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Maria Palacios P2 Nervous System - Coggle Diagram
Maria Palacios P2 Nervous System
Major Functions
Sensory input
Integration & processing
Motor output
Controls muscles & glands
Thinking
Movement
Internal processes of physiology
Decision- making
Sensory Function
detect internal & external changes
sends info. to CNS
Integrative Function
coordination of sensory info. in CNS
Motor Function
responds to decisions made in CNS
Divisions & Subdivisions
Central Nervous System
brain & spinal cord
responsible for integration of info. & decision-making
Peripheral Nervous System
cranial & spinal nerves that connect to CNS to the rest of the body
sensory (afferent) & motor (efferent) divisions
sensory fibers/ receptors to CNS
autonomic fibers connecting to viscera
Somatic N.S.
controls conscious/ voluntary
skeletal
muscles & skin (connects to CNS)
Autonomic N.S.
controls involuntary effectors (smooth/ cardiac muscles & glands)
Sympathetic
stress or emergency (fight/ flight)
lack of salivation
inhibits organs
short pregangolic fibers in grey matter
ganglia is closer to target organ
THORACOLUMBAR
Parasympathetic
normal, restful conditions
active digestion
constricts pupils
long pregangolic fibers from brainstem & sacrum of spinal cord
(CRANIOSACRAL)
Tissues
Neurons
cell body: contains nucleus
dendrites: impulses toward cell body; receive info. from neurons; communicates w/ neurons
axon: impulses away from cell body; arise from axon hillock; takes info. away from cell body
Neuroglia
supports neurons (nerve glue)
Microglia: small cells, produce scar tissues; against infection
Oligodendrocytes: form myelin sheath around axons in brain & spinal cord
Ependymal cells: produce cerebrospinal fluid in CNS
Astrocytes: between blood vessels & neurons; support, blood-brain barrier forms
Schwann cells: myelin-producing neuroglia
Satellite cells: provide protective covering around somas of neurons
Classification of Neurons
Multipolar: many dendrites & 1 axon (most in CNS)
Bipolar: 2 processes extending from soma - 1 dendrite 1 axon; found in nose, eyes, ears
Unipolar: 1 process from soma - splits into 2 parts that function 1 axon; sensory neurons
Sensory (afferent): impulses from peripheral receptors to CNS; unipolar or bipolar; sends sensory info. to CNS; from tissues & organs to brain & spinal cord
Interneuron: multipolar; sends info. between sensory & motor neurons
Motor: multipolar; from CNS to effectors (muscles/ glands)
Connective Tissue Coverings
3 membranes between skull bones, vertebrae, & soft CNS tissue
Dura Mater
outermost layer
tough, thick, dense connective tissue
sheath around spinal cord is separated from vertebrae by epidural space
Arachnoid Mater
middle layer
between arachnoid & pia mater is subarachnoid spaace - cerebrospinal fluid & blood vessels
Pia Mater
innermost layer
Parts/ Functions of Brain
Cerebrum
largest portion; higher mental functions; sensory & motor functions
Diencephalon (Thalamus/ Hypothalamus)
processes sensory input & controls homeostatic processes
-between hemispheres & above midbrain
Cerebellum
coordinates muscular activities (coordination & balance)
Brainstem
coordinates & regulates visceral activities (heartbeat, breathing, internal organs)
connects diff. parts of N.S.
Parts/ Functions of Spinal Cord
begins @ base of the brain
Cervical Enlargement
thickened area near top of spinal cord
provides nerves to upper limbs
Lumbar Enlargement
thickened region near bottom of spinal cord
rise to nerves that serve to lower limbs
Cauda Equim (horse's tail)
formed where spinal cord tapers to a point inferiorly
consists of spinal nerves in lumbar & sacral areas
31 segments connect to spinal nerves
.
butterfly shape w/ white matter core & grey matter
white matter: myelinated fibers - nerve tracts
grey matter: unmyelinated fibers - houses interneurons & neuron cell bodies
dorsal root gangolia outside spinal cord
grey matter makes posterior & anterior horns - between is lateral horn
central canal in middle of grey matter (CSF)
transmits impulses to & from the brain; houses spinal reflexes
Ascending tracts: carry sensory info. to the brain; descending tracts carry sensory info. from brain to muscles/ glands
Spinal reflexes: controlled by reflex arcs that pass through spinal cord
Cranial & Spinal Nerves
Cranial
I. Olfactory
II. Optic
III. Oculomotor
IV. Trochlear
V. Trigeminal
VI. Abducens
VII. Facial
VIII. Vestibulocochlear
IX. Glossopharyngeal
X. Vagus
XI. Accessory
XII. Hypoglossal
Spinal
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal (coccyx/ tailbone)
Action Potential & Nerve Impulse
neuron cell membranes are polarized
Membrane potential: charge inside a cell
Resting membrane potential: charge inside cell at rest; -70 mV; negatively charged ions & protein found
Excitatory Stimulus: opens chemically - gated Na+ channels
Threshold stimulus: causes Na+ ions to enter neuron
Depolarization: negative to positive charge inside neuron
Repolarization: action potential reached - cells return to resting potential (-70 mV)
Hyperpolarization: @ end of repol. - potential drops below -70mV
axon --> synapse --> dendrite --> cell body
Neurotransmitters
Acetylcholine
controls skeletal muscles & contractions
Norepinephrine
creates good feeling
released by all postgangolic neurons in sympathetic division
Dopamine
Histamine
released in hypothalamus - promotes alertness
Epinephrine
released w/ more. into bloodstream by adrenal glands when stimulated by sympathetic
Reflex Arc
Receptor --> sensory --> CNS --> motor --> effector
Reflexes: automatic responses to changes inside or outside of the body that maintain homeostasis
controls heart rate, blood pressure
Patellar (knee-jerk) reflex): extends knee
Withdrawal Reflex: response to touching something painful
Disorders
Cerebrovascular
confusion/ memory loss
Autism
erratic behavior
non-communicative
Alzheimer's disease
memory loss
Spinal Cord Injury
spinal cord damaged
Meningitis
damaged meninges
Multiple Sclerosis
T cells disfigured
Drugs of Abuse
Heroine
natural opiate - turns off dopamine
Ecstacy
seratonin - confuses transporters
Marijuana
acts as anandamine - inhibition gets turned off & releases dopamine
Methamphetamine
acts like dopamine
Alcohol
prevents glutamate exiting cells
Cocaine
blocks dopamine & receptors overstimulated
LSD
acts like serotonin; inhibits/ excites receptors