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Unformatted text preview: Finish note from Someone Finish note from Someone BIO 188 November 23, 2009 BIO 188 November 23, 2009 • Readings posted on Blackboard: 1. why mammal lungs suck 2. why bird lungs prove that Darwinism (evolution by natural selection) is wrong – say what? • Today: 1. cardiac output 2. start respiratory (gas exchange) systems 3. function, types and selective pressures on evolution 4. fish gills 5. human respiratory system functional anatomy 6. begin mechanics of ventilation What is Cardiac Output (CO)? What is Cardiac Output (CO)? • ..CO is … ..CO is … • What factors determine CO? 1. CO = • What’s stroke volume? 1. What is CO at rest? (avg. adult male) 1. CO = SV x HR 2. CO = 0.070 L/beat x 72 beats/min = 5 L/min Is CO constant? • No, of course not • Du ring strenuous exercise CO ↑↑ greatly • Difference between resting and maximal CO is called cardiac reserve 1. increases with training 2. sedentary type: maximal CO ~ 4 x resting CO 3. trained athlete: up to 7 x resting CO 1. ~ 35 L/min • What has to change to produce a change in CO? What has to change to produce a change in CO? SV ↑ automatic when end-diastolic volume ↑ • How do we regulate HR? 1. Autonomic NS and hormones! How does autonomic NS regulate HR? • .. I nnervate SA node • Human H R w/ no autonomic input = 100 b/min • To decrease decrease H R:… 1. parasympathetic parasympathetic fibers in vagus nerve vagus nerve release ACh ACh at SA node 2. heart rate (vagal tone) →↓ • How does ACh decrease heart rate? • slope of pacemaker potential in SA node ↑ How does sympathetic NS ↑ heart rate? • Sympathetic fibers release NE at SA node • ..binds to adrenergic receptors on membranes of SA node cells • H R during exercise, stress, emergency, etc. ↑ • slope of pacemaker potential in SA node ↑ Mean a rterial blood pressure = co x total resistance to blood flow through vessels What _________________________________ Gas Exchange Systems - Chapter 48 Respiration and photosynthesis require gas exchange • O 2 is required, CO 2 released as waste product in … ?...
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- Spring '08
- Evolution, Di rection, l ungs, respir atory surface, r espiratory surface