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39 Cards in this Set
- Front
- Back
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What are the 3 basic components of the circulatory system? |
Heart Blood Vessels Blood |
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Heart is a pump that establishes what? |
Pressure Gradient |
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What do blood vessels do? |
passageways in which blood flows through heart, lungs, and rest of the body |
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What is the function of blood? |
transport medium in which materials are transported, dissolved, or suspended. |
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What to systems are in the Circulatory System? |
Pulmonary Systemic |
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Pulmonary system delivers blood to and from what? |
To the lungs and from the heart. |
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Systemic system delivers blood to and from what? |
To the body and from the heart. |
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Describe the Heart |
Hollow, muscular organ Striated, mono-nucleated, Involuntary |
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Where is the Heart positioned? |
Behind sternum and vertebrae |
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The heart is known as what kind of pump? |
Dual pump |
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Does the right half of the heart function differently from the left half? |
Yes |
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Where are the four chambers of the heart located? |
The heart has four chambers. The right atrium and right ventricle are on the right side with atrium on top. The left atrium and left ventricle are on the left side with left atrium on top. |
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Where does blood travel from Superior Venae Cava to? |
Right atrium which then transports the blood into the right ventricle through the tricuspid or the also known as the right atrioventricular valve. |
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Where does blood go from the ventricles? |
Out of the heart and to the body |
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What direction does arteries carry blood? |
Away from the body |
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What direction does veins carry blood? |
From tissues to the atria |
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What is the septum portion of the heart? |
A continuous muscular portion in which it separates blood from the two sides of the heart. |
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What are the steps of the Circuit of Blood Flow? |
Venae cave brings deoxygenated blood to the right atria. CO2 is added Right atria--> right ventricle--> pulmonary artery---> lungs |
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What happens after the blood enters the lungs? |
The lungs add oxygen to the blood and CO2 is removed. After, it goes from oxygenated blood to pulmonary veins--> left atrium--> left ventricle--> aorta |
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Descrive the Atrioventricular Valves |
There are two, right and left AV valves, that are position between atria and ventricles Right AV valve is also known as tricuspid valve Left AV valve is also known as bicuspid valve Chordae tendinae are string like tendons that connect the AV valves to the papillary muscles of the ventricles. This keeps it from everting |
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What are the functions of the Atrioventricular Valves? |
Prevents back flow of blood during ventricular contraction |
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What are Semilunar Valves and where are they located? |
Semilunar valves are valves positioned at the junction where major arteries leave ventricles. There are 2. The Pulmonary Semi-lunar valve and the Aortic Semi-lunar valves.
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Why aren't there any valves between Atria and Veins? |
Atrial pressure is normally not higher than venous pressure. Sites where veneae cava enter the atria are partially compressed during atria contraction |
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When do valves open and close? |
Valves open when pressure is greater behind the valve. Valves close when pressure is greater in front of it. |
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Descrive the 3 layers of the heart wall |
Endothelium--> tissue that lines the entire circulatory system (deep, thin inner tissue)
Myocardium--> muscular tissue and middle layer made of cardiac muscle. Bulk of the heart wall
Epicardium--> thin, external layer covering heart |
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Describe Cardiac Muscle Fibers |
Interconnected by intercalated discs and form functional synocytia. |
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What two membrane junctions lie within the intercalated discs? |
Desmosomes--> holds cells together Gap Junctions--> allows action potential to pass |
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What is the electrical activity of the heart? |
Beats by autorhythmicity
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What two specialized types of cardiac cells? |
Contractile Cells Autorhymic cells |
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What are contractile cells? |
99% of cardiac muscle cells does the mechanical work of pumping Does not initiate own action potential |
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What are autorhymic cells? |
does not contract responsible for initiated and conducting action potentials for contraction of working cells |
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What non-contractile cells are capable of autorhymicity? |
Sinoatrial Node (SA Node) Atrioventricular Node (AV Node) Bundle of HIS Purkinje Fibers |
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What and where is the SA Node? |
bundle located at the top part of the right atrium near the superior veneae cava Known as the pacemaker of the heart Around 70-80 action potentials per minute |
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What and where is the Atrioventricular Node (AV Node)? |
AV node is located at the bottom right of the right atrium Specialized cells Around 40-60 action potentials per minute. |
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What and where is Bundle of HIS (Atrioventricular bundle)? |
Originates at the AV nodes and goes into the inter ventricular septum and then divide into right and left and travels down the septum where it eventually curves around ventricles and back up to atria along the outer walls
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What and where is Purkinje Fibers? |
small, terminal fibers extending from bundle of HIS spreads throughout ventricular myocardium |
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What is the pathway of the electrical activity of the heart? |
Impulse at SA Node--> travels to right and left atria--> impulse goes from right atria to ventrical VIA AV node--> action potential briefly delayed at atria (allows ventricles to fill)--> impulse travels down inter ventricular septum by means of bundle of HIS--> impulse dispersed throughout myocardium VIA purkinje fibers--> rest of ventricular cells activated by cell-to-cell spread of impulse through gap junctions |
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What is the Excitation-Contraction through Contractile Cells? |
Action potential at cardiac contractile cell Entry of small amount of CA2+ from ECF through L-type CA2+ channels releases rage amount of CA2+ from sarcoplasm reticulum through CA2+ release channel Both make cytosolic CA2+ Toponin and tropomyosin complex in thin filaments pull aside cross-bridge cycling between thick and thin filaments thin filaments slide inward between thick filaments results in contraction
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Is it possible for Heart to have summation and tetanus? |
No. This is due to long refractory period in conjunction with prolonged plate phase. This also ensures that alternate contraction and relaxation essential for blood pumping occurs. |
