Embryology Flashcards
(98 cards)
1
Q
Series of progressive changes in an individual from its beginning to maturity
A
Development
2
Q
When does development begin?
A
It begins when a fertilized egg divides mitotically
3
Q
Specialization occurs as a
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hierarchy of developmental “decisions”
4
Q
Key events in animal development
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Gamete formation > Fertilization > Cleavage/Blastulation > Gastrulation > Organogenesis > Growth
5
Q
Key events in animal development: Sperm and egg form, mature
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Gamete formation
6
Q
Key events in animal development: Egg and Sperm fuse
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Fertilization
7
Q
Key events in animal development: Zygote subsides, determinants partitioned in blastomeres
A
Cleavage/Blastulation
8
Q
Key events in animal development: Germ Layer Forms
A
Gastrulation
9
Q
Key events in animal development: Body organs form, cells interact, differentiate
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Organogenesis
10
Q
Key events in animal development: Organs increase in size, adult body form attained
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Growth
11
Q
Fertilization and Activation
- A century of research has been conducted on_______
- Especially _________
A
marine invertebrates, sea urchins
12
Q
Contact and Recognition Between Egg and Sperm in Marine organisms: how much sperm do marine organisms release in the ocean to fertilize eggs
A
enormous numbers of sperm
13
Q
Contact and Recognition Between Egg and Sperm in Marine organisms: Many eggs release what in order to attract sperm of the same species
A
a chemical molecule, this is also known as chemotaxis
14
Q
After sperm and egg membranes fuse: the Sperm loses what
A
its flagellum
15
Q
After sperm and egg membranes fuse: ___________ migrates inward to contact the female nucleus
A
Enlarged sperm nucleus
16
Q
After sperm and egg membranes fuse: Fusion of male and female nuclei forms a ________
A
diploid zygote nucleus
17
Q
Sets in motion important changes in the egg cytoplasm
- Fertilized egg called a zygote
A
Fertilization
18
Q
Most animals proceed through these stages during development:
A
Zygote > Early cleavage stages > Gastrulation > Body plan (Segmentation) > Morphogenesis
19
Q
Most animals proceed through these stages during development: Fertilized egg
A
Zygote
20
Q
Most animals proceed through these stages during development: blastula, establish polarity and body axes
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Early cleavage stages
21
Q
Most animals proceed through these stages during development: Establish germ layers
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Gastrulation
22
Q
Order of germ layer formation
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First: Ectoderm.
Second: Endoderm.
Third: Mesoderm.
23
Q
Most animals proceed through these stages during development: In vertebrates, this involves neurulation
A
Body plan (Segmentation)
24
Q
Most animals proceed through these stages during development: Organogenesis
A
Morphogenesis
25
Embryo divides repeatedly
Cleavage
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is a solid mass of cells (blastomeres)
Morula
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The embryo with 8 to 16 blastomeres is called a _______
Morula
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Cleavage and Early Development: No cell growth occurs, only subdivision until cells reach regular somatic cell size (True or False)
True
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At the start of cleavage, Zygote has been divided into many hundreds or thousands of cells (True or False)
False (At the END not Start of cleavage)
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a two-layered ball of cells formed by a dynamic rearrangement of blastomeres
Blastula
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32-cell stage of division
Blastula
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Hollow, fluid filled cavity
blastocoel
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Cleavage: Amount of Yolk, The Three Types
Isolecithal, Mesolecithal, Telolecithal
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Cleavage: Amount of Yolk:
* Very little yolk, evenly distributed
* Use Holoblastic cleavage- full cleavage
Isolecithal
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Cleavage: Amount of Yolk:
* Moderate yolk
* Use Holoblastic - full cleavage
Mesolecithal
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Cleavage: Amount of Yolk:
* Have an abundance of yolk
* Use Meroblastic cleavage - partial cleavage
Telolecithal
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Patterns of Embryonic Cleavage: The Two Types
Holoblastic & Meroblastic
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Patterns of Embryonic Cleavage:
* Cleavage extends entire length of egg
* Egg does not contain a lot of yolk, so cleavage occurs throughout egg
*Example: mammals, sea stars, worms
Holoblastic
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Patterns of Embryonic Cleavage:
* Cells divide sitting on top of yolk
* Too much yolk and yolk can’t divide
* Examples: birds, reptiles, fish
Meroblastic
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Blastulation: Cleavage creates a cluster of cells called the_____
blastula
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Blastulation: Blastula stage typically consists of a ________ cells
few hundred to
several thousand
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Blastulation: In most animals
