Review: Physiology Flashcards by Madison Cogle

Where does most of the repro system develop from embryologically?

Intermediate mesoderm

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Thickenings of intermediate mesoderm:

Urogenital ridges
-Nephrogenic Ridge (lateral)
-Gonadal Ridge (medial)

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Primitive kidney that is non-functional in mammals:

pronephros

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intermediate kidney found in the thoracolumbar region:

Mesonephros

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What gives rise to the cortex & medulla of the kidney?

Medulla- ureteric bud
Cortex- Metanephric blastema/metanephric cap

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Dilation & branching of the ureteric bud forms:

Renal pelvis, major & minor calyces, collecting tubules
Stalk becomes ureter

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Where does the metanephros form and where does it end up?

Formed in pelvic cavity, ascends cranially into abdomen

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Embryologically, the cloaca is a portion of which structure:

Hindgut; caudal to the origin of the allantois

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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)

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The urorectal septum is a wedge between which two structures?

Allantois & hindgut

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What forms the perineal body:

Remnant of mesodermal tissue between the anus & urogenital sinus after the division of the cloaca

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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

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What two structures does the urachus connect?

apex of the bladder and the umbilicus

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What does the urachus become?

the median ligament of the bladder

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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

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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)

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The indifferent gonad will “default” to which sex if under the influence of no sex-determining factors?

Female

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What is necessary for an indifferent gonad to develop into

Testis Determining Factor
Testosterone
Müllerian-Inhibiting Factor

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What determines sex?

Presence of the SRY gene on the Y chromosome

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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)

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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

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Ewe MROP:

Conceptus enters uterus by day 5
MROP: d 12-14; ovine INFt

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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

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Bitch/Queen MROP:

Conceptus enters the uterus
B: d9-11
Q: d4-5
MROP- unknown; similar hormonal environment to non-pregnancy

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"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

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