1. Traumatic Brain Injury and Strokes
Concussion- alteration in brain function, usually temporarily
Contusion- bruising of brain, permanent neurological damage
Hemorrhage- bleeding in ruptured vessels in subdural or subarachnoid spaces
Cerebral edema- swelling of brain
Cerebrovascular Accidents (CVAs or Strokes)- blood circulation to brain is blocked, brain tissue dies
Most common cause= blockage of cerebral artery by blood clot, other causes= compression of brain tissue by hemorrhage, edema, narrowing of brain vessels by atherosclerosis (plaque)

2. Degenerative Brain Disorders
Alzheimer’s- plaque litters brain between neurons & neuron fibers tangle
Disrupts transport mechanisms, cells die, brain shrinks
Most vulnerable= hippocampus & basal forebrain- thinking & memory
Symptoms: memory loss, short attention span, disorientation, language loss, moodiness, confusion, and hallucinations
Parkinson’s- degeneration of dopamine-releasing neurons of substantia nigra
Deprives basal nuclei of dopamine, become overactive
Symptoms: tremor, bent-walking posture, shuffling gait, stiff facial expression, slow initiating/executing movement
Huntington’s- fatal hereditary disorder
Protein accumulates in brain cells & tissue dies massive degeneration basal nuclei & later of cerebral cortex
Symptoms: wild, jerky, flapping involuntary movements, later- mental deterioration

3. Spinal Cord Trauma Paralysis- loss of motor function
Flaccid paralysis- damage to ventral root/horn cells, nerve impulses no longer reach skeletal muscles, muscles atrophy
Spastic paralysis- damage to upper motor neurons of primary motor cortex, skeletal muscle movement not under control, but muscles remain healthy
Transection of spinal cord at any level results in total motor & sensory loss in all body regions inferior to site of damage
Paraplegia, Quadraplegia, Hemiplegia (1 side of body)
Spinal shock- period of functional loss that follows a traumatic injury to spinal cord
Neural function usually returns within a few hours following the injury

4. Spinal Cord Disorders
Poliomyelitis (Polio)- inflammation of spinal cord from destruction of ventral horn motor neurons by poliovirus
Early symptoms: fever, headache, muscle pain and weakness, loss of certain somatic reflexes
Later: paralysis and muscle atrophy
Vaccines have nearly eliminated this disease
Amyotrophic Lateral Sclerosis (ALS or Lou Gehrig’s Disease)- progressive destruction of ventral horn motor neurons and fibers of pyramidal tract
Loose ability to speak, swallow and breathe, death typically occurs in 5yrs of onset

5. Drugs and Drug Abuse
Drug- any substance other than food that changes the structure or function of the body
ALL drugs have the potential to do harm if they are used improperly
Drug abuse- using any drug in a way that most doctors would not approve

6. Stimulants vs Depressants
Stimulants- increase actions regulated by the nervous system (sympathetic, CNS, or both; especially RAS)
Effects- feel energetic but when it wears off brains neurotransmitters are depleted, leads to feeling fatigued and depressed
Long tem can cause circulatory problems, hallucinations, and psychological problems
Depressants- “depress” (slow down) actions regulated by the nervous system (many different parts of brain, especially RAS)
Some prevent nerve cells from starting an action potential
Depressant + alcohol can cause death because nervous system is depressed to the point breathing stops
Hallucinogens (LSD, XTC, Mescaline, )- interfere with sensory blocking of RAS

7. Drugs Associated with Pleasure Centers
Many pleasure systems in the limbic system
Addiction- uncontrollable craving for more of a drug
Cocaine- sudden release of dopamine
Causes intense feelings of pleasure and satisfaction, it also depletes the brain of stored dopamine, causing depression shortly after use and psychological dependence
Very powerful stimulant- can cause heart attack
Crack- potent and dangerous form of cocaine, addictive after only a few uses
Opiates- pain-killing drugs produced from opium poppy- mimic endorphins
1st use produces strong feelings of satisfaction and security, but the body gets used to the higher levels of endorphins quickly and cannot do without
Depressants
Intravenous drug use

8. Marijuana and Alcohol Marijuana- Tetrahydrocannabinol (THC) Alcohol
Most widely abused drug
Can produce temporary feeling of euphoria and disorientation
Bad for lungs
Long-term use can cause loss of memory, inability to concentrate and reduced levels of testosterone in males
Alcohol
Can produce feelings of relaxation and confidence, but even a small amount slows reflexes, disrupts coordination and impairs judgment
One of most dangerous and abused depressants
Alcohol abuse costs the US at least $150 billion per year!
Cirrhosis- scar tissue in liver