A&P Test 3 Flashcards
vein follow the same or close to the same pattern of the
arteries
What is the artery in the front of the cord called?
Anterior Spinal Artery
Where does the anterior spinal artery sit?
in the anterior median fissure
What are the arteries on the back of the cord called?
Posterior lateral arteries
Where does blood come from that feeds the posterior spinal arteries?
upper portion:
vertebral arteries- found in the neck branching off of the circle of Willis
Anterior inferior cerebellar artery
posterior cerebellar artery
lower portion:
posterior radicular artery/medullary artery/segmental artery
Where do radicular/medullary artery/segmental artery arteries come from?
intercostal arteries
how many intercostal arteries do we have?
12
radicular/medullary artery/segmental artery branching is very inconsistent between
every person
Do the arteries in the spinal cord wrap all the way around the spinal cord?
no, they only go to the anterior or posterior median fissure
for every 5 or 6 levels, we might have a radicular artery coming in from the
top or bottom,
left or right
what does coronal mean?
crown
what are the coronal arteries?
the small arteries that come off the the anterior medial artery or posterior lateral arteries and branch towards the sides of the cord
If you have damage to part of the spinal cord arteries, it can be a little worse off than the brain, why?
There is no complete circle connecting the anterior spinal artery and lateral spinal arteries, so there is nowhere for the blood to take an alternative route on
What is the difference in the spinal veins vs. arteries?
there is a big medial vein on the posterior side of the cord
Where does the aorta sit on a thoracic vertebra?
on the left side of the vertebral body
what branches off of the thoracic aorta?
the intercostal arteries to feed the rib cage
what does the dorsal branch artery come from?
from the intercostal artery which comes from the thoracic aorta
Where does the spinal branch come from?
the dorsal branch artery which feeds off of the intercostal artery which comes from the thoracic aorta
At every level you have a spinal branch coming off of the dorsal branch of the intercostal artery’s, but the step after the spinal branch ______ from level to level
varies
Where does the spinal branch sit?
on top of the dorsal root ganglion
What are the options that spinal branch arteries can take?
right front or back of the cord
left front or back of the cord
What is the top part of the aorta called?
thoracic aorta
What is the bottom part of the aorta called?
abdominal aorta
what are the arteries that come off the bottom of the aortic artery on the left and right side?
renal arteries
What keeps our small intestine supplied with blood?
mesenteric artery
If you want to repair an aneurism, you have to _____ the aorta
clamp
what do you worry about when thinking of clamping the aorta?
the health of all of the organs below the aorta (like kidneys), and the health of the spinal cord below the clamping (worried about motor)
how many radicular arteries do most people have in the front of the cord in the neck?
2
how many radicular arteries do most people have in the front of the cord in the thorax?
2-3
how many radicular arteries do most people have in the front of the cord in the lumbar spine?
1-2
anterior spinal artery takes care of what percent of cord tissue?
75%
posterior spinal artery takes care of what percent of cord tissue?
25%
The Greater radicular artery feeds what?
2/3 of the lower cord
in the vast majority of patients we would expect the greater radicular artery to feed into the anterior spinal artery from which side of the cord?
left
If you had to pick a vertebra to pinpoint where the greater radicular artery feeds into the anterior spinal artery, which vertebra would it be?
T10
If you had to pick a vertebra range to pinpoint where the greater radicular artery feeds into the anterior spinal artery, which vertebra range would it be?
T9-T12
75% of people
What is the absolute range for where the greater radicular artery feeds into the anterior spinal artery?
T5-L5
what is another name for the GRA (great radicular artery?)
artery of Adamkiewicz
if you clamp below the artery of Adamkiewicz you would or would not be worried about the patient waking up paralyzed?
would not
if you clamp above the artery of Adamkiewicz you would be worried about what consequence?
the patient waking up paralyzed from under profusion of the grey matter where motor neurons are in the cord below the clamp.
What can you do before an aneurysm repair that can prevent paralyzing the patient?
Imaging like an MRI to figure out where the feed vessels, specifically the GRA or Adamkiewicz artery are
the higher the radicular artery is the ____ the aneurysm repair is
safer
normal perfusion pressure is
50-150mmHg
cerebral perfusion pressure formula
Map-ICP
normal ICP is
10mmHg
If you have a high ICP then you’re going to have more of an impediment getting normal blood flow to the
brain and spinal cord
There are certain times when CSF pressure ends up being an impediment for spinal cord _____
blood flow, especially if the MAP is low
What is the top reason to have increased CSF pressure high enough that it impedes spinal blood flow?
aortic cross clamping
aortic cross clamping can raise the CSF pressure by an average of
10mmHG or higher
What is a way to decrease CSF pressure during cross cord clamping is to
insert a drain to remove some of the CSF
If you have to cross clamp the aorta to do an aneurysm repair, what are some things you can do to help prevent the cord becoming too ischemic
- Anything that reduces inflammation in the cord
- Drugs that slow down the metabolic rate of the cord
What is ischemic reperfusion and why do we worry about it?
When a tissue has been ischemic for a long time and then you restore massive amounts of blood flow all at once (removing the cross clamp during an aneurysm repair).
