Exam 2-Cardiovascular System Flashcards
What is cardiac output?
Volume of blood pumped by the heart in one minute.
Cardiac output can be found by multiplying heart rate by the stroke volume; an increase in stroke volume or an increase in heart rate will increase the cardiac output and vice versa.
The rate at which blood is returned to the atria from the vein in one minute is considered ________ return?
Venous
This rate can limit cardiac output.
What is stroke volume?
The volume of blood pumped out of each ventricle with each contraction
The period of cardiac contraction and emptying is the _______ period?
Systolic
Systolic pressure is the measure of what?
The pressure in the artery after blood has been ejected from the left ventricle; this is the highest arterial pressure measurement during the whole cardiac cycle.
What is the period called when the heart relaxes and feel back up with blood?
Diastolic
_______ pressure measures the pressure on the artery when no blood is being ejected from the left ventricle; when the lowest arterial pressure is being measured during the cardiac cycle.
Diastolic
What is pulse pressure?
The difference between the systolic and diastolic pressure
The end _______ volume is the volume in the ventricle before ejection; when the heart is ready to contract.
Diastolic (preload volume)
What is the end systolic volume measuring?
The volume in the ventricle after ejection
What is the equation for the MAP or mean arterial pressure? What is this measuring?
Diastolic pressure+ 1/3( Systolic pressure-Diastolic pressure); The average pressure responsible for driving blood forward into the tissues throughout the cardiac cycle.
What are the three characteristics of blood?
- Viscosity: thicker than water because RBCs
- Temperature: higher than than body temp.
- Slightly alkaline: contains less CO2
The three functions of blood in the body are ______, _______ and __________.
Protection, transportation, and regulation
What must be present in order for the liver to synthesize the clotting factors II, VII, IX, X?
Vitamin K
What is happening to the ventricles during the ST segment?
They are depolarizing, contracting and emptying
What phase of the action potention propagation does the ST segment correspond with?
Phase two: The plateau phase of the action potential in ventricular muscle cells
During the PR segment what is happening to the AV node?
The AV node is delayed in its induction
Why is the AV node’s conduction delayed?
In order to let the atria empty the blood into the ventricle before the ventricle contracts
What part on an ECG represents the area form the end of the P wave to the begining of the QRS complex?
The PR segment
What is the period on the ECG called that begins at the end of the S wave and ends in the begining of the T wave?
The ST segment
How do you calculate the HR using a rhythm strip?
Count the # of QRS complexes between the 3 second markers and multiply by 20
or
Count the # of QRS complexes between the first and third markers (6 seconds) and multiply that number by 10 (more accurate)
True or False: An erythrocyte has an endoplasmic reticulum and a nucleus
False; an erythrocyte is a fully mature red blood cell which loses those structures
What type of cell derives from hemocytoblast and commits to becoming a red blood cell?
Myeloid stem cell
What are erythroblasts called that lose their nucleus?
Reticulocytes
If the length occupied by plasma is 42mm and the length occupied by red blood cells is 38mm, what is the hematocrit value?
42 + 38 = 80
38/80 = 48%
What is the process call when red blood cells are created and are mature?
Erythropoesis
In red blood cells, what carries oxygen?
Iron in the heme group in hemoglobin
What does CO2 bind to in RBCs and what is the name of its form?
It binds to globin
and the form is called carbaminohemoglobin
If O2 carrying capacity decreases, what will the kidney do to increase the O2 carrying capacity?
It secretes erythropoietin
What is the production of platelets called?
Thrombocytopoiesis
Why are megakaryocytes important in platelet production?
They shed their cytoplasm which becomes platelets
What hormone stimulates production of megakaryocytes?
Thrombopoietin
Where are most platelets stored and how long can they stay in the blood before they’re destroyed?
The spleen
10 days;
macrophages eat them; they are released from the spleen due to the sympathetic induced splenic contraction
Name the 3 functions of platelets:
- Transport clotting chemicals
- Form a platelet plug
- Contract to shrink clots
True or False: Platelets contain actin and myosin.
