Lesson 2 - Nervous Tissues and Neurophysiology Flashcards
neurons
nerve cells that function to transmit electrical impulses
neuroglia
cells that support the neurons
structures in a neuron: soma
the neuron’s cell body
ganglion
a cluster of cell bodies in the PNS
nucleus
a cluster of cell bodies in the CNS
structures in a neuron: axon hillock
tapered structure between the some and axon that is important for producing the action potential
structures in a neuron: dendrites
processes that conduct electrical impulses towards the soma, usually receives a signal from another cell
structures in a neuron: axon
process that conduct electrical impulses away from the soma
tracts
bundles of axons in the CNS
nerves
bundles of axons in the PNS
structures in a neuron: axon/synaptic terminal
found at the end of an axon
structures in a neuron: synaptic cleft
gap found between the axon terminal of one neuron and the target cell
oligodendrocytes
neuroglia that produces myelin in the CNS
Schwann cells
neuroglia that produces myelin in the PNS
neuroglia are important to neuron function, they can: (2)
- produce myelin to insulate a neuron’s axon
- form nodes of Ranvier found between myelinated sections of the axon, and these nodes help propagate and increase action potential velocity
nerve cells are able to propagate an electrical impulse because: (2)
- can change their membrane potential
- membrane potential is maintained by Na+/K+ pump
the action potential is generated at the _____ _____ and travels down the _____
axon hillock, axon
the Na+/K+ pump moves ___ Na+ ions _____ of the cell in exchange for ___ K+ ions _____ of the cell causing a net -1 charge inside
3, outside, 2, inside
an action potential is formed at the axon hillock when:
an excitatory stimulus reaches the axon hillock
what does an excitatory stimulus at the axon hillock cause? (5)
- an influx of Na+ ions into the neuron which depolarizes the membrane in that area
- when it reaches threshold, more Na+ enters the cell in that area
- further membrane depolarization occurs so the charge inside becomes positive
- Na+ influx stops around ~+30mV, then K+ ions starts leaving the cell to depolarize it
- once the cell is repolarized, the K+ ions stop leaving and the resting potential is restored
absolute refractory period
immediately follows an action potential, where further stimulation cannot generate another AP
relative refractory period
follows the absolute refractory period, when a strong stimulus can generate another AP
Label A-D
A: neurofibril
B: nucleus
C: dendrites
D: chromatophilic substance
Label A-C
A: dendrites (receptive regions)
B: cell body (biosynthetic center/receptive region
C: nucleus
Label D-F
D: chromatophilic substance (rough ER)
E: axon hillock
F: axon (impulse generating/conduction region)
Label G-J
G: Schwann cell
H: node of Ranvier
I: terminal branches
J: axon terminals
Label A-C
A: presynaptic neuron
B: direction of action potential
C: mitochondrion
Label D-F
D: synaptic cleft
E: synaptic vesicles
F: axon terminal
Label A-C
A: axon hillock
B: cell body
C: area of polarity reversal/ node of Ranvier
Label D and E
D: myelin sheath
E: distal axon
Label A-C
A: absolute refractory period
B: relative refractory period
C: depolarization
Label D-F
D: action potential
E: repolarization
F: hyperpolarization
Label G and H
G; threshold
H: resting membrane potential
