Embryogenesis and Development Flashcards
(47 cards)
1
Q
Timeline for Development
A
Fertilization > Cleavage > Blastulation > Gastrulation > Neurulation > Organogenesis
2
Q
Fertilization
A
- Happens in the Fallopian tube
- Sperm binds to Zona pellucida
- Acrosome releases enzymes to penetrate the eggs
- Results in zygote
3
Q
Twins
A
- Dizygotic (Fraternal) twins; Form from 2 different eggs and two different sperm
- Monozygotic (Identical) twins ; When a single zygote splits into two.
If division is incomplete conjoined twins may result. two offsprings are physically attached to each other
4
Q
Cleavage
A
- Rapid mitotic divisions of the zygote
- No growth in overall size - just division
- Results in a morula (Solid ball of cells)
5
Q
Indeterminate cleavage
A
- Results in cells that can still develop into complete organisms
- Where monozygotic twins come from
6
Q
Determinate cleavage
A
- Cell fate is predetermined
- These cells are committed to differentiating into a certain type of cell
7
Q
Blastulation
A
- Morula becomes a blastocyst
- Trophoblast > Surround the blastocoel and later becomes the placenta
- Inner cell mass (ICM) > Embryo
- Blastocoel > fluid-filled cavity
- Implantation occurs in the uterine wall around day 6-7
8
Q
Implantation
A
- The trophoblast cells create an interface between the maternal blood supply and the developing embryo
- These cells give rise chorion (membrane that develops in the placenta)
- They also form chorionic villi that penetrate the endometrium
The umbilical cord - Consist of two arteries and one vein
9
Q
Gastrulation
A
- Form three germ layers
- In humans (Deuterostomes) the blastopore develops the anus
- In Protostomes, it develops into the mouth
10
Q
Primary germ layers
A
- Ectoderm
- Mesoderm
- Endoderm
11
Q
Ectoderm
A
- Attracto-derm
-Hair
- Nails
- Lens of eye
- Teeth
12
Q
Mesoderm
A
- Movement (Muscles, blood, sex organs)
- Bones
- Muscles
- Cardio system
- Connective tissue
- Kidneys
13
Q
Endoderm
A
- Endo - Inside (Digestive and internal organs)
- Liver
- Pancreas
- Thyroid
14
Q
Differentiation
A
Selective transcription - Only genes needed for that particular cell type are transcribed
- Induction - One group of cells influences the fate of nearby cells via chemical signals. This is done by inducers which diffuse from organizing cells to the responsive cells
15
Q
Neurulation
A
- Notochord induces the ectoderm to form neural folds, which surround a neural groove. The folds grow towards one another until they fuse into a neural tube, which gives rise to the CNS.
- Neural plate folds to form the neural tube > CNS
- Neural crest cells > PNS, adrenal medulla
16
Q
Organogenesis
A
- Development of major organs
- Occurs in the first trimester
- Most sensitive to teratogens (Alcohol, drugs, and radiation)
17
Q
Cell determination
A
- Cell is committed to a specific fate (Before visible changes)
- Morphogens - Cause neighboring cells to follow a particular development pathway
18
Q
Cell Differentiation
A
- Cell develops into its final form and function
19
Q
Stem cells
A
- Undifferentiated cells with varying potency; Have the ability to self-renew and differentiate into specialized cell types
- Totipotent, Pluripotent, and multipotent
20
Q
Totipotent
A
- They can become any cell types including embryo + Placenta
- Zygote
21
Q
Pluripotent
A
- They can become all embryonic germ layer cells ( Ectoderm, mesoderm, endoderm), Not placenta
- Inner cell mass of blastocyst
22
Q
Multipotent
A
- They can differentiate into multiple types of cells within a particular group
- Red blood cells, White blood cells, and platelets
23
Q
The stages of Cell specialization
A
Specification, determination, and differentiation
24
Q
Specification
A
- The initial stage of cell specialization
- The cell is reversibly designated as a specific cell type
25
Types of cell-cell communication
-APE-J
- Autocrine
- Paracrine
- Endocrine
-Juxtacrine
26
Autocrine
- Cells signals itself
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Paracrine
- Signals target nearby cells (Short range)
28
Juxtacrine
Requires direct physical contact between adjacent cells
29
Endocrine
Signals travel via bloodstream to distant cells
30
Inducers
- Signaling molecules released by one group of cells that influence the fate of a nearby group of cells
- Inducing cells release molecules (Morphogens)
- Responding cells must be competent
- Important for tissue patterning, organ formation, and germ layer differentiation
- Common inducers - Sonic hedgehog (Shh), Epidermal growth factor (EGF), and Transforming growth factor beta
31
Cell migration
Movement of cells from one location to another during development or repair
- Controlled by chemical cues (Chemotaxis)
- Relies on cytoskeletal rearrangement (actin)
- Errors in migration can lead to birth defects
32
Cell death
Apoptosis - Programmed cell death ; healthy and important in development
Necrosis - Cell death due to injury ; Bad
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Regeneration
Ability to regrow lost or damaged tissue
- Three types > Complete, incomplete, and no regeneration
- Stem cells and growth factors involved
34
Complete regeneration
New tissue is identical to the original
- Liver regeneration
35
Incomplete regeneration
New tissue not identical, some loss function
-Skin, cardiac muscle
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No regeneration
Cells lost permanently
- CNS neurons (Limited regenerations)
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Senescence
Biological aging
38
Placenta
- Where nutrient, gas, and waste exchange occurs at the placenta
- Serves endocrine functions, secreting estrogen, progesterone, and human chorionic gonadotropin (hCG)
39
Placental Barrier
Immune protection against many pathogens and antibodies are transferred from the pregnant individual to child
40
Umbilical Arteries
Carry deoxygenated blood from the fetus to the placenta
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Umbilical Vein
Carry oxygenated blood from placenta back to the fetus
42
Foramen ovale
connects the right atrium to the left atrium, bypassing the lungs
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Ductus arteriosus
Connects the pulmonary artery to the aorta, bypassing the lungs
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Ductus venosus
Connects the umbilical vein to the inferior vena cava, bypassing the liver
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First trimester
Organogenesis occurs
46
Second trimester
Tremendous growth occurs, movement begins, the face becomes distinctly human
47
Third trimester
Rapid growth and brain development continue, transfer of antibodies to the fetus
