Quiz 1 Flashcards
Central Nervous System
Made up of Brain and Spinal Cord
Brain
Body’s command system
coordinates functions
initiates reactions
Spinal Cord
quick reflexes
Peripheral Nervous system
all parts of nervous system not in central nervous system
Somatic
communicates with body’s sense organs and VOLUNTARY muscles
Sensory (afferent) –> brain
Motor (efferent)–> skeletal muscles to brain
Afferent Neurons
Sensory neurons
carry messages from body’s sense receptors (eyes, ears, nose, etc) to CNS
.9% of all neurons
Efferent Neurons
Motor neurons
carry signals from CNS to muscles and glands
account for 9% of neurons
Autonomic
communicates with internal organs and glands
Sympathetic
arousal of “fight or flight”
Parasympathetic
calming
returns body to homeostasis (balanced state)
Interneurons
Swift relfexes form all neural wiring within CNS 2 axons instead of 1 and dendrite 1 axon --> spinal cord 1 axon--> Skin or muscle
Dendrites
Receive signals, pass it through neuron
picks up neural transmissions at end and flows throughout neuron
Soma (cell body)
Contains nucleus and other structuress
Axon
Passes messages AWAY FROM cell body through its branches to other neurons
Myelin Sheath
fatty tissue layered segmentally encasing and protecting axons of some neurons
helps speed impulses
Axon terminals
form junctions with other nerve cells, sending signals
Vesicles
Contain neurotransmitters
Neurotransmitters
Chemical messengers
Reuptake
reabsorption of neurotransmitter by the pre- synaptic neuron AFTER it has performed its function of transmitting a neural impulse
Action potential
Neural impulse: brief electrical charge travels down axon, generated by movement of positively charged atoms in and out of axon’s membrane
Resting potential
wen neuron doesn’t send signal = at rest
when at rest, neuron is negative relative to outside
Threshold
Level of stimulation required to trigger a neural impulse
when reaches threshold, it’ll fire (action potential)
Depolarization
an exicitory stimulas causes sodium gates to open
positively charged sodium ions flow into cell
moves from -70 to 0 mv
Repolarization
A rush of positively charged K flow out of the cell, moving the membrane closer to 0mv
