Term
| What does parturition require? |
|
Definition
- dilation of the cervical canal to accomodate passge of the fetus from the uterus from the vagina and to the outside
- contraction of uterine myometrium that are suffieciently strong to expel the fetus
- expulsion of the placenta
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|
|
Term
| What is the function of PGF2alpha in parturition? |
|
Definition
- it initiates uterine contraction and regression of the CL.
- stimulates synthesis of relaxin
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|
|
Term
| What is the function of relaxin from the CL and the placenta during parturition? |
|
Definition
| it softens the cervix as a result of the dissociation of connective tissue |
|
|
Term
| What is the function of oxytocin from the hypothalamus in parturition? |
|
Definition
| it initiates true labor; rhythmic directional contractions |
|
|
Term
| What happens during stage one of parturition? |
|
Definition
- uterine contractions
- cerzix opens as the calf pushes against it
|
|
|
Term
| What happens during stage 2 of parturition? |
|
Definition
| the calf moves through the open cervix, hips, and vaginal canal |
|
|
Term
|
Definition
|
|
Term
| What happens if the placenta is retained? |
|
Definition
- immature placentation (non-infectious abortion, premature parturition)
- periparturient immuno-supression (leukocytes and cotyledon)
- edema of chorionic villi (C-section, torsion)
- placentitis, cotyledonitis (infectious abortions)
- uterine atony (milk fever)
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|
|
Term
|
Definition
| an abnormal or difficult labor |
|
|
Term
| What are some possible causes of dystocia? |
|
Definition
- incoordinate uterine activity
- abnormal fetal lie or position
- absolute or relative cephalopelvic disproportion
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|
|
Term
| What is commonly used to treat incoordinate uterine activity? |
|
Definition
|
|
Term
| At fertilization, there is a huge spike in the secretion of the human placental hormone ________________. |
|
Definition
| human Chorionic Gonadotropin |
|
|
Term
| At fertilization, what other two hormones gradually start to increase in secretion? |
|
Definition
| estrogen and progesterone |
|
|
Term
| What human placental hormone gradually starts to decrease throughout pregnancy? Explain. |
|
Definition
| human chorionic gonadotropin starts to gradually decrease but not until after the spike at fertilization |
|
|
Term
| Parturition is accomplished through a __________ cycle. |
|
Definition
|
|
Term
| What are the teats of a cow like? |
|
Definition
|
|
Term
| What are the teats of a ewe like? |
|
Definition
| 2 teats, one opening, sparse hair |
|
|
Term
| What are the teats of a mare like? |
|
Definition
| 2 teats with 2 openings; short and laterally flattened |
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|
Term
| What are the teats of a sow like? |
|
Definition
| 12 to 14 teats, small, long, cylindrical; 2 inguinal pairs, 3 abdominal pairs, 2 thoracic pairs; 2-3 openings |
|
|
Term
| When does development of mammary glands start and finish? |
|
Definition
|
|
Term
| Mammary glands are modified _____________. |
|
Definition
|
|
Term
| How doe mammary glands develop? |
|
Definition
| they develop from a milk line which differentiates into mammary buds |
|
|
Term
| The development and functioning of mammary glands depends on _________. |
|
Definition
|
|
Term
| What other products influence the development of mammary glands? |
|
Definition
|
|
Term
| What hormone promotes mammary gland development? |
|
Definition
|
|
Term
| What hormone stimulates lobular alveoli formation? |
|
Definition
|
|
Term
| What hormones induce synthesis of the enzymes required for milk secretion? |
|
Definition
| prolactin and somatomammotropin |
|
|
Term
| How do high levels of estrogen and progesterone in late preganancy prevent lactation? |
|
Definition
| they block prolactin's stimulatory action on milk production |
|
|
Term
| ___________ promotes mammary gland development. |
|
Definition
|
|
Term
| What happens to the human placental hormones at parturition? |
|
Definition
|
|
Term
| What are the three main human placental hormones? |
|
Definition
| estrogen, progesterone, and human chorionic gonadotropin |
|
|
Term
| Where is corticotrpin releasing hormone secreted from? |
|
Definition
|
|
Term
| What does corticotropin releasing hormone lead to the secretion of? |
