Nervous System,
Elena Trinh, Period 2
action potential
drugs that affect the brain
neuron
the nervous system
brain
layers of the meninges
neurotransmitters
functions
divisons
integration (interpreting the sensory input & what to do with it)
motor output (the response carried out)
sensory input (gathering info)
peripheral nervous system (PNS)
central nervous system (CNS)
brain & spinal cord
interprets sensory input & dictates motor output
spinal nerves carry impulses to & from the spinal cord
cranial nerves carry impulses to & from the brain
outside the CNS
subdivisions
sensory (afferent) division
motor (efferent division)
somatic sensory fibers convey impulse from the skin, skeletal muscles, & joints
nerve fibers convey impulses to the central nervous system from sensory receptors
visceral sensory fibers transmit impulses from visceral organs
transmits impulses from CNS to effector organs to activate muscles to contract & glands to secrete
subdivisions
somatic (voluntary) nervous system
autonomic (involuntary) nervous system
sympathetic division: fight or flight system
parasympathetic division: rest & digest system
regulates activity of smooth & cardiac muscles and glands
controls skeletal muscle
function
characteristics
classifications
structure
neurons vary, but all a cell body and at least one or more slender processes
conduct messages in the form of nerve impulses from one part of the body to another
amitotic (cannot be replaced if destroyed)
high metabolic rate (cannot function long without oxygen)
extreme longevity (can function optimally for a lifetime)
structural
functional
multipolar: 3+ processes
bipolar: 2 processes
according to the number of processes extending from the cell body
unipolar: 1 short process
sensory/afferent: from sensory receptors in the skin/internal organs toward the CNS
motor/efferent: away from the CNS to the muscles & glands
according to the direction nerve impulses travel relative to the CNS
association//interneuron: shuttle signals through CNS pathways
resting state: the default voltage level where all gates are closed
hyperpolarization: a small dip in voltage before returning back to resting state
depolarization: voltage levels approach its peak as sodium channels open
repolarization: voltage levels decline after peaking as sodium channels close & potassium channels open
how neurons communicate, integrate, and send messages to the rest of the body
classifications
by chemical structure
by function
amino acids
peptides
biogenic amines
purines
acetylcholine
gases & lipids
gasotransmitters
endocannabinoids
effects
actions
excitatory: cause depolarization
inhibitory: cause hyperpolarization
direct: bind to and open ion channels
indirect: act through intracellular second-messenger molecules
white matter: axons w fatty myelin sheath
ventricles: spaces in the brain where fluid resides
gray matter: short myelinated neurons
gyri: elevated ridges of tissue
cerebrum: the 2 cerebral hemispheres
sulci: shallow grooves between gyri
primary brain vesicles
midbrain: undivided
hindbrain: constricts & forms afterbrain & spinal brain
forebrain: divides into endbrain & interbrain
lobes
temporal: senses
parietal: processing sensory info, math, & language
frontal
occipital: visual recognition
lateral: above the fornix
third: below the fornix
fourth: below the cerebellum
left: mathematics, logicistics, forming sentences
right:creativity, arts (drawing, painting, music)
arachnoid mater: connects dura mater & pia mater
pia mater: provides nutrients to the brain by blood vessel
dura mater: supports & covers the brain
brain diseases
Parkinson's disease: degeneration of dopamine leads to persistent tremor, stiff facial movement, bent posture
Huntington's disease: massive degeneration of basal nuclei & causes wild, jerky body movements
Alzheimer's disease: deterioration of the brain & leads to dementia
compare:
contrast:
both have motor fibers
different efferent pathways & ganglia
different target organ responses
different effectors
click to edit
SNS: innervated skeletal muscle
ANS: innervated cardiac & smooth muscle and glands
ANS: uses 2-neuron chain
SNS: cell body & single thick myelinated axon
ANS: release fibers
SNS: release ACh
keeps body energy as low as possible (relaxing & reading after a meal)
mobilizes body during activity (excitement, exercise, emergency, embarrassment)
methamphetamine
alcohol
marijuana
cocaine
ecstasy
LSD
heroin
inhibitory transmitters are shut down & dopamine is released
produces feelings of sedation & well-being
ecstasy is taken in & serotonin is released
addictive; affects mood, sleep, perception, & appetite
turn off inhibitory transmitters so that dopamine is released
removes unnecessary short-term memories & slows down movement, causing relaxation
mimics dopamine so that dopamine is released instead of taken in
highly addictive; feelings of intense pleasure & exhilaration
binds to glutamate receptors, preventing cell excitement
affects memory formation, decision making, & impulse control
blocks dopamine transmitters & overstimulates the cell
often fidgeting & not still
inhibits serotonin receptors & excites them
feelings of wonderfulness & evoking a startled response to unexpected stimulus