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63 Cards in this Set
- Front
- Back
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Functions of the Cardiovascular System |
-Delivery (oxygen & nutrients) -Removal (carbon dioxide & waste products) -Transportation (hormones) -Maintenance (body temperature, pH) -Prevention (infection--immune function) |
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Components of the Cardiovascular System |
-Heart - serves as a pump -Blood vessels - serve as channels for transport -Blood - fluid which circulates throughout the body and serves to transports |
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Left & Right Atria Left & Right Ventricle |
What are the 4 chambers |
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Flow of blood |
Right atrium-->right ventricle through a one-way valve--> when it contracts it sends it to the lungs-->comes in the left atrium-->left ventricle-->aorta |
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Cardiac muscle/Myocardium |
-striated; has actin and myosin like skeletal muscle -has few central nuclei -has extensive capillary network -40% of cytoplasmic volume is mitochondria -specialized structures that hold muscle together and spread electrical signals 1. Desmosomes - hold cells together 2. Gap junctions - rapid AP transmission 3. Intercalated Discs |
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Cardiac Conduction System |
-the heart uses the ______ to signal contraction |
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Auto-conduction |
-Spontaneously generates its own electrical signal to contract _______ |
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72 beats per min (bpm) |
Intrinsic rate of contraction |
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Sinoatrial Node (SA) (Cardiac Conduction System) |
-Initiates impulse (pacemaker) -Located in right atrium |
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Atrioventricular Node (AV) (Cardiac Conduction System) |
-Moves impulse to ventricles -Located in wall right atria |
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AV bundle (bundle of His) (Cardiac Conduction System) |
-travels down the septum to apex -conducts impulse |
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Purkinje fibers (Cardiac Conduction System) |
-smaller divisions of fibers -spread into ventricles -very fast conduction |
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Cardiac Cycle |
-Includes all events that occur between two consecutive heart beats -all chambers of the hear undergo a period of systole and diastole during each cardiac cycle -60% of a cardiac cycle is diastole compared to 40% that is systole at rest -cycle takes 0.8 sec with a heart rate of 75 bpm |
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Systole |
contraction period of the heart |
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Diastole |
relaxation period of the heart, allows chambers to fill with blood |
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Electrocardiogram |
-a printout of the electrical activity of the heart -occurs b/c body fluids conduct electricity well -obtained by strategically placing electrodes on the skin |
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P wave |
atrial depolarization, occurs when impulse travels from SA node to AV node |
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QRS complex |
-ventricular depolarization, occurs as the impulse spreads from the AV node to the Purkinje fibers and into the ventricles |
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T wave |
ventricular repolarization |
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Resting (intrinsic) heart rate |
-60 to 80 beats per minute -30-40 bpm (highly trained) to above 100bpm (sedentary) |
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Exercise |
-HR will increase in direct proportion to exercise intensity -easy measure to use to estimate exercise intensity -will reach a "steady state" during sub maximal exercise within 10 seconds |
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Max heart rate |
220 - age |
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Stroke volume |
-volume of blood pumped/ejected from the left ventricle during systole -82ml at rest -SV = EDV - ESV |
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End-Diastolic Volume (EDV) |
volume of blood in the left ventricle at the end of diastole (after filing; just prior to contraction) |
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End-Systolic Volume (ESV) |
Volume of blood remaining in the left ventricle at the end of systole (after contraction) |
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Ejection Fraction (EF) |
% of EDV pumped out (67% at rest) |
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Arterial-Venous Oxygen Difference |
-Amount of oxygen extracted from the blood as it travels through the body -the difference between oxygenic arterial blood and venous blood (around 6 ml at rest) |
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During exercise |
-increases as more oxygen is taken from blood -have less oxygen in venous blood (arterial oxygen remains constant) |
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Cardiac Output (Q) |
-volume of blood pumped by the left ventricle per minute Q = HR x SV = beats/min x ml/beat = ml/min, or express as L/min -cardiac output is normal about 5-6 L/min at rest -May reach 20 L/min during exercise; 35 L/min in elite athletes |
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Blood pressure |
-the pressure exerted by blood on the vessel wall -usually expressed as arterial pressure |
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Systolic blood pressure (SBP) |
-highest pressure; occurs during contraction of the heart |
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Diastolic blood pressure (DBP) |
lowest pressure; occurs during "filling" |
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Mean arterial pressure (MAP) |
-average pressure exerted by the blood as it travels through arteries -MAP = DBP + [0.333 (SBP - DBP)] -estimated this way b/c the heart spends a larger amount of time in diastole |
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Functions of the blood |
