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Nervous Jazlynn Banuelos p.3 - Coggle Diagram
Nervous Jazlynn Banuelos p.3
Nerves
Cranial
Location
Twelve pairs arise from the underside of the brain.
Type
sensory & motor nerve fibers
Function
send electrical signals, help you taste, smell, hear and feel sensations.
Designation
designated by number and name; the numbers
are in order, from superior to inferior.
Spinal
Location
spinal nerves arise from spinal cord,
Function
send electrical signals between the brain, spinal cord & body, help feel sensations (sensory nerve) & move your body (motor nerves
Type
all except the first pair are mixed nerves.
Designation
Numbered in sequence: 8 pairs of cervical nerves, 12 pairs of thoracic nerves, 5 pairs of lumbar nerves, 5 pairs of sacral nerves and 1 pair of coccygeal nerves.
Action Potential & Nerve Impulse
Upon reaching threshold potential, voltage-gated Na+ channels open, charging to about +30 mV
Caused when different ions cross the neuron membrane
Stages
Depolarization,
Positive change from resting potential
Hyperpolarization
Negative change in membrane potential
Repolarization
When action potential is reached, cells return to resting potential
Occurs when charge reaches -55mV
Brain
Parts & Functions
Cerebrum
largest portion; associated with high mental functions & sensory & motor neurons
Structure
Corpus callosum
flat bundle of nerve fibers that connects the
hemispheres.
Gyri
ridges
Sulci
grooves
Fissures
deep grooves
Lobes
frontal, parietal, occipital, temporal
Diencephalon
processes sensory input & controls many homeostatic processes
Structure
thalamus
sort and directs sensory info from parts of the nervous system to cerebral cortex
hypothalamus
maintains homeostatis by regulating variety of visceral activities & linking endocrine system to nervous system
Cerebellum
coordinates muscular activity
Structure
Made up of 2 hemispheres,gray matter lies outside a core of white matter called the arbor vitae.
Brainstem
coordinates & regulates visceral activities & connects different parts of the nervous system
Structure
Midbrain
between diencephalon & pons,main motor pathways between cerebrum and lower portions of the nervous system.
Pons
between midbrain & medulla oblongata.Contains centers that help regulate the rate and depth of breathing.
Medulla Oblongata
transmits all ascending and descending impulses
between the brain and spinal cord.
Spinal Cord
Parts
White matter
bundles of myelinated nerve fibers surrounding gray matter
Gray matter
Houses interneurons and neuron cell bodies
Dorsal Root Ganglia
convey information
Central Canal
middle of gray matter containing cerebrospinal fluid
Lateral horns
upper and lower wings of gray matter form the posterior and anterior horns; between them is the lateral horn.
Functions
Transmits impulses to and from the brain, and to house spinal reflexes
Ascending tracts
carry sensory information to the brain
Descending tracts
carry
motor information from brain to muscles or glands.
Spinal reflexes
controlled by reflex arcs that pass through the spinal cord.
Major divisions & Subdivisions
Peripheral Nervous System
Structure
cranial nerves, arising from the brain, and spinal nerves, arising from the spinal cord.
Somatic nervous system
connects the CNS to skeletal muscles & the skin, & oversees conscious activities.
Autonomic nervous system
connects the CNS to viscera, & controls subconscious activities.
Sympathetic division
active in conditions of stress or
emergency (fight or flight).
Parasympathetic division
active under normal, restful
conditions (rest and digest).
Central Nervous System
Structure
Brain & Spinal Cord
Function
Responsible for integration of information and decision-making.
Neurotransmitters
Function
chemical messengers in a synapse, that convey an electrical impulse from a neuron to another cell.
