Term
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Definition
| conceptus from fertilization until it is two weeks old |
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Term
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Definition
| conceptus during the third through the eighth week |
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Term
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Definition
| conceptus from the ninth week through birth |
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Term
| For how much time is the oocyte viable for? |
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Definition
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Term
| For how long is sperm viable for? |
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Definition
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Term
| What is an ovulated oocyte encapsulated by? |
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Definition
| corona radiata and zona pellucida |
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Term
| After sperm binds to the zona pellcuida what happens? |
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Definition
| it undergoes the acrosmal reaction |
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Term
| What is the acrosomal reaction? |
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Definition
| enzymes are rleleased near the oocyte, hundres of acrosomes release their enzymes to digest the zona pellcuida |
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Term
| What is the role of the beta protein after sperm makes contact with the oocyte's membrane? |
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Definition
| finds and binds to receptors on the oocyte membrane |
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Term
| What is the role of the alpha protein after sperm makes contact with the oocyte's membrane? |
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Definition
| causes sperm to insert into the membrane |
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Term
| What are the two mechanisms that ensure monospermy? |
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Definition
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Term
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Definition
| membrane depolarization prevents sperm from fusing with the oocyte membrane |
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Term
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Definition
| zonal inhibiting proteins destroy sperm receptors, cause sperm already bound to receptors to detach |
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Term
| What happens to the secondary oocyte after entry of the sperm? |
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Definition
| meiosis II is completed, casts out second polar body |
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Term
| What happens after the second polar body is cast out? |
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Definition
| ovum nucelus swells, and teh two nuclei approach each other |
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Term
| What are teh two nuclei called when fully swollen? |
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Definition
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Term
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Definition
| when the pronuclei come together |
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Term
| Preembryonic Development: First cleavage |
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Definition
| two daughter cells produced called blastomeres |
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Term
| Preembryonic Development: Morula |
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Definition
| 16 or more cell stage (72 hours old) |
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Term
| Preembryonic Development: 4/5th day |
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Definition
| preembryo consists of 100 or so cells, (blastocyst) |
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Term
| Preembryonic Development: Blastocyst |
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Definition
| fluid filled hollow sphere |
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Term
| What is the blastocyst composed of? |
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Definition
| single layer of trophoblasts, an inner cell mass |
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Term
| What do trophoblasts take part in? |
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Definition
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Term
| What does the inner cell mass become? |
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Definition
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Term
| What are the steps to embryo? |
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Definition
| implantation, placentation, gastrulation, organogenesis, neuralization |
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Term
| When does implantation begin? |
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Definition
| 6-7 days after ovulation when the trophoblasts adhere to a properly prepared endometrium |
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Term
| What happens after the blastocyst is implanted? |
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Definition
| covered over by endometrial cells |
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Term
| When is implantation completed? |
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Definition
| by the 14th day of ovulation |
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Term
| How is the viability of the corpus luteum maintained by? |
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Definition
| hCG made by developing embryo trophoblasts |
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Term
| What is another role of hCG? |
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Definition
| prompts the corpus luteum to continue to secrete progesterone and estrogen |
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Term
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Definition
| developed from trophoblasts after implantation, continues this hormonal stimulus |
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Term
| What is the placenta doing between the second and third month? |
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Definition
| assumes the role of progesterone and estrogen production, providing nutrients and removing wastes |
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Term
| What tissues does placenta formation develop from? |
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Definition
| embryonic trophoblastic tissues, maternal endometrial tissues |
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Term
| What other hormones does the placenta secrete? |
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Definition
| human placental lactogen, human chorionic thyrotropin, relaxin |
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Term
| How long does it take the placenta to be fully formed and functional? |
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Definition
| by the end of the 3rd month |
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Term
| What is the role of human placental lactogen? |
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Definition
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Term
| What is the role of human chorionic thyrotropin? |
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Definition
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Term
| What is the role of relaxin? |
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Definition
| cause the pelvic ligature to relax |
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Term
| What are teh embryonic membranes? |
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Definition
| amnion, yolk sac, allantois, chorion |
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Term
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Definition
| transparent membrane filled with amniotic fluid |
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Term
| What is the role of the amnion? |
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Definition
| provides a buoyant environment that protects the embryo, helps maintain a constant homeostatic pressure |
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Term
| Where does amniotic fluid come from? |
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Definition
| maternal blood and later fetal urine |
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Term
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Definition
| hypoblast cells that form a sac on the ventral surface of the embryo |
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Term
| What is the role of the yolk sac? |
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Definition
| forms part of the digestive tube, produces earliest blood cells and vessels, source of primordial germ cells, source of nutrition in some animals |
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Term
