Nervous System Review and Neurophysiology Flashcards

Comprehensive fill-in-the-blank practice flashcards covering nervous system anatomy, resting and action potentials, ion channels, synapse types, summation, neurotransmitters, and neural circuits.

The Central Nervous System (CNS) is composed of the brain and the __________.

Spinal cord

Concentrations of cell bodies located outside the Central Nervous System in the Peripheral Nervous System are called __________.

Ganglia

The afferent division of the PNS carries sensory signals from the somatic sensory division, special senses, and the __________ sensory division.

Visceral

The somatic motor system sends motor nerve fibers to skeletal muscle and is under __________ control.

Voluntary

The autonomic motor system regulates smooth muscle, heart rate, and glands, and is under __________ control.

Involuntary

The adult human brain contains approximately __________ neurons.

$$86,000,000,000$$

A neuron structural type with one axon and multiple dendrites is classified as a __________ neuron.

Multipolar

A neuron structural type with one axon and one dendrite is classified as a __________ neuron.

Bipolar

Anaxonic neurons have many dendrites but no axon and act as non-spiking interneurons, such as retina __________ cells.

Horizontal

Interneurons are typically multipolar and make up __________ of all neurons in the human body.

$$99\%$$

The cerebrum is the largest part of the brain, accounting for __________ of its volume.

$$83\%$$

The brainstem is comprised of the midbrain, pons, and __________.

Medulla oblongata

Outer layers of grey matter located around the surface of the cerebrum and cerebellum form the __________.

Cortex

Deeper masses of grey matter in the brain that are surrounded by white matter are called __________.

Nuclei

Although the brain makes up only about $2\%$ of body mass, it receives __________ of total blood flow ($750\,ml/min$).

$$15\%$$

The Blood-Brain Barrier consists of brain tissue capillaries lined with tight __________ cells.

Endothelial

The Blood-CSF Barrier is formed by tight junctions between __________ cells of the choroid plexuses.

Ependymal

In the limbic system, the __________ is responsible for primary memory.

Hippocampus

In the limbic system, the __________ is associated with feelings of anger and fear.

Amygdala

The superior and inferior colliculi are located in the midbrain and govern visual and __________ reflexes.

Auditory

Autonomic functions such as swallowing, respiration, heart rate, and blood pressure are controlled by the __________ oblongata.

Medulla

Separated electrical charges across a cell membrane represent stored __________ energy.

Potential

The movement or flow of charge between two points is defined as __________.

Current

At resting membrane potential, the concentration of $Na^+$ is high outside the cell, while the concentration of __________ is high inside the cell.

$$K^+$$

Neuronal cell membranes at rest are __________ times more permeable to $K^+$ than to $Na^+$.

$$25\text{x}$$

The $Na^+/K^+$ pump maintains ion gradients by pumping __________ $Na^+$ ions out of the cell for every __________ $K^+$ ions pumped in.

$3$; $2$

Voltage-gated $Na^+$ channels possess two gates: an activation gate and an __________ gate.

Inactivation

In a depolarized membrane, the __________ conformation of the voltage-gated $Na^+$ channel is more stable than its open conformation.

Inactivated

Graded potentials occur at the __________ zone of a neuron and are driven by chemical or mechanical signals.

Input

Action potentials are initiated at the __________ zone when a graded potential reaches threshold.

Summation

During the depolarization phase of an action potential, membrane potential driven by $Na^+$ influx reaches a peak of __________.

$$+30\,mV$$

During repolarization, voltage-gated $Na^+$ channels become inactivated and voltage-gated __________ channels open.

$$K^+$$

Hyperpolarization occurs because voltage-gated $K^+$ channels stay open __________ than needed to reach resting potential.

Longer

Saltatory conduction describes action potential propagation along myelinated axons, jumping between gaps called __________.

Nodes of Ranvier

Nerve fibers classified as Type __________ have the largest diameter, are myelinated, and conduct signals super fast.

A

Type C nerve fibers have the smallest diameter, are __________, and conduct signals super slowly.

Non-myelinated

At chemical synapses, signal transmission experiences a delay of approximately __________.

$$0.5\,ms$$

Electrical synapses allow direct flow of ions between cytosol through gap junctions made of protein complexes called __________.

Connexons

An Excitatory Postsynaptic Potential (EPSP) causes local __________ of the postsynaptic membrane.

Depolarization

An Inhibitory Postsynaptic Potential (IPSP) causes local __________ of the postsynaptic membrane.

Hyperpolarization

Temporal summation occurs when multiple EPSPs are produced by a single synapse in __________ succession.

Rapid

Spatial summation occurs when EPSPs produced nearly __________ by different synapses on the same neuron add together.

Simultaneously

Receptors that contain both a neurotransmitter binding site and an ion channel in a single protein are called __________ receptors.

Ionotropic

Ionotropic receptors that respond to excitatory neurotransmitters open __________ channels.

Cation

Ionotropic receptors that respond to inhibitory neurotransmitters open __________ channels.

Anion (Cl-)

Metabotropic receptors lack an internal ion channel and instead influence channels indirectly via __________ mechanisms.

G protein

Acetylcholine acts as an inhibitory neurotransmitter in heart pacemaker cells by binding to metabotropic receptors that open __________ channels.

$$K^+$$

The intensity of a stimulus is encoded in the nervous system by the __________ of action potentials at the trigger zone.

Frequency

Stimulating additional neurons with higher thresholds as stimulus strength increases is a phenomenon called __________.

Recruitment

Biogenic amines (monoamines) are neurotransmitters synthesized from amino acids by removing the __________ group ($-COOH$).

Carboxyl

Caffeine acts as a stimulant by blocking receptors for the brain's inhibitory purine neurotransmitter named __________.

Adenosine

Endorphins are neuropeptides ranging from 2 to 40 amino acids in length that act naturally to reduce __________ signals.

Pain

Substances that do not directly produce EPSPs or IPSPs but alter the strength of synaptic transmission are called __________.

Neuromodulators

In a neural pool, the __________ zone contains postsynaptic cells with enough synapses for an input neuron to directly trigger an action potential.

Discharge

In a neural pool, the __________ zone contains cells that receive fewer synapses and need additional input from other neurons to reach threshold.

Facilitated

A neural pathway where one presynaptic neuron branches to communicate with many downstream neurons is a __________ circuit.

Diverging

A neural pathway where inputs from many presynaptic neurons come together onto fewer postsynaptic neurons is a __________ circuit.

Converging

A neural circuit that uses a feedback loop to produce repetitive output, such as during breathing inhalation, is a __________ circuit.

Reverberating

A parallel after-discharge circuit continues sending output after a stimulus stops because parallel pathways have differing numbers of __________.

Neurons

Cocaine produces overstimulation in reward pathways by blocking transporter proteins responsible for the reuptake of __________.

Dopamine

MDMA (ecstasy) targets neurons that release __________, causing a massive release that can damage neurons over time.

Serotonin

In the basic functional model of the nervous system shown in the figure, sensory input leads to integration, which then drives a motor response in __________ organs.

Effector

According to the structural organization chart shown in the image, the Peripheral Nervous System is split into the motor division and the __________ division.

Sensory

As illustrated in the synapse comparison diagram, electrical synapses allow direct flow of ions between cells via gap junctions made of tubular protein structures called __________.

Connexons

In the neural summation diagram shown, __________ summation occurs when excitatory graded potentials originating from many different neurons trigger an action potential together.

Spatial