Chapter 12: Nervous System Flashcards
2 organ systems that maintain internal coordination
Endocrine and Nervous
Endocrine System
communicates via hormones in the blood
Nervous System
electrical and chemical means to send messages cell to celll
Central nervous system (CNS)
brain and spinal cord
Peripheral nervous system (PNS)
Nerves and ganglia
The PNS is divided into what divisions
sensory and motor
Sensory (afferent) divisions
carries signals from various receptors
Visceral Motor divison (ANS)
Dont have control over these two affectors (Parasympathetic and sympathetic division)
Sympathetic
arouses body for action (fight or flight)
Parasympathetic
calms body (rest and digest)
3 classes of neurons
sensory, interneurons and motor
Neuroglia/Glial cells
Protects neurons, binds them together, provides supportive framework for nervous tissue
Types of glial cells
Ependymal, microglia, astrocytes, schwann cells, satellite cells, oligodendrocytes
Myelin sheath
Spiral layer of insulation around a nerve fiber
Electrical Potential
Difference in concentration of charged particles between one point and another, under the right circumstances can produce a current
Summation
process of adding up post synaptic potentials and responding to their net effect
Temporal Summation
This occurs when a single synapse generates EPSPs so quickly that each is generated before the previous one fades. This allows the EPSPs to add up over time to a threshold voltage that triggers an action potential (fig. 12.26). Temporal summation can occur if even one presynaptic neuron stimulates the postsynaptic neuron at a fast enough rate.
Spatial Summation
This occurs when EPSPs from several synapses add up to threshold at the axon hillock. Any one synapse may generate only a weak signal, but several synapses acting together can bring the hillock to threshold. The presynaptic neurons collaborate to induce the postsynaptic neuron to fire.
Nervous System
Nervous system is the foundation of our conscious experience, personality, and behavior
Excitability (Irritability)
Respond to environmental changes called stimuli
Conductivity
Respond to stimuli by producing electrical signals that are quickly conducted to other cells at distant locations
Secretion
When an electrical signal reaches the end of nerve fiber, the cell secretes a chemical neurotransmitter that influences the next cell
Axonal Transport
two-way passage of proteins, organelles, and other material along an axon
Anterograde transport: movement down the axon away from neurosoma
Retrograde transport: movement up the axon toward the neurosoma
Myelination
production of the myelin sheath
Nerve growth factor (NGF)
protein secreted by a gland, muscle, or glial cells and picked up by the axon terminals of neurons
Action Potential
dramatic change in membrane polarity produced by voltage-gated ion channels
Refractory Period
period of resistance to stimulation
Saltatory Conduction
Myelinated fibers conduct signals with saltatory conduction—signal seems to jump from node to node
Neuromodulators
chemicals secreted by neurons that have long term effects on groups of neurons
Neural Integration
the ability to process, store, and recall information and use it to make decisions
Neural Coding
the way the nervous system converts information into a meaningful pattern of action potentials
Electrical Potential
Difference in concentration of charged particles between one point and another
Current
Flow of charges particles
RMP
Charge difference across plasma membrane (-70 mV)
Action Potential
Dramatic change produced by voltage-gated ion channels in the plasma membrane
Neurotransmitters
Molecules that are synthesized by a neuron, released when a nerve signal reaches an a on terminal or varicosity of the nerve fiber and has an effect on the receiving cells physiology
Immediate memory
Ability to hold it in the mind for a few seconds
Short term memory
Few seconds to a few hours
Working memory
Form of STM that allows you to hold an idea in the mind long enough to carry out an action
Long term memory
Lasts up to a lifetime and is less limited than STM
Explicit LTM/ Declaritive memory
Retention of events and facts that you can put into words, numbers, names, dates etc.
Implicit memory
Memory of things that come reflexively or unconsciously, including emotional memories and procedural memories
Long term depression LTD
Erases long term memories
Memory loss
Immediate and short term memories vanish simply as neural circuits cease to fire
Multipolar neurons
One axon and multiple dendrites. Most common
Bipolar neurons
One axon and one dendrite
Unipolar neurons
Have a single process leading away from the soma
Anaxonic neurons
Multiple dendrites but no axon
universal properties of neurons
excitability, conductivity and secretion
Functional classes of neurons
Sensory (afferent), interneurons and Motor (efferent)
Four types of glial cells
Oligodendrocytes, Ependymal cells, microglia and astrocytes
oligodendrocytes
form myelin sheath in the CNS that speed signal conduction
Ependymal Cells
Line internal cavities of the brain; secret and circulate CSF
Microglia
Macrophages that wander through CNS looking for debris and damage
Multiple Sclerosis
degenerative disorder of myelin sheath, replaced by scar tissue
Tay Sachs
degenerative disorder of myelin sheath, abnormal accumulation of glycolipid GM2
Excitatory Cholinergic Synapse
uses ACh
Inhibitory GABA-ergic synapse
uses y-aminobutyric
Excitatory Adrenergic Synapse
uses norepinephrine (NE)
Neuromodulators
chemicals secreted by neurons that have long term effects on groups of neurons
Neural Integration
the ability to process, store, and recall information and use it to make decisions
Neural Coding
the way the nervous system converts information into a meaningful pattern of action potentials
Alzheimers
Show deficiencies of ACh and NGF, atrophy of gyri shown in autopsy
Parkinsons
Degeneration of dopamine releasing neurons
