Animal Development Flashcards
Na
Development begins at
Fertilization
The head of the sperm has a membrane-bound _______ filled with _______
Arcosome / enzymes
When released enzymes in the sperm digest a pathway through the _____ _______
Zona pellucida
Where does the sperm bind in the oocyte
Zona pellucida
When is fertilization complete
When the sperm and eggs pronucleus contribute chromesomes to the zygote
3 parts of sperm
Tail, middle piece, head
What is the sperms nucleus covered by?
Acrosome
The egg cell ( secondary oocyte) is surrounded by a few layers of adhering follicular cells, called the …..
Corona radiata
Function of the corona radiata
Nourish the oocyte when it was in a follicle of the ovary
The oycte has an extra cellular matrix termed _____ ______ just outside the plasma membrane, beneath the corona radiata
Zona pellucida
What happens when the first sperm binds with the oocyte
Upon contact the lo oocyte plasma membrane depolarizes instantly repealing sperm: “Fast Block”
What happens after “fast block”
Depolarization of the plasma membrane
What is “Slow Block”
When vesicles called Cortical Granules release enzymes to prevent sperm from entering the Zona Pellucida
What brings sperm into the oocyte
Microvilli ?
Once in the oocyte the sperm releases chromatin which forms chromesomes enclosed within the sperms ….
Pronucleus
After the egg and sperm form a pronucleus what happens?
The are surrounded by a Single Nuclear Envelope
Process of regulated growth and Differentiation of cells and tissues
Development
3 stages of Embryonic Development
- Cellular
- Tissues
- Organ
Stage of multicellular organism that develops from a zygote before it becomes fre-living;
In seed plants, the ____ is part of the seed
Embryo
Cellular stages of Embryonic Development (2)
Cleavage
Blastula
Spherical mass of cells resulting from cleavage during animal development prior to the blastula stage
Morula
The morula continues to divide, forming a _____
Blastula
The blastula is a hollow ball of cells having a fluid-filled cavity called a
Blastocoel
The _____ forms when the cells of the morula extrude Na+ into extracellular spaces, water follows due to _______, collecting in the center
Blastocoel / osmosis
Early Embryonic Development has two main events
Cleavage & Gastrulation
Once the blastocoel is formed the next phase of Embryonic Development called _________ begins
Gastrulation
This is characterized by an invagination to form cell layers of a caplike structure
Gastrulation
In early Gastrulation certain cells push or invaginate into the …..
Blastocoel
Early gastrula has 2 layers of cells the outer ____ & the inner _____
Ectoderm / Endoderm
The ectoderm gives rise to what
Nervous system & outer layer of integument
The endoderm gives rise to….
Lining of the digestive tract and associated structures
The pore or hole created by invagination is called…
The blastopore
Late 3rd layer of cells is formed in late Gastrulation is the …..
Mesoderm
What does the Mesoderm give rise to….
Which layer is it?
Muscle, several internal organs, connective tissue
Middle
What are the 3 Embryonic Germ Layers
Ecto, Meso, Endoderm
What is the result from Gastrulation:
3 germ layers
Nervous system, epidermis / derivatives, and epithelial lining of oral cavity and rectum
Come from this germ layer
Ectoderm
Musculoskeletal system, dermis, cardiovascular, urinary lymphatic, reproductive systems
Most epithelial linings
Outer layer of respiration and digestion system
Arise from this germ layer
Mesoderm
Epithelial lining of digestive tract and respiration tract
Associated glands of these systems
Epithelial lining of urinary Bladder, thyroid and parathyroid glands
Arise from this germ layer
Endoderm
Cartilage like supportive dorsal rod in all chordates at some point in their life cycle.
What is it replaced with in humans
Notochord
Vertebrae
Formed by the closure of the neural groove during development. In vertebrates this structure develops into the spinal cord and brain
Neural Tube
This region of the dorsal surface of the chordate embryo marks the future location of the neural tube
Neural plate
The _____ is a band of cells that develops where the neural tube pinches off from the ectoderm
Neural Crest
A primitive gut tube is formed by the….
Endoderm
Development requires 3 interconnected processes:
Growth, Cellular Differentiation, Morphogenesis
This produces the bodys shape and form
Morphogenesis
Define Totipotent:
A cell that has a complete genetic potential of the organism
Name 2 mechanics that lead to differential gene expression
Cytoplasmic Segregation
Induction
One of the substances present in the egg that influences development
Matenal Determinate
______ is the distribution of of maternal determints as mitosis occurs
Segregation
_____ is the ability of 1 Embryonic Tissue to influence the Development of another
Induction
Cells closest to the ____ _____ become endoderm, those further way become ______ , and those furthest away become _____
Primary organizer, Mesoderm, Ectoderm
_____ ______ is the process that enables Morphogenesis
Pattern formation
In Pattern Formation, cells of the embryo _____ & ______
Divide and differentiate
The task of ____ ______ is to divide the anterior posterior axis into broad regions
Gap genes
The products of ____ _____ ______ may stimulate or supress the expression of other genes, particularly the segment-polarity gene
Pair Rule Gene
This type of gene ensures each segment has boundaries
Segment Polarity Gene
Homeotic genes are often referred to as ____ _____
Selector Genes
What is the responsibility of Homeotic Gene
They dictate which body parts arise from which segment
Give an example of homeotic transformation
Wings instead of antenna
_____ ______ control pattern formation
Homeotic Genes
Pattern Formation is an aspect of ________
Morphogenesis
Conserved DNA-Binding region of transcription factors encoded by the homeobox of Homeotic Genes
Homeodomain
Homeotic Genes code for _____ ______
Transcription Factors
Proteins that bind to regulatory regions of DNA & Determine if specific genes are active or not
Transcription Factors
The ________ is the DNA binding portion of the transcription factor
Homeodomain
Mutations in a different HOX gene cause _________, a rare condition in which there are extra fingers and toes
Synpolydactyly
Define Morphogen
Protiens that diffuse away from the areas of high concentration in the embryo; forming gradients that influence patterns of tissues
Cytoplasmic segregation is responsible for
Polarity: assigning a head assigning a head and a tail / a top or a bottom to the cell
Define Gastrula
an embryo at the stage following the blastula, when it is a hollow cup-shaped structure having three layers of cells.
