DAT Embryology

Question 1

Fission

Answer 1

separation of an organism into
two new cells (amoeba)

Question 2

Budding

Answer 2

occurs when a new individual
grows from an existing one and then
splits off (hydra)

Question 3

Fragmentation + Regeneration

Answer 3

when a
single parent breaks into parts that
regenerate into new individuals (sponge/
planaria/starfish)

Question 4

Parthenogenesis

Answer 4

process in which egg
develops without fertilization, resulting in
an adult that is either haploid or diploid
(honeybees, wasps, ants, some lizards,
and hammerhead sharks)

Question 5

Ovary

Answer 5

• ova, or eggs, are produced here,
  and each female has two ovaries

Question 6

Oviduct (fallopian tube/uterine tube)

Answer 6

allows for eggs to move from the ovary
to the uterus, with one oviduct for each
ovary (2). Fertilization occurs here!

Question 7

Uterus

Answer 7

muscular chamber where
development of the embryo occurs until
birth. A fertilized ovum implants
(attaches) on the inside uterine wall, or
endometrium, on day 6 after fertilization

Question 8

Vagina

Answer 8

at birth, the fetus passes
through the cervix, an opening in the
uterus, and out of the body

Question 9

Testis

Answer 9

each consists of seminiferous
tubules for production of sperm, and
interstitial cells (Leydig cells) that
produce male sex hormones
testosterone and androgens at the
beginning of puberty. These hormones
are secreted in the presence of LH.

Question 10

Sertoli cells

Answer 10

are stimulated by FSH
and serve to surround and nurture
sperm, as well as secrete peptide
hormone inhibin, which acts on the
anterior pituitary to inhibit FSH
release

Question 11

Scrotum

Answer 11

testis are located here;
provides an external cavity, about
2o
C lower than the body
temperature, for sperm production.

Question 12

Epididymis

Answer 12

a coiled tube attached to
each testis that serves as the site for
final maturation and storage of sperm

Question 13

Vas deferens

Answer 13

transfers sperm from
one epididymis to the urethra

Question 14

Seminal vesicles

Answer 14

two glands that, during
ejaculation, secrete into vas deferens and
provide mucus (liquid for sperm), fructose
(energy for sperm), and prostaglandins
(stimulate uterine contractions that help
sperm move into uterus).

Question 15

Prostate gland

Answer 15

secretes milky alkaline
fluid into urethra and neutralizes acidity of
urine that may still be in the urethra, as
well as acidity of the vagina. This gland
also neutralizes seminal fluid, which is too
acidic from metabolic waste of sperm

Question 16

Bulbourethral (Cowper’s) glands

Answer 16

secrete small amount of thick mucus of
unknown function into urethra

Question 17

Sperm

Answer 17

are compact packages of DNA
specialized for effective male genome
delivery.

Question 18

parts of sperm

Answer 18

head, mid piece, tail

Question 19

Sperm head

Answer 19

haploid (23
chromosomes); at tip is acrosome, a
lysosome-like organelle containing
enzymes (hyaluronidase), which are
used to penetrate the egg. The
acrosome originates from Golgi body
vesicles that fuse together, and only
the nuclear portion of the sperm
enters the egg

Question 20

Mid-piece

Answer 20

flagellum (9+2
microtubule array) arising from one
member of centriole pair, and contains
lots of mitochondria

Question 21

Tail

Answer 21

remainder of flagellum; sperm is
propelled by whiplike motion of tail
and mid-piece

Question 22

Gametogenesis describes

Answer 22

the meiotic cell
divisions that produce eggs (oogenesis) and
sperm (spermatogenesis).

Question 23

Oogenesis

Answer 23

begins during the female
embryonic development (before birth).
Oogonia (fetal cells) undergo mitosis and
become primary oocytes. These primary
oocytes begin meiosis, but remain in
prophase I until puberty. During puberty,
one primary oocyte is selected and
stimulated via FSH to continue its
development through meiosis I during
the ~28 day menstrual cycle.

Question 24

Ovulation

Answer 24

releases the secondary
oocyte from a vesicular follicle, which
is stimulated by an LH surge. If this
oocyte is fertilized by a sperm, the
oocyte completes meiosis II, and the
resulting ovum/egg becomes diploid.
The polar body degenerates.

Question 25

Spermatogonia cells

Answer 25

undergo mitosis
and become primary spermatocytes.
These primary spermatocytes undergo
meiosis I and form two secondary
spermatocytes, which undergo meiosis
II to become four spermatids.

Question 26

Sertoli cells

Answer 26

are found in seminiferous
tubules, provide nourishment, and
“nurse” spermatids as they differentiate
into mature spermatozoa (sperm). The
sperm complete maturation (gain
motility and are stored) in the
epididymis.

Question 27

Semen

Answer 27

the combination of
spermatozoa and fluids that leave the
penis upon ejaculation.

Question 28

Capacitation

Answer 28

• the penultimate step in the
  maturation of the spermatozoa while in
  the vagina that allows for egg
  penetration. This is the final maturation of
  spermatozoa.

Question 29

Female reproductive cycle

Answer 29

consists of
ovarian cycle (in the ovary) and the
menstrual cycle (involves uterus)

Question 30

Menstrual cycle

Answer 30

is divided into the
proliferative, secretory, and
menstruation (menstrual flow)
phases. Menstruation begins with
the disintegration of the
endometrium (menstrual flow phase).

Question 31

steps of menstrual cycle

Answer 31

Hypothalamus and anterior
pituitary initiate, Follicle develops, LH surge, Development of endometrium, Corpus luteum disintegrates (no
longer maintained by LH)

Question 32

Ovarian cycle phases

Answer 32

Follicular phase, Ovulation, Luteal phase,

Question 33

Follicular phase

Answer 33

development
of egg and secretion of
estrogen from follicle [ends at
ovulation]

Question 34

Ovulation

Answer 34

mid-cycle release of
egg

Question 35

Luteal phase

Answer 35

secretion of
estrogen and progesterone
from corpus luteum after
ovulation [shedding of the
uterine lining lasting
approximately 5 days]

Question 36

progesterone serves to…

Answer 36

develop and maintain the endometrial wall. also inhibits lactation during pregnancy

Question 37

Female hormonal contraception

Answer 37

estradiol and/or progesterone are
spiked artificially high → negative
feedback suppresses LH/FSH surge
→ no ovulation can occur → no
fertilization possible

Question 38

Male contraception

Answer 38

a pill would
interfere with LH and FSH to
decrease sperm production