Final Flashcards
(109 cards)
1
Q
What is placentation?
A
The formation of the placenta (transient organ of pregnancy)
2
Q
What are the functions of pregnancy?
A
- Protection
- Fetal/maternal exchange
- Endocrine organ
3
Q
How does the placenta protect from?
A
- Physical such as shock, trauma, and disturbance
- Biological such as maternal immune system and toxins
4
Q
What is the fetal/maternal exchange?
A
- Exchanges nutrients, gases, waste, and hormones
- Through mechanisms such as diffusion, facilitated diffusion, and active transport
5
Q
What hormones does the placenta produce (endocrine organ)?
A
Progesterone, estradiol, placental lactogen, glycoproteins, eCG, and hCG
6
Q
What are the components of placentation?
A
- Embryonic/fetal - extraembryonic membranes
- Maternal - endometrium
7
Q
When do the extraembryonic membranes form?
A
Before implantation in domestic species
8
Q
When does the maternal endometrium form?
A
By differentiation of endometrial cells during implantation
9
Q
Extra embryonic membrane formation in ruminants and pigs?
A
The chorion and dorsal portion of the amniotic wall remain fused in the mesamnion
10
Q
Extra embryonic membrane formation in horses, dogs, and cats?
A
- Allantois surrounds the amnion completely
- Umbilical torsion in equine pregnancies
11
Q
What is implantation?
A
Penetration of the conceptus into the endometrium
12
Q
Implantation in domestic species?
A
- The attachment of the conceptus to the endometrium (conceptus remains in uterine lumen)
- Requires apposition and attachment of conceptus to endometrium
- Different presentation across species
13
Q
Why is implantation important?
A
Allows completion of placentation
14
Q
Conceptus nutrition methods during implantation?
A
- Pre and peri: histotroph
- Post with functional placenta: haemotroph
15
Q
What is histotroph?
A
Becomes limitation with the development of the conceptus
16
Q
What is haemotroph?
A
Allows exchange of nutrients, hormones, gases, and waste between fetal and maternal blood circulation
17
Q
What are the attachment and implantation phases?
A
- Hatching
- Apposition
- Adhesion
- Invasion
18
Q
Implantation in primates and rodents?
A
- Shortly after blastocyst hatches
- True implantation & decidualization of endometrium
- Conceptus penetrates epithelium and becomes completely embedded
19
Q
What are the placenta types - chorionic villi?
A
Diffuse, discoid, cotyledonary, zonary
20
Q
What are the placenta types - layers?
A
Epitheliochorial, synepitheliochorial, endotheliochorial, hemochorial
21
Q
What is a diffuse placenta?
A
Chorionic villi evenly distributed
Ex. sows and mares
22
Q
What is a cotyledonary placenta?
A
Chorionic villi are cotyledons (button-like)
Ex. ruminants
23
Q
What is a zonary placenta?
A
Band around fetus with chorionic villi
Ex. dogs and cats
24
Q
What is a discoid placenta?
A
Disc structure
Ex. humans and rats
25
What are the fetal layers?
Always present
1. Endothelium of blood vessels
2. Connective tissue
3. Allantochorion
26
What is an epitheliochorial placenta?
- 6 layers
## Footnote
Ex. mare and sow
27
What is a synepitheliochorial placenta?
- 5-6 layers
- Sometimes no endometrial epithelium
## Footnote
Ex. cow, ewe, doe
28
What is an endotheliochorial placenta?
- 4-5 layers
- No endometrial epithelium
- Sometimes no connective tissue
## Footnote
Ex. bitch and queen
29
What is a hemochorial placenta?
- 3 layers
- No maternal layers
## Footnote
Ex. woman and mouse
30
What is a sow placenta?
- Diffuse epitheliochorial
- Chorionic villi
31
What is a mare placenta?
- Diffuse epitheliochorial
- Microcotyledons
- Endometrial cups
32
What is a ruminant placenta?
- Cotyledonary synepitheliochorial
- Placenta = cotyledon (f) + caruncle (m)
- Convex: cow
- Concave: sheep and goat
33
What are binucleated giant cells?
- differentiate by endoreduplication of genetic material without cytokinesis
- migrate to maternal side and fuse with endometrial epithelial cells forming trinuclear cells
- trinuclear fuse to syncytial plates
34
What do binucleated giant cells secrete?
PAGs, placental lactogen, and progesterone.
35
PAG concentration during the peri-implantation period?
the more PAGs the greater the chance of pregnancy survival
36
______ can be used for pregnancy diagnosis in ruminants
PAGs.
37
What do endometrial cups secrete?
eCG in early pregnancy.