|
Definition
| ACTH (adrenocorticotropin hormone) |
|
|
Term
| Corticotropin releasing hormone causes the secretion of ACTH. What does this ACTH do? |
|
Definition
| it causes the production of cortisol and DHEA |
|
|
Term
| What is the function of the cortisol that is released as a result of ACTH? |
|
Definition
| it prepares the lung for breathing by causing the release of surfectant |
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|
Term
| What is the function of the DHEA that is released as a result of the secretion of ACTH? What does this lead to? |
|
Definition
| it is converted to estrogen which leads to an increased level of estrogen |
|
|
Term
| Estrogen promotes the synthesis of _________. What does this prepare for? |
|
Definition
| connexins; this prepares for muscle contraction |
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|
Term
| Estrogen also increases ______ and increases the sensitivity of the uterus to ___________. |
|
Definition
|
|
Term
| How does estrogen increase the sensitivity of the uterus to oxytocin? |
|
Definition
| it increases the myometrial receptors for oxytocin |
|
|
Term
| Uterine contractions have a (negative/ positive) feedback for (more/less) __________. |
|
Definition
|
|
Term
| What are the three main functions that oxytocin are responsible for? |
|
Definition
- uterine contraction
- milk ejection during lactation
- maternal behavior
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|
|
Term
| What about oxytocin induces uterine contraction? |
|
Definition
| increasing oxytocin receptor concentration |
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|
Term
| Name the process that occurs prior to parturition starting with the release of CRH up to the release of cortisol and DHEA. |
|
Definition
- the placenta releases CRH which increases CRH level
- this goes into fetal circulation until it reaches the fetuses anterior pituitary
- this leads to a release of ACTH
- this increase in ACTH goes to the fetal adrenal cortex
- the adrenal cortex then releases cortisol and DHEA
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|
|
Term
| Explain what happens after cortisol level increases prior to parturition. |
|
Definition
- the increased cortisol level reaches the fetus's lungs causing the release of pulmonary surfectant
- this leads to lung maturation in preparation for breathing air
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|
|
Term
| Explain what happens as a result of DHEA secretion up to progesterone and estroegn secretion. |
|
Definition
- the increase in the level of DHEA goes to the placenta where it is converted to estrogen
- this leads to an increase in estrogen concentration and a decrease in progesterone secretion
|
|
|
Term
| What three things does the incerase in estrogen and a decrease in progesterone secretion lead to? |
|
Definition
- gap junctions between myometrial cells
- and increase in the number of oxytocin receptors in the myometrium
- an increase in prostaglandin production
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|
|
Term
| What does an increase in the number of gap junctions bewteen myometrial cells lead to? What does this lead to? |
|
Definition
| the uterus is then able to contract as a coordinated unit; the uterus is then responsive to low levels of oxytocin |
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|
Term
| What does in increase in the number of myometrial oxytocin receptors lead to? |
|
Definition
| it increases uterine responsiveness to low levels of oxytocin |
|
|
Term
| What does an increase in prostaglandin production lead to? |
|
Definition
|
|
Term
| What does an increase in reposniveness of the uterus to low levels of oxytocin lead to? |
|
Definition
| an increase in uterine contractions which causes the fetus to push against the cervix which causes more oxytocin to be released which leads to an increase in prostaglandins which causes more uterine contractions |
|
|
Term
| Explain the pathway for placentantal synthesis of progesterone. |
|
Definition
- cholesterol in the maternal blood enters the placenta
- cholesterol in the placenta causes the releases of progesterone from the placenta which enters the maternal blood
|
|
|
Term
| Explain the pathway for placental synthesis of estrogen. |
|
Definition
- cholesterol from the maternal blood enters the placenta which enters the fetal blood which enters the fetal adrenal cortex
- this leads to the synthesis of DHEA
