AP ch 12 part c

Amygdala--recognizes angry or fearful facial expressions, assesses danger, and elicits the fear response

Cingulate gyrus--plays a role in expressing emotions via gestures, and resolves mental conflict

The limbic system interacts with the prefrontal lobes, therefore;

-We can react emotionally to things we consciously understand to be happening

-We are consciously aware of emotional richness in our lives

Hippocampus and amygdala--play a role in memory

RAS (reticuar activating system)

-sends impulses to the cerbral cortex to keep it conscious and alert

-Filters out repetitive and weak stimuli (99% of all stimuli)

-Severe injury results in permanent unconsciousness (coma)

Motor Function

• -helps control coarse limb movements
• -Vasomotor
• -Cardiac
• -Respiratory

-Records electrical activity that accompanies brain function

- Measures electrical potential differences between various cortical areas

-Alpha waves (8-13 Hz) --regular and rhythmic, low amplitude syncchonous waves indicating an idling brain

-Beta Waves (14-30 Hz)--rhythmic, less regular waves occurring when mentally alert

-Theta waves (4-7 Hz) --more irregular, common in children and uncommon in adults

-Delta waves (4Hz or less) -high-amplitutude waves seen in deep sleep and when reticular activating system is damped or during anesthesia, may indicate brain damage

-A victim of epilepsy may lose consciousness, fall stiffly and have uncontrollable jerking

-Epilepsy is not associated with intellectual impairments

-occurs in 1% of the population

Seizures

-absence seizures or petit mal--mild seizures seen in young children where the expressio goes blank

-Tonic-clonic (grand mal) siezures- victim loses consciusness bites toungue

Clinically defined on a continuum that grades behavior in response to stimuli

• -Alerness
• -Drownsiness (lethargy)
• -Stupor
• -Coma

Two major types of sleep (defined by EEG patters)

-Nonrapid eye movement (NREM)

-Rapid eye movement (REM)

Narcolepsy

-Lapsing abruptly into sleep from the awake state

Insomnia

-Chronic inability to obtain the amount or quality of sleep needed

Sleep apnea

-Temporary cessation of breathing during sleep

Two stages of storage

Short-term memory (STM or working memory) temprary holding of information limited to seven or eight peices of information

Long-term memory (LTM) has limitless capacity

Factors that affect transfer from STM to LTM

-Emotinal state--best if alert,motivated,suprised and aroused

-rehersal--repetition and practice

-association--tying new information with old memories

-Automatic memory--subconscious information stored in LTM

Bone--skull

Membranes--meninges

Watery cushion --cerebrospinal fluid

Blood-brain barrier

Strongest meninx

Two layers of fibrous connective tissue (around the brain) seperate to form dural sinuses

Middle layer with weblike extensions

seperated from the dura mater by the subdural space

Subarachnoid space contains CSF and blood vessels

Anachnoid villi protrude into the superior sagittal sinus and permit CSF reabsorption

Layer of delicate vascularized connective tissue that clings tightly to the brain

Functions

-Gives buoyancy to the CNS organs

-Protects the CNS from blows and other trauma

-Nourishes the brain and carries chemical signals

-Produce CSF at a constant rate

-Hang from the roof of each ventricle

-Clusters of capillaries enclosed by pia mater and a layer of ependymal cells

-Ependymal cells use ion pumps to control the composition of the CSF and help cleanse CSF by removing wastes

- Helps maintain a stable environment for the brain

- Separates neurons from some bloodvorne substances

Traumatic brain injuries

-Concussion--temporary alteration in function

-contusion--permanent damage

-subdural or suarachnoid hemorrhage--may force brain stem through the foramen magnum, resulting in death

-Cerebral edema--swelling of the brain associated with traumatic head injury

Cerebrovascular accidents (CVAs)(strokes)

-Blood circulation is blocked and brain tissue dies, i.e. blockage of a cerbral artery by a blood clot

-typically leads to hemiplegia or sensory and speed deficts

-Tansient ischemic attacks (TIAs)-temporary espisodes of reversible cerebral ischemia

-Tissue plasminogen activaor (TPA) is the only approved tratment fro stroke

Degenerative brain disorders

-Alzheimer's disease (AD) a progressive degenerative disease of the brain that results in dementia

-Parkinsons disease degeneration of the dopamine releasing neurons of the substantia nigra

Hunigtons disease-a fatal hereditary disorder caused by accumulation of the protien huntingtin that leads to degeneration of the basal nuclei and cerebral cortex

Flaccid paralysis--severe damage to the vetral root or ventral horm cells

--impulses do not reach muscles, there is no volumtary or involuntary control of muscles

--muscles astrophy

Spastic Paralysis--damage to upper motor neurons of the primary motor cortex

--spinal neurons remain intact, muscles are stimulated by reflex activity

--No voluntary control of muscles

Transection

--Cross sectioning of the spinal cord at any level

--Results in total motor and sensory loss in regions inferior to the cut

--Parplegia--transection between T1 and L1

--Quadriplegia--Transection in the cervical region

-destruction of the ventral horn motor neurons by the poiovirus

-Muscles astophy

-Death may occur due to paralyss of respiratory muscles or cardiac arrest

Survivors often develop postpolio syndrome many years later, as neurons are lost

Lou Gehrigs disease

Ivolves prgressive destruction of the ventral horn motor neurons and fibers of the pyramidal tract

symptoms--loss of the ability to speak, swallow, and breathe

Death typically occurs within five years

Linked to glutamate excitotoxicity, attack by the immue system or both.