Neuropathology Flashcards
What are the components of the CNS?
- Neurons
- glial cells
- white matter tracts
- grey matter
What are the 3 cell types of glial cells?
- Astroglia (support)
- Oligodendrocytes (myelin)
- Microglia (phagocytes)
What are the components of the meninges?
- Dura matter - tough connective tissue
- Leptomeninges (Arachnoid mater CSF and pia mater
What are the components of the grey matter?
- Neuronal cell bodies
- neouropil-axons and dendrites
- Neuroglia
What are the components of the white matter?
- Fasicles/bundles of neuron fibres (axons and myelin sheath)
- Neuroglia
What is the structure and function of neurons?
- Generation, conduction and trasnmission of impulses
- Large cells: dendrites, cell body and axon. NOTE: different shapes, sizes and arrengement
- Neuropil
- axonal transport
What is the structure and function of glial cells?
- Astrocytes - monitor and regulate fluid and electrolyte balance, remove excessive release of neurotransmitters in synapses, inflamm and immune responses, repair
- Oligodendrocytes - form myelin sheath
- microglia - resident phagocytes
What is the structure and function of ependyma?
- A single layer of usually ciliated columnar cells lines the ventricles, mesencephalic aqueduct and central canal of the spinal cord
- Allows for the regulated bidirectional flow of proteins and fluid between the ventricles and the interstitial space of the brain
What is the structure and function of the choroid plexus?
- Evagination of blood vessels covered by modified ependymal cells
- Specific sites within the lateral, third and fourth ventricles
- Secrete CSF that fills both the ventricular system and subarachnoid space
What is the structure and function of the meninges?
- Dura mater - Fibrous outer capsule, Epidural space on the spinal cord, but continuum with the periosteum in the brain, Pathological situations may lead to formation of subdural spaces
- Aracnoid - contains CSF, subarachnoid space communicate with ventricles, protection against trauma
- Pia mater - clings to the CNS surface, prolongtions of astrocytes
What are the portals of entry into the CNS?
- Direct extention (trauma, ear infection, extensionof nasal cavity or sinus, extension of osteomyelitis, neoplastic processes)
- Haematogenous (most common)
- Leukocytic trafficking (immunological surveillance, migration of macrophages or lymphocytes containing microorganisms)
- Retrograde axonal transport (transported from the periphery into the CNS by neuronal retrograde flow, pathogens that replicate in tissues richly innervated, connection between peripheral infection and the CNS)
What are the defence mechanisms of the CNS?
- Skin, bone, meninges, CSF
- Barriers -> BBB, glia limitans, blood CSF barrier, CSF brain barrier
- innate immunity and adaptive immunity
Name the 12 crainial nerves
OOOTTAFVHVAH
I: Olfactory
II: Optic
III: Oculomotor
IV: Trochlear
V: Trigeminal
VI: Abducent
VII: Facial
VIII: Vestibulocochlear
IX: Glossopharyngeal
X: Vagus
XI: Accessory
XII: Hypoglossal
What does the severity of clinical signs depend on?
Depends on the location and severity of damage
QUESITONS FROM NEUROANATOMICAL LOCATIONS OF LESIONS
What are the types of inflammatory exudates of the CNS?
- Suppurative
- Non-suppurative
- Granulomatous
- Fibrinous
What word would you use to describe meningeal inflammation?
Meningitis
What word would you use to describe parenchymal inflammation?
encephalitis
What word would you use to describe both meningeal and parenchymal inflammation?
meningoencephalitis
What are the infectious agents involved in CNS inflammation?
- Virus (rabies, canine distemper)
- Bacteria
- Algae
- amobae
- protozoa
- metazoa
- prions
What are the non-infectious agents associated with CNS inflammation?
- Idiopathic
- foreign bodies
What are the routes of entry that lead to CNS inflammatory diseases?
- Haematogenous
- Direct extension
Provide some examples of degenerative diseases of the CNS
- Storage diseases
- Craniopharyngiomas
- Cysts
- IV disc protrusion
- Trauma
- Polioencephalomalacia of ruminants
- Thiamine deficiency in cats
What is malacia?
Areas of brain necrosis
Malacia = softening
What is malacia mostly associated with?
Toxins
What are the circulatory disturbances associated with the CNS?
- Oedema (vasogenic, cytotoxic, intersitital)
- Infarction and ishaemia
- Haemorrhage/haematoma
What is the most common form of oedema?
Vasogenic - caused by injuries (trauma, inflamm, infarc, hypertension). Mainly in white matter. Microscopically we see pale aras with separation of myelinated axons by vacuolated spaces
What are some examples of neoplastic disorders of growth?
Primary
- Ependymoma
- meningioma
- oligodendrocytoma
- astrocytoma
- pituitary adenoma
Metastatic
- lymphosarcoma
- haemangiosarcoma
