Term
| What happens in Sperm migration? |
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Definition
A typical ejaculation contains 300 million sperm
Vaginal acid & Failling to get to the uterus & sperm gets destoryed by leukocytes in the uterus
Less than .001% reaches the general vicinity of the egg. |
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Term
| What happens in Sperm Capacitation? |
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Definition
| Removal of cholesterol from sperm membrane & it becomes more permeable to Ca++ which diffuse into the sperm, which stimulate tail movement & the anterior tip of the sperm contains specialized lysosome called ACROSOME. |
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Term
| Acrosomal Reaction is also known as a |
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Definition
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Term
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Definition
| happens when the sperm contacts an egg, the acrosome undergoes exocytosis. |
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Term
| Where is the Acrosome found? |
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Definition
| The anterior tip of the sperm.. it is a specialized lysosome. |
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Term
| Fertilization happens when? |
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Definition
| Sperm contacts the eggs plasma membrane, the sperm and egg membranes fuse. & nucleus and mid piece of the sperm enters the egg. |
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Term
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Definition
| If two or more sperm enter the egg this will result in polyspermy. |
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Term
| what is the fertilization membrane only function? and describe the 2 different types of blocks.. |
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Definition
| Blocks the possibility of polyspermy. There is a Fast Block which uses ( 50 times the amount of Na [sodium] on outside of cell) Na+ channels on the egg open allowing the sodium to come in, changes the membrane and results in the inhibition of any more sperm binding to the egg. and the slow block Ca++ inflow, Ca++ stimulates cortical reaction vesicles called cortical granules to secrete proteins, which swells with water pushing all the remaining sperms away. |
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Term
| what is the 1st zygote division called |
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Definition
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Term
| Prenatal Development - how many Trimesters |
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Definition
3 trimesters.. the first one is the first 12 weeks
the second is weeks 13-24 and the third is from week 25-birth |
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Term
| What does the first trimester consist of? |
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Definition
| Extends from fertilization through the first month of fetal life. More than half of all embryos die in first trimester. Stress, Drugs, and Nutritional deficiencies |
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Term
| What does the 2nd trimester consist of? |
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Definition
| Most organ development completed. Sonography is used to see anatomical detail in the fetus. Infants born at the end of second trimester have a chance of survival. |
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Term
| What does the 3rd trimester consist of? |
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Definition
| Organs achieve enough cellular differentiation to support life outside the womb. Brain, liver and kidneys require further differentiation after birth. 5.5 lb. or 2.5kg after 35 weeks considered mature. |
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Term
| Biological standpoints ( there are 3) |
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Definition
Pre-embryonic stage
Embryonic Stage
Fetal Stage |
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Term
| Pre-embryonic stage ( 3 parts ) |
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Definition
Cleavage
Implantation
Embryogenesis |
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Term
| Pre-embryonic stage - CLEAVAGE- |
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Definition
| Consists of mitotic divisions that occur in the first 3 days after fertilization. Smaller cells are called blastomeres. At 16 blastomeres the zygote is called Morula. After Morula divided into 100 cells it becomes a hollow sphere called blastocyst with an internal cavity called Blastocoel. The wall of blastocyst has a layer of squamous cells called trophoblast. |
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Term
| What does the trophoblast form? |
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Definition
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Term
| Embryoblast are blastomeres destined to become the _____ itself |
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Definition
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Term
| Implantation takes about how long to complete? |
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Definition
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Term
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Definition
| Blastocyst attaches to the endometrium. Trophoblast becomes syncytiotrophoblast and cytotrophoblast |
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Term
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Definition
| multinucleated mass of cells |
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Term
| Syncytiotrophoblast cells grow into the uterus like roots digesting ________ |
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Definition
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Term
| The __________ reacts to this digrestion by growing over the trophoblast so the conceptus becaomes completely buried in the endometrial tissue |
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Definition
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Term
| what happens in Embryo Genesis |
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Definition
In gastrulation three different cell layers are formed from blastomeres ( embryoblast). Endoderm is the inner lining of the digestive tract.
