Exam 1 Flashcards
how is the orientation and planes of reference different between the midbrain and diencephalon junction
at this junction, there is a 90 degree bend, where the structures above the midbrain have the same structure as things like a lizard (so forwards is rostral, backwards is caudal, up is dorsal and down is ventral). below the junction, the spinal cord is perpendicular, so it changes to up being rostral, down caudal, anterior is ventral and posterior is dorsal)
what are the 5 functions of the NS
- maintain homeostasis
- receive sensory information/input
- integrate information
- control muscles and glands
- establish and maintain mental activity
what two structures make up the CNS
the brain and spinal cord
what structures make up the PNS
the nerves and sensory receptors
difference between afferent and efferent
afferent is sensory, so it comes in and travels to the brain, and efferent is motor, so it comes from brain to effectors or muscles/glands/etc.
the PNS has two divisions, what are they, and what are they each about? how many neurons are a part of these paths.
somatic: goes to voluntary muscles. It is a single neuron
autonomic; to smooth and cardiac muscle, and it is a 2 neuron system. (CNS to ganglion to effector)
the ANS has two divisions, what are they?
the SNS: fight or flight
the ParaNS: rest and digest.
what are some responses you see with the sympathetic NS
increased HR, blood flow to muscles, shunt blood flow from digestive system, activate muscles.
where does the split between CNS and PNS occur?
the DRG is in the PNS
what are the clinical differences between the CNS and PNS
the CNS is dermatomal and myotomal differences, whereas the PNS is going to be in a distribution pattern.
what are the five major branches of the brachial plexus
median radial ulnar musculocutaneous axillary
what are the four major branches of the lumbosacral plexus
obturator
femoral
tibial
common peroneal
what axons carry the fastest?
large and myelinated (like a alpha)
what are the slowest axons
C-fibers. unmyelinated.
what happens at the neuromuscular junction
there is a motor end plate, which at rest as a mini potential of about 0.5mV. without this you have atrophy. Then you need ACh to get an action potential going.
what part of the brain is the most rostral and advanced? what is it AKA and what is its function
cerebrum, complex function and cognition. also know as the forebrain
what are the two parts of the cerebrum
the telencephalon and the diencephalon (thalamus, hypothalamus, eipthalmus and subthalmus)
what are the components of the brainstem
midbrain (mescencephalon), pons, medalla oblongata
what happens in the brainstem
it receives sensory input, and conducts the ascending tracts to the cortex, then it is sending the motor signals out. it has all the tracts running through it. It also has the integration and control of a vegetative state, like breathing and BP.
why is damage to the brainstem life threatening
this is where the integration and control of vegetative functioning occurs, like respiration and BP regulation.
what is the cerebellum AKA and functions?
the little brain. has two hemispheres, that control eye, limb. movement, posture, balance, coordination, cognition, language, emotion.
what connects the hemispheres of the cerebellum
the vermis
the dorsal, lateral and anterior columns are in the ____ matter
white
where is the basal ganglia located
the telencephalon in the cerebrum
what is the function of the ventricles
CSF, and they allow it to travel into the SC. when backed up, there can be an enlargement in the cranium known as hydrocephaly (especially if the passage between the 3rd and 4th is blocked (cerebral aqueduct)
where are the lateral, 3rd and 4th ventricles housed
the lateral ones are in both cerebral hemispheres. the 3rd is in the diencephalon above the midbrain. and the 4th is between the medulla and the pons and the cerebellum. the pons and medulla is in front, and the cerebellum is behind.
what are the posterior, anterior and inferior horns of the lateral ventricle called
posterior: occipital horn
inferior: temporal horn
anterior: frontal horn
where is the inter ventricular (Foramen of Monro) foramen found
between the lateral and 3rd ventricle
what happens at the communication via the lateral apertures
this is the foramina of Luschka, which allows CSF to leave the ventricles (4th) and go into the subarachnoid space.
the median aperture is AKA
the foramen of Magendie (where CSF can leave the 4th)
which is contralateral, and which is ipsilateral? in terms of the cerebellum and cerebrum. what is the exception for the cerebral
cerebellum: ipsilateral
cerebral: contralateral (except the SCM, which is ipsilateral)
what are the three meninges
dura, arachnoid, (CSF) and pia.
nerves are… in the PNS
bundles of axons
ganglia are… in the PNS
bundles of neuron cell bodies
tracts are… in the CNS
collections of axons
Nuclei are… in the CNS
groups of cell bodies
a synapse is the ….
