Biology Chapter 3: Embryogenesis and Development (2 Stars)

Question 1

______ is the joining of a sperm and an ovum.

Answer 1

Fertilization

Question 2

Where does fertilization take place?

Answer 2

It usually occurs in the ampulla of the fallopian tube.

Question 3

The sperm uses _______ enzymes to penetrate the corona radiata and zona pellucida.

Answer 3

acrosomal

Question 4

Once it contacts the oocyte’s plasma membrane, the sperm establishes the acrosomal apparatus and injects its _________

Answer 4

pronucleus

Question 5

When the first sperm penetrates, it causes a release of ________, which prevents additional sperm from fertilizing the egg and increases the metabolic rate of the resulting diploid zygote. This is called the cortical reaction.

Answer 5

calcium ions

Question 6

Fraternal (dizygotic) twins result from the fertilization of two eggs by ________ sperm. Identical (monozygotic) twins result from the splitting of a _____in two. Monozygotic twins can be classified by the placental structures they share (mono- vs. diamniotic, mono- vs. dichorionic).

Answer 6

two different

zygote

Question 7

______ is defined as the early divisions of cells in the embryo. These mitotic divisions result in a larger number of smaller cells, as the overall volume does not change.

Answer 7

Cleavage

Question 8

The ______ becomes an embryo after the first cleavage because it is no longer unicellular.

Answer 8

zygote

Question 9

________ cleavage results in cells that are capable of becoming any cell in the organism, while determinate cleavage results in cells that are committed to differentiating into a _______ cell type.

Answer 9

Indeterminate

specific

Question 10

The ________ is a solid mass of cells seen in early development.

Answer 10

morula

Question 11

The ________ has a fluid-filled center has two different cell types, including trophoblasts (which become placental structures) and the inner cell mass (which becomes the developing organism).

Answer 11

blastula (blastocyst)

Question 12

The blastula implants in the _______ and forms the placenta.

Answer 12

endometrial lining

Question 13

The chorion contains chorionic villi, which penetrate the endometrium and create the interface between ______ and ______blood.

Answer 13

maternal

fetal blood.

Question 14

Before the placenta is established, the embryo is supported by the ______.

Answer 14

yolk sac.

Question 15

The ________ is involved in early fluid exchange between the embryo and the yolk sac.

Answer 15

allantois

Question 16

The amnion lies just inside the _______ and produces amniotic fluid.

Answer 16

chorion

Question 17

The developing organism is connected to the ______ via the umbilical cord.

Answer 17

placenta

Question 18

During gastrulation, the archenteron is formed with a blastopore at the end. As the archenteron grows through the blastocoel, it contacts the opposite side, establishing three primary ______ layers.

Answer 18

germ layers

Question 19

The ________ becomes epidermis, hair, nails, and the epithelia of the nose, mouth, and anal canal, as well as the nervous system (including adrenal medulla) and lens of the eye.

Answer 19

ectoderm

Question 20

The __________ becomes much of the the musculoskeletal, circulatory, and excretory systems.

Answer 20

mesoderm.
Also gives rise to the gonads and the muscular and connective tissue layers of the digestive and respiratory systems, as well as the adrenal cortex.

Question 21

The ________ becomes much of the epithelial linings of the respiratory and digestive tracts, and parts of the pancreas, thyroid, bladder, and distal urinary tracts.

Answer 21

endoderm

Question 22

Neurulation, or development of the nervous system, begins after the formation of the # ____ germ layers.

Answer 22

3 germ layers.

Question 23

The notochord induces a group of overlying _____cells to form neural folds surrounding a neural groove.

Answer 23

ectodermal

Question 24

The neural folds fuse to form the neural tube, which becomes the __________.

Answer 24

central nervous system.

Question 25

The tip of each neural fold contains neural crest cells, which become the ________ (sensory ganglia, autonomic ganglia, adrenal medulla, and Schwann cells) as well as specific cell types in other tissues (calcitonin-producing cells of the thyroid, melanocytes in the skin, and others).

Answer 25

peripheral nervous system

Question 26

_______ are substances that interfere with development, causing defects or even death of the developing embryo.

Answer 26

Teratogens

include alcohol, certain prescription drugs, viruses, bacteria, and environmental chemicals.

