Chapter 16 and 17 course packet part 2

Question 1

Prenatal period, zygote is

Answer 1

Secondary oocyte, that has only gone through meiosis 1, that is penetrated by a sperm at fertilization

Question 2

What happens once the zygote, which is the secondary oocyte, is penetrated by a sperm?

Answer 2

The cortical granules in the egg cytoplasm release chemicals that make the zone pellucid impentrable to other sperm

Question 3

Once the sperm tail degenerates what happens

Answer 3

The oocyte nucleus completes meiosis 2, the sperms haploid nuclues enlarges & fuses with the egg’s haploid nucleus

Question 4

What is the result once the sperms haploid enlarges and fuses with the egg’s haploid nucleus

Answer 4

The result being a diploid zygote. The individuals karyotype is now established

Question 5

What happens within 24 hours of the zygote period

Answer 5

The first mitosis or cleavage will commence

Question 6

What is morula?

Answer 6

The initial cells divide in perpendicular planes.

Question 7

During the morula stage, by 4 days after fertilization and the 3rd round of cleavage what is there?

Answer 7

16 embryonic cells arranged in a compact ball called a morula

Question 8

Still contained within the zona pellucid, the morula is physically

Answer 8

The same size as the mature ovum;

Question 9

What is the stage that usually reaches the uterus from the oviduct?

Answer 9

The morula stage

Question 10

Different cells (or blastomeres) of the morula have different what

Answer 10

Developmental fates for a particular individual

Question 11

On day 5 the morula begins to show signs of what

Answer 11

Organization. The ball of cells forms a fluid-filled cavity with the bulk of cells to one side

Question 12

What is the organization stage of the morula called

Answer 12

Blastocysts, and ONLY the inner cell mass will become the fetus

Question 13

What stage at 6-7 days implants into the uterine endometrium

Answer 13

The blastocysts stage

Question 14

What is shed prior to implantation

Answer 14

The zona pellucida

Question 15

What occurs between 10-14 days

Answer 15

Complete implantation and the early formation of the extra embryonic membranes (amnion, chorion, and yolk sac)

Question 16

Embryo is what type of stage

Answer 16

The stage which entails all the developlmental steps from 2 weeks after fertilization until the end of the 8th week takes up most of the first trimester

Question 17

What began in the blastocyst stage really gets going in the

Answer 17

Early embryonic stage: Gastrulation

Question 18

What does Gastrulation entail?

Answer 18

It entails the cell divisions, migrations, and rearrangements that produce 3 germ layers

Question 19

What are the 3 germ layers?

Answer 19

1) Endoderm
2) Mesoderm
3) Ectoderm

Question 20

7 Main points from endoderm

Answer 20

1) Epithelia (internal)
2) GI & respiratory tracts
3) Urinary bladder
4) Urethra
5) parts of inner ear
6) Parts of endocrine glands
7) tonsils & liver

Question 21

5 Main points for mesoderm (middle layers)

Answer 21

1) Cartiliage & bone
2) Muscle & connective tissue
3) Spleen
4) Adrenal cortex
5) Excretory & reproductive system

Question 22

6 Main points for the Ectoderm (outermost)

Answer 22

1) Epidermis & its derivatives
2) CNS & PNS
3) Sensory epithelia of eyes, ears & nose
4) Pituitary gland
5) Tooth enamel
6) Adrenal medulla

Question 23

During the embryonic stage, the 3 germ layers split into what

Answer 23

Subpopulations of cells which become the cellular foundations of future organs

Question 24

Where do we find organ formation or organogenesis

Answer 24

As diff. sets of cells become unique in structure & function, both in prescribed patterns & at prescribed times

Question 25

What does the placenta accomplish

Answer 25

Supply of nutrients & O2 to embryo, expulsion of wastes & CO2 from embryo

Question 26

The stage which in tails all the developmental steps from the 9th week until birth (~39 weeks of fertilization)

Answer 26

Fetus stage

Question 27

What is the final stage of development called

Answer 27

Growth and tissue specialization

Question 28

What are the 3 stepwise processes of Growth & tissue specialization

Answer 28

1) 1st-Cell determination
2) 2nd- Cell differentiation
3) 3rd- Morphogenesis (“the beginning of form”)

Question 29

The process of establishing which of several possible developmental paths an embryonic cell can follow. This begins early with the determination of which part of the egg’s cytoplasm a certain blastomere takes up in the morula stage

Answer 29

1st-Cell determination

Question 30

As those blastomeres continue to undergo mitosis, they begin to take on certain specific structures & functions. A specific example can be seen as the mid-line of the embryonic disk becomes the neural tube which will later become the CNS

Answer 30

2nd-Cell differentiation

Question 31

This is a remarkable & complex process by which particular body regions begin to take recognizable form. The neural tube will continue to develop into a recognizable brain & spinal cord (unmistakably human)

Answer 31

3rd-Morphogenesis

Question 32

What does the fetal stage take up most of

Answer 32

the second and third trimesters

Question 33

What are teratogens

Answer 33

Any entity which may cause developmental abnormalities

Question 34

Newborn (neonate) stage

Answer 34

Stage during the 1st 2 weeks after birth

Question 35

Infant stage

Answer 35

Stage from 2 weeks to 15 months after birth

Question 36

Child stage

Answer 36

Stage from infancy to about 12-13 years

Question 37

Pubescent stage

Answer 37

Stage of puberty, when secondary sexual traits develop; girls 10-16 yrs, boys 13-16 yrs

Question 38

Adolescent stage

Answer 38

Stage from onset of puberty until about 3-4 yrs. later; physical, mental, & emotional maturation

Question 39

Adult stage

Answer 39

Starting with early adulthood between 18-25 yrs.; bone formation & growth completion ; changes proceed very slowly afterward

Question 40

Old age stage

Answer 40

Aging (senescence) culminates in general body deterioration