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Flashcards in Chapter 23 Deck (88):
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Name a fact about blastomeres

Blastomere is an early cell type that divides by cleavage

1

What is the first to develop in a fetus

Morula

the morula is the early ball of cells that will become the blastocyst

2

Three facts about implantation

Involves a blastocyst the preembryo which implants
Has cells that produce HCG
Occurs by the sixth day

3

In the process of in vitro fertilization, the woman is given ? To induce follicle development

Human menopausal gonadotropin

HMG or related compounds will stimulate the ovary to produce follicles; HCG is then used to induce ovulation

4

The main factor that may NOT allow a 24 week fetus to survive independently is the

Surfactant

Surfactant is the lipid in the lungs that prevents collapse and allows the fetus to breathe; premature infants often lack this ability and must be sustained artificially until their surfactant is sufficient

5

The ductus venosus transports blood to the ?

Vena cava

The umbilical vein becomes the ductus venosus

6

The foramen ovale allows blood from the right atrium to enter the

Left atrium

7

Large amounts of blood do NOT enter r fetal lungs because their

Resistance is high

The resistance to blood flow in the fetal lungs is higher than the right ventricle blood flow pressure which cannot overcome the resistance to any great extent

8

The ductus arteriosclerosis allows blood to flow from the pulmonary trunk to the

Aorta

The ductus arteriosus is a shunt lung bypass between the pulmonary trunk and the aorta

9

What vessel transports blood rich in oxygen and nutrients to the fetus

Umbilical vein

The umbilical vain travels toward the heart of the fetus and is thus a vein; however it is coming from the placenta where it picked up oxygen and nutrients.

10

With in the fetus, much of the circulating blood bypasses the lungs and flow through the

Ductus arteriosus

The arteriosus shunts blood from the pulmonary trunk to the aorta

11

The period immediately after birth to four weeks of age is called the ? Period

Neonatal

The first month of extrauterine life in the neonatal period

12

Many changes occur in the newborn infant as it adapts to a life apart from its mother. What happens to the umbilical vein?

It closes off to become the ligamentum teres.

The umbilical vein remains as a ligament attached to the liver

13

What is the biological definition of human adulthood

Adolescence to old age

An adolescent is reproductively mature, and therefore is considered an adult

14

In which process do the cells become progressively smaller

Cleavage

Cell division takes place so rapidly during cleavage that the cells do not grow between divisions

15

When is a developing individual most susceptible to genetic birth defects from smoking

First trimester

The first trimester is the most critical time period in all of development

16

When is it possible to distinguish the sex of the fetus

Third month

The sex of the fetus begins differentiation around week 8 or 9

17

When does bone start to replace cartilage

Third month

Endochondral ossification and intramembranous ossification begin around week 10

18

The embryonic period lasts from the second week through ? Week

Eighth

The embryonic period begins when two distinct cell layers form and proceeds until around the eighth week when differentiation ends

19

Name 3 things that arise from the mesoderm

Muscle
Kidney
Blood

20

What prevents the maternal and embryonic blood cells from mixing

Placental membrane

The placental membrane is a layer of epithelial cells that separate the villi from the maternal endometrium

21

When will the embryo take on a human appearance

Eighth week

Human structures become evident and differentiated by the eighth week, prior to this time the embryo passes through. Stages that seem to resemble other mammals

22

Name 3 fetal component

Chlorion
Amnion
Umbilical cord

23

Of every 100 secondary oocytes that are exposed to sperm, how many infants are actually born alive

About 31

24

When does the amnion first appear

Second week

The rudimentary amnion appears in the second week and becomes fluid filled

25

What is the origin of fetal blood cells

Yolk sac

The yolk sac appears in the second week and is the origin of the fetal blood cells and gametes that will migrate into the fetus

26

What is the major cell process in the fetus

Mitosis

Differentiation has ended with the onset of the fetus and all growth processes are mitotic in nature

27

When can the male and female organs be distinguished first

Twelfth week

By the twelfth week the external genitalia are distinguishable

28

Name 3 things true at full term

Fingernail are present
Vertex position is evident
Fetus is 50 cm long

The testes begin to descend around the eight month but may not be completed until after birth

29

The umbilical arteries are branches of the

Internal iliac arteries

30

What has the greatest oxygen content in a fetus

Umbilical vein

Umbilical Arteries are traveling to the placenta to gain oxygen from the mother

31

What system function is most critical in the neonate

Respiratory

During the first month of life, the exchange of gasses is critical, the liver is one of the last organs to mature

