Bio Ch 42 Flashcards

1
Q

Fertilization

A

union of a sperm and an egg to form a zygote

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2
Q

Development

A

includes all the changes that occur during the life cycle of an organism

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3
Q

Embryo

A

during the early stages of development, an organism is called this

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4
Q

Cleavage

A

cell division without growth

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5
Q

Morula

A

solid ball of cells

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6
Q

Blastula

A

hollow ball of cells having a fluid-filled cavity (blastocoel)

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7
Q

Blastocoel

A

fluid-filled cavity in the blastula

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8
Q

Yolk

A

dense nutrient material in a hard-shelled egg

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9
Q

Gastrulation

A

tissue stages of development involve the formation of a gastrula

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10
Q

Gastrula

A

forms from the blastula; 2 stages - early and late

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11
Q

Ectoderm

A

outer layer of cells

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12
Q

Endoderm

A

inner layer of cells

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13
Q

Blastopore

A

pore/hole created by invagination

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14
Q

Mesoderm

A

in addition to ectoderm and endoderm, the late gastrula has a middle layer of cells called this

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15
Q

Germ layers

A

ectoderm, mesoderm, and endoderm are called the embryonic ____ ______

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16
Q

Notochord

A

newly formed mesoderm cells lie along the main longitudinal axis of the animal and coalesce to form this dorsal supporting rod

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17
Q

Neural plate

A

thickening of cells first seen along the dorsal surface of the embryo

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18
Q

Neural tube

A

neural folds develop on either side of the neural groove, which becomes this when these folds fuse

19
Q

Cellular differentiation

A

occurs when cells become specialized in structure and function

20
Q

Morphogenesis

A

produces the shape and form of the body; one of the earliest indicators is cell movement

21
Q

Pattern formation

A

how tissues and organs are arranged in the body

22
Q

Apoptosis

A

programmed cell death

23
Q

Totipotent

A

having the ability to generate the entire organism, and therefore must contain all the instructions needed by any other specialized cell in the body

24
Q

Maternal determinants

A

egg is known to contain these substances in the cytoplasm which influence the course of development

25
Q

Cytoplasmic segregation

A

parceling out of maternal determinants as mitosis occurs

26
Q

Induction

A

ability of one embryonic tissue to influence the development of another tissue

27
Q

Homeotic genes

A

selector genes that select for segmental identity (dictate which body parts arise from the segments)

28
Q

Homeobox

A

homeotic genes have all been found to share a structural feature called this; a sequence of nucleotides that encodes a 60-amino acid sequence (homeodomain)

29
Q

Homeodomain

A

a 60-amino acid sequence encoded by a homeobox

30
Q

Embryonic development

A

1st part of human development when major organs are formed

31
Q

Extraembryonic membranes

A

membrane that is not a part of the embryo but is necessary to the continued existence and health of the embryo

32
Q

Chorion

A

egg membrane lying next to the shell; carries on gas exchange

33
Q

Amnion

A

egg membrane containing the protective amniotic fluid, which bathes the developing embryo

34
Q

Allantois

A

part of the egg that collects nitrogenous wastes

35
Q

Yolk sac

A

part of the egg that surrounds the remaining yolk, which provides nourishment

36
Q

Blastocyst

A

fluid-filled cavity with a single layer of outer cells (trophoblast), and an inner cell mass

37
Q

Trophoblast

A

single layer of outer cells of a blastocyst that provides nourishment for the embryo

38
Q

Implantation

A

at the end of the 1st week, the embryo begins this process in the wall of the uterus

39
Q

Human Chorionic Gonadotropin (HCG)

A

trophoblast secretes this hormone that is the basis for the pregnancy test and that serves the maintain the corpus luteum past the time it normally disintegrates

40
Q

Embryonic disk

A

inner cell mass has flattened into this during the 2nd week of pregnancy; composed of 2 layers of cells (ectoderm and endoderm); elongates to form the primitive streak

41
Q

Chorionic villi

A

treelike projections of the chorion

42
Q

Umbilical cord

A

connects the developing embryo to the placenta

43
Q

Placenta

A

mammalian structure that functions in gas, nutrient, and waste exchange between embryonic and maternal cardiovascular systems

44
Q

Menopause

A

period in a woman’s life during which the ovarian and uterine cycles cease; usually occurs between ages 45 & 55