Reproduction Flashcards
(92 cards)
1
Q
reproduction
A
propagation and continuation of the species
2
Q
parturition
A
birth
3
Q
puberty
A
reproductive maturation
- physical - reproductive organs
- endocrine - endocrine cycle develops
4
Q
heat/ estrus
A
period of sexual receptivity
5
Q
estrous cycle
A
interval from one heat to the next heat
6
Q
ovulation
A
release of oocyte from ovary
7
Q
spermiation
A
release of spermatozoa into male duct system
8
Q
copulation
A
transfer of sperm from male to female
9
Q
fertilization
A
union of the male (sperm) and female (oocyte) gametes
10
Q
pregnancy/ gestation
A
development of the zygote/ embryo/ growth of fetus
11
Q
lactation
A
nourishment of neonate
12
Q
ovaries
A
female gonad (sex organ) structure which contains all the follicles from which oocytes are released
13
Q
infundibulum
A
catches egg when it is released from the ovary
14
Q
oviduct
A
fallopian tube
tube for egg transportation to the uterus
site of fertilization
15
Q
uterus
A
the place where the fetus(s) develops
provides nutrients prior to development of the placenta
contracts during parturition to expel the fetus
16
Q
cervix
A
fibrous connective tissue
barrier to external environment
acts as a passageway and filter for sperm
dilates at parturition
17
Q
vagina
A
copulatory organ
passageway btwn cervix and external genetalia (vulva)
passageway for the fetus
18
Q
vulva
A
external genetalia
includes labia which help protect vagina from bacterial contamination
19
Q
ovarian cycle
A
primary follicle
secondary follicle
tertiary (antral) follicle
corpus luteum
20
Q
primary (primordial) follicle
A
immature oocyte surrounded by a single layer of granulosa cells
21
Q
secondary (growing) follicle
A
recruited from primordial pool
2 or more layers of granulosa cells
22
Q
tertiary (mature) or antral follicle
A
antrum is visible
23
Q
corpus luteum
A
develops from follicle after ovulation
-yellow mass of cells that fills the ruptured follicle
granulosa and theca cells become luteal cells
produces progesterone - necessary for the maintenance of pregnancy
in most species CL degenerates @ end of cycle unless gets signal from uterus that embryo is present
24
Q
oogenesis
A
egg production
production of primary oocytes occurs before birth
females complement of oocytes is fixed soon after birth
100,000s of primordial follicles each containing an oocyte
only a relative few will be ovulated - most partially develop and become atretic
25
zona pellucida
protein coat "shell" that surrounds the oocyte
26
follicle
blister like structure on the ovary
contains an oocyte
contains granulosa cells that produce estrogen
27
corpus albicans
"scar" left on ovary after CL regresses
28
ovarian cycle of a uniparous species
usually produce 1 mature ovum per estrous cycle
| ex. horse, cow, human
29
ovarian cycle of a multiparous species
(ie litters)
multiple ova produced per estrous cycle
ex. cat, dog, sow
30
estrous cycle
time from beginning of one heat period (estrus) to the next
| stages: proestrus, estrus (high estrogen), metestrus, diestrus (high progesterone), anestrus (only some species)
31
proestrus
follicles begin developing and growing
| output of estrogen from follicles increases accordingly
32
estrus
day 0 of cycle
period of sexual receptivity in the female
estrogen level production peaks
ovulation occurs near end of estrus
33
metestrus
corpus luteum developing
estrogen dropping rapidly
progesterone rising rapidly
34
diestrus
CL exerting maximum effect
the uterus preps for an embryo
if fertilized ovum implants, CL is retained
if no pregnancy, CL degenerates
35
anestrus
period of temporary ovarian inactivity
seen in animals that have seasonal cycles
also seen during periods of nutritional stress
36
estrous cycle intervals
polyestrous
seasonal polyestrous
diestrous
monoestrous
37
polyestrous
cycle continuously throughout the year if they are not pregnant (cattle, swine, human)
38
seasonally polyestrous
seasonal variations in estrous cycles (horse, sheep, cat)
39
diestrous
2 cycles/ year, usually spring and fall (dog)
40
monoestrus
one cycle per year (fox and mink)
41
endocrine regulation of female cycle
initiation by the hypothalamus in the brain
releases gonadotropin(GnRH)
