Pathway of Blood to the Heart Flashcards
How much blood will the heart push out in one day? How much is that? (2)
- The body’s supply of blood
- Around six quarts
How much will will the heart pump blood through the vessels every day? How much is it actually pumping? (2)
- Through the blood vessels over 1,000 times
- Actually pumping about 6000 quarts of blood in a single day
How many times do the atrial cells beat per minute? How many times do the ventricular cells contract per minute? (2)
- 60 times per minute
- More slowly, about 20 to 40 times per minute
What does the heart need to be an efficient pump?
A unified control system
Within what do the purkinje fibers spread?
Spread within the muscle of the ventricle walls
What does the AV valve system cause for heart muscles? In what direction? From what to the ventricles? (3)
- Causes heart muscle depolarization
- In only one direction
- From atria to the ventricles
What contraction rate do the AV valves have on the heart? What does this enable the heart to do? (2)
- Rate of 75 beats per minute
- Beat as a coordinated unit
What does this contraction of the AV valves eject blood into?
The arteries leaving the heart
What is the clinical procedure for mapping the electrical activity of the heart?
Electrocardiography
In a healthy heart, how do the atria contract?
Simultaneously (together)
As the atria relax, what contracts?
Ventricles contract
What does systole mean?
Contraction
What does diastole mean?
Relaxation
What cycle refers to the events of one complete heartbeat
Cardiac cycle
What do the atria and ventricles both do?
Both contract then relax
How long is the cardiac cycle based on the average heart beating 75 times per minute?
0.8 seconds
What are three periods during which the cardiac cycle takes place? (3)
- Mid-to-late diastole
- Ventricular systole
- Early diastole
What happens when ventricular contraction begins? What sound is created as the AV valves close? (2)
- Pressure within the ventricles increases rapidly
- Creating the first heart sound - “lub”
What ends as early diastole begins? What relaxes? (2)
- Systole ends
- Ventricles relax
During diastole, what sound is created as the semilunar valves snap shut?
Create the second heart sound - “dub”
What is the amount of blood pumped our of each side of the heart (actually each ventricle) in one minute called?
Cardiac output (CO)
What is cardiac output the product of?
(HR x SV = CO) (2)
- Heart rate (HR)
- Stroke volume (SV)
What is the normal resting heart rate? What is the normal resting stroke volume? (2)
- Heart rate: 75 beats per minute
- Stroke volume: 70 ml per beat
What system does blood that circulates inside the blood vessel form? What kind of transport system is it? (2)
- Vascular system
- Closed transport system
As the heart beats, what is the blood propelled into that is leaving the heart?
Large arteries
What does the tunica interna line?
- Lines the lumen
What is the lumen?
Interior of the vessels
Thin layer of endothelium resting on a scanty layer of loose connective tissue - lumen. What kind of cells are they?
Squamous epithelial cells
What is the bulky middle coat made up of smooth muscle and elastic tissue?
Tunica media
What do some of the larger arteries have?
Elastic laminae
What is elastic laminae?
Complete sheets of elastic tissue in addition to the scattered elastic fibers
Tiny interweaving network of capillaries
Capillary beds
The flow of blood from an arteriole to a venule that is through a capillary bed
Microcirculation
A vessel that directly connects the arteriole to the venule at opposite ends of the bed (one of the capillary bed types of blood vessels)
Vascular shunt
Surrounds the root of each true capillary and acts as a valve to regulate the flow of blood into the capillary
Precapillary sphincter
Blood flowing through a terminal arteriole may take one of two routes (2)
- Through the true capillaries
- Through the shunt
Blood flows through the true capillaries and takes part in exchanges with tissue cells with the precapillary sphincters are:
Relaxed (open)
Blood flows through the shunts and bypasses the tissue cells when the precapillary sphincters are:
Contracted (closed)
