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Exercise Physiology
CV System and Control
| Question | Answer |
|---|---|
| major functions of CV system | delivers O2, nutrients. Removes CO2, waste. Transports hormones &more. Temp and pH balance. Fluid regulation. Immune regulation |
| three components of circulation | pump, channels/tubes, fluid medium. IE: heart, vessels, blood |
| *** anatomyof heart, chamber, pericardium, pericardial cavity and fluid, valves. vessels | |
| pulmonary circulation track | deO2 blood from body to lungs: S/IVCava, RA, tricuspid, RV, pulmonary valve, pulmonary arteris, lungs |
| systemic circulation track | O2 from lungs to body: lungs, ulmonary veins, LA, mitral, LV, aoritc, aorta |
| myocardium. myocardium muscle fiber. how are fibers conneccted? how does this relate to AP conduction? | muscle of heart. only one type similar to type 1: high capillary density&mitochondria. striations. Fibers connected by intercalated disks (desmosomes& gap junctions) GJ rapidly conduct AP. |
| slide 10: compare/ontrast skeletal muscle to myocardial cells | |
| what purpose does CA2+ induced Ca 2+ release serve? | upon stim, Ca enter cell by dihydropyridine receptor in T tube and triggers ryanodine receptor to release calcium from sarcoplasmic reticulum. (Ca in T is not enough to stimulate myocardium contraction) |
| what arteries supply myocardial cells with blood? | Right coronary artery divides into marginal and posterior interventricular arteries: right side of heart . Left (main) coronary artery divides into circumflex and anterior desceding: left side of heart. |
| what is atherosclerosis. If affecting the heart, what is it called | buildup in arteries. coronary artery disease |
| intrinsic control of heart activity: how does the conduction of myocardiym have spontaneous rhythmicity? | special heart cells generate and spread (via gap junctions) electrical signal: sinoatrial node atrioventricular node, AV bundle/bundle of His, purkinje fibers. |
| average intrinsic heart rate | 100 beats/min |
| which specialized heart cell initiates contraction signal, which relay and to where? | SA initiates&RA/LA, AV delays and relays to bundle, AV bundle divides and relays to apex, purkinje send to and stimulate RV,LV |
| SA node initiates contraction signal and stimulates atria. Describe how and where the process occurs. | made of pacemaker cells in upper posterior RA wall. Signal spreads and stimulates RA/LA, which then spreads and stimulates AV node |
| AV node delays and relays signal to AV bundle. Describe how and where the process occurs. | located in RA wall near center of heart. Delay important so tetanus does not occur- heart needs to be able to fill w blood. Relays signal to AV bundle |
| AV bundle relays signal to and stimulates RV/LV. Describe how and where the process occurs. | travels along interventricular septum and divides into right and left branches and sends signal to apex of heart. |
| Purkinje fibers send signal to RV and LV. Describe how and where the process occurs. | form terminal branches of right and left bundle (from AV bund) branches. spreads throughout entire ventricle wall and stimulates RV, LV contractions |
| what nerve stimulates the heart? (extrinsic control) | Vagus (cranial X) carries implses to SA and AV nodes for parasympathetic and sympathetic activity |
| Extrinsic control of heart activity: two types | parasympathetic: rest. smpathetic: fight/flight |
| two types of control of heart activity: intrinsic, extrinsic. contrast each. | intrinsic happens by itself, extrinsic is done form brain and is regulation |
| How does the parasympathetic nervous system extrinsically control heart activity? | stimulates SA/AV nodes to release acetlcholine :. hyperpolarize cell. Results in decrease HR/force of contraction to below intrisic HR. 60-100 (35 for elite) beat/min is resting HR. |
| How does the sympathetic nervous system extrinsically control heart activity? | stimulate SA/AV node to release norepinephrine :. depolarizes. Results in increase HR/force of contraction so HR above intrinsic HR to max 250. determines HR during physical&emotional stress. Note: similar effect to endorcine system |
| what is an electrocardiogram (ECG)? What does it show? | records heart electro. activity 10 electrodes, 12 leads. Shows different electrical views. Diagnostic tool for cornary artery disease. Shows three basic phases: artiral depol, ventriculat depol, ventricular repol IE (P, GRS, T) |
