10-10b Organization of Peripheral Nervous System Flashcards
What is a neuron?
The fundamental functional unit of the nervous system
What are the major structures of a nerve?
axon
cell body
dendrites: receive info from multiple sources, integrates it, then transmits it through other n. via the axon
What are the major functional regions of a nerve?
Input
Integrative: Integrates all the inputs coming into the n./cell body
Conductive: transmitted to a distant region
Output
What are the different types of neurons/distinguishing characteristics of each?
motor n.: cell body, dendrites, and long axons that innervate the m.
Sensory n.: bipolar neuron, receives info from sensory receptors then transmits to cell body (integrates the info there), then transmits to central n.
separates in the center and sends an axon out on each side
Where is a motor n. located in the peripheral NS?
spinal cord
Where is the cell body for a peripheral sensory neuron?
dorsal root ganglion (outside S.C.)
What is the cell body/soma?
main integrative unit of the neuron supports basic metabolism multiple dendrites (receive input) > integrated in soma > AP sent down axon
What does the nucleus do in the soma?
stores DNA
What does the rough ER have? What is the ER responsible for?
mRNA
responsible for synthesis of lipids and proteins and synthesis of synaptic vesicles that carry the NT to the output region
What do lysosomes do?
digest compounds (glycogen > glucose) part of axoplasmic transport system
What do mitochondria do?
produce ATP
What does the golgi apparatus do?
stores the lipids and proteins that the ER creates
What are microtubules?
Freeways of the neuron that are apart of the axonal transport system
What are the two purposes of axons?
- transmit information to different neurons via AP via ions
- transportation system where NT vesicles (produced in cell body) are transported to the output region and presynaptic terminal (axonal transport system)
(also retrograde axonal transport system: vesicles taken from presynaptic terminal back to the neuron)
physical vesicles transported
How does tetanus enter the neuron?
microbacteria enter the peripheral part of the neuron and ride the retrograde transport system
How is myelin formed in myelinated axons? How do they form the myelin sheath?
Schwann cells
wrap around the axon in concentric circles to form myelin sheath
How is myelin formed in unmyelinated axons?
Schwann cells do not wrap around the n.
What is the function of a Schwann cell?
Protection and insulate the axon
How do neurons transmit information within the neuron and between neurons?
Resting membrane potential, Post synaptic potential, and Action potentials
synaptic mechanisms: convergence and divergence
What is RMP? What is the RMP (+ or -)? What does a pathology of RMP cause?
potential difference in the charges across a membrane
inside: negative at rest; baseline is important
pathology: epilepsy; if not stable, the n. will fire randomly and cause strange brain activity
What are the physical principles behind the neuronal membrane? construction?
ions are separated by the neuronal membrane via its semi-permeable phospholipid bilayer (lipids inside)
partially permeable to some ions and blocks the movement of other ions