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