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Cardiovascular vocabulary and Study questions
Terms in this set (74)
The electrical activity occurring in the heart
What does an ECG measure?
When the atria depolarize
What does a P wave correlate to?
When the ventricles depolarize
What does the QRS wave correlate to?
When the ventricles repolarize
What does a T wave correlate to?
EDV (end diastolic volume)
The amount of blood in the ventricles before contraction
ESV (end systolic volume)
The amount of blood left in the ventricles after contraction
Stroke volume x heart rate
Cardiac output equals?
EDV - ESV
Stroke volume equals?
The contraction phase of the cardiac cycle
The relaxation phase of the cardiac cycle
The AV valves being forced shut by ventricular contractions
What is the "lub" sound of the heartbeat?
The semilunar valves being forced shut by blood pressure from the arteries falling on them during ventricular relaxation
What is the "dub" sound of the heartbeat?
The sound of the heartbeat made when the AV valves are forced shut due to contraction of the ventricles
The sound of the heart beat made when the semilunar valves are forced shut due to blood pressure falling back on them from the large arteries when the ventricles release their pressure.
Comes in through vena cava to right atrium
How does deoxygenated blood first enter heart?
Goes through AV valve to right ventricle
Where does deoxygenated blood go after it comes in through vena cava and is in the right atrium?
Goes through pulmonary semilunar valve to pulmonary trunk and arteries to lungs
Where does deoxygenated blood go after it goes into the right ventricle?
Comes in through pulmonary veins to left atrium
How does oxygenated blood from lungs re-enter heart?
Goes through mitral malve to left ventricle
Where does oxygenated blood go after it comes in through pulmonary veins and is in the left atrium?
Goes out through aortic semilunar valve to aorta to body
Where does oxygenated blood go after it goes into the left ventricle?
Consistes of short branching fibers that connect to one another via intercalated discs
What is the structure of a cardiac muscle fiber?
Gap junctions that allow the movement of ions from one fiber to the next
What are intercalated discs?
This allows for action potentials started in one area of the cardiac muscle to be spread to other areas
What are intercalated discs for?
Leaky sodium channels that are always open slowly depolarize to threshold
How do conducting cells depolarize?
because cells can depolarize on their own and start an action potential one it reaches threshold
How does the leaky sodium channels on conducting cells lead to their ability to be autorhythmic?
Starts at the SA node
Where does an action potential first begin conducting?
Moves through atrial tissue to AV node in lower right atrium
Where does an action potential go after it starts at the SA node?
Moves down to the AV bundle which is within the interventricular septum
Where does an action potential go from the AV node?
Moves down the septum's bundle branches
Where does an action potential go from the AV bundle or Bundle of His?
Moves through the Purkinje fibers up the outer sides of ventricles
Where does an action potential go from the bundle branches within the interventricular septum?
The heart is relaxed and blood is passively filling the ventricles by passing through the atria and open AV valves.
(1) What happens during late diastole?
The AV valves begin to close and the atria start to fill with blood
(2) What happens towards the end of diastole as the ventricles fill up?
The atria are depolarized by the SA node
(3) What happens at the beginning of systole, when atria are full?
The atria contract forcing a small amount of blood past AV vales and into ventricles
(4) What happens when the atria contract?
The atria relax and action potential moves to the ventricles
(5) What happens after the atria contract?
The ventricles contract, shutting AV valves and opening semilunar valves, forcing blood out the aorta ad pulmonary trunk
(6) What happens when the action potential reaches the ventricles?
The ventricles relax and the semilunar valves close and AV valves open, allowing blood to passively fill the ventricles again
(7) What happens after the ventricles contract?
Increased EDV with increased venous return
What happens to the end-diastolic volume (EDV) in relation to venous return?
Decreased ESV with more forceful contractions stimulated by either regular exercise or the sympathetic nervous system
What happens to the end-systolic volume (ESV) in relation to more forceful contractions
They both contribute to the stroke volume; increased EDV or decreased ESV increase stroke volume; this in turn contributes to cardiac output
How can EDV and ESV be used to determine cardiac output?
Their flaps hang down into the ventricles and the valves are open
How do the bicuspid and tricuspid valves function when they are relaxed?
The pressure of the blood below them in the ventricles pushes flaps upward closing the valve
How do the bicuspid and tricuspid valves function as ventricles fill with blood?
The forceful contraction and pressure forces them shut to prevent backflow
How do the bicuspid and tricuspid valves function as ventricles contract?