| lael and ECG and cardiac cycle | |
| What are the 4 main terms decribing heart function? | cardiac cycle, stroke volume, ejection fraction, cardiac output. |
| Define cardiac cycle. | all mechanical and electrical events occurring during on heartbeat: Diastole and sytole. |
| describe ventricular systole. what is ESV? What part of ECG shows this? | contraction begins: V P rise, AV valve close, semilunar open, blood eject. Blood vol in V at end=end-systolic volume (ESV). QRS complex to T wave. 1/3 of cardiac cycle. |
| describe ventricular diastole. what is EDV? What part of ECG shows this? | Relaxation begins: V P drop. semilunar close, AV valve open, fill 70% passively & 30% by atrial contraction. blood vol in V at end=end-diastolic volume (EDV). T-QRS. 2/3 cardiac cycle |
| lub is what? dub is what? | lub is AV valves close (semilunar open). dub is semilunar valves close (AV open) |
| define stroke volume. how does it relate to EDV and ESV? | volume of blood pumped in one heartbeat. EDV-ESV= SV |
| define ejection fraction. how does it relate to EDV and ESV | % of EDV pumped. SV/EDV=EF. clinical index of contractile function |
| what is the clinical index of heart contractile function | ejection fraction AKA % of EDV pumped |
| how much blood is ejected during systole | most but not all |
| define cardiac output. how does it relate to SV (EDV, ESV). what is resting cardiac output? | total volume of vlood pumped per minute. Q=HRxSV in L/min. average resting is 5L/min |
| define functional syncytium with regards to the pumping action of heart | pumping of heart as one unit. |
| What is torsional contraction. Why is it necessary? How does this contraction occur in systole vs diastole. | increased contractility during intense exercise to enhance LV filling. During S: heat twists gradually, storing E like spring. D: abrupt untwisting allows atrial filling (dynamic relation) |
| define arteries, arterioles, capillaries, venules, veins (1,2,3,4,5) | 1: carry blood from heart 2:control blood flow and feed capillaries 3: site of nutrient/waste exchange 4: collect blood from cap 5: carry from to heart |
| what is BP, SBP, DBP, MAP | BP: P in arteries SBP/DBP. SBP: highest P in artery during systole (top number ~110-120) DBP: lowest P in artery during diastole (bottom number ~70-80 mmHg). MAP: mean arterial pressure- average P over entire cardiac cycle.~= 2/3DBP +1/3 SBP |
| what is hemodynamics | how your blood flows through your arteries and veins and the forces that affect your blood flow |
| what are two factors affecting blood flow. What provides each force? How is each force measured> | Pressure: force that drives flow. provided by heart. blood flows from HiP (LV,arteries) to LoP (veiins, RA). Pressure gradient H mmHG-Lo = Pgrad mmHg. // Resistance: opposes flow. regulated by properties of vessels. R=nL/r^4) & r is most imprtnt fctr |
| In short, Bloof Flow = Pgradient/R. what changes pressure gradient? what changes R? | Pgrad- change in P bt LV/aorta and vena cava/RA... and of course R. R-affected by vasoconstriction and vasodilation, esp in arterioles (site of most potent VC&VD responsible for 70-80% P frop from LV to RA) |
| check out figure 7.10 slide 38 | |
| where is blood distributed. Note: Q-cardiac output | to sites where most needed (of high metabolism, in heat, after eating=more flow) At rest, livers and kidneys receive 50% Q, skel mus receives 20%. During heavy exercise (Q=25L), exer muscles receive 80% via VD. flow to liver/kidney decrease via VC. |
| what is intrinsic control | ability of local tissue to constrict or dilate arterioles that serve them to alter regional flow based on need. Metabolic, endothelial, myogenic |
| how do metabolic mechanisms regulate blood flow? | in response to ^ O2, nutrient, ^pH demand. When tissues metabolize, use O2:. O2 availability decrease. VD to deliver more O2. Also in response to ^temp, K+, K+, lactic acid, inflammatory molecules buildup. |
| how do endothelial mechanisms regulate blood flow? AKA endothelium-mediated vasodilation | substances secreted by vascular endothelium IE nitric oxide (NO), prostaglandins, endothelium derived hyperpolarizing factor EDHF. For rest and exercise flow regulation. Mostly cause vasodilation. Acetylcholine+adenosine during exercise. |
