Term
| When does prenatal development begin? |
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Definition
| At the start of pregnancy and continues until the birth of the child. |
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Term
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Definition
| Study of prenatal development |
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Term
Prenatal development consists of 3 distinct stages what are they?
What trimesters do these periods make up? |
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Definition
Preimplantaion period 1st
Embryonic period 1st
fetal period 2nd and 3rd |
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Term
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Definition
| Earliest indication of part of an organ during prenatal development. |
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Term
| What is involved with congenital malformations? |
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Definition
| birth defects noticable at birth. Occur in preimplantaion and embryonic stage. Can occur from drugs called tertogens. Can lead to malformations in face neck and oral cavity. |
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Term
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Definition
| Environmental agents or factors that consist of infections, drugs, and radiation. |
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Term
| Describe the preimplantation period? |
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Definition
| period of unattached conceptus that takes place during the first week. Women ovum penetrated by sperm during fertilization. Forms a zygote(fertilized egg) |
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Term
| What is meiosis, and what happens in its final stages? |
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Definition
| process of cell reproduction that ensures correct number of chromosomes for embryo. diploid # of 46. Then reduced to haploid of 23. Full parental chromosomes results in prenatal death. |
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Term
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Definition
| Photographic analysis of a persons chromosomes is arranged in pairs. |
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Term
| Discuss what happens during cleavage and implantation? |
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Definition
| cleavage or mitosis occurs and the cell is converted from zygote to blastocyst. the blastocyst splits and undergoes mitosis to create more cells. Blastocyst travels back to uterus and undergoes implantation. |
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Term
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Definition
| Process during prenatal development when individual cell division or mitosis converts a zygote to a blastocyst |
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Term
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Definition
| Solid ball of cells after initial cleavage |
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Term
| Mitosis that occurs during cell division does what? |
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Definition
| self duplication of chromosomes of the parent cell and the equal distribution to daughter cells. |
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Term
| Where does implantation occur? |
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Definition
| Uterus lining (endometrium). Back wall of uterus toward spine.(optimal place) |
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Term
| What is a blastocyte and what layers are present? |
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Definition
| the former zygote. Consists of trophoblast (peripheral cells), embryoblast layer which is small inner mass of embryonic cells - later gives rise to embryo. |
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Term
| Describe the facial and oral presentaions involved with down syndrome |
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Definition
| flat broad face with wide set eyes, flat bridged nose, epicanthic folds. This is a chromosomal abnormality occuring @ chromosome # 21 |
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Term
| what happens during ectopic pregnancy? |
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Definition
| implantation occured outside the uterus can implant in fallopian tubes due to scarred tubes and cause loss of embryo. |
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Term
| Describe the embryonic period? |
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Definition
| begining of 2nd week to end of eighth week. include induction, proliferation, differentiation, morphogenisis, and maturation. |
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Term
| What happens during induction and proliferation? |
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Definition
action of one group of cells on another that leads to the establishment of the developmental pathway in responding tissues.
Proliferation: controlled levels of cellular growthduring most of the embryological development. |
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Term
| what types of growth can occur in the embryo? |
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Definition
| interstitial: occurs from deep within a tissue or organ. Appositional: tissue enlarges its size by the addition of layers on the outside. |
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Term
| Name and define the different types of differentiation. |
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Definition
| identical cells structurally but functionally take on new specialized paths. beginings of major tissues. Types: Cytodiferentiation, Histodifferentiation, Morphodifferentiation |
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Term
Cytodifferentiation:
Histodifferentiation:
Morphodifferentiation: |
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Definition
1. development of dif cell types
2. Development of different tissues within a structure
3. Differing structure or morphology for each organ system |
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Term
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Definition
| Attainment of adult function and size due to proliferation, differentiation, and morphogenesis |
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Term
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Definition
| the process of development of a specific tissue structure or shape |
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Term
| Define Morphogenesis in relation to the embryo? |
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Definition
| morphogenisis is the migration of embryonic cells and inductive interactions of those cells. |
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Term
| What occurs during the 2nd week of prenatal development? |
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Definition
| the implanted blastocyst grows by increased proliferation of the embryonic cells, as well as morphogenesis and differentiation. |
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Term
| Name the layers of the bilaminar disc and other related tissues |
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Definition
| Superior epiblast layer (columnar cells) and inferior hypoblast layer. (cuboidal cells) |
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Term
| After bilaminar disc creation what happens? |
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Definition
| suspended into the uterus between amniotic cavity (faces epiblast layer) and yolk sac (faces hypoblast layer) Yolk sac = nourishment |
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Term
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Definition
| prenatal organ joins pregnant womans developing embryo. Develops from interactions of the trophoblast layer and endometrial tissues. This permits selective exchange between blood substances |
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Term
| What occurs during the third week of prenatal development? |
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Definition
| The primitive streak forms within the bilaminar disc. |
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Term
| What is bilateral symmetry? |
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Definition
| The primitive streak that causes the disc to divide into right and left half so that each half mirrors the other half of the embryo. |
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Term
| What are the layers of the trilaminar disk? To what do they give rise to? |
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Definition
Former Epiblast layer is Ectoderm.
