Term
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Definition
| Small earlike projections on each atrium |
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Term
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Definition
| Deep groove on the surface of the heart, encircling it between atria and ventricles |
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Term
| Anterior/Posterior interventriculuar sulci |
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Definition
-deep grooves that can be seen on the outer surface of the heart
-separate the right and left ventricles |
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Term
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Definition
| strong fivrous strings attached to the cusps of the tricuspid and bicuspid valves |
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Term
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Definition
-small mounds of cardiac muscle tissue projecting inward from walls of ventricles
-pull on chordae tendinae to anchor valve flaps closed when contracted |
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Term
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Definition
| large artery that gives rise to smaller pulmonary arteries that carry blood to right and left lungs |
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Term
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Definition
| period of time between the start of one heartbeat and the beginning of the next. |
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Term
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Definition
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Term
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Definition
-contraction
-heart chambers contract and push blood into adjacent chambers or into arterial trunks |
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Term
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Definition
-relaxation
-chambers relax and fill wth blood in preparation for next cycle
-when atria contract, ventricles relax
-when ventricles contrac, atria relax |
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Term
| Events of the cardiac cycle |
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Definition
1. atria relax and fill with blood (increase in fluid pressure)
2.bicuspd and tricuspid valves open and blood flows into the ventricles.
3. atria contract, ventricles completely fill with blood
4. Now there is increase in ventricle fluid pressure; ventricles contract atria relax
5.Bicuspid and tricuspid valves close; atria are fully relaxed and being to fill with blood again
6.ventricular contraction reaches it's peak; pulmonary valve and aortic valve open
7. blood leaves ventriles and goes into the arterial system, venricles relax and pulmonary and aortic valves close |
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Term
| Ventricular contraction is the ______ _____ of blood circulation |
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Definition
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Term
| ______ contraction fills the _____ with blood |
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Definition
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Term
| What is the first heart sound? |
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Definition
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Term
| What is the second heart sound? |
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Definition
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Term
| What causes the first heart sound? |
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Definition
| Occurs during ventricular systole when bicuspid and tricuspid valves close |
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Term
| what causes second heart sound? |
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Definition
| occurs during ventricular diastole when pulmonary and aortic valves close |
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Term
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Definition
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Term
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Definition
-opening through valves becomes narrower
-can occur in any 4 valves
-dizziness, shorness of breath
-produces high pitched or "click" type sound. |
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Term
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Definition
- valve does not close tightly and blood leaks back through
-can occur in any four valves
-most commonly affected valve is the bicuspid or "mitral valve prolapse"
-swishing sound |
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Term
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Definition
| stimulation to any part of cardiac muscle network sends impulses throughout entire heart muscle and it contracts as a single unit |
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Term
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Definition
| action potentials are conducted from cell to cell within the entire unit via ion passage through gap junctions linking adjacent cells |
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Term
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Definition
-atrial syncytium
-Ventricular syncytium |
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Term
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Definition
-recording of electrical changes that occur in the myocardium during a cardiac cycle
-useful in determining how the heart is or is not conducting impulses |
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Term
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Definition
| Electrical charge produced When the S-A node triggers a cardiac impulse atrial fibers deplorize |
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Term
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Definition
| a larger electrical change than P wave, lasts longer caused when ventricles deploraize |
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Term
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Definition
| wave pattern caused by ventricles repolarizing |
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Term
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Definition
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Term
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Definition
-Atria contract irregularly (P wave is gone)
