Overview of the Nervous System and Its Functions

Central Nervous System (CNS)

Includes the brain and spinal cord.

Peripheral Nervous System (PNS)

Nerves connecting CNS to body organs.

Autonomic Nervous System

Controls internal organs and self-regulating functions.

Sensory Neurons

Afferent nerves bringing information to CNS.

Internuncial Neurons

Neurons located within the CNS.

Motor Neurons

Efferent nerves sending information away from CNS.

Membrane Excitability

Neurons activated by ion movement across membranes.

Action Potential

Brief positive charge inside neuron when activated.

Simple Reflex Actions

Quick responses without brain involvement, direct pathways.

Complex Reflex Actions

Involuntary responses needing integration in CNS.

Synapse

Space between axon and dendrite of neurons.

Neurotransmitters

Chemicals released at synapses affecting transmission speed.

Knee-Jerk Reflex

Example of a simple reflex action.

Withdrawal Reflex

Response to harmful stimuli, involves sensory and motor neurons.

Crossed Extensor Reflex

Involves multiple muscles for balance during withdrawal.

Blink Reflex

Rapid eye closure to protect from approaching objects.

Cranial Nerves

12 pairs of nerves originating from the brain.

Stimulants

Substances like cocaine that speed up reactions.

Depressants

Substances like alcohol that slow down reactions.

Neurotoxins

Toxins causing muscle contraction or paralysis.

Reflex Arc

Pathway of nerve impulses in reflex actions.

Cranial nerves

Connect brain to eyes, ears, tongue, nose, skin.

Spinal Nerves

31 pairs; motor and sensory functions.

Motor Nerves

Permit movement by transmitting signals.

Sensory Nerves

Perceive stimuli from the environment.

Autonomic Nervous System

Involuntary control of breathing, heartbeat, digestion.

Peripheral Nervous System

Includes autonomic and somatic nervous systems.

Sympathetic Division

Prepares body for 'fight or flight' response.

Parasympathetic Division

Promotes 'rest and digest' functions.

Vagus Nerve

Extends from brain to upper abdomen.

Pelvic Nerves

Branches to lower abdominal and pelvic organs.

Cerebrum

Controls sensory and motor activities; divided into lobes.

Frontal Lobe

Associated with emotions, personality, and intellect.

Occipital Lobe

Located at back; responsible for vision.

Parietal Lobe

Located at the top; processes sensory information.

Temporal Lobe

Involved in hearing and memory functions.

Cerebellum

Coordinates muscle movement and sensory impulses.

Medulla Oblongata

Controls heart, lungs, and stomach functions.

Pons

Regulates breathing, chewing, and saliva secretion.

Midbrain

Controls reflex movements and pupil dilation.

Thalamus

Relay station for sensory and motor impulses.

Hypothalamus

Regulates autonomic functions and homeostasis.

Meninges

Coverings of the brain and spinal cord.

Pia Mater

Inner layer containing nerve tissue of meninges.

Arachnoid

Middle layer of delicate, lacelike membranes.

Dura Mater

Outer layer protecting CNS from bony surfaces.

Ventricles

Cavities in the brain facilitating nerve travel.

Central Canal

Connects spinal cord to inferior brain ventricle.

Subarachnoid Space

Area between arachnoid and pia mater layers.

Cerebrospinal Fluid (CSF)

Watery cushion providing CNS protection and nutrient transport.

CSF Formation Rate

450 ml (15 oz) produced daily in ventricles.

Arteriography

Procedure using dye to detect vascular abnormalities.

Glasgow Coma Scale (GCS)

Tool assessing level of unconsciousness via responses.

Computerized Axial Tomography (CAT)

3D imaging technique using x-rays of the brain.

Electroencephalography (EEG)

Measures brain's electrical signals for abnormalities.

Electromyography (EMG)

Tests electrical activity in peripheral muscles.

Genetic Testing

Identifies genes linked to neurological disorders.

Lumbar Puncture

Procedure to extract CSF for diagnostic purposes.

Magnetic Resonance Imaging (MRI)

Uses magnets for detailed brain and spinal images.

Myelography

Imaging spinal cord using contrast and fluoroscopy.

Position Emission Tomography (PET) Scan

Records metabolic activity in the body using tracers.

Ultrasound Imaging

Uses sound waves for internal body imaging.

Neurosonography

Analyzes brain blood flow to diagnose conditions.

X-rays

Imaging technique for viewing bones and organs.

Alzheimer's Disease

Progressive brain disease causing memory and behavior loss.

Amyotrophic Lateral Sclerosis (ALS)

Fatal disease causing motor neuron degeneration.

Bell's Palsy

Facial nerve disorder causing temporary paralysis.

Cerebral Palsy

Nonprogressive brain injury occurs during fetal development, which affects brain and muscle development

Dementia

Cognitive decline affecting memory and daily functions.

Encephalitis

Severe brain inflammation causing nerve cell destruction.

symptoms of encephalitis

Sudden fever, headache, neck stiffness, vomiting.

Causes of Encephalitis

Viruses from mosquitoes, ticks, or infections like herpes.

Epilepsy

Seizure disorder affecting 3 million adults in the US.

Seizure Characteristics

Abnormal electrical impulses causing convulsions and loss of control.

Essential Tremor

Common movement disorder causing involuntary shaking.

Tremor Triggers

Worsens with movement; common in those over 40.

Guillain-Barré Syndrome

Autoimmune disorder attacking the nervous system.

GBS Symptoms

Nerve inflammation leading to muscle weakness and paralysis.

Headache Classification

Primary headaches from pain-sensitive structures; secondary from diseases.

Migraine Headache

Severe throbbing pain often with visual disturbances.

Migraine Triggers

Diet, sleep, activity, lights, and psychological factors.

Primary Headaches

Caused by lifestyle factors affecting pain-sensitive areas.

Secondary Headaches

Result from underlying diseases or conditions.

Age Factor in Essential Tremor

Commonly occurs in individuals aged 40 and older.

Meningitis

Inflammation of brain and spinal cord meninges.

Viral Meningitis

Most common, benign form of meningitis.

Bacterial Meningitis

Severe, untreated mortality rate 70-100%.

Fungal Meningitis

Rare, spreads from blood to spinal cord.

Multiple Sclerosis

Myelinating disease affecting young adults' CNS.

Neuralgia

Severe nerve pain along affected nerves.

Paralysis

Loss of voluntary function, temporary or permanent.

Spastic Paralysis

Caused by upper motor neuron damage.

Flaccid Paralysis

Caused by lower motor neuron damage.

Hemiplegia

One-sided paralysis from brain damage.

Paraplegia

Loss of function in lower extremities.

Quadriplegia

Permanent paralysis affecting all body systems.

Parkinson's Disease

Progressive disease is characterized by muscle rigidity and tremors. Symptoms include muscle rigidity, hand tremors, masklike facial expressions, peculiar gait, drooling, and a bowed head.

Reye's Syndrome

Acute childhood illness can lead to a buildup of fat in the liver and higher pressure in the brain.

Sciatica

Inflammation of the sciatic nerve, unilateral pain.

Spina Bifida

Incomplete closure of vertebrae during development.