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Jenavieve Sagasta, The Nervous System - Coggle Diagram
Jenavieve Sagasta, The Nervous System
Drugs of Abuse
Heroine
Interferes with- Neurotransmitter, Dopamine Neurotransmitter, Opiate Neurotransmitter, and Dopamine Receptor
Binds to opiate receptors and turns off dopamine innibition, dopamine floods synapse which produces feeling of sedation and well being.
pain becomes numb, less stress and have positive emotions
Ecstasy
Interferes with seratonin neurotransmitters, seratonin receptors and seratonin transporters
taken by seratonin transporters, the transporter becomes confused and starts pushing seratonin out, seratonin over stimulates cell.
Person experiences changes in moos, lacks sleep and appetite. Since seratonin is being affected it either hightens or decreases
Marijuana
interferes with inhibitory neurotransmitters, dopamine neurotransmitter, cannbinoid receptor and dopamin receptor
THC binds to cannabinoid receptors and innibition is turned off and dopamine is put into synapse
usually have short memory spans, slows down movement, and makes a person feel relaxed
Methamphetamine
interferes with dopamine neurotransitter, dopamine transporters and dopamine receptor
enters dopamine and forces dopamine molecules out , transporter force dopamine into synapse its trapped and overstimulates the cell
feeling of intense pleasure and exhiliaration, usually paranoid
Alcohol
Interfere with GABA inhibitory neurotransmitter and GABA receptors , in another part of brain it affects the glutamate receptors and glutamate neurotransmitter
Double punch,first interacts with GABA receptors then inhibitory, it binds to glutamate receptors, prevents it from exciting the cell.
affects areas of brain thats responsible for memory, decision making,and impulse control.Person is more drousy and has numbing sensation
Cocaine
interferes with dopamine neurotransmitter, dopamine transporters, and dopamine receptors
blocks transports leaving dopamine trapped in synaptic cleft, dopamine binds again and again overstimulating the cell
people are fidgety and unable to keep still and is paranoid
LSD
interferes mainly with seratonin neurons, seratonin receptors and seratonin neurotransmitters
interacts with seratonin type 1 and 2 . Sometimes it inhibits them, it can excite them
changes perception of reality , making them more awake and branch to many sensory areas.
Classification of Neurons
are structural units of nervous system,Large, highly specialized cells that conduct impulses,All have cell body and one or more processes,
Neuron Cell Body
Synthesizes proteins, membranes, chemicals,contains nucleus with nucleolus; Some contain pigments,plasma membrane is part of receptive region that receives input info from other
neurons,
Nuclei: clusters of neuron cell bodies in CNS
Ganglia: clusters of neuron cell bodies in PNS
Multipolar: three or more processes (1 axon, others dendrites),Most common and major neuron type in CNS
Bipolar: two processes (one axon, 1one dendrite),
Unipolar: one T-like process (two axons),pseudounipolar
Sensory
ransmit impulses from sensory receptors toward CNS,almost all are unipolar, ganglia in PNS
Motor
Carry impulses from CNS to effectors,Multipolar, Most cell bodies are located in CNS
Interneurons
Lie between motor and sensory neurons,Most are entirely within CNS,99% of body’s neurons are interneurons
Cranial Nerves
I: Olfactory nerves
Sensory nerves of smell,Fibers synapse in olfactory bulbs,Pathway terminates in primary olfactory cortex,
II: Optic nerves
Arise from retinas; really a brain tract,ass through optic canals, converge, and partially cross over at optic chiasma,optic tracts continue to thalamus, where they synapse,Optic radiation fibers run to occipital (visual) cortex, purely sensory
III: Oculomotor nerves
Fibers extend from ventral midbrain through superior orbital fissures to four of six extrinsic eye muscles,function in raising eyelid, directing eyeball, constricting iris (parasympathetic), and
controlling lens shape
IV: Trochlear nerves
Fibers from dorsal midbrain enter orbits via superior orbital fissures to innervate superior oblique muscle,primarily motor nerve that directs eyeball