Cells are arranged around a fluid-filled cavity called the ______
blastocoel
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Blastulation: During blastula stage, the first germ layer formed is _______
Ectoderm
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Gastrulation: Results in the formation of Two Germ Layers
Endoderm and Mesoderm
Gastrulation
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Gastrulation: During grastula stage, the second germ layer formed is _______
Endoderm
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Gastrulation: Involves an _______of one side of blastula
Forms a new internal cavity called_________
invagination - gastrocoel
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Gastrulation: Opening into the cavity is called ______
Blastopore
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Gastrulation: Gastrula has an outer layer of ________ and an inner
layer of ________
ectoderm - endoderm
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Gastrulation: Animals with two germ layers are called
Diploblastic (Endoderm and Ectoderm)
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Gastrulation: Most animals who add a 3rd germ layer are called
Triploblastic
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Gastrulation: Mesoderm
* ______ germ layer
*Forms ______ the endoderm and the ectoderm
*Mesoderm arises from _______
3rd, between, endoderm
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Developmental Characteristics: Germ Layer Outcomes during
Morphogenesis: Epithelium and nervous system
Ectoderm
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Developmental Characteristics: Germ Layer Outcomes during
Morphogenesis: Epithelial lining of the digestive and respiratory tract, liver, pancreas
Endoderm
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Developmental Characteristics: Germ Layer Outcomes during
Morphogenesis: Muscular system, reproductive system, bone, kidneys, blood, notochord
Mesoderm
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Developmental Characteristics: Neurulation: formation of a ______ from the ______ of the embryo
neural tube - ectoderm
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Developmental Characteristics: Neurulation: happens in ______ & _______ embryos
chordates and vertebrate
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Developmental Characteristics: Neurulation: the embryo at this stage is termed the _____
neurula
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A developmental congenital disorder caused by the incomplete closing of the neural tube during neurulation
Spina bifida
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Formation of the Coelom: Body cavity surrounded by mesoderm
Coelom
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Formation of the Coelom: The method by which the
coelom forms is an _____
inherited character, Important in grouping organisms based on
developmental characters
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Formation of the Coelom: Upon completion of coelom formation
Body has 3 tissue layers and 2 cavities
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Formation of the Coelom: Animals Without a Coelom are called _____
Acoelomates (Ex. flatworms )
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Developmental Characteristics: Two major groups of triploblastic
animals
Protostomes and Deuterostomes
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Developmental Characteristics: Two major groups of triploblastic
animals are identified by four developmental characters
- Cleavage Patterns (radial or spiral)
- Fate of Blastopore (mouth or anus)
- Coelom Formation (split mesoderm or outpocketing mesoderm)
- Embryo Type (Regulative or Mosaic)
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Developmental Characteristics: Two major groups of triploblastic
animals are identified by four developmental characters: Cleavage Patterns
radial or spiral
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Developmental Characteristics: Two major groups of triploblastic
animals are identified by four developmental characters: Fate of Blastopore
mouth or anus
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Developmental Characteristics: Two major groups of triploblastic
animals are identified by four developmental characters: Coelom Formation
split mesoderm or outpocketing mesoderm
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Developmental Characteristics: Two major groups of triploblastic
animals are identified by four developmental characters: Embryo Type
Regulative or Mosaic
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Developmental Characteristics: Two major groups of triploblastic
animals are identified by four developmental characters: Protostomes
- Cleavage Patterns: Spiral
- Fate of Blastopore: Mouth first then anus
- Coelom Formation: Split mesoderm (Schizocoelous)
- Embryo Type: Mosaic
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Developmental Characteristics: Two major groups of triploblastic
animals are identified by four developmental characters: Deuterostomes
- Cleavage Patterns: Radial
- Fate of Blastopore: Anus first then mouth (developes a complete gut)
- Coelom Formation: Outpocketing mesoderm (enterocoelous)
- Embryo Type: Regulative
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Coelom Formation - Mesoderm movement:
*Mesoderm sides push outward and expand into a pouch-like coelomic compartment
*Pouch-like compartment pinches off and forms a mesoderm bound space surrounding the gut
*Occurs in Deuterostomes ( Sea stars, fish, frogs, etc.