responds to environment (some species; day length)
responds to body maturity (puberty)
often inhibited by nutritional stress
- early lactation, (also athletic training)
inhibited by progesterone (ie birth control)
42
gonadotropin releasing hormone
| GnRH
stimulates anterior pituitary gland to produce gonadotropin hormones
- follicle stimulating hormone (FSH)
- leutinizing hormone (LH)
- they travel in blood to the gonads
43
follicle stimulating hormone
stimulates follicle development
44
hypothalimc - pituitary - ovarian axis
mature follicle --> estrogen --> GnRH --> LH --> ovulation
mature follicles produce lots of estrogen
estrogen level reaches high threshold
causes a surge in GnRH production
causes surge in LH release from pituitary
causes ovulation
ovulated follicle becomes CL producing high P4
high P4 low E2 = neg feedback
high E2 low P4 = positive feedback
-causes LH surge
45
prostaglandin (PGF2)
produced by non-pregnant uterus
| causes lysis of CL
46
lysis of corpus luteum
```
if animal is not pregnant
turns into corpus albicans
loss of CL causes progesterone levels to decrease
new follicles mature quickly
ovulation occurs thus completing a cycle
```
47
pregnancy: maintenance of the corpus luteum
embryo moves to uterus for implantation
embryo makes placenta
-membranes which surround the fetus and help w/ nutrient exchange w/ mother
-may make progesterone and other hormones
48
signs of estrus - dairy
standing for mounting or chin pressing
49
reproductive physiology of the bitch
```
one estrus per breeding cycle (monoestrus)
one breeding cycle every 6 to 8 months
-not related to season
anestrus - proestrus - estrus - diestrus
corpus luteum for aprox 65 days (preg or not)
-no maternal recognition of pregnancy
estrus for approx 10 days
ovulation (multiple) at approx day 7
-2 days after LH surge
```
50
reproductive physiology of the queen
polyestrus (3 week cycles)
-induced ovulator
-alternate proestrus - estrus - postestus until mating
no mating - no ovulation - no CL - no rise in progesterone
51
male reproductive system
produces testosterone
spermatozoa
delivers spermatozoa to the female system
52
testes
suspended in scrotum
cooler temperature required for sperm production
descend through inguinal canal into scrotum before birth
develop in abdominal cavity during fetal development
53
cryptochid
lack of testicular descent
sterile
still produce testosterone
54
pampiniform plexus
countercurrent heat exchanger (of scrotum/testes)
55
sperm pathway
```
seminferous tubules - continually produce sperm
rete testis
epididymis (head, body, and tail)
vas deferens (ductus deferens)
urethra
```
56
seminiferous tubules
between tubules:
-leydig cells - produce testosterone
w/in tubules
-sertoli cells - support development of spermatozoa
57
spermaition
```
release of spermatozoa into tubule
spermatogonia
--> proliferation
spermatocyte
--> meiosis
spermatid
--> final differentiation
spermatozoa
```
58
sperm anatomy
head - contains nucleus of the cell, covered by acrosome
midpiece - large concentration of mitochondria
tail - contractile fibrils (flagella)
59
acrosome
covers sperm head
| contains enzymes that help the spermatozoa penetrate the zone pelucida
60
semen
seminal plasma and spermatozoa
| billions of spermatozoa/ mL of semen
61
seminal plasma
fluid produced by epididymis and accessory sex glands
| provides nutrients and buffer
62
accessory reproductive glands
seminal vesicles - paired glands
prostate gland - single gland surrounds urethra
bulbourethra (coupers) gland - secrete mucinous fluid just before ejaculation that clears and lubricates the urethra
63
endocrine regulation in male
negative feedback loop
| GnRH -+-> LH -+-> leydig cell --> testosterone - - -> GnRH
64
delivery of sperm to oocyte
```
sperm transported from vagina to oviduct by
- swimming
- contractions of uterus and oviducts
-cilia in oviducts
arrives in the oviduct in minutes
```
65
acrosome reaction
occurs when sperm binds to zona pellucid
| release of acrosomal enzymes to help the sperm penetrate through the zona pellucida
66
fertilization
a single sperm penetrates the zone and fuses w/ the cell membrane of the ovum
this leads to the "zona block" which prevents any other sperm from getting through
