Nervous Tissue Flashcards
Central nervous system
spinal cord, brain
Peripheral Nervous system
cranial, spinal and peripheral nerves conducting impulses
Ganglia
Sensory somatic
sensory input received consciously (eyes, ears, skin, musculoskeletal structures)
Sensory visceral
sensory input not received consciously (internal organs and cardiovascular structures)
Motor somatic
motor output controlled consciously (skeletal muscles)
Motor autonomic
motor output not controlled consciously (heart or gland effectors)
Neuron cells
functional units of PNS and CNS. Process information and generate response to stimuli
Glial cells
support and protect neurons, participate in neural activities, neural activities, and defense of cells in CNS
Three parts of the neuron
Cell body
Dendrites
Axon
Cell body
Large with a large nucleus and well-developed nucleolus
what are nissl substances/ bodies?
large masses of free polyribosomes and RER, indicating a high rate of protein synthesis
dendrites
receive input from other neurons
Axon
carries impulses from cell body and is covered by a myelin sheat
The space between the end of the axon and the cell membrane is the
synaptic cleft
what enables the continuity of of the nerve impulse?
Neurotransmitters
Neurons maintain:
an ionic gradient (electrical potential) across the cell membrane. They can change this gradient in response to stimulus
Neurons conduct
nerve impulse, action potential, or depolarization wave.
The nerve impulses are propagated along the axon as a wave produced by
voltage-gated sodium and potassium channels in the axolemma tat allow diffusion of these ions in the axoplasm
what is the axolemma?
the cell membrane of axon
what is axoplasm
the cytoplasm of axon
communication with another neuron or effector cell occur via
synapse where neurotransmitter is released at the presynaptic membrane and binds receptors on the postsynaptic cell
All neurons consist of
perikaryon (cell body) containing the nucleus
the axon which is a long cytoplasmic extension
one or more shorter processes called dendrites
presynaptic terminals contain
large number of synaptic vesicles with neurotansmitters
neurotransmitters are transported in
vesicles to the presynaptic terminal
Neurotransmitters are released by
exocytosis from the terminal bouton
the transmission of nerve impulses is
unidirectional
synapses convert
an electrical signal from the presynaptic cell into a neurotransmitter that affects the postsynaptic cell
synapses ca be etiher ____ or ______
excitatory or inhibitory
excitatory
depolarizes cell membrane
inhibitory
hyperpolarizes cell membrane
what are local anesthetics
low-molecular-weight molecules that bind to the voltage-gated sodium channels, interfering with sodium ion influx and inhibiting the action potential responsible for nerve impulse
What causes Parkinson’s disease
loss of dopamine-producing neurons
Selective serotonin reuptake inhibitors SSRI
designed to increase levels of serotonin at the postsynaptic membrane by inhibiting the re-uptake at the presynaptic membrane
What is the principal signal reception and processing sites on neurons?
Dendrites
In the CNS most synapses on dendrites occur on
dendritic spines, membrane protrusions along the small dendritic branches
What changes are important in neural plasticity
dendritic spine morphology changes as synaptic connections on neurons are modified
what is neuroplasticity
the ability of neural networks in the brain to change through growth and reorganization