- the DHEA enters the fetal blood which enters the placenta
- here the DHEA is converted to etrogen and this estrogen enters the maternal blood
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|
|
Term
| What does puberty estrogen stimulate the growth of with regards to mammary glands? |
|
Definition
|
|
Term
| Where does puberty estroegn come from? |
|
Definition
|
|
Term
| What does puberty progesterone stimulate the growth of with regards to mammary glands? |
|
Definition
|
|
Term
| What are estrogen and progesterone under the control of? |
|
Definition
| FSH and LH from the anterior pituitary |
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|
Term
| _________ stimulate lobular aveoli formation. |
|
Definition
|
|
Term
| _____________ and ____________ induce the synthesis of enzymes required for milk production. |
|
Definition
| prolactin, chorionic somatomammotropin |
|
|
Term
| How is lactation prevented? |
|
Definition
| the high level of estrogen and progesterone in the last half of pregnancy prevent lactation by blocking prolactin's stimulatory action on milk secretion |
|
|
Term
| What happens causes lactation to begin? |
|
Definition
| an abrupt decline in estrogen and progesterone |
|
|
Term
| Once lactation begins as a result in the ubrupt drop in estrogen and progesterone, what happens? |
|
Definition
- prolactin acts on aveolar epithelium to promote milk production
- oxytocin induces milk ejection from aveoli to lactiferous sinus
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|
|
Term
| What is the capsule surrounding the aveoli made of? |
|
Definition
|
|
Term
| What kind of cells produce milk? |
|
Definition
|
|
Term
| What kind of cells suround epithelial cells and what do they do? |
|
Definition
- myoepithelial cells suroound epithelial cells and they contract in response to oxytocin
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|
|
Term
| How many aveoli are there per lobule? |
|
Definition
|
|
Term
| What is the diameter of aveoli? |
|
Definition
|
|
Term
| What do aveoli drain into? |
|
Definition
| small intra lobular (excretory) ducts |
|
|
Term
| Aveoli contain both _________ cells and _________ cells. |
|
Definition
|
|
Term
| Intra-lobular ducts join to form large ______________ ducts which lead into a system of wide ____________ ducts. |
|
Definition
| interlobular, lactiferous |
|
|
Term
| What is the conformation of the lactiferous ducts of a cow like? |
|
Definition
| they have irregular luminal diameters and converge, in the cow, upon a single lactiferous sinus |
|
|
Term
| What are lactiferous sinuses sub-divided into? |
|
Definition
| a gland sinus and a teat sinus by a vascular annular ring |
|
|
Term
| How do the vascular annular rings connect to the exterior? |
|
Definition
| by the narrow teat canal (also called a streak canal) |
|
|
Term
| What is initiation of lactation called? |
|
Definition
|
|
Term
| What is the first stage of lactation? |
|
Definition
| when the aveoli gain the ability to secrete milk |
|
|
Term
| When does the first stage of lactation occur? How is it facilitated? |
|
Definition
| it occurs before parturition and is facilitated by enzymatic activity and differentiation of cellular organelles |
|
|
Term
| What is the second stage of lactation? |
|
Definition
|
|
Term
| What five things facilitate the second stage of lactation? |
|
Definition
- prolactin
- ACTH
- estrogen
- growth hormone (STH(somatotropin hormone))
- very low progesterone
|
|
|
Term
| What are prolactin levels like during gestation? |
|
Definition
| they are constant during gestation until it increases 24-48 hours before calving |
|
|
Term
|
Definition
| the main protein present in milk |
|
|
Term
| ___________ and __________ allow gene expression for casein synthesis. |
|
Definition
| prolactin, glucocorticoids |
|
|
Term
| Why must progesterone decrease in order for lactation to occur? |
|
Definition
| because it blocks the binding sites for prolactin |
|
|
Term
| What does prostaglandin do? |
|
Definition
| it regresses the CL and minimizes progesterone |
|
|
Term
| When does estrogen reach its maximum? What does the estrogen do at this point? |
|
Definition
| it reaches a maximum 30 days before parturition and stimulates the release of prolactin |
|
|
Term
| What does STH (growth homrone) do just before parturition? What is its function? |
|
Definition
| it increases and it is assumed to direct nutrients to the mammary gland |
|
|
Term