Types
Acetycholine
Control skeletal muscle action, stimulate skeletal muscle contraction and ,ay excite nervous system actions
Norepinephrine
Creates sense of feeling good and may excite autonomic nervous system actions
Dopamine
Creates sense of feeling good and limit actions in autonomic nervous system; may excite
Serotonin
Primarily inhibitory; leads to sleepiness
Hystemine
Release in hypothalamus promotes alertness
Major Functions
Sensory
Detects internal or external changes and carries information from receptors to sensory neurons
Integrative
Coordinates sensory information to the CNS, basis for decision making
Motor
Effectors respond to decisions made in the CNS
Compare & Contrast
Contrast
Consists of nerves that connect to CNS to visceral organs
Comparison
Made up of brain and spinal cord and nerves that branch off spinal cord
Classification of Neurons
Structural
Multipolar
Many dendrites and one axon
Bipolar
have 2 processes extending from cell body, a dendrite and an axon
Unipolar
1 process extending from cell body
Functional
Sensory (afferent)
Conduct impulses from peripheral receptors to CNS, some unipolar, some bipolar
Interneurons (interneural)
Multipolar neurons within the CNS forming links between other neurons
Motor (efferent)
Multipolar that conduct impulses from CNS to peripheral receptors
Reflex Arc
Function
Provide a basis for involuntary actions called reflexes
Components
Sensory neuron,sensory receptors, Interneuron, motor neuron, effectors
Process
Receptor
-> sensory neuron ->
Central Nervous System
-> Motor neuron ->
Effector
Disorders/Diseases
Cerebrovascular Accident (Stroke)
Risk Factors
diabetes, high cholesterol, increasing age
Symptoms
Severe headache, loss of coordination & balance, confusion or memory loss
Description
Occurs when blood flow to a portion of the brain is halted
Autism
Description
A brain disorder that makes it difficult to communicate
Risk Factors
Family history, hereditary, environmental
Symptoms
Anxiety, depression, repeated behaviors
Alzheimer's Disease
Description
A form of dementia associated with age
Risk Factors
memory loss, confusion & disorientation, unfounded suspicions
Symptoms
Memory loss, confusion & disorientation, unfounded suspicions
Spinal Cord Injury
Description
Damage to the spinal cord
Risk Factors
direct injury or disease, assault, fall, accident, weakened vertebral column
Symptoms
weakness, spastic muscles, paralysis
Meningitis
Description
Infection in the meninges surrounding the brain
Risk Factors
Bacteria or viral infection, drug allergies, fungi or parasites
Symptoms
Nausea & vomiting, fever & chills, stiff neck
Multiple Sclerosis
Description
Autoimmune disease that damages the myelin sheath
Risk Factors
Hereditary, family history, possible viral infection
Symptoms
Muscle weakness spasms, tremors & numbness, vision & hearing loss
Connective Tissue Coverings
Epineurium
Outer covering of a nerve
Perineurium
Covering around fascicles (bundle) of nerve fibers
Endoneurium
Covering around individual nerve fibers (axons)
Drugs of Abuse
Heroin
Interference
Inhibitory & Dopamine neurotransmitters
Affect on Brain
Mimics opiates & binds to opiate receptors causing dopamine to flood & produce feeling of sedation
Person
Use as a painkiller
Marijuana
Interference
Inhibitory and dopamine neurotransmitters
Affect on Brain
Mimics anandamide & binds to cannabinoid receptors cusing dopamine to squirt into synapse
Person
Affects memory and speed of movements
Alcohol
Interference
GABA inhibitory neurotransmitters & Glutamate neurotransmitters
Affect on Brain
Delivers double sedative punch, 1st making GABA receptors more inhibitory & binding, preventing glutamate from exciting cell
Person
Affects memory formation, decision making and impulse control
LSD
Interference
Serotonin neurotransmitters
Affect on brain
interacts with particular receptors which they may exhibit and excite
Person
Affects feeling of wakefulness and response to unexpected stimulus
Cocaine
Interference
Dopamine neurotransmitters
Affect on Brain
Blocks transporters leaving dopamine trapped in synaptic cleft causing overstimulation
Person
Affects voluntary movements causing fidgeting and unable to sit still
Methamphetamine
Interference
Dopamine neurotransmitters
Affect on brain
Dopamine in the cell works in reverse. Dopamine become trapped in synapse, overstimulating the cell
Person
Makes the used feel intense pleasure and exhilaration
Ecstasy
Interference
Serotonin neurotransmitters
Affect on Brain
Alters transporter making it confused & starts to work in reverse. Serotonin becomes trapped in synaptic cleft causing cells to overstimulate
Person
Affects sleep, perception, appetite, reward pathway causing addictive properties
Tissues
Neurons
Function
cells that communicate, via electrical impulses, with other neurons or other tissues.
Structure
a cell body, tubular cytoplasm-filled dendrites, and a tubular, cytoplasm-filled axon.
Neuroglia
Function
cells that support, nourish, protect, and insulate neurons.
Structure
Central
Microglia
small cells that function as phagocytes for bacterial cells and cellular debris, and produce scar tissue in sites of injury.
Ependymal cells
produce cerebrospinal fluid in CNS.
Oligodendrocytes
form the myelin sheath around axons in the brain and spinal cord.
Peripheral
Schwann cells
he myelin-producing neuroglia of the PNS.
Satellite cells:
provide protective coating around cell bodies of neurons in the PNS.