Midterms Lec 2/2 Flashcards
the branch of biology that studies the prenatal
development of gametes (sex cells),
fertilization, and development of embryos and
fetuses
embryology
number of chromosomes in a haploid
23
number of diploid chromosomes
46
“Ontogeny
recapitulates phylogeny
Ernst Haeckel
theorizes that the stages an
animal embryo undergoes
during development are a
chronological replay of that
species’ past evolutionary
forms.
Ernst Haeckel
Recapitulation is
not the only relationship between
embryos and ancestors.
Gavin de Beers
Embryonic structures may or
may not be present from their
ancestors or descendants.
t/f
true
vestigial
(lost); or retained to adulthood.
embryonic structures
Developmental stages may be
repeated in later stage but not
in earlier stages.
t/f
false
Developmental sequence may or
may not be altered in the
descendant
t/f
t
are an organism’s reproductive
cells or sex cells.
gametes
are haploid cells, and each cell
carries only one copy of each
chromosome
gametes
– process
of formation of gametes.
gametogenesis
produces testosterone in the presence of
luteinizing hormone (LH).
leydig cells
s a “nurse” cell of a seminiferous tubule and
helps in the process of spermatogenesis
sertoli cells
is the final stage of spermatogenesis,
which sees the maturation of spermatids into mature
spermatozoa
spermiogenesis
– an endocrine structure that
continuously release hormones responsible for the
thickening of the endometrium in the uterus.
corpus luteum
- Is the fusion of haploid gametes, egg and sperm, to form the
diploid zygote
fertilization
- Also known as cellulation (the
formation of the blastomeres).
cleavage
- The process by which the
zygote undergo repeated
mitotic cell division.
cleavage
- is a mass of 16
totipotent cells in a spherical
shape
morule
spherical layer
of cells (the blastoderm)
surrounding a fluid-filled or
yolk-filled cavity (the
blastocoel).
blastula
EPIBLAST or
EPIMERE; developing embryo
nourished by the vegetal pole
(dorsal cells–ECTODERM)
animal pole
– HYPOBLAST or
HYPOMERE or developing yolk;
nourishes the embryo GUT
(ventral cells–ENDODERM)
vegetal pole