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Reproduction

Terms in this set (76)

internal fertilization
sperm is deposited inside female body. sperm ferittlize the egg inside females body.
dioecious
males and females. difference between the two is the sex organ and gamete that is produced. only one set of reproductive organ exists on an individual.
monotremes
lay eggs, incubate young, possess cloaca, only left ovary functional, mammary glands without nipples
marsupials
possess cloaca, inefficient placenta, short gestation, prolonged nursing, possess marsupium
inefficient placenta
limited connection between maternal blood supply and fetal blood supply. not a direct connection
short gestation
produce poorly developed young, altricial young --> very poorly developed and take a long time to develop
marsupium
pouch
eutherians
developed placenta, longer gestation, shorter nursing
eutherians: developed placenta
internal fertilization, development inside uterus, more efficient contact, fully developed young
eutherians: shorter nursing
give birth to precocial young, more developed and require longer gestation but trade off is that they require shorter nursing outside of mothers body
marsupial gestation period
10 days
elephant gestation period
650 days
monotremes don't have a ______ period
gestation
shortest and largest lactation periods
eutherians (4-900 days)
lactation period is shorter for eutherians than marsupials
if we take it from perspective of long developmental stage
hooded seal lactation period
4 days, has to develop rapidly after that
1-28 young per litter
Manny mammals only have 1 young, average is 1-15, naked mole rat can have lots of young in litters (28)
birth intervals
3 week (rats)-4 year(rhino)
bulbourethral glands
secrete a very thick mucus-like secretion, eliminates any crystals of urine that were left. acts as a lubricant, early sexual arousal
preputial glands
muscular gland, exocrine gland located in front of genitals, produces pheromones, communicating channel
ampullary glands
glandular part of ductus in some species, secrete lipids and glycogen, energy sources for sperm
copulating glands
when male is finished copulating, he leaves a sperm plug. blocks the opening and prevents another male from mating with the female.
erectile tissue
spongy epithelial tissue, blood vessels supplying this tissue will dilate, more blood being delivered. arteries dilate, veins compress. 3 units of erectile tissue: ones surrounding arteries
glans penis
head of penis, where urethral opening is
baculum
complex bony structure that runs along the penis, doesn't need as much erection because a bone is inserted
spermatogenesis
sperm production
seminiferous tubules
in testes, at outer edge we have a lot of cells called germinole cells (spermatogonia) diploid cells when stimulated (by testosterone) they start to go through division, first mitosis then meiosis and produce spermatozoa.
four gametes produced. genetically different from one another.
spermatozoa are in tubule and then move through fluid and propelled to where they get stored in epididimis
nurse cell
prevent the immune system from attacking these things. create fluid that allows this to move through the epididimys
if we have old sperm
nurse cells will secrete a hormone that shuts down the process that gets rid of these sperm and keep the newer or fresher more viable sperm in epididymis
leydig cells
interstitial cells, testosterone producers
ovaries
always inside abdominal cavity, eggs are surrounded by protective cells that are converted into ovarian follicles
oviducts
ovaries release a gamete (ovulation), females system is not directly connected to tube that is carrying things, gamete has to find its way into tubule (oviduct)
Where does fertilization occur?
oviduct
uteri
uterus
vagina
isn't a true vagina in monotremes or marsupials. have a cloaca cavity. eutherians have a vagina
marsupials have a didelphis (paired or forked) penis for male is also forked. more developed than monotremes but not actually a vagina.
monotremes, common urogenital sinus.
cervix
neck of uterus, diameter gets bigger during ovulation, mucus in opening and thins when sexually receptive, mucus is otherwise preventing sperm and bacteria and yeast from getting inside
external genitalia
labia majora and minora, clitoris
os clitoris
bone that makes it rigid, debatable function: sensitivity, muscular contractions
duplex uterus
two separate uteri, each uterus has a cervix

lagomorphs, rodents hyrax
bipartite uterus
two separate uteri but there is only one cervix

whales and most carnivores
bicomate uterus
uterine horn connect have a y shape. separate medial but fuse distally, single cervix, most common

bats, elephants, ungulates, primates
simplex uterus
no separation at all, two uterine horns, two oviducts merge into a common chamber

