nervous system Flashcards
what is the nervous system
system of cells that
- sense information in and around the body ,
- process or “make sense” of that information,
- respond to that information
main cell type of nervous system
neuron
nervous system box
STUDY IT IS ON THE TEST
the nervous system can broken down into what two arts
the central nervous system (CNS), Peripheral Nervous System (PNS)
CNS
brain, brain stem and spinal cord
PNS
nerves outside the CNS
how many neurons are inside brain
86 billion
the brain is like a what
processing center for information
what happens with signals in the brain
signals are sent here, compiled and then a response signal is sent away
the brain had many parts that what
reuglate different processes
what is the brain stem
a 3 inch region at base of the brain
what is regulated in the brain stem
involuntary activities
the three parts of the brain stem
the midbrain, the pons, the medulla Oblongata
what is midbrain
has oversight over vision hearing and alertness, most superior
what is pons
has oversight over breathing, connects brain to spinal cord
what is medulla oblongata
has oversight over heart rate, blood pressure, and vomiting , most inferior
where does the spinal cord run
through the spine
the spinal cord is like a what
“two way street” that carroes signals to and from the brain
what is coordinated at the spinal cord
reflexes are coordinated here, they do not go all the way up to brain because it is faster this way
what happens with spinal cord injury
loss of control over all nerves at and below injury
loss of functions at and below break of spine
paraplegia
what is the somatic nervous system apart of
PNS
what does the somatic nervous system do
controls voluntary actions like moving
what are the two parts of the somatic nervous system
sensory and motor
what does sensory part of somatic nervous do
receive signals like pain, heat, touch (afférent)
what does motor part of somatic nervous system do
move muscles (efferent)
what do the sensory and motor part of the somatic nervous system do
connect in the CNS
afferent neurons
run towards the CNS
efferent neurons
run away from the CNS
the autonomic nervous system is apart of what
PNS
what does the autonomic nervous system do
controls involuntary actions
two parts of the autonomic nervous system
the parasympathetic and sympathetic nervous systems
all sensory nerve
afferent
all motor nerves
efferent
the parasympathetic and sympathetic nervous systems
PSNS and SNS
what are reflexes
automatic and predictable responses to stimuli
reflexes can be what
somatic or autonomic
what muscle does somatic control
skeletal muscle
what muscle does autonomic
smooth or cardiac
how to tell if it’s somatic or autonomic
if you can do it right NOW
inside of a nerve usually has a charge more
negative than the outside
when certain events occur and stimulate the nerve, the nerves will
rapidly shift their internal charge from negative to positive
the shift of internal charge from negative to positive begins where
near the axon hillock and progresses down the axon (action potential)
when a nerve fires (depolarization and repolarization
action potential
neurons do not actually what
touch each other
what happens since neurons don’t actually touch
the electrical signal will end at the end of a nerve’s axon
synapse
a small space between neurons that is 25nm
signals are carried across a synapse by chemicals called a
neurotransmitters but, they are only released in response in response to an action potential
neurotransmitters can be what
excitatory or inhibitory
excitatory
invoke more action potentials in future neurons
inhibitory
prevent more action potentials in the future
after contact the postsynaptic neuron, the neurotransmitters can be
reputake, or broken down by enzymes
reuptake
absorbed by the presynaptic neuron for further use
some examples of neurotransmiters
GABA, glutamate, dopamine, epinephrine
resting potential
the slight negative charge of a neuron
typical resting potetial
-70mV
each neurotransmitter that bind to neuron leads to what
to the cell’s resting potential slightly
some excitatory NTs do what
open ion channels that let all ions in
what happens since the outside of the cell is more positive
mostly positively charged particles like K+,Na+, Ca+ trickle into the cell
some inhibitory NT’s do what
open other channels that only let negative ions like Cl-in, makes the neuron even ore negative
If a neuron’s resting potential exceeds a certain amount
the neuron will fire an action potential
an certain amount that the resting potential needs to exceed to to fire action potential
the threshold potential around -55mV
if neuron resting potential dosen’t exceed threshold potential
it won’t fire an action potential
the sharp increase in neuronal charge during action potential
depolarization
depolarization is due to what
influx of positive Na+ ions
GRAPH IS ON TEST
STUFY
Depolarization quickly reverses itself in
repolarization
repolarization requires
sodium/potassium pumps to pump
what happens in repolarization (potassium pump)
pump three sodium ions out of a cell while bringing two potassiums in for a net loss of positive charges inside the cell
repolarization works
against a concentration gradient
hyperpolarization
the cell goes further negative than normal -70 mV, then balances back out, this is called the refractory period
neurons cannot what
fire a new action potential until the refractory period ends
travels through bloodstream +
hormone
glands from the endocrine system secrete
hormones into bloodstream
hormones can
bind to neurons and cause excitatory or block inhibitory action potentials too
hormones are wht
much slower than neurotransmitters. last longer too
examples of hormones
testosterone, epinephrine
hormones are often
the same molecule or very similar to neurotransmitters
hormones fall into what three main classes
- steroids
- proteins
- amino acid derivatives
patellar reflex
when your doctor strikes your knee with a hammer and the result is a knee-jerk reaction
pupillary reflex
shining a light on one pupil, and both pupils contract when exposed to this light
ciliospinal reflex
pain to the neck, or upper trunk area will cause the pupils to dilate only on the ipsilateral side (side of the body that the pain is applied to)
diving reflex
