biol 227 Exam Study Guide Questions
with Complete Solutions
What happens when the ventricles relax? - ANS -pressure drops inside ventricles > semilunar
valves close as blood attempts to back up into the ventricles from the vessels > AV valves
open > blood flows from atria to ventricles
What happens when the ventricles contract? - ANS -AV valves close as blood attempts to back
up into the atria > pressure rises inside of the ventricles > semilunar valves open and blood
flows into great vessels
Blood flow through the heart - ANS 1-Superior & Inferior Vena Cava
2-Rt Atrium, 3-Right AV (Tricuspid) Valve
4- Rt Ventricle
5-Pulmonary Valve
6-Pulmonary Artery
7- Lungs-pick up oxygen
8-Pulmonary Veins
9- Lt Atrium
10- Left AV (Mitral) Valve (Bicuspid)
11-Lt Ventricle
12- Aortic Valve
13-Aorta
14- Body
Coronary circulation - ANS -5% of blood pumped by heart is pumped to the heart itself
through the coronary circulation to sustain its strenuous workload
- 250 ml of blood per min
,- needs abundant O2 and nutrients
Right Coronary Artery (RCA) (part of coronary circulation) - ANS -Branches off the ascending
aorta. Supplies the right atrium and sinoatrial node (pacemaker), continues along the
coronary sulcus under the right auricle, and gives off two branches of its own (right marginal
branch and posterior interventricular branch).
- Right marginal branch: supplies lateral aspect of right atrium and ventricles
- Posterior interventricular branch: supplies posterior walls of ventricles
left coronary artery (LCA) (part of coronary circulation) - ANS -branches off the ascending aorta
- anterior interventricular branch: supplies blood to both ventricles and anterior two-thirds of
the interventricular septum
- circumflex branch: passes around left side of heart in coronary sulcus
- gives off left marginal branch and then ends on the posterior side of the heart
- supplies left atrium and posterior wall of left ventricle
What is angina pectoris? - ANS - chest pain caused by inadequate flow of blood and oxygen
to the heart
- myocardium shifts to anaerobic fermentation, producing lactate and thus stimulating
pain * starving for O2
,* Pain is felt in pectoralis major muscle because neurons get confused
What is a myocardial infarction (MI)? - ANS - Occurs when the blood flow to part of the heart is
blocked and the heart muscle becomes damaged and / or dies. It is caused because of a blood
clot that blocks the coronary artery which provides oxygen to the heart.
- Atheroma (blood clot or fatty deposit) often obstructs coronary arteries
- Heavy pressure or squeezing pain radiating into the left arm
Venous drainage - ANS Most coronary blood returns to right atrium by way of the coronary
sinus which has three main inputs: great. Cardiac, posterior interventricular, and left
marginal veins
Great cardiac veins ( part of venous drainage) - ANS - Travels alongside anterior interventricular
artery
- collects blood from anterior portion of heart
- empties into coronary sinus
Middle cardiac vein (posterior interventricular) (part of venous drainage) - ANS - Found in
posterior sulcus
- collects blood from posterior portion of heart
- drains into coronary sinus
Left marginal vein ( part of venous drainage) - ANS Empties into coronary sinus
Coronary sinus (part of venous drainage) - ANS - Large transverse vein in coronary sulcus
on posterior side of heart
- collects blood and empties into right atrium
Cardiomyocytes - ANS - striated, short, thick, branched cells, one central nucleus surrounded
by light-staining mass of glycogen
, - Repair of damage of cardiac muscle is almost entirely by fibrosis (scarring)
Intercalated discs - ANS -junctions between cells anchor cardiac cells
-Interdigitating folds: folds interlock with each other, and increase surface area of contact
-Mechanical junctions tightly join cardiomyocytes
-Desmosomes—mechanical linkages that prevent contracting cardiomyocytes from
being pulled apart from each other
-Electrical junctions (gap junctions) allow ions to flow between cells; can stimulate neighbors
-Entire myocardium of either two atria or two ventricles acts like single, unified cell
Metabolism of Cardiac Muscle - ANS - Cardiac muscle depends almost exclusively on
aerobic respiration to make ATP. It is very rich in myoglobin and glycogen.
-Rich in myoglobin and glycogen
-Huge mitochondria: fill 25% of cell
- adaptable to different organic fuels: Fatty acids (60%); glucose (35%); ketones, lactate, and
amino acids (5%)
* don't run out of fuels; run out of O2 first
Conduction through the heart - ANS SA node, AV node, AV bundle (Bundle of His),
Purkinje fibers
Sinoatrial (SA) node - ANS A specialized area of cardiac tissue, located in the right atrium of
the heart, which initiates the electrical impulses that determine the heart rate; often termed
the pacemaker for the heart.
