Nervous System Flashcards
What is Grey Matter?
Where is it located?
region rich in cell bodies but limited numbers of myelinated axons
- peripheral in brain, central in spinal cord
What is White Matter?
Where is it located?
region rich in myelinated axons
- central in brain, peripheral in spinal cord
Which cells are not sensitive to hypoxia?
- microglial cells
- vascular endothelium
What are ganglia?
collection of neurons in the PNS
What are nuclei?
collection of neurons in the CNS
Describe Neuron Soma
- euchromatic nucleus with prominent nucleolis
- Nissl substance in RER and ribosomes
- long lived, so lipofuscin present
What are the possible shapes of the perikaryon and where are each found?
- Pyriform (round, oval): pseudounipolar neurons, Purkinje cells in cerebellum
- Pyramidal: brain cortex
- Stellate: multipolar neuron in spinal cord
Nocioceptors sense what?
pain, itch
Thermoreceptors sense what?
temperature
Meissner’s Corpuscles sense what?
fine touch
Krause Corpuscles sense what?
pressure
Pacinian Corpuscles sense what?
deep pressure
Golgi Organ senses what?
conscious proprioception
- stretching
Muscle Spindles sense what?
conscious proprioception
- muscle stretch and position
Describe Astrocytes
- CNS counterpart of fibroblast
- protoplasmic (grey matter)
- fibrillar (white matter)
What are the functions of Astrocytes?
- transport nutrients
- maintain ECM ion content
- neurotransmitter uptake
- part of blood brain barrier
- antigen presentation
Describe Oligodendrocytes and their function
- small, dark nuclei
- develop and maintain myelin in CNS
Describe Microglia
- resident macrophages of CNS
- smallest cells
- derived from monocytes
- dark elongated nucleus
- mesodermal origin
What are the functions of Microglia?
- phagocytosis of dead cells (Gitter cells) or lipid/myelin (Myeophages)
- antigen presentation
Describe Ependymal cells and their functions
- ciliated cuboidal cells
- line neural cavity, ventricles, choroid plexus, and central canal
- produce CSF
Describe the layers of the Cerebrum
- Pia mater: adherent to surface neutropil
- Subarachnoid space: contains blood vessels
What are Gyri?
elevations in the cerebrum
What are Folia?
elevations in the cerebellum
What are the layers in the Cerebellem cortex?
- Molecular Layer: outer layer, basket cells
- Purkinje cell Layer: middle layer, few Purkinje cells (Ganglionic Layer)
- Granular cell Layer: granule cells
What are the clinical signs in a cat of Cerebellar Hypoplasia
- attention tremors
- hypermetric gait
- ataxia (wide stance)
- relatively normal mentation
What are the regions of grey matter in the spinal cord, and what nerves are present in them?
- dorsal horns: sensory
- lateral horns: autonomic
- ventral horns: motor
What are the Meninges of the Spinal cord?
- Dura mater: thick outer covering
- Arachnoid: membrane attached to Dura mater
- Subarachnoid Space: contains CSF
- Pia mater: highly vascular, adherent to brain and spinal cord
What is Pachymeninx
dura mater
What is Leptomeninx
arachnoid and pia mater
Describe Cerebral Spinal Fluid
- transudate
- formed by ependymal cells in the choroid plexus
- function is to nourish CNS and act as a cushion
- must be produced and drained at a constant rate
What is the Choroid Plexus?
a cluster or arborizing blood vessels covered by a thin connective tissue and ependymal cells
- site of CSF production
Describe the connective tissue coverings of the nerves
- Endoneurium covers each nerve fiber
- Perineurium covers each fascicle of nerve fibers
- Epineurium covers entire nerve
