Vertabrate Embryology

Front 1

Fertilization

Back 1

-Fertilization can occur within 12-24 hours of ovulation

-Fertilization occurs in the lateral, widest portion of the oviduct

-Fertilization of more than one egg results in fraternal twins

Front 2

Cleavage

Back 2

A series of rapid mitotic divisions that lead to an increase in cell number without an increase in cell protoplasm

Front 3

1. Indeterminate Cleavage

2. Determinate Cleavage

Back 3

1. A cleavage that result in cells taht maintain the ability to develop into a complete organism (identical twins)

2. A cleavage that results in cells whose future differeniation pathways are determined at an early developmental state.

Front 4

Cleavage Timing

Back 4

First Cleavage: 32 hours
Second Cleavage: 60 hours
Third Cleavage: 72 hours at which time the 8-celled embryo reaches the uterus

Front 5

1. Morula

2. Blastulation and Blastoceoel

4. Blastula

Back 5

1. A solid ball of embryonic cells

2. Blastulation begins when the morula develops a fluid filled cavity called teh blastocoel

3. A hollow sphere of cells formed by the fourth day

Front 6

Gastrula

Back 6

Once implanted in the utuerus, cell migrations transform the single cell layer of the blastula into the three-layerd gastrula.

Front 7

Gastrula Germ Layer: Ectoderm

Back 7

Responsible for the differntial development of the epidermis, hair, nails, epithelium of the nose, mouth, and anal cavity, the lens of the eye, the retina, and nervous system.

Front 8

Gastrula Germ Layer: Endoderm

Back 8

Responsible for the differntial development of the epithelial linigs of the digestive and respitory tracts, and parts of the liver, pancreas, thyroid, and bladder lining.

Front 9

Gastrula Germ Layer: Mesoderm

Back 9

Responsible for teh differential development of teh musculoskeletal system, circulatory system, excretory system, gonads, connective tissue throughout the body, and portions of the digestive and respitory organs.