Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
81 Cards in this Set
- Front
- Back
|
gonads
|
the primary reproductive organs, location of gamete production (male = testes, female = ovaries)
|
|
|
testes
|
male gonads; contain two functional components - the seminiferous tubules and the interstitial cells
|
|
|
seminiferous tubules
|
location of sperm production, where they are nourished by Sertoli cells
|
|
|
interstitial cells
|
located between the seminiferous tubules; secrete testosterone and other androgens
|
|
|
androgens
|
male sex hormones
|
|
|
scrotum
|
an external pouch surrounding the testes which maintains a teste temperature about 2-4*C lower than body temperature (essential for sperm survival)
|
|
|
epididymis
|
coiled tubules in which sperm acquire motility, mature, and are stored until ejaculation
|
|
|
ejaculatory route of sperm
|
from the epididymis, sperm travel through the vas deferens to the ejaculatory duct and then to the urethra
|
|
|
seminal fluid
|
aids in sperm transport by lubricating the passageways through which sperm will travel; produced by three glands - the seminal vesicles, the prostate gland, and the bulbourethral glands
|
|
|
seminal vesicles
|
secrete a fructose-rich fluid that serves as an energy source for highly active sperm
|
|
|
prostate gland
|
releases an alkaline milky fluid that protects the sperm form teh acidic envrionment of the female reproductive tract
|
|
|
bulbourethral glands
|
secrete a small amount of viscous fluid prior to ejaculation (function unknown)
|
|
|
semen
|
sperm + seminal fluid
|
|
|
spermatogenesis
|
sperm production, occurs in the seminiferous tubules: spermatogonia (2N) -- primary spermatocytes (2N) -meiosis I -- secondary spermatocytes (N) -meiosis II -- spermatids (N) -maturation -- spermatozoa (N)
|
|
|
name of mature sperm cells
|
spermatozoa, an elongated cell with a head (almost entirely nucleus), neck and body (mitochondria), and tail/flagellum
|
|
|
acrosome
|
a cap-like structure derived from the Golgi apparatus that develops over the anterior half of the head; contains enzymes needed to penetrate the tough outer covering of the ovum
|
|
|
rate of spermatogenesis
|
(after sexual maturity) about 3 million primary spermatocytes begin to undergo spermatogenesis every day; the maturation process takes a total of 65-75 days
|
|
|
ovaries
|
female gonads; produce ova and secrete estrogen and progesterone; consist of thousands of follicles
|
|
|
ovarian follicle
|
a multi-layered sac of cells that contains, nourishes, and protects an immature ovum; also produce estrogen
|
|
|
cervix
|
the lower, narrow end of the uterus, connecting to the vaginal canal
|
|
|
oogenesis
|
production of female gametes: primary oocytes (2N) -meiosis I, once per month -- secondary oocyte (N) -expelled from the follicle during ovulation- and a polar body. Meiosis II does not occur until fertilization.
|
|
|
oocyte
|
cell membrane is surrounded by two layers = zona pellucida (inner) and corona radiata (outer); penetration of these layers triggers Meiosis II, which yields a mature ovum and another polar body.
|
|
|
menarche
|
the first time a female gets her period
|
|
|
menopause
|
ovaries become less sensitive to the hormones that stimulate follicle development (FSH and LH) and eventually they atrophy; the remaining follicles disappear, estrogen and progesterone levels greatly decline, and ovulation stops.
|
|
|
fertilization - where, when
|
can occur 12-24 hours following ovulation, in the the lateral, widest portion of the fallopian tube; sperm remain viable and capable of fertilization for 1-2 days following intercourse.
|
|
|
fertilization - how
|
sperm secretes enzymes to penetrate the corona radiata, but the acrosome is responsible for penetrating the zona pellucida; once in contact with the ovum cell membrane, the sperm forms the acrosomal process and the sperm nucleus enters the ovum's cytoplasm (the ovum now completes meiosis II)
|
|
|
acrosomal process
|
a tube-like structure that extends to the cell membrane of the ovum and penetrates it, fusing the sperm cell membrane with that of teh ovum
|
|
|
cortical reaction
|
triggered by the acrosomal rxn, calcium ions are released into the cytoplasm of the ovum, initiating a series of rxns that result in the formation of the fertilization membrane; also stimulates an increase in metabolic rate
|
|
|
fertilization membrane
|
a hard layer that surrounds the ovum cell membrane and prevents multiple fertilization (triggered by the cortical rxn)
|
|
|
monozygotic twins
|
or identical twins, a result of a single zygote splitting into two embryos; if this occurs at the 2-cell stage, the embryos will have separate chorions and separate placentas... if it occurs at the blastula stage, the embryos will have only one chorionic sac, and will share a placenta and possibly an amnion.
