The Heart
ThePathwayof theBlood
Through the heart, beginning at the vena cava
anterior (inferior)vena cava is at thebottom
superior venacava is at the top
blue blood(deoxygenated) entersthe right atrium
right atrium contracts
blue blood is sentthrough the AV valveto the right ventricle
right ventriclecontracts sendingblood through thesemilunar valve outthe pulmonary artery
blood goes to thelungs
The arteries branchinto arteriolles
capillaries surroundthe alveoli in thelungs allowing theoxygen to diffuse intothe lungs
red blood returnsoxygenated to theheart through thepulmonary veins
Oxygenated (red)blood comes fromthe lungs throughthe Pulmonary VEIN
red blood enters theleft atrium
left atrium contracts
forces bloodthrough the AV valveinto the left ventricle
left ventricle is theheart’s most muscularchamber
contraction of the leftventricle sends bloodthrough the semilunarvalve out the aorta
the aorta is thelargest ARTERY inthe body
it sends oxygenrich blood to thebody
arteries branchsmaller intoarterioles andeventually intocapillaries
capillaries transferoxygen to tissues(greatest surfacearea) and extractCO2 from tissuesinto the blood
after picking upthe CO2, capillariesbecome venuolesand veins whichlead back to theheart
deoxygenated(blue) blood returnsto the heartthrough the venacava (main vein)
Quick Question?!
What is the only blood vessel inwhich diffusion can occur?
Heartbeat
Systole andDiastole phases
Lub Dub of theHeart
Diastole
relaxation wherethe atria orventricle fills withblood
Systole
ventricle or atrialcontraction toeject blood fromthe chamber
Lub Dub
lub dub is causedby the slammingclose of valves inthe heart
Systole
ventricles contractsending blood out ofthe heart
high pressure forcesthe AV valve to close
AV valves closingcause the LUB
semilunar valvesare opened byhigh pressure bloodleaving theventricles
Diastole
atria and ventriclerelax and fill withblood
low pressureopens the AV valve
Blood outside theheart causes highpressure and thesemilunar valve slamsshut
Producing the DUBsound
when the atriacontracts (atrialsystole) the blood isforced into theventricle
AV valve remainsopen and thesemilunar remainsclosed
CardiacOutput
Cardiac output is the volumeof blood pumped by the heartin one minute, which is equal tothe produce of stroke volumeand heart rate
Example
A typical human male has a stroke volume of 70mL per beatand a resting heart rate of 72 beats per minute.
a. Calculate the cardiac output. Express your answer in litersper minute.
b. Calculate the volume of blood that would be pumped inONE DAY based upon the cardiac output.
Work to Get Done!
Complete Topic 2 PracticeQuestions (pg 11 booklet)
Work on your lab write up!