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40 Cards in this Set
- Front
- Back
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RESPIRATORY SYSTEM
DEVELOPMENT 5 DEVELOPMENTS 2 KEY WORDS |
Respiratory Diverticulum
- forms as outpouching of ventral aspect of foregut Esophagotracheal Septum - separates respiratory system from GI system Elongation Branching - produces bronchi and bronchioles - branching can occur post natally Respiratory Movements - required in utero to aid development of musculature associated with respiration Precocial species have highest amount of in utero lung development |
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RESPIRATORY SYSTEM
ABNORMAL DEVELOPMENT NAME TWO |
Esophagotracheal Fistula
Hypoplasia |
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ESOPHAGOTRACHEAL FISTULA
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Incomplete speration of respiratory and digestive tract
Results from incomplete development of Esophagotracheal Septum Rare - can occur in any species - usually aquired vs congenital - mainly foreign body ingestion Presentation - aspiration pneumonia - bloating |
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RESPIRATORY TRACT HYPOPLASIA
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Can occur in any portion of respiratory tract
Tracheal - common in brachycephalic breeds Lung Hypoplasis - absence of lobe or portion of lobe - usually related to OTHER abnormalities that decrease size of thorax cavity ~~~ ie congenital diaphragmatic hernia |
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DIGESTIVE SYSTEM
DEVELOPMENT |
Develops as Tube
- suspended from dorsal and ventral mesentaries which are continuous - mesentary caudal to diaphragm - mediastinum cranial to diagphragm Ventral Mesentary - exists fully for short period - Ventral Mesogastrium ~~~~ important for development of lessor omentum - Caudal Mesentary ~~~~ contributes to median ligament of bladder - necrosis and apoptosis ablate majority of ventral mesentary Foregut - Pharynx - Esophagus - Stomach - Liver - Pancreas - Cranial Duodenum Midgut - remaining SI - cecum - ascending colon - portion of transverse colon Hindgut - remainder of transverse colon - descending colon - cloaca ~~~~ rectum ~~~~ anal canal - also contributes to urethra |
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SIMPLE STOMACH
DEVELOPMENT |
Starts as Tube
ASYMETRICAL growth DORSALLY - greater growth on dorsal aspect vs ventral aspect ~~~~ greates distention ~~~~ promotes curvature ROTATION - results from asymetrical growth - greater curvature of stomach becomes ventrally positioned |
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COMPLEX STOMACH
DEVELOPMENT |
ASYMETRICAL DORSAL GROWTH and ROTATION
- initially same as simple Expansion of Greater Curvature - forms Rumen ~~~~ Dorsal Sac ~~~~ Ventral Sac Expansion of Lessor Curvature - forms Omasum Pocket develops near Rumen - forms Reticulum Remainder of stomach - forms Abomasum - majority of stomach in neonate - nursing tf high protein diet does not require fermentation - abnormal development of muscular groove that facilitates movement of fluids from cardia to abomasum results in ~~~~ bloating ~~~~ maldigestion ~~~~ stunted growth |
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COMPLEX STOMACH
DEVELOPMENT MIGRATION |
Ventral Sac of Rumen initiates movement
- inverts caudal-dorsally - migrates to definitve left dorsal position Movement of Rumen forces Reticulum to move cranioventrally Omasum and Abomasum move to right |
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ROTATION OF GUT
AROUND CRANIAL MESENTERIC ARTERY |
Yolk Sac
- aids rotation - is cranial to majority of development - provides attachment along with Cranial Mesenteric Artery - tf as gut elongates it rotates around Cranial Mesenteric Artery ~~~~ viewed dorsally rotation is clockwise Development and Rotation take place outside of abdominal cavity - via Physiological Umbilical Hernia Development and Rotation is species dependent - Carnivores simple little twisting - Herbivores complex hindgut high amount of twisting |