|
|
|
dizygotic twins
|
a result of two ova being released in one ovarian cycle and fertilized by two different sperm - the two embryos implant in the uterine wall individually, each develops its own placenta, amnion, and chorion (although the placentas may fuse if the embryos implant very close to each other)
|
|
|
cleavage (development)
|
a series of rapid mitotic divisions that lead to an increase in cell number without a corresponding increase in cell protoplasm (i.e. volume) = increases ratio of nuclear-to-cytoplasmic material and surface area-to-volume (improves gas and nutrient exchange)
|
|
|
indeterminate cleavage
|
cleavage that results in cells that maintain the ability to develop into a complete organism (identical twins are the result of an indeterminate cleavage)
|
|
|
determinate cleavage
|
results in cells whose future differentiation pathways are determined at an early developmental stage.
|
|
|
timing of first cleavages
|
1st occurs about 32 hours after fertilization; 2nd = 60 hours; 3rd = 72 hours
|
|
|
when does embryo reach uterus?
|
at 8 cells, about 72 hours after fertilization
|
|
|
morula
|
a solid ball of embryonic cells
|
|
|
blastulation
|
development of a blastocoel by the morula, eventually to become the blastula (day 4)
|
|
|
blastocoel
|
a fluid-filled cavity that develops via blastulation
|
|
|
the mammalian blastula
|
blastocyst = consists of two cell groups, the inner cell mass (protrudes into the blastocoel) and the trophoblast (surrounds the blastocoel and later gives rise to the chorion)
|
|
|
implantation
|
the embryo implants in the uterine wall during blastulation, approximately 5-8 days after fertilization; uterus is prepared for implantation by the hormone progesterone which causes glandular proliferation in the endometrium; the embryonic cels secrete proteolytic enzymes that enable the embryo to digest tissue and implant itself in the endometrium.
|
|
|
endometrium
|
the mucosal lining of the uterus
|
|
|
ectopic pregnancy
|
implantation of the embryo outside of the uterus, most often occuring in the fallopian tube
|
|
|
gastrula
|
a three-layered structure formed (after implantation) by cell migration of the single cell layer blastula.
|
|
|
two-layered gastrula
|
invagination forms the ectoderm, endoderm, archenteron, and blastopore
|
|
|
archenteron
|
the cavity formed by gastrulation; opening is called the blastopore
|
|
|
fate of the blastopore
|
if anus, deuterostomes; if mouth, protostomes
|
|
|
third cell layer of the gastrula
|
mesoderm = formed by proliferation and migration of cells into the space between the ectoderm and endoderm
|
|
|
three primary germ layers
|
ectoderm, endoderm, mesoderm
|
|
|
future of the ectoderm
|
integument (epidermis, hair, nails, and epithelium of the nose, mouth, and anal cavity); lens of the eye; the nervous system
|
|
|
future of the endoderm
|
epithelial lining of the digestive and respiratory tracts (including lungs); parts of the liver, pancreas, thyroid, and bladder
|
|
|
future of the mesoderm
|
musculoskeletal system, circulatory system, excretory system, gonads, connective tissue through body, and portions of digestive and respiratory organs
|
|
|
induction
|
influence of a specific group of cells (sometimes called the organizer) on the differentiation of another group of cells; most often mediated by chemical substances (inducers) passed from the organizer to adjacent cells.
|
|
|
neurolation
|
at the end of gastrulation, regions of the germ layers begin to develop into a rudimentary nervous system = notochord has an inductive effect on the overlying ectoder, causing it to bend inward and form a groove along the dorsal surface of the embryo; neural folds grow upward and fuse to form a closed tube = the neural tube.
