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Nervous system - Jade Mellin Period 3 - Coggle Diagram
Nervous system - Jade Mellin Period 3
Major Functions of the Nervous System
Sensory Input – receives information from environment & body
Integration – processes and interprets sensory input
Motor Output – responds by activating muscles or glands
Major Divisions & Subdivisions
Central Nervous System (CNS)
Spinal cord
Brain
Peripheral Nervous System (PNS)
Somatic Nervous System (SNS) – voluntary control of skeletal muscles
Autonomic Nervous System (ANS) – involuntary control
Sympathetic – “fight or flight”
Parasympathetic – “rest & digest”
Tissues (Structure & Function)
Neurons – transmit electrical signals
Dendrites – receive signals
Cell body – contains nucleus
Axon – sends signal
Axon terminals – release neurotransmitters
Neuroglia (glial cells) – support & protect neurons
Astrocytes – blood-brain barrier, nutrient support
Oligodendrocytes – myelinate CNS axons
Schwann cells – myelinate PNS axons
Microglia – immune defense in CNS
Ependymal cells – produce cerebrospinal fluid
Classification of Neurons
Sensory (afferent) – carry impulses to CNS
Motor (efferent) – carry impulses from CNS to muscles/glands
Interneurons – connect sensory & motor neurons in CNS
Connective Tissue Coverings
Endoneurium – surrounds individual axons
Perineurium – surrounds fascicles (bundles of axons)
Epineurium – surrounds entire nerve
Major Parts & Functions of the Brain
Cerebrum – thinking, memory, voluntary movement
Cerebellum – coordination, balance
Diencephalon
Thalamus – relay sensory info
Hypothalamus – homeostasis, hormones
Brainstem
Midbrain – visual/auditory reflexes
Pons – relay signals, breathing
Medulla oblongata – heart rate, breathing, reflexes
Major Parts & Functions of Spinal Cord
Gray matter – neuron cell bodies
White matter – myelinated axons
Functions: reflexes, transmission of nerve impulses to/from brain
Regions: cervical, thoracic, lumbar, sacral
Action Potential & Nerve Impulse
Resting potential: -70 mV, neuron ready to fire
Depolarization: sodium enters cell, becomes positive
Repolarization: potassium leaves, restores negative charge
Hyperpolarization: temporary overshoot
Propagation: impulse travels down axon
Synaptic transmission: neurotransmitters released into synapse
Cranial Nerves (12)
I – Olfactory (smell)
II – Optic (vision)
III – Oculomotor (eye movement)
IV – Trochlear (eye movement)
V – Trigeminal (face sensation)
VI – Abducens (eye movement)
VII – Facial (expression, taste)
VIII – Vestibulocochlear (hearing, balance)
IX – Glossopharyngeal (taste, swallowing)
X – Vagus (parasympathetic control)
XI – Accessory (neck muscles)
XII – Hypoglossal (tongue movement)
Spinal Nerves
31 pairs:
Cervical (8)
Thoracic (12)
Lumbar (5)
Sacral (5)
Coccygeal (1)
Mixed nerves – carry sensory & motor fibers
Compare & Contrast ANS
Sympathetic (fight or flight)
Increases heart rate, dilates pupils, inhibits digestion
Parasympathetic (rest & digest)
Decreases heart rate, constricts pupils, stimulates digestion
Reflex Arc
Sensory receptor – detects stimulus
Sensory neuron – sends signal to CNS
Integration center – interneuron in CNS
Motor neuron – sends response to effector
Effector – muscle/gland responds
Disorders/Diseases
Cerebrovascular Accident (Stroke)
Cause/Risk: blocked or burst blood vessel in the brain
Symptoms: weakness, trouble speaking, numbness
Treatment: medication, sometimes surgery, rehabilitation
Autism
Cause/Risk: differences in brain development (exact cause unknown)
Symptoms: difficulty with social interaction, repetitive behaviors, communication challenges
Treatment: therapy, educational support, sometimes medication for related symptoms
Alzheimer’s Disease
Cause/Risk: buildup of proteins in the brain, age-related
Symptoms: memory loss, confusion, trouble thinking
Treatment: medication to manage symptoms, supportive care
Spinal Cord Injury
Cause/Risk: trauma or accident damaging the spinal cord
Symptoms: loss of movement or feeling below injury
Treatment: surgery, physical therapy, rehabilitation
Meningitis
Cause/Risk: infection (bacteria or virus)
Symptoms: headache, stiff neck, fever, nausea
Treatment: antibiotics (for bacterial), supportive care
Multiple Sclerosis
Cause/Risk: immune system attacks myelin in CNS
Symptoms: numbness, weakness, vision problems, trouble walking
Treatment: medications to slow disease, therapy for symptoms
Neurotransmitters
Acetylcholine (ACh) – muscle contraction, autonomic function
Dopamine – mood, reward, movement
Serotonin – mood, sleep, appetite
Norepinephrine – alertness, stress response
GABA – inhibitory, reduces neuron activity
Glutamate – excitatory, learning & memory
Drugs of Abuse
Heroin
Neurotransmitter: Dopamine & Endorphins
How it affects the brain: Binds to opioid receptors, blocks pain, floods brain with dopamine
Mood/Effects: Euphoria, relaxation, drowsiness, addictive
Ecstasy
Neurotransmitter: Serotonin
How it affects the brain: Releases large amounts of serotonin and blocks its reuptake
Mood/Effects: Feeling happy, energetic, social, can cause confusion or anxiety
Marijuana
Neurotransmitter: Dopamine
How it affects the brain: THC binds to cannabinoid receptors, increases dopamine
Mood/Effects: Relaxed, altered perception, impaired memory
Methamphetamine (Meth)
Neurotransmitter: Dopamine
How it affects the brain: Forces massive dopamine release and blocks reuptake
-Mood/Effects: Very energetic, euphoria, high addiction risk
Alcohol
Neurotransmitter: GABA & Dopamine
How it affects the brain: Enhances GABA (inhibits brain activity), increases dopamine
Mood/Effects: Relaxed, slowed thinking, poor coordination
Cocaine
Neurotransmitter: Dopamine
How it affects the brain: Blocks dopamine reuptake, causing buildup in synapse
Mood/Effects: Alert, euphoric, addictive
LSD
Neurotransmitter: Serotonin
How it affects the brain: Binds to serotonin receptors, changes perception and mood
Mood/Effects: Hallucinations, altered thinking, mood swings