Untitled Flashcards Set

Resting Membrane Potential (RMP)

The electrical potential of a cell when not actively conducting an action potential, typically around -70 mv.

Threshold Potential

The critical level to which a membrane potential must be depolarized in order to initiate an action potential; typically around -55 mv.

Depolarization

The process during an action potential where the membrane potential becomes less negative, usually leading to a positive peak around +10 mv.

Repolarization

The process of restoring the cell membrane potential to a more negative value following depolarization.

Overshoot

The phase in an action potential where the membrane potential goes beyond the resting membrane potential due to slow K+ channel closing.

NA/K Pump

A mechanism that actively transports 3 Na+ ions out of the cell and 2 K+ ions into the cell, using ATP to maintain the electrochemical gradient.

Glutamate

The primary excitatory neurotransmitter in the nervous system.

GABA (Gamma-Aminobutyric Acid)

The primary inhibitory neurotransmitter in the nervous system.

Chemoreceptors

Sensory receptors that transduce chemical substances into biological signals, sensitive to changes in the chemical environment.

Photoreceptors

Sensory receptors that transduce light into biological signals, critical for vision.

Mechanoreceptors

Receptors that respond to mechanical pressure or distortion.

Proprioceptors

Sensory receptors located in muscles, tendons, and joints that provide information about body position and movement.

Rods

Photoreceptors sensitive to light, responsible for scotopic (dim light) vision.

Cones

Photoreceptors responsible for photopic (bright light) vision, color vision, and visual acuity.

Golgi Tendon Organs (GTO)

Proprioceptors that sense muscle tension and protect against excessive force.

Muscle Spindles

Proprioceptors that detect changes in muscle length and provide information about muscle stretch.

Alpha Motor Neurons

Neurons that directly innervate extrafusal muscle fibers to cause contraction.

Gamma Motor Neurons

Neurons that innervate intrafusal fibers in muscle spindles to adjust sensitivity.

Phototransduction Cascade

The process through which light photons absorbed by opsins in photoreceptors result in changes to cellular signaling pathways.

Thermoreceptors

Sensory receptors that respond to changes in temperature.

Baroreceptors

Mechanoreceptors that sense pressure changes in blood vessels.

Pacinian Corpuscles

Mechanoreceptors that respond to deep pressure and vibration.

Meissner's Corpuscles

Mechanoreceptors that detect light touch and vibration.

Ruffini Endings

Mechanoreceptors that respond to stretch and sustained pressure.

Photopsin

The type of opsin protein found in cone photoreceptors, involved in color vision.

Rhodepsin

The type of opsin protein found in rod photoreceptors, involved in low light vision.

Alpha-Gamma Coactivation Hypothesis

The theory that during voluntary muscle contractions, both alpha and gamma motor neurons are activated simultaneously to maintain muscle spindle sensitivity.

Nociceptors

Sensory receptors that respond to potentially damaging stimuli, signaling pain.

Homeostasis Regulation

The process by which the body maintains stable internal conditions, including blood pressure and chemical concentrations.