Intro To Embryology And Key Terms

Question 1

What is embryology and development

Answer 1

• study of animal development from fertilization to birth

- continuous process of gene directed sequences through an organisms life time

Question 2

Which is faster !? Prenatal or post natal

Answer 2

Pre natal

Question 3

What is teratology

Answer 3

-Division of embryology that deals with abnormal development and birth defects

Question 4

Objectives of development

Answer 4

1 ensure continuity of life from one generation to the next

2 generates cellular diversity and order within an org

Question 5

Significance of embryology

Answer 5

1 develops knowledge of beginnings of life and changes during prenatal development

2 extends genetics -how genes direct development

3 helps understand cause of human variation.

4 explains how normal and abnormal relations develop

5 Bridges gap between prenatal development and other fields of medicine

Question 6

Approaches to embryology

Answer 6

1 anatomical
2 experimental
3 genetic

Question 7

What is epigenesis and preformation

Answer 7

-new orgs can be formed from the scratch : relatively discorded cytoplasms of eggs

-organs already present in
Miniature form
In egg or sperm

Question 8

List the stages of development and what occurs at each stage

Answer 8

1 gametogenesis : oogenesis and speematogenesis

2 fertilization : fusion of male and female sex gametes to form a zygote

3 cleavage : series of rapid divisions of zygote to form blastomeres

4 gastrulation : transformation of blastocyst into gastrula

5 differentiation: cells acquire morphological and physiological changes diff from other cells and and for a specific function

6 organogenesis : formation of organs shortly after gastrulation

7 growth
8 metamorphosis: drastic change in body structure
9 regeneration
10 aging : gradual loss of structure and function

Question 9

What is a neurula and embryo

Answer 9

• embryo in 3 and 4th week when neural tube is developing

- developing human during early stages of development

Question 10

Describe the embryonic period

Answer 10

• beginning of all major structures present
• from fertilization to 8th week
• very sensitive to teratogens
• developmental changes are drastic

Question 11

List and describe the times and activities the stages of prenatal development

What is a fetus

Answer 11

• stage 1 : embryonic period from fertilization to week 8.
• stage 2 : fetal period from day 57 to birth. Diff and growth of tissue and organs

Fetus is an unborn offspring

Question 12

What is conceptus

Answer 12

• embryo and embryonic part of placenta and it’s membranes
• amnion
• chorion
• yolk sac / umbilical vesicle

Question 13

What is abortion and types

Answer 13

-premature stoppage of development and exclusion of conceptus from the uterus or of embryo or fetus before it is viable

• miscarriage
• threatened
• spontaneous
• induced
• habitual

Question 14

What is trimester and what is the most critical stage

Answer 14

• 3 calender months during pregnancy

- 1st trimester most critical

Question 15

What is postnatal period and infancy

Answer 15

• after being

- 1st year of birth

Question 16

What is a newborn or neonate

Answer 16

-1st month of a newborn

Question 17

What are oocytes and sperm and where are they made

Answer 17

• female and male sex cells

- ovaries and testes

Question 18

What is spermatogenesis and describe its steps

Answer 18

-sperm formation in the testes
1 spermatogonium
2 primary spermatocyte - larger 46XY
3 secondary spermatocyte- from 1st meiotic division of primary ( 23X and 23Y )
4 spermatids - 4 of them from 2nd meiotic division of 2nd spermatocytes

Question 19

What is oogenesis and where done and its steps

Answer 19

-oocyte formation and done in the ovaries
1 primary oocyte with 1 follicular layer thick ( 46XX )
2 primary oocyte now has multi layer follicular layer ( 46 XX )
3 primary oocyte now has larger follicular layer and a developing zona pellucida
4 secondary oocyte from 1st meiotic division from 1• oocyte ( 23X ) is unfertilized and has 1 polar body and large follicular layer with Antrum space

5 2• oocyte undergoes 2nd meiotic Division
Has corona radiata layer

Question 20

What is Marula

Answer 20

• ball of cells from blastomeres

- 12-32 cells

Question 21

What is blastocyst and function

Answer 21

• morula develops a fluid filled cavity ( archenteron ) and becomes blastocyst
• implants into receptive uterus
• has degenerated or degenerating zona pellucida

Question 22

What happens during gastrulation and describe ingression

Answer 22

• cells migrate inwardly and form tri laminar germ layer

- ingression occurs ( morphogenetic mechanism ) inward migration of epiblast cells through primitive streak

Question 23

How is notochord formed

Answer 23

-some mesenchymal cells migrate through streak cranially and form notochordal process later into notochord