps dilate the uterine cervix during labor

54
Q

By the ______ month, when the placenta is fully established, the secretion of ____ is greatly reduced, and the secretions of the corpus luteum are no longer essential. A high level of ______ ensures that the uterine myometrium is relaxed and that the cervix is tightly closed.

A

fourth
hCG
progesterone

55
Q

human chorionic somatomammotropin (hCS) (AKA, produced by, function)

A

AKA human placental lactogen (hPL)

produced by chorion of placenta

thought to help prepare the mammary glands for lactation, enhance maternal growth by increasing protein synthesis, and regulate certain aspects of metabolism in both mother and fetus. For example, hCS decreases the use of glucose by the mother and promotes the release of fatty acids from her adipose tissue, making more
glucose available to the fetus

56
Q

corticotropin-releasing hormone (CRH) (produced by, function, when)

A

produced by the placenta

begins at about 12 weeks and increases enormously toward the end of pregnancy

CRH is now thought to be part
of the “clock” that establishes the timing of birth (higher levels earlier=deliver early)
increases secretion of cortisol, which is needed for maturation of the fetal lungs and the production of surfactant

57
Q

Stroke volume increases by about ___ and cardiac output rises by ____ due to increased maternal ____ ____ to the placenta and increased ______

A

30%
20-30%
blood flow
metabolism

58
Q

Heart rate increases _____ and blood volume increases ______, mostly during the ______ _____ of pregnancy.

A

10–15%
30–50%
second half

59
Q

Tidal volume can increase by
_____, expiratory reserve volume can be reduced by up to ___, functional residual capacity can decline by up to ____, minute ventilation (the total volume of air inhaled and exhaled each minute) can increase by up to ___, airway resistance in the bronchial tree can decline by _____, and total body oxygen consumption can increase by
about _____.

A

30-40%
40%
25%
40%
30–40%
10–20%

60
Q

An increase in renal plasma flow up to ___ and an increase in glomerular filtration rate up to ___ increase the renal filtering capacity, which allows faster elimination of the extra wastes produced by the fetus

A

35%
40%

61
Q

the uterus increase from its non[regnant mass of _____ to _____

A

60-80g
900-1200g

62
Q

partuition

A

labor

63
Q

true vs false labor

A

begins when uterine contractions occur at regular intervals, usually producing pain; back pain intensified by walking; dilation of cervix; show of discharge of blood containing mucus at cervical canal
vs
pain is felt in the abdomen at irregular intervals, but it does not intensify and walking does not alter it significantly. There is no “show”/cervical dilation

64
Q

true labor three stages

A
  1. stage of dilation: onset to complete dilation; 6-12h, amniotic sac ruptures
  2. stage of expulsion: dilation to deliver; 10m to several hours
  3. placental stage: after deliver to expulsion of placenta; 5-30m
65
Q

As a rule, labor lasts longer with first babies, typically about __ hours. For women who have previously given birth, the average duration of labor is about __ hours

A

14
8

66
Q

puerperium

A

6-week period after delivery baby where maternal reproductive organs and physiology return to prepregnancy state

67
Q

involution

A

uterus reduces in size due to tissue catabolism

68
Q

lochia

A

discharge of blood/serous fluid for 2-4 weeks after delivery

69
Q

what stimulates baby to breath/cry

A

A rising CO2 level stimulates the respiratory center in the medulla oblongata, causing the respiratory muscles to contract, and the baby to draw their first breath. Because the first inspiration is unusually deep, as the lungs contain no air, the baby also exhales vigorously and naturally cries

70
Q

The production of surfactant begins by the end of the _____ month of development

A

sixth

71
Q

A full-term baby may breathe ___ times a minute for the first __ weeks after birth. Breathing rate gradually declines until it approaches a normal rate of ___ breaths per minute

A

45
2
12

72
Q

At birth, an infant’s pulse may range from ___ to ___ bpm and may go as high as ____ on excitation

A

120 to 160
180

73
Q

cardiovascular changes of infant upon birth

A
  1. closure of foramen ovale=deoxygenated blood can enter lungs
  2. ductus arteriosus shuts off
  3. umbilical cord fills with CT
  4. ductus venosus collapses=blood can enter liver
74
Q

prolactin vs oxytocin

A

stimulates milk production vs stimulates milk release

75
Q

oxytocin stimulates contraction
of _______ (smooth muscle–like) cells surrounding the _____ cells and ducts. The resulting compression moves the milk from the _____ of the mammary glands into the mammary ducts, where it can be suckled. This process is termed ______ _______

A

myoepithelial
glandular
alveoli
milk ejection

76
Q

colostrum

A

cloudy fluid secreted in late pregnancy and first days after birth
not as nutritious as milk—it contains less lactose and virtually no fat—
colostrum serves adequately until the appearance of true milk on
about the fourth day

77
Q
A

Biol235 Quiz 6 (5 decks)

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