Enterocoely - Enterocelous Plan
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Coelom Formation - Mesoderm movement:
*Coelom forms from Endodermal cells move to blastopore and develop into mesoderm
*Mesoderm separates or splits to form cavity (coelom)
*Occurs in Protostome (Earthworms, snails)
Schizocoely - Schizocoelous Plan
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Animal Body Plans: Animal Symmetry correspondence of size and shape of parts on opposite sides of a median plane
* Spherical
* Radial
* Bilatera
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Animal Body Plans: Animal Symmetry:
* any plane passing through
* the center divides a body into equivalent, or mirrored, halves
*Examples: unicellular forms and is rare in animals
*Spherical forms are best suited for floating and rolling
Spherical symmetry
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Animal Body Plans: Animal Symmetry:
* Body divided into similar halves by more than 2 planes passing through longitudinal axis
* Usually sessile, freely floating, or weakly swimming animals
* Examples: jellyfish, sea urchin
* No anterior or posterior end
* Can interact with environment in all directions
Radial symmetry
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Animal Body Plans: Animal Symmetry:
* Organism can be divided along a sagittal plane into two mirror portions
* Right and left halves
* Much better fitted for directional (forward) movement
* Example: Most vertebrates
* Associated with cephalization
* Differentiation of a head region with concentration of nervous tissue and sense organs (brain)
Bilateral Symmetry
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Animal Body Plans: Regions of bilaterally symmetrical animal: Head end
Anterior
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Animal Body Plans: Regions of bilaterally symmetrical animal: Tail end
Posterior
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Animal Body Plans: Regions of bilaterally symmetrical animal: Back side
Dorsal
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Animal Body Plans: Regions of bilaterally symmetrical animal: Front or belly side
Ventral
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Animal Body Plans: Regions of bilaterally symmetrical animal: Midline of body
Medial
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Animal Body Plans: Regions of bilaterally symmetrical animal: Sides
Lateral
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Animal Body Plans: Regions of bilaterally symmetrical animal: Parts farther from the middle of body
Distal
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Animal Body Plans: Regions of bilaterally symmetrical animal: Parts are nearer the middle of body
Proximal
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Animal Body Plans: Regions of bilaterally symmetrical animal: Divides bilateral body into dorsal and ventral halves
Frontal plane (coronal plane)
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Animal Body Plans: Regions of bilaterally symmetrical animal: Divides body into right and left halves
Sagittal plane
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Animal Body Plans: Regions of bilaterally symmetrical animal: Divides body into anterior and posterior portions
Transverse plane (cross section)
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Body Cavities: One mesoderm lined body cavity, gut cavity - no
coelom.
Acoelomate
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Body Cavities: 2 body cavities, gut and mesoderm lined cavity (false coelom)
Pseudocoelomate
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Body Cavities: have mesoderm lined coelom
Coelomates (Eucoelomate)
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Body Cavities: 3 body cavities, gut and 2 coelom cavities with mesoderm lining
Schizocoelous and Enterocoelous
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Body Cavities: Some animal have NO body cavities or mesoderm give examples
Sponge (no germ layers, no gut)
Cnidarians (gut, but no mesoderm)
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Developmental Origins in Triploblasts Body Plans: Triploblastic animals have 3 germ layers:
Ectoderm, endoderm, mesoderm
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Developmental Origins in Triploblasts Body Plans: Diploblastic animals have 2 germ layers
Ectoderm, endoderm, no mesoderm
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A Complete Gut Design and Segmentation:
Serial repetition of similar body segments along longitudinal axis of body
Metamerism (Segmentation)
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A Complete Gut Design and Segmentation: In Metamerism, each segment is a _____ or _____
metamere or somites
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A Complete Gut Design and Segmentation: Metamerism permits ________________ and ______________
body mobility and complexity of structure and function
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A Complete Gut Design and Segmentation: Examples of organism who do Metamerism or Segmentation
Annelids, Arthropods, Chordates
