Nervous system Flashcards
(83 cards)
The nervous system
responsible for controlling most body functions, enabling organisms to receive and respond to stimuli from their external and internal environments.
Which is faster in relaying signals to the brain, the endocrine or the nervous system?
the nervous system. 100m/s in some cases
neurons
specialized nervous tissue that convert stimuli into electrochemical signals.
neuroglia
cells that support and protect the neurons
Organs of the nervous system
brain, spinal cord, eye, ear, etc.
What are the two divisions of the nervous system?
CNS, PNS
What are the functional units of the nervous system?
neurons
What are neurons composed of?
dendrites, cell body, axon
dendrites
cytoplasmic extensions that receive information and transmit it toward the cell body
cell body (soma)
contains the nucleus and controls the metabolic activity of the neuron.
axon
long cellular process that transmits impulses or action potentials away from the cell body. sheathed with myelin.
Myelin sheath
prevents leakage of signal from the axon and allows for faster conduction of impulses
Nodes of ranvier
gaps between the segments of myelin where the action potential actually propagates through saltatory (hopping) conduction.
Oligodendrocytes
Glial cells that protect the myelin sheath in the CNS. provide structural framework for the CNS
Schwann Cells
Glial cells that protect the myelin sheath in the PNS. Aid in the myelination of some peripheral axons
synaptic terminals
swellings in the axon ends. realease neurotransmitter via this into the synapse (synaptic cleft).
Major cells of the CNS
Astrocytes, Oligodendrocytes, Microglia, Ependymal Cells.
Major cells of the PNS
Satellite cells and Schwann Cells
Astrocytes
CNS. Maintain the integrity of the blood-brain barrier, regulate nutrient and dissolved gas concentrations, and absorb and recycle neurotransmitters
Microglia
CNS. remove cellular debris and pathogens
Ependymal Cells
CNS. Line the brain ventricles and aid in the production, circulation, and monitoring of CSF
Satellite Cells
PNS. Surround the neuron cell bodies in the ganglia
Polarized neurons
Neurons are polarized even at rest because of unequal distribution of ions between the inside and outside of the cell.
resting potential
the potential difference at rest between the extracellular space and the intracellular space. -70mV. inside of the neuron is more negative.