Former Hypoblast layer is Endoderm.
Mesoderm |
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Term
| What tissues Endoderm, ectoderm, mesoderm give rise to? |
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Definition
1. Endoderm - epithelial linings of respiratory passages and digestive tract, including glandular organ cells
2. Ectoderm - epidermis of skin, nervous system
3. Mesoderm - muscle coats, connective tissue, vessels supplying tissues, organs and other tissues |
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Term
| What are the landmarks of the trilaminar embryonic disk? |
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Definition
Cephalic End - Oropharyngeal membrane - ectoderm and endoderm - Future primitive mouth
Caudal end - cloacal membrane - ectoderm and endoderm - terminal end of digestive tract. |
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Term
| Discuss the early formation of the central nervous system |
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Definition
| specialized cells differentiate from ectoderm. These cells then become neuroectoderm. |
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Term
| What are the neural crest cells, and how are they related to the development of structures in the head and neck region? |
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Definition
| 3rd week neural crest cells develop from neuroectoderm. They disperse into messenchyme and in the future are involved in development of nervous system, connective tissue, cartilage, bone, pulp, dentin, cementem, and periodontal ligament. by influencing ectomesenchyme. |
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Term
| What are somites and how are they related to the development of structures in the embryo? |
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Definition
| 38 paired blocks of mesoderm. Later give rise to most of the skeletal structures of the head neck and trunk as well as muscles and dermis of skin. |
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Term
| Describe the oral complications associated with ectodermal dysplasia? |
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Definition
| Partial or complete anodontia. The absence of some or all teeth. Teeth in both dentitions typically have malformations |
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Term
| What happens during the 4th week of prenatal development? |
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Definition
| Disc undergoes embryonic folding into an embryo establishing for the first time human axis and placing tissue in proper position. |
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Term
| What are the landmarks of the embryo in the fourth week? |
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Definition
foregut: primitive pharynx & primitive yolk sac
Midgut: form rest of digestive tract
Hindgut: form rest of digestive tract. |
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Term
| Discuss the impact that rubella, syphilis, and alcohol can have on the embryo |
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Definition
Rubella: Cataracts, cardiac defects, and deafness
Syphilis: defects in inceisors and molars, blindness, deafness and paralysis
Alcohol: growth deficiency and mental retardation. |
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Term
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Definition
| begining of 9th week - 9th month maturation of existing structures as the embryo enlarges to become fetus |
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Term
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Definition
| originating from epiblasts. embryonic tissue that has the ability to differentiate into diverse types of connective tissues. (fibroblasts, chondroblasts, osteoblasts) creates mesoderm. |
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Term
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Definition
| furrowed rod shaped thickening in the middle of the embryonic disk. |
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Term
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Definition
| folding of embryo that places tissues in there proper positions for future embryonic development. |
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Term
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Definition
| band of cells that extends the length of the embryo from cephalic to caudal end |
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Term
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Definition
| where the neural plate and groove come together to form the neural tube. Future spinal cord. |
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Term
Ectoderm
origin, morph, tissues |
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Definition
| epiblast, columnar, epidermis, ears, nose, nervous system, nueral crest cells, mammary and cutaneous glands |
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Term
Mesoderm
origin,morph,tissues |
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Definition
| migrating cells from epiblast area, varies, dermis, muscle , bone, lymphatics, blood cells and bone marrow, reporductive organs. |
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Term
Endoderm
origin, morph, tissues |
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Definition
| Hypoblast, cuboidal, respiratory and digestive system linings, liver and pancreatic cells |
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Term
Neural crest cells
origin, morph, tissue |
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Definition
| migrating neuroectoderm, varies, portions of nervous system, connective tissue proper, cartilage, bone and certain dental tissues. |
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