-not life threatening, increased risk of stroke |
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Term
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Definition
-ventricles contract irregularly
-life threatening since vital organs lack necessary blood
-heart muscle can seize (cardiac arrest) |
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Term
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Definition
-abnormally fast heart rate
-higher than 100 beats a minute |
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Term
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Definition
-slow heart rate
-lower than 60 beats a minute |
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Term
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Definition
| -rapid rate of atrial depolarization |
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Term
| Cardiac Conduction System (CCS) |
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Definition
-cells do not contract
-Initiate and distribute electrical impulses throughout the entire myocardium
-Cells coordinate the events of the cardiac cycle |
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Term
| Components of the Cardiac Conduction System |
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Definition
-Sinoatrial Node (S-A node)
-Atrioventricular Node (A-V node)
-Atrioventricular Bundle (A-V Bundle)
-Purkinje Fibers |
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Term
Cardiac Conduction System Pathway
(6) |
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Definition
1. Cells of S-A node reach action potential threshhold on their own
2. Initiates impulses that spread into myocardium & stimulate atrial cardiac muscle fibers to contract
3. S-A impulses slow down as they reach A-V node
4. cardiac muslces move rapidly through the A-V Bundle fibers
5. Purkinje Fibers stimulate mass of ventricular myocardium to contract as a single unit
6. Organiation of the muscle fibers causes the ventricles to twist during contraction which creates pressure and pushes blood from the ventricles into the appropriate arterial trunks |
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Term
| Sinoatrial Node (S-A node) |
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Definition
-found in the right atrium
-elongated mass of muscle fibers just beneath epicardium
-fibers are continuous with the atrial syncytium
-controls heart rate |
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Term
| Atrioventricular Node (A-V Node) |
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Definition
-Found in inferior portion of interatrial septum; just beneath endocardium
-serves as a elecrical bridge between the atrial and ventricular syncytia |
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Term
| Atrioventricular Bundle (A-V bundle) |
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Definition
-found in upper portion of interventricular septum
-divides into left and right branches |
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Term
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Definition
-fored from the A-V bundle branches
-enlarged fibers that are located throughout distant regions of ventricular myocardium
-carry the cardiac impulse to all portions of ventricular syncytium |
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Term
| How does the autonomic nervous system regulate the cardiac cycle? |
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Definition
- Parasympathetic nerve fibers reach the S-A and A-V nodes
- Nerve impulse from the parasympathetic fibers causes acetylcholine to be released
- ACh decreases activity of S-A and A-V nodes, which will decrease the heart rate (act like a brake)
- Decrease in parasympathetic avtivity will cause an increase in heart rate
Symoathetic nerve fibers innervate the heart via accelerator nerves & innervate the S-A and A-V nodes
-nerve impuse from these fibers causes a release of norepinephrine
-norepinephrine increases heart rate and contraction force |
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Term
| Parasympathetic nerve fibers arise from |
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Definition
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Term
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Definition
-neurotransmitter secreted by parasympathetic fibers
-decreases S-A and A-V node activity
-decrease heart rate |
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Term
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Definition
-belong to sympathetic nerve fibers
-secrete norepinephrine
-norepinephrine increases heart rate and contraction force |
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Term
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Definition
| controls the balance between parasympathetic and spmpathetic activity on the heart |
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Term
Cardioinhibitor and cardioaccelterator reflex centers:
location:
function:
recieve signals from what receptors: |
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Definition
-within the cardiac center
-receive sensory impulses from the circulator system
-baroreceptors |
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Term
baroreceptors
function:
location: |
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Definition
-detect changes in blood pressure
-in the arch of the aorta and in the carotid arteries |
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Term
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Definition
-sense changes in pH, oxygen and carbon dioxide
-if pH level is increased heart rate is decreased
-if pH level decreased heart rate is increased |
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Term
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Definition
| They are the veins that return deoxygenated blood from the body, into the heart. |
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Term
| how is venous pressure effectively decreased? |
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Definition
-baroreceptors stretch and signal cardioaccelerator center
-cardioaccelerator center signals medulla oblongata
-medulla oblongata sends sympathetic signals to the heart which increase the heart rate and contraction force |
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Term
| how do temperature influence the rate of the cardiac cycle? |
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Definition
-body temperature increases, heart rate increases.
