The brain and behavior Flashcards
kapittel 4
neurons
the functional building blocks of the nervous system; cells that transmit the electrical activity that underlies psychological processes.
glial cell
from the Greek for “glue”, glial cells surround the neurons, holding them in place, providing the nutrients they need and isolating toxins that would harm them.
synapse
a connection between neurons.
sensory neurons
carry input messages from the sense organs to the spinal cord and brain.
motor neurons
transmit output impulses from the brain and spinal cord to the body´s muscles and organs.
interneurons
perform connective or associative functions within the nervous system.
peripheral nervous system
contains all the neural structures that lie outside the brain and spinal cord.
somatic nervous system
consists of sensory neurons that are specialized to transmit messages from the eye, ears and other sensory receptors, and motor neurons that sed messages from the brain and spinal cord to the muscles that control our voluntary movements.
automatic nervous system
senses the body´s internal functions and controls the glands and the smooth (involuntary) muscles that form the heart, the blood vessels, and the lining of the stomach and intestines.
sympathetic nervous system
has an activation or arousal function, and tends to act as a total unit.
parasympathetic nervous system
for more specific than the sympathetic nervous system in it opposing actions, it affects one or a few organs at the time; in general, it slows down body processes and maintain a state of tranquillity.
homeostasis
a delicately balanced or constant internal state.
central nervous system
contains the brain and the spinal cord, which connects most parts of the peripheral nervous system with the brain.
dendrites
specialized receiving units like antennae that collect messages from neighboring neurons and send them on to the cell body.
axon
conducts electrical impulses away from the cell body to other neurons, muscles or glands.
resting potential
internal difference of around 70 millivolts (mV)
action potential
electrical shift across the neural membrane, which lasts about a millisecond and propagates electrical signals down an axon.
absolute refractory period
period during which the membrane is not equitable and cannot discharge another impulse.
graded potentials
changes in the negative resting potential that do not reach the -50 millivolt action potential threshold.
myelin sheath
a whitish, fatty insulation layer derived from glial cells during development.
synaptic cleft
a tiny gap between the axon terminal and the next neuron.
neurotransmitters
chemicals released by nerve cells that allow them to communicate with one another.
synaptic vesicles
chambers within the axon terminals
receptor sited
large protein molecules embedded in the receiving neurons cell membrane.
re-uptake
the transmitter molecules are taken back into the presynaptic axon terminals.
acetylcholine (ACh)
a neurotransmitter involved I muscle activity and memory.
botulinum bacteria
toxin-forming bacteria, a mild form of which is known commonly as botox.