Nervous system - pathology exam

HYPOMYELINATION

• Too little myelin is produced

• The Myelin sheath is thinner than normal because Schwann cells (PNS) or Oligodendrocytes (CNS) cannot produce enough myelin

• As a result, nerve impulses travel more slowly

DYSMYELINATION

• Myelin is made, but it is formed incorrectly

• Instead of wrapping neatly around the axon, the myelin becomes thin, irregular, or distorted, making nerve conduction inefficient

DEMYELINATION

• Lost or destroyed after it has already formed

• Without myelin, nerve signals become slow or may stop completely

VASOGENIC EDEMA

• Most common type of cerebral edema in animals

• It occurs when the blood-brain barrier (BBB) is damaged, allowing fluid, proteins, ions and other plasms components to leak from blood vessels into the extracellular space especially in the white matter

CYTOTOXIC EDEMA

The intracellular accumulation of fluid within brain cells; unlike vasogenic edema, where fluid accumulates

PARESTHESIA

An abnormal skin sensation, such as tingling, itching, or burning; usually caused by peripheral nerve damage

CAUDAL DISPLACEMENT

Forward or backward movement causes the brain to strike the inside of the skull, producing bruising (contusions)

IMPACT (COUP)

Injury occurs at the site where the head is struck

REPERCUSSION (COUNTERCOUP)

The brain rebounds and strikes the opposite side of the skull, causing injury opposite to the impact site

LISSENCEPHALY

• Developmental anomalies that result in part of or the entire cerebrum having smooth surfaces lacking normal gyri and sulci

• Abnormal development of nerve cells in the brain before birth

RATHKE’S CLEFT CYSTS

Cystic lesions filled with clear fluid; which leads to panhypopituitarism (stunted growth, bilateral alopecia, come done, and skin hyperpigmentation)

HYDROCEPHALUS

Excessive accumulation of cerebrospinal fluid (CSF) within the brain’s ventricles

1. CONGENITAL HYDROCEPHALUS

2. ACQUIRED HYDROCEPHALUS

2 Types of hydrocephalus

CEREBELLAR HYPOPLASIA

Underdevelopment of the cerebellum due to the loss of developing nerve cells

DYSRAPHISM

Congenital failure in the fusion or formation of the primitive neural tube in the developing embryo

ANENCEPHALY

Congenital absence of most of the brain, especially the cerebral hemispheres

PROSENCEPHALIC HYPOPLASIA

Only the forebrain is absent

CRANIAL BIFIDUM

• Congenital failure of the skull bones to fuse, leaving a midline cranial defect

• This opening allows the meninges and /or brain tissue to protrude

WALLERIAN DEGENERATION

The active breakdown of an axon and its myelin sheath following a cut or crush of a nerve fiber

LEUKOENCEPHALOMALACIA

Ingesting moldy corn feed contaminated with Fusarium moniliform a fatal neurologic disease in horses

SYRINGOMYELIA

A condition characterized by the formation of a cavity within the spinal cord

ACRAL MUTILATION SYDROME

A congenital sensory neuropathy characterized by loss of pain sensation (analgesia) and self-mutilation due to degeneration of sensory neurons