Nervous system divisions
Divisions of the central nervous system
What is the brain and spinal cord?
List the three properties of neurons
1. excitability
2. conductivity
3. secretory
An action potential is...
What is a voltage change that must reach threshold?
Fast anterograde transport is...
What is...
- away from cell body
- organelles, vesicles, enzymes
Peripheral nervous system divides into...
What is the motor and sensory divisions?
Excitability describes
What are neurons that respond to internal/external stimuli by altering voltage across the membrane?
The steps of an action potential are...
What is...
1. Voltage at resting membrane potential is -70 mV
2. Sodium travels into the cell through sodium channel and voltage reaches threshold
3. Mass influx of sodium into the cell increases voltage = depolarization
4. Mass efflux of potassium channels decreases voltage = repolarization
5. Mass efflux of potassium overshoots voltage of resting membrane potential = hyperpolarization
Electrical synapses are...
What are...
- gap junctions
- intercellular protein channels
- brain heart, embryo
Fast retrograde transport is...
What is...
- to cell body
- recycled materials and pathogens
The sensory and motor divisions of the peripheral nervous system (PNS) both separately divide into...
What are the visceral sensory and somatic sensory divisions?
Conductivity describes
What are neurons that produce traveling electrical signals?
Energy usage for nerve cells
What is glucose and lactate?
Chemical synapses are...
- cholinergic (ACh): excitatory
- GABA-ergic (GABA): inhibitory
- adrenergic (NE): excitatory
Regeneration of Schwann cell is...
What is...
- a process that occurs only if soma (cell body cytoplasm) and neurolemma tube (outer layer of Schwann cell) remains intact
What do the visceral motor part of the peripheral nervous system divide into?
What is the enteric division (ENS), sympathetic division (SNS), and parasympathetic division (PSNS)?
Secretory describes
What are neurons that secrete chemical neurotransmitters in response to signal?
Nerve cells cannot use two things for ATP production because...
What is fat or protein because of a nerve cell's lack of enzymes?
The differences between:
1. excitatory cholinergic synapse
2. inhibitory GABA-ergic synapse
3. excitatory adrenergic synapse
What is...
1. AP --> calcium influx and excitatory post synaptic potential when threshold reached
2. AP --> GABA release and inhibitory post synaptic potential (IPSP)
3. AP --> NE release and G-protein binds adenylate cyclase (AC) --> activates cAMP, which causes multiple effects, including opening of ligand-gated sodium channels
Process of Schwann cell regeneration
1. Stranded end of axon and myelin sheath degenerate, ER breaks up, some Schwann cells die
2. Macrophages remove debris, Schwann cells reorganize
3. Axon resprouts, Schwann cells regenerate tube and produce NGF
4. Single enlarging axon filament, new myelin sheath forms
A cell found in the PNS with 2 characteristics
What are Schwann cells that are myelinated and unmyelinated?
Distinguish the types of neurons
What is...
1. unipolar
2. bipolar
3. multipolar
Two stages of the refractory period
1. absolute: when sodium channels open, further stimuli will not generate new ATP
2. relative: sodium channels closed, potassium channels open, entering hyperpolarization (voltage mostly recovered); stimulus may generate another AP before resting membrane potential is reached/resumed
Types of summation post synaptic potentials
1. temporal summation
- intense stimulation from 1 presynaptic neuron
2. spatial summation
- simultaneous stimulation by several presynaptic neurons, less frequent stimuli through each neuron required for effect
Plasticity is...
What is...
- the ability to form and retain synaptic connections
- dependent on strength of stimulus and repeated stimulation
- and increase or decrease transmitter and/or receptor number to alter strength