The cardiovascular regulation Flashcards
What is responsible for acute buffering of blood pressure?
Arterial Baroreceptors
What monitors blood acidity ? CO2, 02 , H+
Chemoreceptors
What monitors Joint movements?
proprioceptors
Where does signals in afferent path travel to?
Cardiovascular centre in medulla oblongata
What is the sympathetic nerve that increases heart rate>
Accelerator nerve
What do sympathetic Vasomotor nerves do?
Vasoconstriction
What can Noradrenaline of sympathetic also do?
smooth muscle of arterioles vasoconstrict
Where are Arterial Baroreceptors found?
Carotid sinus and Aortic Arch
Why are baroreceptors a type of mechanoreceptor?
Sensitive to stretch from increased arterial pressure
Where are afferent projections for arterial baroreceptors?
X Vagus and IX Glossopharyngeal Nerves
What are baroreceptor afferents input?
increase in Parasymp. so decrease heart rate and MAP
What does acetylcholine also do?
causes release of NO so Vasodilate
What does postural changes do ?
decrease MAP
What is orthostasis?
change to cardiovascular system when standing
What happens when standing in orthostasis?
decrease MAP and cerebral perfusion pressure so fainting
What happens in postural change?
pulse and sinus pressure decreases so decrease in carotid baroreceptor stimulation
How does Cardiovasc. centre respond to Orthostasis?
increase accelerator and vasomotor nerve stimulation so incr. MAP
What do atrial and pulmonary artery stretch receptors respond to?
lower pressures and regulate blood volume
What happens when decrease in stimulation of cardiopulmonary receptors?
ADH released so vasoconstriction so increase MAP
What does ADH cause?
incr. reabsorption of fluid from nephrons so conc. urine
What response does ADH cause?
reduce rate of glomerular filtration so increase blood volume
What effect does ADH have?
Vasoconstrictor
What is hypercapnia ?
Increased C02 in blood
What is acidosis ?
increase in H+
What can a chemoreceptor reflex be?
Increase MAP/Cardiac output via vasoconstriction
Increase rate/ depth of breathing and Tidal volume
What is cushing reaction?
Hypothalamic response to Ischemia (poor blood supply to brain)
What is response to ischemia?
increase symp.
vasoconstriction of arterioles
increase in MAP So increased blood flow to brain
How does Ischemia ( poor blood to brain) occur?
increase in Intracranial pressure where arterioles compressed so no blood supply
What is long term regulation of blood volume?
regulated by kidneys - inc. glomerular filtration will inc. urine production
What is Renin-Angiotensin aldosterone system?
Juxtaglomerular cells release renin when fall in BP
What 2 other triggers stimulate renin?
Sympathetic system
Macula Densa cells
What does renin do to angiotensinogen ?
convert to Angiotensin 1
What does Angiotensin-converting enzyme do?
convert Angiotensin 1 into Angiotensin2
What does Angiotensin 2 do?
- vasoconstrict smooth muscle
- Kidney hold more water so inc Blood vol
- Pituitary secrete ADH- does above 2 roles
- Adrenal gland release Aldosterone
What does Aldosterone do ?
Na+ retention in kidney so water reabsorbed so inc. Blood vol
Where is adrenaline and noradrenaline released?
Adrenal Medulla
What does ADH do?
increase MAP- vasoconstrictor
What does ANP do?
released by atria cells and reduces MAP
How does Atrial Natiuretic peptide reduce MAP?
Vasodilation
Excrete Na+ so low blood vol
