Cardiac physiology Q6

absorbs the pressure as blood flow into the vessels which prevent a sharp rise in pressure in the vessel.

its important between heart beats, to allow blood to continue to flow as it puts pressure inside the vessels.

-they do expand during ventricular contraction as blood is being ejected into arteries (semi-lunar valve open)>aorta and arteries expand and store pressure in elastic walls.

• they do recoil during isovolumic ventricular relaxation as semi-lunar valve shut to prevent backflow of blood into ventricles> elastic (recoil) of arteries send blood forward into the circulatory system.

<p>autonomic mechanism hormonal mechanism</p> Signup and view all the answers

<p>a baroreceptor (sensitive sensory nerve root endings) located in the carotid sinus and aortic arch)&gt; decrease heart rate and arterial pressure.</p> Signup and view all the answers

<p>renin-angiotensin-aldosterone mechanism.</p> Signup and view all the answers

<p>contraction of smooth muscle in the vessel walls&gt; narrowing of the lumen&gt; increase the resistance of blood vessels to blood flow.</p> Signup and view all the answers

<p>the sympathetic nerve activity and the hormone angiotensin II.</p> Signup and view all the answers

<p>relaxation of smooth muscles and the vessel walls&gt;widen the lumen of vessels&gt;decrease the resistance of blood vessels to blood flow.</p> Signup and view all the answers

<p>caused by withdrawal of sympathetic nerve activity and locally released chemicals eg lactic acid.</p> Signup and view all the answers