Fundamentals of the nervous system Flashcards
What are parts of the body and functions are in CNS and PNS
CNS
- brain and spinal cord
- Integration and control centre
PNS
- Cranial nerves & spinal nerves
- Communication between CNS & rest of body
What are the 2 principal cell types in the nervous system
Neurons: Excitable cells that transmit electrical signals
- Mass is far greater
Neuroglia: supporting cells (6 types)
- # is greater
What cells are in the CNS & PNS
CNS
- Astrocytes
- Microglia
- Ependymal Cells
- Oligodendrocytes
PNS
- Satellite cells
- Schwann cells
What are astrocytes (star-shaped)
- guide the migration of neurons & formation of synapses
- Tight junctions and basal lamina of the cerebral endothelial cells (cells line blood cells) play an important role in blood brain barrier
What are microglia
- Migrate toward injured neurons
- Phagocytize microorganisms & neuronal debris
What are ependymal cells
- ciliated cells that circulate CSF
- Produce CSF
What are oligodendrocytes
Forms myelins that gives impermeable membranes to axons
What are satellite cells (PNS)
- Control microenvironment around cell body
- Similar to astrocytes in CNS
What are schwann cells (PNS)
Most form myelin sheaths
What is the function of myelin sheaths
- Protect and electrically insulate axon
- Increase speed of nerve impulse
What is the neurilemma? which nervous system is it in?
Peripheral bulge of schwann cells in PNS
What are Nodes of Ranvier?
What effect does it have?
Gaps between the myelin sheaths
- Make AP go faster, also increasing diameter
Where are the voltage gated channels in a neuron
In the axon NOT cell body
What are clusters of cell bodies called in CNS and PNS? and processes in each?
CNS: nuclei; tracts
PNS: ganglia; nerves
What is the function of dendrites?
Receive input as graded potentials (short distance signals)
Where can graded potential be found? action potential?
GP: cell body + dendrites
AP: axon
What is the role of telodendria?
Synapses with synaptic terminals
What are the functions of axons? Name and explain the 2 directions in trafficking.
Anterograde: away from cell body
- Kinesin motor
- Mitochondria, enzymes
Retrograde: toward cell body
- dynein-dyactin motor
- viruses, toxins
Which type of neurons do not generate AP and are unmyelinated
Bipolar neurons
Which type of cell is mainly found in PNS
unipolar, function as sensory neurons
What are the functional classifications of neurons
SENSORY (afferent): transmit impulses from sensory towards CNS
MOTOR (efferent): carry impulses from CNS to effectors
What is Ohms law equation
Current = voltage/resistance