Developmental malformations Flashcards
(107 cards)
1
Q
- an individual is said to be unique in every aspect and this is determined by the
______ in the chromosome
A
genes
2
Q
- is hereditary when the defect of one parent is transmitted in the gametes through the generations
A
defects
3
Q
- simply imply that the individual is born with the defect and has no reference to it being hereditary or not..
A
congenital defects
4
Q
he showed that although some traits are transmitted to generation of offspring in an unchanged state, the physical expression of a trait differed from genetic constitution
A
gregor mendel
5
Q
- a unit of genetic information (gene) is transmitted unchanged from generation to generation.
A
first law
6
Q
– alternate forms of the gene must segregate during gamete formation and recombine independently in the offspring to provide a 1:2:1
ratio.
A
second law
7
Q
- This alternate form of gene was later called ______, and its transmission outlined
the concepts of dominance and recessivity
A
allele
8
Q
- non-allelic traits do not segregate but assort randomly* and recombine with a probability representing the product of their independent probabilities.
A
third law
9
Q
- is the most commonly reported genetic defect in domestic animal species, compared to humans where autosomal dominant inheritance was reported to account for most cases.
A
Autosomal Recessive Inheritance-
10
Q
- contains a pair of identical alleles of a given gene,
A
homozygous individual
11
Q
- contains different alleles for a given gene.
A
heterozygous individual
12
Q
if a heterozygous affected animal mates with a homozygous animal; each offspring has 50% risk of being affected
A
Autosomal dominant inheritance
13
Q
- Most defects caused by autosomal dominant inheritance exhibit ?
A
distinct phenotypic defects.
14
Q
- Cases reported in farm animals that are expressed by autosomal dominant inheritance includ
A
- idiopathic epilepsy,
- familial convulsion in cattle.
15
Q
- The defects reside on either the X chromosome or the Y chromosome of the individual.
A
Sex linked inheritance
16
Q
- an individual with possessing only one allele
A
hemizygous
17
Q
- In humans the diploid number is 46. In gametes however, the haploid number is 23 and includes one of each pair
A
chromosomal inheritance
18
Q
chromosomal inheritance occurs in 2 types:
A
- numerical abnormality
- structural abnormality
19
Q
- Abnormalities in the number of chromosomes called “heteroploid”
A
numerical abnormality
20
Q
- When an individual is born and carries with its multiples of the haploid number of its
chromosomes.
A
polyploidy
21
Q
- the number may be 69
A
triploidy
22
Q
- the number may be 92
A
tetraploidy
23
Q
- involves either an increase or decrease in the normal number of chromosomes without regard to completion of the full haploid set. (involved in somatic chromosomes)
A
Aneuploidy
24
Q
- If there are three sex chromosomes instead of
two (e.g.,XXY, or XYY), the condition is called
A
Trisomy
25
- if only one sex chromosome occurs (e.g., OX,
OY), the condition is called
monosomy
26
- occurs as a result of ***nondisjunction of chromosomes*** during the anaphase stage in meiosis of germ cells or in mitosis at the zygote,
heteroploidy
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- heteroploidy result to?
1. mosaicism
2. chimerism
28
- presence of ***two or more*** populations of cells with different genotypes.
mosaicism
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- common in fraternal twinning, fetal ***sharing of circulation*** results in populations of cells between twins, resulting in the presence of different genotypes in the cell population in one twin
chimerism
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- animals, particularly in fraternal twinning (male and female twin) in
cattle, sheep & goats
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- In humans, defects in sex chromosome number are called
gonadal dysgenesis,
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- could occur at the chromosome and be expressed in the individual.
structural abnormalities
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- where the fragment becomes attached to another chromosome.
translocation
34
- Sometimes, parts of the chromosome exchange places with another and is called
reciprocal translocation
35
________ is observe in humans, there may be chromosomal deletion where a piece of the chromosome is missing,
down syndrome
36
________ where two breaks occur and
a realignment results in a ***reversal*** of the order of the chromosome
inversion of chromosomes
37
- When a defect is ***governed by the additive effect*** of two or more genes of small effect but is conditioned by non-genetic environmental influences and is expressed
polygenic inheritance
38
- is a defect where there is a ***deficiency of insulin***, and therefore occurs as persistent hyperglycemia (increased blood sugar levels).
diabetes millitus
39
6 mutant genes of large effects :
1. Autosomal Recessive Inheritance
2. Autosomal dominant inheritance
3. Sex linked inheritance
4. Chromosomal inheritance
5. Structural abnormalities
6. Polygenic inheritance
40
- involves a seemingly endless list of unrelated syndromes whose causes are to be found in the ***ambiguous borderland*** between environment and genetics.
congenital defects
41
- study of congenital malformations
teratology
42
- Many are acquired in utero when differentiating cells are destroyed or altered by
agents known as
teratogens
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are agents that affect developing cells and tissue altering its structure, genetic constitution
teratogens
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As with other causes of disease, teratogens may be grouped under the following categories:
1. physical agents
2. chemical agents
3. biological agents
45
Agents often implicated in cases of congenital malformation:
1. drugs
2. viruses
3. plant toxins
46
a drug released in the 60’s to relieve nausea during pregnancy in humans is the most studied teratogenic agent that causes Amelia (absence of limbs) in affected humans.
thalidomide
47
a twin joined at some portions of the body, with both twins presenting complete parts.
