Intro to Nervous System Flashcards
Sensory Input
Monitoring stimuli occurring inside and outside of the body
Integration
Processing of sensory input and formulation of motor commands
Motor Output
Response to stimuli by activating effector organs
Central Nervous System (CNS)
Brain and Spinal Cord
Peripheral Nervous System (PNS)
All nervous tissue outside CNS
Reflexes
Predictable rapid response to a stimulus
Receptor of a reflex
Detects a stimulus
Afferent (Sensory) Neuron of a reflex
Relays information to CNS
Control Center of a reflex
Region of the CNS that processes sensory information and sends motor commands
Efferent (Motor) Neuron of a reflex
Carries motor commands away from CNS to the effector
Effector of a reflex
Muscle or gland that responds to motor commands by producing the response
Afferent Fibers (Sensory) Division of PNS
Carry info from receptors to the CNS
Somatic Afferent Fibers of PNS
Carry impulses from skin, skeletal muscles and joints
Visceral Afferent Fibers of PNS
Carries impulses from organs within ventral body cavities
Special Sensory Afferent Fibers
Carries impulses from nose, eye, tongue, and ear
Efferent (Motor) Division
Motor neurons carry commands away from CNS to effectors
Somatic Efferent Fibers
Control voluntary skeletal muscle contraction
Autonomic Efferent Fibers
Control involuntary cardiac muscles, smooth muscles and glands
Sympathetic Division
Travels through thoracic and lumbar spinal nerves and produces the flight or fight responses to mobilize energy reserves and prepare for activity to deal with stress
Parasympathetic Division
Travels through cranial nerves and sacral spine nerve and produces the rest and digest maintenance responses to store and conserve energy
Soma of a neuron
Cell body or perikaryon; contains nucleus and organelles
Dendrite of a neuron
Branching extensions that contain receptors to detect neurotransmitters from other neurons
Axon Hillack of neuron
Where cell body tapers into the axon, site where the action potential originates
Axon of neuron
Single long process, transmits action potential away from soma
Axolemma of neuron
Plasma membrane of an axon
Myelin sheath of neuron
Insulation formed by glial cells wrapping around the axon
Nodes of Ranvier
Gaps in the myelin sheath
Internodes
Segments of myelin
Axon Terminals of neuron
Enlarged distal ends of an axon that contains secretory vesicles filled with neurotransmitters (synaptic vesicles)
Sensory (Afferent) Neurons
Carry sensory information from sensory receptors to CNS
Interneurons
Between sensory and motor neurons, only in CNS
Motor (Efferent) Neurons
Carry commands from CNS to effector organs
Multipolar Neurons
Multiple processes branching off the cell body, numerous dendrites and one axon
Unipolar Neurons
Appear to have one extension off the cell body. This extension branches forming a long axon with dendrites on one end and axon terminals on the opposite end.
Most Sensory Neurons of the PNS
Bipolar Neurons
Two Extensions from cell body, one dendrite & one axon. Found in special sense organs.
Astrocyte Cells
Star Shaped, processes cling to neurons and capillaries >Provide structural support >Maintain blood brain barrier >Adjusts interstitial environment >Guides neuron development
Olingoclendrocyte Cells
Wrap cytoplasmic processes around the axons and neurons
>Forms a white fatty insulation material called a myelin sheath
Microglial
Oval Cells with long thorny processes
>Remove cellular debris and pathogens
Epedymal
Collated cells, line chambers filled with cerebrospinal fluid
>Monitor and maintain the composition of CSF
>Assist in the circulation of CSF
Schwann Cells
Surrounds and protects axons in the PNS
>Forms myelin sheath around some axons of PNS
Neurilemma
Outer layer that contains Schwann cell cytoplasm
Satellite Cells
Surround cell bodies of neurons and isolates cell body and regulates exchange of nutrients and waste
Membrane Potential
Separation of charge across the plasma membrane measured in volts
Resting Membrane Potential
Membrane potential at rest when the cell is not receiving information in the form of a graded potential or sending out information as an action potential. Resting potential is typically around -70mV
Depolarization
The membrane potential becomes less negative
Graded potential
A localized change in membrane potential that is short lived and dissipates as it travels
Action Potential
Electrical impulse producing a brief reversal of the membrane potential that travels down the entire length of the axon from the axon hillock to the axon terminals
Synapse
Junction between two neurons or a neuron and muscles, glands or cells
Presynaptic Neuron
Transmits impulse towards the synapse
Axon terminals of the presynaptic neuron
Release neurotransmitters
Synaptic Cleft
Fluid Filled Space where neurotransmitters are released
Post Synaptic Cells (neuron, muscle, gland, etc.)
Receives information from the presynaptic neurons
