Circulatory/Cardiovascular System Flashcards
What does a circulatory system consist of?
muscular pump (the heart), fluid (blood), and a series of conduits (circulatory vessels)
Open Circulatory System
fluid leaves the circulatory system and moves between the cells
Closed System
completely contain the fluid in a continuous system of vessels; blood is kept separate from the interstitial fluid; blood is pumped through the vascular system by one or more hearts
Advantages of a Closed Circulatory System
faster transport of materials through vessels; blood can be directed to specific tissues by varying resistance (diameter); specialized carrier and transport hormones or nutrients to specific sites
Arteries
carry blood AWAY FROM THE HEART and branch into arterioles that feed into capillary beds
Capillaries
tiny, thin-walled vessels; site of exchange between blood and tissue fluid
Venules
drain the capillary beds and form veins which deliver blood BACK TO THE HEART
Artioventricular valves
AV (tri and bicuspid valves) prevent backflow when ventricles contract
Pulmonary Semi-lunar Valve and Aortic Semi-lunar Valve
between ventricles and major arteries; prevent backflow when ventricles relax
What does the pulmonary circuit consist of?
superior vena cava, right atrium, tricuspid valve, right ventricle, pulmonary semi lunar valve, and pulmonary artery
What does the systemic circuit consist of?
pulmonary veins, left atrium, bicuspid valve, left ventricle, aortic semi lunar valve, aorta, then the body
Pulmonary Arteries
carries deoxygenated blood to the lungs
Pulmonary Veins
carry oxygenated blood back to the heart
Hepatic Portal System
blood directed from digestive system is filtered through the liver
Cardiac Cycle
each time the heart beats, the four chambers go through phases of systole (contraction) and diastole (relaxation); ventricular contraction is the driving force of for blood circulation
Systolic Pressure
is high when the heart expels blood (typically 120)
Diastolic Pressure
occurs when the heart ventricles are relaxing (typically 80)
When is speed of the blood lowest?
in the capillary beds
Intrinsic Control of Heartbeat
the electrical system of the heart; heart contractions are dictated by electrical impulses triggered by signals from the nervous system; the electrical system occurs first, follows by excitation (contraction), followed by relaxation of the muscle
Sinoatrial Node
SA node or pacemaker; initiates the heartbeat and causes the atria to contract
Where is the SA node located?
In the right atrium, towards the top part
Atrioventricular Node
AV node; conveys the stimulus and initiates contraction of the ventricles
Where is the AV node located?
In the right atrium, lower down towards the left side closer to the tricuspid valve
How/Where does the signal travel from the AV node?
travels through the atrioventricular bundle and to the smaller purkinje fibers
