Neurons and Nerve Impulses
This stage of the action potential occurs when sodium rushes into the cell.
What is depolarization?
The gap between neurons where chemical communication occurs.
What is the synaptic cleft?
Reflex where tapping the patellar tendon causes quadriceps contraction.
What is the stretch (myotatic) reflex?
These receptors detect tissue damage and rarely adapt.
What are nociceptors?
This clear fluid cushions and nourishes the brain and spinal cord.
What is cerebrospinal fluid (CSF)?
A dermatome is defined as this.
What is an area of skin supplied by a single spinal nerve?
This structure acts as the “information highway” between the brain and body, contains ascending (sensory) and descending (motor) tracts, and ends at approximately the level of L2 before extending into the cauda equina.
What is the spinal cord?
This pump restores resting membrane potential by moving 3 sodium out and 2 potassium in.
What is the sodium–potassium pump?
These vesicles release neurotransmitters into the synapse.
What are synaptic vesicles?
Receptors that detect stretch inside muscle fibres.
What are muscle spindles?
These detect low‑frequency vibration and texture — used in reading Braille.
What are Meissner corpuscles?
Region of the brain responsible for balance, coordination, and muscle tone.
What is the cerebellum?
This condition involves demyelination of CNS neurons, causing sensory & motor deficits.
What is multiple sclerosis?
The principle that states a neuron fires fully or not at all.
What is the all‑or‑none law?
This neurotransmitter is essential for muscle contraction.
What is acetylcholine?
Reflex mediated by Golgi tendon organs that reduces muscle tension.
What is autogenic inhibition (inverse stretch reflex)?
These receptors detect deep vibration and pressure changes, adapting rapidly.
What are Pacinian corpuscles?
The brain’s relay station for all sensory information except smell.
What is the thalamus?
This neurodegenerative disease causes tremors, rigidity, and diminished dopamine.
What is Parkinson disease?
This period briefly prevents a neuron from firing again.
What is the refractory period?
These medications increase neurotransmitter levels by blocking reuptake.
What are SSRIs or SNRIs?
Reflex triggered when stepping on a tack, causing instant leg withdrawal.
What is the withdrawal (flexor) reflex?
These detect changes in blood electrolyte balance and stimulate thirst.
What are osmoreceptors?
This brainstem region regulates autonomic functions like heart rate and breathing.
What is the medulla oblongata?
These sudden bursts of uncontrolled electrical activity may be focal or generalized.
What are seizures?
Impulse conduction that “jumps” between nodes of Ranvier.
What is saltatory conduction?
The type of signal transfer after neurotransmitter binding — converting chemical to electrical.
What is postsynaptic depolarization (or synaptic transmission)?
Reflex that stabilizes the opposite side of the body during withdrawal.
What is the crossed‑extensor reflex?
These detect body position and movement and reside in muscles, joints, and tendons.
What are proprioceptors
White matter contains these; gray matter contains their cell bodies.
What are myelinated axons (white) and unmyelinated axons, dendrites, and cell bodies (gray)?
This injury can cause quadriplegia or paraplegia depending on its level.
What is a spinal cord injury?