|
|
|
notochord
|
a rod of mesodermal cells that develops along the longitudinal axis just under the dorsal layer of ectoderm; induces development of neural folds -- neural tube
|
|
|
neural tube
|
formed from the dorsal ectoderm, this gives rise to the brain and spinal cord; once it is formed it detaches from the surface ectoderm
|
|
|
neural crest cells
|
the cells at the tip of each neural fold; they migrate laterally and give rise to many components of the peripheral nervous system including the sensory ganglia, autonomic ganglia, adrenal medulla, and Schwann cells
|
|
|
fetus
|
name of the embryo after 8 weeks of gestation
|
|
|
extra-embryonic membranes
|
amnion, chorion, allantois, and yolk sac
|
|
|
amnion
|
a thin, tough membrane containing a watery fluid called amniotic fluid (acts as a shock absorber of external and localized pressure from uterine contractions during labor)
|
|
|
chorion
|
a membrane that completely surrounds the amnion; develops chorionic villi about 2 weeks after fertilization
|
|
|
chorionic villi
|
villi extending from the chorion into the uterine wall where they become closely associated with endometrial cells and develop into the spongy tissue of the placenta.
|
|
|
allantois
|
develops as an outpocketing of the gut; its blood vessels enlarge and become the umbilical vessels
|
|
|
umbilical vessels
|
develop from enlarged vessels of the allantois, and connect the fetus to the developing placenta
|
|
|
yolk sac
|
site of early development of blood vessels, becomes associated with the umbilical vessels, and is eventually enveloped (with the allantois) by the amnion to for the primitive umbilical cord
|
|
|
umbilical cord
|
the connection between the fetus and placenta; formed by the yolk sac and allantois, which are then enveloped by the amnion. At maturity, the cord consists of umbilical vessels (allantois), surrounded by a jelly-like matrix.
|
|
|
placenta
|
site of nutrition, respiration, and waste disposal for the fetus; also acts as an endocrine gland, producing the hormones progesterone, estrogen, and HCG
|
|
|
HCG
|
human chorionic gonadotropin (presence in urine indicates pregnancy)
|
|
|
fetal circulation
|
umbilical vein carries oxygenated blood from the placenta to the fetus -- ductus venosus -- inferior vena cava -- right atrium (mixed with blood from supieror vena cava) -- 1) foramen ovale -- left atrium -- left ventricle -- aorta -- system/umbilical artery; or 2) right ventricle -- pulmonary artery -- ductus srteriosus -- aorta; or 3) right ventricle -- pulmonary artery -- pulmonary vein -- left atrium, left ventricle, aorta, system/umbilica artery
|
|
|
ductus venosus
|
a shunt that allows oxygenated blood to bypass the fetal liver; degenerates after birth, closing completely by 3 months
|
|
|
foramen ovale
|
a shunt that diverts blood away from the pulmonary arteries, by moving blood from the right atrium to the left atrium (instead of to the right ventricle)
|
|
|
ductus arteriosus
|
a shunt that directs blood from the pulmonary artery to the aorta; constricts after birth and eventually closes permanently
|
|
|
arteries carry oxygenated blood except...
|
the fetal umbilical artery and the adult pulmonary arteries
|
|
|
veins carry deoxygenated blood except...
|
the fetal umbilical vein and the adult pulmonary veins
|
|
|
patent ductus arteriosus
|
PDA = occurs if the ductus arteriosus does not close after birth
|
|
|
changes to the circulatory system after birth
|
1) resistance in pulmonary blood vessels decreases = increased blood flow thru lungs; 2) stop of umbilical blood flow decreases blood pressure in the inferior vena cava = decreased pressure in the right atrium; 3) increased blood flow from lungs = increased pressure in left atrium; 4) decreased RA pressure and increased LA pressure = closed foramen ovale
|
|
|
1st trimester
|
major organs develop (heart, then eyes, gonads, limbs, and liver); cartilaginous skeleton begins to turn into bone by the 7th wk; by the end of 8 wks, most of organs have formed, brain is fairly developed; at end of third month the fetus is about 9 cm long.
|
|
|
first heart beat
|
at approximately 22 days
|
|
|
2nd trimester
|
lots of growing; fetus begins to move around, face appears human, and toes/fingers elongate; at end of 6 months, the fetus is 30-36 cm long.
|
|
|
3rd trimester
|
continued rapid growth and further brain development; during 9th mo, antibodies are transported by highly selective active transport from mother to fetus
|
|
|
stages of labor
|
1) cervix thins out and dilates, amniotic sac ruptures, mild contractions; 2) rapid contractions resulting in birth of baby and cutting of umbilical cord; 3) uterus contracts, expelling the placenta and umbilical cord
|
