NP3A

Question 1

Defects present at birth is known as

Answer 1

congenital defect

Question 2

defects can be acquired, caused by agents that destroy rapidly dividing cells

Answer 2

radiomimetic agents

Question 3

What will give rise to the CNS?

Answer 3

Ectoderm

Question 4

_________ development continues into the post-natal period

Answer 4

cerebellar

Question 5

_________ follows the establishment of neuronal networks, and so this too occurs in late gestation and continues into the post-natal period

Answer 5

myelination

Question 6

insults early in gestation will reflect defects in ___________ closure

Answer 6

neural tube

Question 7

What determines outcome?

Answer 7

magnitude and timing of the insult

Question 8

Embryo survives and lesions will impact either the:

Answer 8

• rostral neural tube
• caudal spinal cord and bony encasement

Question 9

forebrain and bony encasement is example of:

Answer 9

rostral neural tube

Question 10

early and severe insult can result in lack of the tissue to form

Answer 10

aplasia

Question 11

early insult that is not as severe can cause

Answer 11

segmental aplasia

Question 12

insults that occur later may allow to form that simply looks smaller

Answer 12

hypoplasia

Question 13

all of the developmental defects will be accompanies by some degree of tissue disorganization at the microscopic level

Answer 13

dysplasia

Question 14

defects in neural tube close are referred to as a

Answer 14

dysraphism
(spinal or cranial dysraphism)

Question 15

malformation of the spinal cord, development defect may be appreciated grossly or only microscopically and the change is described as a

Answer 15

myelodysplasia

Question 16

a congenital defect of the spine in which part of the spinal cord and its meninges are exposed through a gap in the backbone. It often causes paralysis of the lower limbs, and sometimes mental handicap

Answer 16

spina bifida

Question 17

is an umbrella term that describes a number of conditions present at birth that affect the spine, spinal cord, or nerve roots

Answer 17

Spinal dysraphism

Question 18

(spinal cord is out of the body) If we survive that, bacteria are certain to invade the central nervous system since we have a path from the outside world into the spinal cord – a _________________ will follow

Answer 18

suppurative meningomyelitis

Question 19

can cause aplasia, segmental aplasia, or hypoplasia of forebrain components
and we encounter a problem similar to what we encountered with dysraphism of the spinal cord – secondary failure to induce the surrounding mesoderm to form bone.

Answer 19

Cranial Dysraphism

Question 20

A developmental birth defect in which the cranium fails to close completely, so that the brain is exposed to the amnios and eventually degenerates, causing anencephaly

Answer 20

cranioschisis

Question 21

is normally an enteric pathogen, but when entering a developing embryo/fetus, will destroy rapidly dividing cells. This property of killing rapidly dividing cells is what we see with radiation exposure

Answer 21

Bovine Viral Diarrhea virus (BVDv)

Question 22

is a serious birth defect in which a baby is born without parts of the brain and skull

Answer 22

Anencephaly

Question 23

the caudal (posterior) part of the forebrain, containing the epithalamus, thalamus, hypothalamus, ventral thalamus, and the third ventricle.

Answer 23

diencephalon

Question 24

another word for midbrain

Answer 24

mesencephalon

Question 25

Using the BVDv example, and knowing that mean gestation in cattle is approximately
280 days. Exposure at a gestation age of less than 100 days results in:

Answer 25

Fetal Death

Question 26

Using the BVDv example, and knowing that mean gestation in cattle is approximately
280 days. Infections between 100-170 days of gestation cause:

Answer 26

• Cerebral aplasia or hypoplasia, representing infection early in this range
• porencephaly
• cerebellar aplasia or hypoplasia, representing infection early in this range

Question 27

Using the BVDv example, and knowing that mean gestation in cattle is approximately
280 days. Infections between 100-170 days of gestation cause Porencephaly which is:

Answer 27

a defect in a cerebrum that has largely formed, and this would reflect infection during the middle of this range

Question 28

Using the BVDv example, and knowing that mean gestation in cattle is approximately
280 days. The fetus is immune to effects of the virus after _______ days

Answer 28

170

Question 29

This Persian cat (neonate) has a large portion of calvarium that has failed to form, with exposure to brain and meninges. Here, the defects in the forebrain are not grossly apparent, but there was a clear lack of communication between the developing forebrain and the surrounding mesenchymal tissues. This lesion could be caused by:

Answer 29

exposure to a radiomimetic agent (e.g., virus or toxin) or it can be heritable. Breeding history revealed this to be a heritable (autosomal recessive) defect, with variable expression of this lesion in different litters from the same dam.

Question 30

What is the primary functional significance of spina bifida?

Answer 30

Spina bifida predisposes the animal to dynamic spinal cord compression