Diploma Prep: Nervous System Flashcards
What are the three basic structures of the nervous system?
Receptors, nerve cells, effectors
What are the five steps involved in a reflex arc?
stimulus, sensory receptor, sense neuron, interneuron, motor neuron, effector (gland / muscle)
When a neuron is polarized, where is sodium / potassium?
sodium outside, potassium inside
What is different between neurons int eh CNS and PNS?
neurons in the PNS have a myelinated sheath and Sshwann Cells
What is a myelinated sheath?
outer coating on the axon of a neuron which allows a signal to travel faster
What are Schwann cells?
Cells which help in the regeneration of damaged neurons
What are the steps of depolarization in an action potential?
- Depolarization
- Repolarization
- Refractory Period / Hyperpolarization
What happens in the depolarization period of an action potential?
Na+ rushes into axon, +40 mV
What happens in the repolarization period of an action potential?
K+ rushes out of axon, -70mV
What happens in the repolarization period of an action potential?
Na+ / K+ pump restores concentration gradient, no new action potential can occur
What direction (on the neuron) does an action potential go?
dendrite to axon
What are the main components of a neuron?
dendrites, nucleus, axon, myelinated sheath, axon terminal, synapse
What is the threshold level?
how much stimulus is required to create an action potential
What is the all - or - nothing response?
size of action potential does not change, regardless of the size of the stimulus
How is strength of a stimulus measured?
high frequency, many neurons
How many different types of neurotransmitters can be released by a neuron?
one
What are the two neurons in a transmission called?
presynaptic neuron and postsynaptic neuron
What is a synapse?
Space between an axon terminal of the presynaptic neuron and the dendrites of the post synaptic neuron
What are the steps of a synapse?
- Ca2+ gate opens
- Ca2+ rushes into neuron
- Ca2+ triggers vessicles containing neurotransmitters to move to the presynaptic membrane
- Neurotransmitters diffuse across the synaptic cleft and bind the postsynaptic cleft
- Excitatory neurotransmitters create an action potential, inhibitory transmitters open K+ or Cl- gate to hyperpolarize
What happens to dopamine after it lands on the post-synaptic cleft?
reabsorbed by vesicles in the presynaptic neuron
What happens to acetylcholine after it lands on the post-synaptic cleft?
It is broken down by acetylcholinesterase and reabsorbed into the presynaptic neuron
What is ACh used for as a neurotransmitter?
neuromusclar junctions, parasympathetic neurons
What is Epinepherine/norepinephere used for as a neurotransmitter?
concentration