Nervous Tissue Flashcards
Controls functions that are under conscious voluntary control with exception of reflex arcs
Somatic NS
Mediates reflex actions called REFLEX ARCS
Neural pathways
Provides sensory and motor innervations to all parts of the body except viscera, smooth and cardiac muscle and glands
Somatic NS
Functional unit of the nervous system
Neuron or Nerve cell
Specialized contacts between neurons that provide for transmission of information from one neuron to the next
Synapses
Selective restriction of blood-borne substances in the CNS
Blood-brain barrier
Neurons that convey impulses from the receptors to the CNS
Sensory
Neurons that convey impulses from the CNS or ganglia to effector cells
Motor
Neurons that form a communicating and integrating network between the sensory and motor neurons
Interneurons or Intercalated neurons
Processes that transmit impulses away from the cell body to a specialized terminal
Axon
Processes that transmit impulses from the periphery toward the cell body
Dendrites
Neurons that have one axon and two or more dendrites
Multipolar
Small molecules that are released at the synapse that affect other neurons as well as muscle cells and glandular epithelium
Neurotransmitters
Neurons that have one axon and one dendrite
Bipolar
Neurons that have one process, the axon, that divides close to the cell body into two long axonal branches
Pseudounipolar
Serves as landmark to distinguish between axons and dendrites in both LM and TEM preparations.
Axon hillock
Receptor processes that receive stimuli from other neurons or from the external environment
Dendrites
Significantly increase the receptor surface area of a neuron
Dendritic trees
Effector processes that transmit stimuli to other neurons or effector cells
Axon
The region of the axon between the apex of the axon hillock and the beginning of the myelin sheath is called
Initial segment
The initial segment is the site at which an _____ is generated in the axon
Action potential
A slowly progressive neurologic disorder caused by the loss of dopamine-secreting cells in the substantia nigra and basal ganglia of the brain
Parkinson’s disease
Is a neurotransmitter responsible for synaptic transmission in the nerve pathways coordinating smooth and focused activity of skeletal muscles
Dopamine
Slowness of movement
Bradykinesia
Inability to initiate movement
Akinesia
Represent accumulation of intermediate neurofilaments in association with proteins alpha-synuclein and ubiquitin
Lewy bodies
Precursor of DA that can cross the blood-brain barrier
L-Dopa
A drug that stimulates release of DA from neurons
Amantidine
