Why is the respiratory system and circulatory system called a coupled unit?
the respiratory system adds oxygen and removes carbon dioxide from the blood, while the circulatory sytem is responsible for the delivery of oxygenated blood and nutrients to tissues in accordance with their needs.
2 major adjustments of blood flow during exercise
-increased cardiac output.
-redistribution of blood flow.
creates pressure to pump blood.
carry blood AWAY from the heart
exchange of O2, CO2, and nutrients with tissues
carry blood TOWARD the heart
why is the circulatory system considered closed?
because arteries and veins are continuous with each other through smaller vessels.
the 4 chambers of the heart
the purpose of the 4 valves of the heart
to prevent backflow
right side of heart
pumps deoxygenated blood to the lungs through the pulmonary arteries.
returns oxygenated blood to the left side of the heart via pulmonary veins.
left side of heart
pumps oxygenated blood to the whole body via arteries.
returns deoxygenated blood to the right side of the heart via veins.
-the heart wall
-receives blood supply via coronary arteries
-myocardial infarction (MI)
the 3 layers of heart wall
epicardium (outer layer)
myocardium (middle layer)
endocardium (inner layer)
-blockage in coronary blood flow results in cell damage.
heart muscle that is responsible for contracting and forcing blood out of the heart
pressure in ventricles rises.
ejection of blood (2/3)
shorter at rest and during exercise.
pressure in ventricles is low
filling with blood.
longer at rest, shorter during exercise.
factors that influence arterial blood pressure
determinants of mean arterial pressure (MAP)
short term regulation (sympathetic nervous system)
long term regulation (kidneys)
sinoatrial node (SA node)
pacemaker, initiates depolarization.
atrioventricular node (AV node)
passes depolarization to ventricles.
brief delay to allow for ventricular filling.
steps of conduction system
a recording of the electrical changes that occur in the myocardium during the cardiac cycle.
ventricular depolarization and atrial repolarization
which segment indicates myocardial ischemia?
fatty plague that narrows coronary arteries.
reduces blood flow to myocardium (myocardial ischemia)
-the amount of blood pumped by the heart each minute.
-heart rate x stroke volume (amount of blood pumped per heartbeat)
cardiac output increases due to:
increases in heart rate
increases in stroke volume
end diastolic volume
-dependent on venous return
venous return increased by:
venoconstriction (via SNS)
skeletal muscle pump (push blood back toward the heart)
respiratory pump (changes in thoracic pressure pull blood toward heart)
liquid portion of blood, contains ions, proteins, hormones
red blood cells
contain hemoglobin to carry oxygen
white blood cells
important in preventing infection
important in blood clotting
percentage of blood composed of cells. 42%