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61 Cards in this Set
- Front
- Back
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What are the 3 components of the cardiovascular system? |
blood arteries, veins, capillaries the heart |
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Describe the role of arteries, veins and capillaries in the cardiovascular system |
- arteries carry blood away from the heart -veins carry blood back to the heart -when an artery reaches an organ it branches out into capillaries and gas exchange occurs at the tissue of level across the walls of the capillaries -the capillaries then join up to form veins |
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what is the name of the sac that surrounds the heart? |
pericardial sac
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Where do you find the visceral pericardium? (serous pericardium) |
-fused to the heart (to remove, you have to rip it off) -lines the organ |
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Where do you find the parietal pericardium? (serous pericardium) |
-around the pericardial cavity and secretes pericardial fluid (transidate) -lines the walls of the pericardial cavity |
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What is the function of pericardial fluid? |
-reduces friction within the pericardium by lubricating the epicardial surface allowing membranes to glide over each other with each heart beat -allows for visceral & parietal pericardium to rub against each other but not have friction |
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What is the fibrous pericardium made of? |
-dense CT -inextensible, does not stretch, has collagen -ex: like a canvas bag w/ 2 layers (one tough, the 2nd is slick) |
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What is the fxn of the fibrous pericardium? |
-fused to the central tendon of the diaphragm so when diaphragm flattens out, the heart is pulled down and when the diaphragm dome upward, the heart moves up |
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What do phrenic nerves in the loose CT of the pericardial sac innervate? |
-they innervate the diaphragm -paired |
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What does the heart lie in? |
-fibrous pericardium (inelastic, dense CT) -tough, inextensible CT sac -continuity btw tunica adventitia of great vessels and fibrous pericardium |
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What surfaces do serous membrane line? |
- inner surface of the fibrous pericardium (parietal pericardium) -outer surface of the heart ( visceral pericardium) -pericardial cavity w/ pericardial fluid intervenes btw parietal and visceral pericardium |
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What are the 3 layers of the heart? |
-epicardium (most superficial)= visceral pericardium -myocardium= thickest layer -endocardium (deepest)= line heart chambers |
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What is each of the heart wall layers made of? |
-epicardium: mesothelium, loose areolar CT -myocardium: cardiac muscle, CT, BV & Ns -endocardium: endothelium & loose areolar CT, simple squamous, continuous with tunica adventitia of great vessels as it leaves the heart |
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What is the difference between pulmonary and systemic circulation? |
-pulmonary circulation is the circuit through the lungs where blood is oxygenated -systemic circulation is the circuit through the rest of the body to provide oxygenated blood |
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Atria vs. ventricles |
-atria= input -ventricles= output |
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What is the function of atrioventricular valves? |
-controls direction of blood flow from atria to ventricle and prevent back flow of blood from ventricles into atria during systole |
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What is the function of the semilunar valves? |
--allow blood to be pumped into the major arteries but prevent back flow of blood from arteries into the ventricles |
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What does the presence of inter ventricular sulcus (IV sulcus) indicate? |
- surface feature that indicates location of septum in an intact heart |
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What are the functions of interatrial septum and inter ventricular septum? |
-interatrial septum separates atria -interventricular septum separates right and left ventricle |
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What is the function of the atrioventricular sulcus? (AV sulcus) |
- it is another surface feature indicating the boundary btw atria and ventricles and also the location of the fibrous skeleton of the heart |
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What are the functions of the fibrous skeleton? |
-attachment for valve flaps (cusps) -attachment for myocardium -electrically insulates ventricular myocardium from atrial myocardium (to avoid spreading of impulse as we want atria to contract first to push blood into ventricles, then ventricles contract after to push blood into efferent vessels) |
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What is the name of the artery that carries blood from the left ventricle to the body? |
-aorta, carries oxygenated blood from left ventricle of the heart into systemic circulation |
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What are the branches of the aorta? |
-ascending aorta (branches to heart itself, coronary arteries) -arch of aorta (branches to head and arms) -descending aorta (branches to thorax, abdomen, legs) |
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What are the 3 branches of the arch of aorta? |
-brachiocephalic trunk -left coronary -left subclavian |
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What is the function of the ductus arteriosis in fetal circulation? |
-one of the way for blood to bypass pulmonary circulation, that occurs only in the fetus -shunts blood from right side of the heart into arch of aorta as blood arriving from placenta is already oxygenated -the ductus arteriosis is open during fetal life as the pressure is higher in the right side of the heart than left side |
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What is the ligamentum arteriosum? |
-connects pulmonary trunk (R&L arteries) to ascending aorta - it is a remnant of fetal circulation (used to be ductus arteriosis) -at time of birth, when lungs expand, pressure drops in the right side and ductus arteriosis (DA)collapses and blood will go towards the lungs hence DA will close and become scar tissue |
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What is the name of the artery that carries blood from the right ventricle to the lungs? |
The pulmonary artery carries deoxygenated blood from the right ventricle into the lungs for oxygenation, the pulmonary veins carry oxygenated blood from the lungs into the left atrium to be returned to systemic circulation |
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What are the inputs to right atrium? |
-sup and inf vena cave are 2 of the 3 inputs to R atrium -cardiac vein |
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What is the sulcus terminals? |
-surface feature of the heart -line of fusion btw 2 embryological origins that come together to form right atrium |
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How are the right and left pulmonary arteries formed? |
-formed by bifurcation of pulmonary trunk and lead to pulmonary circulation in lungs -R and L pulmonary arteries are output from R ventricle |