this is due to the cortical reaction occurring in the oocyte
-blocks polyspermy
67
cortical reaction
"zona block"
occurs after fusion of sperm and oocyte membranes
contents of oocyte's cortical granules are exocytosed into perivitine space and cause a hardening of the zona
polyspermy is thus prevented
68
zygote
a diploid cell resulting from the fusion of 2 haploid gametes; a fertilized ovum
69
morula
a solid ball of cells resulting from division of a fertilized ovum, from which a blastula is formed
70
blastocyst
a blastula (hollow ball of cells) in which some differentiation of cells has occurred
71
blastocoel
fluid filled cavity of a blastula
72
placenta
multilayered (3 layers), fluid filled, membranous sacs (2)
outermost layer of placenta (chorion) attaches to uterine lining
-fetal and maternal blood vessels are in close proximity to each other in this area
-site of exchange of blood and nutrients and waste
73
amnion
(placenta)
membranous layer immediately surrounding the fetus
-forms the amniotic sac
-fetus floats in amniotic fluid inside the amniotic sac
74
allantois
(placenta)
layer surrounding amniotic sac
-forms allantoic sac which accumulates wastes
-outside of allantoic sac is covered by the chorion
75
chorion
(placenta)
attaches to lining of uterus
linked to fetus by the umbilical cord
76
diffuse placental attachement
ex. horse or pig
77
cotyledonary placental attachement
ex. ruminant
78
zonary placental attachement
ex. dog, cat
79
discoid placental attachement
ex. primates, rodents, rabbits
80
eustocia
normal parturition
81
dystocia
```
prolonged or difficult parturition
due to:
excessive fetal size
abnormal presentation
multiple births
```
82
stages of parturition
stage I: initiation of uterine contractions and cirvical dilation
Stage II: expulsion of fetus
Stage III: expulsion of placenta
83
parturition initiated by the fetus
fetal maturation and stress
-responds w/ cortisol from fetal adrenal gland
fetal cortisol causes
-removal of maternal "progesterone block" on uterine contractions
-stimulation of cervical secretions
-effects on fetus: final lung maturation
84
stage I parturition
removal of progesterone block inc. uterine contractions
uterine contractions --> pressure on cervix --> release of oxytocin -> uterine contractions
usually 2 to 6 hours
dilation of cervix "fully effaced" - becomes flush w/ vagina
relaxation of pelvic ligaments
lubrication of birth canal
85
stage II parturition
expulsion of fetus
usually less than 1 hour
rupture of chorioallantoic and amniotic sacs
-lubrication
uterine labor wave contractions superimposed w/ abdominal muscle contractions
propulsion of fetus into vagina
86
neonate first breath
rupture of umbilicus and or detachment of placenta from uterus
hypoxia
massive stimulation of nervous system
expansion of lungs
87
stage III parturition
expulsion of fetal membranes
-litter bearing species have interspersed stage II and III
constriction of blood vessels @ maternal fetal union
oxytocin for continued uterine contractions and continued vasoconstriction
timing:
mare: 1-3 hrs, cow: 6-12hrs, sow 1-4hrs
88
reproductive technologies
artificial insemination
| estrus synchronization
89
artificial insemination
approx 80% of dairy cows
bull ejaculate contains about 5mL w/ about 1 billion sperm per mL = 5 billion sperm/ ejaculate
typical AI does is 10 million sperm 500 doses
90
estrus synchronization
homronal injection protocol to control female cycle
often used in dairy management in conjunction w/ AI
simplest form is to give injections of PGF2 during diestrus
-causes regression of CL - allows rapid growth of follicles
-estrus and ovulation about 3 days later
no effect if CL not present (ie not in diestrus)
therefore give 2 injections about 14 days apart
91
timed artificial insemination
give GnRH to cause LH surge
-forces follicle to ovulate
not heat detection dependent
-pre arranged breeding schedule
92
embryo transfer
donor cow - given FSH to super ovulate and GnRH to time breeding
recipient cow - synched to donor cow's cycle
blastocyst collected on day 7 by flushing donor uterus
transfer 1 egg to each recipient that is also on day 7 of cycle
day 7 blastocyst needs day 7 uterus