anteaters, sloths, higher primates, some bats
formation of placenta
1. Blastocyst implants in uterine wall
-implantation
-endometrium is thickened and developed.
2. Blastocyst differentiates into embryo and trophoblast
3. Trophoblast produce enzymes
4. Enzymes break down decidua
-decidua → mucosa lining the uterus
5. Trophoblast sinks in endometrium
6. Trophoblast thickens and extends villi
-villi are site of cappillaried from baby and embryo are in close contact with capilarries from mother and this is where exchange occurs
functions of placenta
1. Anchors fetus to uterus
2. Transports nutrients from mother to fetus
3. Accepts fetal wastes
4. Produces hormones
-continue develpment of fetus, lack of hormones signals birth to occur
5. Suppresses maternal immune activity
metatherian placentae: nonvascular choriovitelline
yolk sac connected to endometrial mucosa. very inefficient, little attachment from fetus directly but to the yolk sac. embryo gets most nutrients from yolk sac, not mother
metatherian placentae: vascular choriovitelline
highly vascularized yolk sac connected to endometrial mucosa, more efficient than nonvascular
metatherian placentae: apposed (nonvascular) chorioallantoic
yolk sac is primary exchange surface, but allantois also attached, increase efficiency a little bit, reduce amount of yolk
metatherian placentae: syncytialized (vascular) chorioallantoic
greater exchange across allantoic membranes, diffusion makes this work, most similar to eutherian placenta
eutherian placentae: diffuse
villi scattered evenly throughout uterus, more exchange than metatherians
eutherian placentae: cotyledonary
evenly spaced patches of villi
eutherian placentae: zonary
continuous band of villi
eutherian placentae: discoidal
villi in 1-2 disc-shaped areas, where the exchange happens
epitheliochorial
most material that has to be crossed, 6 tissue layers, limited attachment between villi and uterine wall, minimal bleeding, placenta isn't shed after birth
syndesmochorial
5 layers, maternal epithelium is lost
hemochorial
direct contact between villi on embryo and maternal blood supply
endothelioendothelial
fetal and maternal capillaries in direct contact
hemoendothelial
fetal capillaries bathed in maternal blood, common for discoidal placenta. baby born and placenta is expelled out of uterus
placental scar
this female had already given birth. see reproductive history
if no scars, never been inseminate → nulliparous
if one scar → has had one offspring, parous
if multiple scars → many different reproductive events → multiparous
prevention of immunorejection: marsupials
eggshell membranes present in early gestation
prevention of immunorejection: eutherians
no eggshell membranes, zona pellucida in early gestation, trophoblast and decide in later gestation
marsupials have
short gestation, altricial young, longer lactation
eutherians have
longer gestation, precocial young, shorter lactation
delayed fertilization
-ovulation has occurred but sperm are stored inside the females body and sperm can then fertilize that ovulated egg.
-secondly, ovulation is delayed without sperm stored.
-bats are the only mammal that display this, common for bats in seasonal environments
-allows them to time the birth if their young with the optimal availability of their food.
delated development
only bats do this
get to production of blastocyst, implants into uterian horn or uterus, but then development is going to slow down.
time the delivery of baby with food availability so that the two things coincide with one another.
delayed implantation
normal fertilization, blastocyst becomes arrested and floats freely without implanting. once environmental conditions become favorable, then it will implant.
armadillo always does this.
often animals that produce large litters
bears
embryonic diapause
fertilization occurs, cleavage begins, blastocyst goes into state of dormancy where it stops dividing. won't resume until it receives an endocrine signal.
endocrine signal
common in kangaroos, linked to development of siblings. environmental conditions do play a role.
cortisol and birth
a hormone that's released by the adrenal gland.
released by the fetus at the end of gestation
embryo is stressed and triggers production of cortisol by the fetus. that then interacts with placenta and stops placenta from producing estrogen and progesterone
prostaglandins and birth
placenta produces this, initiate contractions of smooth muscle in the uterus. push fetus towards the cervix. puts pressure on cervix. pressure creates a signal that goes to posterior pituitary that releases oxytocin
oxytocin and birth
stimulates stronger uterine smooth muscle contractions, more pressure, more oxytocin. positive feedback loop. increase in smooth muscle contractions. linked with labor
linked to let down of milk by mammary glands. its release, not production.
relaxin and birth
corpus ludium → hormone producing structure, produces estrogen and progesterone. causes uterus to be maintained and development of placenta. produce until placenta is ready to take over.
produces relaxin → soften ligaments in pelvis.
allows more space for birthing to happen
estradiol and lactation
secreted by placenta, amt increases. cause mammary glands to enlarge. contnuie to be secreted until the end of gestation, decrease at partrision. as they decrease. anterior pituitary produces prolactin
progesterone and lactation
secreted by placenta
prolactin and lactation
hormone that stimulates the production of milk. near the end of gestation at birthing process, we get pulses and releases of prolactin that produces milk
oxytocin
promotes the let down of milk.
suckles stimulates nerve receptors in nipple, sent to hypothalamus, release more oxytocin.
causes the continuation of both oxytocin and prolactin. as long as mother is nursing causes the release of hormones that cause production and release of milk
oxytocin and prolactin in lactation
promote maternal behavior
still maintains strong contact with baby because hormones keep maternal behavior.
benefits of milk
nutrion, passive immunity, symbiotic intestinal flora
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