Cardiovascular response to stress Flashcards
What is positive inotropy?
Inotropy affects the contraction of the ventricles and atria. positive inotropy increased the force of contraction thereby increases stroke volume
what is positive lusitropy?
Lusitropy is relaxation of the ventricles. Positive lusitropy increases the rate at which the heart relaxes, thereby increasing the end diastolic volume (preload)
What is positive dromotrophy?
dromotrophy affects the conduction speed in the AV node. positive dromotrophy increases the conduction speed thereby increasing the heart rate.
What does the suprarenal gland secrete that affects the vascular system?
catecholamines
where is angiotensinogen produced?
Liver
where is renin produced?
Kidney
describe the renin-angiotensin system
The RAAS controls blood pressure. When the volume of blood passing through the kidneys decreases, renin is produced (by the kidneys). This stimulates the liver to produce angiotensinogen. Angiotensinogen is activated to angiotensin 1. At the lungs ACE acts to convert angiotensin 1 to angiotensin 2. Angiotensin 2 acts on receptors to cause vaso-constriction. Angiotensin 2 also stimulates aldosterone release by the adrenal gland. Aldosterone causes water and sodium retention in the kidneys.
What are the actions of RAAS
increases central venous pressure. therefore increases the stroke volume. This leads to a greater cardiac output.
the parasympathetic system has no significant effect on …?
The RAAS and ventricular contractility
Baroreceptors regulate the autonomic nervous system. Where are theylocated?
Carotid Sinuses and Aortic Arch
what do baroreceptors respond to?
Increased arterial pressure causes increased baroreceptor firing, because pressure is high the parasympathetic innervation causes vasodilation. Decreased pressure caused decreased firing, because pressure is low the sympathetic innervation causes vasoconstriction.
