Comprehensive Review of Neurophysiology

A complete set of flashcards designed to help students master key concepts in neurophysiology, covering topics from cellular mechanisms to complex brain functions.

The Fluid Mosaic Model was proposed by and in 1972.

Singer and Nicolson

proteins span the membrane and function as channels, carriers, or receptors, while proteins are attached to the membrane surface and help in signaling or structural support.

Integral (transmembrane), Peripheral

stabilizes membrane fluidity and are involved in cell recognition and signaling.

Cholesterol, Carbohydrates

regulates entry and exit of substances, while receive chemical signals.

Selective permeability, Receptors

__ membrane potential, signal transmission, and muscle contraction.

Ion channels are essential for maintaining

__ Allow continuous passive movement of specific ions and maintain resting membrane potential.

Leak Channels (Passive Channels)

__ Open or close in response to changes in membrane potential, such as Na⁺ and K⁺ channels in action potentials.

Voltage-Gated Channels

__ Open when a specific chemical (ligand) binds to the channel, such as Acetylcholine binding to nicotinic receptors at neuromuscular junction.

Ligand-Gated Channels (Chemically Gated)

__ Open in response to mechanical stimuli like stretch, pressure, or vibration and are Found in sensory receptors.

Mechanically-Gated Channels

__ Respond to changes in temperature and are Found in sensory neurons for heat or cold detection.

Temperature-Gated Channels (Thermo-sensitive)

__ across the cell membrane is essential for maintaining homeostasis and enabling cellular function.

Transport

In Simple Diffusion, there is movement of small, __ molecules directly through the lipid bilayer.

non-polar

__ Uses carrier proteins or channels and For polar molecules.

Facilitated Diffusion

__ Diffusion of water through a selectively permeable membrane via aquaporins.

Osmosis

__ Direct use of ATP, for example, Na⁺/K⁺ -ATPase pump.

Primary Active Transport

__ Indirect use of ATP using Symport and Antiport.

Secondary Active Transport (Co-transport)

__ For large molecules, via membrane-bound vesicles such as Endocytosis and Exocytosis.

Vesicular Transport (Bulk transport)

The resting membrane potential (RMP) is the __ difference across the cell membrane when the cell is not actively transmitting impulses.

electrical potential

The membrane is much more permeable to __than to Na⁺ at rest, so the inside becomes more negative.

K⁺

This active transport pump expels 3 Na⁺ ions out and brings 2 K⁺ ions in per ATP hydrolyzed which contributes slightly to the negativity of the RMP

Sodium-Potassium Pump (Na⁺/K⁺-ATPase)

action potential (AP) is a rapid, temporary electrical impulse generated in __ cells.

excitable

At resting state, High k+ inside and High Na+ outside while __ channels open.

K+ leak

During Depolarisation, Voltage Gated __ channels open; so inside becomes positive.

Na+

During Repolarisation Voltage Gated __ channels open.

K+

refractory period: No AP possible and refractory period: AP possible but requires stronger stimulus.

Absolute, Relative

AP travels along the membrane without decreasing in amplitude which is known as __

Propagation

In a living body, impulses only conduct in __ direction, which is known as unidirectional.

one

A local response is a small, localized change in membrane potential that is __ in magnitude depending on the stimulus strength.

varies

During Refractoriness, the inactivation of __ channels prevents the cell from firing again immediately.

Na⁺

__ is defined as the ability of a cell or tissue to respond to a stimulus by generating an electrical impulse.

Excitability

The __ is the minimum strength of a stimulus that, when applied for a long duration, can produce an action potential.

Rheobase

The graph that represents relationship between the strength of the stimulus and time needed to excite the tissue is known as __

Strength-Duration Curve

In Unmyelinated Nerve Fibres The impulse travels by __ Conduction.

Continuous

In Myelinated Nerve Fibres, The impulse jumps from node to node – a process known as __ conduction.

saltatory

Once a threshold stimulus is applied, the neuron fires completely with a full action potential which is known as __

All-or-None Law

Largest in diameter and fastest conducting Nerve fibres are __ fibres

A

The functional unit of neuronal communication in the nervous system is __

Synapse

Located at the axon terminal of the transmitting neuron that Contains synaptic vesicles filled with neurotransmitters.

Presynaptic Terminal

They bind to receptors on the postsynaptic membrane causing ion channel opening, leading to postsynaptic potential (either excitatory or inhibitory).

Neurotransmitters

Neurons are connected by gap junctions and Ions flow directly from one neuron to the next in __

Electrical Synapse

Action potential arrives at the presynaptic terminal, Voltage-gated __channels open in Chemical Synapse.

Ca²⁺

__ are chemical substances that allow communication between neurons at chemicalsynapses.

Synaptic transmission

These act quickly and are involved in fast synaptic transmission which is characteristic of __ Neurotransmitters.

Small-Molecule

Larger molecules made of 3 or more amino acids that Act more slowly and modulate longer-term changes: __ Neurotransmitters.

Neuropeptides

_diffuses directly through membranes and is Not stored in vesicles.

Nitric Oxide (NO)

Depends on the type of neurotransmitter and receptor so it can be Excitatory or Inhibitory: __

Action

If an excitatory neurotransmitter binds to its receptors on the postsynaptic membrane, it typically activates ion channels that allow __ ions to flow into the neuron.

sodium(Na+)

In contrast, when an inhibitory neurotransmitter binds to its receptors on the postsynaptic membrane, it typically opens __ channels

chloride (Cl-)

The electrical signal activates dihydropyridine receptors (DHPRs) in the T-tubule membrane, which are mechanically linked to __ receptors on the sarcoplasmic reticulum (SR).

ryanodine

_ refers to the process by which electrical signals in muscle cells lead to mechanical contraction

Electromechanical coupling

Muscle length remains constant; tension changes during __ Muscle Contraction.

