Chapter 7 - Neurons Flashcards
The Nervous System has two main parts:
Central
Peripheral
Central nervous system contains which body parts?
brain and spinal cord
Peripheral nervous system contains which body part?
Nerve tissue outside CNS (central nervous system)
What is a nerve cell?
neuron
Neurons are excitable, which means:
generate and transmit information
What are the 3 types of neurons?
Sensory neuron
Motor neuron
Interneurons
Conduct signal towards CNS (to brain or spinal cord); carry information
sensory neurons
Only in brain and spinal cord, interpret sensory signals and initiate response
Motor neuron
Carry signals from CNS to an effector (muscle or gland)
Interneurons
Structure of a Neuron:
Provides huge surface for receiving signals
dendrites
Structure of a Neuron:
Contains all the normal organelles
cell body
Structure of a Neuron:
Nerve fiber, extension down which a signal travels
axon
Structure of a Neuron:
Transmits signal to other cells
axon endings
Insulates outer layer of axon
Myelin Sheath
Nodes are the _______ of the Myelin Sheath
gaps
How does the Myelin Sheath move fast? Why?
by jumping gaps on neurons outside CNS. Needs to be fast to send signals
• Electrical signal caused by sodium (Na+) and potassium (K+) ions crossing through a neuron’s membrane (entering or leaving cell)
Action Potential
Which elements are used in electrical signals?
sodium and potassium
In electrical charges, there are unequal distributions of _______ and _______
Na+ and K+; sodium and potassium
Within Resting Potential, potassium concentrations are high _______ of cell
inside
Within Resting Potential, sodium concentrations are high _______ of cell
outside
Cell uses _______ for pumps to maintain or reset sodium/potassium balance
energy
Cell is negative inside, positive outside
resting state
Signal causes Na+ gates to open
depolarization
Restoration of resting state
repolarization
In depolarization, interior of cell becomes _______ charged
positively
In repolarization, interior of cell becomes _______ charged
negatively
Action potential travels along axon how?
like a wave
Sodium-potassium pump restores original distribution of ions
Restoration of Ion Distribution
Junction between a neuron and another neuron
Synpase
Chemicals that carry signals between neurons
Neurotransmitters
What is the process that neurotransmitters do?
exocytosis
Any given neuron may have how many excitatory and inhibitory synapses?
thousands
Membrane bound structure that contains something
vesicle
What are the 3 ways neurotransmitters are removed from the synaptic cleft?
Enzymatic removal
Recycled
Diffusion
Neurotransmitter examples:
Serotonin
Norepinephrine
Dopamine
Which element is the first ion flooding into the system?
Sodium
Why must neurotransmitters be removed once used?
They must be removed otherwise they will fire off again
