Human Physiology Brain Functions

What are the language centers of the brain and their functions?

Broca’s area in the frontal lobe for motor speaking; Wernicke’s area in the junction of the temporal, parietal, and occipital lobes for language comprehension.

On which side of the brain are the language centers typically located?

The left side of the brain for 70% to 95% of people.

Left hemisphere language specialization

What does brain lateralization mean?

It refers to the differences in hemisphere function, partially linked to handedness.

How do the two hemispheres of the brain communicate?

They communicate through the fibers of the corpus callosum.

What are the four stages of sleep?

Awake, REM sleep, non-REM sleep; frequency decreases as stages progress.

What happens during REM sleep regarding muscle movement and brain activity?

In REM sleep, brain, heart, and respiration are active, but muscles are paralyzed.

What are characteristics of dreams during REM sleep?

REM dreams are relatively long, primarily visual, somewhat emotional, and usually not connected to real life

Sensation: vivid, internally generated

Thought: vivid, illogical, bizarre

Movement: muscle paralysis, movement commanded by the brain but not carried out often

Rapid eye movement: often

The function of REM sleep is not well understood, several theories have been proposed such as consolidation of procedural memory and spatial memory, and stimulation for proper nervous system development

What stimulates the reticular activating system (RAS) and what is its effect?

Stimulation of the RAS center in a slumbering animal arouses the animal; conversely, destruction of the center causes the animal to go into a permanent coma

During REM sleep, which is when dreaming occurs, the activity in the RAS increases to levels similar to those seen during wakefulness

What role does Benadryl play in causing drowsiness?

Benadryl inhibits histamine-releasing neurons of the RAS by crossing the blood-brain barrier.

What are the two forms of memory?

Declarative (explicit) memory

  i.     From hippocampus to many areas of the association cortex

   ii.     Recall requires conscious attention

  iii.     depends on higher-level thinking skills such as inference, comparison, and evaluation

   iv.     memories can be reported verbally

    Procedural (implicit) memory

     i.     Widely distributed to basal nuclei, cerebellum, premotor cortex

   ii.     Recall is automatic and does not require conscious attention

     iii.     Acquired slowly through repetition

   iv.     Includes motor skills and rules and procedures

    v.     Procedural memories can be demonstrated

What is the function of the hippocampus?

Essential for forming new declarative memories.

Define dementia and its two most common types.

  Progressive loss of intellectual function, including memory, thinking, orientation, comprehension, calculation, learning capacity, language and judgement. Consciousness is not clouded

  2 most common causes/types: Alzheimer’s disease, dementia with Lewy bodies.

What are the key pathological signs of Alzheimer's disease?

-Abnormal processing of protein APP, generating amyloid beta (Aβ), Aβ aggregation forms polymers and plaques outside of cells.

-Abnormal modification (hyperphosphorylation) of tau proteins separate microtubules and form neurofibrillary tangle in the cells, disabling the transport system and destroying the neuron.

-In both cases, normal proteins go through abnormal modification or processing.

-These are diagnostic signs of, but may not be the cause of AD

-The misfolding and clumping of alpha-synuclein protein in dopaminergic neurons (neurons that produce and release dopamine) in the substantia nigra is a hallmark of PD.

-These toxic protein aggregates, known as Lewy bodies, disrupt normal cell function and lead to neuronal death

 --Amyloid plaque (extracellular, by amyloid beta), neurofibrillary tangle (intracellular, by tau protein)

What is the primary brain region affected in Parkinson's disease?

The substantia nigra, where dopamine-utilizing neurons are lost.

What is a typical symptom of Parkinson's disease?

Tremor, most evident at rest.

What is the hallmark pathological feature in neurons affected by Parkinson's disease?

Accumulation of Lewy bodies formed by alpha-synuclein protein.