Atrioventricular (AV) node - ANS A small mass of specialized cardiac muscle fibers, located in
the wall of the right atrium of the heart, that receives heartbeat impulses from the sinoatrial
node and directs them to the walls of the ventricles.
with Complete Solutions
What happens when the ventricles relax? - ANS -pressure drops inside ventricles > semilunar
valves close as blood attempts to back up into the ventricles from the vessels > AV valves
open > blood flows from atria to ventricles
What happens when the ventricles contract? - ANS -AV valves close as blood attempts to back
up into the atria > pressure rises inside of the ventricles > semilunar valves open and blood
flows into great vessels
Blood flow through the heart - ANS 1-Superior & Inferior Vena Cava
2-Rt Atrium, 3-Right AV (Tricuspid) Valve
4- Rt Ventricle
5-Pulmonary Valve
6-Pulmonary Artery
7- Lungs-pick up oxygen
8-Pulmonary Veins
9- Lt Atrium
10- Left AV (Mitral) Valve (Bicuspid)
11-Lt Ventricle
12- Aortic Valve
13-Aorta
14- Body
Coronary circulation - ANS -5% of blood pumped by heart is pumped to the heart itself
through the coronary circulation to sustain its strenuous workload
- 250 ml of blood per min
,- needs abundant O2 and nutrients
Right Coronary Artery (RCA) (part of coronary circulation) - ANS -Branches off the ascending
aorta. Supplies the right atrium and sinoatrial node (pacemaker), continues along the
coronary sulcus under the right auricle, and gives off two branches of its own (right marginal
branch and posterior interventricular branch).
- Right marginal branch: supplies lateral aspect of right atrium and ventricles
- Posterior interventricular branch: supplies posterior walls of ventricles
left coronary artery (LCA) (part of coronary circulation) - ANS -branches off the ascending aorta
- anterior interventricular branch: supplies blood to both ventricles and anterior two-thirds of
the interventricular septum
- circumflex branch: passes around left side of heart in coronary sulcus
- gives off left marginal branch and then ends on the posterior side of the heart
- supplies left atrium and posterior wall of left ventricle
What is angina pectoris? - ANS - chest pain caused by inadequate flow of blood and oxygen
to the heart
- myocardium shifts to anaerobic fermentation, producing lactate and thus stimulating
pain * starving for O2
,* Pain is felt in pectoralis major muscle because neurons get confused
What is a myocardial infarction (MI)? - ANS - Occurs when the blood flow to part of the heart is
blocked and the heart muscle becomes damaged and / or dies. It is caused because of a blood
clot that blocks the coronary artery which provides oxygen to the heart.
- Atheroma (blood clot or fatty deposit) often obstructs coronary arteries
- Heavy pressure or squeezing pain radiating into the left arm
Venous drainage - ANS Most coronary blood returns to right atrium by way of the coronary
sinus which has three main inputs: great. Cardiac, posterior interventricular, and left
marginal veins
Great cardiac veins ( part of venous drainage) - ANS - Travels alongside anterior interventricular
artery
- collects blood from anterior portion of heart
- empties into coronary sinus
Middle cardiac vein (posterior interventricular) (part of venous drainage) - ANS - Found in
posterior sulcus
- collects blood from posterior portion of heart
- drains into coronary sinus
Left marginal vein ( part of venous drainage) - ANS Empties into coronary sinus
Coronary sinus (part of venous drainage) - ANS - Large transverse vein in coronary sulcus
on posterior side of heart
- collects blood and empties into right atrium
Cardiomyocytes - ANS - striated, short, thick, branched cells, one central nucleus surrounded
by light-staining mass of glycogen
, - Repair of damage of cardiac muscle is almost entirely by fibrosis (scarring)
Intercalated discs - ANS -junctions between cells anchor cardiac cells
-Interdigitating folds: folds interlock with each other, and increase surface area of contact
-Mechanical junctions tightly join cardiomyocytes
-Desmosomes—mechanical linkages that prevent contracting cardiomyocytes from
being pulled apart from each other
-Electrical junctions (gap junctions) allow ions to flow between cells; can stimulate neighbors
-Entire myocardium of either two atria or two ventricles acts like single, unified cell
Metabolism of Cardiac Muscle - ANS - Cardiac muscle depends almost exclusively on
aerobic respiration to make ATP. It is very rich in myoglobin and glycogen.
-Rich in myoglobin and glycogen
-Huge mitochondria: fill 25% of cell
- adaptable to different organic fuels: Fatty acids (60%); glucose (35%); ketones, lactate, and
amino acids (5%)
* don't run out of fuels; run out of O2 first
Conduction through the heart - ANS SA node, AV node, AV bundle (Bundle of His),
Purkinje fibers
Sinoatrial (SA) node - ANS A specialized area of cardiac tissue, located in the right atrium of
the heart, which initiates the electrical impulses that determine the heart rate; often termed
the pacemaker for the heart.
Atrioventricular (AV) node - ANS A small mass of specialized cardiac muscle fibers, located in
the wall of the right atrium of the heart, that receives heartbeat impulses from the sinoatrial
node and directs them to the walls of the ventricles.
