Unit 4 - 4.1 and 4.2 Flashcards
Complete failure of an organ or tissue to develop. The organ is totally absent.
Agenesis and aplasia
Failure of an organ to achieve the full size for the age and stage of development of that particular animal.
Hypoplasia
The cause of most developmental defects is unknown. Some causes that may contribute to defects are:
- hereditary faults
- somatic mutation
- stresses or injury
What causes cyclopia in lambs?
Veratrum californicum
What type of malnutrition causes blindness?
vitamin A deficiency
What type of malnutrition causes hairlessness?
iodine deficiency
What are the effects of hypoplasia and/or agenesis?
highly variable depending on time of injury, degree of defectiveness, and the organ involved
deviations from normal as it applies to tissues:
anomalies
refers to the degree of cell proliferation:
-plasia
refers to a change in the over cell/tissue size:
-ophy
What do you call it when the kidney completely fails to develop?
- agenesis of the kidney OR
2. (unilateral) renal agenesis
When is the only time you expect to find agenesis in an adult, living animal?
when the agenesis involves only ONE of a pair of organs
When do these developmental anomalies (i.e. agenesis) occur?
very early in development
Why does something like agenesis occur?
due to loss or severe damage to embryonal tissues
= no development at all
agenesis
What do you call it when the cerebellum has started to develop but never reached its full potential?
cerebellar hypoplasia
What’s a common cause of hypoplasia in cats? Cows?
feline panleukopenia (vx/dz); BVD (vx/dz)
a lesion characterized by the presence of a miniature, abnormal globe in a relatively normal-size orbit:
mirophthalmia
What is one of the major issues with cryptorchid testicles?
never reaches its full size potential
Since the cryptorchid testicle began to develop normally, but never fully developed, we call it:
testicular hypoplasia (unilateral)
What happens with cryptorchid testicles that make them incapable of functioning normally?
body temp heat prevents spermatogenesis
An acquired condition that brings about a decrease in the size of a normally developed cell, tissue, or organ:
atrophy
What are two decreases that can cause atrophy?
- cell size
2. cell number
What do all causes of atrophy have in common?
- a deficient blood or lymphatic circulation or
- an increased metabolic activity that leads to enzymatic destruction of cell substance
the type of atrophy that is usually associated with the aging process:
physiologic
Give an example of physiologic atrophy that occurs following parturition and lactation:
involution and of the uterus and mammary glands
Generalized reduction in size of body tissue as the body stores become depleted due to starvation or subsequent to general physical wasting and malnutrition associated with chronic disease.
Cachexia atrophy
A term associated with the atrophic changes in fatty tissues associated with starvation (a type of cachexic atrophy):
serous atrophy of fat
Atrophy characterized by a localized reduction in the size of an organ or tissue due to interference with the local blood vascular supply
vascular or ischemic atrophy
What are two causes of vascular/ischemic atrophy?
- internal narrowing
2. external compression
Organs that are dependent upon hormonal stimulation to maintain their normal structure and function will decrease in size when this trophic influence is interrupted:
Endocrine atrophy
What can cause endocrine atrophy via a reduction in size in accessory glands?
castration
How does endocrine therapy cause endocrine atrophy?
corticosteriods can cause a reduction in the size of the renal cortex
When certain endocrine glands start producing less hormone and thus lose size. (i.e. adrenal cortex):
hypopituitarism
Increased demands on organs, particularly endocrine organs, may at first be followed by enlargement, but if the demands are prolonged to the point of overwork, atrophy may result.
Exhaustion atrophy
What is a likely cause of exhaustion atrophy?
buildip of catabolic enzyme sin the presence of accumulating acid metabolites
When an organ or tissue is immobilized or is forced to cease functioning it will decrease in size:
disuse atrophy
What’s a perfect example of disuse atrophy?
broken leg in a cast or paralysis of a muscle due to a nerve injury
The persistent displacement of tissue by constant pressure may leas to a reduction in size of the tissues immediately affected:
pressure atrophy
List some common causes of pressure atrophy (5):
- NAG
- Blocked ducts
- hydrocephalus
- Fluid in body cavities
- certain deficiency diseases
How does NAG cause pressure atrophy?
via direct pressure on the tissue itself or indirectly due to pressure on the blood supply
How does vitamin A deficiency cause pressure atrophy?
slows bone development in skull and results in pressure atrophy of optic nerves
The loss of the trophic influence of nerves plus the immobilization of the organ when its nerve supply is lost will lead to atrophy.
denervation atrophy
Atrophic influences of certain diseases like atrophic rhinitis of swine:
infectious/inflammatory atrophy
What is ALWAYS the gross effect of atrophy?
a reduction in size
What stays the SAME during atrophy?
