Brain, Mind & Behavior Exam #1 Flashcards
Neuron
Basic unit of the nervous system.
What are the 4 functional zones of the neuron
Input, integration, conduction, output
Explain Input (one of 4 functional zones of the neuron)
dendrites receive information from other cells
Explain integration (one of 4 functional zones of the neuron)
cell body (or soma)- integrates the information it receives
Explain conduction (one of 4 functional zones of the neuron)
a single axon (nerve fiber) conducts output information away from the cell body as an electrical impulse
Explain output (one of 4 functional zones of the neuron)
axon terminals at the end of the axon communicate activity to other cells
What are the 3 shapes of neurons
Motor Neurons, Sensory neurons, inter-neurons
Motor Neurons
large, have long axons + stimulate muscles
Sensory Neuron
have various shapes that best respond to specific environments stimuli such as odor, light, or touch
Interneurons
have tiny axons + analyze input from one set of neurons and communicate w/others
Multipolar Neurons
One axon, many dendrites; most common
Bipolar Neurons
1 axon, one dendrite
Unipolar Neurons
a single extension branches in 2 directions forming an input and output zone
How do the neuronal cell body and dendrites interact?
Neuronal cell body + dendrites receive information across synapses. info is transmitted from the presynaptic neuron to the post-synaptic neuron
Presynaptic membrane -
on the axon terminal of the presynaptic neuron
postsynaptic membrane-
on the dendrite or cell body of the post synaptic neuron
synaptic cleft-
the gap that separate the membranes
synaptic vesicles
small spheres in presyntaptic axon terminals that contain a neurotransmitter
when are neurotransmitters released
they are released in response to electrical activity in the axon
neurotransmitter receptors
in the postsynaptic membrane. they are specialized proteins that react to neurotransmitter molecules
Neuroplasticity
continual remodeling of neuronal connections
axon hillock
a cone shaped area of the cell body that gives rise to the axon. converts input into eletrical signals that travel down the axon and innervate target cells
axon collateral
a branch of an axon that also ends in terminals
axon transport
the bidirectional movement of materials with an axon
glial cells
assist neuronal activity by providing raw materals, chemical signals and structure and also participate in information processing
what is myelin
a fatty insulation layer that wraps around axons
what are the two types of myelin
oligodendrocytes and schwann cells
oligondendrocytes
form the myelin sheaths in the brain and spinal cord (its like glue)
Schwann cells
provide myelin to neurons outside the brain and spinal cord
Two other types of glial cells
astrocytes and microglial cells (microglia)
astrocytes
star-shaped cells with many processes that stretch around and between neurons and sometimes blood vessels;
Central Nervous System (CNS)
consists of brain and spinal cord
Peripheral nervous system (PNS)
includes all other parts of the nervous system outside the brain and spinal cord. consists of bundles of nerves
microglial cells (microglia)
tiny mobile cells that remove debris from injured or dead cells
Motor nerves
transmit information from spinal cord to muscles and glands
sensory nerves
convey info from body to CNS
nerves of the body are divided into 2 segments
somatic nervous system and autonomic nervous system
somatic nervous system
nerves that interconnect the brain and major muscles and sensory systems of the body
autonomic nervous system
nerves that connect to the viscera (internal organs). main system for controlling the body’s organs
what are the two divisions of the autonomic nervous system
sympathetic and parasympathetic
sympathetic nervous system
has axons that innervate the sympathetic gonglia (small clusters of neurons outside CNS)- responsible for ‘fight or flight’ response. prepares body for action
parasympathetic nervous system
helps body relax and recuperate. neurons extend longer distances from CNS to parasympathetic ganglia, which are usually close to the organ they work with.
cerebral cortex
outermost layer of brain. is has gyri (ridged portions) and sulci (valley). It has 4 lobes
what are the 4 lobes of the cerebral cortex
frontal, paretal, occipital, temporal
frontal lobe
front obviously. it controls the motor systems
parietal lobe
between frontal and occipital. (like the crown region ish) controls sensations and body awareness.
occipital lobe
back region. controls visual processing
temporal lobe
below the parietal lobe (lateral region). controls auditory processing
what are the 2 types of brain tissue
gray and white matter
gray matter
contains more cell bodies and dendrites, which lack myelin
white matter
consists mostly of axons with white myelin sheaths
basal ganglia
a group of structures near the center of your brain that form important connections. important in motor control and consist mainly consist of the caudate nucleus, putamen, and Globus
limbic system
includes structures important for emotion and learning
what are the 6 parts of the limbic system
amygdala, hippocampus and fornix, cingulate gyrus, olfactory bulb, thalamus, and hypothalamus
amygdala
emotion regulation and perception of odor
hippocampus and fornix
learning
cingulate gyrus
attention
olfactory bulb
sense of smell
thalamus
a cluster of nuclei that relay sensory info
hypothalamus
contain nuclei with many functions; also control the pituitary
midbrain tectum
a section of the midbrain between the hindbrain and the forebrain. contains superior colliculi and interior colliculi
superior colliculi
visual processing
interior colliculi
auditory processing
substantia nigra
part of the basal ganglia
recticular formation
part of midbrain. involved with sleep and arousal
periaqueductal gray
part of midbrain. pain perception
Meninges
protective layer that surrounds brain and spinal cord
3 parts of meninges
dura mater, pia mater, arachnoid membrane
dura mater
tough outermost layer
pia mater
delicate innermost layer
arachnoid membrane
lies between the other two; filled with cerebrospinal fluid (CSF)
what 3 cranial nerves are exclusively sensory
olfactory, optic, vestibulochlear
how many cranial nerves are there
12 pairs
olfactory nerve
smell
optic nerve
vision
vestibulochlear nerve
hearing and balance
what 5 nerves are motor pathways from the brain?