32

Name 3 factors that causes the first breath of life

Blood pH
Carbon dioxide
Low blood oxygen

The initiation of breathing occurs from stimulation of the brain stem, epinephrine is produced and rises because of the stress of delivery and is important for increasing the ability of the lungs to expand

33

In the first days of life, what is the primary source of energy

Lipid

34

The superior vesical arteries are remnants of the

Umbilical arteries

A portion of the umbilical arteries persist in the neonate as the superior vesical arteries that supply blood to the bladder

35

The ligament teres is the remnant of the

Umbilical vein

The ligamentum teres Is the fibrotic degeneration of the umbilical vein from the umbilicus to the liver

36

The ligamentum venosum is the remnant of the

Ductus venosus

The ductus venosus in the liver atrophies into the closed ligamentum venosum

37

The reason why blood no longer passes through the foremen ovale is initially explained by the

Increase in left atrial pressure

The increase in left atrial pressure during inspiration causes the septum primum valve to close the foremen ovale

38

The constriction of the ductus arteriosus is related most likely to

Bradykinin

39

At what age is most hemoglobin of the adult type

At four months

40

After age 30, the adult loses about ? % of their functional capacity each year

.8

It is estimated that degeneration occurs after age 30 when about .8% of their functional capabilities is lost each successive year

41

The chemical theory of aging involves the formation of

Free radicals

42

The premature separation of the placenta is

Abruptio placentae

43

Perinatology is a branch of medicine that studies the

Fetus and neonate

The domain of perinatology is the 24 week fetus through first four weeks after birth

44

Name 3 things that freely cross the placental membrane

Leukocytes
Glucose
NaCl

NOT erythrocytes. Leukocytes wander anywhere by diapedesis and chemotaxis

45

Epithelial lining of the digestive tract , respiratory tract and urethra all form from the ? Layer of the gastrula

Endoderm

Lining of passageways with an external connection come from endoderm

46

The portion of the placenta contributed by the embryo is the

Chorion

47

Within which embryonic membrane are blood cells formed in the early stages of development

Yolk sac

First blood cells come from yolk sac

48

At what age do age related degenerative changes begin in most adults

Age 30

"Aging" begins around 30

49

Name 3 things that aging appears to result from

Genetics
Apoptosis
Accumulation of free-radicals

50

What is the major cause of death in less-developed countries

Infections

51

In which menstrual cycle phase does implantation occur

Secretory

Implantation occurs after ovulation which means the uterus is inits secretory stage

52

What normally prevents the expulsion of an embryo by a menstrual flow

HCG

HCG causes the corpus luteum to remain, which in turn secretes progesterone thus preventing menses

53

The structure which implants in the endometrium is correctly termed a

Blastocyst

54

When can the term fetus be correctly used

When body systems have been established

55

What extra embryonic membrane encloses the embryo in a fluid filled cavity

Amnion

56

What membrane plays the greatest role in nutrient and waste exchanges

Chorion

Chorion is part of the placenta

57

What hormone prevents a second pregnancy during gestation

Progesterone

58

A sudden increase. In uterine size could indicate the development of a hydatid mole

T or F

True

A hydatid mole or cyst is an abnormal growth of chorionic tissue that might be extensive enough to replace the fetus and even mimic pregnancy

59

The ossification of the skull is completed by full term

T or F

False

Although much of the skull is ossified, it will not become complete until several months after birth

60

Fetal hemoglobin is different from the adult and has a higher oxygen capacity

T or F

True

The hemoglobin of the fetus has a 50% greater oxygen affinity than the maternal blood which favors fetal uptake

61

All the fetal veins contain deoxygenated blood

T or F

False

The ductus venosus contains highly oxygenated blood from the placenta

62

Because of the ductus arteriosus, greater amounts of oxygenated blood can travel to the brain

T or F

False

The ductus arteriosus is connected is connected to the descending portion of the aortic arch past the branching of the arteries that convey blood to the brain

63

The number of umbilical arteries is directly related to the structure of the fetal internal circulatory system

T or F

True

There is a strong correlation between umbilical arteries and fetal circulation, many heart and vessel defects are associated with having only one artery, which is why the umbilical vessels are counted at birth

64

Infant respiratory distress syndrome is less common if the mother had normal labor and delivery

