Cardiovascular 2 Flashcards
How much blood does the heart produce in one day?
About 6000 quarts
How many times does blood go through the heart in one day?
1000 times
How often do the atrial cells beat?
60 times per minute
How often do the ventricular cells beat?
About 20-40 times per minute
What does the heart need so that it is an efficient pump?
A unified control system
What is the nodal system also called?
The intrinsic conduction system
What is the SA node also called?
Sinoatrial node
What is the SA node?
The most important part of the intrinsic conduction system
What does the SA node look like and where is it located?
crescent shaped node
of tissue, located in the right
atrium
What is the AV node also called?
The atrioventricular node
Where is the AV node located?
at the junction of the
atria and ventricles
What is the bundle of His also called?
Atrioventricular (AV)
bundle
Where is the bundle of His located?
the right and left bundle
branches located in the
interventricular septum
Where are the purkinje fibers?
spread within the
muscle of the ventricle
walls.
What does operation of the AV valves do?
This system causes heart
muscle depolarization in only
one direction, from the atria to the
ventricles.
How often does the operation of the AV valves cause the heart to contract?
75 beats per minute
What allows for the heart to beat as a coordinated unit?
The operation of the AV valves
What does ECG stand for?
Electrocardiography
What is an ECG?
The clinical procedure
for mapping the
electrical activity of the
heart
What contraction
effectively ejects blood
superiorly into the large
arteries leaving the heart?
The function of the AV valves, specifically the ventricles contracting
What do the atria do in a healthy heart?
They contract simultaneously
When do the ventricles contract?
As the atria start to relax
What does systole represent?
Contraction
What does diastole represent?
Diastole
What does the cardiac cycle refer to?
the events of
one complete heartbeat, both atria and ventricles
contract and then relax
What is the average length of this cycle?
.8 seconds
What are the three periods during the cardiac cycle?
- Mid–to–late diastole
- Ventricular systole
- Early diastole
What happens during ventricular systole? (3 things)
Ventricular contraction
(systole) begins.
* Pressure within the
ventricles increases
rapidly.
* AV valves close creating
the first heart sound
“lub”.
What happens during early diastole? (2 things)
Systole ends,
ventricles relax.
* Semilunar valves
snap shut and
create the second
heart sound “dub”.
What is cardiac output (CO)?
the amount of blood
pumped out by each
side of the heart
(actually each ventricle)
in one minute.
How do you find cardiac output?
Heart rate times stroke volume
What is normal resting heart rate?
75 bpm
What is normal stroke volume?
70 ml per beat
What is normal cardiac output?
5250 ml/min
What do the blood vessels do?
The blood circulates through them
What do the blood vessels form?
A vascular system
What kind of transport system is the vascular system?
Closed
How does the blood travel through the blood vessels?
As the heart beats, blood
is propelled into the large
arteries leaving the heart.
What does the tunica interna line?
The lumen (cavity), the interior of the vessels
What is the tunica interna?
thin layer of endothelium
(squamous epithelial
cells) resting on a scanty
layer of loose connective
tissue.
What is the tunica media?
bulky middle coat made
up of smooth muscle and
elastic tissue.
What do some larger arteries have?
Elastic laminae
What is elastic laminae?
complete sheets of
elastic tissue in
addition to the
scattered elastic
fibers.
What are capillary beds?
the tiny interweaving
network of capillaries.
What is microcirculation?
the flow of blood from
an arteriole to a
venule that is through
a capillary bed
What do capillary beds consist of?
Vascular shunt and true capillaries
What are vascular shunts?
a vessel that directly
connects the
arteriole to the
venule at opposite
ends of the bed
What do precapillary sphincters do?
surrounds the root of each
true capillary and acts as
a valve to regulate the flow
of blood into the capillary.
What are the two possible routes of blood flowing through a terminal arteriole?
Through the true capillaries or through the shunt
What happens when the precapillary sphincters are relaxed (open)?
Blood flows through the true capillaries and takes part in exchanges with tissue cells
What happens when the precapillary sphincters are contracted (closed)?
Blood flows through the shunts and bypasses the tissue cells