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Definition
| small outpocketing at the caudal end of the yolk sac |
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Term
| What is the role of the allantois? |
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Definition
| structural base for the umbilical cord, becomes part of the urinary bladder |
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Term
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Definition
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Term
| What is the role of the chorion? |
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Definition
| encloses the embryonic body and all other membranes |
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Term
| What is the role of gastrulation? |
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Definition
| set the stage for organogenesis |
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Term
| What happens to the embryonic disc during the 3rd week? |
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Definition
| two-layered embryonic disc becomes a three-layered embryo |
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Term
| What are teh primary germ layers? |
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Definition
| ectoderm, mesoderm, endoderm |
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Term
| What is the primitive streak? |
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Definition
| raised dorsal groove that establishes the longitudinal axis of the embryo |
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Term
| What happens to the first cells that begin to migrate into the primitive streak? |
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Definition
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Term
| What happens to the cells that follow the first cells that begin to migrate into the primitive streak? |
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Definition
| push laterally between the cells forming the mesoderm |
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Term
| What happens to the cells that remain on the embryo's dorsal surface? |
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Definition
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Term
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Definition
| rod of mesodermal cells that serves as axial support |
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Term
| What is the role of teh primary germ layers? |
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Definition
| serve as primitive tissues from which all body organs will derive |
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Term
| What does the ectoderm develop into? |
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Definition
| forms structures of the nervous system and skin epidermis |
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Term
| What does the endoderm develop into? |
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Definition
| forms epithelial linings of the digestive, respiratory, and urogential systems |
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Term
| What does the mesoderm develop into? |
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Definition
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Term
| BY what week are all organ systems recognizable? |
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Definition
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Term
| What is the first event of oragnogenesis? |
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Definition
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Term
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Definition
| gives rise to the brain and spinal cord |
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Term
| What does teh notochord thickening over the ectoderm form? |
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Definition
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Term
| What happens to the neural plate? |
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Definition
| folds inward as a neural groove with prominent neural folds |
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Term
| By the 22nd day, neural folds fuse into a _______ |
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Definition
| neural tube, which pinches off into the body |
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Term
| What does the anterior end of of the neural tube become? |
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Definition
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Term
| What happens to the rest of the neural tube? |
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Definition
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Term
| What happens to the rest of the neural tube? |
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Definition
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Term
| What does the associated neural crest give rise to? |
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Definition
| cranial, spinal, and sympathetic ganglia |
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Term
| WHat does embryonic folding begin with? |
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Definition
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Term
| After lateral fords have formed what appears next? |
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Definition
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Term
| What forms the epithelial lining of the GI tract? |
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Definition
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Term
| After formation the epithelial lining of the GI tract forms what happens? |
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Definition
| Organs of the GI tract become apparent,and oral and anal openings perforate (open) |
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Term
| What else does the endoderm form? |
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Definition
| epithelium linings of the hollow organs of the digestive and respiratory tracts |
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Term
| Specialization of the mesoderm: FIrst evidence |
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Definition
| appearance of the notochord |
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Term
| What are the three mesoderm aggregates that appear lateral to the notochord? |
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Definition
| sclerotome, dermatome, myotome |
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Term
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Definition
| produce the vertebrae and ribs |
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Term
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Definition
| help forms the dermis of the skin on teh dorsal part of the body |
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Term
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Definition
| form the skeletal muscles of the neck, trunk, and limbs |
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Term
| What does the intermediate mesoderm form? |
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Definition
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Term
| What does the somatic mesoderm form? |
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Definition
| dermis of the skin in the ventral region, parietal serosa of the ventral body cavity, bones, ligaments and dermis of the limbs |
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Term
| What does the splanchnic mesoderm form? |
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Definition
| heart and blood vessels, most connective tissues of the body |
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Term
| WHat anatomical changes are present during pregnancy? |
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Definition
| chadwick's sign, breast enlarge/areolae darken, uterues expands |
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Term
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Definition
| vagina develops a purplish hue |
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Term
| Why is lordosis common in pregnant women? |
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Definition
| change of body's center of gravity |
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Term
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Definition
| pelvic ligaments and pubic symphysis |
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Term
| By how much does blood volume increase during pregnancy? |
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Definition
|
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Term
| What causes contractions as birth nears? |
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Definition
| oxytocin and prostaglandins |
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Term
| What are the five signs an infant's status is based on? |
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Definition
| heart rate, respiration, color, muscle tone, reflexes |
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