Exam 2 Flashcards
Define ontogenesis:
the growth of an organism from its early stages to maturity
define odontogenesis:
the process of tooth formation
define morphogenesis:
the process of size and shape formation
define growth:
the proliferation of new cells
define development:
the changing of cells into specific tissue types
define tissue:
a group of cells with specialized functions
define organ:
a structure comprised of 2 or more tissues
define germ layer:
a group of embryonic cells that interact with each other to contribute to the formation of different organs and tissues
What are the components of the germ layer?
- endoderm
- mesoderm
- ectoderm
- neural crest cells
- ectomesenchyme cells
define endoderm:
the inner germ layer that differentiates into the lining of the tracts and organs
define mesoderm:
the middle germ layer that differentiates into connective tissues
define ectoderm:
the outer germ layer that differentiates into epithelial tissue and nervous tissue
when the ectoderm differentiates into epithelial tissue what part of the tooth does it eventually produce?
the ameloblasts
define neural crest cells:
cells from the ectoderm that contributes to the smooth muscle, peripheral nervous system
what do neural crest cells occasionally induce into?
ectomesenchyme cells
What do cells from the ectoderm eventually become in reference to the germ layer?
neural crest cells
define ectomesenchyme cells:
cells that produce the dentin, pulp, cementum, periodontal ligament, gingiva, and the alveolar bone
define induction:
a group of cells will direct the development of a second group of cells
define diferentiation:
when the second group of cells from induction changes from one type to another
True or False: In the process of odontogenesis tissues will always affect each other unidirectionally
False
In the process of odontogenesis how is induction carried out?
through molecular signaling (i.e. enamel knot)
true or false: in the process of odontogenesis induction includes the process of differentiation
true
define epithelium:
tissues on the outer layer from the ectoderm germ cells
define mesenchyme:
connective tissue from the mesoderm germ cells
True or false: The epithelium and mesenchyme have reciprocal molecular signaling
true
what are some examples of what the signaling between the epithelium and mesenchyme form?
teeth, hair, feathers, breasts
When does the fertilization of an egg occur and where does it usually happen?
it occurs when the sperm penetrates the outer ovum layer in the fallopian tube
How is a zygote produced?
the combining of the nuclei of the male and female germ cells
define morula:
a ball of cells
what occurs at about 3-4 days after fertilization?
the zygote undergoes cell division producing a morula
define blastocyst:
a group of cells that becomes an embryo
what occurs at about 5-7 days after fertilization?
cell division continues and forms a blastocyst
what occurs at about 7-10 days after fertilization?
implantation occurs as the blastocyst penetrates the inner layer
When does the blastocyst phase occur?
at about 10-13 days after fertilization
What occurs during the blastocyst phase?
inner mass cells begin to flatten and differentiate into the formation of the endoderm and ectoderm, while the amniotic cavity forms
when does the gastrula phase begin?
at about 16 days after fertilization
what occurs during the gastrula phase?
the cells migrate inward while further differentiation occurs causing the formation of the mesoderm between the endoderm and ectoderm
when does the neurulation phase occur?
at about 30 days after fertilization
what occurs during the neurulation phase?
three germ layers, mesoderm, ectoderm, and neural crest cells, develop into organs and associated tissues
during the neurulation phase how is the mesoderm germ layer affected?
the cells in the mesoderm form a notochord and become a verbal column
during the neurulation phase how is the ectoderm germ layer affected?
the ectoderm layer folds inward (pitches off -> neural tube -> spinal cord)
during the neurulation phase how are the neural crest cells affected?
the cells differentiate after neural tube creatin a unique embryonic tissue in vertebrates
true or false: the differentiation of neural crest cells during the neurulation phase is hugely important for the peripheral nervous system and teeth
true
What two tissues does odontogenesis focus on?
Epithelium
Ectomesenchyme cells
