Review: Physiology Flashcards
Where does most of the repro system develop from embryologically?
Intermediate mesoderm
Thickenings of intermediate mesoderm:
Urogenital ridges
-Nephrogenic Ridge (lateral)
-Gonadal Ridge (medial)
Primitive kidney that is non-functional in mammals:
pronephros
intermediate kidney found in the thoracolumbar region:
Mesonephros
What gives rise to the cortex & medulla of the kidney?
Medulla- ureteric bud
Cortex- Metanephric blastema/metanephric cap
Dilation & branching of the ureteric bud forms:
Renal pelvis, major & minor calyces, collecting tubules
Stalk becomes ureter
Where does the metanephros form and where does it end up?
Formed in pelvic cavity, ascends cranially into abdomen
Embryologically, the cloaca is a portion of which structure:
Hindgut; caudal to the origin of the allantois
The urorectal septum divides which structure into which two structures:
Divides the cloaca into the ventral part (primitive urogenital sinus & membrane) and dorsal part (anorectal canal and anal membrane)
The urorectal septum is a wedge between which two structures?
Allantois & hindgut
What forms the perineal body:
Remnant of mesodermal tissue between the anus & urogenital sinus after the division of the cloaca
Three divisions of the cloaca and what they become:
Cranial vesicular part-> urinary bladder
Middle pelvic part-> pelvic urethra (males); entire urethra (females)
Caudal phallic part
What two structures does the urachus connect?
apex of the bladder and the umbilicus
What does the urachus become?
the median ligament of the bladder
The trigone of the bladder is derived from ______________ as it is formed by ______________________________________, while the rest of the bladder is derived from __________. The entire lining of the bladder is derived from ______________ and the smooth muscle of the bladder is derived from ______________________.
Mesoderm; absorbed mesonephric ducts in the dorsal wall of the bladder; endoderm; endoderm; splanchnic mesoderm
Common embryologic anomalies of the urinary system:
Renal agenesis
Hydronephrosis
Polycystic Kidneys
Congenital Nephromas
Pelvic Kidney
Horseshoe Kidney
Double Ureter
Ectopic Ureter
Anorectal atresia (urinary problem when fistulated)
The indifferent gonad will “default” to which sex if under the influence of no sex-determining factors?
Female
What is necessary for an indifferent gonad to develop into
Testis Determining Factor
Testosterone
Müllerian-Inhibiting Factor
What determines sex?
Presence of the SRY gene on the Y chromosome
Cow MROP:
Conceptus enters uterus ~day 5-6
Embryo elongates by day 13; must be in side with CL
MROP d15-18 (Bovine interferon t)
Mare MROP:
Conceptus enters uterus day 5-6
AV remains spherical and diameter increases rapidly
Inc. Embryo mobility/uterine contractions d11-16
MROP- Motility plays a large role; no hormonal signal identified
Fixed at day 16
Ewe MROP:
Conceptus enters uterus by day 5
MROP: d 12-14; ovine INFt
Sow MROP:
Conceptus enters uterus on day 3 as a 4-cell
MROP: d11-12
Estradiol from conceptus
Four embryos must be present to maintain pregnancy; 2 in each horn
Bitch/Queen MROP:
Conceptus enters the uterus
B: d9-11
Q: d4-5
MROP- unknown; similar hormonal environment to non-pregnancy
“Luteal Dependent” means:
The dam maintains ovarian production of progesterone for the entire pregnancy
“Luteal Independent” means:
only needs the CL of ovulation for the first part of pregnancy, then placental production takes over
Luteal dependent species:
Sow, Doe, Bitch, Queen
Luteal independent species:
Cow, Ewe, Mare
Which species has a placental source of gonadotropins during pregnancy?
Mares
eCG from the endometrial cups
Follicular phase
Regression of CL->Ovulation
*Growing dominant follicle
Estradiol
Proestrus + Estrus
Luteal phase:
Ovulation-> CL regression
CL present
Progesterone
Metestrus + Diestrus
Variation in location, number, and nipple openings of mammary glands correlate to:
Litter Size
Q
The mammary gland is an _____ gland that functions to:
Exocrine
Nourish the neonate
Explain how the mammary gland functions as a food source and as protection:
Food Source: Fat, protein, sugar (CHO), vitamins, minerals, water
Protection: Immunoglobulins (colostrum), first antibody protection
Components of bovine milk include:
Water
Fat
Solids (Protein, Lactose, Minerals)
Proteins included in milk include:
Casein and whey
Definition of milk solids:
Dried powder left after all the water is removed from liquid milk
Why does the amount of milk solids matter in real life?
Too much water and/or too few solids can lead to diarrhea and malnutrition
Milk replacer is typically what percent solids?
