Nervous System Flashcards
(28 cards)
What are the structural and functional organizations of the nervous system?
Central Nervous System (CNS): Brain & spinal cord, processes information.
Peripheral Nervous System (PNS): Nerves outside CNS, sends signals between body and CNS.
What distinguishes the central and peripheral divisions of the nervous system?
CNS: Brain & spinal cord.
PNS: Nerves branching off the CNS.
What distinguishes sensory and motor divisions?
Sensory (afferent): Carries information from body to CNS.
Motor (efferent): Sends commands from CNS to muscles/glands.
What are the distinctions between somatic sensory, visceral sensory, somatic motor, and autonomic motor divisions?
Somatic sensory: Detects external stimuli (e.g., touch, temperature).
Visceral sensory: Detects internal stimuli (e.g., organ function).
Somatic motor: Controls voluntary muscle movement.
Autonomic motor: Controls involuntary functions (e.g., heart rate, digestion).
What is the direction of information transmission through the divisions of the nervous system?
Sensory receptors → Sensory neurons → CNS → Motor neurons → Muscles/Glands.
What are the functions of neurons and neuroglia?
Neurons: Transmit electrical signals.
Neuroglia (glial cells): Support, protect, and nourish neurons.
What causes the color of white matter and gray matter?
White matter: Myelinated axons.
Gray matter: Unmyelinated neurons and cell bodies.
What is the significance of myelination?
Increases speed of nerve impulse transmission.
What is saltatory conduction?
Action potentials jump between nodes of Ranvier in myelinated axons, speeding up transmission.
What is a pathway in the nervous system?
A series of connected neurons that transmit signals.
What distinguishes the location of nerves and tracts?
Nerves: Found in PNS.
Tracts: Found in CNS.
What distinguishes the location of ganglia and nuclei?
Ganglia: Clusters of neuron cell bodies in the PNS.
Nuclei: Clusters of neuron cell bodies in the CNS.
What are the structural components of a neuron?
Dendrites (receive signals), cell body (processes signals), axon (transmits signals).
What is the direction of a nerve impulse along a neuron?
Dendrite → Cell body → Axon → Axon terminal → Next neuron/muscle.
What are the synapse and synaptic cleft?
Synapse: Junction between neurons.
Synaptic cleft: Gap between neurons where neurotransmitters cross.
What is the process of neuron communication?
Electrical signal travels down the axon → Neurotransmitters are released into the synaptic cleft → Bind to receptors on next neuron.
What does signal conduction involve?
A change in the neuron’s membrane potential.
What ions are used to establish and change the neuron’s membrane potential?
Sodium (Na⁺) and potassium (K⁺) ions move in/out of the neuron to create electrical signals.
What is the difference between graded potential and action potential?
Graded potential: Small, local voltage changes.
Action potential: Large, rapid electrical signal traveling down the axon.
Where does graded potential occur in a neuron?
Dendrites and cell body.
Where does action potential occur in a neuron?
Axon.
What is threshold in the context of action potentials?
The minimum voltage needed to trigger an action potential.
What is the significance of the threshold level?
If the threshold is not reached, no action potential occurs.
What is the effect of neurotransmitters binding to ligand-gated ion channels along the dendrites and cell body of a neuron?
It opens ion channels, allowing Na⁺ or K⁺ to enter, leading to depolarization or hyperpolarization.
