Anatomy 11/8/06
Terms
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- What does the electrocariogram do and what does it contain?
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-measures electronic impulses in heart
-contains P wave, QRS complex and T wave - What does the p-wave represent?
- -atrial depolarization and contraction (systole)
- What does the QRS compelx represent?
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-ventricular depolarization and contraction (systole)
-atria repolarizes - What does the T wave represent?
- -ventricular repolarization
- What is a systole?
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-muscle contraction
-p-wave/QRS= atricular systole - What is a diastole?
- -muscle relaxation
- What happens when blood fills in right atrium and what wave occurs here?
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-stretches right atrium
-depolarizes SA node
cycle begins
-p-wave - What happens when impulse reaches AV node?
- -both atriums contrast at the sametime
- What happens after atriums contract?
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-blood pours in ventricles
-impulse splits in branches to apex - What is early Ventricle contraction and what occurs?
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-pressure in ventricle excess pressure in atrium
-shuts AV valve
-lub occures - What is late ventricle contraction and what occurs?
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-Pressure in ventricle exceed in vessels (pulmonary trunk and aorta)
-opens semi-lunar valves - What happens when ventricular contraction ends?
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-preesure in vessels exceed pressure in the ventricle
-creates back pressure - What happens when blood pour back?
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-catches flaps of semi-lunar valves and closes
-Dub occurs - What happens when heart cycle ends?
- -blood pours back into atrium and cycle restarts
- Where does blood pour in from in the right atrium?
- -from inferior and superior vena cava
- Where does blood pour out to in the right ventricle?
- -out to pulmonary trunk
- Where does blood collect from in the left atrium?
- -from lungs
- What is coronary bypass surgery?
- -To move blood past a clot using a piece of vein from the subclavian in the thigh
- What is the coronary circulation?
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-coronary arteries divide off of aorta directly after aortic semilunar valves
-coronary veins dump directly into right atrium - How do heart attacks occur?
- -caused by build-up of chorlesterol plaque in walls of coronary arteries
- What are capillaries made of?
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-one cell layer thick
-simple squamous
-sometimes has basement membrane - What are tunica intima of vein and arteries made of, contain, and do?
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-endothemlium and loose connective tissue
-has elastic laminal tissue
-keeps circulator smooth
-lines heart also - What are tunica media of vein and arteries made of?
- -smooth muscle
- What are tunica externa of vein and arteries made of and contain?
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-elastic connective tissue
-contains blood supply from minature set of arteries and veins - How are arteries and veins the same?
- -same number of layers
- How are arteries different of veins?
- -arteries have more muscle to withstand blood pressure and to create back pressures to close semilunar valves
- How are veins different from arteries?
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-have valves every 4 inches (except vena cava)
-surrounded by skeletal muscles and bulging pushes against vein (muscular massage)
-forces blood to flow up body to heart (same with lymphatic muscles) - What is the order of blood flow through the body based off of size of canals?
- -large arteries (aorta)-->small arteries--> capillarie bed--> small veins-->large veins (vena cava)
- Why do arteries have more muscle and elastic tissue?
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-For back pressure and so that blood can't go backwards
-so blood goes foreward
-closes semi-luanr valves valves in heart - How do varicose veins form?
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-valves aren't workin
-from standing on feet and pregnacies - What are capillaries attached to, what do they do, and what is the advantage of having them?
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-attached on either side by arteriole and venule
-spreads oxygen and nutrients to cells of tissues
-when a tissue is not in use, blood flow is reduced to lower stress on heart and increase longevity (120 years) - What are pre-capillary sphinchers adn what do they do?
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-circular muscle cells at beginning of capillaries
-biggest contributer to heart endurance
-when not heavily metabolizing, spinchers close and reduce blood flow
-vice-versa for metabolizing - What is normal blood pressure?
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-120mmHg / 80mmHg
-left number is systolic (contraction) measurement (blood flow stops)
-right number is diastolic (blood flow restarts)(relaxation) measurement - What are they measuring?
- -the differential b/t systolic and diastolic is what it takes to get blood into tissue
- What is the normal blood pressure for blood flowing back to the heart?
- -1-2 mmHg
- Why is there a dramatic drop in blood pressure in capiilaries?
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-no pressure due to perforations
-blood pressure ends at capillaries - What is the common carotid artery?
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-comes up each side of neck
-at around the jaw-line, bifricates into internal and external carotid - What does the internal carotid artery provide blood for?
- -to brain
- What does the cternal carotid artery prvide blood for?
- -external parts of head
- What does the jugular vein bring blood to?
- -retunrs blood from head to the brachiocephalic vein to the heart
- Where does the brachiocephalic trunk provide blood for?
- -braches off to head and arms
- What is in the carotid sinus?
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-baro and chemo receptors
-measure blood pressure to brain and CO2 content - How much of the blood supply goes to the brain?
- -20%
- Where does the basular artery receive blood from?
- -vetebral arteries (parallel to vertebral column
- Why does the circle of willis exist in the brain?
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-so blood can go all over the brain
-superior to hypothalamus (how it monitors what's going on all around your body) - What major problem may occur with internal carotid arteries?
- -enough blockage can cause a stroke
- What's good about the internal carotid arties being near the surface?
- -can do surgery easily if necessary (only if above 70% blockage)
- Why are blockages not as important in other parts of the body other than the heart, brain and liver?
- -more than one branch of blood vessels