page 218-237 Flashcards
root formation
Begins at the cervical loop (where the IEE and OEE join) after enamel is first formed.
As the cervical loop elongates, ——– is
formed, which shapes the root(s) and ultimately surrounds the majority of
the ——-. Its most apical segment, the —— ——–, turns
———-, ensuring that the root tapers as odontogenesis proceeds.
As the cervical loop elongates, Hertwig’s epithelial root sheath (HERS) is
formed, which shapes the root(s) and ultimately surrounds the majority of
the dental papilla. Its most apical segment, the epithelial diaphragm, turns
medially, ensuring that the root tapers as odontogenesis proceeds.
(root formation)
As root formation continues, the tooth erupts, leaving the ——- ——–
always at the same location. This eventually forms the —– foramen.
As root formation continues, the tooth erupts, leaving the epithelial diaphragm
always at the same location. This eventually forms the apical foramen.
As ——- dentin is formed, —– begins to disintegrate, leaving behindpatches of epithelial cells called —– ——- ——-
As radicular dentin is formed, HERS begins to disintegrate, leaving behindpatches of epithelial cells called epithelial rests of Malassez.
The collapse of HERS enables ectomesenchymal cells of the dental follicle to contact dentin and differentiate into the formative cells of the periodontium:
x
y
z
cementoblasts (forming cementum), osteoblasts (forming alveolar bone proper), and fibroblasts (forming the PDL).
tooth eruption
As the tooth erupts into the oral cavity, the —- fuses with the —– ——–,
forming the ——– junction (epithelial attachment).
As the tooth erupts into the oral cavity, the REE fuses with the oral epithelium,
forming the dentogingival junction (epithelial attachment).
—– —- later migrates apically along the tooth to its normal position in which
the most apical cells of the JE are at the —-.
A delay in this apical migration
is known as delayed (altered) —— eruption.
dentogingival junction (epithelial attachment). later migrates apically along the tooth to its normal position in which
the most apical cells of the JE are at the CEJ. A delay in this apical migration
is known as delayed (altered) passive eruption.
fertilization
Capacitation and acrosomal reaction of sperm.
entry of spermatozoa
Inhibition of polyspermy.
Acrosome reaction: Sperm releases enzymes to penetrate outer surface
of egg.
Cortical (zona) reaction: Sperm alters zona pellucida, preventing
other sperm from binding.
Meiosis II occurs in oocyte.
Barr body (second polar body).
Fusion of male and female pronuclei.
zygote
restoring diploids
BILAMINAR DISC
■ Occurs in the —- week.
■ Epiblast (primary ectoderm).
■ Amniotic cavity.
■ Ultimately gives rise to:
BILAMINAR DISC
■ Occurs in the second week.
■ Epiblast (primary ectoderm).
■ Amniotic cavity.
■ Ultimately gives rise to:
■ Ectoderm.
■ Mesoderm.
FETAL CIRCULATION
See Figure 4–12.
Oxygenated blood to heart via
Umbilical vein.
Inferior vena cava.
Foramen ovale
■ Allows most of the oxygenated blood to bypass the pulmonary circuit.
■ Pumps out the aorta to the head.
