LC 3-12 Flashcards
Connection between nerve and another nerve, or a nerve and a muscle or gland
synapse
Two type of synapses
chemical and electrical
Type of synapse that is least common and much faster, found in eyes and brain
electrical synapse
Most common type of synapse, slower, found everywhere but portions of brain and eyes
chemical synapse
Small physical gap between neurons in chemical synapses
synaptic cleft/gap
Chemicals that carry signal across synaptic cleft/gap
neurotransmitters
Time between neurotransmitter release and detection by binding neuron
synaptic delay
Neurotransmitters recycle slower than they are used in a synapse
Synaptic fatigue
Neurons between sensory and motor neurons, process information, found only in the CNS, multipolar, 99% of neurons
interneurons
Three functional types of neurons
sensory, motor, and interneurons
Two classification of nervous system
structural and functional
Two branches of the Structural Nervous System
Central Nervous System and Peripheral Nervous System
Portion of the Structural Nervous System composed of the brain and spinal cord
Central Nervous System
Portion of the Structural Nervous System composed of named nerves (including cranial nerves) and ganglia
Peripheral Nervous System
Groups of neuron cell bodies in the PNS
Ganglia
Two branches of Functional Nervous System
Sensory Nervous System and Motor Nervous System
Nervous system that detects, send signals to brain
Sensory Nervous System
Neurons that send signals to brain
Afferent neurons
Which nervous system is afferent
Sensory Nervous System
Which nervous system is efferent
Motor Nervous System
Two branches of the Sensory Nervous System
Somatic Sensory, Visceral Sensory
Nervous system for conscious sensory, known feelings
Somatic Sensory
Nervous system for not conscious sensory
Visceral Sensory
Nervous system that detects eg sight, hot/cold, tasting, pain
Somatic Sensory
Nervous system that detects eg blood values like calcium, glucose
Visceral Sensory
Nervous system that acts, sends signals from brain
Motor Nervous System
Neurons that send signals from brain
Efferent Neurons
Two branches of the Motor Nervous System
Somatic Motor, Autonomic Motor
Nervous system for voluntary motor
Somatic Motor
Nervous system for non-voluntary motor
Autonomic Motor
Nervous system that does eg move arms, breathing, blinking
Somatic Motor
Nervous system that does eg heart rate, mouth watering, going to bathroom, release of insulin/adrenaline, pupil dilation
Autonomic Motor
Two branches of the Autonomic Motor System
Sympathetic, Parasympathetic
Nervous system for fight or flight emergency
Sympathetic
Nervous system for rest and digest
Parasympathetic
List the general functions of the nervous system
Collect Information, Process and evaluate information, Initiate response to information
Specialized nervous system structures that monitor changes in the internal and external environment
receptor
Changes in the internal and external environment
stimulus
All three types of muscle tissue and glands that respond to the control center
effector
Nervous system composed of the brain and spinal cord
central nervous system
Nervous system composed of nerves and ganglia
peripheral nervous system
What are the two functional divisions of the nervous system
Sensory nervous system, motor nervous system
Sensory input that is consciously perceived from receptors (e.g., eyes, ears, and skin)
somatic sensory
Sensory input that is not consciously perceived from receptors of blood vessels and internal organs (e.g., heart)
Visceral sensory
Motor output that is consciously or voluntarily controlled; effector is skeletal muscle
somatic motor
Motor output that is not consciously or is involuntarily controlled; effectors are cardiac muscle, smooth muscle, and glands
Autonomic motor
What are the five distinguishing features common to all neurons
excitability, conductivity, secretion, extreme longevity, amitotic
This is responsiveness to a stimulus (e.g., chemical, stretch, pressure change). The stimulus causes a local change in the resting membrane potential in the excitable cell. Local electrical changes are called graded potentials.
Excitability
This involves an electrical change that is quickly propagated along the plasma membrane as voltage-gated channels open sequentially during an action potential.
Conductivity
Neurons release neurotransmitters in response to conductive activity. Neurotransmitters are stored in vesicles and when released may have either an excitatory or an inhibitory effect on their target structures (other neurons or effectors).
