heart, topic 2 Flashcards
what is pulmonary circulation?
from the heart to the lungs and back
-picks up O2 and dumps CO2
what is systematic circulation?
from the heart to the whole body and back
-picks up CO2 and dumps O2
what is coronary circulation?
circulation of blood through heart tissue
what are the coronary arteries?
suppku O2 and nutrients to heart tissue
What is the diastole
part of the heart cycle where the heart is relaxed
-atria and ventricles passively fill
-AV valves (tri and bicuspid) allow blood to pass
Why are aortic and pulmonary valves closed in the diastole stage?
because the blood in those vessels are at a higher pressure than the ventricles.
what is the systole?
part of the heart cycle where the heart contracts and push blood through its chambers
What do the atria do in the systole stage?
contract and eject blood from the heart into the ventricles
What happens to the AV valves and ventricles in the systole stage?
AV valves close, preventing back flow with ventricles contract.
-ventricles eject blood out the lungs and rest of the body
What is the hearts beat rate set by?
sinoatrial node (SA node)
-specialized bundle of nerves which acts as a pacemaker for heart
How does the pacemaker increase or decrease?
through signals from the nervous system which increase or decrease heart rate
what is the sinoatria (SA) node?
located in the right atrium
-generates an electrical signal that spreads over the two atria and makes them contract simultaneously.
What is the atrioventricular node?
Receives signal from SA and node transmits signal to the purkinje fibers
What do purkinje fibers do?
Begin the contraction of the ventricles
What does EKG stand for?
Electrocardiogram
What are the heart sounds produced by?
Closing valves “lub dub”
Where is the lub sound from?
Tri and bicuspid valves closing during contraction (systole) of AV valves
Where does the dub sound come from?
Aortic and pulmonary valves closing during relaxation (diastole)
In what unit is heart rate measured?
Beats per minute
What are ways heart rate changes?
-exercise (muscles demand O2 and food generating more waste)
-stress or excitement (body perceives need for fight or flight)
-chemicals (nicotine, caffeine directly stimulates the nerves that control the heart)
What is blood pressure?
Force your blood exerts on your blood vessels
What are the two levels of blood pressure?
- Systole (pressure during ventricular contraction)
- Diastole (pressure as the heart refills)
What is the average brachial artery pressure?
120 systolic over 80 diastolic
How is pressure in the arteries and veins?
Highest in arteries and very low in veins
What unit is blood pressure measured in?
mm of mercury (Hg)
How is blood pressure measured?
Using a stethoscope and sphygmomanometer
What is blood pressure regulated by?
Baroreceptors (pressure sensors)
Where/what is high blood pressure?
Detected In the aorta
-tells the brain to dilate (widen) blood vessels
Where/what is low blood pressure?
Detected in the carotid arteries
- tells brain to constrict (narrow) blood vessels
