circulatory system

what does the human circulatory system need?

heart → constantly pumping + dynamic, with contractile cells

way to collect consistent vol of blood

way of pumping deoxygenated blood

circuit to direct oxygen → organs

what kind of circulatory system do mammals have?

double circulatory system

why do mammals have a double circulatory system?

endothermic body temp must be maintained → high metabolic demand + oxygen demand. no mixing of blood.

why do the atriums and left/right ventricle look/function differently?

different embryonic origins

what does the left ventricle stem from?

first heart field

what does the right ventricle stem from?

second heart field

what are the key differences between systemic and pulmonary system within the human heart?

what is the equation for blood flow, Q?

Q = V x CSA

what does the vascular system consist of?

arteries

arterioles

veins

venules

capillaries

what are the key differences between arteries and veins?

what can endothelial dysfunction be caused by?

infection

injury

inflammation

genetic risk factors

cancer

thrombosis

what dies endothelial dysfunction lead to?

angiogenesis

increased vascular permeability

increased leukocyte adhesion

when do vascular smooth cells switch phenotype?

under conditions of repair

what is a key feature of de-differentiated smooth muscle cells?

narrowed vessels, causing increased blood pressure

what is pulmonary hypertension?

elevated pulmonary pressure → right heart failure

why is an increased refractory period during contraction important?

for rhythmic beating

what is the equation for cardiac output, CO?

CO = HR x SV

which nodes does the parasympathetic pathway input to during the cardiac cycle?

SA and AV

which nodes does the sympathetic pathway input to during the cardiac cycle?

SA

AV
ventricular myocardium

what effect does sympathetic simulation have on heart rate?

increases HR

what effect does acetylcholine have on the production of cAMP?

decreased production

what effect does adrenaline/noradrenaline have on the production of cAMP?

increased production

what is diastole?

dilation

heart chambers fill with blood

bp decreases

what is systole?

contraction

blood ejected from chamber

bp increases

what is end systolic volume?

amount of blood retaining in the ventricle at the end of systole, after the heart has contracted

what is end diastolic volume?

amount of blood in the ventricles before the heart contracts

what is the equation for stroke volume, SV?

SV = EDV - ESV.

what is preload?

extent of force by which heart muscle fibres are stretched by blood before the onset of systole

what is afterload?

force against which the ventricle contracts to eject blood during systole

what is the equation for mean arterial pressure, MAP?

MAP = CO x TPR

what is mean arterial pressure?

the driving force for blood flow

where are the major sites for systemic resistance?

arterioles