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MECKEL'S DIVERTICULUM
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Remenant of Yolk Sac
Failure to Detach - results in abnormalities - diverticulum in Jejunum - Fistula between umblilicus and small intestine ~~~~ leakage of intestinal contents ~~~~ traps organs and intestines - sttachements ~~~~ trap organs and intestines |
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INTESTINAL ATRESIA
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ATRESIA
- occulsion of lumen Mechanisms - As GIT develops there is a large amount of proliferation ~~ internal proliferation can occlude lumen if relative rate exceeds elongation rate ~~ exacerbated by ~~~~ folds withing lumen ~~~~ lack of breakdown of cells withing lumen - Lack of blood Flow to specific portion of GIT ~~ low proliferation and elongation create oclusion - Lack of Regresion of Yolk Sac - Physical trauma ~~ ie Iatrogenic during palpation 1st trimester ~~~~ grapefruit size in cows Occurance - can be autosomal ressesive - Sheep most common - Cattle - Pigs - Dogs - Horses Presentation - Initally normal appetite - expansion of intestines and bloating - extreme pain - die within a few days |
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INTESTINAL ATRESIA
5 TYPES |
Oral end swells due to ingestion of amniotic fluid and accumulation of muconeum
Mucosal Web - thin membrane completely seperates proximal and distal ends Fibrous Cord - cord completely seperates proximal and distal ends Mesenteric Gap Defect - complete seperation of proximal and distal intestine Apple Core Type Deformity - long isolated segment of intestine coils upon itself Multiple Areas - several areas of mesenteric gap |
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ATRESIA ANI
NORMAL DEVELOPMENT |
Normal Development
Common Cloaca contains - exit from bladder - exit from hindgut - passage to alantois URORECTAL SEPTUM - develops in mammals - seperates urogenital and GI systems - Partitions cloaca CLOACAL MEMBRANE - prevents urinary of GI contents from entering Amnionic Fluid - eventually is divided by migration of Urorectal Septum to become - UROGENTITAL MEMBRANE - ANAL MEMBRANE |
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ATRESIA ANI
ABNORMAL DEVELOPMENT |
No Anus
Low Atresi Ani - lack of regression of Anal Membrane - usually easy to fix High Atresi Ani - lack of development of Anal Rectal Canal - may or may not involve lack of Anal Membrane Regression - usually have formed anus - involves rectal muscles - failure of cells to degenerate ~~ tf lumen ocluded - may or may not have anal sphincter - poor prognosis |
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FISTULAS
NAME 3 OF THE FAR END |
Urethral Rectal Fistula
Recto Vaginal Fistula Urethro Vaginal Fistula Result from - Failure of Urorectal Septum to migrate ~~ abnormalities of Cloaca ~~ interuption of migration ~~ tf temporary loss of blood supply - Premature Rupture of Cloacal Membrane ~~ tf no place for UroRectal Membrane to fuse Presentation - Urinary Infection - Passing urine through Rectum - Feces trapped or passed through Urethra - Urine Scalding |
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OVERO LETHAL WHITE SYNDROME
COURTESY OF JOE |
aka
- Congenital Ileocolic Agangliosis - Congenital Aganlionic Megacolin Overo - selected for by desire for specific white spotting pattern - pigmented dorsal midline - ventral white spotting laterally and ventral - HOMOZYGOUS DOMINANT IS LETHAL ~~ EDNRB gene Affected foals are completely white with blue irises - note not all foals of this phenotype are Homozygous for EDNRB Failure of NEURAL CREST CELL MIGRATION to Intestines - mainly colon - also ileum - results in absence of GANGLIA which are important for PARASTOLSIS - tf normal parstolsis in upper GI and absence in lower - tf build up of muconeum in lower GI enlarges colon - may also involve Atresia Ani or other Intesitinal (usually lower) Atresia Presentation - extreme pain - colic signs Occurence - mainly Paint Horses - other horse breeds - humans - rodents - similar syndrome in dogs Can be tested for in advance of breeding |
