Neurophysiology Flashcards
(29 cards)
CNS vs. PNS
SNS vs. PSNS
CNS: brain, brainstem, cerebellum, spinal cord
PNS: peripheral nerves (sensory & motor)
SNS : increases activity of automic functions (HR, BP, BR…)
PSNS: decreases activity of automic function
Spinal Cord level contains?
Walking circuits
Withdrawl reflex circuits
Support against gravity circuit
Circuits for reflexes that control organ functions
Subcortical level involves?
Brainstem (medulla & pons), mesencephalon, hypothalamus, thalamus, cerebellum & basal ganglia
Subcortical level controls?
Subconscious body activities : arterial pressure, respiration, equilibrium, body temperature…
Cortical level controls?
Information processing
Memory storage
Decision making
Thought processes
Somatosensory Axis of NS
transmission of somatic information from receptors to CNS
Info transmitted to : spinal cord, brainstem, cerebellum, thalamus, cerebral cortex
Motor Axis of NS
controlling body activities:
skeletal muscle contration
smooth muscle contraction
exocrine & endocrine glands
What is the function of the Cell body of a neuron?
processes signal (info)
What is the function of the Dendrites of a neuron?
signal input
What is the function of the Axon of a neuron?
signal output
What are the different types of neurons?
Multipolar : several dendrites & one axon
Bipolar : one main dendrites & one axon
Unipolar : one process (dendrite & axon on same side)
Pseudo-unipolar : one process
Where are the different types of neurons found in the body?
Multipolar = motorneuron, purkinje cell Bipolar = retina, inner ear, olfactory Unipolar = photoreceptors in retina Pseudo-unipolar = sensory neuron in spinal cord
How is information transmitted within the neuron?
through Action Potentials (eletrical signals)
How is information communicated between neurons?
by Synapses (chemical signal)
Explain Synaptic Transmission
- AP reaches the presynaptic terminal causing Ca channels to open
- Ca entrers the cell
- Ca causes vesical to fuse with membrane
- NT are released in synaptic cleft
- NT are taken up by receptors
What is a Neurotransmitter?
Chemical substance packaged at the in presnaptic terminal. It is released in the synapse by the arrival of AP. By diffusing across synapse, the NT causes the transfer of the impulse to another neuron or muscle fiber.
What are Excitatory NT?
influences the continuation of AP. excited (depolarize) postsynaptic neuron
Glutamate Dopamine Norepinephrine Acetylcholine Serotonin
What are Inhibitory NT?
inhibit (hyperpolarize) postsynaptic neuron
GABA
Glycine
What are the types of Ionotropic Receptors?
Cation Channels : allows cations (Na+, Ca2+, K+) to pass. These channels excite (depolarize) the postsynaptic neuron (Glutamate receptor)
Anion Channels : allows anions (Cl-) to pass. These channels inhibit (hyperpolarize) the postsynaptic neuron (GABA receptor).
What are Metabotropic Receptors?
(second messenger activator) is a protein struction that causes prolonged changes in neurons by activating substances inside postynaptic neuron (G-protein)
The binding of NT on receptors causes?
opens ion channels and increases the permeability of ions
What is Excitatory postsynaptic potential?
EPSP is caused by activation of excitatory receptors.
Membrane potential moves towards less negative (more positive) values = depolarization
Increase pereability to Na+ and Ca2+ (more positive inside)
What is Inhibitory postsynaptic potential?
IPSP is caused by activation of inhibitory receptors. Membrane potential moves towards more negative (less positive) values = hyperpolarization
Uncreased permeability to Cl - and K+ (more negaive inside)
What are characteristics of Postsynaptic potentials?
Sub-threshold potentials (below threshold of AP)
DO NOT obey All-or-none principal
EPSP favors generation of AP
IPSP blocks generation of AP
