Emryogenesis and Development

Question 1

What is the cortical reaction

Answer 1

after penetration of the sperm through the cell membrane, a release of Ca ions occurs.

Question 2

Why is depolarization important in the cortical reaction

Answer 2

1) prevents fertilization of the ovum by multiple sperm cells
2) increases the metabolic rate of newly formed zygote

Question 3

What is the mechanism behind dizygotic twins

Answer 3

form from fertilization of 2 eggs released during 1 cycle by 2 different sperm.

Question 4

What is the mechanism behind monozygotic twins

Answer 4

a single zygote splits into two.

Question 5

What is the process of rapid mitotic cell divisions in a zygote

Answer 5

cleavage

Question 6

Describe the first cleavage a zygote

Answer 6

creates an embryo, no longer unicellular. several rounds of mitosis occur but the size of the embryo remains unchanged

Question 7

Describe indeterminate cleavage versus Determinant cleavage

Answer 7

determinate cleavage results in cells committed to differentiating

Question 8

Describe a blastula

Answer 8

a fluid filled cavity where cells surround it. The blastula is what implants into the endometrium of the uterus

Question 9

Gastrulation describes the

Answer 9

the generation of the three distinct cell layers or the 3 primary germ layers; occurs in the first 2-3 weeks after fertilization

Question 10

What are the 3 germ layers and what do they give rise to

Answer 10

ectoderm; skin, hair, nails, epithelia of the nose, mouth, the eye, and the nervous system
mesoderm; endothelial cells, all blood cells, musculoskeletal, circulatory, and connective tissue
endoderm; epithelial lining of digestive and respiratory tracts, pancreases, thyroid, bladder,

Question 11

Why are cells with the same genes able to develop into such distinct cells types? the term

Answer 11

selective transcription

Question 12

describe neurulation

Answer 12

the notochord forms. which gives rise to the neural folds, neural groove. These fuse into the neural tube.

Question 13

at the tip of the neural tube are _. and purpose

Answer 13

neural crest cells, which give rise to form the peripheral nervous system.

Question 14

What are teratogens

Answer 14

substances that interfere with development that cause defects or even death of the developing embryo.

Question 15

What is induction and how does it influence development

Answer 15

the process by which nearby cells influence the differentiation of adjacent cells. Ensures proper spatial location and orientation of cells that share a function or have complementary functions

Question 16

What stages are important in cell specialization

Answer 16

specification, determination, and differentiation

Question 17

Specification refers to

Answer 17

When the initial stage where the cell is reversibly designated as a specific cell type

Question 18

Determination refers to

Answer 18

the commitment of a cell to a particular function. irreversible commitment to a cell lineage.

Question 19

What are morphogens

Answer 19

the secretion of specific molecules from nearby cells that cause determination

Question 20

Differentiation refers to

Answer 20

the cell changing the structure, function, or biochemistry to match the cell type.

Question 21

List and describe the different potencies for stem cells

Answer 21

Totipotent= cells with the greatest potency can become any cell type
Pluripotent= can differentiate to any cell except for those found in the placental structures
Multipotent= can differentiate into multiple cell types in a specific group

Question 22

List types of Cell to Cell communication and meaning

Answer 22

Autocrine= signals act on the same cell that secreted the signal
Paracrine= signals act on cells in the local or nearby area
Juxtacrine= signals directly stimulating receptors on an adjacent cell
Endocrine=signals involve secreted hormones that travel through the bloodstream to a distant tissue

Question 23

Importance of PAX6

Answer 23

a growth factor in the ectoderm that promotes development of the lens of the eye

Question 24

What is senescence

Answer 24

biological aging

Question 25

What are some possible causes of aging

Answer 25

shortening telomeres and fewer and less efficient stem cells

Question 26

What is the difference between apoptosis and necrosis

Answer 26

apoptosis is programmed cell death

necrosis is cell death as a result of injury

Question 27

What is the importance of the placenta

Answer 27

organ where nutrient, gas, and waste exchange occurs, also increases immunity. also produces progesteron, estrogen, and human chorionic gonadotropin (hCG)

Question 28

Importance of fetal hemoglobin (HbF); and how it works; compare to adult hemoglobin (Hb A)

Answer 28

enhances the transfer of oxygen from maternal to fetal circulation. Has a greater affinity of oxygen. Hb A has 2 alpha and 2 beta chains; HbF has 2 alpha and 2 gamma chains

Question 29

Arteries versus veins

Answer 29

arteries carry oxygenated blood away from the heart
veins carry deoxygenated blood toward the heart

A for Artery and Away

Question 30

Arteries and veins in the umbilical. oxygenated or deoxygenated

Answer 30

umbilical Arteries carry deoxygenated blood away from the embryo and umbilical veins carry oxygenated toward the fetus

Question 31

What are the 3 fetal shunts? What vessels or heart chambers do they connect? What organ does each shunt bypass

Answer 31

Foramen ovale= connects right atrium to left atrium, bypasses lungs
Ductus arteriosus= connects pulmonary artery to aorta. bypasses lungs
ductus venosus= connects umbilical vein to inferior vena cava, bypasses liver

Question 32

What are key developmental features of the 1st trimester?

Answer 32

organogenesis occurs

Question 33

What are key developmental features of the 2nd trimester?

Answer 33

tremendous growth occurs, movement begins, face starts to form, and digits elongate

Question 34

What are key developmental features of the 3rd trimester?

Answer 34

rapid growth, brain development, transfer of antibodies to the fetus

Question 35

The notochord forms from what germ layer

Answer 35

mesoderm