Secretion
What are the two types of synapses
electrical and chemical
Type of synapse where presynaptic neuron and a postsynaptic neuron physically bound together. Gap junctions are present in the plasma membranes of both neurons and facilitate the flow of ions between the cells
Electrical Synapse
Type of synapse composed of a presynaptic neuron, which is the signal producer, and a postsynaptic neuron, which is the signal receiver or target. The two neurons are separated by an extremely narrow fluid-filled gap (of about 30 nanometers) called the synaptic cleft.
Chemical Synapse
The time between the neurotransmitter release from the presynaptic cell, its diffusion across the synaptic cleft, and neurotransmitter binding to receptors in the postsynaptic plasma membrane. This delay is usually between 0.3 and 0.5 milliseconds.
synaptic delay
What are the components of the chemical synapse
presynaptic neuron, postsynaptic neuron, synaptic cleft
The signal producer in a chemical synapse
presynaptic neuron
The signal receiver in a chemical synapse
postsynaptic neuron
An extremely narrow fluid-filled gap (of about 30 nanometers) in a chemical synapse
synaptic cleft
What is the plasma membrane of a neuron called
neurollema
What two types of pumps are found in the plasma membrane
Na+/K+ pumps and Ca2+ pumps
What are the types of channels found in the plasma membrane
Leak channels, Chemically-gated channels, Voltage-gated Channel
Type of plasma membrane channel that is always open
Leak channels
Type of plasma membrane channel that is normally closed, open in response to binding of neurotransmitter
Chemically-gated channels
Type of plasma membrane channel that is normally closed, open in response to electrical charge across membrane
Voltage-gated Channel
What are the three states of voltage-gated Na+ channels
Resting state, Activation State, Inactivation state
What are the functional segments in a neuron
Receptive Segment, Initial Segment, Conductive Segment, Transmissive Segment
Where are the chemical gated channels located on a neuron
in the receptive segment
Where are the voltage-gated channels located on a neuron
in the initial segment
Where are the leak channels located on a neuron
throughout the entire plasma membrane
What ions are more prevalent in the interstitial fluid? In the cytosol?
Cl- and Na+ are
What is the net electrochemical gradient movement of K+
Potassium moves out of the cell
What is the net electrochemical gradient movement of Na+
Sodium moves into the cell
The relatively negatively charged cytosol in comparison to the interstitial fluid outside the cell is called
membrane potential
A response which affects the neuron internally but may not lead to the conduction of the overall stimulation due to not meeting the threshold level
Local potential
Changes in membrane potential that vary in size, as opposed to being all-or-none
Graded potential
A triggering event occurs that depolarizes the cell body
Action potential
The amount of difference in electrical charge between two areas that represents potential energy
voltage
How is voltage measured
volts or millivolts (mV)
The movement of charged particles across the barrier that separates the charge difference
current
Membrane potential when the neuron is at rest
resting membrane potential
Critical level to which a membrane potential must be depolarized to initiate an action potential
threshold
Any change in voltage below the threshold value is not sufficient to open voltage-gated channels
Subthreshold
What is the role of Na+/K+ Pumps
Repolarize the neuron
The gain of positive charge within a neuron that occurs to such an extent to change the plasma membrane potential from negative to positive
depolarization
Return of polarity from positive back to negative (the RMP). _______ is due to the opening of voltage-gated K+ channels and the subsequent movement of K+ out of the cell
repolarization
The change in the membrane potential in the negative direction (e.g., −70 mV to −71 mV), which is caused by the opening of either chemically gated K+ channels to allow K+ to exit the neuron or chemically gated C1− channels for C1− to enter the neuron
hyperpolarization
Voltage change approaches threshold making an AP more likely, depolarization, usually the result of opening a Na+ channel
excitatory postsynaptic potential (EPSP)
Voltage change away from threshold making AP less likely, hyperpolarization, making it more negative, usually a result of Cl- or K+ gates
inhibitory postsynaptic potential (IPSP)
Determines whether or not an action potential will be triggered by the combined effects of excitatory and inhibitory signals, both from multiple simultaneous inputs and from repeated inputs
summation
Type of summation involving multiple simultaneous inputs from different neurons
spatial summation
Type of summation involving repeated inputs from the same neuron
temporal summation
