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Functions of cardiovascular system
- Transport
- Protection
- Regulation
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Transport
- nutrients, oxygen to cells throughout the body
- metabolic wastes to lungs & kidneys for removal
- hormones to target tissue (cells)
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Protection
white blood cells, antibodies, proteins circulate via blood and defend body against foreign microbes/toxins
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Regulation
body temperature, fluid pH, water content of cells, blood pressure
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Systemic circuits
- Carries oxygenated blood from the left ventricle to the rest of the body by the aorta
- Carries blood throughout the body
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Pulmonary circuits
- Carries deoxygenated blood from the right ventricle to the lungs by the pulmonary artery
- Carries blood to the lungs
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Describe the position of the heart in the thoracic cavity.
The heart is located in the mediastinum, which lies b/t two pleural cavities that house the lungs
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Apex
Inferior tip of heart
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Atria
- Thin-walled
- Pump blood to ventricles
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Ventricles
- Thick-walled
- Pump blood lungs (right) and body (left)
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Auricles
Extension of atria that hold extra blood
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Septa
- Divides the heart into left and right sides.
- Prevents mixing of oxygenated and deoxygenated blood.
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AV Valves
- Between atria and ventricles
- Right AV: tricuspid
- Left AV: bicuspid
- Prevet backflow of blood into the atria
- consists of cusps of dense irregular CT
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Semilunar valves
- Between ventricles and arteries
- Prevent backflow of blood into the ventricles
- Consists of 3 cusps of dense irregular CT with no muscular attachment
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What separates the ventricles
Interventricular septum
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Papillary muscles
Attach to AV cusps and contract to prevent prolapse of AV valves
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Chordae tendineae
Hold the AV vales in place while the heart is pumping blood
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Veins
- Carry blood towards heart
- oxygen poor
- flows under low pressure
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Arteries
- Carry blood away from the heart towards body
- oxygen rich
- flows under high pressure
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Coronary arteries
- Deliver blood to heart tissue
- Branches for these arrive from aortic valves
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Coronary sinus
- Drains blood from heart tissue
- returns oxygen poor blood to right atrium
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Pericardium
Double walled sac made from the membranes of the heart
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Fibrous pericardium
- thick outer layer, provides protection
- Connected to parietal layer
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Serous pericardium
: thin inner double layer
Parietal layer (tightly connected to fibrous pericardium) AND continuous with the…
Visceral layer (on top of cardiac tissue)
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Pericardial cavity
space between the two layers of serous pericardium
Filled with pericardial fluid that helps to reduce friction
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Endocardium
- Covers all inner surfaces of heart
- Composed of simple squamous epithelial tissue and underlying areolar tissue
- Forms a blood-heart barrier and protects myocardium from bacterial infection
- Blood is in direct contact
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Myocardium
- Middle, muscular layer forming atria and ventricles
- Composed of cardiac muscle
- Also includes tissue, blood vessels, and nerves
- Makes up 90% of heart wall
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Identify the major blood vessels entering and leaving the heart and classify them as either an artery or a vein and as containing either oxygen-rich or oxygen-poor blood.
- Veins; oxygen poor; carry blood toward heart
- Superior vena cava
- Inferior vena cava
- Pulmonary veins
- Arteries; oxygen rich; carry blood away from heart
- Aorta
- Pulmonary arteries
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Blood flow
- 1. Oxygen poor blood travels through the inferior and superior vena cava
- 2. Oxygen poor blood enters the right atrium
- 3. Blood passes thru the tricuspid valve which is the right AV valve
- 4. Blood enters right ventricle
- 5. Blood moves thru pulmonary valve
- 6. Blood enters pulmonary trunk and arteries where blood is carried to the lungs
- 7. Blood loses CO2 and gains O2 in the pulmonary capillaries
- 8. Oxygenated blood enters the pulmonary veins
- 9. Blood enters the left atrium
- 10. Blood travel through the the mitral/bicuspid valve
- 11. Blood enters the left ventricle
- 12. Blood moves through the aortic valve
- 13. Blood travels through the aorta and systemic arteries
- 14. Blood loses oxygen and gains CO2 in the systemic capillaries
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Right structures
Oxygen poor
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Left structures
Oxygen rich
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Explain the major factors that aid in movement of blood through the heart and produce one-way flow.
- Valves maintain direction of blood flow and prevent back flow.
- When ventricles are full, the right and left AV shut
- valves, propagation of depolarization, ventricle contraction
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Types of cardiac cells
- Working cardiomyocytes (muscle cells)
- Conductive cardiomyocytes (pacemaker cells)
Work together to cause heart contraction based on action potentials
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Working cardiomyocytes
Striated, branched, can be excited by conductive cardiomyocytes and can excite each other, can contract
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Conductive cardiomyocytes
Function in spontaneously initiating and communicating action potentials
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Intercalated discs
collection of proteins that connect cardiac cells at branch points
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Intercalated discs structural components
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Desmosomes
- Provide a physical connection
- Allows muscle cells to pull on each other without damaging membrane
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Gap junctions
- Provide cytoplasmic connection
- Made of proteins that are non-specific, leak-channels
- Allows sodium to diffuse between cells during depolarization
- Results in excitation of neighboring cells and propagation of action potentials
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Identify the parts of the conduction system in relation to the anatomy of the heart.
sinoatrial node, atrioventricular node, atrioventricular bundle and Purkinje fibers
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Conduction system
Conductive cells that initiate and help regulate heart beat
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