Nervous System Flashcards

The central nervous system (CNS: brain and spinal cord) and the peripheral nervous system (PNS: cranial and spinal nerves connecting the CNS to the body).

Cell body (soma), dendrites (receive signals), and axon (transmits signals away from the cell body to other cells).

A fatty insulating layer around axons formed by Schwann cells (PNS) or oligodendrocytes (CNS). It speeds up nerve impulse conduction via saltatory conduction.

Sensory (afferent) neurons carry signals to the CNS, motor (efferent) neurons carry signals from the CNS, and interneurons connect neurons within the CNS.

The electrical charge difference across a neuron's membrane at rest, approximately -70 mV, maintained by the sodium-potassium pump (3 Na+ out, 2 K+ in).

A rapid, all-or-none reversal of membrane polarity that propagates along an axon. It involves depolarization (Na+ influx) followed by repolarization (K+ efflux).

The membrane voltage (about -55 mV) that must be reached for voltage-gated Na+ channels to open and trigger an action potential.

The rapid jumping of action potentials from one node of Ranvier to the next along a myelinated axon, greatly increasing conduction speed.

The junction between two neurons (or a neuron and effector cell) where signals are transmitted, typically via neurotransmitters released across a synaptic cleft.

An action potential triggers Ca2+ influx at the axon terminal, causing vesicles to release neurotransmitters into the synaptic cleft, which bind receptors on the postsynaptic cell.

Acetylcholine (muscle contraction, memory), dopamine (reward, motor control), serotonin (mood, sleep), GABA (inhibition of neural activity).

An EPSP (excitatory postsynaptic potential) depolarizes the membrane, making firing more likely. An IPSP (inhibitory postsynaptic potential) hyperpolarizes it, making firing less likely.

Cerebrum (higher thinking), cerebellum (coordination, balance), diencephalon (thalamus, hypothalamus), and brainstem (midbrain, pons, medulla oblongata).

Frontal (reasoning, motor), parietal (somatosensory), temporal (hearing, memory), and occipital (vision).

Regulates homeostasis including body temperature, hunger, thirst, circadian rhythms, and controls the pituitary gland to link the nervous and endocrine systems.

Controls involuntary vital functions such as heart rate, blood pressure, and respiratory rhythm. It is located in the lower brainstem.

Acts as the brain's relay station, routing sensory information (except smell) to the appropriate areas of the cerebral cortex for processing.

Receptor, sensory neuron, integration center (CNS interneuron or synapse), motor neuron, and effector (muscle or gland).

Reflex arcs are processed at the spinal cord level without requiring brain involvement, reducing the neural pathway and response time.

Sympathetic ('fight or flight' — increases heart rate, dilates pupils) and parasympathetic ('rest and digest' — slows heart rate, stimulates digestion).

Sympathetic postganglionic neurons release norepinephrine; parasympathetic postganglionic neurons release acetylcholine.

A selective barrier formed by tight junctions between capillary endothelial cells in the brain. It protects the CNS by restricting passage of pathogens and large molecules.

Non-neuronal support cells of the nervous system. They insulate axons (Schwann cells, oligodendrocytes), provide structural support (astrocytes), and perform immune defense (microglia).

It relays sensory and motor signals between the brain and body, and serves as an integration center for spinal reflexes.