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Nervous system - Coggle Diagram
Nervous system
Somatic motor system
supplementary motor area
receive info from the premotor cortex
programs the motor sequences
more of this area is required for more complex and repetitive actions
cannot orient body parts to perform action if part is damaged
premotor cortex
found in frontal lobe
develops the right strategy to perform the required movements
damage to this area prevents the selection of the appropriate strategy to perform an action
primary motor cortex area
activates the neurons that will activate the specific muscle to perform an action
found in the precentral gyrus in the frontal lobe
arranged as if the entire body was projected on it's surface
motor homunculus
specific area of the cortex activates specific muscle
fires ac when enough depolarization arrive at it's axon hillcock
midline to lateral (right side of map) on homunculus map
foot, ankle, knee, thigh, trunk, shoulder, elbow, wrist, hand, finger (big area), face, lips, jaw, tongue
basal ganglia
spinal pathways
corticospinal tract
main pathway from primary motor cortex to motor neurons that can stimulate muscle cells
composed of million of axons whose cell bodies are found in the primary motor cortex
tract
motor cortex
descends down to the brain stem
medulla
80% of nerve fibers cross to contralateral(opposite) side
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spinal cord
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motor nerves
muscle receptors
generate proprioception
muscle sense
receptors
muscle spindles
detects muscle stretch, length, and rate of change of muscle length
found inside the whole muscle, beside the real contractile muscle cells(extrafusal fibers)
made of
intrafusal muscle fibers
central sensory region
gamma motor neurons
activates intrafusal fibers
sensory neuron
comes from sensory region
stretches when spindles stretches (sensitive to shape change)
depolarizes
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alpha-gamma coactivation
makes sure muscle spindle continue to send info to the brain about proprioception during a muscle contraction
muscle contraction
only extrafusal fibers contract
intrafusal muscle fibers go slack
gamma motor neurons activate for proprioception
alpha motor neurons
activates extrafusal muscle fibers
gamma motor neurons
activates intrafusal muscle fibers
golgi tendon organs
detect muscle tension
prefrontal cortex
where the first thought to perform an action occurs
reflex arc
most basic type of integrated neural activity
requires
sensory/afferent neuron
one/more synapses
sensory receptor
one/more interneurons
motor/efferent neuron
effector organ
does not require brain output to cause muscle contraction
stretch reflex
tapping the tendon
small stretch in quadriceps muscle
muscle spindles stretch
ac triggered in afferent neurons
ac enters spinal cord
motor nerve of quadriceps activates while hamstring muscles are inhibited
quadriceps contracts, hamstring relaxes
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events
ANS
controls involuntary functions
HR
glands
pupils
smooth muscles in blood vessels
SYN
fight or flight situations
increase HR
dilate airways/vessels
adrenal organs only receive signals from here
nerves exit spinal cord in the thoracic and lumbar region
synapses to ganglia onto a postganglionic nerve
effector organ of interest
preganglionic neuron releases Ach
Ach stimulates postganglionic neuron
postganglionic neuron usually releases norepinephrine
target cell's receptor
sometimes releases Ach
PSYN
storage and conservation of energy (rest and digest)
slow HR
lower blood pressure
nerves exit brain stem and the very lower sacral region of spinal cord
preganglionic nerves synapse onto a postganglionic nerve close to an effector organ
effector organ of interest
preganglionic neuron releases Ach
longer than SYN axons
Ach stimulates postganglionic neuron
postganglionic cell ALWAYS releases Ach
target cell's receptor
one division of ANS would usually stimulate an organ while the other inhibits it
effect on some organs
Salivary glands
PSYN
water saliva
SYN
thick mucus produce dry mouth
pupils
PSYN
pupils constrict
SYN
pupils dilate, letting more light in
lungs
PSYN: bronchioles constrict
SYN: bronchioles dilate and lets more in
heart
PSYN
HR slows
SYN
HR, contraction force increases, ultimately increasing cardiac output (CO)
fat (adipose) tissues
PSYN: no effect
SYN: stimulates fat breakdown
kidney
SYN
more renin secretion, causing RAS to increase blood pressure
PSYN
no effect
adrenal glands
PSYN: no effect
SYN more epinephrine secretion
digestive system
PSYN
more digestive tract activity (motility and enzyme secretion
SYN
less digestive tract activity decreasing motility and digestive tract (motility and enzyme secretions)
blood diverted to working muscles
bladder
PSYN
releases urine
SYN
holds urine
Blood vessels, arterioles and veins
PSYN
no big changes
SYN
vasoconstriction of non-exercising organs
vasodilation in skeletal and cardiac muscle
increasing blood flow in these muscles
communication in the nervous system
information travels in action potentials
language of the nervous system
neural coding
detecting how much ac is required for an action (i.e. lifting heavy vs light object)
chemical synapse
how nerve cells communicate with one another
presynaptic nerve releases a neurotransmitter
neurotransmitter affects postsynaptic nerve
structure
axon terminal of the presynaptic cell
voltage gated Ca++ channels
synaptic vesicles with neurotransmitter
mitochondria
synaptic cleft
postsynaptic cell
chemical receptors (for neurotransmitters)
chemically gated ion channels (aka ligand-gated ion channels)
open when a chemical (i.e. neurotransmitter) attaches
sequence of events
presynaptic neuron make neurotransmitters stored in synaptic vesicles
ac in the presynaptic neuron depolarizes the membrane and open the Ca++ channels
Ca++ enter the axon terminal
Ca++ makes the synaptic vesicles fuse to the wall of synaptic terminal and cause exocytosis
neurotransmitter is released
neurotransmitters
chemicals released by neurons at the axon terminal
made in the neuron and stored in the synaptic vesicle
response in the postsynaptic neuron
excitatory
depolarization
easier to fire ac
inhibitory
hyperpolarization
