Chapter 14 - Exam 4 Flashcards
Mammals with a placenta
Eutherian mammals
Ensures that the developing conceptus will be provided with adequate nutrition and protection during its development
Intrauterine development
Animals which lay eggs
Can’t completely protect eggs from environmental or predatory danger
Oviparous
Final steps of reproduction are
Formation of a placenta
Acquisition of endocrine function of the placenta
Parturition
Transient organ of metabolic interchange between the conceptus and dam
A transient endocrine organ
Produces a variety of hormones
Placenta
The placenta is composed of a ________ component and a ________ component
Fetal
Maternal
Giving birth to young
Final step in reproductive process
Parturition
Parturition is initiated by the
Fetus
Parturition involves complex cascade of endocrine events that promote….
Myometrial contractions
Dilation of cervix
Expulsion of fetus and extra embryonic membranes
Functional unit of the fetal placenta
Chorionic villus
Small, finger-like projections that appear on the surface of the
Chorion
Placentas are classified by distribution of _________ ______ on surface of chorion
Chorionic villi
4 types of placenta:
Diffuse
Cotyledonary
Zonary
Discoid
Type of placenta: uniform distribution and of chorionic villi which cover the surface of the chorion
Sow and mare
Diffuse
Animal placenta: velvet-like surface with many closely spaced chorionic villi
Sow
Animal placenta: many specialized “microzones” of chorionic villi
Mare
Specialized “microzones” of chorionic villi
Microcotyledons
Unique transitory structures of chorionic villi in the mare
Produce eCG
Endometrial cups
Type of placenta: large number of discrete button-like structures (cotyledons)
Unit of placenta of trophoblastic origin consisting of abundant blood vessels and connective tissue
Cotledonary
Type of placenta found in ruminants
Cotyledonary
Type of placenta found in mares and sows
Diffuse
How many Cotyledons does an ewe have
90-100
How many cotyledons does a cow have
70-120
Point of interface between placenta and uterus
Placentome
Placentome consists of
Feral cotyledon
Maternal caruncle
Type of placenta: band like zone in center of placental unit
Zonary
Type of placenta found in dogs and cats
Zonary
Type of zone: highly pigmented ring at either end of central zone
Consists of small hematomas
Unknown function
2nd zone
Type of zone: transparent on distal ends of chorion
Poor vascularity
3rd zone
Type of placenta: either 1 or 2 disc-like structures on the chorion
Discoid
Type of placenta found in humans and rodents
Discoid
4 types of placenta based on number of placental layers
Epitheliochorial
Endotheliochorial
Hemochorial
Hemoendothelial
Least intimate among placental types
Both endometrial epithelium and epithelium of chorionic villi remain intact
7 placental layers
Epitheliochorial
Animals with 7 placental layers (epitheliochorial)
Sow
Mare
Ruminants (cow and ewe)
Subsection of Epitheliochorial
Syndesmochorial
A unique cell type found in the ruminant placenta
Quite large with 2 nuclei
Binucleate giant cells (BNGC)
Binucleate giant cells originate from
Trophoblast cells
Binucleate giant cells secrete
Placental lactogen
Pregnancy specific protein B
Protein unique to ruminants
Pregnancy specific protein B
Complete erosion of endometrial epithelium and surrounding interstitium
Maternal capillaries are directly exposed to epithelial cells of chorion
5 layers
Endotheliochorial
What animals have 5 placental layers (endotheliochorial)
Dogs
Cats
_________ is more intimate than epitheliochorial because there is no ________ _______
Endotheliochorial
Endometrial epithelium
Chorionic epithelium is in direct apposition to maternal pools of blood
Nutrients and gases are exchanged directly from maternal blood and must move through only 3 layers
3 layers
Hemochorial
What animals have 3 placental layers (hemochorial)
Primates
Mice
Most intimate type of placenta
Barriers to waste nutrients and gaseous transfer are almost non-existent
No direct exchange of blood components between fetal and maternal side
1 layer
Hemoendothelial
Animals with 1 placenta layer (hemoendothelial)
Rabbit
Rat
Guinea pig
Placenta regulates exchange between ____ and _____
Fetus
Dam
Placenta mechanism:
Gases and water pass from low to high concentrations
Active transport pumps for sodium, potassium, and calcium
Simple diffusion
Placenta mechanisms:
Simple diffusion
Facilitated diffusion
Active transport
Placenta mechanism: glucose and other metabolically imported materials are transported using carrier molecules
Facilitated diffusion
Major source of energy for the fetus
Glucose
Glucose is most derived from
Maternal circulation
Results from metabolism of body fat, which generates ketones for energy when glucose is limited
Ketosis
Ketosis after parturition is common in _____ ____ where metabolic demands are high due to _____ _________
Dairy cows
Milk production
Immunoglobulins can be transported in __________ and ________ placentas
Endotheliochorial
Hemochorial
Fetus synthesizes it’s own proteins from ______ ______ that are contributed from the dam
Amino acids
Can or can’t cross the placenta: immunoglobulins
Can
Can or can’t cross the placenta: maternal proteins
Can’t
Can or can’t cross the placenta: large peptide hormones
(Thyroid stimulating hormone, adrenal cortical stimulating hormone, growth hormone, insulin, glucagon)
Can’t
Can or can’t cross the placenta: small molecular weight hormones
(Steroids and thyroid hormones)
Can
Can or can’t cross the placenta: lipids
Can’t
Can or can’t cross the placenta: water soluble vitamins
Can
Can or can’t cross the placenta: fat soluble vitamins
Can’t