The pressure of blood from the arteries holds the flaps closed
How do the semilunar valves stay closed?
When ventricular ressure rises above that of the arteries, it forces the valves open
How do the semilunar valves open?
Their flaps open up into the aorta and pulmonary trunk
What is the anatomical state of the semilunar vaves
Stroke volume and heart rate
What two factors influence cardiac output?
Increased blood pressure will increase the ESV since less blood is able to get out of the ventricles against the high pressure in the arteries; this decreases stroke volume and cardiac output
How does blood pressure relate to cardiac output?
Increased muscle size will decrease ESV since ventricles can contract with greater forceand move more blood out of the ventricles; This increases cardiac output
How does heart muscle size relate to cardiac output?
The inability of the heart to generate enough cardiac output to effectively supply blood to the tissues
What is congestive heart failure?
It leads to a reduced flow of blood to the heart muscle, potentially leading to a heart attack which kills cardiac muscle tissue making the heart weaker and bringing it closer to CHF.
How does coronary ateriosclerosis contribute to congestive heart failure (CHF)?
It makes it difficult for the ventricles to force blood into the arteries so cardiac output is low. Over time, this causes the heart to hypertrophy, which eventually leads to damaged heart tissue, a weaker heart, and CHF
How does high blood pressure contribute to congestive heart failure (CHF)?
By the pressure generated by the heart
How does blood get moved through the ateries?
Elastic arteries stretch when blood enters them relieving some of the pressure and recoil back when the heart isn't contracting to give aother push of blood through the vessels. This helps maintain pressure while the heart is't working.
How do the elastic arteries work to maintain relatively constant blood flow?
By using the sympathetic nervous system and peripheral tissues
How can the body change the distribution of blood flow?
An increase in sympathetic activity will constrict vesseles going to digestive and urinary organs and dilate vessels going to skeletal muscle
How can the body use the sympathetic nervous system to change the distribution of blood flow?
If a tissue is active it will be relatively low in oxygen and carbon dioxide leading to dilation of vesels entering the organ so that more blood can fuel the active tissue
How can the body use the peripheral tissues to change the distribution of blood flow? If a tissue is active....
If a tissue is inactive, it will be relatively high in oxygen and low in carbon dioxide leading to constriction of vessels so that blood can be used elsewhere
How can the body use the peripheral tissues to change the distribution of blood flow? If a tissue is inactive....
Hydrostatic pressure and diffusion
By what two mechanisms do substances move out of the capillaries and into the tissues?
By diffusion depending on the direction of its chemical gradient
How do dissolved substances move back into the capillaries?
Hydrostatic pressure causes everything small enough to move out of the capillary in the same concentration as it was found in the capillary
By osmotic pressure created by proteins found in the capillary
How does water move back into the capillaries?
Towards the end of the capillary bed because hydrostatic pressure is low
Where does water move back into the capillaries and why?
It would increase the hydrostatic pressure therefore increasing blood flow out of the capillaries. This can cause edema and possibly the bursting of capillaries
How would an incease in blood pressure affect capillary filtration and the tissues surrounding the capillaries?
Muscular pumps and respiratory pumps
By what two mechanism does blood move through the
In the arms and legs where large vessels are run between muscle groups
Where are muscular pumps located?
As muscles contract and squeeze blood is moved up toward the torso; As muscles relax pressure is released and vessels can refill; valves preventr backflow
How do muscular pumps work?
In the abdominal cavity
Where are respiratory pumps located?
During inhalation the diaphragm pushes down on the abdominal cavity increasing the pressure in the abdominal cavity and vena cava; This forces blood into the thoracic cavity; During exhalation, pressure is released, alowing blood to refill the vena cava
How do respiratory pumps work?
Increase in venous return increase the amount of blood in the ventricles before contraction (EDV); Stroke volume can be higher because there is more blood to work with increasing cardiac output
How does venous return affect cardiac output?
peripheral resistance and cardiac output
What factors affect blood pressure?
Increased cardiac output increases blood pressure; decreased cardiac output deceases blood pressure
How does cardiac output relate to blood pressure?
Decreased peripheral resistance (dilated vessels) decreases blood pressure; Increased peripheral resistance (constricted vessels) increases blood pressure
How does peripheral resistance relate to blood pressure?
The higher the blood pressure, the faster the flow rate of blood through the arteries and the system as a whole; Maintain balance of right amount of flow for whatever activity
Why is cardiac output and peripheral resistance inportant to maintaining blood pressure?
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