slowing of heart rate in response to submersion in cold water
Westphal’s sign
absence of the knee jerk reaction when your knee is striked with a hammer
Adie Syndrome
Absence of both pupils contracting when light is shined on one pupil
patellar reflex is
somatic
pupillary reflex is
autonomic
ciliospinal reflex is
autonomic
diving reflex is
autonomic
babinski reflex
when the sole of the foot is stimulated with a blunt object ;;;somatic
Photic Sneeze Reflex
Sneezing in response to looking at the sun ; autonomic
Vagovagal Reflex
contracting GI in response to food ;autonomic
Cremasteric Reflex
contraction that draws testes up in response to stroking of inner thigh ; autonomic
Ankle Jerk Reflex
achilles tendon tapped foot jerks forward ; somatic
Blushing
reddening of face; autonomic
cough reflex
cough from sensitivity in airway linings; somatic
presynaptic neuron
neuron that delivers neurotransmitter
post synaptic neuron
receiver of neurotransmitter
paraplegia
loss of control over all nerves at and below spinal cord injury
nodes of ranvier
spaces between Schwann cells
Myelin Sheath
covers Schwann cells
Schwann cells
cells on the axon
axon terminal
releases neurotransmitters
axon hillock
soma connects to axon
soma
sums up received signals
dendrite
recieves signals (the branches off the soma)
part of neuron that sums up signals
soma
part of neuron that receives signals
dendrites
part of neuron that send signals
axon terminal
cerebrum
the main part of the brain
cerebellum
smaller, rounded structure at back of brain
brain stem ( for labelling )
connects brain the spinal cord
longitudinal fissure
divides the brain into 2 hemispheres, left and right
transverse fissure
divides the cerebrum from the cerebellum
sulcus
the groves between the gyri
gyrus
the pink part; ridge or fold between two clefts on the cerebral surface of the brain
frontal lobe
the the lobe at the front of the cerebrum
temporal lobe
lobes at the bottom of each side of cerebrum
occipital lobe
lobe in the back closest the cerebellum
pariental lobe
the biggest lobe at the top of the cerebrum
variety of what embedded in membrane of ells around the body
receptors
what are receptors looking for
specific signal or signals to cause them to do certain thing s
agonist
any chemical that binds to a receptor and activates it
antagonists
chemicals that bind to the receptor, but don’t turn them on, instead they sit on the receptor and block them fro being activated
agonist alone
full activation
agonist and antagonist
less activation
antagonist alone
no activation
what does the autonomic nervous system do
control body’s involuntary muscles
2 parts of autonomic nervous system
parasympathetic (PSNS) and sympathetic (SNS) systems
PSNS and SNS are in constant what
battle, trying to overtake or outweigh the other
sympathetic nervous system response
fight or flight
two hormones released in sympathetic nervous system
epinephrine (adrenaline) and norepinephrine
sympathetic NS is going to do what things to survive sabertooth tiger
- heart rate/volume up
- blood pressure up
- respiratory rate up
- airway dilates
- pupils dilate
- glycogenolysis in liver
- blood shunted away from GI
- blood shunted towards muscles
glycogenolysis
breaks glycogen into glucose
adrenergic receptors come in
variety of shapes and sizes and do different things, all part of sympathetic nervous system
adrenergic receptors
ay receptor where epinephrine or norepinephrine bind
subtypes of adrenergic receptors
alpha-1, alpha-2, beta-1, beta-2 , beta-3
parasympathetic nervous system
rest or digest (feed and breed)
main hormone involved in parasympathetic nervous system
acetylcholine (ACh)
parasympathetic nervous system will not help you
fight saber tooth tiger
what does parasympathetic nervous system do
SLUDGE-PM
what is SLUDGE-PN
Salivation (drooling) Lacrimation (tearing up) Urination (Peeing) Diaphoresis (sweating) GI upset (diarrhea) Emesis (vomiting) Priapism (erection) Miosis (pupils constrict)
speed of parasympathetic response
much slower than sympathetic
receptors that activate when acetylcholine binds to them
cholinergic receptors
two types of cholinergic receptors
muscarinic and nicotinic receptors
subtypes of muscarinic and nicotinic receptors
M1 through M5 muscarinic receptors and N1 and N2 nicotinic receptors
activation of cholinergic receptors causes
some of SLUDGE PM response to happen
what happens when acetylcholine binds to M2 receptors in heart
slow heart rate
what does atropine do
blocks M2 receptors, stopping ACh from binding there
what type of chemical is atropine
antagonist
who would you give atropine to
people whose hearts you want to go faster
beta-1 receptors?
located mostly on the heart, norepinephrine and epinephrine can bind to it
who do you give beta-blockers to
people whose hearts you don’t want to beat too fast, could stop heart attack
what happens when norepinephrine binds to beta-1 receptors
heart beats harder and faster
what is the suffix for beta-blockers
olol
what are beta blockers
drugs that block beta-1 receptors from binding to norepinephrine and epinephrine
epinephrine also binds to which important receptors located AROUND the body
beta-2 receptors
what happens when epinephrine binds to beta-2 receptors
the muscles in the bronchi in lungs relax, which allows the bronchi to expand
EpiPens do what
inject epineprhien straight into the blood stream
what would epipens do to BP/HR
heart rate gets faster and blood pressure raises
what would epipens do in anaphylaxis
it allows airways to relax and get bigger
PSNS and SNS run through what
the CNS (spinal cord)
severe neck/spine injury can wipe out what
sympathetic and parasympathetic nervous systems
PSNS is much sower than what than SNS
being wiped out by neck/spine injury
PSNS takes longer to dispear because
hormones linger around
neck/spine trauma often indicated by
priapism
people hanged often experience
death erection when neck breaks in execution because of PSNS overload
regions of spine top to bottom
Cervical Thoracic Lumbar Sacral Coccyx
how to find the number of neurons in the brain
dissolving the cell membrane of cells of the brain and creating a homogenous mixture of the lot. then take a sample of the soup, count the number of nuclei belonging to neurons and then scale to the overall number
M2 locations
forebrain, thalamus, heart, pupil, spinal cord, exocrine
