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86 Cards in this Set
- Front
- Back
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monitors changes occurring both inside and outside the body
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sensory system
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response, activating effector organs
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motor output
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Interpretation and processing info.
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intergration
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brain and spinal cord make up...
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CNS
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2 subdivisions of the PNS
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Afferent & Efferent Divisions
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Afferent/Sensory
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incoming information to the CNS
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Efferent/Motor
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from CNS --> out
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2 divisions of the Efferent division (of PNS)
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somatic & autonomic
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CNS to skeletal muscle; conscious control
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somatic nervous system
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CNS to smooth muscle; involuntary
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autonomic nervous system
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2 parts of the autonomic nervous system
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sympathetic & parasympathetic
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fight, flight, fright, f*ck
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sympathetic
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rest & digest
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parasympathetic
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sympathetic & parasympathetic together make....
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dynamic antagonism
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the nervous system is comprised of two types of cells:
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neuroglia ("glial") & neurons
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Neuroglia:Neurons
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10:1
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4 types of Neuroglia in the CNS
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astrocytes
microglial cells ependymal cells oligodendrocytes |
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form the Blood-Brain Barrier
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astrocytes
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determine capillary permeability
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astrocytes
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immune system cells; phagocytic
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microglial cells
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form CSF (cerebrospinal fluid) in the CNS
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ependymal cells
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average human has 150-160 mL (1/2 a beer can of this)
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CSF (cerebrospinal fluid)
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insulated covering (myelin sheath) of axon in the CNS
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oligodendrocytes
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2 types of neuroglia in the PNS
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Satellite cells
Schwann cells |
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surround neuron cell bodies in the PNS
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satellite cells
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form myelin sheaths around PNS fibers
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Schwann cells
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gaps between Schwann cells (PNS)
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nodes of ranvier
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the thicker the myelin sheath....
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the faster the information travels
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these love glucose and heavy blood flow (hate ischemia)
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neurons
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structural units of the nervous system
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neurons
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soma, perikaryon AKA
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neuron cell body
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clusters of cell bodies in CNS
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Nuclei
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clusters of cell bodies in PNS
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Ganglia
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main parts of a neuron
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Cell body
Dendrites Axons |
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dendrites convey messages to the cell body by
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Graded Potentials
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how many axons does a neuron have?
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ONE axon (long or short)
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launching area from cell body to axon
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hillock
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generates nerve impulses
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axons
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a long axon is called a...
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nerve fiber
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receives information, carries it into the cell body
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dendrites
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substances transported along axon via cytoskeletan
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anterograde (outside cell body)
retrograde (inside cell body) |
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outer part of Schwann cell (PNS)
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neurilemma
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CNS
myelinated axons (info in transit) |
white matter
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CNS
cell bodies & unmyelinated axons (info processing) |
gray matter
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Classification of FUNCTIONAL Neurons
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afferent
efferent interneuron ("association") |
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afferent neurons are ___ polar
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uni
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efferent neurons are ___ polar
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multi
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multipolar and comprise 90% of neurons in CNS
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interneuron
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dendrytes
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carry graded potentials to cell body
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"excitable" cells
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neurons
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generate action potentials (electrical or nerve impulse)
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neurons
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different types of potentials:
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1- Resting Membrane Potential (RMP)
2- Graded Potentials (dendrites to cell body) 3- Action Potentials (travel along axon) |
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Basic Principles of Electricity
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Voltage
Potential Difference Current Resistance |
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potential energy generated by separate charges
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voltage
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inside cell NEGATIVE
outside cell POSITIVE |
potential difference
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flow of electrons in/out of the neuron
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current
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insulators & conductors
major role of myelin sheath |
resistance
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Ion Channels
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*Chemically-Gated
*Voltage-Gated (K, NA) *Mechanically-Gated |
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BASIS OF NEURON FUNCTION
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Ions moving along chemical and electrical gradients
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Resting Membrane Potential (RMP) in a typical cell is how many mV?
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-70mV
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membrane is polarized
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- on inside (K)
+ on outside (Na) |
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REDUCTION in membrane potential
(inside LESS negative) |
depolarization
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INCREASE in membrane potential
(inside MORE negative) |
hyperpolarization
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graded potentials can initiate
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action potentials
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Action Potential Cycle
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Depolarization
Repolarization Hyperpolarization Resting Membrane Potential <repeat> |
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Na+ rushes into cell body & inside becomes negative
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depolarization
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Inside of cell body becomes negative again
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repolarization
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excessive K+ in cell body
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hyperpolarization
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equilibrium of Na is approx.
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+40mV
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equilibrium of K is approx.
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-84mV
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jumping from node to node in myelinated neurons
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Saltatory Propogation
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regardless of stimulus, all action potentials are the same
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"amplitude is constant"
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no AP possible no matter how strong the stimulus
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refractory period
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2 factors that determine conduction velocity
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axon diameter
degree of myelination |
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conduction velocities-
serves skin, skeletal muscle, joints |
Group A
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conduction velocities-
serves autonomics |
Group B
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conduction velocities-
no myelination acts as pain fibers |
Group C
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How can we use fiber conduction velocity in controlling pain?
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Gating Mechanism
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what forms the myelin sheath in the PNS?
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Schwann cells
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what disrupts RMP during depolarization?
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sodium
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has variable amplitude and fades with distance
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graded potentials
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demyelination of CNS... what disease?
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multiple sclerosis
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structure that maintains and restores RMP
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Na+/K+ Pump
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conscious/unconscious
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AFFERENT
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voluntary/involuntary
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EFFERENT
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these cells line the brain cavity
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ependymal
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