shape and form are maintained
Why may an atrophied tissue/organ be firmer or darker than normal?
because the blood vessels will be close together
Microscopically, what is different about looking at atrophied cells?
smaller (although this may be hard to see)
What type of pigments can sometimes be seen in atrophied livers and hearts?
lipochrome pigment
What do lipochrome pigments do to the heart and liver grossly?
brown appearance (termed brown atrophy)
What type of tissue may replace atrophied tissue in the pancreas and skeletal or heart muscle?
fat
Why may blood vessels appear more numerous in atrophied tissue?
closer proximity - also true grossly
What may happened to the atrophied muscle/tissue depending on the cause, location, and the extent of the atrophy?
loss of function
In glands with atrophy, what must happen before the ducts disappear?
the most specialized cells are removed
Stroma in atrophied organs/tissues is typically spared giving the atrophied organ the appearance of:
too much CT
In order for a cell to shrink, it must lose its:
proteins (via proteolysis)
Used for a cell, tissue, or organ that has reached its full growth potential and then regressed in size:
atrophy
If reduced organ size is due to hypoplasia, then the organ or tissue never:
reached its full size potential
Why does cell number decrease?
apoptosis
What does cell size decrease?
protein degradation exceeds protein synthesis
What are the two pathways for internal degradation of protein?
- phagosome-lysosome pathway (autophagocytosis)
2. ATP-dependent 26S proteosome pathway
In the proteosome pathway, which protein binds to the protein and labels it to be destroyed?
ubiquitin
After labeling the target protein with ubiquitin , what then takes the protein to be destroyed?
26S proteosome
What does the proteosome pathway require?
ATP
What are the two stimuli for a cell to become smaller or disappear?
- inadequate nutrition/oxygen
2. accumulation of catabolic products
Results from an inability of the ureter to drain away urine because of an obstruction in the ureter or distal to it:
hydronephrosis
Pathogenesis for hydronephrosis (5 steps):
obstruction –> pressure build up –> interference with blood and lymph supply/drainage –> accumulation of catabolic products –> cells forced to decrease in size –> renal pelvis expands, cortical/medullary diminish
If you have hydronephrosis of one kidney, how would you expect the other kidney to appear?
hypertrophy and hyperplasia in response to the increased workload
When one organ gets bigger to compensate for another that gets smaller, the condition is referred to as:
compensatory hypertrophy and hyperplasia
When is hydrocephalus most commonly seen in vet med?
young animals with a congenital basis
What are the two major classes of disturbances of cell growth?
congenital, acquired
An increased in the parenchymal mass of a tissue, resulting from an increase in cell size or number, or both:
growth
List 3 examples of controlled growth:
hyperplasia, hypertrophy, metaplasia
List 2 examples of uncontrolled growth:
dysplasia, neoplasia
Alteration of cell form to adapt (metaplasia)
qualitative
increased capacity (hypertrophy, hyperplasia), decreased capacity (atrophy):
quantitative
Common, particularly in the reproductive tract:
agenesis/aplasia
Agenesis/aplasia XY disorders affect:
testis development, androgen synthesis defects,etc.
In the case of disorders of sexual development, rudimentary gonads may develop in these syndromes called __________ or ___________.
dysgenesis; “defective development”
Persistent Mullerian duct syndrome in miniature Schnauzers:
XY males with normal sex organs, often cryptorchid, and a complete paramesonephric system (uterus)
“deficient formation”; failure of an organ to obtain full size:
hypoplasia
Where is hypoplasia often found?
young animals
lack of an orifice:
atresia
narrowing of lumen -
stenosis
When do events of hypoplasia occur?
later in development, usually unknown etiology
a sinus tract leading from one hollow viscus to another
fistula
What are some viral diseases that can congenital cerebellar hypoplasia?
- feline panleukopenia virus
- blue tongue (lambs)
- BVDV (bovine viral diarrhea virus)
What are the two types of hypoplasia?
congenital, hereditary
When do animals usually succumb to hereditary hypoplasia?
in early adult hood
A normal feature of some breeds - LaMancha goats (gopher and elf ears):
auricular hypoplasia (hereditary)
Autosomal dominant trait, normal at bird, develop folding at 3 weeks. Defective cartilage succumbs to gravity. May also have osteohyschondroplasia:
Scottish fold cats (hereditary hypoplasia)
the study of congenital malformations:
teratology
What is the most common congenital CNS abnormality?
hydrocephalus
What are four possible causes on congenital hydrocephaly?
- in utero virus infection
- abnormalities in ependyma or ventricular system
- infection witih blockage of CSF outflow
- parenchyma loss
What happens to the head with congenital hydrocephalus?
doming cranium - bones thin, fontanelles prominent
Ingestion of what plant causes cyclopia in lambs?
Veratrum californicum