V: Trigeminal nerves
Largest cranial nerves
Ophthalmic (V1) passes through superior orbital fissure
Maxillary (V2) passes through foramen rotundum
Mandibular (V3) passes through the foramen ovale
VI: Abducens nerves
Primarily a motor, fibers from inferior pons enter orbits via superior orbital fissures
VII: Facial nerves
Motor functions include facial expression, parasympathetic impulses to lacrimal and salivary glands
VIII: Vestibulocochlear nerves
Mostly sensory function; small motor component for adjustment of sensitivity of receptors
IX: Glossopharyngeal nerves
Motor functions: innervate part of tongue and pharynx for swallowing and provide parasympathetic fibers to parotid salivary glands
Sensory functions: fibers conduct taste and general sensory impulses from ,harynx and posterior tongue, and impulses from carotid chemoreceptors and baroreceptors
X: Vagus nerves
Only cranial nerves
Most motor fibers are parasympathetic fibers that help regulate activities of heart, lungs, and abdominal viscera
Sensory fibers carry impulses from thoracic and abdominal viscera, baroreceptors, chemoreceptors, and taste buds of posterior tongue and pharynx
XI: Accessory nerves
ormed from ventral rootlets from C1 to C5 region of spinal cord (not brain)
Accessory nerves exit skull via jugular foramina to innervate trapezius and sternocleidomastoid muscles
XII: Hypoglossal nerves
Innervate extrinsic and intrinsic muscles of tongue that contribute to swallowing and speech
Neurotransmitters
Language of nervous system,Most neurons make two or more neurotransmitters,
Chemical structure
Acetylcholine (ACh)
– First identified and best understood,Synthesized from acetic acid and choline by enzyme choline acetyltransferase
Catecholamines
Dopamine, norepinephrine (NE), and epinephrine: made from the amino acid
tyrosine
Indolamines
Serotonin: made from the amino acid tryptophan
Histamine: made from the amino acid histidine
Amino acids
Amino acids make up all proteins: therefore, it is difficult to prove which are
neurotransmitters
Function
Effects: excitatory versus inhibitory
Neurotransmitter effects can be excitatory (depolarizing) and/or inhibitory hyperpolarizing)
Actions: direct versus indirect
Direct action: neurotransmitter binds directly to and opens ion channels
Indirect action: neurotransmitter acts through intracellular second messengers
Compare & Contrast the Autonomic Nervous System
consists of motor neurons that intervate smooth muscles, cardiac muscle, and glands and make adjustments to ensure optimal support for body activities
Parasympathetic division: promotes maintenance functions,
conserves energy
Sympathetic division: mobilizes body during activity
Dual innervation: all visceral organs are served by both divisions, but these divisions cause opposite effects
Connective Tissue Coverings
Gyri: ridges
Sulci: shallow grooves
Fissures: deep grooves
Longitudinal fissure: Separates two hemispheres
Transverse cerebral fissure:Separates cerebrum and cerebellum
sulci divide
Frontal, Parietal,Temporal,Occipital, Insula
Spinal Nerves
Part of PNS
Attach to spinal cord by 31 paired roots
Each spinal cord segment is designated by paired spinal nerves that arise from it
Gray matter is located in core, white matter outside
formed by fusion of dorsal and ventral roots
Ventral Roots
Contain motor (efferent) fibers from ventral horn motor neurons that innervate
skeletal muscles
Dorsal Roots
Contain sensory (afferent) fibers from sensory neurons in dorsal root ganglia
that conduct impulses from peripheral receptors
Disorders/Diseases
Alzheimer's Disease
results in dementia
Neurofibrillary tangles inside neurons interfere with transport mechanisms eventually killing the neuron
Parkinson's Disease
degeneration of dopamine-releasing neurons of substantia nigra
Basal nuclei deprived of dopamine become overactive, resulting in tremors at rest
Huntington's Disease
fatal hereditary disorder caused by accumulation of protein huntingtin in brain
cells
initial symptoms include wild, jerky “flapping” movements
Cerebrovascular Accident
occurs when blood flow to a portion of the brain is halted, certain types are hereditary, some causes are blood vessels being clogged and high cholesterol.