harder to fire ac
groups of neurotransmitter
acetylcholine (Ach)
main neurotransmitters
biogenic amines
catecholamines
norepinephrine
epinephrine
dopamine
amino acids
inhibitory aa
GABA
glycine
excitatory aa
glutamate
aspartate
neuropeptides
endogenous opioids
vasoactive intestinal peptide
difference with NMJ
NMJ
1 ac potential in the motor neuron can produce 1 ac in the muscle cell causing contraction
chemical synapse
1 ac in the presynaptic neuron DOES NOT make an ac in the postsynaptic neuron
Ionic basis of postsynaptic potentials
excitatory postsynaptic potential (EPSP)
local depolarization of the membrane from Na+ entering the cell
local event diminishing with time and distant called a graded potential
no depolarization at the dendrite because no voltage gated channels present
to generate an ac, the EPSP MUST reach the axon hillcock
generating a strong enough EPSP to reach the axon hillcock
spatial summation of EPSP
additive effect of many ESP from many synapses arriving at the postsynaptic neuron at the same time
sufficient voltage-gated channels are activated
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temporal summation of EPSP
additive effect of many EPSP generated from 1 synapse firing at high frequency on the postsynaptic neuron
synaptic integration
the battle between number of EPSP and IPSP
the number of postsynaptic potentials that are more abundant will cause it's effect (i.e. depolarization or hyperpolarization)
inhibitory postsynaptic potentials (IPSP)
inhibitory neurotransmitters producing a local hyperpolarization
opens different chemically gated channels
open Cl- channels
lets Cl- in
open K+ channels
lets K+ out
makes it harder to fire an ac by producing stronger hyperpolarizations
both the EPSP and IPSP change the charge polarity of the post-synaptic membrane (i.e. the charge in the membrane can reverse)
structure of the brain
cells found in the brain
neurons
transmit and process info in the body
multipolar
many branching dendrites and one axon
standard neurons found in the CNS
unipolar
one process extending from the cell's body
found in the peripheral nerve outside the CNS
usually sensory neurons
transmit signal to and from the spinal cord
cell body is usually found leaning to one side of the axon
bipolar
two processes extending from cell body
found in the retina of the eye
glial cells
most abundant (90%)
outnumber neurons by 5x
regulate proper environment for neurons to function
support cells of the brain
regulation is done by regulating passage of substances between the blood and brain's interstitial space
performs a structural role
types
microglia
oligodendrocytes
produces myelin
astrocytes
anatomy
right/left hemisphere
signals in one hemisphere are sent to activate muscles in the other hemisphere
sensory signals from one side are sent to the opposite side of the brain (i.e. left side sensory signal to right hemisphere)
left hemisphere
language and mathematical area
helps understand visual and auditory info so then can formulate a spoken or written response
the brain stem
controls basic body functions (HR, respiration, etc.)
made up of
midbrain
connects the brainstem and diencephalon
controls auditory and visual motor reflexes
pons
relay station to pass info between cerebellum and cerebral cortex
coordinates and controls breathing
medulla oblongata
continuation of the spinal cord
control involuntary functions
breathing, blood pressure, etc
fibers from the corticospinal tract cross to the opposite side of the spinal cord here
innervates muscles on other side of the body
has 9 cranial nerves
cerebellum
found above the brain stem
controls coordinated movement
has the most neurons in the brain
has receptors
equilibrium
balance
somatic
motor neurons
to perform this function
receive same info from motor cortex traveling out to the muscles
compares info to ensure muscle is doing what it's supposed to do
if incorrect movement cerebellum modifies primary motor cortex signals
receive proprioception information
also corrects ongoing movements
also modifies strength of reflexes
Pavlovian conditioning
learning new muscle movements
vestibular ocular reflex(VOR)
limbic system
diencephalon
hypothalamus
controls endocrine functions
using hormones
important for homeostasis
acts with negative feedback systems
also important for body water regulation, food intake, temperature, circadian clock, emotions
thalamus
receives sensory info traveling to spinal cord
integrates info before it goes to the cortex
brain's emotional center
connects higher thought process with more primitive emotional responses
also important for feeding, drinking, pain, motivation and learning
amygdala
cingulate cortex
hippocampus
septum
surface of the brain
gyri
bumps in the brain
increases surface area of the brain
locations are consistent between individuals
sulci
dips in the brain
lobes
parietal lobe
primary somatosensory cortex
receives information from the major sensory organs (pain, temperature, touch, vibrations)
association areas
creates perceptions by incorporating sensory information with other association areas of the cortex
frontal lobe
motor association area (premotor cortex)
incorporates movement information from other sensory inputs to create perceptions of stimuli
prefrontal cortex
primary motor cortex
processes information received by skeletal muscles in the body
temporal lobe
primary auditory cortex
receives and processes information from auditory nerve and incorporates them with other sensory inputs
auditory association areas
other parts
short-term memory
olfaction (smell)
occipital lobe
primary visual cortex
receives info from the optic nerve
responsible for vision
visual association areas
processes visual information and incorporates them with other sensory information
corpus callosum
pathway to connect the two cerebral hemispheres
pituitary gland
regulates endocrine organs
anterior pituitary
derived from pharynx
releases hormones
LH
FSH
ACTH
TSH
GH
prolactin
posterior pituitary
derives from neural tissues of hypothalamus
releases hormones
oxytocin
vasopressin
regulated by hypothalamus (found below it)
optic chiasma
where optic nerves from each eye meet
optic nerves continues as optic tracts to the lateral geniculate bodies of the thalamus
axons extend to their own hemisphere on the primary visual area of the occipital lobe