Summary Theory of all practicals for pathophysiology of Heart and Circulation
83 views 1 purchase
Course
Pathophysiology of Heart and Circulation
Institution
Vrije Universiteit Amsterdam (VU)
This is a summary of the theory of all practicals for pathophysiology of Heart and Circulation. With all of my summaries for this course I passed it with an 8!
Practicum 1
Expiration and inhalation test
Inhalation
• Thorax and atrial walls are stretched → stretch inhibits the of the vagal nerve
in the brainstem → sinus node → heart frequency increase
• Inside pressure: pressure in the thorax on the vein/arteries/atria decrease→
Less blood is squeezed out from pulmonary veins → go to left ventricle →
decreased stroke volume → decreased CO → MAP is decreased
• Outside pressure: pressure in the thorax on the outside of the aortic arch
decrease→ arterial wall becomes elastic → decrease the blood pressure
Exhale:
• Thorax and atrial walls are less stretched → less stretch decreases the
inhibition of the vagal nerve in the brainstem → sinus node → heart frequency
decrease
• Inside pressure: pressure in the thorax on the vein/arteries/atria increase→
blood is squeezed out from pulmonary veins → go to left ventricle →
increased stroke volume → increased CO → MAP is increased
• Outside pressure: pressure in the thorax on the outside of the aortic arch
increase → arterial wall becomes stiffer → increase the blood pressure
Air moves from high pressure to low pressure
Heart frequency is determined in the sinus node
Parasympathetic nervous system: innervate sinus node
Vagal nerve normally decrease the heart frequency
Standing up test: baroreceptor reflex
Gravity will pool the blood in the legs → limit venous return to the heart → decrease
stroke volume → decreased CO → decrease blood pressure → baroreceptors
inhibited → increase in sympathetic nervous system (connected to arterial and
venous system) activity →
1. Vasoconstriction (constriction of arterials) → increased resistance → increase
blood pressure
2. Venoconstriction (constriction of veins) → push blood back to the heart →
increased stroke volume → increased CO (and thus heart rate)→ increase
blood pressure
Increase in heart frequency: chrome tropic effect
Increase in contractile force: inotropic effect
What lowers the blood pressure?
• Nocturnal period (night) → active vagus nerve → lowers heart frequency →
lowers CO → lower MAP
• Alcohol → lower ADH → lower blood volume → decreased CO → lower MAP
• Miction (urineren) → increase in parasympathetic nervous system (contraction
of the bladder) + inactivation of sympathetic nervous system in lower body →
lower MAP
, Valsalva maneuver I
4 phases:
- Phase I: Pressure in the thorax on the vein/arteries/atria
increase but now stronger → blood is squeezed out from
pulmonary veins → go to left ventricle → increased
stroke volume → increased CO → MAP is increased
Heart rate decrease
- Phase IIa: Pressure inside the thorax is higher than pressure outside the
thorax (problem for blood vessels who have to transport blood from outside
the heart to the inside) → less blood is squeezed out from pulmonary veins →
go to left ventricle → decreased stroke volume → decreased CO → MAP is
decreased
Heart rate increase
- Phase IIb: recovery of MAP – recovery of heart rate
- Phase III: pressure in the thorax on the vein/arteries/atria decrease→ less
blood is squeezed out from pulmonary veins → go to left ventricle →
decreased stroke volume → decreased CO → MAP is decreased
Heart rate increase
- Phase IV: the venous inflow to the right ventricle is restored →
increased stroke volume → increased CO → MAP is increased
Heart rate decrease
When do you do a Valsalva → in labour, sometimes during sport
Blood pressure and posture
In lying position: blood pressure is equal in the body
In sitting position:
- Pressure in ankle is increased
- Pressure in arm stable around the same
- Pressure in ear is decreased
Pulse wave velocity
Forward (generated by contraction) and reflected (sum of lot of tiny
reflected wave generated by each branching point – long tail) wave
meet and interfere in arteries. Measured blood pressure is the sum of
these 2 pressure waves (green line)
Artery stiffen → pressure waves go back and forward quicker → come
together derived during systole → decreases in diastole lead to
decrease in filling of coronary arteries → increase risk of myocardial
ischemia
Peak of reflected wave is moved forward in time
In diastole the reflected pulse wave helps fill the coronary arteries
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller biomedicalsciencesvu. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $3.20. You're not tied to anything after your purchase.
