Tags & Description
neuron doctrine
brain composed of independent cells; signals transmit on synapses (gaps)
#unipolar
single extension with receptive pole and output zone
#bipolar
one axon, one dendrite; USUALLY SENSORY
#multipolar
one axon, many dendrites; MOST COMMON
#input zone (at dendrites)
collect and integrate info from environment or cells
#integration zone (soma to axon)
decide to make the neural signal
#conduction zone (along axon)
info transmits long distances
#output zone (at terminal buttons)
transfer info to other cells
#what are the two types of brain cells?
neurons and glial cells
#sensory neurons
respond to environment; light, odor, touch
#motoneurons
contact muscles or glands
#interneurons
receive input from and send input to other neurons (most neurons in CNS)
#what are the four types of glial cells?
astrocytes, oligodendrocytes, ependymal cells, microglia
#astrocytes
most numerous glial cell, fill space between neurons for support; regulate ECM composition; stabilizes, brain moves together
#oligodendrocytes
wrap several axons, inside brain and spinal cord; at nodes of Ranvier
#microglia
phagocytes that clean up dying neuron debris; not from the brain, are "immigrants" and clean up; PAC MAN!
#ependymal cell
secrete and absorb cerebral spinal fluid; lines ventricles
#synapse
where two neurons communicate in one direction
#presynaptic neuron
on the terminal buttons of neuron transmitting info
#postsynaptic neuron
on dendrites of neuron receiving info
#neural plasticity
dendritic spines have; immune system cells also able to do this
#dendritic spines form from
DNA and microtubules
#synapse
#peripheral nervous system
include cranial and spinal nerves
#preganglionic neurons
from CNS to autonomic ganglia
#postganglionic neurons
from autonomic ganglia to targets in body
#innervate sympathetic chain
preganglionic cells in spinal cord
#ipsilateral
same side
#anterior
head end
#proximal near center
dorsal toward back
#contralateral
opposite side
#distal
toward periphery
#ventral
toward belly
#posterior
tail end
#afferent flow
sensory; carries impulse into region
#efferent flow
motor, carries impulse away from region
#white matter
made of axon bundles; white because myelin sheaths cover axons
#gray matter
made of cell body clusters
#four cortical lobes
frontal, parietal, occipital, temporal
#midsagittal view
right and left hemisphere
#basal ganglia
movement control; coordination, posture
#limbic system
emotional memory, regulation; emotions that guide that movement; thalamus = CENTER of brain
#cerebral cortex
surrounds limbic system, which surrounds basal ganglia, which surrounds thalamus
#diencephalon
first brain in evolution; powers REFLEXIVE control of behavior; thalamus, hypothalamus, mammillary bodies
#reticular formation
sleep and arousal; temperature and motor control
#pons
has motor and sensory nuclei to face
#medulla
transition of brain to spinal cord; heart rate and breathing
#cerebellum
motor coordination and learning; underneath occiptal lobe
#meninges
brain wrappings; CONNECTIVE TISSUE that covers the brain
#dura mater
topmost layer of brain; tough hard protective
#subdural space
right under dura mater
#in between dura mater and pia mater is
CSF (made by ependymal cells); fluid flows inside to outside
#arachnoid membrane
bottom of subdural space;
#subarachnoid space
under arachnoid membrane and above pia mater; BLOOD VESSELS run here, full of CSF
#pia mater
pia = soft, soft mother, keeps brain moist right above the artery and brain surface
#cerebral ventricles
make CSF (cerebrospinal fluid) to surround and cushion brain
#cerebral cortex layers
neocortex; 6 layers, white matter at top - myelin
#pachygyria
only 3 cortical layers; have profound mental retardation
#Computerized axial tomography (CT)
DENSITY; X-ray absorption shows tissue density; denser = whiter; ONLY STRUCTURE
#what is between the bone and brain, denser than brain, not as dense as bone?
blood
#Magnetic Resonance Imaging (MRI)
strong magnets cause protons in brain tissue to line up parallel
pulse of radio waves knocks protons over
protons reconfigure, emit radio waves that differ by tissue density
ONLY STRUCTURE *white areas = abnormal
#Positron Emission Tomography (PET)
brain activity; use radioactive chemicals in bloodstream and maps destinations by emissions (shows activity) ; which regions contribute to specific functions; functional CT
#Functional MRI (fMRI)
METABOLIC ACTIVITY; detect brain metabolism changes, like oxygen use; can show how networks of structures collab; FUNCTIONAL activity of brain (super useful)
#nucleus
DNA in chromosomes, mRNA transcribe from DNA, gene expression
#rough ER
membranes with ribosomes, site of protein synthesis
#smooth ER
regulate cytoplasm
Golgi - stacks of flat membrane compartment packaging products for shipment
#neuron membrane
lipid bilayer surrounds cell and separates cytoplasm from ECM; charge separator
#instrinsic proteins
receptors, ion channels; gives properties for signaling
#microtubules
spirals of tubulin; tracks for movement within neuron; railroad tracks (STATIONARY)
#neurofilaments
static support structures
#microfilaments
associated w/cell membrane; double helix actin
#anterograde transport (what protein?)
kinesin is the enabling protein that allows material to move from soma to terminals along microtubules; MOST MOLECULES are using kinesin
#retrograde transport (what protein?)
dynein enables material from terminals to soma along microtubules
#vesicles have
neurotransmitters
#neuron cytoskeleton
#larger axon characteristics
more complexity, more distance, faster signal
#sequence of signals
synapse to synaptic cleft to neuronal membrane to ion channel
#electrostatic pressure
causes ions to flow to oppositely charged areas (electrical gradient)
#resting potential
selectively permeable to K+; at rest K+ ions move into negative inside and build up, will diffuse out along concentration gradient (-60 mV)
#sodium potassium pump
pumps Na+ out and K+ in to maintain resting potential; uses 40% of your brain's energy; if fails, brain dies
#graded potentials in dendrites
doors open to Na+, rush inside, door closes
#depolarizing response
positive into the negative cell
#hyperpolarizing response
adding negative into the negative cell
#when membrane reaches threshold
triggers action potential; inside cell becomes briefly positive