Phys 2 Final (EEG, sleep, CSF, BBB, Neural plasticity)

T/F Electroencephalogram (EEG) readings are from millions of neurons firing synchronously

TRUE

What are EEGs used for?

evaluation/diagnosis of epilepsy, sleep disorders, understanding overall brain activity

_______ waves are typical during calm, resting, and awake states and are ______ frequency and _____ voltage

Alpha; high; low

_______ waves are typical during adult activation of frontal and parietal lobes (thinking, learning, processing) and are ______ frequency and _____ voltage

Beta; highest, low

_______ waves are typical during emotional stress and are ______ frequency and _____ voltage

Theta; low; higher

_______ waves are typical during deep slow-wave sleep and are ______ frequency and _____ voltage

Delta; very low; very high

What is a state of unconsciousness that a person can be aroused from?

sleep

What is a state of unconsciousness that a person cannot be aroused from?

coma

What are the two types of sleep?

REM and slow-wave

Which type of sleep is characterized by bouts of increased brain activity (beta waves) that occur every 90 minutes and last 5-30 min, associated w/ dreams, and is more difficult to wake from?

REM

REM atonia is ____________ due to motor neuron hyperpolarization

temporary paralysis

What type of sleep is characterized by longer bouts that last about 1 hr, decreased brain activity, and is when recovery and repair occur in the body?

slow-wave

Melatonin is released by the _________ via stimulation of __________ of the hypothalamus --> 'light-dark cycle'

Pineal gland; suprachiasmatic nucleus (SCN)

In a ______ environment, the SCN deactivates the paraventricular nucleus via GABA --> inhibits sympathetic NS --> decreases superior cervical ganglion activity --> _______ pineal galnd activity --> ______ melatonin release

light; decreases, decreased

When does peak secretion of melatonin occur? When does secretion begin to reduce?

children pre-puberty

- age 25

What is released by the Raphe nuclei?

serotonin

If the formation of serotonin is blocked, it results in ______ and if the raphie nuclei are stimulated, this results in ______

wakefulness; sleep

What is sleep deprivation associated with?

poor cognition, physical performance, and overall health

What is characterized by pauses in breathing or insufficient breathing during sleep?

sleep apnea

What is the most common type of sleep apnea that is due to collapsible airways of the pharynx (URTI, obesity, teeth/jaw dysfunction)?

Obstructive sleep apnea

What type of sleep apnea is due to imbalanced respiratory control centers (Medulla --> nucleus of solitary tract)?

Central sleep apnea

What is the inability to regulate sleep wake cycle due to degeneration og Orexin releaseing neurons from the lateral hypothalamus?

Narcolepsy

What are 5 features of narcolepsy?

daily sleepiness, cataplexy, inability to move at start/end of sleep, vivid hallucinations, fragmented sleep

Focal seizures are _______ and _________, whereas, generalized seizures are _______ and _______

small & localized; diffuse & bilateral

What is the loss of consciousness that affects all areas of the brain, and alters tonic and clonic?

generalized tonic-clonic (grand mal) seizure

What are features of tonic-clonic seizures?

biting of tongue, possible cyanosis, loss of control of bowel & bladder, lasts 3-4 min, state of confusion afterwards

T/F the cortex (gray matter) receives 4 times as much blood flow as white matter

TRUE

What is cerebral blood flow primarily determined by? What else can determine cerebral blood flow?

tissue metabolism

- sympathetic innervation

_______ metabolism = ______ CO2 concentration --> _______ localized blood flow

increased

T/F tissue metabolism is impaired or absent in 30% of concussions

FALSE

- sympathetic innervation

What is it called when cerebral blood flow is tightly controlled, even with fluctuating blood pressures and is controlled by larger cerebral arteries to protect smaller vessels from rupture?

autoregulation

What is the interruption of cerebral blood flow and can be either ischemic or hemorrhagic? What deficits are possible?

Stroke

- motor and sensory deficits

when dyes are injected in the venous circulation, all organs are stained except what? What about when dyes were injected into CSF?

brain and spinal cord

- stained brain and spinal cord

What are exceptions of BBB?

some areas of hypothalamus and pituitary (water balance and neuroendocrine), pineal gland (melatonin), area postrema (toxins stimulate vomiting centers and Angiotensin II increases BP)

What are the functions of the BBB?

protect brain from pathogens, toxins, immune factors, antibodies, etc

How is the BBB different from normal capillary endothelial cells in the body?

continuous tight junctions (maintained by astrocytes) and NO transendothelial pathways

What are uncharged molecules that readily diffuse? Examples?

hydrophobic/lipid soluble

ex) lipids, oxygen, CO2, alcohol, anesthetics

What are charged molecules that are blocked from diffusion and must be transported?

hydrophillic

What disease can break down the BBB?

MS, stroke, tumors, encephalitis

What are functions of CSF?

Protection

- minimizes mvnt of brain within cranium

Lymphatics

- carry proteins and metabolic wastes from brain tissue through perivascular spaces into large cerebral veins via arachnoid granulations

If a tumor is blocking normal CSF fluid what can happen?

accumulation of CSF in ventricle or subarachnoid space --> hydrocephalus

T/F While awake the brain accouts from 50% of the body's total metabolism

FALSE

- 15-25% of body's total metabolism

What is a special requirement for brain metabolism where a lack of this may cause unconsciousness within 5-10 seconds?

oxygen

What looks at brain activity by examining changes in blood flow?

Functional magnetic resonance imaging (fMRI)

What measures rates through a radioactive glucose injection? What is this useful for?

PET scans

- brain activity, location of infarction, location and therapy responsiveness in tumors

T/F PNS regeneration is much better than CNS

TRUE

When PNS is damaged what happens after 1-2 wks? After that?

Wallerian degeneration is complete

- Schwann cells proliferate and release trophic factors

What is a temporary mild compression/traction injury where the axon is still intact?

neuropraxia

What is a moderately severe injury where the axon is severed but endo, peri, and epineurium are intact and regeneration is expected 1mm/day?

axonotmesis

What is a severe injury where the nerve is completely severed?

neurotmesis

What restricts repair when there is damage to CNS?

glial cells

Characteristics of CNS damage?

Wallerian degeneration occurs, NO trophic factors are released, NO connections are re-established

T/F CNS neurons are completely incapable of regenerating

FALSE

- that can regenerate

What is the brains abilty to change and adapt its structure and fxn throughout life?

neuroplasticity

Is the CNS plastic?

YES

Only _______ layout of NS is predetermined; later stages of development are when neuronal connections are made and matched to environment, thus making ____________ crucial for neuroplasticity

general; early development

Once connections are made, there is a more ________ amount of plasticity but the ability to adjust synaptic _______ continues

limited; strength

What does plasticity rely on?

nerve growth factor

Neurons are ______ in early development, meaning appropriate interaction and neurotrophic factors are needed

overproduced

About how many newborn neurons die?

half

What areas mature first? Last?

motor, somatosensory, visual

- association

What does maturation during adolescence and early adulthood focus on?

myelinogenesis

balance of excitatory vs inhibitory fxn

- glutamatergic predominates

- GABA under construction

vulnerability to impulsive behavior due to lack of fully established inhibitory balance

What is associated with adolescent and young adult binge drinking?

reduced inhibitory control of brain activity vs light/non-drinkers

Susceptibility to impulsive/quick reward descision

deficits in working memory