Question 27

________ occurs as a result of determination and differentiation.

Answer 27

Cell specialization

Question 28

________ is the commitment to a specific cell lineage, which may be accomplished by uneven segregation of cellular material during mitosis or by morphogens, which promote development down a specific cell line.

Answer 28

Determination

To respond to a specific morphogen, a cell must have competency.

Question 29

Differentiation refers to the changes a cell undergoes due to __________ to take on characteristics appropriate to its cell line.

Answer 29

selective transcription

Question 30

______are cells that are capable of developing into various cell types.

Answer 30

Stem cells

Question 31

______ cells are able to differentiate into all cell types, including the three germ layers and placental structures.

Answer 31

Totipotent

Question 32

_______ cells are able to differentiate into all three of the germ layers and their derivatives.

Answer 32

Pluripotent

Question 33

Multipotent cells are able to differentiate _________

Answer 33

only into a specific subset of cell types.

Question 34

Cells communicate through a number of different signaling methods. An inducer ______ factors to promote the differentiation of a competent responder.

Answer 34

releases

Question 35

______ signals act on the same cell that released the signal.

Answer 35

Autocrine

Question 36

_______ signals act on cells in the local area.

Answer 36

Paracrine

Question 37

Juxtacrine signals act through

Answer 37

direct stimulation of the adjacent cells.

Question 38

Endocrine signals act on ______ tissues after traveling through the bloodstream.

Answer 38

distant

Question 39

If two tissues both induce further differentiation in each other, this is termed _________

Answer 39

reciprocal induction.

Question 40

Signaling often occurs via ________.

Answer 40

gradients.

Question 41

Apoptosis is__________ via the formation of apoptotic blebs that can subsequently be absorbed and digested by other cells.

Answer 41

programmed cell death

Apoptosis can be used for sculpting certain anatomical structures, such as removing the webbing between digits.

Question 42

_________ capacity is the ability of an organism to regrow certain parts of the body.

Answer 42

Regenerative

The liver has high regenerative capacity, while the heart has low regenerative capacity.

Question 43

_______ is the result of multiple molecular and metabolic processes; most notably, the shortening of telomeres during cell division.

Answer 43

Senescence

Question 44

Nutrient, gas, and waste exchange occurs at the _______

Answer 44

placenta

Question 45

Oxygen and carbon dioxide are _______ exchanged due to concentration gradients.

Answer 45

passively

Question 46

Fetal hemoglobin (HbF) has a ______ affinity for oxygen than adult hemoglobin (primarily HbA), which also assists in the transfer (and retention) of oxygen into the fetal circulatory system.

Answer 46

higher

Question 47

The placental barrier also serves as_______ against many pathogens, and antibodies are transferred from mother to child.

Answer 47

immune protection

Question 48

The placenta serves ______ functions, secreting estrogen, progesterone, and human chorionic gonadotropin (hCG).

Answer 48

endocrine

Question 49

The umbilical arteries carry ___________ blood from the fetus to the placenta; the umbilical vein carries __________ blood from the placenta back to the fetus.

Answer 49

deoxygenated

oxygenated

Question 50

The ________ connects the right atrium to the left atrium, bypassing the lungs.

Answer 50

foramen ovale

Question 51

The ductus arteriosus connects the _______ to the aorta, bypassing the lungs.

Answer 51

pulmonary artery

Question 52

The ductus venosus connects the _______ to the inferior vena cava, bypassing the liver.

Answer 52

umbilical vein

Question 53

In the first trimester, _______ occurs (development of heart, eyes, gonads, limbs, liver, brain).

Answer 53

organogenesis

Question 54

In the _______ trimester, tremendous growth occurs, movement begins, the face becomes distinctly human, and the digits elongate.

Answer 54

second

Question 55

In the third trimester, rapid growth and brain development continue, and there is transfer of ______to the fetus.

Answer 55

antibodies

Question 56

During birth, the cervix ____ out and the amniotic sac ruptures.

Answer 56

thins
Then, uterine contractions, coordinated by prostaglandins and oxytocin, result in birth of the fetus. Finally, the placenta and umbilical cord are expelled.