junction of a nerve cell and another cell
how do glial cells support and protect neurons
supporting their structure, makes CSF, responds to inflammation and infection, makes sheaths and gives nutrients.
what makes myelin in the CNS and PNS
CNS: oligodendricites
PNS: Schwann Cells
what are the nodes of Ranvier
they are gaps int he myelin sheaths that allow the AP to jump, via salutary conduction
what is saltatory conduction
AP jumping from node to node
what do the myelin sheaths allow for
insulating the axons, and speeding up transmission
Astrocytes
CNS: star shaped that, part of blood brain barrier. regulates the extracellular blood fluid composition, very tight junctions to be picky about what comes in and out
what are ependymal cells
in CNS, line the ventricles of the brain and central canal of the spinal cord. they secreted CSF, and helps the fluid move int he ventricles.
what are microglia:
CNS, they are phagocytic immune cells. mobile, and they are found around microorganisms, inflammation and infection and trauma. they clean shit up
Oligodendrocytes:
CNS, they make myelin around many axons (unlike Schwann cells which are around 1 axon. )
What are the glial cells of the PNS. functions?
the Schwann cells (myelin around 1 axon) and the satellite cells (around the cell bodies, protects the neurons from heavy metals- in autonomic and sensory ganglia)
how do neurons communicate
through synapses, which carry info from the axon terminals on one neuron to a post synaptic cell on an organ, neuron, gland, muscle.
Steps of an AP
- the AP reached the presynaptic terminal
- Calcium channels are opened (because of the change in the voltage), and Calcium comes into the presynaptic terminal too.
- The vesicles in the presynaptic terminal will move towards the edge, and the release site.
- The presynaptic terminal releases NT into the cleft
- The NT binds to the postsynaptic receptors
- the membrane channel will change shape, allowing the ions to enter into the cell.
what happens with postsynaptic potential? it can either be… or… which means…
excitatory: the cell membrane is depolarized, and Na rushes in, so the AP can continue
or inhibitory: the membrane is hyper polarized, meaning that you need a greater stimulus for an AP, so the AP is inhibited from continuing
what is presynaptic inhibition. what kind of synapse is it
axoaxonic synapse. one axon will release NT into the second axon. This will then inhibit/decrease what is secreted by the vesicles (NT), and inhibits the AP
what is presynaptic facilitation. what kind of synapse is it
axoaxonic. the axon releases NT into the second axon that will increase the release of NT from the presynaptic terminal, and then more will bind, so there is facilitation
what is a neurotransmitter. types?
this is what is released into he synaptic cleft, either to excite or inhibit the postsynaptic cleft. both fast and slow acting, but with one lasts fractions of a second to a minute.
what is a neuromodulator. speed? example of what it acts on?
releases into the extracellular space, and affects broad/multi neurons. acts at a distance away from he cleft. effects are slower, and last longer. This can be minutes to days, so this plays a role in gene expression.
ACh is a major transmitter in the PNS. what does it do to the skeletal muscle, ANS and the brain
skeletal muscle: initiates a contraction
ANS: slows the heart, constricts the pull, increases GI secretions and contractions.
brain: arousal, pleasure, addiction, reward, cognitive function, memory and learning.
what is the principle fast excitatory NT of the CNS, and how does it affect the brain
glutamate. its excitatory, and plays with memory and learning.
what happens if you have too much glutamate
seizures, and excitotoxicity.
What is glycine
at the spinal cord, inhibits
what is GABA
at the CNS, it inhibits, sedation, anti anxiety and seizure, sleep inducing. PRINCIPLE INHIBITOR in CNS
what happens when you do not have enough GABA
seizures and anxiety
what are the three NT/NM that are amino acids
glutamate, glycine, and GABA
what is dopamine effect on emotional system, basal ganglia, and frontal lobe
emotional: feeling of wanting a reward, so without dopamine depression.
basal ganglia: control of movement, attention, decision making, goal directed behavior
frontal lobe: thinking and planning
what is the effect of too much dopamine? not enough?
too much: schizophrenia
not enough: depression, parkinsons, ADHD
how are Parkinson’s and dopamine related:
Parkinson’s, there is a loss of dopamine receptor in the substance nigra of the midbrain.
what affects do cocaine and amphetamines have on dopamine
it prolongs the dopamine in the brain, so there is hyperactivity and euphoria.
