Puri-ppt 3: Spermatogenesis, Fertilization, Embryonic Dev. And Birth Flashcards
1
Q
Location of spermatogenesis
A
Seminiferous tubules
2
Q
List the 3 differentiation steps in spermatogenesis
A
- formation of acrosome
- development of flagella and mitochondrial powerhouse
- DNA condensation
3
Q
Formation of acrosome
A
- one of spermatogenesis steps
- acrosome contains hyluronidase and acrosin that are likely to help sperm break thru zona pellucida
4
Q
Development of flagella and mitochondrial powerhouse
A
- development of mitochondria and flagella help w/ sperm’s motility
5
Q
DNA condensation
A
- conversion of DNA into inactive state, prevents DNA damage
- Histones replaced w/ protamine
6
Q
Caput sperm
A
- Immotile
(Caput=head; immature at head)
7
Q
Caudal sperm
A
- motile
(at end of epididymis)
8
Q
Flow of sperm
A
- immediate transport
- cervix
- uterus
- oviduct
- fertilization
9
Q
Immediate transport
A
- retrograde loss
- phagocytosis
- entrance to cervix/uterus
10
Q
Cervix
A
- removes non-motile and abnormal sperm
11
Q
Uterus
A
- initiation of capacitation
- phagocytosis
12
Q
Oviduct
A
- completion of capacitation
- hyperactive motility
13
Q
Fertilization
A
- acrosome rxn
- sperm penetrates oocyte
- male and female pronuclei form
14
Q
Epididymal sperm
A
- membrane has complement of surface proteins and carbs
15
Q
Ejaculated sperm
A
- made of epididymal sperm + seminal plasma
- surface proteins and carbs get coated w/ seminal plasma that mas parts of membrane proteins
16
Q
Capacitated sperm
A
- ejaculated sperm + female tract
- in the female repro. Tract, seminal plasma coating and some surface molecules removed, exposing parts of molecules that bind to ZP
17
Q
Hyperactivated motility
A
- helps cumulus cells disperse and sperm to break thru ZP
- high amplitude and asymmetrical beat pattern
18
Q
Absence of hyperactivated mtoility
A
- low amplitude and symmetrical
19
Q
Before membrane fusion
A
Sperm breaks thru ZP and reaches perivitelline space
20
Q
During membrane fusion
A
Plasma membrane of oocyte fuses w/ equatorial segment & engulfs fertilizing spermatazoa
- cortical granules released and prevent other sperm from binding (cortical rxn)
21
Q
After membrane fusion
A
- sperm nuclear membrane disappears and nucleus decondenses
22
Q
Events that happen if no conceptus present
A
- secretion non-existent during first half of luteal phase
- development of oxytocin receptors and release of oxytocin by large luteal cells binds to otr causing PGF2-alpha synthesis
- PGF2-alpha synthesis causes luteolysis
23
Q
If fertilization occurs
A
- conceptus inhibits oxytocin synth, preventing PGF2-alpha synthesis and luteolysis
- CL continues to secrete progesterone
24
Q
IFN-tau
A
- released by early embryo
- blocks oxytocin receptor expression and PGF2-alpha synthesis
25
4 steps that must happen before embryo can attach to uterus
- dev. Of embryo within ZP
- hatching of blastocyst from ZP
- maternal recognition of pregnancy
- formation of yolk sac, amnion, chorion, and allantois
26
Allantochorion
- Interacts w/ endometrium and generate cotyledons
27
Cotyledon-caruncle complex
Placentome
28
Placenta function
- metabolic exchange
- elimination of waste products
- gas exchange
- thermoreg.
- endocrine organ during pregnancy
29
PMSG
FSH-like, for super ovulation & prev. of follicular atresia
30
How placenta acts like an endocrine organ during pregnancy
- placenta secretes eCG/PMSG to maintain CL
- placenta maintains progesterone levels
- secretes estradiol
- secretes placental lactogen
- source of relaxin
31
____ and ____ secrete progesterone
CL and placenta
32
Stopping secretion of progesterone does what?
Terminates pregnancy
33
Estradiol
- secreted by placenta
- role in parturition induction
34
Placental lactogen
- similar to GH
- lactogenic effects
35
Relaxin
- causes pelvic ligaments to soften and relax so fetus can be expelled
36
When does placenta take over progesterone secretion in sheep and cattle
- sheep: after day 50
- cattle: 6th-8th months of gestation
37
3 stages of parturition
- myometrial contractions start due to drop in progesterone
- expulsion of fetus due to strong myometral and abdominal contractions
- expulsion of fetal membranes
38
Hormones that terminate pregnancy
- stopping progesterone secretion
- giving PFG2-alpha
39
How birth causes myometrial contractions
- fetus moving through birth canal causes pressure on cervix
- paraventricular nucleus of hypothalamus is stimulated and secretes oxytocin
- oxytocin -> myometral contractions
