ANIMAL EMBRYOLOGY

The early stage of development of a multicellular organism, following fertilization and preceding the fetal stage

Embryo

The later stage of prenatal development in mammals, following the embryo stage and continuing until birth

Fetus

Three primary layers of cells formed during gastrulation in the developing embryo: ectoderm, mesoderm, and endoderm. These layers give rise to different tissues and organs in the body

Germ Layers:

What are the 3 germ layers?

Ectoderm, mesoderm and endoderm

The process by which the blastula undergoes morphological changes to form the three germ layers

Gastrulation

An early stage of embryonic development characterized by a hollow sphere of cells, formed after several rounds of cell division following fertilization

Blastula

The process by which the blastocyst attaches to and embeds itself in the lining of the uterus, allowing for pregnancy to be established

Implantation

The process of forming the neural tube from the ectoderm, which gives rise to the CNS

Neurulation

A membranous sac attached to the embryo’s gut, initially providing nutrients for the developing embryo before the placenta forms

Yolk sac

A sac-like structure involved in waste storage and gas exchange in avian and reptilian embryos. In mammals, it contributes the the formation of the umbilical cord and urinary bladd

Allantois

Any substance, organism, or physical agent that can disrupt normal embryonic development and cause birth defects

Teratogen

Undifferentiated cells with the potential to develop into various cell types

Stem cells

The stages of development between fertilization and birth or hatching are collectively called

Embryogenesis

involves the fusion of the mature sex cells, the sperm and egg, which are collectively called the

Gametes

a series of exteremely rapid mitotic divisions.

Cleavage

During cleavage, the enormous volume of zygote is divided into numerous smaller cells called ______________?

Blastoma

Blastoma will then form ______?

blastula or blastocyst (in human development)

This occurs when blastomeres move and change their position.

Gastrulation

What forms when the blastomeres move and change their position?

3 germ layers

After the moving of blastomeres, it is now called?

Gastrula

occurs when the cells interact with one another and rearrange themselves to produce tissues and organs.

Organogenesis

When organogenesis occurs, this stage will now be called?

Neurula

occurs in many species that are not sexually mature yet after they hatch from the egg

Metamorphosis

occurs in many species that are not sexually mature yet after they hatch from the egg. The young organism is called the?

Larva

occurs when a group of precursor cells (germ cells) are set aside to form the gametes. On the other hand, somatic cells give rise to the rest of the body. This process is considered as the first of the many differentiations to occur during animal development.

Gametogenesis

He is the first known embryologist, said that wonder was the source of knowledge.

Aristotle

What is the book of aristotle?

On the Generation of Animals

Aristotle also identified the two major cell division patterns by which embryo are formed:

Holoblasitc and meroblastic

Aristotle also identified the two major cell division patterns by which embryo are formed

Holoblastic and Meroblastic

In cleavage patterns, in general it says:

yolk inhibits cleavage.

encompasses the entirety of the embryo, involving meridional planes that cleave through the animal and vegetal poles of the embryo

Holoblastic cleavage

Two types of complete cleavage

Isolecithal and mesolecithal

What are the types of Isolecithal cleavage (RSBR)

Radial cleavage, Spiral cleavage, Bilateral cleavage, Rotational cleavage (

Cleavage for echinoderms and amphioxus

Radial cleavage

Cleavage for annelids

Spiral cleavage

Cleavage for tunicates

Bilateral cleavage

What are the cleavage for mammals and nematodes?

Rotational cleavage

Cleavage for amphibians

Displaced radial cleavage

A type of holoblastic cleavage with sparse or evenly distributed yolk

Isolecithal

A type of holoblastic cleavage where moderate vegetal yolk distribution

Mesolecithal

Meroblastic is a type of what cleavage

Incomplete

Holoblastic is a type of what cleavage

Complete

What are the types of cleavage for Meroblastic (TC)

Telolecithal and Centrolecithal

This type of cleavage have dense yolk throughout most of cell

Telolecithal

Cleavage for cephalopod mollucs

Bilateral

Cleavage for fish, reptiles and birds

Discoidal

A type of cleavage where a yolk is in the center of egg

Centrolecithal

cleavage for most of insects

Superficial

Within the blastocyst, two tissue layers differentiate:

trophoblast and the inner cell mass (ICM)

The outer trophoblast will develop into structures that _______________, help the growing embryo implant in the uterine lining, and contribute to the formation of the placent

provide nutrients

The outer trophoblast will develop into structures that provide nutrients, help the growing embryo ________ __ ___ ____ ______, and contribute to the formation of the placent

implant in the uterine lining

The outer trophoblast will develop into structures that provide nutrients, help the growing embryo implant in the uterine lining, and contribute to the ______ __ __ ________

formation of the placenta

The cells remaining after blastocoel formation pluripotent, which give rise to the distinctive formation of the fetus

ICM progenitor cells

According to this embryologist “It is not birth, marriage, or death, but gastrulation which is truly the most importan time in your life.“

Lewis Wolbert

a type of cell movement where, infolding of a sheet

invagination

a type of cell movement where, inward movement

involution

a type of cell movement where, migration

ingression

a type of cell movement where, splitting

delamination

a type of cell movement where, movement of epithelial sheets

Epiboly

All organisms originated from

LUCA

those whose underlying similarity arises from their being derived from a common ancestral structure.

Homologous

those whose similarity comes from their performing a similar function rather than their arising from a common ancestor

Analogous

Evolutionary change is based on

Developmental change

is the area of embryology that focuses on the formation of human embryos, fetuses, and prenatal development

Medical embryology

About how many percent of babies are born with some type of birth defect.

3 to 4 %

Abnormalities caused by genetic events (genetic mutations, chromosomal aneuploidies, and translocations) are called

malformations

is a condition in which two or more malformations occur together

Syndrome

is inherited as an autosomal dominant condition.

Holt-Oram syndrome

Holt-Oram syndrome is caused by mutations in the

TBX5 gene

happens when a fetus’s spine doesn’t close completely during embryonic development.

Spina bifida

are developmental abilities caused by exogenous agents (certain chemicals or viruses, radiation, or hyperthermia)

Disruptions

The agents exogenous agents that are responsible for these disruptions are called

teratogens

the study of how environmental agents disrupt normal development is called

Teratology.

is a retinoid which is derived from Vitamin A. It is indicated for severe cystic acne treatment, but it has been classified as teratogenic.

Isotretinoin