Define pattern formation
the developmental process by which cells acquire different identities, depending on their relative spatial positions within the embryo. Pattern formation ensures that tissues and organs develop in the correct place and orientation within the body.
What is pattern formation?
the developmental process by which cells acquire different identities, depending on their relative spatial positions within the embryo.
What is fertilization and Implantation in the endometrium called
Conception
What is Parturition
Giving birth
How long is Embryonic Development
How long is fetal Development
1 - 2 months
3 - 9 months
When are the major organs formed
Embryonic Development
What is the chorion
Contributes to the placenta in mammals
What is the Amnion
Forms a fluid filled sac of amniotic fluid
What is the Allantois
Contributes to the umbilical blood vessels in mammals, collects nitrogen waste
What is the yolk sac
First site for blood cell formation
What is the placenta
An organ that provided nourishment & oxygen / takes it away
The blood vessels of the _______ Accumlate the small amount of urine produced
Allantois
How long after fertilization is Clevage?
Morula?
Blastual
30 hrs
3 days
5th day
Where does the embryo implant itself
Uterine lining
The single layer of outer cells to a blastcyst is called the ….
Trophoblast
Early function of the Trophoblast is ….
Nourishment
The embedding of an embryo at the blastocyst stage into the endometrium is called
Implantation
About when does Gastrulation occur?
2nd week
Inner cell mass flattens out to become…
Name it’s first 2 layers
Embryonic Disk
Ecto and Endo Derm
The embryonic Disk elongate to become ______ ______ & the third layer called the ______ forms.
Primitive Steak / Mesoderm
Umbilical Cord Transports waste material to the
Placenta
List events at the 3 stages of birth
- Cervix dilates and Amnion burst out
- Born & umbilical cord cut
- Placenta Delivered
What are telomeres and what do they do?
how do they affect aging.
Telomeres are the DNA sequences at the end of chromosomes.
They protect the chromosomes from deterioration
Most cells can only divide a limited number of times.
But the enzyme telomerase allows the telomeres to regrow, allowing them to divide more
How do stem cells and cancer divide forever?
The enzyme telomerase lengthens the telomere allow for more division
2 types of cellular damage
Accumulation of harmful DNA
Cross linking of proteins such as collagen
How does aging affect the integumentry system?
Skin is thinner and less elastic due to collagen fibers cross linking with eachother
How does aging affect the cardiovascular system
Atherosclerosis
Weaking of heart muscle
Maximum heart rate decreases
How does aging affect the immune system
Less T cells due to the Thymus involuting
B cells response also declines due to the lack of T cells
How does aging affect the Reproductive system
Males and females
Males: Lower Testosterone
Females: Menopause
During menopause the Ovaries become unresponsive to _______ _______ produced by the anterior pituitary
Gonadotropin hormones
What happens to the Ovaries when they are unresponsive to Gonadotropin hormones
They no longer secret estrogen or progesterone
How does involution of the thymus lead to decreased response to vaccines in older people
Less T cells are produced, the T cells is needed to stimulate the B cells ( which produces Antibodies)
Define Menopause and explain why it happens
Menopause is when the Ovarian and Uterine cycle stop. This is due to the Ovaries becoming unresponsive to Gonadotropic hormones from the anterior pituitary.
Thus estrogen and progesterone secretion stops
2 hypothesis of aging and examples of each
Preprogrammed Theory suggest aging is partly geneticly programmed; Single gene mutations
Damage accumulation theories suggest aging is due to cellular Damage of Free radicals, Cross Linking, and DNA mutations
During the Morula and Blastula stages the organism is referred to as a(n)
Embryo
Invagination of cells into the blastocoel is called
Gastrulation
What controls pattern formation
Homeotic Genes
Homeotic Genes all contain ….
A homeobox
What is a homeobox
A shared nucleotide sequence that codes for a sequence of 60 amino acids called a homeodomain
A shared nucleotide sequence of 60 amino acids is called a
Homeodomain
The portion of the protein that binds to DNA
Homeodomain
The morula becomes the ______ before implanting in the _____ of the uterus
Blastocyst / endometrium
The morula becomes the ______ before implanting in the _____ of the uterus
Blastocyst / endometrium
The ______ of the blastocyst is the first sign of the chorion
Trophoblast
After Implantation the trophoblast secrets ______ which maintains the corpus luteum and is also the basis of pregnancy testing
HCG (Human Chorionic Gonadotropin)
How does the fetus recieve nutrients from the mother
Name the feature of the organ that aids in this
Exchanges between the blood
Facilitated by Chorionic Villi
What 2 features form the Umbilical Cord
Yolk Sac and Allantois
Organ development begins with the _____ and the formation of the ______
Neural tube/ Heart
Insertion a needle into amniotic fuild to check for birth defects
Amniocentesis
Chorioni villi sample allows…
The embryo to be tested for anomalies
