Control of blood pressure and volume Flashcards
What is the role of the CNS in reflex responses?
Modulate reflex responses
Initiate responses
Describe the baroreceptor reflex
Homeostatically regulates ABP
Where are baroreceptors found?
Carotid arteries
Aortic arch
Where do afferents from baroreceptors go?
To the medulla
What sort of receptors are baroreceptors?
Stretch receptors
What are responses of baroreceptor activity?
Increased sympathetic activity
Decreased parasympathetic activity
What is the effect of increased sympathetic activity?
Increased noradrenaline on a adrenoreceptors
Venous vessels constrict increasing end diastolic volume
Arterioles constrict reducing capillary hydrostatic pressure and increasing total peripheral resistance
What is the effect of decreased parasympathetic activity?
Increased noradrenaline on B1 adrenoreceptors
Increase in heart rate
Increased contractility increase end systolic volume
Increased stroke volume and increased cardiac output
What neurotransmitters are vasoconstrictors?
ADH
Angiotensin II
Where in the body does reflex vasoconstriction occur?
Skin GIT Skeletal muscle Kidney Cerebral circulation Coronary circulation
How does blood flow remain constant at different mABP?
Due to changes in arteriolar resistance
When might ABP increase?
Coughing
Sneezing
Exercising
Pain
When might ABP fall?
Standing up
Cutaneous circulation dilates heat
Haemorrhage
Dehydration
Where are volume receptors found?
In the right atrium
Where do afferents of the volume receptor reflex go?
Medulla via vagus nerve