When tissues are close to dying d/t ischemia, they are wide open basically begging for any blood to come through, so when you rapidly store massive amounts of blood, there’s so much blood flow and Oxygen that it damages the tissues (oxygen getting on a scratch on your car=rust)
This is hard to study because no one wants to sign off on with holding oxygen but might be better to release the clamp slowly.
what is in our body that keeps oxygen induced damage in check?
antioxidants
What is the power of oxidative potential of oxygen in the body?
the immune system uses it to destroy stuff
What is the ascending feedback loop that sends information to the cerebellum?
anterior/ventral spinocerebellar tract
posterior/dorsal spinocerebellar tract
What does the cerebellum do?
helps coordinate muscle during complex tasks, especially ones with a lot of muscles involved, like driving a car
the anterior spinocerebellar tract sends information regarding what?
level of synaptic activity in the anterior horn
There are sensors off to the side of the horn that sense how much activity is happening. If it’s motor probably a lot
tract is a
bundle of axons in the cns
the anterior spinocerebellar tract gets fed into the
superior cerebellar peduncle
what is the superior cerebellar peduncle?
a bundle of axons after it has moved out of the ventral cord and brainstem where it filters into the cerebellum
The posterior spinocerebellar tract sends information regarding what?
tendons
muscle spindles
tells the brain whether the muscles or tendon did what it was supposed to do or if the muscle was shut down by the reflex
What is the inferior cerebellar peduncle?
a bundle of axons after it has moved out of the dorsal cord and brainstem where it filters into the inferior portion of the cerebellum
prostaglandins don’t directly cause pain, they just
augment pain
How is ischemia painful?
there’s a build up of metabolic byproducts like Lactic acid and it can’t be cleared because profusion is bad
what is pain threshold?
ease of difficulty of eliciting a painful feeling
high pain threshold= high pain
tolerance
what factors into pain threshold?
genetics
environmental
if the threshold potential is exceeded, then you have an
action potential
what is parietal pain?
Tissue pain. more superficial parts of the organ
localizes very well.
what is visceral pain?
referred pain: straight organ pain that is transmitted through the autonomic nervous system which is why it is hard to localize.
What is an example of visceral pain?
feeling pain from an almost burst appendix in the umbilicus
What is an example of parietal pain?
feeling pain from an almost burst appendix in the right lower quadrant
Many of our organs don’t have tactile sensors so this means that
the organs aren’t very good at localizing pain because the DCML system isn’t being stimulated
soft tissues in our lungs do not have
the internal liver does not have
pain sensors
so you can smoke and drink for 30 years and you wouldn’t really feel it
visceral pain is more ______ where parietal pain is more _______
dull achy
sharp
what is dual pain?
both parietal and visceral pain
appendix
visceral pain: outside of the appendix: RLQ
parietal pain: inside of the appendix: umbilics
What is the path of visceral pain in the appendix?
visceral pain fibers are routed through the sympathetic chain and is fed into the autonomic ganglia then ascends 2-3 levels and enters the cord via the pain transmission pathways.
Specifically T10 (umbilical region)
visceral pain isn’t something that can be suppressed via
Why?
lateral inhibition/ physical pressure
It isn’t localized so the pain is coming from a different area in the body. Also, there aren’t any touch sensors that can laterally inhibit it.
What is the pain of decompression?
pressure on top of the appendix helps suppress pain but when you take pressure off it will hurt like hell
why don’t we have right side pain in a heart attack?
because the pressures are lower on the right side. the ischemia is typically coming form the left side of the heart
where is the limbic system found?
right on top of the brain stem
why does slow pain mess with our emotions?
because the limbic system is closer in proximity
if you think of limbic system you should think of what structures?
the amygdala
hypothalamus
cingulate gyrus
what is the amygdala?
a deep brain structure found on either side of the diencephalon that is associated with the limbic system
What is the cingulate gyrus?
a deeper gyrus that sits just outside of the corpus collosum in the middle of the brain. NOT a part of the border of the parietal or frontal lobe but IS a part of the cerebral cortex
which part of the cerebral cortex is probably connected to the slow pain system?
the cingulate gyrus
big myelinated neurons are what type of fibers?
A fibers
lightly myelinated neurons are what type of fibers?
B fibers
Non myelinated neurons are what type of fiber?
C fibers
B and C fibers are probably going to be found in the
more primative parts the nervous system like autonomic nervous system.
we don’t even realize what the ANS is doing
A fibers are thought to be more well developed or more specialized than the B and C fibers and therefore can conduct information _____
faster and more efficiently
Motor neurons are what type of fiber?
A alpha neurons for the most part
muscle spindle feedback that comes to the cord is pretty important so we tend to send that type of information up to the brain through what type of fibers?
large myelinated fibers
muscle tendons, the safety mechanisms that are built into the tendons to prevent them from being pulled from insertion sites is really important information so is sent via
large myelinated fibers
In terms of what gets fed into the DCML pathway typically can be sent on what type of fibers?
a large span from A alpha fibers to A gamma fibers
pretty much any type of pressure sensor that helps us with lateral inhibition is going to be sent almost exclusively via
A beta fibers
a beta fibers think
lateral inhibition
sharp or stabbing pain is sent through which fibers?
A delta
if you hit your hand with a hammer what order of feelings would you have?
pressure, you know it is going to hurt
pain-sharp
pain- achy this is going to mess with your head
does the cerebral cortex have pain sensors?
no, there are pain sensors leading to it, and a lot of pain sensors in the dura matter but not directly on the brain
what could give you the worst headache of your life?
if you have a CSF leak and your brain dips down in the cranium
