C2.2 HL only Flashcards
’All or nothing’ system
nerve cells send signals with the same force regardless of the strength impulse causing them to fire
threshold potential
the critical level to which a membrane potential must be depolarized to initiate an action potential
depolarization
a change within a cell, during which the cell undergoes a shift in electric charge distribution, resulting in less negative charge inside the cell compared to the outside
repolarization
the process in which the membrane of a nerve cell returns to its normal electrically charged state after a nerve impulse has passed
hyperpolarization
when the membrane potential becomes more negative than the resting potential at a particular spot on the neuron’s membrane
refractory period
a period immediately followingstimulationduring which anerveor muscle isunresponsiveto further stimulation
oscilloscope
scientific instruments that are used to measure the membrane potential across a neuronal membrane
unmyelinated axon
A neuron in which there is no myelin sheath surrounding the axon
myelinated sensory neurons
their axon is insulated by a myelin sheath with small uninsulated sections along its length
myelinated motor neurons
When the axon is covered with a myelin sheath then the nerve fibre is known as a myelinated motor neuron
Saltatory conduction
the rapid method by which nerve impulses move down a myelinated axon with excitation occurring only atnodes of Ranvier
nodes of Ranvier
gaps in the myelin sheath coating on the neural axon. The myelin allows the electrical impulse to move quickly down the axon. The nodes of Ranvier allow for ions to diffuse in and out of the neuron, propagating the electrical signal down the axon.
Exogenous chemicals
Describes substances within the human body which have arisen from an external source in the diet or environment
Neonicotinoid insecticides
a class of insecticides that are chemically similar to nicotine and are used to control harmful insects in agriculture and urban landscapes
Cocaine
anaddictivestimulant drug made from the leaves of the coca plant; hightens and prolongs the impact of dopmine on synapse
dopamine
a neurotransmitter made in your brain. It plays a role as a “reward center” and in many body functions, including memory, movement, motivation, mood, attention and more
Excitatory neurotransmitters
“excite” the neuron and cause it to “fire off the message,” meaning, the message continues to be passed along to the next cell. Examples of excitatory neurotransmitters include glutamate, epinephrine and norepinephrine.
Acetylcholine
a neurotransmitter, a chemical that carries messages from your brain to your body through nerve cells
Inhibitory neurotransmitters
a type of chemical messenger that prevents or blocks the transmission of a chemical message to another cell
GABA (gamma-aminobutyric acid)
an amino acid that serves as the primary inhibitory neurotransmitter in the brain and a major inhibitory neurotransmitter in the spinal cord
Excitatory Post-Synaptic Potential (EPSP)
the synaptic activation of a neuron caused by the release of neurotransmitters from a presynaptic neuron, leading to a depolarization of the postsynaptic membrane potential
Inhibitory Post-Synaptic Potential (IPSP)
a temporary electrical charge in a neuron’s membrane that makes it harder for the neuron to generate an action potential
Summation
the process by which multiple electrical impulses combine to create a response in a multicellular organism with a neurological system
Thermoreceptors
specialized parts of neurons, or nerve cell endings, that give the body the ability to detect changes in temperature
Photoreceptors
sensory neurons that respond to light by generating electrical signals
Chemoreceptors
specialized cells that detect chemical changes in the body and environment, and send that information to the nervous system
Electromagnetic receptors
sensory receptors that detect electromagnetic radiation, such as light energy and Earth’s magnetic field
Mechanoreceptors
specialized nerve cells that respond to mechanical stimuli, such as pressure, vibration, and sound, by converting them into electrical signals that are sent to the central nervous system
Baroreceptors
stretch receptors that sense blood pressure
Nociceptors
sensory neurons that detect and respond to potentially damaging stimuli, such as heat, pressure, or chemicals, and are responsible for the sensation of pain
pain matrix
a group of brain structures jointly activated by painful stimuli
Capsaicin
A component of certain plants, including cayenne and red pepper, used topically for peripheral nerve pain
consciousness
a dynamic, integrated, multimodal mental process entailed by physical events occurring in the forebrain
neural network
an interconnected population of neurons
Reductionism
a philosophical approach that attempts to explain biological phenomena by breaking them down into smaller components
Emergence
the process by which new biological structures or species emerge, or the properties of groups that can’t be explained by their individual components
