Short term control of blood pressure Flashcards
what is the function of elastic arteries
they give rise to medium sized vessels known as muscular arteries
what is the function of resistance vessels
they contribute significantly to the creation of the resistance to flow and regulation of blood flow
what is the valsalva manoeuvre
the action of attempting to exhale with nostrils and mouth closed
what is the function of the cardiovascular system
to circulate blood through a network of vessels throughout the body to provide individual cells with oxygen and nutrients and help dispose of metabolic wastes
why is the cardiovascular system important
circulates oxygen
removes carbon dioxide
provides cells with nutrients
what is the arterial baroreceptor reflex
it is the reflex mechanism by which baroreceptors regulate blood pressure that include transmission of nerve impulses from the baroreceptors to the medulla in response to a change in blood pressure and that produces vasodilation and a decrease in heart rate when blood pressure increases and vasoconstriction and an increase in heart rate when blood pressure decreases
what is the arterial baroreflex
it is a reflex mechanism
what do baroreceptors regulate
blood pressure
how do baroreceptors regulate blood pressure
nerve impulses are transmitted from the baroreceptors to the medulla in response to a change in blood pressure
how do baroreceptors respond to an increase in blood pressure
they produce vasodilation
decrease in heart rate
how do baroreceptors respond to a decrease in blood pressure
they produce vasoconstriction
increase in heart rate
what is the mean arterial pressure equal to
cardiac output multiplied by the total peripheral resistance
what is the pressure inside your aorta dependant on
the amount of blood being pushed into it - the cardiac output
how easy it is for your blood to get out of it - the total peripheral resistance
what is the driving force pushing blood through the circulation
the mean arterial pressure
what is a consequence of too low mean arterial pressure
fainting
syncope
what is a consequence of too high mean arterial pressure
hypertension - there can then complications with heart failure
what is the role of baroreceptors
they detect pressure
the sense pressure changes
sense general pressure
they are stretch receptors
where are baroreceptors located
there is one set in the aortic arch and another set in the bifurcation of the common carotid arteries
with regards to the aortic arch baroreceptors where do the axons travel up
the vagus nerve
what is the effect of standing on blood pressure
standing can result in increase hydrostatic pressure causing pooling of blood in veins and venules of the feet and the legs reduced end diastolic volume reduced preload reduced stroke volume reduced cardiac output reduced mean arterial pressure reduced baroreceptor firing rate reduced blood pressure
what is the response to increase the pressure when standing
the reflex response
reduced vagal tone
increased heart rate
increased cardiac output
increased sympathetic tone increased heart rate increased cardiac output increased contractility increased stroke volume increased venoconstriction increased venous return increased end diastolic volume increased total peripheral resistance
what is the result of the valsalva manoeuvre
increased thoracic pressure reduced venous return reduced end diastolic volume reduced stroke volume reduced cardiac output reduced mean arterial pressure
what is reduced mean arterial pressure detected by
baroreceptors, which initiate the reflex response resulting in increased cardiac output and increased total peripheral resistance
state 5 inputs to the medullary cardiovascular centres
cardiopulmonary baroreceptors central chemoreceptors chemoreceptors in muscle joint receptors higher centres
what are the medullary cardiovascular centres
they are part of the human brain found in the medulla oblongata
they are responsible for the regulation of the rate at which the heart beats through the nervous system and endocrine system
what are cardiobaroreceptors
they are stretch receptors that respond to blood volume
where are cardiobaroreceptors located
in low pressure bits of the circulation, e.g. walls of the atria, walls of vessels of the lungs
when are cardiobaroreceptors activated
when there is a lot of blood and high pressure, they signal a high blood pressure
what do central chemoreceptors respond to
carbon dioxide partial pressure mainly
what do central chemoreceptors stimulate
the respiratory drive
they make you breathe harder and faster and get rid of the carbon dioxide and get more oxygen
they increase heart rate and stroke volume
when are the chemoreceptors in muscle activated
when the muscle is active, the chemoreceptors increase the cardiovascular pressure response
what do joint receptors trigger
an increase in blood pressure
