I did a great deal of studying but I really need to get more done. I could use the next 5 days off along with next weekend. I used some online stopwatches yesterday to track how long I was imbued with my studies and I probably got in 9 or 10 hours yesterday - another stop watch logged the time I was not studying and just cleaning, doing laundry or washing the car and that was near 4 hours.
Anyway - I have another pic for the ECG. We still have the standard P QRS T waves along with a heart. During the P wave, the right atrias depolarized and contract, during the QRS complex the ventricles depolarize and contract, during the T wave the ventricles repolarize.
I guess I'm in decent shape for the upcoming test - I need to know exactly what ions are going into and out of the heart during each phase. The main ions are Calcium, Potassium and Sodium.
If anyone is familiar with the periodic table then they might see that Ca stands for calcium which makes sense but we also have K for potassium and Na for sodium which doesn't make quite as much sense but, sodium is called Natrium in Latin and potassium is called kalium so when we have conditions such as hyper or hypo-natremia then we are talking about high or low levels of potassium.
Hypernatremia (too much sodium) decreases heart rate
Hyperkalemia (too much potassium) decreases heart rate
Hypercalcemia (too much calcium) increases heart rate.
at least ...that's what the book says - however if you have a three-chambered frogs heart hanging from a string and add any of those elements then the heart rate seems to go all over the place and never really stabilizes although I did see beats per minute get as low as in the 20s, they just never stayed.
Ringers are used to bring the heart back to normal thumping capacity. We can have Ringers at 32 degrees celcius (room temp) or warm ...I think that was around 37 degrees celsius which is also normal body temperature or cool. Warm increases heart rate, cool decreases heart rate.
We can also have things like norepinephrine which is the neurotransmitter released by the sympathetic nervous system on the heart which will increase heart rate and then we have acetylcholine which is released by the parasympathetic vagus nerve (CN X) which slows the heart rate down.
The sinoatrial (SA) node is autorhythmic and sets a pace of about 100 beats per minute and is located in the right atrium. a couple other areas of the heart can also conduct their own rate of contraction but the area which has the highest rate sets the tone for the entire heart which is why the SA node is known as the pacemaker of the heart.
The reason most people have a resting heart rate lower than 100 beats per minute is because of the hearts innervation with the vagus nerve (CN X) which, as mentioned, is parasympathetic and slows down the rate of the heart. CN X (cranial nerve #10, the vagus nerve) is the only parasympathetic nerve going to the heart and all the rest serve to increase heart rate when necessary.
This makes me think back again to the open heart surgery and reading that heart transplant surgeons are more like plumbers than electricians becuase only the plumbing is hooked up in a heart transplant patient and I still recall a life expectancy of 10-12 years for heart transplant recipients. Contrast this with a potential 80 to 100 year life expectancy with an original heart that has all it's electrical wiring in place and we might start to suspect that the nerves play a pretty important role in the lifespan of a heart.
This also leads us back into the realm of a chiropractic adjustment - I still don't have all the physiology down for the adjustment but did learn of an initial study done in 1949 where a patient had electrodes placed along the spinous processes of their back. It was interesting to note that the spinal segments which were fixated had much higher electrical activity than those which were mobil and not fixated. Also, when pressure was applied to the fixated segments, the electrical activity increased. When pressure was applied to the non-fixated vertebral segments there was no increase in electrical activity.
Basically, the muscles surrounding the vertebrae (and there are a TON of them) are closer to their stimulation threshold when they are fixated and not able to move as they should. Another study along these lines came back in the early 1970s, circa '72 or 74 by an MD.
...checking my class notes now ...
The 1949 study was done by Denslow, I believe he was a DC and the MD in the 1970s was Barry Wyke.
Adjustments to the spine reduce sensitization - there are inhibitory effects brought on by motion - loss of motion means loss of GABA (gamma-aminobutyric acid) which (per wikipedia) is a chief inhibitory neurotransmitter in hte nervous system. It plays an important role in regulating neuronal excitability throughout the nervous system. In humans, GABA is also directly responsible for the regulation of muscle tone. ...If anyone cares to read more here's the link;
I guess something I've been realizing is that the crux of chiropractic has to do with the central nervous system (CNS) moreso than the vertebrae which are always so prominetly displayed in most offices. It makes more and more sense all the time that back pain is about 2% of what chiropractic is good for. It has much to do with keeping that little cord, the spinal cord, which is about the width of two pencil erasers, functioning optimally.
The brain and the spinal cord are the command centers for the body and from an embryological point of view, you'll notice a neural groove being formed before the heart or any other organ in the body. The neural groove is the precursor of a person's nervous system.
For this week -
Mon - Gross Anatomy II Quiz
Tue - Neuroanatomy Take home quiz and Physiology Lab due
Wed - Biochem Quiz, Microbiology Exam #3
Thurs - Physiology Exam #3
I've already completed everything for Tuesday, I worked on Gross today and answered a couple hundred questions regarding physiology over the weekend.
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