Chapter 12

Question 1

Mitosis

Answer 1

cell division with 46 chromosomes in each cell—In all cells but the gamete cells

Question 2

Meiosis

Answer 2

cell division of the gamete cells with 23 chromosomes in each cell —- Spermatogenesis & oogensis so that the fertilized ovum will have a complete compliment of chromosomes (23 + 23= 46)

Question 3

gamete cells

Answer 3

reproductive cells - sperm and ovum (each 23)

Question 4

spermatogenesis

Answer 4

process of developing mature sperm

Question 5

oogensis

Answer 5

split and resplit until mature ovum

Question 6

autosomes

Answer 6

chromosomes that don’t deal with the sex of the child

Question 7

who determines the sex of the child

Answer 7

the male

Question 8

end up with ___ sperm capable of

Answer 8

4 sperm capable of fertilizing mature ovum

Question 9

the ovum will not divide into truly mature ovum unless

Answer 9

fertilized by sperm

Question 10

ovum

Answer 10

Relatively large cell that can be seen with the naked eye

Chromosomes in the ovum

Question 11

Spermatoza

Answer 11

Overall length is ¼ that of the ovum
Travels at the rate of 1cm in 3 mins.-active swimming movements- can reach cervix in 90 seconds and fallopian tube in 3 days
Capable of fertilizing an ovum for up to 3 days
Determines the sex of the child
The head of the sperm has a covering layer that secretes an enzyme called Hyaluronidase (enzyme that helps with penetration of the ovum, also will help let other sperm penetrate the ovum)
Fertilizes the ovum usually in the outer third of the tube

Question 12

mature human sperm

Answer 12

once sperm penetrates ovum looses tail

200-500 million sperm release in ejaculation, released in 1 teaspoon of fluid

Question 13

conception

Answer 13

• Requires correct timing between the release of a mature ovum and
• Ejaculation of enough healthy, mature sperm into the vagina.
• Ovum usually lives no longer than 24 hours after oogenesis

Question 14

Fertilization

Answer 14

• The method by which the spermatozoa penetrates the ovum
• The enzyme (hyaluronidase) causes the zona pellucida to be penetrated
• This prevents other sperm from entering
• The ovum, in the 2nd stage of meiotic division, now completes meiosis and becomes a mature ovum
• The sperm goes through the membrane and loses its’ tail
• The nucleus of the sperm and ovum unite and cell division begins

Question 15

progression of cell division

Answer 15

• The union of the sperm and ovum produces a structure called the ZYGOTE, and with cell division each cell will have 46 chromosomes
• Cell division is now by mitosis and the rapid cell division is called cleavge (everytime cell division occurs)
• This structure continues to move through the fallopian BUT the size of the structure - remains the same (if it got bigger and bigger wouldn’t make it up the fallopian tube)
• Each separate cell during this division is called a BLASTOMERE
• When the structure has 16 cells it is called a MORULA -at 60-72 hrs. after fertilization 16 cells

Question 16

blastocyst

Answer 16

The morula enters the uterus approx. 3-4 days after conception and at this point has approx. 100 cells and is now called a BLASTOCYST and remains in the uterus for 2-4 days before implantation
Inner cells of the structure will become the embryo- EMBRYOBLAST
The outer cells will become the placenta and fetal membranes-TROPHOBLAST

Question 17

trophoblast

Answer 17

The trophoblast (part of the blastocyst) embeds into the endometrial tissue (shed during mensis)
   (now called the DECIDUA -capsularis, basalis,vera) 
NIDATION: the process of implantation of the fertilized ovum into the decidua
It divides into 2 distinct layers which will become the placenta and fetal membranes (Chorion)

Question 18

decidua basalis -

Answer 18

where it beds into tissue

Question 19

decidua capsularis -

Answer 19

covers front of structure

Question 20

decidua vera -

Answer 20

anything else not in contact with it

Question 21

embryoblast

Answer 21

A compact inner layer of cells from which the embryo will develop

Question 22

Changes occur within the embryoblast and the cells form:

Answer 22

1. Amniotic cavity- that will gradually grow and encircle the developing fetus
   
   2. Yolk Sac–that will feed the embryo
   3. Embryonic disc–from which the fetus will develop

Question 23

yolk sac -

Answer 23

feeds cells until placenta takes over

Question 24

all body parts and systems develop from

Answer 24

embryonic disk

Question 25

if deformity look at all three layers which are

Answer 25

amniotic, yolk sac, embryonic disk

Question 26

embryonic disk three layers

Answer 26

1. ENDODERM: lining of GI and Resp. tracts, thyroid, liver, pancreas
   
   2. ECTODERM: brain and spinal cord, pituitary gland, hair, mammary glands, tooth enamel
   3. MESODERM: bone, muscle tissue, ovaries/testes, heart, spleen

Question 27

after about the 3rd week after fertilization form

Answer 27

layers fo embryonic disk

Question 28

stages of development

Answer 28

pre embryonic stage, embryonic stage, fetal stage

Question 29

pre embryonic stage

Answer 29

the first 14 days from conception until the primary villa appear

Question 30

embryonic stage

Answer 30

the beginning of the 3rd week until end of the 8th week, all body systems are established by the end of this stage

Question 31

fetal stage

Answer 31

the beginning of the 9th week until delivery

Question 32

when are all structures and systems formed? **

Answer 32

end of 3 months (12 weeks)

Question 33

will not see birth defects until

Answer 33

3rd week (week 8 most concerned)

Question 34

most dangerous stage of development

Answer 34

embryonic stage

Question 35

can determine gestational age with

Answer 35

crown-rump length