2function Flashcards
cerebrum
associated with higher order
functioning, including the control of voluntary behavior.
Thinking, perceiving, planning, and understanding language
all lie within the cerebrum’s control.
cerebral cortex
The function of the cerebral cortex can be understood
by dividing it somewhat arbitrarily into zones, much like the
geographical arrangement of continents.
frontal lobe
responsible for initiating and
coordinating motor movements; higher cognitive skills, such
as problem solving, thinking, planning, and organizing; and
for many aspects of personality and emotional makeup.
parietal lobe
involved with sensory processes,
attention, and language. in the
parietal cortex, a number of different cortical areas are
concerned with the spatial representation of the body and of
visual and auditory targets around us. They seem to hold a
map of where our limbs are, and where interesting targets
are with respect to us.
occipital lobe
helps process visual information,
including recognition of shapes and colors.
temporal lobe
helps process auditory information and
integrate information from the other senses. Neuroscientists
also believe that the temporal lobe has a role to play in
short-term memory through its hippocampal formation, and in
learned emotional responses through its amygdala.
basal ganglia
The cerebral nuclei help coordinate muscle
movements and reward useful behaviors
thalamus
key part of the forebrain; passes
most sensory information on to the cerebral cortex after
helping to prioritize it
hypothalamus
key part of the forebrain; the control
center for appetites, defensive and reproductive behaviors, and
sleep-wakefulness
colliculi
of the midbrain (it has 2); These collections of neurons play a critical role
in visual and auditory reflexes and in relaying this type of
information to the thalamus.
hindbrain
includes the pons and the medulla
oblongata, which control respiration, heart rhythms, and
blood glucose levels.
cerebellum
The
cerebellum’s two hemispheres help control movement and
cognitive processes that require precise timing, and also play
an important role in Pavlovian learning.
spinal cord
receives sensory information from all parts of the body below the head. It uses this information for reflex
responses to pain, for example, and it also relays the sensory
information to the brain and its cerebral cortex. In addition,
the spinal cord generates nerve impulses in nerves that control
the muscles and the viscera, both through reflex activities and
through voluntary commands from the cerebrum.
myelin sheath
accelerates the
transmission of electrical signals along the axon
glia
perform many jobs. Researchers have known
for a while that glia transport nutrients to neurons, clean
up brain debris, digest parts of dead neurons, and help hold
neurons in place
trophic factors
Researchers have discovered several
small proteins in the brain that act as trophic factors, substances
that are necessary for the development, function, and survival
of specific groups of neurons.
opioid peptides
The precise role of the naturally
occurring opioid peptides is unclear. A simple hypothesis is
that they are released by brain neurons in times of stress to
minimize pain and enhance adaptive behavior
sex hormones
the increased levels of testosterone in males and
estrogen in females act on the hypothalamus and pituitary
to decrease the release of FSH and LH. The increased levels
of sex hormones also induce changes in cell structure and
chemistry, leading to an increased capacity to engage in
sexual behavior. Sex hormones also exert widespread effects
on many other functions of the brain, such as attention,
motor control, pain, mood, and memory.
CO
exact functions for carbon monoxide have
not been determined
NO
nitric oxide
neurotransmission governs erection in the penis. In nerves
of the intestine, it governs the relaxation that contributes
to the normal movements of digestion. In the brain, nitric
oxide is the major regulator of the intracellular messenger
molecule cyclic GMP. In conditions of excess glutamate
release, as occurs in stroke, neuronal damage following the
stroke may be attributable in part to nitric oxide.
prostaglandins
These very small and
short-lived molecules have powerful effects, including the
induction of a fever and the generation of pain in response
to inflammation. Type of lipid messenger. Prostaglandins enhance
the sensitivity of receptors to tissue damage and ultimately
can induce more intense pain sensations. prostaglandins are inhibited by aspirin.
endocannabinoids
These (lipid; membrane-derived) messengers control the
release of neurotransmitters, usually by inhibiting them,
and can also affect the immune system and other cellular
parameters still being discovered. Endocannabinoids play an
important role in the control of behaviors. They increase in
the brain under stressful conditions
ATP
ATP is present throughout the cytoplasm of all cells.
norepinephrine binds to receptors on neuron’s surface –> receptor activated, binds G protein on the inside of the membrane –> activated G protein causes the enzyme adenylyl cyclase to convert ATP to cAMP, the 2nd messenger –> cAMP
exerts a variety of influences within the cell, ranging from
changes in the function of ion channels in the membrane to
changes in the expression of genes in the nucleus
second messengers
After the action of
neurotransmitters at their receptors, biochemical
communication within cells is still possible. Substances that
trigger such communication are called second messengers.
