Lecture 3 Flashcards
What are the principle cells of the CNS?
Neurons
How do neurons receive information?
Synapses
What are multipolar with many dendrites and one axons?
Neurons
What are a group of neurons (cell bodies) found outside the CNS called?
Ganglia
What is a cell body also known as?
Soma
What contains the nucleus and most of the cell organelles?
Cell body
What is the long process of a neurone called?
Axon
What is responsible for transmitting data from the neurone to other cells?
Axon
What are the short branched processes of a neurone?
Dendrite
What increases the surface area available for connections from axons of other neurons?
Dendrites
What is between axon and other cells to allow communication?
Synapses
Where does the axon arise from?
A swelling in the soma called the axon hillock
Where do action potential arise?
Axon hillock
What does the axon hillock lead to?
Initial segment of the axon
What are the three types of neurons?
Multipolar, bipolar and pseudounipolar
Describe the multipolar neurones?
Many dendrites and one axon
Describe the bipolar neurons?
One dendrite and one axon
Describe the pseudounipolar neurons?
Short process give rise to axon in both directions
What is axonal transport?
Energy consuming mechanism to move material up and down the axon
What helps axonal transport t work?
Kinesin
What is the fast axonal transport called?
Anterograde transport
What is the middle axon transport called?
Retrograde transport
What is the region containing neuronal and glial cell processes containing myriad synaptic contacts?
Neuropil
What do the vesicles at the end of axons contain?
Neurotransmitters
What is often called a terminal bouton?
Presynaptic axon terminal
What are the four types of glial cells?
Astrocytes, oligodendrocytes, ependymal cells and microglia
What are the roles of astrocytes?
Provide some physical support for the tissue by providing a scaffolding for other cells.
They surround synapses containing a neurotransmitter that held terminate the effect of the transmitter
Help maintain the extracellular environment
Participate in the formation of the blood-brain barrier
What are the two forms of astrocytes?
Fibrous astrocyte and protoplasmic astrocyte
What astrocyte is most common in white matter?
Fibrous astrocyte
What astrocyte has numerous short branching processes?
Protoplasmic astrocytes
What astrocyte is found in grey matter?
Protoplasmic astrocytes
Since astrocytes end in flattened processes they are called?
Endfeet
The astrocyte end feet do not have tight junctions therefore?
They do not form the actual blood-brain barrier but induce capillary endothelium to form tight junctions
What is the covering to the CNS below the pia and ependymal lining of ventricles?
Glia limitans
What produces myelin in the CNS?
Oligodendrocytes
In the CNS, one oligodendrocyte produces?
Several internodes of myelin
In the PNS, what produces myelin?
Schwann cells
What cells have a similar lineage to macrophages?
Microglia cells
What acts as an antigen presenting cell?
Microglia
What are the smallest glial cells?
Microglia
What are the second population of immune cells called?
Perivascular macrophages
Where are perivascular macrophages found?
Around blood vessels
What are cuboidal/columnar epithelium-like cells that line the ventricles?
Ependymal cells
What are ependymal cells called?
Ependymocytes
Why do ependymocytes lack tight junctions?
To allow free exchange between the CSF and the CNS parenchyma
What fills the ventricles?
CSF
What do the ependymal cells line?
Ventricles and central canal
What are tanycytes?
Subset of ependymocytes
Where are tanycytes found?
Lining 3rd ventricle
What cells monitor hormone levels in the CSF?
Tanycytes
The PNS consists of?
Nerves and ganglia
What includes both the somatic and autonomic nervous system?
PNS
What are neuronal relay centres in the PNS?
Ganglia
What does a ganglia comprise of?
Neuron cell body, support cells, axons, loose connective tissue
What are the support cells in PNS ganglia?
Satellite cells and Schwann cells
What cells surround the neuronal cell body?
Satellite cells and schwann cells
What are the two types of ganglia?
Dorsal root ganglia and autonomic ganglia
What is a collection of axons linked together by support tissue?
Nerve
Another word for motor?
Efferent
Another word for sensory?
Afferent
A peripheral nerve is composed of?
Axons, Schwann cells, fibroblasts and blood vessels
Bundles of axons are referred to as?
Fascicle
What are the connective tissue sheaths of a nerve?
Epineurium, Perineurium and Endoneurium
What sheath surround the whole nerve?
Epineurium
What sheath surrounds a fascicle?
Perineurium
What sheath surrounds fibres within a fascicle?
Endoneurium
What are the schwann cell-unmyleinated axon groups called?
Remak bundles
Each schwann cell makes a myelin sheath around?
A single axon
Oligodendrocytes form myelin sheaths and each one makes myelin around?
Many axons
What are the gaps in the myelin sheaths called?
Nodes of Ranvier
In motor neurons, the axons end in?
Neuromuscular junctions on voluntary muscle (e.g. smooth muscle/glands)
Where are Ruffini endings found?
Glabrous skin
Where is the Pacinian corpuscle found?
Deep in the dermis
Where is Meissner’s corpuscles found?
Dermal papillae
What does the neuromuscular junction consist of?
Presynaptic terminal and motor end plate
What are the two types of cortex?
Allocortex and neocortex
What is the allocortex subdivided into?
Archicortex and paleocortex
What part of the cortex is found in the hippocampus?
Archiocortex
What part of the cortex is found in the olfactory cortex?
Paleocortex
What are the layers of the cortex?
Molecular layer, External granular layer, External pyramidal layer, Internal granular layer, Internal pyramidal layer and multiform layer
The cerebellar context has how many layers?
three
What matter is found in the deepest layer of the cortex?
White matter
