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Valeria Tovar Period 3 Nervous System, Major Functions of the Nervous…
Valeria Tovar Period 3
Nervous System
Definition
: The nervous system controls and coordinates all body activities and allows the body to respond to internal and external changes.
Sensory Input
: detects stimuli inside/outside the body using receptors.
Integration:
processes, interprets, and decides what to do.
Motor Output
: sends signals to muscles/glands to respond
Homeostasis
: maintains stable internal conditions
Mental activity
: thinking, memory, and emotion
Coordination of movement
Definition
: Structural and functional divisions of the NS.
Structural Divisions
Central Nervous System (CNS)
Brain
Spinal cord
Peripheral Nervous System (PNS)
:
Cranial nerves
Spinal nerves
Ganglia
Functional Divisions (PNS)
Somatic Nervous System
: voluntary; skeletal muscles
Autonomic Nervous System (ANS)
: involuntary; smooth & cardiac muscle, glands
Sympathetic
: fight or flight
Parasympathetic
: rest and digest
Enteric
: controls GI tract
Definition:
Cells that make up nervous tissue
Neurons (Structure & Function)
Cell Body (soma):
contains nucleus
Dendrites
: receive signals
Axon
: sends impulses away from cell body
Myelin sheath
: speeds conduction
Node of Ranvier
: gaps allowing saltatory conductions
Neuroglia (Glial Cells)
CNS
:
Astrocytes
: supports, blood brain barrier
Oligodendrocytes:
form myelin in CNS
Microglia
: immune defense
PNS
:
Schwann cells
: form myelin in PNS
Satellite cells
: support neuron cell bodies
By Structure
Unipolar
Bipolar
Multipolar
By Function
Sensory (afferent)
Motor (efferent)
Interneurons (association neurons)
Definition
: Protective layers around nerves.
Endoneurium
: surrounds each axon
Perineurium
: surrounds fascicles
Epineurium
: outer covering of the entire nerve
Cerebrum
Higher thinking, memory, voluntary movements.
Lobes
Frontal: reasoning, movement
Parietal: sensory info
Temporal: hearing, memory
Occipital: vision
Diencephalon
Thalamus: relay station
Hypothalamus: homeostasis, hormones
Pineal gland: melatonin
Brainstem
Midbrain: reflexes
Pons: breathing regulation
Medulla oblongata: vital functions
Cerebellum
Coordination and balance
Structure
: cervical, thoracic, lumbar, sacral regions
Functions
:
Conduct impulses to/from brain
Reflex center
Gray Matter:
cell bodies
White matter
: myelinated axons
Definition
: Electrical signal used by neurons to send information.
Steps
:
Resting Potential
Threshold
Depolarization (Na+ enters)
Repolarization (K+ leaves)
Hyperpolarization
Return to resting potential
Saltatory conduction
Impulse "jumps" between nodes faster
Definition
: Nerves that originate from the brain
Olfactory: smell
Optic: Vision
Oculomotor: moves eyes
Trochlear: moves eyes
Trigeminal: face sensation
Abducens: moves eye
Facial: facial expressions
Vestibulocochlear: hearing and balance
Glossopharyngeal: taste, swallowing
Vagus: organs (parasympathetic)
Accessory: neck muscles
Hypoglossal:tongue movemnet
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
Definition: Chemical messengers between neurons.
Acetylcholine — muscle contraction
Dopamine — reward, movement
Serotonin — mood regulation
Norepinephrine — alertness
GABA — inhibitory
Glutamate — excitatory
Endorphins — pain relief
Sympathetic (Fight or Flight)
Increases HR
Dilates pupils
Slows digestion
Releases adrenaline
Parasympathetic (Rest & Digest)
Slows HR
Constricts pupils
Stimulates digestion
Restores homeostasis
Compare:
Both involuntary
Both regulate organs
Both use two-neuron pathways
Definition: Rapid, automatic response without conscious thought.
Major Parts:
Receptor
Sensory neuron
Integration center (spinal cord)
Motor neuron
Effector (muscle or gland)
Multiple sclerosis – myelin destruction
Parkinson’s disease – dopamine deficiency
Alzheimer’s – memory loss, brain degeneration
Epilepsy – abnormal brain electrical activity
Stroke – interrupted blood flow to brain
Meningitis – infection of meninges
Cocaine – dopamine; overstimulation
Heroin – mimics endorphins; pain relief + euphoria
Alcohol – enhances GABA; slows brain function
Marijuana (THC) – alters memory, coordination
Methamphetamine – releases huge dopamine amounts
Ecstasy (MDMA) – dopamine + serotonin surges
Major Functions of the Nervous System
Major Divisions & Subdivisions of the Nervous System
Tissues: Neurons & Neuroglia
Classification of Neurons
Connective Tissue Coverings
Major Parts & Functions of the Brain
Major Parts & Functions of the Spinal Cord
Action Potential & Nerve Impulse
Cranial Nerves
Spinal Nerves
Neurotransmitters
Compare & Contrast the Autonomic Nervous System
Reflex Arc
Nervous System Disorders/Diseases
Drugs of Abuse (Mouse Party)