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Nervous System Nadya Hernandez 4 (drugs + how brain is affected by them…
Nervous System Nadya Hernandez 4
major functions
collecting sensory input, processing sensory input, and responding to sensory input accordingly
divisions of nervous system AND PNS
Central Nervous System - brain + spinal cord. integrative control centers
Peripheral Nervous System - cranial + spinal nerves. connects cns to body
motor (efferent; away from pns)
autonomic - involuntary and goes from cns to cardiac + smooth muscle
sympathetic - mobilizes body
parasympathetic - conserves energy and digests
somatic - voluntary and goes from cns to skeletal muscles
sensory (afferent; to pns)
Layers of Meninges / coverings
dura mater - has 2 layers - thick dense irregular connective tissue right under bone + periosteum
arachnoid mater - under dura mater - has arachnoid granulations which allows absorption of CSF fluid
pia mater - under arachnoid mater - plastic wrap 4 brain - tender...
Neuron Classification
Structurally: -unipolar -bipolar -multipolar (sensory neurons can be any, but motor are only multipolar)
Functionally: -sensory -motor -interneuron
brain lobes
frontal - primary motor area and is associated w personality
temporal - auditory processing and sensory speech
occipital - primary visual area + visual association area
parietal lobe - primary somatosensory area + somatosensory association area + primary taste area
autonomic system (part of PNS)
sympathetic: -excitement+ emergecny + embarrassment + exercise -preganglion are in spinal cord T1-L2 -inhibits digestion + increases heart rate -longer effects bc of norepinephrine
parasympathetic -shorter effects bc ACh wears off quickly -preganglionic fibers extend from CNS almsot to organs -allows digestion + decreases heart rate . just wants to vibe
drugs + how brain is affected by them
alcohol - depressant that inhibits glutamate which is a neurotransmitter responsible for anxiety (and other things but alcohol's inhibition of it causes less anxiety)
meth - acts as a decoy for dopamine so it takes its place in the vesicle, kicking dopamine out and forcing it to overstimulate the brain and the reward pathway
marijuana - THC mimics anandamide so it takes its place in the receptor so the dopamine inhibitory walls are taken down, so dopamine can "squirt" into the system
cocaine - blocks dopamine transporters so the dopamine is forced to overstimulate the cell
MDMA - confuses serotonin transporters, so the serotonin is taken out of its home and is left to bind + overstimulate the cell over and over
LSD - binds to serotonin receptors, but may inhibit some and excite some, giving complex effects
heroin - mimics natural opiates which take down dopamine walls, so dopamine Floods synapse
action potential
resting state: all voltage gated Na and K channels are closed
depolarization: voltage gated Na channels open. it is urged on when levels of voltage reach threshold
repolarization: Na channels are inactivating and K channels open so the K can restore neuron's internal negativity
hyperpolarization: some K channels stay open and Na channels reset. looks like slight dip in rollercoaster
neurotransmitters
catecholamines: dopamine, norepinephrine, epinephrine / indolamines: serotonin, histamines
amino acids: glutamate, aspartate, glycine,gamma-aminobutyric acid
gastroransmitters: NO, CO, H2S
function: excitatory vs inhibitory, direct vs indirect
endocannabinoids: involved in learning + memory
peptides: substance P (mediator of pain signals), endorphins (natural opiates)
tissues
structure
cell body: nucleus is enclosed by perikaryon. contains melanin + lipofuscin. has microtubules + neurofibrils
rough er surrounds nucleus
axons: carry signals away from cell. dendrites: carry signals to cell
PNS: has schwann and satellite neuroglia
CNS: has oligodendrocytes, microglia, astrocytes, and ependymal neuroglia
function of neuron
chemical synapse: inhibition and excitement of neurotransmitters + an action potential
electrical synapse: these can only excite the cell
transferring info through axons, dendrites, and synapses
cranial nerves / major body nerves
olfactory nerve: guess!!! take a guess what its for.
oculomotor: raising eyelids,directing eyeball, and controlling shape of lens
optic: arise from retinas, synapse @ thalamus
trochlear: primarily motor nerve directing eyeball
trigeminal: largest cranial nerves. (epithalamic, maxillary, mandibular). senses facial stuff
abducens: innervates lateral rectus muscle. primarily motor nerve
facial: taste, spit glands, facial Expression
vestibulocochlear: afferent from hearing receptors. auditory.
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diseases + injuries
alzheimers: results in dementia caused by senile placques and neuron tangles
parkinson's: degeneration of dopamine-releasing neurons in the substantia nigra (parkinson's not dope) (haha pun)
huntington's: huntingtin (mutant) protein accumulates and kills off brain tissue
cardiovascular accident: stroke . just say stroke for the love of christ
concussion: ahh i got a caucasian !!!!!! meaning i got a mild bonk on my head... mild traumatic injury
contusion: HARD bonk on the head :(
anatomy + major parts + functions of spinal cord
protection: cerebrospinal fluid, bone, meninges
dorsal + ventral roots: projections of gray matter
provides 2 way conduction pathway (ascending and descending)
white matter is divided into 3 white columns called funiculi
spinal dura mater: single layer unattached from walls
epidural space: space btwn vertebrae + dura mater filled w fat and veins !
central / ependymal canal: CSF filled tube running along spinal cord
spinal nerves / dermatomes / major body nerves
31 pairs
all are mixed nerves named for point of issue from spinal cord
supply all body except for brain + neck (cranial nerve job)
C1-C8, T1-T12, L1-L5-S1-S5, C0
ventral roots: contain ventral neuron motor fibers
dorsal roots: contain sensory fibers from dorsal root ganglia
reflex arc
receptor: responds to stimulus + initiates impulse by depolarization
sensory neuron: transmits afferent impulse
integration center: turns sensory to motor impulse. direct mono/polysynaptic region in CNS
motor neuron: gets the now efferent impulse and takes it to effector
effector: muscles and glands
spaces and ventricles (spaces of brain filled w CSF)
ventricle 1 & 2: called the "lateral ventricles". they mirror each other from each hemisphere.
ventricle 3: in between the hemispheres. sends and receives messages from the lateral ventricles. kinda like an involuntary UPS man
ventricle 4: spans from obex @ medulla oblangata to the cerebral aqueduct. protects brain from trauma and helps form central canal. big when found under the arbor vitae
parts of brain and function:
brain stem: midbrain: auditory and visual reflex, pons: relays convos btwn motor cortex and cerebellum, medulla: necessary rhythmic movement
epithalamus: pineal gland that secretes melatonin
hypothalamus: physical responses to emotions, regulates body temp + food intake + sleep cycles. is connected to pituitary gland. controls autonomic system
thalamus: info is sorted and edited. organizer of the group !! mediates sensation + emotion .
cerebellum (hindbrain): precise timing & appropriate patterns of skeletal muscle contraction. calculates best way to coordinate force + direction . activity occurs subconsciously
pituitary gland: endocrine gland that controls function of other endocrine glands. hormones up the wazoo
optic chiasma: the optic nerves intersect here to be connected to the occipital lobe. located in forebrain
forebrain: cerebrum. go to "brain lobes" branch
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