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URINARY SYSTEM
GENERAL DEVELOPMENT |
Intermediate Mesoderm
- Forms Urinary and Genital Systems - proliferates to form UROGENITAL RIDGE Urogenital Ridge - internally forms NEPHROGENIC CORD ~~ forms Kidney and Ureters - externally forms GONADORIDGE ~~ forms Gonads Note - kidneys function in fetus - not required because Dam extracts waste from allontioc fluid ~~ tf fetus can survive to term without kideys - kidneys ARE required for proper development of genetalia |
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KIDNEY DEVEOPMENT
PRONEPHROS |
Develops most crainialy
- 7 to 8 primative tubules - tubules fuse to form PRONEPHRIC DUCT Pronephric duct grows caudally to terminat in Cloaca Not functional in veterinary species - except sheep - degenerates shortly after development ~~ leaves pronephric duct behind ~~~~ becomes MESONEPHRIC DUCT |
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KIDNEY DEVEOPMENT
MESOONEPHROS |
Develops as Pronephros degenerates
Functional - 70 to 80 tubules - drains into MESONEPHRIC DUCT which drains into Cloaca Simialr Development to true Kidney - has Glomerulus and Loop in excretatory tubule - loop is NOT loop of Henle Degenerates - except for a few caudal tubules Mesonephric Duct - persists in males ~~ important for reproductive system - degenerates in females |
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KIDNEY DEVEOPMENT
METANEPHROS HOW MANY PARTS NAME THEM |
Forms Adult Kidney
- initially lobulated - subsequent fusion in applicable species URETERIC BUD - grows out of Mesonephric Bud - contributes to ~~ Ureter ~~ Renal Pelvis ~~ Collecting Ducts METANEPHROGENIC BLASTEMA - caudal region of Nephrogenic Cord - forms Nephrons Ureteric Bud imposes on Nephrogenic Cord - Nephrogenic cord is then induced to become Metanephrogenic Blastema - Metanephrogenic Blastema then induces Ureteric Bud to elongate and form ~~ Renal Pelvis ~~ Collecting Ducts - Renal Pelvis and Collecting Ducts induce Metanephrogenic Blastema to produce ~~ Nephrons |
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KIDNEY
MIGRATION |
Development of Metanephros occurs in close proximity to Cloaca and Rectum
Reproductive System development occurs at the same time Kidney migrates cranially at same time as Gonads migrate caudally - tf cross over of Mesonephric Duct and Ureters |
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BLADDER
DEVELOPMENT |
Bladder Develops as Expansion of Uracus
Urorectal Septum divides Bladder from GIT - forms UROGENITAL SINUS Entrance of Ureters into Bladder - occurs in TRIGONE REGION |
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URETERS
ECTOPIC |
Ureters DO NOT enter Trigone region of Bladder
- usually enter neck of bladder - also urethra - 75% unilateral ~~ may be asymptomatic - 25% bilateral ~~ always clinical signs Abnormal Development - usually result of abnormal development of Urogentital Sinus - also disruption of meso or meta nephric ducts ~~ tf ureter in urethra ~~ or Vas Defrens and Seminal Vesicles - also crossover of of Mesonephric Duct and Ureters - results in urine drainage into Vas Defrens and Seminal Vesicles Presentation - leaking - may have hypoplastic bladder - retrograde passage of urine ~~ tf urinary tract infections Occurance - Genetic Association - Most common in dogs - presentation at 3 - 6 months - symptoms vary depending on placement - Females 8x more likely than males In females may also get abnormal development of PARAMESONEPHRIC DUCT - ureters enter ~~ vagina ~~ uterus - vaginal or uterine infections |
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URETERS
HYDRO |
Ureters enter and travel a distance in mucosa of bladder
Constricions of Flow cause a Backlog of urine in Ureter - enlarged ureters - enlargement of renal pelvis - impinges on kidney ~~ tf non functional kidney |
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URACUS
PATENT |
aka Persistent