38
eCG
luteotropic activity and induces formation of accessory CL
39
What is hCG?
It has luteotropic activity in primates and is used in commercial pregnancy tests for women.
40
placental progesterone secretion during pregnancy
- no longer relies on CL for progesterone
- woman: 2 months
- cow: 6-8 months
- mare: 3 months
- ewe: 2 months
41
Which species only secrete progesterone from CL?
queen, bitch and sow
- no placental progesterone secretion
42
What are the activities of placental lactogen?
Somatotropic (fetal growth) and lactogenic (milk) is fairly even throughout most species except for ewe, woman (high), and rat.
43
partuition
- triggered by fetus
- fetal stress causes release of fetal cortisiol
- progesterone converts to estradiol
- PGF2a secreted from placenta
44
What is the Ferguson reflex?
Estradiol and PGF2a cause increased myometrial contractions which increases oxytocin until strong enough to push the fetus out.
45
What are the 3 stages of partuition?
1. Myometrial contractions and cervical dilation
2. Fetal expulsion
3. Fetal membrane expulsion.
46
What is dystocia?
Difficulty at birth that might result in serious complications for both fetus and dam.
47
What factors affect dystocia?
Fetal size, twins, multiple fetuses in the birth canal, maturity of female, uterine torsion, nutrient deficiencies, position/presentation of fetus.
48
posterior fetal positioning
- often no complications
- if long labour assist
- calf death possible from rupture of navel cord and suffication
49
What is breech fetal positioning?
- posterior with rear legs under calfs body
- can be corrected by grabbing calves feet and repositioning
50
What is dorso-vertical fetal positioning?
- posterior with fetus upside down
- can be caused by uterus twisting or calf rotation
- c-section
51
What is ventro-vertical fetal positioning?
- anterior presentation with rear legs beneath body
- can lead to fetal death
52
What is puerperium?
Postpartum period when reproductive tract returns to non-pregnant state.
53
How long does puerperium occur?
Starts immediately after birth (parturition) and lasts until reproductive function is established.
54
What is lactation?
The synthesis, secretion and removal of milk from the mammary glands for the nourishment and survival of the newborn.
55
When does lactation occur?
Immediately after birth (parturition) and lasts until weaning of offspring.
56
What are the main events of puerperium?
1. Expulsion of fetal membranes and lochia
2. Uterine involution and endometrial repair
3. Elimination of microbial contamination of reproductive tract
4. Resumption of regular ovarian function and estrus cyclicity.
57
What happens if fetal membranes are retained?
Increased susceptibility to uterine infections and development of metritis.
58
How is the fetal membrane expelled?
1. Chorionic villi mature and periparturient changes lead collagenases to breakdown interface
2. Myometrium contractions and vasoconstriction to initiate tissue death (less O2)
3. Maternal immune system recognizes placenta as foreign and produces cytokines
4. Neutrophils migrate to maternal interface
5. Detachment of chorionic villi
6. Expulsion of fetal membranes.
59
What factors increase collagenase activity?
- Reduced serotonin from mature fetal MAO
- Maternal immune system releases leukocytes and cytokines
- Relaxin serotonin from increased estrogen.
60
Is there a relation between impaired neutrophil function and retained placenta?
True.
61
uterine involution in a postpartum cow?
Uterus returns back to normal size.
62
What is lochia?
Amniotic and allantoic fluid, blood, and placenta cellular debris.
63
expulsion of lochia?
- Volume decreases as days postpartum increases
- If too much left inside, bacteria growth can lead to infection.
64
What is the endometrial damage from uterine disease?
If enough bacteria, it can attack uterine wall and cause damage.
65
negative feedback in hypothalamus from _____ drop and ______ spike (during birth) causes reduction in GnRH and HPG axis needs to _____ because the _____ is higher than estrus
progesterone; estradiol; reset; magnitude
66
How long does it take to see the first follicular wave after parturition?
4 days.
67
What does resumption of estrous cyclicity depend on?
Varies among individuals and depends on energy status and suckling activity.
68
How does resumption of estrous cyclicity work?
- GnRH pulse frequency increases with positive feedback of estradiol in surge center leading to surge in GnRH
- LH follows GnRH and surges
- Preovulatory LH surge causes ovulation.
69
What is metabolism's role in resumption of estrous cyclicity?
Reduced glucose, insulin, IGF1 has a positive effect and increases follicle responsiveness to LH; increased BHBA, NEFA has negative.
70
What is suckling's role in resumption of estrous cyclicity?
Causes release of opioids in the brain that negatively affect secretion of GnRH.
71
What is nutritional anestrus in dairy cows?
- As body condition score anovular cows decrease
- Anovulation determined based on circulating progesterone
- Low-low cows (low progesterone) = anovular.
