Chapter 21 - The Cardiovascular System: Blood Vessels Flashcards
This is all the events associated with one heartbeat
Cardiac cycle
The cardiac cycle consists of what?
Systole & diastole of the atria and systole & diastole of the ventricles
When the heart rate is 75 beats per minutes how long does the cardiac cycle last?
.8 seconds
This is the volume of blood ejected per beat from each ventricle.
Stroke volume
What is normal stroke volume?
70mL (a little more than 2 oz)
This is the volume of blood ejected from the left ventricle into the aorta each minute (or from the right ventricle into the pulmonary trunk each minute)
Cardiac output
This Is the number of heartbeats per minute.
Heart rate
What is the normal heart rate?
75 beats per minute.
What is the formula for cardiac output?
Stroke volume X heart rate = cardiac output
Any condition that effects heart rate can also effect?
Cardiac output
List some examples of things that effect heart rate.
Age, gender, physical fitness, body temperature, and hormones
This is an abnormally rapid resting heart rate (over 100 beats/minute)
Tachycardia
This is a a slow resting heart rate (under 50 beats/minute)
Bradycardia
What are the 5 main types of blood vessels?
Arteries, arterioles, capillaries, venues, veins
These blood vessels carry blood away from the heart to other organs.
Arteries
These blood vessels are small arteries that deliver blood to capillaries
Arterioles
These blood vessels are microscopic blood vessels located between arterioles and venules
Capillaries
These are small veins that collect blood from capillaries
Venules
These carry blood from organs back to the heart
Veins
Arteries carry blood away from the heart through?
The hollow lumen
What are the 3 wall layers that make up arteries?
Tunica interna, tunica media, tunica externa
This is the innermost coat of an artery. It contains a lining of endothelium, a basement membrane, and an internal elastic layer
Tunica interna
This is the middle coat and thickest layer of the artery wall. I consists of elastic fibers and circular smooth muscle fibers
Tunica media
This is the outer layer of the artery wall. It is composed of elastic and collagen fibers
Tunica externa
Increased sympathetic stimulation from the ANS causes this as smooth muscle in the tunica media contractions. This decreases the diameter of the lumen of an artery.
Vasoconstriction
Decreases sympathetic stimulation causes this as the smooth muscle relaxes. This increases the diameter of the lumen.
Vasodilation
Blood flows from arterioles to venules through?
Capillaries
The capillaries are found near?
Almost every cell in the body
These are involved the exchange of nutrients and oxygen with wastes and CO2 between the blood and tissue cells through interstitial fluid
Capillaries
The walls of the capillaries are composed of? They have no?
Only a layer of endothelium an a basement membrane / tunica media or tunica externa
Capillaries form?
Extensive branching networks
Veins have the same three layers in their walls as? These layers are?
Arteries / tunic interna, tunica media, tunica externa
Why are the walls of veins thinner than that of arteries?
The walls have less muscle and fewer elastic fibers.
The lumens in veins are what sized compared to arteries?
Larger
Veins appear how in relation to arteries?
Seem what flattened
Veins have valves that do what?
Prevent the backward flow of blood.
What percentage of an individual’s blood volume is in veins and venules while at rest? These vessels are called?
64% / blood reservoirs
The volume of blood that flows back to the heart (into the right atrium) through systemic veins is called?
Venous return