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Where is the base of the heart located? |
-base of the heart is posterior and the apex of the heart is always opposite of the base -4 borders of the heart (sup, inf, left and right) |
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Internal features of the right atrium and left ventricle: What happens when there is an obstruction in the right atrium? |
-blood will be shunted from the body wall and will return by inf vena cava |
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What structures do sup. vena cava drain blood from? |
-drain structures superior to diaphgram; head, brain, upper limbs |
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What is the fossa ovale? |
-it is a remnant of foramen ovale (another shunt present only in fetal circulation) -it is a depression on the right atrium |
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What is the function of foramen ovale? |
-another way to shunt blood away from right side of the heart -opening in the intertribal septum (separation btw R and L atrium), guarded by a flap valve (swinging door), if pressure in the R atrium is higher than L atrium then flap will open and blood is shunted to the left side of the heart
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Function of foramen ovale continued |
-highly oxygenated blood coming from placenta goes straight to right atrium via inf vena cava and arrives at right atrium-->foramen ovale -so due to higher pressure in the right atrium during fetal life, the blood will flow into the atrium and out of the aorta, straight into systemic circulation thus bypassing the lungs |
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Where is the SA node located? |
-at the apex of crista terminalis |
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Features of the right ventricle |
-R atrioventricular valve cusps -chordae tendineae -papillary muscles -trabeculae carnae -septomarginal or moderator band -conus arteriosis -pulmonary semilunar valve |
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What portion of the atrioventricular valves connect to papillary muscles? |
-papillary muscles are finger like projections from the wall of the ventricles, they connect the chordae tendineae (heart strings) to the cusps of the atrioventricular valves |
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Internal features of the left atrium &ventricle |
-left atrium is mostly smooth -L atrioventricular valve cusps -chordae tendineae (more coarse and larger on LS, anchors atrioventricular valve cusps to papillary muscles) -aortic semilunar valve |
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Comparison of left and right ventricle |
-left ventricle has a thicker wall as it needs to overcome entire resistance of systemic circulation so it has to generate a lot of pressure whereas the right ventricle only pumps blood from the heart to the lungs |
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What happens during systole? |
-contraction of muscle wall, increase in pressure within chamber -when heart contracts, blood pressure peaks
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What happens during diastole? |
-relaxation of muscular wall and decrease in pressure within chamber -when heart relaxes, pressure drops |
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What happens during atrial diastole/ventricular systole? |
-decrease in p in the atrium -AV valve closed, pressure in ventricle increases and contracts (walls push inwards) -semilunar valve open, blood goes into pulmonary trunk or aorta |
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What happens during atrial diastole/ventricular diastole? |
-pressure in ventricle will drop after bolus of blood has been pushed out so semilunar valve is forced shut and blood can either go out into pulmonary trunk or into systemic circulation -pressure in efferent vessel increases |
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What happens during atrial systole/ventricular diastole? |
-pressure in atrium increases (walls push inwards) -AV valve open and pressure in ventricle will gradually increase as it fills up with blood -semilunar valve is shut |
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What is the function of the semilunar valve? |
-exposed to blood when closed, will allow blood flow into coronary artery |
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What is the function of coronary arteries? |
-supply oxygenated blood from the aorta to heart muscle -branch from ascending aorta, openings behind flaps of aortic valve in sinuses
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Where is the right coronary artery located? |
-runs in AV sulcus -supplies walls of R ventricle, R atrium and ends at post IV A in post IV sulcus (change of name due to change of location) which will then supply post 1/3 of IV septum |
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Where is the left coronary artery located? |
-bifurcates forming ant. IV A (in ant IV sulcus) and circumflex A. in IV groove |
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What structures do the left coronary artery supply? |
- ant IV A ends in arterial anastomosis w/ post IV A at apex of heart and supples ~ ant 2/3 of IV septum -circumflex A. supplies walls of L ventricle & atrium and it ends in arterial anastomosis w/ R coronary artery |
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What do cardiac veins do? |
-return deoxygenated blood to right atrium via coronary sinus -great cardiac vein, middle cardiac vein and small cardiac vein |
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Where is the great cardiac vein located? |
-in ant IV sulcus, then AV sulcus -ends as the coronary sinus |
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Where is the middle cardiac vein located? |
-in post IV sulcus , empties into coronary sinus |
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Where is the small cardiac vein located? |
-in AV sulcus, empties into coronary sinus |
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The conduction sys of the heart |
1. SA node contains pacemaker cells that spontaneously depolarizes to threshold and impulse travels via internodal pathways in walls of atria to AV node, atrial myocardium contracts and there is a delay of impulse 2. fibrous skeleton prevents spread of impulse so isolates ventricular myocardium from atrial depolarization |
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The conduction sys of the heart (2) |
3. AV bundle and R, L bundle branches conduct signal thru IV septum to apex and Purkinje fibres distribute signal to myocardium of ventricular walls (wave of ventricular contraction spreads from apex to base of the heart) |
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Autonomic modulation of the heart |
-pacemaker cells of the SA node set the basic HR, force of contraction -ANS innervates SA & AV nodes and myocardium -brainstem cardiac centres control ANS input to the heart -cardiac centres adjust ANS activity to maintain BP, gas conc optimum
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Role of SyNS and PSyNS in determination of heart rate |
- SyNS increase HR thru release of NE -PSyNS decrease HR thru release of ACh |
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What Rs does the heart receive feedback info from? |
-baroreceptors (BP) -chemoreceptors ([O2]. [CO2]) |
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Companion arteries and veins |
Right coronary A = Small Cardiac V And Circumflex sort of riding along Coronary Sinus |
