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37 Cards in this Set
- Front
- Back
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Why is the heart considered a double pump? |
Pumps blood to both the lungs and the rest of the body. |
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Describe the position of the heart in the body. |
Located in the mediastinum; has broad superior base; pointed inferior apex; slightly angled to the left |
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List the layers of the heart wall from outer to inner. |
Epicardium, myocardium, and endocardium |
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List, superficial to deep, all the structures a surgeon would cut through to reach a chamber of the heart. |
Pericardial sac (fibrous pericardium then parietal serous pericardium), pericardial cavity, epicardium, myocardium, endocardium |
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What is the function for having a triple layer bag surround the heart? |
Reduces friction when the heart contracts, protects from pathogens, holds heart in position, and prevents over expansion of heart |
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Why is the left ventricle thicker then the right ventricle? |
Left ventricle is thicker because it pumps blood throughout the body (systemic circulation) while the right ventricle pumps only to the lungs (pulmonary circulation) |
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Why are the ventricles thicker then the atria? |
The ventricles require more muscle to pump to different parts of the body then the atria need to pump to the ventricles. |
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Describe the structure and function of the hearts fibrous skeleton. |
Dense connective tissue rings around and between the 4 valves; anchor valves and muscle bundles; electrically insulate atria from ventricles so they don't contract at the same time |
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List in order the parts of the electrical conduction of the heart. |
Sinoatrial (SA) node, Atrioventricular (AV) node, Atrioventricular (AV) bundle (bundle of His), Purkinje fibers |
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What are the three layers that compose the walls of arteries and veins? |
Tunica interna (intima), tunica media, and tunica externa (adventitia) |
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Describe the tunica interna (intima). |
Lines the inside of the vessel, touches the blood; made up of endothelium and a basement membrane; endothelium acts as semipermeable barrier |
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Describe the tunica media. |
Made up of smooth muscle; usually the thickest layer; has elastic (more than any other layer) and collagen fibers; prevents blood pressure from rupturing blood vessels; thickest in arteries |
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Describe the tunica externa (adventitia). |
Made of areolar connective tissue; anchors the vessel to other vessels and tissues |
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Describe arteries and their specializations |
Called resistance vessels because the are strong vessels that resist high blood pressures; has elastic layer called elastic lamina and external elastic lamina that allows for rebound and maintains blood pressure between heart beats; contractile allows for vasomotion which allows for change in the distribution and flow of blood |
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Vasodilation |
Increases the diameter of the vessel |
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Vasoconstriction |
Decreases the diameter of a vessel |
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What is the branching patterns for arteries? What happens as you go down the list? |
Aorta, conducting arteries, distributing arteries, resistance arteries and arterioles, and metarterioles; vessels lose diameter and elastic tissue and the amount of smooth muscle increases |
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What is the function and general structure of capillaries? |
Serve as exchange vessels; has only tunica interna; RBC must travel through one at a time; three types of capillaries: continuous, fenestrated, & sinusoids |
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Describe continuous capillaries. |
Most common; endothelial cells form complete ring except at intercellular clefts; pericytes are stem cells and are contractile |
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Describe fenestrated capillaries. |
Found in the kidney and small intestine; have minute filtration pores in the plasma membrane which enhance exchange of material into the blood |
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Describe sinusoid capillaries. |
Found in the liver, bone marrow, and spleen; wide, tortuous, large clefts; endothelial cells are separated by large gaps with no basement membrane; frequently have large fenstrations through them |
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Describe the branching pattern of the capillaries. |
Arteriole, metarteriole, thoroughfare channel, venule; precapillary sphincter leads to capillary bed which leads to thoroughfare channel |
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Describe veins. |
Called capacitance vessels because they can expand to accommodate an increased volume of blood; types: postcapillary venules, muscular venules, medium veins, venous sinuses, and large veins |
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Describe postcapillary venules. |
Tunica interna with minimal connective tissue and few fibroblasts, no muscle; more porous then continuous capillaries |
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Describe muscular venules. |
Thinner tunica media then arterioles, have 1-2 layers of smooth muscle; relatively larger lumen |
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Describe medium veins. |
Have all three tunics, each is thinner then arteries and less elastic; tunica externa is the thickest; have valves that prevent backflow |
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Describe venous sinuses. |
Modified veins with thinner walls, large lumens, & no smooth muscle; found in the skull & the heart |
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Describe large veins. |
Smooth muscle in all three tunics; tunica externa is the thickest; ex. vena cava
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What is an anastomoses? |
Where two veins or arteries merge without intervening capillaries; allow collateral circulation |
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What 4 arteries provide redundant supplies of blood to the cerebral circulation? |
Right and left internal carotid, and right and left vertebral artery |
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What is the function of the hepatic portal system? |
Carries blood between two capillary networks; transports absorbed nutrients from the small intestine directly to the liver for processing |
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What is the purpose of the fetal circulation? |
Deliver blood to placenta for nutrient exchange, bypass nonfunctional fetal lungs and gut |
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Foramen ovale |
Fossa ovalis in adult |
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Ductus arteriosus |
Ligamentum arteriosum in adult |
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Ductus venosus |
Ligamentum venosum in adult |
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Umbilical artery |
Median umbilical ligament in adult |
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Umbilical vein |
Round ligament of the liver |