Urachus connects umbilical cord to Bladder - umbilical cord excretes into allantois Normal Development - stretching during rupture of umbilcal cord stimulates urachus to close Abnormal Development - Failure of urachus to close - Umbilical Torsion ~~ causes back flow and enlargement ~~ tf stretch/rupture insufficient to close - Iatrogenic ~~ cut umbilical cord to close to abdomen ~~ tf insufficent space for development of necrotic tissue in urachus - Aquired ~~ Naval Ill aka Omphalophlebitis ~~ urachus becomes infected ~~ tf opens from inflammation Presentation - urine from urachus |
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URACHUS
PATENT INTERNAL |
Urachus closes extenally but open internally
Iatrogenic - cut to close Presentation similar to ruptured bladder ~~ Enlarged Abdomen ~~ Depression ~~ Urine in Abdomen |
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REPRODUCTIVE SYSTEM
DEVELOPMENT HOW DOES IT START |
With great INDIFFERENCE
Complex hormonal interactions determine sex - ie if you say testosterone she will cut your head off see previous material It all starts with GERM cells in the Yolk Sac - migrate via GIT to GENITAL RIDGE ~~ during mesonephric stage when Genital Ridge bulges into coelum - take up residence forming primative sex cords - eventually form sperm or ova Primative Cords - in males form semineferous tubules ~~ incomplete at partuition ~~ complete development at sexual maturity - in females form supporting cells for ova ~~ germ cell and folicle proliferation complete (just for this course) by partuition |
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REPRODUCTIVE SYSTEM
DEVELOPMENT DANCE OF THE DUCTS |
MESONEPHRIC DUCT
- Male Reproductive System ~~ Edididimus ~~ Ductus Deferens ~~ Penile and Pelvic Urethra - Female Reproductive System ~~ degenerates leaving hole which becomes supporting structure for reproductive tract ~~~~ Mesovarium ~~~~ Salpinx ~~~~ Mesometrium PARAMESONEPHRIC DUCTS - condense out of Mesochyme - Male Reproductive System ~~ degenerates ~~~~ sometimes leaves a tiny little uterus ~~~~~~ maybe Hershel will get lucky - Female Reproductive System ~~ migrate together and fuse forming Uterus ~~ degree of fusion is species dependent ~~ degree of fusion is proportional to size of Body of Uterus ~~ region that does not fuse forms horns of uterus ~~ fusion produces ~~~~ Cervix ~~~~ Cranial 1/3 of Vagina ~~~~ Rabbits have little fusion ~~~~~~ tf double cervix |
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VAGINA
DEVELOPMENT |
Caudal 2/3 develops from VAGINAL PLATE region of UROGENITAL SINUS
Vaginal Plate grows towards cranial 1/3 of vagina - lumen forms when Vaginal Plate reaches cranial vagina - vaginal plate regresses at Wall of Urogenital Sinus - remenant of Vaginal Plate froms - Hymen |
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DOUBLE VAGINA
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Incomplete migration and fusion of Paramesonephric Ducts
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GUBERNACULUM
DEVELOPMENT REMEMBER SHE THINKS THIS ONE IS NEAT |
Condensation of mesenchyme within INGUINAL FOLD
Testosterone and other Gonadotropins cause swelling of Gubernaculum - enlarges Inguinal Canal Later in male development - Scrotal Swellings develop - gubernaculum dehydrates ~~ creates space in inguinal canal ~~ tf allows passive movement of Testis into Inquinal Canal - but Testis are TOO LARGE to pass Increase in Abdominal Pressure - required to pass testis through Inquinal Canal - usually supplied during partition ~~ this is the "neat" part - testis can also be pushed into scrotum post partuition via coughing etc - some species move testis in and out of inguinal canal through out life - ie Rodents - Sumo Wrestlers ~~ according to Stu |
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CRYPTOCHIDISM
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Testis Retained in Abdominal Cavity
- absence of testosterone - low levels of signalling receptors Genetic Associations |
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GENITALIA
EXTERNAL HOW MANY SWELLINGS |
Genitital Tubercle
