RUSVM Physio Neuro Part 1 Flashcards
Define Interneurons or associated neurons
found in the brain/spinal cord, connecting motor and sensory neurons
What is Dura Mater?
Outermost meningeal layer, often fused with the inner surface of the skull, thicker protects the CNS
What are the two major subdivisons in the mammalian NS
-Central NS and Peripheral NS
Where are Glial cells located?
CNS = microglial cells, astrocytes, oligodendrocytes, ependymal cells. PNS= Schwann cells
Where does the Myelin sheath originate from and are part of?
Schwann cells in PNS
Oligodendrocytes in the CNS
What is the CNS protected by?
the meninges and the CSF
What does the endoneurium surround
The peripheral nerve fiber
Describe bipolar neurons
- 2 processes (1 axon, 1 dendrite)
- Interneurons - interconnect various neurons within the brain/spinal cord
What is the role of oligodendrocytes
- Provide support to axons of neurons in CNS
- Myelinate most axons >1um in diameter
- The myelin sheath is the reason the brain has white matter
What is the role of the ependymal cells
- Cover the ventricles of the brain, central canal of the CNS and choroid plexus in the 4th ventricle of the medulla oblongata
- Involved in creating CSF
Describe unipolar neurons
- Have a single process that bifurcates to form 2 processes (peripheral and central)
- Sensory neurons (AFFERENT)- send information from receptors in sensory organs toward the brain/spinal cord
What is the CNS composed of
The brain and spinal cord
T/F Loner axons have longer internodes and faster conduction velocities
True
What is Saltatory conduction
The action potential jumps from node to node. The depolarization is much more rapid than in unmyelinated fibers.
What does the Neuroglia or glial cells NOT do
- They do not produce action potentials
- They do not participate directly in synaptic interactions and electrical signaling.
What is the role of Microglial cells?
- The brains immune cells. Act as macrophages- also release NO to prevent viral replication.
- Protect the brain against injury and infection
- Play a role in the developing brain- help destroy synapses that are unnecessary.
T/F Schwann cell cytoplasm forms a ring inside and outside of the sheath
TRUE
What is the Peripheral NS composed by?
Composed by all the neural tissue outside the CNS
Describe a multipolar neuron
- Numerous cell processes (1 axon many dendrites)
- Motor neurons (EFFERENT)- send information from the brain/spinal cord to muscle/glands
- Most prevalent type of neuron
What are the periodic interruptions on the axon?
Nodes of Ranvier
What cells are involved in creating CSF
Ependymal cells
What is the fascicle surrounded by?
the perineurium
What is nerve surrounded by
Epineurium
Where is CSF found within?
Subarachnoid space
Central canal of the spinal cord
Ventricular system of the brain
Define Sensory or afferent neurons
send information from receptors towards the brain/spinal cord
Define Motor or Efferent neurons
Send information away from the brain/spinal cord to muscle/glands (effectors)
How do neuroglia or glial cells play an important role in the NS
- Participate in the production of myelin sheaths of axons
- Modulate the growth of developing or damaged neurons
- Buffer extracellular concentrations of K and NT
- Participate in the formation of contact between neurons (synpases)
- Participate in certain immune responses of the NS
What 3 protective layers is the entire CNS surrounded by
- Pia Mater
- Arachnoid
- Dura Mater
What is the role of Schwann cells
-Provide support to axons of the Peripheral Nervous System
What is the role of astrocytes?
- Numerous long cell processes. 50% of the glial cell population in the CNS.
- Provide structural and metabolic support for neurons.
- Helps elongate axons and dendrites.
- Maintain a neuron’s working environment. Controls the concentration of important ions.
- Modulate how neurons communicate.
What does the PNS do?
Delivers sensory information to the CNS
Carriers motor commands to the peripheral tissues and systems.
What is Pia Mater?
Inner most meningeal layer, laying next to CNS
T/F Depolarization is much slower than in unmyelinated fibers?
False, they are much more rapid.
What is Arachnoid?
Traps CSF, Subarachnoid space
T/F conduction velocity in myelinated fibers is proportional to the diameter
True
