Bio 252 Exam 1 Study Questions and Correct Answers
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Course
BIO 252
Institution
BIO 252
Pulmonary circuit The right side of the heart receives deoxygenated blood from the tissues and pumps it to the lungs through the pulmonary circuit
Systemic circuit Receives oxygenated blood from the lungs and pumps it to the tissues via the systemic circuit
Heart size and location Size of a perso...
Bio 252 Exam 1 Study Questions and
Correct Answers
Pulmonary circuit ✅The right side of the heart receives deoxygenated blood from the
tissues and pumps it to the lungs through the pulmonary circuit
Systemic circuit ✅Receives oxygenated blood from the lungs and pumps it to the
tissues via the systemic circuit
Heart size and location ✅Size of a persons fist located in the mediastinum between
2nd rib and 5th intercostal space, apex sits on the diaphragm 2/3 of the mass is left of
center
Anterior to the vertebral column and posterior to the sternum
Apex is inferior base of heart is superior where the vessels come in
CPR and the heart ✅It is surrounded by two solid structures (vertebral column and
sternum, which is why you can do CPR and be able to keep the blood pumping
Pericardium ✅Double walled serous membrane
Contains 3 layers :
Fibrous layer- most superficial tough very heavy duty anchors heart to vessels and
diaphragm
Parietal layer of serous layer - outer
Visceral layer of serous layer ( which is the inner layer and is the same as the
epicardium which is also known as the outermost layer of the heart wall)
Pericardial cavity is filled with serous fluid ( between two layers of the membrane allows
heart to move friction free)
Heart Wall ✅3 layers
Epicardium - outer layer continuous with visceral pericardium
Myocardium- cardiac muscle, thick towards apex and thin towards base because pumps
are at the apex
Endocardium- continuous with endothelial lining of vessels this is the innermost layer it
lines all of the vessels and structures so when platelets come in they are not activated
Cardiac skeleton ✅Dense network of connective tissue
Provides support for the flimsy valves weak spot of the heart
Anchor for cardiac muscle cells which are short and have to hook together like a train
Insulation action potential can't go through tissues, really important for the signal to go
exact way we want the muscle to go, atria contract top down ventricles contract bottom
up only 1 signal directed very carefully
,Cardiac muscle bundles : cells arranged around the bundles all around are individual
cells, provides anchor for cells so they have something to contract against and create
force
Heart chambers ✅Four chambers
Two atria/ receiving chambers/ superior chamber
Right atrium receives deoxygenated blood from the superior and inferior vena cava and
coronary sinus
Left atrium receives oxygenated blood from the pulmonary veins
Thin walled
Seen anteriorly as auricles (like flaps deflated balloons most volume seen posteriorly
Separated by interatrial septum, very thin and plays a role in signal travel
Two ventricles/pumps
Thicker walls= more prosperous all of the power in the heart
Separated by thick interventricular septum which plays the opposite role of interatrial
septum
Walls contain traveculae carneae and papillary muscles ( huge amount of muscular
going on)
Right ventricle pumps deoxygenated blood into the pulmonary trunk
Left ventricle pumps oxygenated blood into aorta (systemic circuit)
Blood flow through the heart ✅Right Atrium > Tricuspid Valve > Right Ventricle >
Pulmonary Semilunar Valve > Pulmonary Artery > Lungs > Pulmonary Vein > Left
Atrium > Bicuspid (Mitral) Valve > Left Ventricle > Aortic Semilunar Valve > Aorta >
Body > Vena Cava
Heart valves ✅Four valves open and close due solely to pressure changes in the
ventricles
Two AV Valves:
Located at the atrioventricular junction
Right- tricuspid Left-bicuspid (mitral)
Attached to chordae tendinae
Two semilunar valves
Found at the base of the large arteries coming from the base of the heart
Right-pulmonary Left- aortic
AV Valves and Pressure ✅Av valves open when atrial pressure is greater than
ventricular pressure
Av valves close when atrial pressure is less than ventricular pressure so they are
FORCED closed by increasing ventricular pressure
Semilunar valves open ✅As ventricles contract and intraventricular pressure rises,
blood is pushed up against semilunar valves, forcing them open.
Semilunar valves closed ✅As ventricles relax and intraventricular pressure falls, blood
flows back from arteries, filling the cusps of semilunar valves and forcing them to close.
, They fall closed and must be forced open low pressure under valve in ventricle will
cause it to be closed.
Pressure affect on ventricle and opening valves ✅Change in pressure is the only thing
that opens valves
If volume increases pressure increases and opposite
If size decreases (ventricle contracts) pressure increases when the ventricle relaxes
pressure decreases
Coronary circulation ✅Supplies heart with functional blood
Right and left coronary arteries branch from the aorta, set of vessels that will supply
muscle of heart with blood that it can pull oxygen out of
Right coronary artery ✅2 major branches
Anterior - marginal artery
Posterior- interventricular artery
Left coronary artery ✅3 major branches
Anterior-anterior interventricular artery
Left anterior descending known as widow maker when its clogged because it causes a
heart attack
Around- circumflex artery (goes around the heart)
Posterior- marginal
Venous supply ✅Anterior- great cardiac vein
Posterior- coronary sinus ( 3rd vessel that feeds the right atrium that's where
deoxygenated blood from coronary circulation comes back to the right atrium so it can
get pumped out to the lungs to get more oxygen)
Cardiac muscle fiber ✅Striated and non voluntary
-cardiomyocytes - striated contract via sliding filament
-short fat branched and connected by intercalated discs ( which are very dark bands
that anchors short cells together so that they don't fall apart
-1-2 nuclei surrounded in glycogen (stores glucose)
-numerous mitochondria
-simple sr with large t tubules
Waved pattern in it increases surface area so you have more area for cell junctions to
occur on
Gap junctions allow signals to pass very quickly from cell to cell
Desmosomes connect intermediate filaments in neighboring cells
Fascia adherents connect neighboring actin filaments these two hold cell togehter
Major functional differences between skeletal and cardiac muscle ✅Cardiac muscle
does not regenerate
Stimulation: skeletal muscle used motor neurons
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