- Saggital Plane - Male ~~ Elongation to form Phallus - Female ~~ Regression to form Clitoris - Urethra ~~ ventral Urethral Fissure ~~ remains open in early development ~~ closes ventrally in later development to form Urethra ~~~~ ie during phallic elongation stage Genital (aka Labial) Swellings - bilaterally adjacent to Genital Tubercle - Male ~~ Scrotum - Female ~~ Labia Urogentital Folds - Bilateral - lateral to Genital Swellings |
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HYPOSPADIA
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Incomplete closure of Urethral Fissure
Genetic Associations - note less extreme malformations capable of reproduction |
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HERMAPHRODITISM
TYPES |
INTERSEX
- having both male and female genetalia TRUE HERMAPHRODITE - both male and female genetalia - Presence of BOTH male and female Gonads ~~ via presence of ovatestis ~~~~ ie ovarian and testicular tissue in one structure ~~ or via presence of both ovaries and testis PSEUDOHERMAPHRODITE - Chromaosomal and Gonadal Sex in Agreement - External or Internal Genitalia are Ambiguous ~~ ie one or more structures of NON-Chromosomal sex |
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HERMAPHRODITISM
MECHANISAM |
Androgen Insensitiviy
Defect of Androgen Receptor Gene on X chromosome Receptors - do not bind Androgens - or binds but does not function properly Results in Varying Degrees of FEMINIZATION |
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TESTICULAR FEMINIZATION
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Animals that are XY Chromosomally
Testosterone Production and Conversion to Dihydrotestosterone are Normal Androgen Receptor gene on X chromosome defective - tf Androgen Receptors do not bind or do not function properly Results in Lack of Androgen Dependent Masculinization - tf animals have ~~ External Female Secondary Sex Characteristics ~~ No Uterus ~~ Internal Testis that lack Epididymis ~~~~ Note main structure of Testis due to SRY gene ~~ No male structures that dervive from Paramesonephric Duct ~~~~ Vas Deferens ~~~~ Epididymis Presentation - infertile - failure to cycle - stallion like behaviour |
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INTERSEX
POLLED GOATS |
Polled is Dominant Trait
- pp horned - Pp polled and fertile PP - Male ~~ polled ~~ intersex ~~ 50% are infertile - Female ~~ polled ~~ intersex ~~ 100% infertile |
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SEGEMTAL APLASIA OF PARAMESONEPHRIC DUCT
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aka White Heifer Disease
- mismonmer ~~ originally observered in Herford Short Horns ~~ Rr Roan ~~ RR White with high incidence of Segmental Aplasia - Mainly Cattle - also Horses, Cats, Dogs, Pigs, Sheep and Camelids Abnomality of Female Reproductive Tract - arrest during development of Paramesonephric Duct ~~ via disruption of blood supply during development - tf segmented development of any or multiple sections of reproductive tract - defects ~~ Vagina ~~ Cervix ~~ Uterus ~~ Uterine Tubes - OVARIES ARE NORMAL ABSENT HORN - one side of Paramesonephric Duct failed to develop normally - low fertility but may breed normally DOUBLE CERVIX - Incomplete Fusion of Paramesonephric Ducts - Fertile - High incidence of Dystocia - Cervix susceptable to tearing APLASIA OF LOWER HORN - Segment of Paramesonephric Duct did not develop normally - remainder of Paramesonephric Duct did - Upper portion of Horn SWOLLEN ~~ fluid produced by uterus cannot drain through APLASTIC SEGEMENT to vagina - decreased fertility |
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SEGMENTAL APLASIA OF PARMESONEPHRIC DUCT
3 PRESENTATIONS |
ABSENT HORN
- one side of Paramesonephric Duct failed to develop normally - low fertility but may breed normally DOUBLE CERVIX - Incomplete Fusion of Paramesonephric Ducts - Fertile - High incidence of Dystocia - Cervix susceptable to tearing APLASIA OF LOWER HORN - Segment of Paramesonephric Duct did not develop normally - remainder of Paramesonephric Duct did - Upper portion of Horn SWOLLEN ~~ fluid produced by uterus cannot drain through APLASTIC SEGEMENT to vagina - decreased fertility |