| how do myogenic mechanisms regulate blood flow? AKA myogenic response | local pressure changes cause VC, VD. if high P, vc increase. If P low, increase VD. |
| what is extrinsic neural control of blood flow | redistribution at system or organ level controlled by neural mechanisms. Extrinsic bc control comes from outside specific area instead of inside tissues |
| how does neural control regulate blood flow work? | sympathetic=VC. At rest, continuous sympth impulse to maintain BP. ^sym=^VC/less flow. If need more flow, v sympth (passive ^ in flow) Vessel contraction state called "vasomotor tone". lowering normal tonic level=decrease sympth/VC |
| what is local control of muscle blood flow? | the smooth muscles of vessels do all the work in regulation for a given area (locality). |
| what is functional sympatholysis | exercise=^sympathetic=^VC. To overcome, active skel mus reduce vascular response to a-adrenergic receptor activation by release EDHF (VD :. counteracts sympathVC) |
| how much blood do veins contain at rest? | 2/3 |
| what is the venous reservoir? How can it be released to send blood to heart and into arteries? | venous system has greatest capacity to store blood bc veins are less muscle, more elastic and can fill like balloon :. provides large reservoir. how: sympathetic stimulation and venoconstriction |
| what is venoconstriction | neurogenically induced (sympathetic) contraction of the smooth muscle in the walls of veins |
| what is integrative control of blood pressure. What structures do this? | blood pressure maintained by autonomic reflexes: baoreceptors and also chemoreceptors, mechanoreceptors in muscle |
| How do baroreceptors automatically regulate BP? | sensitive to changes in arterial pressure, afferent signals to brain, efferent signals from brain to heart and vessels. Adjustment of arterial pressure back to normal |
| upright posture makes venous return to heart more difficult. What 3 mechanisms assist venous return? | one-way venous valves, muscle pump, respiratory pump |
| Define one-way venous valves (venous return) | allow blood flow in one direction/prevent backflow :. pooling in lower body. complement skel muscle pump |
| define muscle pump (venous return) | w help of valves, rhythmic mechanical compression of veins during rhythmic skel muscle contraction accompanying many types of movement and exercise. Forces blood back to heart |
| define respiratory pump (venous return) | changes in pressue in abdominal and thoracic cavities during breathing assist blood return to heart by creating pressure gradient bt veins and chest cavity |
| what are three major functions of blood. What is average blood volume in men, women? | transport (O2, nutrients, COs, waste), temp regulation, acid base balance. men: 5-6L. women: 4-5L |
| Describe the composition of blood | plasma (55-60), formed elements: RBC/erythrocytes (99%), WBC/leukocytes (<1%), platelets (<1%). |
| Define hematocrit | total percentage of volume composed of formed elements |
| describe compsition of plasma. How would its volume decrease/increase | 90% water, 7%protein, 3% nutrients,ions, etc. Decrease by 10% w dehydration in heat. Increase by 10% with training, heat acclimation |
| Describe the structure of RBC | no nucleus, contain hemoglobin |
| RBCs have no nucleus, meaning they are unable to reproduce. How are RBCs produced and destroyed? | replaced regularly by hematopoeisis. Last ~4months. produced and destroyed at equal rates |
| Hemaglobin: purpose, composition, amount per RBC, amount of O2 per 100mL blood | oxygen transporting protein (4O2/hemoglobin) 150mil hemoglob/RBC (20mL O2/100mL blood). Made o heme (pigment, iron, O2) and globin (protein) |
| define blood viscosity. Compare it to water. What increases viscosity? How does increase viscosity affect body? | thickness of blood due to RBC#. increase in vis=increase in hematocrit. 2x viscous as water. Plasma volume must increase as RBC increase to keep hematocrit/viscosity stable. otherwise blod flow or O2 transport may suffer. |
| How does plasma volume change in athletes | plasma volume increases in athletes after training and with acclimation |
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kellyyrosse
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