True; this enables the clot to contract bringing the walls of the vessels together to seal the injury.
What agents released from platelets vasoconstrict blood vessels?
Serotonin
Thromboxane A2
When platelets come into contact with collagen,what agent causes them to become sticky?
What agent enhances the above agent?
ADP
Thromboxane A2
What does the Von Willebrand factor do?
Where is it synthesized from?
It anchors the clot to the epithelium and prevents it from washing away
It is synthesized by endothelial cells
Ca2+ released from platelets is required from _________ and __________
Platelet aggregation and clotting
What agent stimulates the division of endothelial cells, smooth muscle cells, and fibroblasts?
Plate derived growth factor (PDGF)
What is the end stage of the vacular spasm step in hemostasis?
Endothelial cells become sticky and release von willebrand factor
When a platelet plug has been formed, prostacyclin inhibits further platelet aggregation is this is considere dthe last step in the ____________ phase of hemostatsis.
Platlet plug formation
If factor XII is activated when platelets come into contact with collagen, what clotting pathway is this considered part of?
Intrinsic
True or False: The extrinsic pathway is slow acting and si activated when the outside of blood vessels rupture.
False: The extrinsic pathway is fast-acting
Which clotting pathway involves activated platelets releasing thromboplastin (TF)?
Extrinsic
Which two vitamins are essential for clotting?
Calcium (Ions)
Vitamin K
Which clotting factor binds with Ca2+ ions and forms prothrombinase?
Factor V, which previously combined with activated Factor X
Which clotting pathway is shared at the end of the intrinsic and extrinsic pathways?
The Common Pathway
How is thrombin formed during the common pathway of coagulation?
When Ca2+ bins to thrombin, what occurs?
Prothrombinase and Ca2+ catalyze prothrombin into thrombin
Fibrinogen is converted to fibrin which strenghtens the blood clot
To ensure the clot doesn’t grow out of control, has to happen?
Fibrin can inactivate thrombin distrupting the positive feedback loop
What is heparin and what does it do?
Anticoagulant; can be natural or a drug
Stimulates the activation of antithrombin III which inhibits thrombin ( a procoagulant)
Which anticoagulant inhibits platelet aggregation and opposes stimulation of ADP?
Prostacyclin
If certain clotting factors can not be synthesized due to the blocking of Vitamin K, what is the most probable explanation?
The anticoagulant drug, warfarin, was administred to the patient, blocking Vitamin K
If fibrin in the clot starts dissapearing, which anticoagulants could be at work?
tPA
Streptokinase
Converts plasminogen to plasmin which digtest fibrin
Thrombin can be inactivated by _______, a proagulant.
Antithrombin III
Which drug do you have to be very careful about administering because it directly degrades fibrin into fibrinogen?
Urokinase
How to EDTA tubes prevent coagulation of a blood sample?
The coating on the sides of the test tube removes Ca2+ from the plasma
How does thrombin assist in fibrinolysis?
It indirectly inhibits an inhibiator of tPA allowing tPA to be released which converts plasminogen to plasmin
Plasmin digest fibrin
What does MAP stand for and how is it calculated?
Mean Arerial Pressure: average pressure responsible for driving blood foward into tissues
Diastolic pressure + 1/3 (Systolic pressure - Diastolic Pressure)
What does Isovolumetric mean?
The volume does not change, it stays the same throughout the cycle
When does isovolumetric contraction occur?
Early in ventricular systole when all the valves are closed and the ventricles are beginning to contract; the volume of blood in these moments does not change due to all valves still being closed (AV and Semilunar).
Ventricular contraction completes, the semilunar valves close due to backflow of blood from the aorta and pulmonary trunk. The AV valves are still closed as the ventricles relax keeping the volume of blood in the ventricles the same. What is this phenomenum called?
Isovolumetric Relaxation