extraembryonic mesoderm contributes to the formation of placenta. |
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Term
| In the amniotic cavity the _________ separates from the ________ creating the amniotic cavity |
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Definition
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Term
| Embryonic stage consists of |
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Definition
| It begins around day 16 and extends to the end of 8 weeks., the placenta is developed, the embro begins recieving nutrition from the placenta. Germ layers differentiate into organs and organ systems. embryonic folding and organogenesis, embryonic membrances, and prenatal nutrition. |
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Term
| Embryonic folding and organogenesis |
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Definition
| Development of nural tube, pharyngeal pouches, somites are major events of this stage. The formation of nural tube is called Neurulation. Ectoderm cells called neural plate appears along the midline of the embryonic disc. Neural plate cells sinks and becomes a neural groove, the edges of the neural groove meet and close this process creates an enclosed channe, the neural tube. |
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Term
| The formation of the neural tube is called |
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Definition
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Term
| Developmental disorders of the nervous systems |
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Definition
Neural tube defects (NTDs)
Spina bifida
Women can significantly reduce the risk of bearing a child with spina bifida by taking Folic acid (it is a B vitamin)
This works only if taken habitually before the egg is fertilized. Folic acids are ineffective if began after a woman already knows she is pregnant. |
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Term
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Definition
| The face is of normal size but the brain is abnormally small. Profound mental retardation |
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Term
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Definition
| Results in failure of the rostral end of the neural tube to close. Brain tissue degenerates, most of the brain is absent at birth. Generally die within a few hours. |
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Term
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Definition
| Five pairs of pockets that form in the wall of the future throat of the embryo, separated by pharyngeal arches. They give rise to middle ear cavity, tonsil, thymus, parathyroid glands, and part of thyroid. |
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Term
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Definition
Bilaterally paird blocks of mesoderm, represent primitive vertebrate segmentation. Each somite subdivides into three dissues,
Sclerotome, Myotome Dermatome |
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Term
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Definition
| it surrounds the neural tube and gives rise to bone tissue of the vertebral column. |
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Term
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Definition
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Term
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Definition
| is the dermis of the skin and the associated subcutaneous tissue. |
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Term
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Definition
| Amnion - transport sac that develops from Epiblast cells of embryonic disc, completely encloses the embryo and it is penetrated by umbilical cord. Develops symmetrically. Protects the embryo from infection & temperature flucuations, freedom of movement important for mucle development. Important in lung development as the fetus breaths the fluid. Amniotic fluid is formed by filtration of the mothers blood plasma. Fetus urinates into amniotic cavity about once an hour. Amniotic fluid is about 700-1000mL of fluid |
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Term
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Definition
| arises from hypoblast cells and it produces the first blood cells and the stem cells of gametogenesis |
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Term
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Definition
| forms the umbilical ford and becomes part of the urinary bladder. |
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Term
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Definition
| is the outer most membrane, enclosing all the membranes and the embryo. Forms the fetal portion of the placenta |
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Term
| Prenatal Nutrition (fig 4.10) |
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Definition
| Before implantation of the conceptus it absorbs a glycogen(carbohydrate) rich secretion of the uterine glands called uterine milk. as it implants trophoblastic nutrition, Trophoblast digest cells of the endometrium called decidual cells. The decidual cells accumulate a rich store of glycogen, proteins, and lipids which is used by the embryoblast in weeks 1-8 this period is called trophoblastic phase. |
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Term
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Definition
| Placenta is a vascular organ attached to uterine wall and connected to fetus by umbilical cord. Begins week 9 until birth, Placental Phase. |
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Term
| Genetic Disorders - Aneuploidy |
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Definition
| is an abnormal number of chromosomes in the zygote. Chromosomal Nondisjunction - is a failure one of the 23 pairs of chromosomes to separate during meiosis |
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Term
| Genetic Disorders - Zygote will have XXX |
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Definition
Triplo_X syndrome
Triplo X female will be infertile
Intelectual impairments |
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Term
| Genetic Disorders - XXY zygote |
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Definition
Causing Klinefelter syndrome
male will be sterile
average intelligence
undeveloped testes
enlarged breasts |
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Term
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Definition
| Dies due to lack of genes from the X chromosome |
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Term
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Definition
Female with turner syndrome
3% of fetuses survive to birth
webbed neck and widley spaced nipples
at puberty secondary sex characteristic fail to develop. absent ovary / sterile |
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Term
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Definition
Trisomy 13 patau syndrome
Trisomy 18 edward syndrome
Trisomy 21 - most common - down syndrome
*retarded physical development
relatively flat face and enlarged protruding tongue
mental retardation is common
epicanthal folds at corners of the eys
the chance of having child with downs is 1 in 3000 in women under 30. one in 365 at 35 and 1 in 9 at age of 48 |
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