Two factors that influence propagation
diameter of axon (faster) and myelination of an axon (faster)
The law that states that when threshold is reached, the action potential is completely initiated; if threshold is not reached, the action potential is not initiated at all
All-or-None law
What is the sequence of physiological events in conduction of a nerve signal
(1) In Receptive Segment, either EPSP or IPSP occurs, (2) In Initial Segment, temporal or spatial summation of EPSP/IPSP determines if threshold is reached, (3) In Conductive Segment, depolarization/repolarization starts action potential and action potential is propagated, (4) In Transmissive Segment, arrival of action potential triggers release of neurotransmitter
Starts when neuron hits threshold and goes until neuron hits resting, will not respond to another signal during this period
absolute refractory period
Requires greater stimulation, action potential is possible if strength of stimulus is strong enough
relative refractory period
What physiological events occur at the synaptic knob with the arrival of an action potential
(1) voltage-gated Ca2+ channels open, (2) Ca2+ enters synaptic knob, (3) Ca2+ triggers release of neurotransmitters from synaptic vesicles by exocytosis
What factors influence the velocity of a nerve signal
diameter of axon (faster) and myelination of an axon (faster)
What are the 4 categories of neurotransmitter
Acetylcholine, biogenic amines, amino acids, neuropeptides
The primary neurotransmitter for moving muscles (occurs at neuromuscular junctions)
acetylcholine
Neurotransmitter that produces inhibitory activity in the brain; important roles in cognition (learning and memory) motivation, behavior, and mood
dopamine
Excites activity in nervous system to promote cognitive function in the brain (learning and memory); most common neurotransmitter in the brain; stroke causes excessive release resulting in neuron death
glutamate
Has various effects in the thalamus, hypothalamus, and spinal cord
epinephrine do
A chemical released from cell that locally regulate or alter response of neurons to neurotransmitters
neuromodulator
What breaks down acetylcholine
Acetylcholinesterase
Has various functions in the brain related to sleep, appetite, cognition (learning, memory), and mood; fluoxetine (Prozac) decreases reuptake; ecstasy increases the release; LSD binds to most ______ receptors
serotonin
Period of time after action potential initiated during which nothing can make nerve fire again
refractory period
Period of time during repolarization in which nerve cannot fire under any circumstances until K+ and Na+ return to their appropriate places
absolute refractory period
Period of time during hyperpolarization which the nerve can fire but it requires more mV to reach threshold
relative refractory period
Brief period of time (hyperpolarization) which makes it harder to reach threshold
inhibitory post synaptic potential (IPSP)
Temporary depolarization which makes it easier to reach threshold
excitatory post synaptic potential (EPSP)
What effects IPSPs and EPSPs significantly
Potassium K+
How does the neuron create potassium imbalance
chemically-gated potassium channels
Adding together graded potentials to reach threshold
summation
Type of summation in which same receptor releases neurotransmitter multiple times
Temporal summation (Stewie)
Type of summation in which multiple neurons release neurotransmitter all at once
spatial summation (19 and counting)
Type of conduction that happens along unmyelinated neurons and electrical charge must run entire length of axon
Continuous conduction
Type of conduction that happens in myelinated axons, in which electrical charge “jumps” from node of Ranvier to node of Ranvier caused by Na+ rushing into node of Ranvier
saltatory conduction
Unmyelinated “gaps” in a myelinated axon
node of Ranvier
Four classes of neurotransmitters
acetylcholine, amino acids, monoamines, neuropeptides
Type of neurotransmitter that is used for all skeletal muscle contractions
acetylcholine
Term describing any receptor site that uses acetylcholine
cholinergic
Amino acid neurotransmitter that tends to be excitatory, found in foods
Glutamate
Amino acid neurotransmitter that can make people crazy
GABA
Monoamine neurotransmitter involved with sleep, memory, mood, digestion, more for normal cycles of things
Serotonin
Serotonin precursor found in poultry
tryptophan
Monoamine neurotransmitter that effects mood, sleep, memory, released in response to more abnormal things
dopamine
Monoamine neurotransmitter released from adrenal glands
epinephrine and norepinephrine
Neuropeptide neurotransmitter that transmits pain signals
Substance P
Neuropeptide neurotransmitter that has inhibitory effect on brain and spinal cord
Adenosine
Neuropeptide neurotransmitter that deals with smooth muscle and effects blood vessel
Nitric oxide