Can or can’t cross the placenta: toxic and potentially pathogenic compounds
(Ethyl alcohol, lead, phosphorous, mercury)
Can
Can or can’t cross the placenta: drugs and pharmaceuticals
(LSD and amphetamines)
Can
Can or can’t cross the placenta: microorganisms
Can
Can or can’t cross the placenta: viruses
(Measles and HIV)
Can
Placenta produces hormones that can: stimulate _______ ________
Maintain ________
Influence _____ _______
Stimulate ________ __________
Assist in _________
Ovarian function
Pregnancy
Fetal growth
Mammary function
Parturition
1st gonadotropin of placental origin is
eCG
eCG acts as a ______ and provides stimulus for maintenance of ______ ___
Leutropin
Primary CL
As eCG increases, the pregnant mare will often
Ovulate
eCG promotes luteunization of ______ _______ which don’t ovulate
Antral follicles
eCG has _____ -like actions in other species
FSH
2nd gonadotropin of placental origin is
hCG
hCG is produced by
Trophoblast cells
hCG is the basis for
Pregnancy tests
hCG can be detected in ____ or _____ of pregnant women
Blood
Urine
hCG role: to provide ______ stimulus for transition of _______ CL to CL or ________
Luteotropic
Ovulatory
Pregnancy
Luteal cell receptors bind hCG resulting in sustained
Luteal progesterone production
hCG can be used to induce ______ in other species
Ovulation
What also secretes progesterone and estrogen
Placenta
Inhibits myometrial contractions (induces quiescence) and provides stimulus for elevated secretion by the endometrial glands
Progesterone
A peak in most species signals the early preparturient period
Estrogen
Placental lactose has been found in
Rats
Nice
Sheep
Cows
Humans
Placenta has _______ and _______ properties
Somatotropic
Lactogenic
Promotes growth of fetus
Somatotropic
Stimulates the mammary gland
Lacrogenic
Promotes cervical softening
Relaxin
Relaxin is found in
Humans
Mares
Cats
Pigs
Rabbits
Monkeys
Fetus triggers the onset of partition by initiating a cascade complex ______/_______ events
Endocrine/biochemical
3 stages of parturition
Initiating by myometrial contractions
Expulsion of fetus
Expulsion of fetal membranes
Stage 1 of parturition is initiated by the
Fetus
Peptide hormone secreted in response to stress
ACTH
ACTH stimulates fetal adrenal cortex to produce
Corticoids
Elevation of corricoids causes removal of the myometrial _____ _____ enabling contractions to begin and causes elevation of _______ ____ ______, particularly by the cervix
Progesterone block
Reproductive tract secretions
Feral cortisol promotes synthesis of 3 enzymes that convert _________ to ______
Progesterone to estradiol
Fetal corticoids causes ______ to synthesize
Placenta
What helps abolish the progesterone block
PGF2alpha
Stage 2 of parturition requires strong ______ and _______ muscle contractions
Myometrial
Abdominal
As pressure increases in uterus, fetus rotates so front feet and head are positioned to _______ of dam
Posterior
If rotation doesn’t occur, ______ may occur
Dystocia
What further facilitates Myometrial contractions
Oxytocin
Pressure ________, oxytocin _________, ________ _______ reach peak = fetus enters ______ ______
Increases
Increases
Myometrial contractions
Cervical canal
Relaxin is stimulated by
PGF2ALPHA
Causes softening of connective tissue in cervix and promote elasticity of pelvic ligaments
Relaxin
What initiated secretory activity of the entire reproductive tract
Estradiol
As estradiol increases, cervix and vagina produce
Mucus
Washed out cervical seal of pregnancy and lubricates cervical canal and vagina
Mucus
Reduces friction and enables fetus to exit reproductive tract with relative ease
Mucus
Leads to rupture of placental membranes releasing amnionic and allantoic fluid
Pressure
Serves to lubricator the birth canal
Amnionic and allantoic fluid
As fetus enters birth canal, becomes
Hypoxic
Deprived of adequate levels of oxygen
Hypoxic
Stage 3 of parturition involved expulsion of the
Fetal membranes
Causes of Dystocia
Size of fetus
Improper fetal rotation
Multiple births in monotocous species
What term was derived from the false notion that Julius Caesar was born by removing him from his mother through an incision on the abdominal and uterine wall
Caesarean
In what species does the female incubate the eggs in her mouth and in some species the male does the same
Teleost fishes
In what species are males responsible for gestation
Pipe fishes
Sea horses
What offers a special environment for developing offspring and under the control of prolactin
Brood pouch
Lampreys use ____ to weigh down eggs and prevents them from floating downstream
Sand
Infant kangaroos in their mother’s pouches nurse from ___ nipples, and two babies of different ages commonly nurse at the same time
Two
Kangaroos produce two kinds of milk:
The younger kangaroo gets _____ _____ ___
The older kangaroo gets ____ ____
Fully rich milk
Skim milk
What is the most prolific mammal in existence
Multimammate rat
The mutimammate rate has ___ teats, the most of any female mammal
24
What species act as housewives to other females
Egyptian spiny mouse
The female african elephant has a gestation period of ___ years
1.8
An African elephant calf weighs about ___ pounds at birth and nurses for ___ years
300
3
During the 19th century, adultery was so feared that the ______ ____ was invented
Chastity belt
During the Middle Ages, _________ was considered to be an honest and essential profession
Prostitution
__________ was considered as a means to prevent adultery, homosexual tendencies and masturbation
Prostitution
The Mayans believed in a
Maize god
The Mayans believed that _____ was symbolic of both the male and female
Corn
Convex species
Cow
Giraffe
Concave species
Sheep
Goat