FLG 327
ESSENTIAL NEUROPHYSIOLOGICAL CONCEPTS
CHANGES IN MEMBRANE POTENTIAL
‐ Potential difference (-70mV) across the membrane of a resting neuron – i.e., begins at -
70mV
‐ Changes are caused by 3 events:
• Depolarisation: inside of membrane becomes less negative
• Repolarisation: membrane returns to its resting membrane potential
• Hyperpolarisation: inside of membrane becomes more negative than resting
potential
FLG 327 Alyssa Theron
,NERVOUS SYSTEM
‐ Master controlling & communicating system of the body
‐ Functions:
• Sensory input – monitoring stimuli occurring inside & outside body
• Integration – interpretation of sensory input
• Motor output – response to stimuli by activating effector organs
‐ Information sent
with afferent/ sensory pathway to brain where will find integration, conscious &
subconscious decisions will be made and information will be sent with efferent
pathways/ motor neurons to effectors
AFFERENT AND EFFERENT CNS CONNECTIONS
FLG 327 Alyssa Theron
,HISTOLOGY OF NERVE TISSUE
‐ 2 principal cell types of nervous system:
• Neurons – excitable cells that transmit electrical signals
• Supporting cells – cells that surround and wrap neurons
MYELIN SHEATH
‐ Whitish, fatty (protein-lipoid), segmented sheath around most long axons
‐ Functions to:
• Protect the axon
• Electrically insulate fibers from one another
• Increase the speed of nerve impulse transmission
CONDUCTION VELOCITIES OF AXONS
‐ Conduction velocities vary widely among neurons
‐ Rate of impulse propagation is determined by:
• Axon diameter – larger diameter = faster impulse
• Presence of myelin sheath – myelination increases impulse speed
FLG 327 Alyssa Theron
, TYPES OF SYNAPSES – NEURON CLASSIFICATION
‐ Structural:
• Multipolar – 3/ more processes
• Bipolar – 2 processes (axon & dendrite)
• Unipolar – single, short process
‐ Functional:
• Sensory (afferent) – transmit impulses towards CNS
• Motor (efferent) – carry impulses away from CNS
• Interneurons (association neurons) – shuttle signals through CNS pathways
GLIAL CELLS
‐ Glial cell – also known as supporting cells
‐ when answering in tests make sure to first indicate if cell is found in peripheral or
central nervous system
SYNAPSES
‐ junction that mediates information transfer from one neuron:
• to another neuron
• to an effector cell
‐ presynaptic neuron – conducts impulses towards synapse
‐ postsynaptic neuron – transmits impulses away from synapse
FLG 327 Alyssa Theron
ESSENTIAL NEUROPHYSIOLOGICAL CONCEPTS
CHANGES IN MEMBRANE POTENTIAL
‐ Potential difference (-70mV) across the membrane of a resting neuron – i.e., begins at -
70mV
‐ Changes are caused by 3 events:
• Depolarisation: inside of membrane becomes less negative
• Repolarisation: membrane returns to its resting membrane potential
• Hyperpolarisation: inside of membrane becomes more negative than resting
potential
FLG 327 Alyssa Theron
,NERVOUS SYSTEM
‐ Master controlling & communicating system of the body
‐ Functions:
• Sensory input – monitoring stimuli occurring inside & outside body
• Integration – interpretation of sensory input
• Motor output – response to stimuli by activating effector organs
‐ Information sent
with afferent/ sensory pathway to brain where will find integration, conscious &
subconscious decisions will be made and information will be sent with efferent
pathways/ motor neurons to effectors
AFFERENT AND EFFERENT CNS CONNECTIONS
FLG 327 Alyssa Theron
,HISTOLOGY OF NERVE TISSUE
‐ 2 principal cell types of nervous system:
• Neurons – excitable cells that transmit electrical signals
• Supporting cells – cells that surround and wrap neurons
MYELIN SHEATH
‐ Whitish, fatty (protein-lipoid), segmented sheath around most long axons
‐ Functions to:
• Protect the axon
• Electrically insulate fibers from one another
• Increase the speed of nerve impulse transmission
CONDUCTION VELOCITIES OF AXONS
‐ Conduction velocities vary widely among neurons
‐ Rate of impulse propagation is determined by:
• Axon diameter – larger diameter = faster impulse
• Presence of myelin sheath – myelination increases impulse speed
FLG 327 Alyssa Theron
, TYPES OF SYNAPSES – NEURON CLASSIFICATION
‐ Structural:
• Multipolar – 3/ more processes
• Bipolar – 2 processes (axon & dendrite)
• Unipolar – single, short process
‐ Functional:
• Sensory (afferent) – transmit impulses towards CNS
• Motor (efferent) – carry impulses away from CNS
• Interneurons (association neurons) – shuttle signals through CNS pathways
GLIAL CELLS
‐ Glial cell – also known as supporting cells
‐ when answering in tests make sure to first indicate if cell is found in peripheral or
central nervous system
SYNAPSES
‐ junction that mediates information transfer from one neuron:
• to another neuron
• to an effector cell
‐ presynaptic neuron – conducts impulses towards synapse
‐ postsynaptic neuron – transmits impulses away from synapse
FLG 327 Alyssa Theron
