Nervous System Flashcards
Ganglia
Small collections of cell bodies
Tracts
Bundles of nerve fibers running through the CNS
White matter
Contains dense collections of myelinated fibers (tracts)
Gray matter
Contains mostly unmyelinated fibers and cell bodies
Sensory Input
Uses sensory receptors to monitor changes (stimuli) inside and outside the body, gathered information
Integration
Processes and interprets the sensory input, decides what should be done at each moment
Motor Output
The response/effect caused by integration, activated by activating muscles or glands
Structural Classification subdivisions
Central Nervous System (CNS), Peripheral Nervous system (PNS)
Functional Classification subdivisions
PNS: Sensory division, Motor division
PNS: Sensory Divison
Nerves that convey impulses to the central nervous system from the sensory receptors
PNS: Motor Divison
Carries impulses from the CNS to effector organs, muscles and glands
Somatic Nervous system
Motor subdivision, Allows us to consciously control our skeletal muscles
Autonomic Nervous System
Motor subdivison, Regulates events that are involuntary (activity of smooth muscle, cardiac muscle and glands)
CNS Neuroglia
“Nerve Glue”, include cells that support neurons
Astrocytes
Helps protect neurons from harmful substances that may be in blood
Microglia
Phagocytes that monitor health of nearby neurons, dispose of debris such as dead brain cells and bacteria
Ependymal cells
Line central cavities of the brain and the spinal cord, Participate in the production of cerebrospinal fluid
Oligodendrocytes
Wraps flat extensions tightly around CNS nerve fibers producing Myelin Sheath
Schwann cells
From myelin sheath around nerve fibers in the PNS
Satellite cells
Acts as protective cushioning cells for peripheral neuron cell bodies
Synaptic Cleft
Seperates axon terminal from next neuron/targetted by tiny gap
Synapse
Functional junction where an impulse is transmitted from one neuron to another
Neurilemma
Part of the schwann cell external to the myelin sheath
Neuron Functional Classification: Sensory Neurons
Resting Potential
The plasma of a resting/inactive neuron is polarized, less positive ions sitting on inner face than outer face of plasma membrane
Depolarization
Stimulus causes sodium channels to open, sodium ions flood the cell
Graded Potential
a local electrical situation, locally inside is more positive and outside less positive
Action Potential
The impulse signal initiated by graded potential and sodium influx transmitted
Repolarization
Membrane becomes impermeable to sodium ions, potassium ions rapidly diffuse in and out of neuron into interstitial fluid, outflow of positive ions from cell restores electrical conditions of membrane to the polarized/resting state
Hyperpolarization
A change in a cell’s membrane potential that makes it more negative. It is the opposite of a depolarization
Meninges