1. transports gas, nutrients, and wastes 2. regulates temperature 3. buggers and balance acidity and helps to maintain the proper pH of efficient use of metabolic processes |
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Blood volume |
-varies across people -highly related to body size and state of aerobic training -5-6 liters in men and 4-5 liters in women |
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Plasma (Composition of the blood) |
-essentially water -55-60% of volume -levels can change acutely due to water loss and can also increase greatly in response to exercise training |
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Hematocrit (composition of the blood) |
-red cells, white cells and platelets -45-50% of volume |
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Red Blood cells |
-erythrocytes -constantly destroying and producing new cells -function to transport oxygen -hemoglobin -4 oxygen molecules bind to each hemoglobin -250 million hemoglobins per RBC -A RBC can bind up to 1 billion molecules of oxygen |
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The vascular system |
arteries, arterioles, capillaries, veins |
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Arteries |
carry blood away from heart to arterioles (conduits) |
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Arterioles |
-smaller branches of arteries -surrounded by vascular smooth muscle -blood passes through these into capillaries -resistance vessels |
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Capillaries |
-narrow -exchange between tissues and the blood occurs here |
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Veins |
-contrain valves that prevent back-flow of blood -most of your blood is in veins at any one time |
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Microcirculation |
-highly branched network -large arteries from heart:minimal resistance -smaller feed arteries: up to 50% of resistance |
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Arteriolar networks: major resistance vessels |
1. first order (primary) arterioles 2. second-order arterioles 3. third-order arterioles 4. fourth-order arterioles 5. terminal arterioles 6. capillaries |
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Anatomy of Resistance Vessels |
1. smooth muscle cells 2. monetary of endothelial cells lining lumen 3. plexus of perivascular sympathetic nerves |
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smooth muscle cells |
-encircle artery & arteriole lumen -contract, causing vasoconstriction & reducing vessel diameter |
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Monolayer of endothelial cells lining lumen |
-in contract with flowing blood -signal smooth muscle cells to relax |
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Plexus of perivascular sympathetic nerves |
-cover smooth muscle cells -signal smooth muscle cells to contract |
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Where blood is sent in the body |
-Normal: metabolically active tissues receive the greatest amount of blood 1. at rest the liver (27%) and the kidneys (22%) receive almost half of all the circulating blood 2. skeletal muscle receives only 15% |
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What happens to blood when exercising? |
-blood goes to the muscles (80% or more) -cardiac output and blood flow to active muscle can increase up to 25 times that at rest |
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blood distribution |
-eating: blood moves to digestive system -heat stress: blood moves to skin |
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Cardiovascular Responses to Exercise |
-increased cardiac output -increased skin blood flow -decreased blood flow to the kidneys and spleen -maintenance or small increase in blood flow to brain -increased flow to coronary arteries -increased skin blood flow |
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Cardiac Output Response to exercise |
-increases directly with increasing exercise intensity -4-5 L/min to 20-35 L/min -HR (most important) increases -SV increases: increased preload, increased contractility, decreased resistance to flow |
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Structures of the respiratory system |
-lungs -alveolus -pulmonary capillaries |
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Inspiration |
-active process of brining air into the lungs -expand the lungs, pressure inside drops, air then moves in from outside (pressure only drops a few mmHg) -during forced breathing, the pressure may fall 80-100 mmHg -thorax is expanded form inspiration |
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Expiration |
-a passive process at rest -relax muscles, ribs and sternum return to normal position -pressure in the lung increases air moves out -ribs and sternum return downward, diaphragm relaxes and is pushed upward, and lung tissue recoils |
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Functions of Pulmonary Diffusion |
-replenish oxygen in the blood -remove carbon dioxide from venous blood |
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What's needed for pulmonary diffusion |
-air: brins O2 into the lung and removes CO2 -blood: to receive the O2 and CO2 |
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Oxygen transport |
-dissolved in blood plasma (2%) -bound to hemoglobin (98%) -allows blood to transport 70 times more O2 than plasma alone -each hemoglobin molecule can bind 4 molecules of O2 |
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Hemoglobin Saturation |
-usually 98% saturated -this is higher than what our bodies require -consequently, the blood's oxygen-carrying capacity seldom limited performance |
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Ventilation (VE) |
_____ is the product of tidal volume (TV) and breathing frequency (f) |
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Ventilation and Exercise |
-Ventilation increases with exercise -phase 1 - immediate, produced by body movement (no change in chem. environment) -phase 2 - gradual, produced by changes in temp., and chemical status (chemoreceptors_ of arterial blood (CO2 and H+) -post exercise - ventilation remians elevated, must regulate pH, temp., and CO2 in the blood |
