Term
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Definition
-an organism in the early stages of development
-has not acquired an anatomical form that is readily recognizavle in appearance as a member of a specific species |
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Term
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Definition
| -potential offspring wihtin the uterus that is generally recognizable as a member of a given species |
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Term
| Briefly define differentiation |
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Definition
| -unspecialized cells => recognizable groups of cells that have a common function |
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Term
| Describe how an embryo starts and what it eventually becomes in general terms. |
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Definition
| -the embryo starts as a mass of pluripotent cells that eventually form cell layers and will differentiate into the embryo proper and placenta |
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Term
| What does the endoderm eventually become? Mesoderm? Ectoderm? |
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Definition
-Endoderm: digestive system, lungs, endocrine system
-Mesoderm: muscle, skeleton, CV, repro system
-Ectoderm: nervous system, skin, hair |
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Term
| What of the structures that the ectoderm becomes are of primary concern? Secondary concern? |
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Definition
-Primary concern: repro tract, mammary glands, nervous system
-Secondary concern: oral and nasal cavities, skin, hair, nails, sweat glands |
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Term
| Which of the structures that the mesoderm becomes are of primary concern? Secondary concern? |
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Definition
-Primary concern: Gonads, uterus, cervix, cranial vagina, epididymis, ductus deferens, accessory sex glands
-Secondary concerns: muscle, blood vessels, urinary system, skeletal system |
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Term
| Is the endoderm of primary or secondary concern? |
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Definition
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Term
| What is the critical point of embryonic development? |
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Definition
| -the point at which it switches from being supported by a yolk sac and being supported by the allantochorion |
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Term
| Does Organogenesis occur inside or outside the embryo? |
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Definition
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Term
| From what tissue does the anterior lobe of the pituitary galand (adenhohypophysis) form? What does it produce? How is it connected to the hypothalamus? |
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Definition
-roof of the mouth
-GH, TSH, ACTH, PRL, FSH, LH, beta-endorphin, leptic
-connected to the hypothalamus via the portal system |
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Term
| From what tissue does the posterior logy of the pituitary gland arise (neurohyphophysis)? What does it produce? How is it connected to the hypothalamus? |
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Definition
-brain tissue
-oxytocin, ADH, VP, etc
-connected to hypothalamus via neuronal axons |
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Term
| Definition: Sex differentiation |
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Definition
| -process whereby a group of unspecialized cells develops into a functional recognizable group of cell that have a comon function |
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Term
| Definition: Sex determination |
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Definition
| -syste that determines the sxual characteristics of an organism which generally consists of genetic (allels or genes) or hormonal parameters |
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Term
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Definition
| -th chromosomal complement of an organism (number of chromosomes, XX or XY) |
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Term
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Definition
| -the genetics of an organism |
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Term
Definition: Phenotype
-What controls its expression? |
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Definition
-the observed characteristics such as morphology, developent, blood types, behavior, etc
-expression depends on genotype and envrionment |
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Term
| Sexual differentiation depends on what 3 stages? |
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Definition
1. Chromosomal sex (karyotype): determened by type of sex chromosome contributed by the sperm
2. Gonadal sex: determined by the Sry gene that induces testes formation
3. Phenotypic sex: determined by substances produced in male testes that causes regression of female tract and formation of male tract |
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Term
| What happens during the sexually indifferent stage? |
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Definition
| -primordial germ cells mibrate from outside the organism (yolk sac) into the organism through the hindgut to the undifferentiated gonal just within the dorsal body wall (aka genital ridge) |
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Term
| What happens to the pronephros? |
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Definition
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Term
| What becomes of the mesonephros in the male and female? |
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Definition
-Male: form efferent ducts
-Female: regress |
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Term
| What becomes of the metanephros in the male and female? |
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Definition
| -becomes funcitonal kidney |
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Term
| What becomes of the mesonephric deucts in the male and female? |
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Definition
-aka Wolffian ducts
-Male: epididymis and ductus deferens
-Female: regress or become parovarian cysts |
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Term
| What becomes of the paramesonephric ducts in the male and female? |
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Definition
-aka Mullerian ducts
-Male: regress
-Female: uterus and oviducts and cranial vagina |
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Term
| What becomes of the primitive sex cords in the male nad female? |
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Definition
-Male: semineferous tubules
-Female: regress, primitive follicular cells |
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Term
| What becomes of the primitive germ cells in the male and female? |
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Definition
-Male: spermatogonia
-Female/l oocysts |
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Term
| What does the determination of physical sex organ characteristics rely on? |
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Definition
-presence of Testis Determining Gactor to encoroughe the development of testes
-Anti-mullerian hormone: cuases degeneration of paramesoephric duct
-lastly the presence of Dihydrotestosterone: causes differentiation of penis, scrotum, and accessor sex glands |
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Term
| Which cells produce anti-mullerian hormone? |
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Definition
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Term
| What is the basic outline of sex differentiation? |
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Definition
| -chromosomal sex => genetic factors => gonadal sex => phenotypic sex |
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Term
In the developing female, where are the gonads in the following species:
a) bitch
b) queen
c) cow
d) mare |
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Definition
a) caudal to kidney but cranial to bladder
b) same as bitch
c) down (also in doe and ewe)
d) up |
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Term
| What happens during the fetal stage that is male-specific? |
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Definition
| -testicles descend into the scrotum |
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Term
| What happens during the fetal stage that is specific to the female? |
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Definition
-broad ligament development
-ovaries migrate caudally due to fetal growth |
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Term
| Explain the external differentiation of the male. |
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Definition
| -start at indifferent stage => presence of DHT cuases scrotum to form and the penis to surround the urethral groove from the genital tubercle |
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Term
| Describe external differentiation in te famle. |
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Definition
| -indifferent stage without the presence of DHT cuases the minora and majora labia to form around the vulvar cleft and the clitoris to form from the genital tubercle |
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Term
| Describe what happens during the transabdominal phase of testicular descent. |
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Definition
-cells of the peritoneum infiltrate the gubernaculum in the infuinal region and fuse wiht it
-this fusion allows the vaginal process to form as the distal gubernaculum growns into the scrotal region |
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Term
| Describe what happens during the inguinal-scrotal phase of testicular descent. |
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Definition
| -gubernaculum enters the inguinal ring => rapid growth phase of the ubernaculum within the scrotum => mechanically moves the testes into the inguinal ring |
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Term
| The rapid growth pahse of the gubernaculum during the inguinal-scrotal phase of testicular descent is dependent on what hormone? |
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Definition
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Term
| What happens during the Inguinal-scrotal phase II of testicular descent? |
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Definition
-gubernaculum in the scrotum shrinks and the testes move from the inguinal ring region into the scrotum
-helphed by pressure from visceral growth |
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Term
| What happens during inguinal-scrotal phase III during testicular descent? |
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Definition
| -gubernaculum continues to shrink => pulls testes deeper into scrotum => causes a complete encapsulation of each testies within the visceral vaginal tunic and gubernaculum becomes the scrotal ligament |
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Term
| What is the most common congenital defect of the testes ind ogs? |
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Definition
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Term
| How is cryptorchidism heritable? |
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Definition
| -sex-limited autosomal recessive trait |
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Term
| HOw do we diagnose in puppies and kittens? |
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Definition
| -history, palpation, AMH serum levels |
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Term
| What is the most common tumor in the descended testicle? What clinical signs does it cause? |
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Definition
-Sertoli cell tumor
-prepucial swelling, bilateral alopecia, lots of estrogen |
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Term
| What is the most common tumor of the retained testicle? |
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Definition
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