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Wright BIO 1150 - Circulation

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BIO 1150 1st Edition Lecture 8 Current LectureCardiovascular system-carries blood throughout body- Heart- Blood vessels- BloodLymphatic system- Lymph vessels- LymphGeneral Functions of Circulatory System- Long distance bulk transport- Overcome limits of diffusion (diffusion is too slow for survival)- Transports: gases, nutrients, waste, products, immune components, heatHow the circulatory system provide flow through the body- Pumps- applies pressure (concentration gradient)- Flow pathways (tubes)Heart= pump-applies pressure (heart is made of muscle)- 2 atria- 2 ventriclesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Epicardium- Myocardium- EndocardiumHow the heart beats- Atriol and ventricular diastole- Atriol systole- Ventricular systole- Blood flows out of the heartSmooth muscle- surrounds organs- Squeezes vessels when heart is relaxingHow blood flow works when moving upward (defying gravity)- Blood enters a chamber of the blood vessel and the bottom valve closes- Skeletal muscle squeezes chamber forcing blood up- Blood flows into next chamber and repeatsBlood flows from respiratory surfaces to tissuesHow Gills Work (note: fish have 2 chamber hearts)- The gills absorb oxygen- The heart pumps blood directly through gills- Blood directly absorbs oxygenThe fish’s blood flow system is not sufficient for our fast metabolism, that’s why we have blood flow coming to and from four different directions to the heart- Systematic circuit- high oxygen content blood to the body- Pulmonary circuit- low oxygen content blood to the lungs- Left ventricle pressure is greater than right ventricle pressure- Blood vessels resist blood flow more than lungsElectrical signals coordinate cardiac contraction- SA node-sets off signal (the pacemaker)- Ion flow helps contraction- positive ions entering triggers contraction- Electrical signals spread from cell to cell- Signal order: SA node, atria, delay, ventriclesCoordination of the beat- Contraction begins in right atria – the pacemaker cells in the SA node - Contraction spreads across atria- gap junctions (a type of pathway between cells) act as a conductor of electricity between cells- Contraction spreads to ventricles- Purkinje Fibers (behave like nerves) conduct electricity, the time delay makes sure that the ventricles contract after the atria.- Contraction spreads across ventricles by gap junctionsPressure drives blood flow through available pathways- Open circulatory system- no “tubes,” blood flows into cavity with hemolymph then seepsinto organs- Closed circulatory system (associated with the scientist, Harvey) - blood vessels flow intoorgans- Blood pressure drops as it strays farther from the heart- Smooth muscle controls vessel diameter- Change in vessel diameter regulates blood flow- More blood flow=more blood vessels- Valves- prevent reverse flow against pressure gradient- Capillaries- no smooth tissue, exchanges materialBlood pressure regulated by negative feedback- Baroreceptors- act as a blood pressure sensoro Send signals to heart or blood vessels- Blood Pressure= cardiac output x peripheral resistance- Cardiac output (mL/min) = heart rate (beat/minute) x stroke volume (mL/


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