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Ashley Vargas Per. 5 Nervous System - Coggle Diagram
Ashley Vargas
Per. 5
Nervous System
Major functions of the nervous system
three overlapping functions
Integration
Motor output
Sensory input
master controlling and communicating system of body
Cells communicate via electrical and chemical signals
two principal parts
Peripheral nervous system (PNS):
Consists mainly of nerves that extend from brain and spinal cord
Central nervous system (CNS) :
Brain and spinal cord of dorsal body cavity
Classification of neurons
Structural classification
Bipolar:
two processes (one axon, 1one dendrite)
Unipolar:
one T-like process (two axons)
Multipolar:
three or more processes (1 axon, others dendrites)
Functional
Motor:
Carry impulses from CNS to effectors
Interneurons:
Lie between motor and sensory neurons
Sensory:
Transmit impulses from sensory receptors toward CNS
Major parts and functions of the brain
Cerebrum:
interprets sights, sounds and touches. It also regulates emotions, reasoning and learning
Cerebellum:
Maintains your balance, posture, coordination and fine motor skills
Brainstem:
regulates many automatic body functions
Cranial nerves
V: Trigeminal nerves:
Convey sensory impulses from various areas of face
VI: Abducens nerves:
Primarily a motor, innervating lateral rectus muscle
IV: Trochlear nerves:
Primarily motor nerve that directs eyeball
VII: Facial nerves:
Sensory function (taste) from anterior two-thirds of tongue
III: Oculomotor nerves:
raising eyelid, directing eyeball, constricting iris (parasympathetic), and
controlling lens shape
VIII: Vestibulocochlear nerves:
Formerly auditory nerve
IX: Glossopharyngeal nerves:
innervate part of tongue and pharynx for swallowing and provide
parasympathetic fibers to parotid salivary glands
X: Vagus nerves:
Only cranial nerves that extend beyond head and neck region
II: Optic nerves:
Purely sensory (visual) function
XI: Accessory nerves:
Formerly spinal accessory nerve
I : Olfactory nerves:
Sensory nerves of smell
XII: Hypoglossal nerves:
Innervate extrinsic and intrinsic muscles of tongue that contribute to swallowing
and speech
Spinal nerves
Attach to spinal cord by 31 paired roots
Each spinal cord segment is designated by paired spinal nerves that arise from it
Nerves serving upper and lower limbs emerge here
Collection of nerve roots at inferior end of vertebral canal
Part of PNS
Tissues
Arachnoid mater:
Middle layer with spiderweb-like extensions
Pia mater:
Delicate connective tissue that clings tightly to brain, following every convolution
Dura mater:
Strongest meninx
Connective Tissue Coverings
Perineurium:
coarse connective tissue that bundles fibers into fascicles
Epineurium:
tough fibrous sheath around all fascicles to form the nerve
Endoneurium:
loose connective tissue that encloses axons and their myelin sheaths
Action potential & the Nerve Impulse
Principal way neurons send signals, Involves opening of specific voltage-gated channels & Occur only in muscle cells and axons of neurons
Four main steps
Depolarization:
Na+channels open
Repolarization:
Na+ channels are inactivating, and K+ channels open
Resting state:
All gated Na+ and K+ channels are closed
Hyperpolarization:
Some K+ channels remain open, and Na+ channels reset
Major divisions and subdivisions of the nervous system
Divisions
ANS:
Contains motor neurons that innervates smooth & cardiac muscles as well as glands.
SNS:
Extends in spinal or cranial nerves directly to skeletal muscles
Subdivisions
PNS:
: Provides links from and to world outside body
CNS:
ONLY consists of the brain & spinal cord
Major parts and functions of the spinal cord
Functions
Major reflex center: reflexes are initiated and completed at spinal cord
Provides two-way communication to and from brain and body
Major Parts
Thoracic (chest)
Lumbar (lower back)
Cervical (neck)
Neurotransmitters
Major neurotransmitters of ANS are acetylcholine (ACh) and
norepinephrine (NE)
Ach (same as ACh used by somatic motor neuron) is released by cholinergic fibers
NE is released by adrenergic fibers
Effects of neurotransmitter depends on whether it binds to cholinergic receptor or adrenergic receptor
Compare & contrast the autonomic nervous system
Sympathetic
Fight or Flight response:
Mobilizes body during activity, exercise, excite, dry mouth, sweaty & heart rate
Parasympathetic
Rest & Digest Relaxed:
Maintenance functions, conveys energy, blood pressure, breathing rate & digestion
Reflex arc
Reflexes classified functionally
Somatic reflexes:
Activate skeletal muscle
Autonomic (visceral) reflexes:
Activate visceral effectors
Sensory neuron:
transmits afferent impulses to CNS
Integration center:
either monosynaptic or polysynaptic region within CNS
Motor neuron:
conducts efferent impulses from integration center to effector
organ
Effector:
muscle fiber or gland cell that responds to efferent impulses by
contracting or secreting
Receptor:
site of stimulus action
Disorders/Diseases
Disorders of ANS:
Hypertension(High BP), Raynaud's Disease & Autonomic Dysreflexia
Hypothalamic disturbances:
Severe body wasting, Obesity, Sleep disturbances, Dehydration & Emotional imbalances
Degenerative Brain Disorders :
Alzheimer’s disease (AD), Parkinson’s disease & Huntington’s disease
Drugs of abuse
Methamphetamine
: Responsible for rewarding pathway and highly addicting
Cocaine:
Responsible for rewarding pathway, voluntary movement, unable to stay still & abusive
Alcohol:
Responsible for memory, impulse control & decision making
LSD:
Responsible for locus coeruleus, wakefulness & hallucinogen
Heroin:
Responsible for the transmission of pain signals, stress response & emotional attachment
Ecstasy
: Responsible for sleep, mood, perception & appetite
Marijuna
: Responsible for slowing down movement making us feel calm