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Section 10.3 Regulation of Blood Flow. Pages 328-335. Heart Rate X Stroke Volume = Cardiac Output. Beats. mL blood. mL blood. =. X. min. min. beat. Examples. :. At rest:. ~ 5. 70 beats. 70 mL blood. 4900mL blood. X. =. =. liters/min. min. beat. min.
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Section 10.3 Regulation of Blood Flow Pages 328-335
Heart Rate X Stroke Volume = Cardiac Output Beats mL blood mL blood = X min min beat Examples : At rest: ~ 5 70 beats 70 mL blood 4900mL blood X = = liters/min min beat min Exercise: 13 0 beats X 70 mL blood = 9100mL blood = ~ 9 liters/min min beat min Heart Output (cardiac output) • pulse: • heart rate: number of heart beats per minute • stroke volume: • cardiac output:
Blood Pressure • the force that blood exerts on the walls of blood vessels • created by the pumping of the heart • Blood pressure is highest in the blood vessels closest to the heart (aorta), and lowest in veins • blood pressure depends on two factors: • the volume of blood pumped (cardiac output) • the resistance to blood flow caused by the narrowing of the arterioles (vasoconstriction/ vasodilation)
When left ventricle pumps out the blood Pressure rises to a MAXIMUM SYSTOLIC blood pressure When left ventricle is filling with blood Pressure falls to a MINIMUM DIASTOLIC blood pressure • Blood pressure changes as the heart beats:
Blood pressure is described by two numbers: • Example of a healthy individual: 120 means: 80 • systolic blood pressure is 120 mm Hg • diastolic blood pressure is 80 mm Hg • healthier values are usually lower, although it is possible to have blood pressure that is too low • Determining Blood Pressure: • Determined using a sphygmomanometer (blood pressure cuff) – may be done manually using stethoscope or digitally
High Blood Pressure: • Also known as hypertension • Consistent high blood pressure • Especially if systolic blood pressure rises • What causes blood pressure to increase? • Narrowing of arteries or lack of elasticity caused by atherosclerosis (arteries clogged with fatty deposits) and arteriosclerosis (hardening of arteries) • Factors that increase risk of high blood pressure: • Stress • Diet • Exercise • Genetics
Why is high blood pressure a problem? • The heart must work harder to pump blood which can cause it to enlarge and weaken • There is a increased force on the blood vessels, which can cause them to weaken and increase the risk of stroke or heart attacks • Increase chance of blood clot formation
Key Terms • Cardiac output • Stroke volume • Sphygmomanometer • Systolic • Diastolic • Hypertension • Thermoregulation • Hypothalamus
Section 10.4 Capillary Fluid Exchange Pages 336 - 339
Capillary Exchange • blood travels the following circuit: arteries ? • blood moves through capillary very slowly • this allows time for exchange of materials between blood and tissue fluid (ECF) • CO2(g) and O2(g) move in and out of capillary by process of DIFFUSION • water moves out of arteriole and carries sugar, amino acids, wastes, hormones, vitamins • these diffuse into tissue as well
Two forces control movement of fluid through capillary wall: • 1. osmotic pressure: • moves water from tissue fluid into blood • osmotic pressure constant: 25 mm of Hg (millimeters of mercury) • 2. blood pressure: • moves water from blood into tissue fluid • blood pressure is : • 35-40 mmHg at the arteriole end of capillary • 10-15 mm Hg at the venule end • somewhere in between... • solutes diffuse according to their concentration gradient • glucose and oxygen diffuse out of capillary • wastes and CO2 diffuse into capillary • proteins and RBC are too big to move out
Add Figure 1: Fluid movement into and out of the capillaries (Page 336)
Lymphatic System (p 337) • lymphatic vessels capture: • excess fluids leaked from capillaries • collect products of fat digestion (glycerol, fatty acids, and fat soluble vitamins) from small intestine • fluid is called lymph and is and dumped into veins • flows one way only • lymph vessels called lacteals are in villi in small intestine
lymph nodes (small round structures found along lymphatic system mainly in neck, groin, armpit) • filter foreign material, such as bacteria and tumor cells, • special WBC here destroy pathogens • when large numbers of bacteria or viruses are trapped in nodes, they become tender and swollen • other lymphoid organs: • Spleen - filters and cleanses blood; acts as a blood reservoir; destroys old RBC • Thymus - programs certain WBC • Tonsils - trap pathogens entering throat
Key Terms • Extracellular fluid (ECF) • Filtration • Hemorrahage • Lymph • Lymph nodes • Lymphocytes • Spleen • Thymus gland
Tasks to be completed • Read Section 10.4 in your textbook – pages 336-339 • Complete Section 10.4 Questions 1, 4-7 on page 339 • Prepare for a Chapter 10 Quiz! • Review your notes and completed textbook questions • Study and Know your diagrams! • Chapter 10 Review problems – page 346-347 • Questions 1-19 • Next up: Chapter 11 – Blood and Immunity!