Neurons and Synapses Flashcards
the study of the physiological, evolutionary, and the developmental mechanism of behavior
and experience
Biological Psychology
three biological systems that we are going to consider as responsible for feeling, thinking, and acting, and directing the activities of the body
the neural system, nervous system, and endocrine system
Spanish histologist
proved that each nerve cell is an
independent entity; father of Neuron Theory
Santiago Ramón y Cajal (1852-1934)
Neuron is from the Greek word
nevronas meaning sinew, cord, nerve
cells that are specialized for the reception, conduction, and transmission of electrochemical signals.
Neuron
It is when the cell’s dendrites and axon are entirely contained
within a single structure.
Interneuron
carries information away from a structure
Motor neuron
The receiver of sensory input, is highly sensitive to a particular type of stimulation, such as light, sound, or touch.
Sensory neurons
It is a neuron with two
processes extending
from its cell body, one dendrite and one axon.
(located in eyes, ear, nose)
Bipolar
It is a neuron with one process extending from its cell body which together comprise an axon (sensory neurons, located in the ganglia)
Unipolar
It is a neuron with
many processes from
the cell body; many dendrites and one axon (located in the brain and spinal cord)
Multipolar
It is a tiny, brief “spike” of electricity traveling through a neuron.
Nerve Impulse
In the absence of any stimulation or when the neuron is not currently receiving or sending messages, the membrane potential is at rest.
Resting potential
in the presence of stimulation or when a neuron is receiving messages sent by the axon, it decreases the negativity of charge inside the membrane, reducing its polarization toward zero (Depolarization), or from negative to positive.
Action potential
After an action potential occurs at a node, sodium ions enter the axon and diffuse, pushing a chain of positive charge along the axon to the next node, or the action potential “jump” from node to node where they regenerate it
Saltatory Conduction
At the peak of action potential, an absolute refractory period occurs where the axon resists the
production of further action potentials regardless of the stimulation, and the sodium ion channel is shut up.
Refractory Period
introduced the term synapse; shed light on knee-jerk reflex
Charles Scott Sherrington (1857–1952)
Synapse is from the Greek terms
“syn-” (together) and
“haptein” (to clasp).
Synapse properties
Speed of Conduction
Temporal Summation
Inhibitory Synapses
Spatial Summation
Reflexes are slower than conduction along an axon.
Speed of conduction
repeated stimuli within a brief time have a cumulative effect; several weak stimuli presented at nearby places or times produce a stronger reflex than one stimulus alone does.
Temporal
Summation
a combination of excitations produced an action potential
Spatial Summation
when one set of muscles becomes excited, a different set becomes relaxed. When one is excited, it produces inhibition to the opposite one, thus, it balances its position.
Inhibitory Synapses
the membrane of one neuron comes into direct contact with the membrane
of another
Electrical Synapse
a gap between two neurons where information passes chemically, in the form of neurotransmitter molecules
Chemical Synapse
it is the process by which one neuron communicates with another; the workings of psychoactive drugs
in the synapse that affects the nervous system of the user.
Synaptic transmission
two major types of nerve cells in the human brain
Neuron and glia
It is a Greek word for “tree”; these branching fibers receive signals from other cells.
Dendrites
It is a Greek word for “body”; plural: so- mata; it contains the nucleus, ribosomes, and mitochondria responsible biochemical processes and integration of synaptic input before transmitting the signal by the axon.
Cell body, or soma
It is a Greek word for for “axis”; it is a thin fiber of constant diameter, conveys an impulse toward other neurons, an organ, or a muscle
Axon
it is the axon’s insulating material
Myelin Sheath
it facilitates the rapid conduction of nerve impulses.
Nodes of Ranvier (RAHN-vee-ay)
It is a French word for “button”. It is also known as an end bulb or bouton),where the axon releases chemicals that cross through the junction between that neuron and another cell.
Presynaptic terminal
the receiver of sensory input, is highly sensitive to a particular type of stimulation, such as light, sound, or touch; an afferent (letter “a” as admit) axon brings information to the interneuron; these are unipolar neurons.
Sensory neurons
It is when the cell’s dendrites and axon are entirely contained within a single structure; it connects the sensory neuron to motor neuron by transmitting the information; these are multipolar neurons.
Interneuron or intrinsic neuron
Usually, its soma is located in the spinal cord; it receives excitation through its dendrites and conducts impulses along its axon to a muscle. an efferent axon carries information away from a structure; efferent starts with e as in exit; these neurons are multipolar neurons.
Motor neuron
the receiving and sending of electrochemical signals throughout the nervous system
Nerve Impulse
carries positive electrical charges
sodium ions and potassium ions
stimulated the heart of a frog with electrical impulses and had it pump a small amount of nutrient solution
Otto Loewi (1921)
At a synapse, a neuron releases chemical that affect another neuron.
Neurotransmitters
Neurons synthesize nearly all neurotransmitters from amino acids, which the body obtains from proteins in the diet.
Synthesis of Transmitters
Most neurotransmitters are synthesized in the presynaptic terminal, near the point of release. The presynaptic terminal stores high concentrations of neurotransmitter molecules in vesicles.
Storage of Transmitters
At the end of an axon, depolarization opens calcium gates in the presynaptic terminal that causes exocytosis or the bursts of release of neurotransmitter from the presynaptic neuron.
Release and Diffusion of Transmitters
Released neurotransmitters activated the the postsynaptic cell
Activating Receptors of the Postsynaptic Cell
This is when ions (sodium, potassium, calcium) pass in response to a neurotransmitter
Ionotropic Effects
When a neurotransmitter attaches to this another group of receptor, it requires g proteins and second messengers to conduct ionic activity in neurons.
Metabotropic Effects
after acetylcholine activates a receptor, the enzyme acetylcholinesterase (a-SEE-til-ko-lih-NES-teh-raze) breaks it into two fragments: acetate and choline; the choline diffuses back to the presynaptic neuron, which takes it up and reconnects it with acetate already in the cell to form acetylcholine again.
Inactivation and Reuptake of Neurotransmitters
