Test 1 (1-4) Flashcards
embryology
the study of prenatal development that begins at conception and ends with birth
histology
the study of the microscopic structures and the functions of cells and their tissues.
Primordium
earliest indication of a tissue type or an organ during prenatal development
congenital malformations
birth defects
amniocentesis
amniotic fluid test to detect abnormalities in the chromosomes
meiosis
process of reproductive cell production that ensures correct # of chromosomes
Cleavage
process during prenatal development when mitosis converts a zygote to a blastocyst
fusion
joining of embryonic tissue of two separate surfaces
mesenchyme
made from NCCs & mesoderm
embryonic folding
places tissues in proper positions for further development
intercellular junctions
specialized regions of contact between the plasma membranes of adjacent cells. They are essential to any multi-cellular organism, providing the structural means by which groups of cells can adhere and interact.
desmosome
a cell structure specialized for cell-to-cell adhesion.
hemidesmosome
a cell structure that attaches a cell to a non-cellular surface.
Identify the type of tissue
Simple Squamous Epithelium
(horizontal longer than vertical)
Identify the type of tissue
Simple cuboidal epithelium
(horizontal and vertical equal)
Identify the type of tissue
Simple Columnar Epithelium
(vertical greater than horizontal)
Intramembranous Ossification
Bone development from sheets of mesenchymal connective tissue. (maxillary arch and most of the mandible)
endochondral ossification
Bone development by the replacement of hyaline cartilage (parts of the mandible)
resorption
the dental condition where the body’s cells eat away and dissolve the tooth structure, removing the mineralized tissue.
suppuration
pus, with large numbers of PMN’s (granulocytes) found in the fluid.
synapse
the junction between two neurons or a neuron and effector organs, such as a muscle or gland.
Name the three periods of prenatal development
- ) preimplantation (1st week after conception)
- ) embryonic (2-8 weeks)
- ) fetal (9 weeks to 40 weeks)
In the preimplantation period, list the phases of development
zygote → blastocyst
(1st week after conception)
In the embryonic period, list the phases of development
blastocyst → disc,
disc → embryo,
embryo → folded embryo
(2-8 weeks)
In the fetal period, list the phases of development
folded embryo → embryo,
embryo → fetus
(9 - 40 weeks)
when implantation occurs outside of the uterus, commonly in the fallopian tube.
ectopic pregnancy
In week 1 (preimplantation), name the events that occur within the organism as it develops (in order):
- ) fertilization w/ sperm and ovum
- ) zygote undergoes mitosis (cleavage), to form a morula
- ) morula forms a blastocyst
- ) Blastocyst implants in the endometrium. 2 layers now (trophoblast, embryoblast)
- ) trophoblast layer gives rise to prenatal support tissue, embryoblast layer gives rise to the embryo.
In week 2 (embryonic period), name the events that occur within the organism as it develops (in order):
- ) implanted blastocyst grows via proliferation + morphogenesis.
- ) leads to the formation of bilaminar embryonic disc (epiblast EB layer
[high columnar cells], and hypoblast HB layer [small cuboidal cells]).
- ) suspension of the disc in endometrium between amniotic cavity (EB) and the yolk sac (HB) (embryo sac).
- ) Placenta joins embryo, allowing oxygen, CO2, nutritional, and hormonal substances to exchange.
in week 3 (embryonic period), name the events that occur within the organism as it develops (in order):
- ) development of primitive streak w/in the disc (creating bilateral symmetry)
- ) epiblast layer cells migrate toward hypoblast layer to become mesoderm and embryonic endoderm.
- ) formation of trilaminar embryonic disk (mesoderm, endoderm, ectoderm)
- ) CNS development (brain, spinal cord begin)
A.) ectoderm creates neuroectoderm, within neural plate, that thickens to form neural groove.
B.) Neural groove deepens to become surrounded by neural folds
C.) neural folds meet and fuse to form neural tube.
5.) Formation of somites (38-paired cuboidal segments of mesoderm)
in week 3 (embryonic period), the ectoderm develops into what?
- ) skin epidermis
- ) CNS
- )NCC’s
- ) mammary & cutaneous glands
- ) Histologic feature-Columnar
- ) Origin- Epiblast layer
in week 3 (embryonic period), the endoderm develops into what?
- ) respiratory/digestive system linings
- ) glandular cells
- ) liver/pancreatic cells
- ) Histologic features- Cuboidal
- ) Origin- Migrating cells from epiblast layer
in week 3 (embryonic period), the trilaminar embryonic disc develops two ends called?
- ) Cephalic end (Head end)
- ) Caudal end (Tail end)
in week 3 (embryonic period), the mesoderm develops into what?
- ) connective tissue (such as skin dermis, cartilage, bone, blood, muscle).
- ) excretory and reproductive organs
- ) histologic features- varies
- ) origins- migrating cells from epiblast layer
in week 3 (embryonic period), the Neural Crest Cells develop into what?
- ) components of nervous system pigment cells, connective tissue proper, cartilage, bone, certain dental tissue
- ) Histologic Features- Varies
- ) Origin- Migrating neuroectoderm
What forms at the cephalic end?
oropharyngeal membrane (future location of mouth, the beginning of digestive tract)
What forms at the caudal end?
cloacal membrane (future location of anus, terminal end of digestive tract)
in week 4 (embryonic period), name the events that occur within the organism as it develops (in order):
(Hint/trick to remember-fold, feed, face)
- ) trilaminar embryonic disk undergoes anterior (cephalic) and lateral embryonic folding (endoderm inside ecto+meso)
- ) formation of tube that becomes future digestive tract from cephalic (oropharyngeal membrane) to caudal (cloacal membrane) end. (Foregut [anterior], Midgut [posterior], Hindgut[posterior])
- ) Development of face and neck (primitive eyes, ears, nose, oral cavity, and jaw areas)
These are environmental factors that can induce changes in the developing embryo:
teratogens
This is an array of the metaphase stage chromosomes of a single cell used to determine gender and analysis for mutations.
karyotype
Male: XY
Female: XX
Down syndrome is associated with what chromosome?
21
After a zygote cleaves through mitosis it is now called a ________
morula
After a morula cleaves through additional mitotic divisions it is now called a __________
blastocyst
The difference between a morula and a blastocyst is that a blastocyst has a ________ and a morula does not
cavity
The outer cell mass of a blastocyst is called a ____________
trophoblast
The inner cell mass of a blastocyst is called a __________
embryoblast
These cells migrate from the crests of the neural folds and disperse within the mesenchyme
neural crest cells (NCC’s)