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HHP Ch14
Cardiac Output and Blood Flow
| Question | Answer |
|---|---|
| Describe the factors of cardiac output | volume of blood ejected per beat per minute Stroke Volume and Heart Rate |
| Explain the Frank-Starling law of the heart. | SV vs EDV . The law states that the stroke volume of the heart increases in response to an increase in the volume of blood in the ventricles, before contraction (the end diastolic volume), when all other factors remain constant. |
| ID the forces that act in capillaries | starling forces: Blood Hydrostatic Pressure Interstitial hydrostatic Pressure Blood Osmotic (Oncotic or colloid) Pressure Interstitial Osmotic pressure |
| Describe the maintenance of blood volume by Antidiuretic Hormone (ADH) | secreted by pituitary gland in response to low blood volume and/or increase blood osmolarity. Increases water retention by kidneys (less urine) |
| Explain the mechanisms that regulate blood flow to the various tissues | -blood viscosity -vessel length -vessel radius* |
| Explain the importance of Mean Arterial Pressure (MAP) | measures the pressure necessary for adequate perfusion of the organs of the body *perfusion: process in which blood is forced to flow through a network |
| Be able to calculate Mean Arterial Pressure | DBP+1/3 (SBP-DBP) cardiac output*total peripheral resistance |
| Describe dangers of hypertension | "silent killer" : causes other issues that kill -congestive heart failure (blood in lungs bc heart backup) -stroke (brain vessel burst) -heart attack -spontaneous hemorrhage -renal failure (^P) -retinal damage (^P) |
| Describe the potential causes primary hypertension. | -defects in salt management by kidneys -excessive salt intake -diets low in K and Ca -excess vasopressin |
| factors of stroke volume | -^ w ^End Diastolic Volume (^preload<- ^venous return) -v w ^Total Peripheral Resistance (afterload) -Sympathetic activity (contractility and venous return) |
| factors of heartrate | alternating balance of parasympathetic and sympathetic influence on SA node. Symp: less hyperpolarization :. less depolarization to beat :. faster HR Para- greater hyperpolarization :. greater depolarization to beat :. slower HR |
| factors influencing venous return. which influence SV | -P difference bt arteries and veins -sympathetic stimulating smooth muscle contraction and lower -compliance (stiffness) -blood volume -skele muscle pumps -body positioning |
| factors influencing blood volume, which influence SV | -v urine volume -tissue fluid volume (osmotic forces move fluid between interstitial spaces and blood) |
| factors influencing EDV (end diastolic volume), which influences SV | -v afterload Ventricle pressure > aortic valve (total periph resistance) P. however KIM that EDV peaks because more blood ejected (then rest) means more afterload |
| Ejection Fraction | fraction of blood pumped out w each heart beat SV/EDV * 100 normal fraction 50-55% |
| Define Hydrostatic Pressure, a force that acts in capillaries | pressure of fluid within capillary or on capillary wall Blood HP: P of blood on wall Interstitial HP: P of IF on wall |
| Define Osmotic/Oncotic/Colloid Pressure, a force that acts in capillaries | osmotic pressure of proteins within or outside of capillary Blood O/CP: proteins in blood/in capillary I O/CP: proteins outside of blood/capillary |
| What do Starling Forces predict? | Net Filtration: movement of fluid out of capillaries at the arteriole end (+) Net Absorption: movement of fluid into capillaries at venule end (10-15% remains in interstitial spaces and will enter lymphatic capillaries and return to venous system) |
| Describe the maintenance of blood volume by aldosterone | secreted by adrenal cortex in response to low BP and low blood flow to kidneys. Increases reabsorption of Na+ (^salt-water retention in kidneys). |
| Describe the maintenance of blood volume by Atrial Natriuretic Peptide (ANP) | produced by atria when heart stretched. Inhibits ADH secretion and antagonist of aldosterone. Promotes salt and water excretion in urine in response to increased blood volume |
| What regulates aldosterone? | Regulated by Renin-angiotensin aldosterone system (RAAS). Found in pulmonary circulatory system |
| Blood Flow Equation | P- force exerted by blood (Arterial-Venous) F- blood flow rate thru vessel R- resistance of blood vessels/flow (R proportional to 1/r^4) F=P/R |
| Define Blood Pressure and give factors of BP | force exerted by blood against vessel wall -blood V in vessel -compliance (stretchability) of vessel walls |
| Define Systolic Pressure | maximal arterial pressure average 120 mmHg |
| Define Diastolic Pressure | minimum pressure in arteries when blood is draining off into vessel downstream average 80 mmHg |
| Define Pulse Pressure | difference between systolic and diastolic pressure (SP-DP) using average: 120-80= 40 mmHg |
| Define Men Arterial Pressure. What are primary determinants of MAP? | Average pressure driving blood forward to tissues throughout cardiac cycle AKA BP that is monitored and regulated in body Cardiac output Total peripheral resistance |
| Define Total Peripheral Resistance (TPR) | sum of all vascular resistance in SYSTEMIC circulation |
| Factors influencing TPR | Extrinsic -Sympathetic -Epinephrine -Hormones (Angiotensin II and Vasopressin) Intrinsic -Autoregulation promotes constant blood flow (ex active hyperemia) -arterioles (major resistance vessels :. det. MAP) -smooth muscle constriction/dilation |
| Define active hyperemia and explain the process | Overrides sympathetic response to exercise stressor CV system work harder so blood moves to organs: ^organ activity-> v O2/^metabolites in interstitial fluid by organ->arteriolar dilation in organ-> ^blood flow to organ |
| Short term maintenance of MAP/BP | Baroreceptors (carotid sinuses, aortic arch) sense BP change and fire proportionally, signaling medulla oblongata to ^ v sym/para activity, affecting arteriole diameter and HR, :. affecting TPR (art.) and cardiac output (HR) :. maintain BP |
| Long term maintenance of MAP/BP | adjust normal salt:water balance thru mechanisms that regulate urine output. Takes minutes to days |
| Define hypertension (include #s), include primary and secondary hypertension | BP > 140/90 primary- no real cause secondary- caused by disease or condition |
| Define hypotension (include BP #s) | BP < 100/60 no issue unless have symptoms occurs when too little blood to fill vessels or heart too weak to drive blood |
| Define circulatory shock | occurs when BP falls so low that adequate blood flow to tissues can no longer be maintained, causing tissues to die |
| Define congestive heart failure | "congestive"=^ in fluid retention cardiac output is not sufficient to maintain blood flow required by the body often secondary to myocardial infraction (heart attack) |
| What is orthostatic/postural hypotension | stand to sit/sit to stand to fast and feint due to too slow of blood flow to head |
| Acute Effects on CV system | ^ Cardiac output: ^HR w ^sym/ v para SV ^ bc ^HR :. ^ push :. ^blood until max HR reached bc then not enough time in bt beats for heart to fill :. pump :. vSV |
| Training/Long term Effects on CV system | ^ cardiac output: ^SV bc heart is stronger & more stretchable :. better at filling and pumping HR does not change w fitness |
Created by:
kellyyrosse
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