Isometric

Muscle tension remains constant; length changes during __ Muscle Contraction.

Isotonic

A single, brief contraction in response to a single stimulus is known as __ Muscle Contraction.

Twitch

Subsequent stimuli arrive before the muscle completely relaxes from the previous twitch, leading to increased tension is known as __ Muscle Contraction.

Wave Summation

Definition: A decrease in muscle's ability to generate force which is known as __ fatigue.

Skeletal Muscle

The __ system prepares the body for 'fight or flight' responses

sympathetic

Triggered by an increase in intracellular calcium ions ([Ca²⁺]) which enters through __channels

voltage-gated

Calcium binds to __ regulatory protein.

Calmodulin

The Ca²⁺-calmodulin complex activates __.

MLCK

MLCP dephosphorylates __chains, stopping cross-bridge cycling and promoting relaxation.

myosin light

These are __ projections that receive signals from other neurons or sensory receptors.

Dendrites

Action potential will be initiated based on the summation of incoming signals by __

Axon Hillock

These are gaps in the myelin sheath where ion exchange occurs also called __

Nodes of Ranvier

Neurotransmitters are released into synapses to communicate with target cell by __ Terminals.

Axon

Communication occurs via neurotransmitters released at synapses between neurons in __ networks .

Neural

Neural network adapt through synaptic strengthening or weakening based on activity . This is called __ .

Plasticity

Multiple input neurons converge onto a single output neuron in __ Networks.

Converging

Neurons form feedback loops, allowing signals to persist or oscillate during __ Networks.

Reverberating

Input signals travel through parallel pathways with varying synaptic delays before converging at an output neuron in __ Networks.

Parallel After-Discharge

In positive feedback it signals, while negative feedback neural activity.

amplifies, stabilizes

These reflexes involve only one synapse between the afferent and efferent neurons called __ reflexes .

Monosynaptic

A reflex is an__ movement or action that occurs in response to stimuli.

involuntary

Multiple simultaneous stimuli from different presynaptic neurons can combine at the postsynaptic neuron, reaching threshold potential and triggering an action potential named __ Summation.

Spatial

Excitation persists for some time after the stimulus ends due to ongoing neurotransmitter activity inside __ .

Nerve centre

Nerve centers can modify incoming rhythmic signals into different output rhythms based on their intrinsic properties a feature called __ .

Rhythm Transformation

A process by which neuronal activity is suppressed, reducing the likelihood of action potential generation in the CNS

Inhibition

Postsynaptic inhibition involves the release of inhibitory neurotransmitters such as __

GABA

During Postsynaptic Inhibition-Cl- channels allows chloride ions (Cl-) to enter the postsynaptic neuron and causing __

hyperpolarization

This involves the inhibition of antagonist muscles when agonist muscles are activated and prevents it from contracting while allowing smooth movement by the agonist

Reciprocal Inhibition

This enhances contrast and sharpens sensory perception by inhibiting neighboring neurons around an excited neuron

Lateral inhibition

The secretion of hormones can be inhibited when their levels reach a certain threshold and preventing overactivity with the help of __Mechanisms.

Negative Feedback

The autonomic nervous system (ANS) has two main branches: The __ system prepares the body for 'fight or flight' responses

Sympathetic

It helps our movements be smooth, for example, when you bend your arm, your biceps work while your triceps let go with __ of CNS coordination.

Principle of Reciprocity

Higher parts of the brain can take charge and influence lower parts, like overriding automatic reactions. This is a feature during __ of CNS coordination.

Principle of Subordination

All signals that tell muscles to move eventually go through the same basic route in the spinal cord during __ of CNS coordination.

Common Final Pathway

During the activity of the sympathetic division, many of the inputs originate in the __

brainstem

The parasympathetic nervous system (PSNS) is primarily responsible for stimulating "__ " activities

rest-and-digest

These are branched projections that receive signals (input) from other neurons or sensory receptors which is characteristic of a __ .

Dendrites

Each column contains neurons that respond to similar types of information or perform similar processing tasks during __ Organisation .

Columnar

Primary sensory cortices are distributed across various lobes but visual cortex location lies in __ lobe.

occipital

Voluntary movements or regulation of muscle tone happens at the __ cord level .

Spinal

The spinal cord plays a critical role in regulating muscle tone and movement through __ mechanisms

reflex

This is a fundamental mechanism that helps maintain muscle tone and posture. It occurs when a muscle is stretched, leading to an automatic contraction of that muscle to resist further stretching is __ Reflex.

Myotatic

This serves as a protective mechanism that prevents excessive tension in muscles known as __ Reflex.

Reverse Myotatic

An important withdrawal response that occurs when a painful stimulus is applied to a limb called __ Reflex.

Flexor

Two types of lower motor neurons that that play crucial roles in the control of muscle contraction and movement called __ neurons.

Alpha and gamma motoneurons

A motor neuron that allows muscle to contract smoothly and precisely is __ motoneuron.

Gamma

The simultaneous activation of alpha and gamma motoneurons is commonly refered as __

Alpha-Gamma Coactivation

This consists of a complex interplay between various neural systems that underpin essential motor functions and postural stability across different life stages and clinical conditions which is characteristic of __ reflexes.

Late tonic brainstem

This play a pivotal role in the planning, control, and execution of voluntary movements

Motor Cortex