T or F

True

The contractions of the uterus seem to increase the fetal ability to secrete surfactant, babies taken by cesarean delivery may have a higher incidence of respiratory distress syndrome

65

The kidneys of a neonate are immature and therefore do not excrete large amounts of water

T or F

False

The kidneys are immature and do not excrete large amounts of electrolytes and thus produce a dilute urine increasing the chances for dehydration

66

The fossa ovalis is the depression in the heart that was the foramen ovale

T or F

True

The foramen ovale closes shortly after birth and becomes a solid depression called fossa ovalis

67

The ligamentum arteriosum forms in the neonate as a remnant of the ductus arteriosus

T or F

False

The process of scar formation in the replacement of the ductus arteriosus require several months to complete, the term ligamentum arteriosum is more appropriate in an adult heart

68

Heart failure is a common form of death in the first neonatal month

T or F

True

Failure of the ductus arteriosus to collapse will result in a deficiency of oxygen to the heart relative to a high demand

69

Childhood typically ends when the person is six years of age

T or F

False

Childhood is a period from one year to the time of puberty and is therefore variable, but usually falls between one year and around 11 years

70

The average female has a shorter adolescent period than males

T or F

True

The attainment do sexual and physical maturity occurs sooner in females, who usually attain puberty earlier

71

Females are taller and stronger than males when they are both in early adolescence

T or F

True

Females reach a peak earlier than males, but males develop a growth spurt in late adolescence that causes them to exceed females size and strength

72

Older persons require fewer calories and can survive well on smaller portions of food

T or F

False

Older persons require less calories but still require an adequate intake of vitamins, minerals and other essential nutrients which may not be present in a typical small portion of food

73

Older persons have a reduced capacity to prevent infection

T or F

True

The immune system slowly degenerates along with others causing a reduction in the ability to produce antibodies and phagocytic cells

74

Senescence usually ends in death because of neurological changes and degeneration

T or F

False

Death usually results from failures and degenerative changes in the cardiovascular system, a person may have brain death but still remain alive

75

The human life span and life expectancy have both increased in the last one thousand years

T or F

False

Although the life expectancy has generally increased for the total population because of technology and medical care, the theoretical point of death has not increased

76

Collagen synthesis decreases with age and the collagen molecules become soft and degenerated

T or F

False

The collagen fibers actually form cross- links and become stiffer and less flexible, contributing to the dysfunctions seen in the elderly

77

Exposure to sunlight and other forms of radiation may increase the rate of aging

T or F

True

The rate of aging is influenced by the speed of DNA mutation formation, radiation increases the probability of mistakes in DNA synthesis that lead to cancer or aging

78

Within 6 days following fertilization, the blastocyst contains cells that are fated to become the infant

T or F

True

Within six days, the process of differentiation has resulted in the inner cell mass which will develop into the human embryo

79

Dizygotic twins share same placenta and are indentical.

T or F

False

Dizygotic twins result from the separate fertilization of two oocytes and are not identical (fraternal twins) monozygotic twins resulted from a single egg and are identical.

80

The study of abnormal fetal development is teratology

T or F

True

Many factors could cause birth defects and deformities, the study of these is called teratology.

81

The umbilical cord contains maternal and fetal components

T or F

False

The umbilical cord is derived from the embryonic stalk, but the placenta has both maternal and fetal components

82

Amniocentesis is a technique for examining the genetics of fetal skin cells

T or F

True

In amniocentesis, a needle is inserted into the amniotic cavity and fluid withdrawn, the fluid generally contains cells that have been sloughed off and can be used for microscopic and genetic studies to screen for possible defects

83

Postpartum meconium refers to the discharge of fluid from the skin or lungs

T or F

False

Meconium is the first fecal discharge of a newborn before food or milk has been ingested

84

The amount of elastic fibers increases during the aging process causing the lung tissue to regress and constrict

T or F

False

In aging, the amount of elastic tissue in the lungs decreases making it more difficult to exhale, from loss of elastic recoil

85

The cardiovascular system increases the synthesis of some lipids during the aging process.

T or F

True

The coronary artery lumens are decreased by the addition and synthesis of cholesterol-laden plaques made by the artery

86

The placenta is comprised of maternal and fetal portions

T or F

True

The fetal chorion and the maternal endometrium combine to form the placenta

87

The inner cell mass of the blastocyst will become the extra embryonic membranes and part of placenta

T or F

False

The ICM becomes the embryo proper