A & P: Test 3 (5) Cardiac Output/BV and Physiology of Circulation
- Texas State University-San Marcos
- Biology 2452
- A & P: Test 3 (5) Cardiac Output/BV and Physiology of Circulation
Last Modified: 2011-07-04
- volume of blood pumped out by one ventricle in one minute
- changes according to needs of the body
- difference between the basic CO at rest and the max XO while exercising
- an indication of how good your cardiovascular system is
- well-trained athlete: high CR---35L/min, 7 times basic CO)
- non-athlete: CR--20-25L/min (4 to 5 times the basic CO)
- SV = EDV-ESV
- EDV- end diastolic volume (120 ml of bld)
- ESV- end systolic volume (50 ml of bld)
- after load
- refers to the pressure exerted by blood on the wall of ventricle at the end of vent diastole
- Increase in EDV will increase the degree of stretch, and thereby increase the force of contraction.
- EDV will increase when venous return increases as during exercise
- increase in the force of contraction also increase SV.
- Norepinephrine (NE)- inc force
- Cal ions, glucagon, and thyroxine also increase
- positive: all factors that increase the contractility
- negative: slow down or inhibit heart's contractility (excess hydrogen ions in bld that inc acidity, inc levels of potassium ions)
- refers to back-pressure by aortic blood (80 mm of HG), and blood in pulmonary blood (8 mm of HG) on SLVs.
- When back pressure increases as during HB pressure (hypertension), ESV increases and SV decreases
- Sinus rhythm- at rest, initiated/coordinated by the SA node, but altered by
- when body is under stress, this is activated.
- by means of sympathetic fibers and NE stimulate the heart and increases the HR
- at rest, this, by means of vagus nerve (parasympathetic) and ACh inhibits HR.
- detects blood pressure changes,and help regulate BP by changing HR
- receptors in the wall of aorta and carotid sinus send impulses to CIC when the arterial blood pressure increases
- CIC reduces HR, and tends to bring down the bp temporarily
- located in wall of atria detect increase in venous bp when venous return to heart increases as during exercise.
- these then send impulses to CAC to increase HR in order to clear off the increased venous and prevent heart congestion
- baroreceptors impulses to CAC to inc HR--prevent congestion
- epinephrine, norepinephrine and thyroxine increase HR
- decreased bld cal levels (hypocalcemia) reduces HR
- increased bld cal levels (hypercalcemia) increases HR to such an extent, heart beast with very little rest, pump very little blood (spastic)
- low sodium does not affect HR, but High sodium in bld (Hypernatremia) adversely affect heart functions
- when sodium content in bld increases, heart releases this hormone
- which inhibits aldosterone and decreases sodium absorption and retention by the kidneys
- low potassium level in blood (hypohalemia) weakens the heart and causes irregular heart beat (arrhythmia)
- high potassium content (hyperkalemia) slows down the depolarization of cardiac fibers, leads to heart block and cardiac arrest, death.
- age affects HR
- Infants- high (140-160/min)
- HR declines w/ age
- in females is higher (72-80/min)
- males (64-72/min)
- cold decreased HR
- head increases HR
- around 90 mm Hg
- becomes 20m Hg by the time blood reaches capillaries
- BP in veins 15 mm Hg
- in vena cava close to 0
- brought about by vasoconstriction and vasodilation, controlled by the vasomotor center in medulla oblongata
- vasoconstriction increases peripheral resistance and increases systemic bp
- regulated by the kidneys which control the amount of fluid retained by the body
- take blood away from heart
- thick smooth muscle layer, w/ plenty of elastic tissue
- blood under systolic pressure
- BP declines as the blood reaches bld capillaries
- except pulm. trunk, arteries carry oxygenated blood
- muscular arteries
- smaller arteries with very little elastic tissue
- elastic arteries
- act as "elastic tubes"
- aorta and its branches close to heart
- very small arteries w/ a relatively thin layer of smooth muscles
- branch out to form blood capillaries
- take blood towards the heart
- thick outer conn tissue layer, thin smooth muscle layer
- blood flow directed by pocket valves
- except for pulm veins, veins carry deoxygenated
- veins are formed by these
- small veins
- formed by blood capillaries
- exchange area in blood circulation
- microscopic blood vessels with one-cel thick walls (made of one layer of endothelium)
- is equal to diastolic pressure + 1/3 of pulse pressure
- keeps the blood flowing through the arteries
- clogging of the coronary arteries reduces oxygen supple to myocardium and causes Hypoxia
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