Biology 200B 1st Edition Lecture 14Chapter 45 Circulatory SystemI. Circulatory systemII. Lymphatic systemIII. CirculationIV. Cardiac cycle and blood pressureCirculatory SystemOpen circulatory system: hemolymph confined to vessels; direct contact with tissueClosed circulatory system: blood flows in circuit; confined to vesselsBlood vessels - “infrastructure” of circulatory system-built of layered tissues: endothelium, smooth muscle, connective tissueArteries - thicker, more elastic and muscular walls than veins-accomodate high pressure of blood-pumped from heartVeins - thinner walled-muscle action pumps blood flow back to the heartCapillaries and blood pressure-very thin endothelium facilitate the exchange of materials-blood pressure and velocity of blood varies throughout circulatory system -blood distribution in capillary beds regulated by:These 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.1. contraction of smooth muscle in arteriole wall constricts the vessel2. precapillary sphincters control flow f blood between arterioles and venules3. neurons innervate sphincter musclesLymphatic system: tubules filled with interstitial fluid (lymph) that drain into large veins entering heart-plays big role in immune system-lymph nodes - filter lymph and help in body’s defensesSingle vs. Double CirculationMammalian heart and circulation-pulmonary circulation-systemic circulationHeart beat is autogenic (does not require stimulus from nervous system)Sinoatrial (SA) node: location of pacemaker cellsAtrioventricular (AV) node: delays signal prior to ventricle contractionNervous and endocrine systems direct affect heart rate and rhythmCardiac cycle and blood pressureSystolic pressure - when heart beatsDiastolic pressure - when heart rests between beatsHypertension - above normal blood pressure (consistently)Barorecptors - detect decreases in bpLow bp: -increase heart rate-increase stroke volume-arterioles direct blood away skin and intestines-constrict veinsCardiovascular disease:Heart attack - death of cardiac muscle tissue-blockage of coronary arteryAtherosclerosis - build up of
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