What is NE, and how does it affect adrenal glad (SNS) and emotional system and cerebral cortex
SNS/adrenal: increased HR and force, dilation of bronchioles, inhibition of peristalsis
emotional system/ cerebral cortex: controls moot and increased attention to sensory
what happens when you have too much NE
fear and panic
what is the effect of serotonin on the CNS
regulates sleep, appetite, arousal and mood
what happens with low and high levels of serotonin
low: depression and suicide
high: OCD and schizophrenia
where does histamine affect? what part of the brain? and what does it cause at the brain
at the brain: regulates wakefulness and attention. in hypothalamus
what happens with anti-histamines
drowsy
what are the amine NT/NM
serotonin, dopamine, histamine, and NE
what are the peptide NT/NM
endogenous opioid peptides, substance P, and Calcitonin gene related peptide.
what is the effect of endogenous opioid peptides
inhibit CNS reception of pain signals. it inhibits nocioceptive signals. also gives you the runners high
what is the effect of substance P
signals tissue damage. NM, involves perception of normally innocuous stimuli as pain.
what is the effect of calcitonin gene related peptide
long term neural changes in migraine HA’s
tracts (bundles of axons in the CNS) are AKA
columns, fascicles, and lemniscus
somatosensory pathways are named for the origin and termination of the ____ neuron in the tract. give an example
second
spinothalamic. Starts in the spinal cord, and synapses in the thalamus
in somatosensory peripheral neurons, there are two axons…
the first, distal axon: from the receptor to the cell body and the second, the proximal one, from the cell body to the spinal cord or brainstem
in a somatosensory three neuron pathway, describe the locations of the first, second and third order neuron
first: receptor to spinal cord
second: cord to the brainstem or thalamus
third: thalamus or brainstem to the cortex.
what is the concept of fidelity
the degree of exactness. so there are lots of details about size, location, and intensity. it is very discriminative, and has little distraction. So spot on.
describe low fidelity
aching and slow pain that is lard to localize.
what is somatotopic organization
axons that send signals from the thumb are close to those of the hand and fingers. the homunculus
what is the primary somatosensory cortex?
the post-central gyrus on the parietal lobe
decrease the homunculus
the lower body is not he top, most medial, and as you move inferior and lateral, you get to the upper body and head and face. the bigger the parts, the more receptors and higher the fidelity.
what do mechanoreceptors, chemoreceptors and thermoreceptors respond to
mech: stretch, touch pressure, and vibration
chemo: substances
thermo: heat and temp changes.
what do nociceptors do
they pick up noxious, or tissue damage. Either actual or perceived. they lead to pain.
Pacinian corpuscle
mechanoreceptors to vibration and pressure, like an insect, really small
Meissner corpuscle
light tough
Ruffini corpuscle
stretch
Merkel cells
light touch
Free nerve endings
nociceptors.
Hair follicle receptors
light touch, movement of hair. Sensitive
Krause End Bulbs
touch, vibration and movement, but not as much
difference between tonic and phasic. which is fast and which is slow adapting
tonic: fires for the duration of the stimulus SLOW ADAPTING
phasic: constant stimulus, and stops firing while stimulus is present. So like you wear clothes, but you stop registering them and they are meaningless. fast adapting
how do receptive fields change proximally vs distally
proximally, larger, less accurate
distally, smaller, more accurate
why is there two int discrimination in the fingers
more receptors and a smaller receptor field.
why do larger diameter transmit faster
less resistance, and more myelination
what are muscle spindles
sensory organs int he muscle, have fibers, sensory ending, and motor endings. they are fusiform in shape.
what are extrafusal and intrafusal spindles
extra: skeletal muscle fibers outside of the spindle
intra: fibers inside.
what do muscle spindles respond to
stretch
in muscles spindles, what do the Type Ia and II afferents register
Type Ia: quick tonic stretch of spindle
Type II: monitor tonic stretch
what are the Golgi tendon organs
relay tension in the tendons. sensitive to small changes, ad woven into collagen.
TF: GTO’s respond to both passive and active stretch
true
what do joint receptors do
respond to deformation f the joint capsule and ligaments
what are paciniform corpuscles
respond to movement of A beta fibers,
what are ruffian’s endings
respond to extremes of joint range, and more passive movement,
what are the Type II afferent joint receptors
paciniform corpuscles and Ruffini ending
what are ligament receptors (type)
type Ib and they signal tension
what are free nerve endings? (type)
stimulated by inflammation and type III (a delta) and IV (C. fibers)
