ch 18 cardiovascular system- the heart 1/28 Flashcards
what is the hearts purpose
to pump and circulate blood throughout the tissues and to the lungs
pulmonary circuit of blood circulation
any of the blood vessels that carry blood to and from the lungs
pulmonary arteries
pump oxygen poor blood from the right side of the heart to the lungs to become oxygenated
pulmonary veins
pump oxygenated blood from lungs to left side of heart
which side of the heart is the pulmonary circuit on
right side. bc it pumps blood out to lungs
system circuit of blood circulation
any blood vessels that carry blood to and from the body tissues, like skeletal or skin
where does oxygenated blood leave the heart through to go to body tissues?
aorta
where does oxygen poor blood return to the heart?
superior and inferior vena cavas
what side of the heart is the systemic circuit on ?
left side, pumps blood out via aorta and oxygen gets used by tissues to then return to right side by pre/post vena cava
what is the difference between the 2 sides of the heart even tho they pump same blood volume per minute (roughly)
the pressure of the sides
right vs left side of heart and the corresponding pressure
right- low pressure, thinner walls for less contracting bc its to the lungs, so its not going very far therefore low pressure needed
left- high pressure, a lot of muscle tissue needed bc this blood goes out to entire body tissues, more pressure needed. Thick walls
gross anatomy of heart- where is it tipped
inferior tip of heart points to left hip, its tipped in the thoracic cavity- its how blood vessels attach the tip allows the flow to be more open and steady
heart is covered in
pericardium
fibrous vs serous pericardium
fibrous- outermost portion, thick and tough anchors heart in chest cavity and protects it sp bacteria can’t seep in
serous- internal portion, which is divided into visceral and parietal layers, then fluid filled sacs around heart. allows 2 layers to not rub directly agains each other
epicardium
outermost layer, visceral layer of pericardium
myocardium
middle Layer with cardiac muslce cells
MOST important and thickest heart wall, helps to generate contractions
endocardium
innermost layer, produces slick layer that covers all internal heart surfaces. allows heart to relax a bit every time it contracts and not rub against blood n heart directly
heart chambers
4 chambers, 2 atria
atrias are
superior receiving chambers, blood enters here first
right atrium
receives oxygen poor blood from systemic circuit, blood enters precava, postcava, and coronary veins
left atrium
receives oxygenated blood from lungs, so blood can enter pulmonary veins (there r two of these veins bc there’s 2 lungs)
atria features
pectinate muscle- increases contractile force of atrium without thickening atrium walls, generates the forces
auricle- two ears that sit on external surface of heart, allows atriums to receive more blood
ventricles are
inferior pumping chambers, move the pulmonary and systemic circuits and generate the most force. contractions begin at the Bottom apex, to the top of ventricle
why is it necessary for contractions to begin at bottom of heart to the top
bottom up bc blood vessels leave at the top and allows blood to move up to vessels.