-if body temperature decreases heart rate decreases. |
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Term
| how do potassium ions influence the cardiac cycle? |
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Definition
Potassium ions affect the electrical potential of the cardiac muscle cell membrane which will alter the ability of the cells to reach threshhold
-Increase/decrease potassium ion concentration causes decrease in heart rate
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Term
| how do calcium ions influence the cardiac cycle? |
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Definition
-Cacium ions affect the conductance of cardiac impulses
-increased calcium levels cause an increase in heart rate |
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Term
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Definition
| increased calcium ion levels |
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Term
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Definition
| form a closed circuit of tubes that carry blood from the heart to body cells and back to the heart |
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Term
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Definition
| Carry blood away from ventricles of heart and lead into capillaries |
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Term
| 3 layers of arterial/arteriole wall |
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Definition
Tunica Interna: innermost; made of endothelium
Tunica Media: forms bulk of wall (middle layer); made of smooth muscle and elastic connective tissue
Tunica Externa: outermost layer; attatches artery/arteriole to surrounding tissues |
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Term
vasomotor fibers
function: |
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Definition
-Sympathetic nervous system fibers
-innervate the smooth muscle of the tunica media
-when stimulated cause vasoconstriction
-when inhibited, cause vasodilation |
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Term
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Definition
-smallest diameter blood
-Carry out the exchange of substances between the blood and tissue cells |
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Term
precapillary sphincters
function: |
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Definition
-muscle that encircles the true capillary entrances
-regulates distribution of blood through capillaries |
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Term
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Definition
| exchange of substances through capillaries by water moving from areas of high concentration to areas of low concentration |
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Term
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Definition
exchange of substances through capillaries by movement of solutes from areas of high concentration to areas of low concentration
-most important |
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Term
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Definition
exchange of substances through capillaries by movement of large olecules like sugars and salts carried out by active forces pushing fluid across capillary wall.
Osmotic pressure: pulls fluid into capilarries
Blood pressure: tends to push fluids out of capillaries |
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Term
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Definition
| arterial end of capillar higher hydrostatic pressure so fluid moves out |
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Term
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Definition
| venous end of capillary has higher osmotic pressure so fluid moves in |
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Term
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Definition
| Carry blood back to Atria of the heart |
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Term
| _____ are smaller diameter vessels which connect to the ________ end of capillaries and then merge to form _________ |
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Definition
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Term
|
Definition
Tunica externa: outermost composed of thick connective tissue
Tunica Media: Middle layer
Tunica interna: innermost layer; composed of endothelial tissue |
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Term
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Definition
| helps return more blood to the heart; which helps maintain blood pressure |
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Term
| larger veins have valves that originate from the ______ ______; project inward and prevent ______ of blood |
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Definition
| tunica interna; back-flow |
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Term
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Definition
| force that exerts against the inner awlls of blood vessels |
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Term
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Definition
maximum arterial pressure due to ventricles contracting; blood is forced into pulmonary trunk and aorta.
-sharp rise in blood pressure |
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Term
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Definition
| minimum arterial pressure and is caused by venricular relaxation |
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Term
| Factors influencing Blood Pressure |
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Definition
-Heart action
-blood volume
-peripheral resistance
-viscosity |
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Term
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Definition
| how much blood enters the arterial system with each ventricular contraction will influence BP |
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Term
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Definition
| volume of blood discharged from the ventricles with each contraction |
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Term
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Definition
| volume of blood discharged/minute |
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Term
| if the heart rate or stroke volume ______________ the CO ________________ this causes an increase in ________ |
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Definition
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Term
| If the heart rate or stroke volume ___, the CO _____. This causes a decrease in _____. |
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Definition
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Term
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Definition
Sum of formed elements (cells and platelets) and plasma volume.
-BP is directly proportional to blood volume
- if blood volume +, BP +
-if blood volume -, Bp- |
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Term
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Definition
force produced by friction between blood and walls of blood vessels.
-hinders blood flow |
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Term
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Definition
| increase peripheral resistance and increases BP |
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Term
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Definition
| decreases peripheral resistance and decreases BP |
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Term
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Definition
how thick something is; how easily a fluid's molecules flow past one another
+ in viscosity, + in BP
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Term
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Definition
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Term
Vasomotor Center
location: |
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Definition
-located in medulla oblongata
-controls blood vessel diameter |
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Term
Nervous system regulation
4 things |
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Definition
-Vasomotor center
-Baroreceptors
-chemoreceptors
-higher brain centers |
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Term
| Baroreceptors (bp control) |
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Definition
Elevated BP causess baroreceptor stimulation
casodilation occurs |
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Term
| chemoreceptors (bp control) |
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Definition
increase in co2 levels or o2 levels will stimlate chemoreceptors
sympathetic fibers stimlated
vasoconstriction occurs |
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Term
| cerebral cortex (Bp control) |
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Definition
| in times of high stress or anxiety will send signals that cause an increase in Bp |
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Term
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Definition
| mediatesfight or flight response |
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Term
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Definition
| controlling how much aldosterone is secreted by adrenal cortex |
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