Chapter 29- Pregnancy & Human Development

Question 1

Fertilization occurs in the ______ _____ about 12 -24 hours after ovulation. However, before fertilization can occur, the sperm must undergo _________ and the _______ _______

Answer 1

Fertilization occurs in the fallopian tube about 12 -24 hours after ovulation. However, before fertilization can occur, the sperm must undergo CAPACITATION and the ACROSOMAL REACTION.

Question 2

Capacitation

Answer 2

weakening of the sperm/acrosome membrane, allowing for later fusion with a secondary oocyte

Question 3

Acrosomal reaction: The sperm will surround the ovulated oocyte in the female and ______ _______from their acrosomes, mostly ________ When this occurs, disruption of the ______ ______ and the ____ _______ will follow. This release occurs from many of the sperm that surround the oocyte in the fallopian tube and will allow the entrance of only one of the sperm.

Answer 3

: The sperm will surround the ovulated oocyte in the female and release enzymes from their acrosomes, mostly HYALURONIDASE. When this occurs, disruption of the CORONA RADIATA. and the ZONA PELLUCIDA will follow. This release occurs from many of the sperm that surround the oocyte in the fallopian tube, and will allow the entrance of only one of the sperm.

Question 4

Zygote is

Answer 4

the end result of fertilization

Question 5

A zygote has

Answer 5

46 chromosomes and is 1 cell

Question 6

Immediately when the sperm enters the secondary oocyte, there are changes in the structure and location of the “veils”, blocking the entrance of more sperm. Therefore, this reaction blocks ______.

Answer 6

Polyspermy

Question 7

How many sperm are required for fertilization?

Answer 7

Thousands
(one will make it through)

Question 8

What fuses together to form a zygote?

Answer 8

A male pronucleus and female pronucleus

Question 9

Morula

Answer 9

A ball of cells in the fallopian tube

Question 10

Usually, a woman ovulates 1 oocyte per month. However, some may ovulate 2. If both are fertilized, ________ _______ (________) result. They are no more genetically alike than any other siblings.

Answer 10

Usually, a woman ovulates 1 oocyte per month. However, some may ovulate 2. If both are fertilized, DIZYGOTIC TWINS ( FRATERNAL TWINS) result. They are no more genetically alike than any other siblings.

Question 11

Zygote –>

Answer 11

Zygote –> Morula –> Blastocyst –> Embryoblast –> Trophoblast –> Blastocoele

Question 12

What stage enters the uterus?

Answer 12

Blasocyst

Question 13

Embryoblast

Answer 13

where the embryo comes from

Question 14

Trophoblast

Answer 14

where the placenta comes from

Question 15

Blastocoele

Answer 15

fluid filled pocket

Question 16

When is implantation?

Answer 16

Around day 23

Question 17

How long do spermatozoa survive?

Answer 17

5-7 days

Question 18

How long is the oocyte viable once ovulated?

Answer 18

24 hours

Question 19

Where does fertilization occur?

Answer 19

In the fallopian tube

Question 20

Identical twins are called

Answer 20

Monozygotic twins

Question 21

Monozygotic twins:
This occurs when __ oocyte is fertilized by __ sperm, but during development 2 areas of the inner cell mass develop _______. Or there is a separation of _______ into 2 groups of cells. This results in 2 genetically identical individuals. Both must be either be male or female.

Answer 21

This occurs when 1 oocyte is fertilized by 1 sperm, but during development 2 areas of the inner cell mass develop individually. Or there is a separation of blastomeres into 2 groups of cells. This results in 2 genetically identical individuals. Both must be either be male or female.

Question 22

Conjoined twins

Answer 22

Monozygotic twins that are physically joined, due to abnormal cleavage

Question 23

Dizygotic twins are

Answer 23

2 separate oocytes that both get fertilized from different spermatozoa

Question 24

The first 2 weeks is considered the_____ ______ where the germ layers will form. The next few weeks (3-8 weeks of development) is considered the _____ PERIOD, and the subsequent months are considered the ____ PERIOD.

Answer 24

The first 2 weeks is considered the GERMINAL PERIOD where the germ layers will form. The next few weeks (3-8 weeks of development) is considered the EMBRYONIC PERIOD, and the subsequent months are considered the FETAL PERIOD.

Question 25

After implantation, the embryoblast begins to differentiate into 3 germ layers:

Answer 25

Ectoderm
Mesoderm
Endoderm

Question 26

Ectoderm

Answer 26

skin, nervous system

Question 27

Mesoderm

Answer 27

Muscle, bone, connective tissue

Question 28

Endoderm

Answer 28

internal organs (most viscera)