oculomotor, trochlear, abducens, spinal accessory, hypoglossal
oculomotor nerve
eye movement
trochlear nerve
eye movement
abducens nerve
eye movement
spinal accessory
neck muscles nerves
hypoglossal
tongue nerves
what 2 nerves have sensory and motor functions
trigeminal, vagus
trigeminal
facial sensation, chewing muscles
vagus
innervates heart, liver, and intestines
Computer axial tomography (CAT)
a measure of x-ray absorption at several positions around the head. CT scans generate an anatomical map of the brain based on tissue density
magnetic resonance imaging (MRI)
higher resolution images, fewer damaging effects than CT. when protons relax, they emit radio waves that differ by tissue density
Functional MRI (fMRI)
detects small changes in brain metabolism, such as oxygen use, in active brain areas. fMRI can show how networks of brain structures collaborate
Positron emission tomography (PET)
gives images of brain activity. Emissions of radioactive chemicals in the bloodstream indicate their destination. identifies which brain regions contribute to specific functions
Neurophysiology
the study of life processes of neurons.
explain resting neuron
a resting neuron is polarized, meaning there is a difference in electrical charge between the inside and outside of cell
ions
electricity charged molecules
anions
negatively charged
cations
positively charged
ion channels
proteins that span the membrane and can allow ions to pass through. some are gated, opening and closing in response to signals. others stay open all the time, such as the one in neurons that allow only potassium ions (K+) to cross the membrane
how do action potentials ‘move’?
they are actively propogated along the axon. each adjacent section is depolarized and a new action potential occurs. action potentials can only travel in one direction because of the refractory state of the membrane after depolaization
conduction velocity
the speed of propogation of action potentials, varies with axon diameter
what happens when action potential reaches the end of axon
causes the release of neurotransmitter into synapse
excitatory postynaptic potential (EPSP)
a small local depolarizing potential in the postsynaptic membrane that pushes the cell closer to the action potential threshold, increasing the likelihood that the neuron will fire an action potential. (in EPSPs, Na+ channels open, letting positive ions into the cell
inhibitory postsynaptic potential (IPSP)
a hyperpolarizing potential in the postsynaptic membrane that pushes the cell further away from threshold, decreasing likelihood of the neuron firing an action potential
when do IPSP happen
(these result when chloride ions (Cl-) rush into the cell making the inside more negative)
spatial summation
the summary of all the potentials that reach axon hillock from locations across the cell body. If the overall depolarization (sum of IPSP and EPSP) reaches or exceeds threshold, an action potential is produced
the sequence of transmission
- Action potential arrives at the presynaptic axon terminal
- voltage fated calcium channels in the terminal membrane open and ca2+ ions enter
- Ca2+ ions cause synaptic vesicles filled with neurotransmitters to fuse with the presynaptic membrane, releasing the transmitter into the synaptic cleft
- transmitters bind to postsynaptic receptor molecules, causing ion channels to open and leading to an EPSP or IPSP
- EPSP or IPSP spread toward the postsynaptic axon hillock. If threshold is reached, an action potential will occur
- Synaptic transmission is rapidly stopped- accurately reflecting the activity of the presynaptic cell.
- transmitter may activate presynpatic receptors that decrease trasmitter release
Ligands
molecules that fit into receptors and activate or block them. A synapse that uses acetylcholine (ACh) has ligand-binding sites for ACh on neurotransmitter receptor molecules in the postsynaptic membrane. The post-synaptic receptors determine the action of the transmitter. ACh can be excitatory, opening Na+ and K+ channels or it can be inhibitory, opening Cl- channels
how does nicotine work?
some chemicals can fit on receptors in place of a neurotransmitter. nicotine can mimic ACh on receptors acting like the transmitter agonist
how can transmitter action be halted?
degradation and reuptake,
synaptic delay
the delay between an action potential reaching the axon terminal and creating a postsynaptic potential
degradation
the rapid breakdown and inactivation of transmitter by an enzyme (AChE)
Reuptake
transmitter is cleared from the sunapse by being absorbed back into the presunaptic axon terminal.
what are transporters
special receptors that bring the transmitter back inside
types of synapses
axo-dendritic, axo-somatic, aso-asonic, dendro-dentritic
axo-dendritic
the axon terminal synapses on a dendrite
axo-somatic
synapse between axon and cell body (soma)
axo-axonic
synapse between two axons
dendro-dendritic
synapse between 2 dendrites
knee jerk reflex
- sensory and motor axons are myelinated and large
- sensory cells synapse directly onto motor neurons
- both the central synapse and the neuromuscular junction are fast synapses
Electroencephalogram (EEG)
recording of spontaneous brain potentials (brain waves)
event-related potentials (ERPs)
they are EEG responses to a single stimulus such as a flash of light or loud sound. they can distinguish between sleep states and provide data for diagnosing seizure disorders
types of seizures
- Tonic-Clonic or Grand mal Seuzure
- simple, absence or petit mal seizure
- complex partial seizures
Tonic-Clonic or Grand mal Seuzure
abnormal EEG activity throughout the brain
simple, absence or petit mal seizure
brain waves show patterns of seizure activity for 5 to 15 seconds, may occur several times a day
complex partial seizures
do not involve entire brain, often preceded by an unusual sensation
