Vocab Review Exam 3

hypoxia

drop in oxygen to the brain

ischemia

decrease in blood flow to the brain

stroke

Blood flow to the brain is disrupted and results in neuronal death

voltage

electrical potential difference created by separate charges

current

the movement of electrical charges, moving ions across membranes, flow of electrical charge

resistance

anything that opposes the movement of charge, hinderance

leakage channels

remains open and allows ions to move continuously across the membrane

voltage gated channels

along axons, allow action potentials to be generated and propagated

mechanical channel

open when the membrane is physically deformed (touch, pressure, vibration, sensory, hearing, balance)

dendrites

receptive region, process/projection, receives input and sends impulses toward the cell body

soma

aka cell body, receptive region

axon hillock

adds up input, reaches the threshold and fires

axon

sends impulses away from cell body, conducting region, can be short or long

axon terminal

transmit chemical signals to the next neuron, makes connections with other nerve cells

resting membrane potential

typical neuron has an RMP of about -70mV, inside of the cell is electrically negative

ions are distributed unequally across the membrane

membrane more permeable to some ions compared to others

Na+ moves in, K+ moves out

depolarization

A change in membrane potential from rest to a more positive value due to the INFLUX of positively charged ions, neuron more likely to fire

hyperpolarization

A change in membrane potential from rest to a more negative value due to the EFFLUX of positively charged ions, the neuron is less likely to fire

repolarization

returning to rest

following the peak o fan action potential, the membrane potential drops back down toward resting value, restoring polarity

excitatory synaspes

makes the neuron more likely to initiate an action potential

NT binds to ion channel → Na+ moves in → depol.

inhibitory synapses

Makes the neuron less likely to initiate an action potential

NT binds to ion channels → Cl- moves in or K+ moves out → hyperpol.

temporal summation

individual channels can be activated repeatedly over a short period, to cause a greater change in postsynaptic potential

spatial summation

Channels that are physically close together can be opened simultaneously to cause a greater change in postsynaptic potential

large # of presynaptic neurons

saltatory conduction

the action potential leaps from node to node as it propagates fown a myelinated axon

astrocytes

CNS, provide nutrients to neurons; regulation of cerebral blood flow; maintain extracellular fluid; highly branched; tissue repair; regulates endothelial cells that form the BBB

oligodendrocytes

CNS, myelin production; immune functions; metabolic support; branched and wrapped around axons

ependymal cells

CNS, CSF production; neurogenesis

microglia

resident macrophages; immune support, remove old/dead neurons

schwann cells

PNS; myelin production; regeneration of peripheral axons; nerve development; extracellular matrix

satellite cells

PNS; surrounding neuronal cell bodies; nutrient supply; protective

diverging

One input, many outputs. Amplifies signals across multiple motor or sensory pathways

converging

many inputs, one output. Concentrates incoming signals to elicit a single common effect

parallel after discharge

Parallel pathways converge on output cells. Creates bursts of impulses involved in complex mental tasks

reverberating

signal feedback loop. Controls rhythmic activity such as breathing and walking

neuronal pool

neural circuit; integrates incoming information from various sources to coordinate a specific output

ventral root

Carries motor axons from the spinal cord to the spinal nerve. The nerve splits into 2 roots that enter the dorsal and ventral aspects of the spinal cord

dorsal root

carries sensory axons from the spinal nerve into the spinal cord

white matter

The tissue making up myelinated axons. The high lipid content gives it a white appearance

dorsal root ganglia

a peripheral swelling that contains the bodies of sensory neurons

association fibers

connect different areas of the cerebral cortex within the same hemisphere, allowing communication between regions of the same side of the brain

commissural fibers

connect left and right hemispheres, allowing information to pass between

projection fibers

connect the cerebral cortex with lower regions of the brain and spinal cord, carrying both ascending information and descending motor commands

corpus callosum

largest bundle of commissural fibers, connecting the two hemispheres

corona radiata

ran-shaped arrangement of fibers spreading toward or away from the cerebral cortex

internal capsule

compact bundle of projection fibers that carries information between the cortex and deeper CNS structures

medulla oblongata

links brain and spinal cord

inferior portion of the brainstem, contains 2 pyramids (conscious regulation of skeletal muscle contractions), 2 rounded olives (involved in balance, coordination)

functions as a relay station for ascending afferent and descending efferent motor tracts between the spinal cord and the brain

pons

superior to the medulla oblongata

bridge-like structure that links different parts of the brain

relay station from medulla oblongata to higher cortical structures of the brain

midbrain

regulates visual and auditory reflexes

serves as the nerve pathway of the cerebral hemispheres and contains auditory and visual centers

thalamus

acts as a relay station for signals incoming from many parts of the brain, transmitting them to the cerebral cortex. Involved in mood and emotional regulation

medial geniculate: receives sensory information for the auditory sensory nerves

lateral geniculate: receives sensory information from the eyes

epithalamus

superior and posterior to the thalamus

associated with the pineal gland and melatonin

primary motor cortex

located in precentral gyrus of the frontal lobe

inititating signals that produces voluntary skeletal muscle movements, conscious motor control, controlater communication (R controls L)

premotor cortex

helps plan and coordinate skilled movement, organizes the activity of multiple muscle groups before signals are sent to the primary motor cortex to initiate movement anterior to the precentral gyrus

• Coordinates several muscle groups together (playing an instrument)

broca’s area

Important for speech production and regions involved in processing and recognizing odors

motor speech, thoughts become words

damage = can’t talk

primary somatosensory cortex

Receives and processes sensory info from skin, visceral muscles, joints, like touch, pain, temp

Allows for spatial discrimination; can identify where a stimulus is coming from

somatosensory association cortex

integrates incoming sensory information with previous experiences, allowing us to recognize and interpret what we feel

gives sensory input understanding

damage= can’t give objects understanding without feeling it

primary visual cortex

receives visual information originating from the retina of the eye

Processes basic visual features like location, contrast

visual association area

interprets visual info by comparing it with memories from previous visual experiences, recognizes faces and objects

damage= see but not understand

primary auditory cortex

responsible for hearing, processes basic sound characteristics like pitch and loudness

damage= hear but can’t understand

auditory association area

interpret and recognize complex sounds like recognizing a familiar voice