| What is the lactation curve of cows and sheep like? |
|
Definition
| it peaks just after parturition and gradually decreases |
|
|
Term
| What is the lactation curve of rabbits and rats like? |
|
Definition
| after parturition, it starts out low and then gradually increases and then it decreases again (like a parabola) |
|
|
Term
| What causes the decrease in milk production? |
|
Definition
| a decrease in milk secreting cells |
|
|
Term
| When lactation in a cow reach its peak? |
|
Definition
| 2-8 weeks after parturition |
|
|
Term
| What six hormones are involved in the maintenance of lactation? |
|
Definition
- prolactin
- STH (growth homone)
- thyroid hormone
- insulin and corticoids
- PTH (parathyroid hormone)
|
|
|
Term
| __________ and _____________ cause the aveoli to regress and thus reduce rate of lactation. |
|
Definition
|
|
Term
| What are the two main stimulai for lactation by a cow? |
|
Definition
- the sound of milking machine or the sight of a calf causes
|
|
|
Term
| After these stimuli, what happens and what is released? |
|
Definition
- the brain sends a signal to the posterior pirutiary which release oxytocin into the blood stream
|
|
|
Term
| What happens to the oxytocin that is released into the bloodstream? |
|
Definition
| the blood transports the oxytocin to the udder where it stimulates the contraction of the tiny muscles (the myoepithelial cells) surrounding the milk-filled aveoli |
|
|
Term
| When do contractions occur with reference to stimulation? |
|
Definition
| 20-60 seconds after the stimulation |
|
|
Term
| During milking, what does the squeezing action do? |
|
Definition
| it increases the intramammary pressure and forces the milk through the ducts to the gland and teat cistern |
|
|
Term
| How long does the action of oxtocin last? Why? |
|
Definition
| only six to eight minutes because its concentration in the blood decreases rapidly |
|
|
Term
| What is the second discharge of oxytocin like? |
|
Definition
| it is usually less effective than the first one |
|
|
Term
| Explain the pathway from suckling to milk ejection. |
|
Definition
- suckling stimulates mechanorecptors in the nipple
- this goes to the hypothalamus
- through a nervous pathway this reaches the posterior pituitary
- this causes oxytocin to be released which causes myoepithelial cells to contract
- this causes milk ejection
|
|
|
Term
| Explain the pathway from suckling to milk secretion. |
|
Definition
- suckling stimulates mechanoreceptors in the nipple
- this goes to the hypothalamus
- this causes a decrease in prolactin inhibiting hormone or an increase prolactin releasing hormone
- this goes to the anterior pituitary where prolactin is secreted
- this leads to milk secretion
|
|
|
Term
| Mamamry gland feeding is advanatageous to the __________ and the _________. |
|
Definition
|
|
Term
| What are the four main reasons that mamamary gland feeding is advantageous? |
|
Definition
- there is an abundance of immune cells (B and T lymphocytes), macrophages and neutrophils
- secretory IgA is present in great amounts in mammary gland milk
- lactoferrin decreases the availability of harmful microorganisms
- bifidus factor promotes nonpathogenic microorganisms in the infant's digestive tract
|
|
|
Term
| What animal has the highest percentage of fat, protein, and solids in its milk? |
|
Definition
|
|
Term
| What animal has the lowest percenatge of fat and protein in its milk? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| Colostrum is a source of __________. |
|
Definition
|
|
Term
| What are some of the non-immunoglobin components of colostrum? |
|
Definition
- enzymes and local immunity factors (intestinal protective factors)
- concentrated energy, proteins, vitamins, and minerals
- fluid, warmth
|
|
|
Term
| What are the two most importanat factors with regards to colostrum? |
|
Definition
| total immunoglobin mass and time after birth it is received |
|
|
Term
| What should the total mass of immunoglobun fed be? |
|
Definition
|
|
Term
| Colostrum must be fed prior to __________. |
|
Definition
|
|
Term
| When should the first feeding of colostrum be given? |
|
Definition
|
|
Term
| When should the second feeding of colostrum be given? |
|
Definition
|
|
Term
| Are immunoglobin, protein, fat, lactose, calcium, and phosphorus all higher in colostrum? |
|
Definition
|
|
Term
| Whjat happens to survival rate if an animal isn't fed enough colostrum? |
|
Definition
|
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