Symmetrical conjoined twin
48
Symmetrical conjoined twin is also called _______
siamese twins
49
in symmetrical conjoined twin the basic mechanism for their formation is:
splitting of the zygote ⇒resulting in two blastoderms developing
from a single ovum.
49
3 plant toxins
1. coniine and gamma coniceine from Conium maculatum
2. nicotine from Nicotiana tabacum,
3. undefined alkaloid from Veratrum californicum
50
-joined at the thorax
thoracopagus
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- joined at the ilium of pelvis
ileoopagus
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- joined at ischium of pelvis
ischiopagus
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The attached malformed part of the twin is called a ?
PARASITE
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twins joined in some portions of the body, but one twin may be incompletely developed. malformation is a result of problems in placental circulation with
compression of umbilical vessels of one of the twins
Asymmetrical conjoined twins
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a twin presented without body form and
heart.
Acardius amorphous
53
- a conjoined twin presenting two distinct bodies, united to a common point,
but one of the twins is incompletely developed.
DUPLICATION OF PARTS
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- mechanism of duplication of parts
constriction of the blastula or gastrula causes this malformation.
55
example of duplication:
dicephalus monster
dipygus monster
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with two heads
dicephalus monster
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with two hind parts
dipygus monster
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– imperfect closure of vertebra
Spina bifida
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- failure of the brain to develop
Anencephaly
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– imperfect closure of the cranium
Cranioschisis
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- brain tissue protrudes in a hole of the skull
Cephalocele
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59
- cerebrospinal fluid is produced but not drained
Hydrocephalus
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- dilatation of the central spinal canal
hydromyelia
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- complete failure of the spinal cord development
Amyelia
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- cavitations of the spinal cord
Syringomyelia
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structures fail to fuse at median plane:
❖ palatoschisis –open palate;
❖ cheiloschisis – slit upper lip;
❖ Cleft nose– split nose
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Structuters failed to develop
❖ cyclopia or cebocephaly
❖ aprosopus .
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a developmental defect of frontal and nasal bones
with two eyes developing in one socket;
cyclopia or cebocephaly
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failure of the facial structures to develop)
aprosopus
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Also included are defects in the development of the jaws
❖ agnathia
❖ micrognathia
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basic mechanism includes strangulation of the developing limb with umbilical vessels leading to amputation or fusion
Abnormalities in Hind Limbs
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– absence of lower jaw,
agnathia
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– very small jaw
micrognathia
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abnormalities in hind limbs such as:
❖ sympodia
❖ symelia
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– failure of limb development
sympodia
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- fused hindlimbs.
symelia
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failure of fusion or development of the ventral body wall, includes such defects as:
❖ thoracoschisis
❖ omphaloschisis
❖ gastroschisis
❖ schistosomus reflexus
74
– sternal fissure
thoracoschisis
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– opening at umbilicus
omphaloschisis
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opened walls of stomach
gastroschisis
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incomplete development of ventral body walls where
affected animals show exposed visceral organs.
schistosomus reflexus
78
Abnormalities in Tissues or Organs, common examples include:
❖ persistent foramen ovale in the heart,
❖ Atresia ani
❖ intersex or hermaphroditism
79
no anal opening
Atresia ani
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a female born co-twin to a male that has altered
gonadal development due to blood exchanges in utero
intersex or hermaphroditism
81
Includes defects in bone formation such as seen in:
❖ Achondroplasia
❖ Chondrodystrophia
82
- where they occur failure of cartilage formation and subsequent
improper ossification ⇒ resulting to short limbs
Achondroplasia
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- fetalis where the skeleton is missing or failed to develop.
Chondrodystrophia
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are abnormal mixtures of tissues indigenous to their location
hamartomas
85
example of hamartomas
❖ nevus or mole;
❖ Angioma
❖ Lipoma
86
in that the latter consist of tissues that are foreign to the area
teratoma
87
is a disease in which an animal is born with flexed, absolutely
rigid limbs but this is a primary problem not with bones or joints but rather with innervation of muscles because of "dysraphism" in the spinal cord.
Arthrogryposis
88
congenital porphyria for what animals?
Cattle & pig
89
Familial polycythemia for what speciific animal?
cattle
90
Inheretied goitre for ?
sheep
91
combine immunodeficiency is for?
horse
92
Chediak-Higashi syndrome is for?
Cattle & horse
93
atresia ani common in?
pig
94
congenital hydrocephalus is for ?
cattle
95
cranium bifidum
pig
96
Cerebellar hypoplasia is for?
cattle
97
Cerebellar atrophy most common in?
sheep
98
Congenital tremor for?
pig
