Lecture 5 Test 3 Flashcards
3 main arteries in the spinal cord
Anterior spinal artery
Left posterior spinal artery
Right posterior spinal artery
Anterior median fissure
holds the anterior spinal artery
75% of the spinal cord health is provided by the
Anterior spinal artery
25% of cord health is provided by the
Bilateral Posterior spinal arteries
The vertebral artery splits into the PICA (posterior inferior cerebelar artery), AICA (anterior inferior cerebelar artery) connects to
Posterior spinal arteries
Branches of intercostal arteries feed into…
Radicular artery, either anterior or posterior connects to the posterior and anterior spinal artery (not simultaneous)
Branching pattern of feed arteries/vessels are
irregular, varies per person
Can feed arteries come from both side and front and back of the cord?
No, it varies per person
Coronal arteries
Found on the outer surface of the cord.
Other names for Radicular arteries
Segmental arteries
Medullary arteries
4 possible pathways of cord circulation
Anterior radicular artery
Posterior radicular artery
spinal branch
Dorsal branch
Which arteries keep the rib cage healthy and perfused?
Intercostal arteries
What supplies blood to the small intestines?
Mesenteric artery
Supplies blood to the kidneys
Renal artery
Renal artery and mesenteric artery connects to the …
Aorta
Risks when performing surgery/repair/cross clamping of the aorta
Ischemia downstream from the clamping (ie. acute renal failure, spinal cord health)
How many feed arteries are found in the anterior neck/cervical area?
2 feed arteries
How many feed arteries are found in the thorax area?
2-3 feed arteries
How many feed arteries are found in the anterior lumbar area?
1-2 feed arteries
Are posterior feed arteries/vessels as important as the anterior feed arteries/vessels?
No, they don’t need as much as the anterior feed vessels.
What is the most important feed artery that provides 2/3 of arterial blood, specially lower part of the cord?
“Artery of Adamkiewicz”
the Left GREAT Radicular Artery (GRA) found in T10!!!
75% of people (range T9-T12)
Absolute Range (T5-L5)
Risk for aortic aneurysm repair?
Placement of the repair, if it’s under the GRA, you’re ok because perfusion is not affected when the aorta is clamped.
What if there’s a blockage of the GRA or the cross clamp is above the GRA?
Worried about the lower part of the being unperfused and leading to paralysis or loss of motor function post op.
Often times aortic aneurysm repair is emergent but if it’s caught earlier on what preventive measures can you do?
Imaging to see where exactly is the aneurysm or blockage. Prepare for the surgery and gather equipment (bypass machine) needed to prevent adverse effects of the surgery.
Normal perfusion pressure in the spinal cord is
50mmHg- 150mmHg
Cerebral Perfusion Pressure calculation
MAP-ICP
NML 10 mmHg
What effects does cross clamping the aorta have on the CSF (ICP)?
Raises the pressure by 10mmHg
During cross clamping procedures, how can you help lower ICP?
By placing a drain to remove CSF pressure
What is ischemia reperfusion injury?
If a Pt has been ischemic for a long time with sudden reperfusion, massive increase in blood flow and o2 to the tissues causes oxygen induced damage. Try to reperfuse slowly to prevent this issue.
Process of the corticospinal pathway
1) Motor cortex > internal capsule > thalamus > decussation of pyramids (x-over) > lateral corticospinal tract (pyramidal) > anterior horn > contract or relax based on signal
2)Motor cortex > internal capsule > thalamus > descends on same side of origination (anterior corticospinal tract) > x-over at the level of the cord > anterior horn > contract/relax
Feedback to cerebellum (sensory pathway)
Bilateral
- Posterior/dorsal spinocerebellar tract
- Anterior/ventral spinocerebellar tract
Information originates from anterior horn
What is a tract?
Bundle of axons in the CNS
Where do you receive motor sensory information from the anterior horn in the cerebellum?
Via which tract?
Anterior/ventral spinocerebellar tract into
- Superior cerebellar peduncle - Coordinate motor movements
Feedback from tendons and muscle spindle to the cerebellum to confirm contractions via (tract)
Dorsal spinocerebellar tract
into
- Inferior cerebellar peduncle
What is the cerebellum in charge of?
Complex movement
Lactic acid (Metabolic) build up, Ischemia can cause
Prostaglandins can…..
-Pain
-Augment pain sensation
Tissue pain is known as
Parietal pain
(Fast pain; A(d) fibers; localized)
Organ pain via autonomic nervous system
Visceral pain
(Appendix; difficult to localize; (c) fibers; dull/slow pain)
Point at which someone identifies pain r/t membrane potentials
Pain threshold varies per person
Due internal organs have tactile sensors?
No, but they have pain sensors
What’s referred pain?
Ex, kidney pain causes low back pain.
Soft tissues in the lungs and liver have pain sensors where?
They don’t have pain sensors
Appendix pain can cause parietal and visceral pain
“rebound tenderness” - compression makes it better.
Parietal - RLQ (sharp stabbing)
Visceral - Umbilical pain (T10) autonomic ganglia jumps 2-3 levels
Heart pain is diverted to left side of the body because
Pressure on the left side of the heart is higher than the right. Ischemia causes pain to the left side of the body.
Heartburn causes pain sensation to
upper abdomen/chest. People think they’re having a heart attack
Kidney pain referred to
Lower back pain
Limbic system is found in (3 parts)
Above the brain stem (Amygdala, hypothalamus, cingulate gyrus)
Slow pain affects what part of the brain?
Limbic system
Where do you find the cingulate gyrus?
above the corpus callossum
A fibers
Myelinated
B fiber
Lightly myelinated
C fibers
Unmyelinated
Motor neurons, muscle spindle, tendons, pressure sensors (DCML) travel through what type of fibers?
A fibers
Lateral inhibition travels through which fibers?
A (b) fibers
Aching/dull pain, nausea transmitted to what type of fibers?
C fibers
Sharp stabbing; fast pain sensors travel through what kind of fibers?
A (d) fibers
Does the brain have direct pain sensors?
No
