chapter 2: biology and psychology Flashcards
neurons are
neurons are specialized cells of the nervous system that conduct impulses. they send messages. vary according to function and location
what does the nucleus use and what does it produce
the nucleus of a neuron uses oxygen and nutrients to generate the energy needed to carry out the work of the cell.
glial cells
- Remove dead neurons and waste products
– Nourish and insulate neurons
– Form myelin and play a role in neural
transmission of messages
– Increase with the development of the nervous
system
neurons include
Include a cell body, an axon, and
dendrites, myelin
myelin
- Fat that insulates the axon from electrically
charged atoms, or ions
– Minimizes leakage of the electrical current
what do dendrites do
dendrites in a neuron receive incoming messages from other neurons.
the passage of messages through neuron until axon terminal
the messages enter the neuron through the dendrite and are passed through the axon, sent from the axon terminal.
where do neurotransmitters come from
neurotransmitters are released from the axon terminal.
what happens as kids get older
as a child matures, the axons become longer and dendrites and terminals proliferate. the number of glial cells increases.
myelination
myelination is a part of the maturation process. this allows infants to engage in visual-motor coordination and other activities untill this process reaches a level.
multiple sclerosis
multiple sclerosis, myelin is replaced with a hard fibrous tissue that throws off the timing of nerve impulses and disrupts muscular control.
afferent neurons (sensory neurons)
receptors or sensory neurons that are near the surface of the skin.Transmit messages from sensory receptors to the spinal cord and brain
efferent neurons (motor neurons)
transmit messages from the brain/spinal cord to muscles and glands. Transmit messages from the brain or spinal cord to muscles and glands
luigi galvani (1737–1798))
conducted an experiemnt in a rainstorm with frogs and wires. he was able to demonstrate the message - neural impulses - that travel along neurons are ELECTROCHEMICAL in nature
neural impulses
- Electrochemical messages that travel
within neurons - Neurons contain negatively or positively
charged ions - Difference in electrical charge polarizes a
neuron for firing
– Firing: Conduction of neural impulse along a
neuron
polarization
to ready a neuron for firing by creating an internal negative charge in relation to the body fluid outside the cell membrane.
resting potential
the electrical potential across the neural membrane when is it not responding to other neurons
depolarized (positively charged)
to reduce the resting potential of a cell membrane from about 70 millivolts toward zero.
depolarization
when area on the resting neuron is stimulated
action potential
the electrical impulse that provides the basis for the conduction of a neural impulse along an axon of a neuron
neural impulse as it progesses
the strength does not change because it is being created anew as it progresses.
all-or-none principle
the fact that a neuron fires an impulse of the same strength whenever its action potential is triggered
threshold
strength of the incoming messages required by a neuron to fire
refractory period
a phase following firing during which a neuron is less sensitive to messages from other neurons and will not fire. “recovery” time
synapse
a junction between the axon terminals of one neuron and the dendrites or cell body of another neuron
synaptic cleft
fluid-filled gap between the axon terminal and dendrite
neurotransmitters
Chemical substances
* Present in the synaptic vesicles of axon
terminals
* Have unique chemical structures and fit
into specific receptor sites
– Loose neurotransmitters are either broken
down or reabsorbed by the axon terminal
(reuptake)
Excitatory and inhibitory functions
determine whether a neuron will fire
– Excite: Cause other neurons to fire
– Inhibit: Prevent other neurons from firing
* Involved in physical processes and
psychological processes
* Excess or deficiency is linked to
psychological disorders
receptor sites
Loose neurotransmitters are either broken
down or reabsorbed by the axon terminal
(reuptake)
excite and inhibit
Excite: cause other neurons to fire
inhibit: prevent other neurons from firing
types of neurotransmitters
Acetylcholine
Dopamine
Norepinephrine
Serotonin
Gamma-aminobutyric acid
Endorphins