Neurons, Synapses, and Signaling Flashcards
A nervous system _____
includes sensory information, integrating center, and effectors
The “information receiving” section of a neuron is its _____
dendrites
The nucleus and most of the organelles in a neuron are located in the
cell body
The point of connection between two communicating neurons is called
the synapse
Ions move in the direction opposite to that favored by the chemical concentration gradient when _____
they are pumped by proteins that require ATP hydrolysis and when the electrical charge gradient repulses or attracts them
The operation of the sodium-potassium “pump” moves
sodium ions out of the cell and potassium ions into the cell
Two fundamental concepts about the ion channels of a “resting” neuron are that the channels
open and close depending on stimuli, and are specific as to which ion can move through them
The “threshold” potential of a membrane
is the minimum depolarization needed to operate the voltage-grated sodium and potassium channels
After the depolarization phase of an action potential, the resting potential is restored by
the opening of voltage-grated potassium channels and closing of sodium channels
Immediately after an action potential passes along an axon, it is not possible to generate a second action potential; thus, we state that the membrane is briefly
refractory period
Nervous System and Neurons
- NS works by both electrical and chemical signals
- chemical=neurotransmitters
- NS controls the endocrine system and is good at controlling movement
- neurons send signals while neuroglia are supporter cells
Functions of the Nervous System
- all overlapping
- Sensory input=monitoring changes both inside and outside of the body; ex: temperature, pressure
- Integration=processing and interpreting inputs, understand stimulus
- Motor Output=responding to a stimulus and stimulates muscles and/or glands
Divisions of the Nervous System
- Central NS=integration, brain and spinal cord
- Peripheral NS=sensory input, motor output, everything outside of the CNS
Functional Classes of Neurons
- Sensory (Afferent)=convey impulses toward the CNS
- Integration (Interneurons)=analyze and interpret data
- Motor (Efferent)=transmits impulses away from the CNS
Anatomy of a Neuron
- soma=cell body, makes decisions on how strong the electrical signal is from the dendrites, houses most organelles
- Dendrites=carry information toward the soma, connected to soma
- axon=carries information away from the soma, each neuron has one
- terminal branches=one end of axon, one or many
- synapse=gap, releases neurotransmitters to communicate with target cells, prevents neurons from being electrically bound