72
low body condition score
- Lower insulin and IGF1 and higher NEFA and BHBA
- Reduced steroidogenesis of dominant follicle
- Impaired responsiveness of dominant follicle to LH
- Extended anovulation.
73
high body condition score
- Higher insulin and IGF1
- Lower NEFA and BHBA
- Enhanced steroidogenesis of dominant follicle
- Improved responsiveness of dominant follicle to LH
- Estrous resumed faster.
74
When do most farms start breeding again (cattle)?
60 days.
75
lactation anestrous in beef cows
Calf suckling impairs GnRH production and LH remains low during anestrous period.
76
anestrous in ewes and does
lambing and kidding season is usually out of breeding season, but same as beef
77
_____ in good condition dont have lactational anestrous
Mares.
78
foal heat?
estrus event occuring 7-12 days postpartum
pregnancy per breeding is 10-20% lower
79
weak or no lactational anestrous in ______
Queens.
80
What is anestrous in bitches?
Prolonged physiological.
81
ruminants undergo ________ of the brain with progesterone so brain can respond to estradiol similar to _______
repriming; puberty
82
Why is lactation considered a reproductive strategy in mammals?
Considered a final investment in the survival of the offspring.
83
mammary gland function?
Secretes milk for the nourishment and survival of the newborn.
84
What is colostrum?
The first milk produced from the mother and supplies nutrition and immune protection to the newborn.
85
What is the basic structure of the mammary gland?
Highly evolved and complex epidermal gland with a branched tubule-alveolar structure and an apocrine mode of secretion.
86
What is the external anatomy of the mammary gland?
Differs between species but similar milk secretion mechanisms.
87
mammary gland internal anatomy
- Very similar throughout species
- Broken down into parenchyma and stroma.
88
mammary gland parenchyma
- Secretory (glandular) portions comprised of alveoli, ducts, epithelial cells and cisterns
- Derived from ectoderm and embedded in stroma.
89
mammary gland stroma
- Derived from mesoderm
- Cellular portion: adipose tissue, blood vessels, nerves, myoepithelial cells, fibroblasts, and immune cells
- Acellular portion: supportive connective tissue, extracellular matrix and collagen.
90
alveolus - parenchyma tissue
secretory basic unit of the gland, lined by secretory epithelial cells
91
ducts - parenchyma tissue
Drainage of milk from alveoli.
92
streak canal and sphincter muscle - parenchyma tissue
Keeps milk inside and bacteria outside of udder.
93
What are the secretory pathways in the mammary gland?
1. Paracellular - plasma components and leukocytes
2. Exocytosis - proteins, lactose, calcium etc.
3. Transcytosis - from blood stream (immunoglobulins)
4. Lipid - milk fat MFMG
5. Apical transport - ions, water, glucose.
94
mammary epithelium
- Lined by epithelial cells that synthesize and secrete milk
- Has an alveolus surrounded by capillary network, myoepithelial cells, basement membrane, and interstice
- Terminal ducts provide a way out for milk produced.
95
mammary epithelium alvelous
Small, bulb-shaped structure with hollow center/lumen that collects milk components.
96
capillary network surrounding alveolus
Supplies milk precursors and delivers hormones.
97
nyoepithelial surrounding alveolus
Induce milk ejection by contraction when stimulated by oxytocin.
98
terminal duct of mammary epitlium structure
Lined by 2 layers of epithelium and myoepithelial cells arranged longitudinally.
99
What controls the neural regulation of milk let down?
Controlled by the nervous system.
100
What is the relationship between the parasympathetic and sympathetic systems in milk let down?
Parasympathetic system relates to normal activity; sympathetic system inhibits milk let down.
101
What is the somatic nervous system's response to external stimuli?
- Stimulus: touch (calf suckling, udder wipe), sounds, visual
- Response: oxytocin release, muscle contraction, milk ejection.
102
What is colostrum?
First milk after calving and contains high concentration of immunoglobulins.
103
Why is colostrum important?
Newborns are immunocompromised at birth; without it, calves have a greater potential of death and reduced performance.
104
What is mammogenesis?
- The process of structural gland development
- Prenatal and postnatal, most development during late pregnancy.
105
What is lactogenesis?
- The process of milk synthesis and secretion
- Few weeks prior to parturition and after parturition.
106
What is milk secretion?
The synthesis/secretion by epithelial cells to alveolar lumen.
107
What is milk removal?
The passive removal from the cisterns and the ejection of milk from the alveolar lumen.
108
What is the combined process of milk secretion and removal?
Lactation.
109
What maintains or enhances lactation once established?
Galactopoiesis.