12-15%
The less total solids in a species’ milk, the _____ suckling occurs
MORE
Fat in bovine milk is made from:
Half from Acetate and Butyrate production in rumen
Half is pooled fatty acids from blood (body fat, diet, synthesized in liver)
____ have the most fat in milk, followed by ____ and finally _____ (least).
Sheep
Cows
Goats
Protein is formed in the mammary glands by:
Lactational epithelial cells
Milk protein is synthesized by:
Amino acids in blood
Glucose required (Propionate from rumen, breakdown of AA)
Casein is the ___ portion of the milk, and _____ is used to separate casein from whey
Curd
Acid treatment (Rennin)
Whey is the ______ portion of the milk and is mainly made of:
Liquid (by-product of cheese production)
Alpha-lactalbumin and beta-lactoglobulin
Lactose is a _________ composed of _____ and ______
Disaccharide; glucose/galactose
What is the rate limiting step for milk production in cattle? Why?
Lactose production
Based upon how much glucose is available from propionate
What are the inorganic components of milk?
High in: Ca, P, K, I, and vitamins
Low in: Na/Cl (less than blood)
Lower in: Fe, Se, & other micro minerals
Nonstructural carbohydrates include _________ and form _______ (VFA)
Concentrates (Sugar/Starch), Propionate
Structural carbohydrates include:
Lignin
Cellulose
Hemicellulose
Pectin
Cellulose produces _____ (VFAs), Hemicellulose produces ________, and Pectin produces _________.
Cellulose: Acetate, Butyrate
Hemicellulose: Acetate, propionate
Pectin: Acetate, propionate
VFAs provide how much of the energy requirement for the ruminant?
60-80%
Which VFA is most essential for milk production?
Propionate
More propionate = more lactose = more milk
Why don’t we feed mostly grains to increase milk production?
Leads to subacute rumen acidosis
What is colostrum?
The first secretion from the mammary glands after giving birth; rich in antibodies (but contains more than antibodies)
Which species get immunoglobulins from the placenta only?
Rabbits, guinea pigs, mice, primates
Which species get immunoglobulins in utero and from colostrum?
Dogs and cats
Which species get immunoglobulins from colostrum only?
Ruminants, horses, pigs
Embryogenesis/ Mammogenesis:
Development of the mammary gland tissue and growth
Lactogenesis:
Synthesis and initiation of milk secretion from the alveoli
Galactopoeisis:
Biosynthesis of milk
Lactation:
Full milk secretion and maintenance of lactation
Galactokinesis:
Ejection of milk
Involution:
Regression and atrophy of the mammary gland
Mammogenesis occurs from ______ to _______ and is known as ______________
Birth to puberty; allometric growth
During puberty, what parts of the mammary gland develop?
Ducts, alveoli, mammary epithelium (last trimester, “bagging up”)
Lactogenesis process:
Initiation of lactation
Stimulation at teat
Nerves carry message to pituitary
Release of prolactin and oxytocin
Bloodstream to udder
Milk letdown
Galactopoiesis process:
Alveolar secretory cells
Lactose: pumped into alveolus and fluids follow osmotic gradient
Proteins: excreted by golgi apparatus; casein forms micelles as it is insoluble in water (milky appearance)
Fat: droplets form in cell and extruded with a surface membrane
Galactokinesis process:
Reflex action: stimulation, auditory stimulus, conditioned reflex
Oxytocin (posterior pituitary)
Contraction of myoepithelial cells & relaxation of large alveolar ducts
Milk ejection
Milk ejection lasts:
5-20 min
Exogenous administration of oxytocin causes:
Will cause milk letdown in:
Heifers, cows with udder edema, removal of “residual” milk
Lactation length by species?
Swine: 21-28 days, 24 avg
Equine: 4-7 months
Canine: 6-10 weeks
Goats: 2-4 months, 8-10 months (Dairy)
Sheep: 2-5 months, 4-8 months (Dairy)
Beef: 6-8 months
Dairy: 10-12 months
What is the main way we start to “dry off” cattle?
Decrease feed intake, remove concentrates/forage
What is the benefit of dry cow treatment?
Reduces persistent mammary infections
Decreases infection during dry period
When do we start dry cow treatments?
45-60 days before calving
Factors that affect milk production?
Nutrition
Length of dry period
Frequency of milking
BCS at parturition
Describe Agalactia in mares?
Prolactin inhibited by dopamine
Fescue hay (Neotyphodium coenophialum)
Treatment/control of fescue toxicosis (agalactia) in mares?
Remove from fescue 30-60 days prepartum
Administer domperidone
What things cause involution of the mammary gland?
Decreased milking/nursing
Massive decline in metabolic activity of the mammary tissue
Degeneration of alveolar tissue
