Test 4 Nervous System Flashcards
What neurons are responsible for transmitting conducting Sensory stimuli from Peripheral Nervous System to the Central Nervous System?
Afferent Neurons
What are the different Sensory Neurons?
Somatic Senses
Special Senses
Visceral Senses
What neurons are responsible for transmitting signals from the Central Nervous System to the muscles and glands?
Efferent
What portion of the Neuron contains the nucleus and other cell organelles?
Soma (Cell Body)
What portion of the Neuron receives stimuli or messages via chemoreceptors?
Dendrites
What portion of the Neuron carries nerve impulses away from the soma to axon terminal?
Axon
What portion of the Neuron releases neurotransmitters in synaptic knobs/terminal buttons?
Axon Terminals
How do Neurons communicate with one another?
Via Chemical neurotransmitters via synaptic transmission
What portion of the Neuron is a phospholipid membrane that surrounds, protects, electrically insulates the axon, and is a signal amplifier?
Myelin Sheath
What is the primary phospholipid of the Myelin Sheath of a Neuron?
Galactocerebroside (Sphingolipid, strengthens the sheath)
What produces the Myelin Sheath that surrounds Neurons in the PNS and CNS?
PNS: Schwann Cells
CNS: Oligodendrocytes
What are the gaps in the myelin sheath, where the action potential occurs during conduction along the axon of a Neuron called?
Nodes of Ranvier (Neurofibrillar Nodes)
What is the resting membrane potential a Neuron maintains and how is this accomplished?
-70mV
Via: Adenosine tri-phosphate (ATP) mediated active transport and passive diffusion of ions
What creates the resting membrane potential?
Na+-K+ ATPase Pump
To create the resting membrane potential of -70mV what is being transferred by the Na+-K+ ATPase pump of the cell membrane?
3 Na+ out of the cell
2 K+ intracellularly
What function does the Na+-K+ ATPase pump have after action potential has passed?
Restore resting concentration.
Na+ outside cell
K+ inside cell
What is the mmol concentration of Na+ and K+ Extracellular and Intracellular in the steady-state condition of the cell membrane?
Extracellular: -Na+ = 150mmol/L -K+ = 3-4mmol/L Intracellular: -Na+ = 5-10mmol/L -K+ = 120-135mmol/L
Uncompensated positive charges outside and inside the cell arrange along the inner and outer cell membrane causing what?
only vicinity of cell membrane is charged
What does the concentration gradient favor upon depolarization of the cell membrane?
- Extracellular Diffusion of K+
- Intracellular Diffusion of NA+
Chemical, Mechanical, or electrical stimuli can activate a neuron leading to the generation of what?
Nerve Impulse
At what point will a Neuron generate a Nerve Impulse?
Depolarization exceeds the THRESHOLD level of -55mV
What occurs regarding to ion follow when the threshold level -55mV is reached?
- Activated Gated-Na+ Channels open
- Causing: large influx of Na+ into the cell
The opened Gated-Na+ Channels will drive the depolarization to what level?
+30-35mV (max membrane potential)
The depolarization/electrical signal that propagates down the axon membrane is referred to as?
Action Potential
How is the Neuron’s action potential/depolarization carried from one Neuron to another across the Synaptic Cleft (AKA Synaptic Gap)?
- Axon Terminal: Voltage-gated calcium channels open causing an influx of calcium ions
- Ca^2+ triggers fusion of storage vesicles w/terminal bud membrane
- Releasing a neurotransmitter into synaptic cleft
