Nervous system + Hormones Flashcards
Give the equation for calculating mean systemic arterial pressure.
MAP = diastolic pressure + 1/3 (systolic pressure -diastolic pressure)
MAP = DP + 1/3 (SP - DP)
Which part of the brain houses the cardiovascular centre?
Medulla
Which region of the cardiovascular centre is responsible for raising blood pressure?
Pressor region - sympathetic
How does the pressor region increase blood pressure?
Pressor region > Sympathetic route > medulla > spinal cord > synapses at T1-T2 > Heart
Increases blood pressure by increasing vasoconstriction, increasing cardiac output (increasing heart rate and stroke volume) and increasing contractility.
Which region of the cardiovascular centre is responsible for lowering blood pressure?
Depressor region - parasympathetic
How does the depressor region decrease blood pressure?
Depressor region > medulla > vagus nerve > heart
Where are the cardiopulmonary baroreceptors located?
Atria, ventricles, pulmonary artery
When the cardiopulmonary baroreceptors are stimulated, what effects are made on blood pressure?
- Inhibition of pressor region, decreasing blood pressure
- Inhibition of renin-angiotensin + aldosterone system. Decreases blood pressure as angiotensin II causes vasoconstriction and increases blood pressure
- Inhibits vasopressin (ADH) to promote fluid loss as fluid increases blood pressure
Which type of blood vessel provides the most resistance to vascular flow?
Arterioles.
Name the hormone released by endothelium cells which causes vasoconstriction.
Endothelin-1
Why does hypoxia lead to vasodilation?
Hypoxia = O2 decrease. Vasodilators will dilate vessels to increase local blood flow.
Name some vasoconstrictors.
Angiotensin II, vasopressin, adrenaline
Name some vasodilators.
Atrial natriuretic peptide, adrenaline
Where are the peripheral chemoreceptors found?
Aortic arch
Carotid sinus
Where are the arterial baroreceptors found?
One is in aortic arch
Two are in carotid sinus
Describe the pathway from the baroreceptors to decreasing blood pressure.
Carotid sinus > sinus nerve > glossopharyngeal > medulla > decrease in sympathetic tone, increase in parasympathetic tone > decrease in blood pressure
Give the definition of intrinsic autoregulation.
When the arterioles vasoconstrict or vasodilate in response to changes in resistance. Aims to maintain constant blood flow.
Which neurotransmitter controls parasympathetic stimulation via the vagus nerve?
Acetylcholine, binds to muscarinic receptors
Give the effects of increased parasympathetic stimulation.
Decreases heart rate
Decreases force of contraction
Decreases cardiac output
Which neurotransmitter controls sympathetic stimulation via the accelerans nerve?
Noradrenaline + adrenaline
Give the effects of increased sympathetic stimulation.
Increases heart rate
Increases force of contraction
Increases cardiac output
