Nervous Tissue Flashcards
Function of the nervous system
Allows rapid communication between widely spaced parts of the body by the action of specialised cells called neurones which gather and process information and generate a response
Functional cell type of the nervous system
Nerve cell or neurone
Neurones
Receive information and transmit electrical impulses to another neurone or effector cell
Glial cell types
Astrocytes, oligodendrocytes, microglia and ependymal cells
Astrocytes
Many numerous processes
Support, maintaining the blood-brain barrier and environmental homeostasis
Oligodendrocytes
Produce myelin in the CNS (NOT PNS)
Microglia
Similar lineage to macrophages
Immune monitoring and antigen presentation
Ependymal cells
Cuboidal/columnar epithelium that lines the cavities in the CNS such as the ventricle
Typically cillliated
A group of neurones living outside the CNS
Ganglion
Characteristics of neurones
Cell body contains nucleus and most of cell organelles
Long process - axon - transmits data from the neurone to other cells
Numerous short processes - dendrites - increase surface area avalible for connections
Specialised junctions - synapses - between axon and other cells to allow communication
3 groups of neurones
Multipolar, bipolar and psuedopolar
Axon arises from a swelling
Axon hillock
Nerve cell body
Abundant RER, free polyribosomes and Golgi apparatus in the body but not in the axon
Axonal transport
Energy consuming mechanism to move material up and down the axon
How does axonal transport work
Uses molecular motors - kinesin- which use microtubules as a railway track to haul attached organelles and vesicles
Types of axonal transport
Fast axonal transport and slow axonal transport
PNS consists of
Nerves and ganglia and includes elements of the somatic and autonomic nervous systems
Ganglia are composed of
Neurone cell bodies, support cells, axons and loose fibrocollagenous tissue
What are the support cells of the PNS
Satellite cells and schwann cells
What are the two types of nerve ganglia
Dorsal root ganglia and autonomic ganglia
Peripheral nerve is composed of
Axons, schwann cells, fibroblasts and blood vessels
Connective tissue of peripheral nerve
Epineurium - surrounds the whole nerve
Perineurium - surrounds a fascicle
Endoneurium - surrounds individual nerve fibres
Where are unmyelinated axons found
In the clefts in the cytoplasm of schwann cells
What is the myelin sheath formed by in the PNS
Schwann cells
Each schwann cells creates myelin for
A single axon
What produces myelin in the CNS
Oligodendrocytes
Oligodendrocytes makes myelin sheath for
Many axons
In there connective tissue in the CNS
No
What are the spaces in the myelin sheaths called
Nodes of Ranvier
What does the nodes of Ravier allow
For the action potential to jump along the axon increasing the speed of conduction
Grey matter
Huge number of neurones, cell processes, synapses and support cells
White matter
Axons and their support cells
Neuropil
A mat of neuronal and glial cell processes that occupies much of the grey matter
Synapses
Come in many forms
Vesicles in the end contain neurotransmitters that are released in response to an action potential
