Organisation Of The Nervous System Flashcards
What are the primary divisions of the nervous system
Central nervous system
Peripheral nervous system
What structures does the CNS consist of?
Brain and spinal cord
What structure is present in the PNS that is not present in the CNS?
Ganglia
What are ganglia?
Collections of nerve cell bodies outside the CNS
What are the two main divisions of the PNS? (Plus one extra)
Somatic
Autonomic
(Nerves of special sensation)
What are the two cell types of neural tissue?
Neurons
Neuroglia
What are the general functions of neuroglia?
Support neurons
Regulate interstitial fluid
Bring nutrients
What do neurons do?
Transmit electrical impulses along their cell membranes
What are the three main features of a neuron?
Cell body/soma
Dendrites
Axon
Where are most of the organelles in a neuron?
Cell body/soma
What are neuroglia?
Non-nervous support cells
What neuroglia are present in the CNS?
Astrocytes
Microglia
Oilgodendrocytes
Ependymal
What neuroglia are present in the PNS?
Satellite cells
Schwann cells
What is the largest and most numerous neuroglial cell in the CNS?
Astrocyte
What are the processes of astrocytes in contact with?
Dendritic tree
Soma
Walls of capillaries
Myelinated axons
What are the functions of astrocytes? (5)
Maintain blood-brain barrier
Structural strength (microfilaments)
Stabilise structures after injury (produce scar tissue)
Direct neural growth during development
Control interstitial environment
What is the function of oligodendrocytes?
Myelination of axons
What do microglia look like?
Small, slender cells with many branched processes
What is the function of microglia?
(Similar to macrophages)
Phagocytosis
What percentage of glial cells are microglia?
5%
Where are ependymal cells found?
Lining chambers/passageways of CNS containing cerebrospinal fluid
What is the main difference between ependymal cells and epithelial cells?
Ependymal cells have processes in contact with other (glial) cells
What is the function of ependymal cells?
Assist production and circulation of cerebrospinal fluid
May also monitor the composition of cerebrospinal fluid
Where are satellite cells found?
Lining peripheral NS ganglia
What do satellite cells do?
Regulate oxygen, carbon dioxide, nutrient and neurotransmitter levels around neurons in ganglia
What are the functions of a Schwann cell?
Support axons (enclose 10-20 axons together)
Myelination of axons (up to 1mm on a single axon)
What is the main difference between oligodendrocytes and Schwann cells?
Oligodendrocytes can myelinate multiple axons/sections on a single axon
Schwann cells can myelinate only one section on one axon
Where are the CNS structures?
Brain = cranial cavity
Spinal cord = runs through central canal of vertebrae/vertebral foramen