Advanced Neurophysiology and Brain Architecture

Flashcards on Advanced Neurophysiology and Brain Architecture Review

What are the two main divisions of the nervous system?

Central Nervous System (CNS) and Peripheral Nervous System (PNS)

What does the Central Nervous System (CNS) comprise?

Brain and spinal cord

What is the function of the Peripheral Nervous System (PNS)?

To relay signals between the CNS and the rest of the body

What are the two divisions of the nervous system related to motor control?

Somatic and Visceral (autonomic)

What does the Somatic nervous system control?

Voluntary movements through skeletal muscle innervation

What does the Visceral (autonomic) nervous system regulate?

Involuntary functions involving cardiac muscle, smooth muscle, and glands

What is the function of the Soma (cell body)?

Contains the nucleus and metabolic machinery

What is the function of Dendrites?

Receive synaptic input

What is the function of Axons?

Transmit action potentials away from the soma

What is a Synapse?

Site of communication between neurons

What is the function of a Presynaptic neuron?

Releases neurotransmitter

What is the function of a Postsynaptic neuron?

Responds to neurotransmitter

What is the function of Afferent neurons?

Carry sensory input to the CNS

What is the function of Efferent neurons?

Transmit motor output from the CNS

What is Axonal Transport?

Bidirectional movement of organelles, proteins, and other substances along microtubules within the axon

Where are Multipolar neurons typically found?

Predominate in the CNS; typical motor neurons

Where are Bipolar neurons found?

Found in the retina and olfactory epithelium

Where are Unipolar (pseudounipolar) neurons found?

Found in sensory ganglia of the PNS

What is the function of Astrocytes?

Maintain blood-brain barrier, regulate ion balance

What is the function of Oligodendrocytes?

Myelinate CNS axons

What is the function of Microglia?

Phagocytic immune cells of the CNS

What is the function of Ependymal cells?

Line ventricles; produce cerebrospinal fluid (CSF)

What is the function of Schwann cells?

Myelinate peripheral axons

What is the function of Satellite cells?

Support neurons in sensory and autonomic ganglia

What is White matter?

Myelinated axon tracts

What is Gray matter?

Neuronal cell bodies, dendrites, unmyelinated axons

What is a Nerve fiber?

Individual axon

What is a Nerve?

Bundle of axons (PNS)

What is a Tract?

Bundle of axons (CNS)

What are Nuclei?

Clusters of neuron cell bodies (CNS)

What are Ganglia?

Clusters of neuron cell bodies (PNS)

What is Current?

Movement of charged ions

What does Ohm’s Law (V = IR) state?

Voltage is proportional to current and resistance

What is Electrochemical gradient?

Combined effect of ion concentration and electrical charge across the membrane

What is the function of Chemical gradient?

Drives diffusion

What is Electrical force based on?

Based on membrane potential differences

Where is Na⁺ highly concentrated?

High extracellular concentration

Where is K⁺ highly concentrated?

High intracellular concentration

What occurs at the Equilibrium potential (Eion)?

No net ion movement at this potential

What is the Resting membrane potential (RMP)?

Typically -70 mV; influenced by permeable ion gradients and membrane conductance

What is the function of Leak channels?

Passive ion movement; critical for RMP

What is the function of Voltage-gated channels?

Mediate action potentials

How is RMP affected by ion permeability?

RMP shifts toward the equilibrium potential of the most permeable ion

When does RMP equal Eion?

RMP equals Eion when only one ion is permeable

What is the approximate value of E(Na⁺)?

~ +60 mV

What is the approximate value of E(K⁺)?

~ -90 mV

What is the function of Na⁺/K⁺ ATPase?

Maintains gradients by actively transporting ions

What triggers an action potential?

Triggered by depolarization reaching threshold

What happens when voltage-gated Na⁺ channels open?

Rapid depolarization occurs

What happens when voltage-gated K⁺ channels open?

Repolarization and hyperpolarization occur

What occurs during the absolute refractory period?

No AP possible; Na⁺ channels inactivated

What is required during the relative refractory period?

Requires stronger stimulus

What is Propagation?

Sequential opening of voltage-gated channels

What happens during Saltatory conduction?

APs jump between nodes of Ranvier

What increases conduction speed?

Larger axon diameter

What occurs after AP arrival and Ca²⁺ channel activation?

Neurotransmitter exocytosis

What occurs after Postsynaptic binding?

EPSPs (depolarization) or IPSPs (hyperpolarization)

What is the function of Facilitation/inhibition?

Modulate synaptic strength

What are Ionotropic receptors?

Ligand-gated ion channels; fast

What is the function of the Frontal lobe?

Motor control, executive function

What is the function of the Occipital lobe?

Visual perception

Which part of the Diencephalon relays sensory input?

Thalamus