Second messengers convey the chemical message of
a neurotransmitter (the first messenger) from the cell
membrane to the cell’s internal biochemical machinery.
second messengers are also
thought to play a role in
the manufacture and release of neurotransmitters and in
intracellular movements and carbohydrate metabolism in the
cerebrum — the largest part of the brain, consisting of two
hemispheres. Second messengers also are involved in growth
and development processes. In addition, the direct effects
of second messengers on the genetic material of cells may
lead to long-term alterations in cellular functioning and,
ultimately, to changes in behavior.
nicotine
acts through the well-known acetylcholine
nicotinic receptor. This drug can act as both a stimulant and a sedative. Nicotine stimulates the adrenal glands, and the resulting discharge of epinephrine causes a “kick” — a sudden release of glucose paired with an increase in blood pressure, respiration, and heart rate. In addition, nicotine releases dopamine in the brain regions that control motivation, which is one reason that people continue to smoke.
ethanol (general, low vs high)
Ethanol, the active ingredient in alcoholic beverages,
is a seductive drug. At first, it reduces anxiety, tension,
and behavioral inhibitions. In low doses, it may act as a
stimulant, but at higher doses, it acts as a depressant. In both
cases, it significantly alters mood and behavior. Too much
alcohol can also cause heat loss and dehydration
ethanol (neurotransmitters)
The drug, which is easily absorbed into the bloodstream
and the brain, affects several neurotransmitter systems. For
example, alcohol’s interaction with the gamma-aminobutyric
acid (GABA) receptor can calm anxiety, impair muscle
control, and delay reaction time. At higher doses, alcohol
also decreases the function of N-methyl-d-aspartate
(NMDA) receptors, which recognize the neurotransmitter
glutamate. This interaction can cloud thinking and
eventually lead to coma
THC
In radioactive tracing studies, scientists found that
tetrahydrocannabinol (THC), the active ingredient in
marijuana, binds to specific receptors called cannabinoid
receptors, many of which coordinate movement. This may
explain why people who drive after they smoke marijuana
are impaired. The hippocampus, a structure involved with
memory storage and learning, also contains many receptors
for THC. This finding provides some insight into why heavy
users or those intoxicated on marijuana have poor short-term
memory and problems processing complex information.
opiates
Opiates increase the amount of dopamine released in
the brain reward system and mimic the effects of endogenous
opioids (opioid peptides).
heroin
Heroin injected into a vein reaches the brain in 15
to 20 seconds and binds to opiate receptors found in many
brain regions, including the reward system. Activation of
the receptors in the reward circuits causes a brief rush of
intense euphoria, followed by a couple of hours of a relaxed,
contented state.
crack
In 2009, in the United States, an estimated 4.8 million
people age 12 and older had abused cocaine.
psychostimulants
This class of drugs includes cocaine and amphetamines. The key biochemical factor underlying
the reinforcing effects of psychostimulant drugs is their
ability to greatly elevate the brain chemical dopamine
in specific brain regions, such as the nucleus accumbens.
Alterations in dopamine activity in the accumbens,
induced by chronic cocaine intake, are thought to result
in a progressively increasing motivation to take the drugs,
eventually leading to addiction.
rohypnol
When mixed with
alcohol, rohypnol can incapacitate victims and prevent them
from resisting sexual assault. Rohypnol may be lethal when
mixed with alcohol and other depressants.
MDMA
aka ecstasy. a synthetic psychoactive drug with hallucinogenic
and amphetamine-like properties. Users encounter problems
similar to those found with the use of amphetamines and
cocaine. Recent research also links chronic ecstasy use to
long-term changes in those parts of the brain critical for
thought, memory, and pleasure.
GHB
Since about 1990 in the United States, GHB has
been abused for its euphoric, sedative, and anabolic
(body-building) effects. It, too, has been associated with
sexual assault.
special K
Ketamine is another central nervous system
depressant abused as a date-rape drug. Ketamine, or “Special
K,” is a fast-acting general anesthetic. It has sedative,
hypnotic, analgesic, and hallucinogenic properties. It is
marketed in the United States and a number of foreign
countries as a general anesthetic — a drug that brings about
a reversible loss of consciousness — in both human and
veterinary medical practice
apoE
Apolipoprotein E (apoE), which influences susceptibility for Alzheimer’s later in life, exists in three forms. The variant known as APOE epsilon 4 is clearly associated with enhanced risk.
amyloid genes
These genes encode beta and gamma
secretases, which cut amyloid peptide from a larger protein.
The amyloid peptide is then released from the neuron into
the space around synapses, where it can accumulate and form
Alzheimer’s disease plaques. Amyloid-destroying enzymes,
known as alpha secretases, break up the amyloid peptide,
preventing amyloid accumulation.
ALS
affects
neurons that control voluntary muscle movements such as
walking. For reasons that are not completely understood,
motor neurons in the brain and spinal cord begin to
disintegrate. Because signals from the brain are not carried
by these damaged nerves to the body, the muscles begin to
weaken and deteriorate from the lack of stimulation and
resulting disuse.
brain tumor vaccines
vaccines created from
the patient’s own tumor combined with substances that
boost the immune system or kill tumor cells
monoclonal antbodies
hone in on receptors on the surface of
the tumor cells