Symptoms: Severe headache , change in hearing,taste, touch or vision and alertness
Treatment: hospitalization, blood thinners, surgery
Autism
brain disorder that makes it difficult to communicate. Cause it not well understood, it can be hereditary,environmental and occurs in mostly males
Symptoms: decay in learning,repeated behaviors,anxiety and depression
Treatment: medications, coping skills,specialized behaviors, behavioral management
Alzheimer´s disease
a form of dementia associated with age, its hereditary , some risk factors are high insulin, and occurs in people over 60
Symptoms: memory loss, confusion and disorientation, and mood and behavior changes
Treatment: uncurable, can be helped with medication,removing behavior triggers, and stem cells
Spinal Cord injury
damage to the spinal cord, some causes are direct injury or disease, assult, fall,accident,weakened vertebral column and occurs in men ages 15-35
Symtoms: weakness, loss of feeling, spastic muscles, and loss of bladder and bowl control
Treatment: Medication, surgery and bed rest
Meningitis
infection in the meninges, causes are bacteria or viral infection , drug allergies and fungi or parasites
Symptoms: Neusea and vomitting, sensitive to light, and fever and chills.
Treatment: hospitalization, antibiotics,and medication
Multiple Sclerosis
Autoimmune disease that damages the myelin sheath, its not understood, its hereditary, its caused by nerve damage and inflammation, usually diagnosed between ages 20-40
Symptoms: muscle weakness,spasms, tremors,and numbness, constipation,vision and hearing loss
Tremors: medication slow disease progress, steroid treatments, and physical therapy
Tissues
Neuroglia (glial cells): small cells that surround and wrap delicate neurons
Neurons (nerve cells): excitable cells that transmit electrical signals
Major Parts and Functions of the Spinal Cord
Ventral (anterior) median fissure
Dorsal (posterior) median sulcus
Dorsal Horns
interneurons that receive somatic and visceral sensory input
Ventral horns
some interneurons; somatic motor neurons
Lateral horns
Sympathetic
neurons
Gray commissure
bridge of gray matter that connects masses of gray matter on
either side
Ventral roots
bundle of motor neuron axons that exit the spinal cord
Dorsal roots
sensory input to cord
Dorsal root (spinal) ganglia
cell bodies of sensory neurons
Reflex Arc
Receptor
site of stimulus action
Sensory neuron
transmits afferent impulses to CNS
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
Somatic reflexes
Activate skeletal muscle
Autonomic (visceral) reflexes
Activate visceral effectors (smooth or cardiac muscle or glands)
Major Functions and Subdivisions of the Nervous System
Sensory input
Information gathered by sensory receptors about internal and external changes
Integration
Processing and interpretation of sensory input
Motor output
Activation of effector organs (muscles and glands) produces a response
Central nervous system (CNS)
Brain and spinal cord of dorsal body cavity
Integration and control center: Interprets sensory input and dictates motor output
Peripheral nervous system (PNS)
outside CNS
Spinal nerves to and from spinal cord
Cranial nerves to and from brain
Sensory (afferent) division
Somatic sensory fibers: convey impulses from skin, skeletal muscles, and joints to CNS
Visceral sensory fibers: convey impulses from visceral organs to CNS
Motor (efferent) division
Transmits impulses from CNS to effector organs
Somatic nervous system (voluntary)
Somatic motor nerve fibers conduct impulses from CNS to skeletal muscle
Autonomic nervous system (involuntary)
Regulates smooth muscle, cardiac muscle, and glands
Sympathetic
Parasympathetic
Major Parts and Functions of the Brain
Cerebral hemispheres
Diencephalon
Brain stem
Mid brain, Pons, Medulla
Cerebellum
Gray Matter
short, nonmyelinated neurons and cell bodies
White Matter
myelinated and nonmyelinated axons
Ventricles
filled with cerebrospinal fluid
lateral ventricles- large, c-shaped, deep in chambers
third ventrcles- connected to lateral ventricles, in diencephalon,
fourth ventricle- connected to third ventricle via cerebral aquaduct, in hindbrain,
Action Potential & the Nerve Impulse
Action potentials: Long-distance signals of axons, main way to send signals,only in muscle cells and axons of neurons,in neurons, aka nerve impulse
Resting state: All gated Na+ and K+ channels are closed
Only leakage channels for Na+and K+are open
Depolarization: Na+channels open
Na+rushes into cell
Repolarization: Na+ channels are inactivating, and K+ channels open
Hyperpolarization: Some K+ channels remain open, and Na+ channels reset
nside of membrane becomes more negative than in resting state
