Exam 4: Agenesis/Aplasia, Hypoplasia

Question 1

What are 2 major classes of cell growth?

Answer 1

Congenital

Acquired (after normal development)

Question 2

What is growth?

Answer 2

An increase in the parenchymal mass of a tissue, resulting from an increase in cell size or number, or both

Question 3

What are examples of a controlled response to an abnormal stimulus?

Answer 3

Hypertrophy
Hyperplasia
Metaplasia

Question 4

What are examples of an uncontrolled response to an abnormal stimulus?

Answer 4

Dysplasia

Neoplasia

Question 5

What is necessary to maintain the tissue?

Answer 5

Continued cell proliferation

Question 6

What is quantitative growth?

Answer 6

Increased capacity (hypertroohy, hyperplasia), decreased capacity (atrophy)

Question 7

What is qualitative growth?

Answer 7

Alteration of cell form to adapt (metaplasia)

Question 8

What is agenesis, aplasia, and hypoplasia?

Answer 8

A lack of proper growth potential

Question 9

What does the suffix -plasia mean?

Answer 9

A change in the degree of cell proliferation

Question 10

What does the suffix -ophy mean?

Answer 10

A change in the degree of cell/tissue size

Question 11

Where is agenesis/aplasia common in?

Answer 11

Reproductive tract

Question 12

What are the 3 stages of development?

Answer 12

Chromosomes
Gonad
Tubular structures

Question 13

What are the 4 cell populations that gonads develop from?

Answer 13

Germ (yolk sac)
Mesenchyme (supporting cells)
Coelom epithelium (steroid cells)
Mesonephros epithelium (epithelium)

Question 14

What is agenesis?

Answer 14

“Without beginning”

The complete failure of an organ to develop

Question 15

What is aplasia?

Answer 15

“Without formation”

The organ had a beginnin, but little else-rudimentary nubbin or cord of tissue

Question 16

What determines the development of the gonad?

Answer 16

Chromosomal sex

The absence of the Y chromosome, ovaries form

Question 17

What happens if a Y chromosome is present?

Answer 17

Mullerian inhibiting substance (from sertoli cells) causes regression of the female tract, and testosterone (from interstitial cells) stimulates the Wolffian duct system

Question 18

What does suppressed testosterone lead to?

Answer 18

Aplasia of the male reproductive tract

Question 19

If defects occur in the testosterone target tissue receptor, what does testosterone cause?

Answer 19

Virilization of Wolffian ducts, while dihydrotestosterone induces virilization changes in the urogenital sinus and external genitalia

Question 20

What are common conditions of cell growth disturbance in the reproductive tract?

Answer 20

Failure of normal maturation, hypoplasia, and aplasia of the genitalia
Segmental aplasia of paramesonephric duct

Question 21

What are the 3 main categories of disorders of sexual development with agenesis/aplasia?

Answer 21

Abnormal/missing sex chromosome
Female karyotype
Male karyotype

Question 22

What are examples of abnormal/mixed chromosome?

Answer 22

XXY Klinefelter’s

XX/XY chimerism

Question 23

What are examples of XY disorders?

Answer 23

Testis development

Androgen synthesis defects

Question 24

What are examples of XX disorders?

Answer 24

Ovary development

Androgen excess

Question 25

What is a common example of chimerism in cattle?

Answer 25

Freemartins

Question 26

What are freemartins?

Answer 26

The female twin of the male calf | Vascular anastomoses allows the male calf's gene products to alter the female's phenotype

Question 27

What is a common disorder of sexual development in goats?

Answer 27

XX DSD, SRY - | Phenotypic females with masculinization, often hermaphrodites

Question 28

What does abnormal gonad development drive?

Answer 28

Pehnotypic anomalies, abnormal androgen production, or lack of androgen receptors

Question 29

What happens with male pseudohermaphrodites/testicular feminization/XY sex reversal syndromes?

Answer 29

Androgen receptors are lacking Testosterone is present Female genitalia

Question 30

What happens in miniature Schnauzers with persistent Mullerian duct syndrome?

Answer 30

XY males with normal sex organs, often cryptorchid, and a complete paramesonephric system (uterus)

Question 31

What is hypoplasia?

Answer 31

"Deficient formation" | A failure of an organ to obtain full size

Question 32

What is atresia?

Answer 32

Lack of an orifice

Question 33

What is hypoplasia/stenosis?

Answer 33

Narrowing of lumen

Question 34

What is a fistula?

Answer 34

A sinus tract leading from one hollow viscus to another

Question 35

What is congenital cerebellar hypoplasia?

Answer 35

Neonatal ataxia due to viral infection during pregnancy

Question 36

What are examples of congenital cerebellar hypoplasia?

Answer 36

FPV Bluetongue virus in lambs BVDV in calves

Question 37

Describe what happens with congenital cerebellar hypoplasia?

Answer 37

Germinal layer cells are specifically destroyed and without their migrations the internal granular layer doesn't develop --> cerebellar folia are small and fail to function

Question 38

What are examples of hereditary hypoplasia?

Answer 38

In the pituitary, thyroid, pancreas, kidney | Auricular hypoplasia

Question 39

What is teratology?

Answer 39

A study of congenital malformation

Question 40

What can small defects in tissues lead to?

Answer 40

Large lesions, for examples obstruction of fetal urinary tract leads to hydronephrosis

Question 41

What is the most common congenital CNS abnormality?

Answer 41

Hydrocephalus (water in the head)

Question 42

What is the pathogenesis of hydrocephalus?

Answer 42

Obstruction --> ventricular pressure increases --> ventricles dilate --> ependyma atrophy --> CSF forced into brain --> edema --> degeneration and atrophy of brain --> expansion of ventrciles

Question 43

What diseases are often associated with hydrocephalus?

Answer 43

Panleukopenia virus in cat | Parainfluenza of dogs

Question 44

What is hydranencephaly?

Answer 44

Cavitary anomaly of the cerebral hemispheres, due to tissue necrosis in utero