Unit 4 Flashcards
The compartment labeled “A” in the above diagram is the _____. It receives venous (deoxygenated) blood from the body.
right atrium
The compartment labeled “B” in the above diagram is the _____. It contracts to send blood to the lungs for gas exchange.
right ventricle
The compartment labeled “C” in the above diagram is the _____. It receives oxygenated blood from the lungs.
left atrium
The compartment labeled “D” in the above diagram is the _____. It contracts to send blood to the entire body.
left atrium
The vessel labeled “E” in the above diagram is the ______. It is the initial conduit for deoxygenated blood to pass to the lungs.
pulmonary artery
The vessel labeled “F” in the above diagram is the ______. It is the initial conduit for all oxygenated blood to pass to the entire body.
aorta
The valve labeled “G” is generally called a _______. Don’t worry about left or right on this one. These one-way valves connect the top chambers of heart to the bottom ones.
Atrioventricular (AV) valve
The valve labeled “H” is generally called a _______. Don’t worry about left or right on this one. These one-way valves prevent back-flow of blood from adjacent vessels when the bottom chambers relax.
semilunar valve
OK, enough with that figure above. Let’s talk more about the myocardial cells. Cardiac muscle cells are held together, end-to-end, at complex junctions called ________ that consist of interdigitated
membranes.
intercalated disks
Within the junctions mentioned in the previous question (intercalated disks), the cells are physically tethered by these strong connections that allow force created in one cell to be transferred to the adjacent cell.
demosomes
These components of the junctions mentioned in Question 9 allow cardiac muscle cells to be electrically connected. These direct conduits
between myocardial cells allow waves of depolarization of to pass rapidly between cells, causing them to contract almost simultaneously.
gap junctions
These specific myocardial cells make up ~99% of the heart, are striated muscle, and have thick and thin filaments organized into sarcomeres.
contractile cells
These specific myocardial cells make up ~1% of the heart, and mostly lack thick and thin filaments. Rather they are specialized for passing
electrical signals around the heart.
conducting (autorhythmic) cells
This general category of vessel directly returns blood back to the heart atria.
veins
This general category of vessels directly receives blood from the heart ventricles.
arteries
These blood vessels are the primary site of vasoconstriction and vasodilation because they contain large amounts of smooth muscle.
arterioles
These blood vessels are where gas, nutrient, and waste exchange occurs in body tissues.
capillaries
These blood vessels receive deoxygenated blood from the vessels named in the previous question.
venules
The circuit of the cardiovascular system that conducts deoxygenated blood from the heart to the lungs and returns oxygenated blood back to the heart is called the _______.
pulmonary circuit
The circuit of the cardiovascular system that conducts oxygenated blood from the heart to body tissues and returns deoxygenated blood
back to the heart is called the _______.
systemic circuit
______ defines the amount of blood that is pumped by one ventricle during a single contraction.
stroke volume
The total volume of blood pumped by one ventricle during a given period of time (usually 1 minute) is called the ______.
cardiac output
This concept explains that the heart must pump all the blood that returns to it AND the force of heart contraction is determined by the volume of blood returning to it at any given moment.
Frank-Starling Law
______ is a term that describes all the electrical and physical events that happen in the heart during one contraction-relaxation cycle.
cardiac cycle
If we count the number of contraction – relaxation cycles that happen in 1 minute, that defines a person’s _______.
heart rate
The volume of blood entering the heart from the venous circulation at any given moment is technically called _______.
venous return
______ defines the volume of blood left in a ventricle at the end of its contraction phase.
end-systolic volume
______ defines the maximum amount of blood that a ventricle can hold when it is fully relaxed.
end-diastolic volume
______ describes the time when a heart chamber (atria or ventricles) are contracting and pumping blood.
systole
______ describes the time when a heart chamber (atria or ventricles) are relaxing and filling with blood.
diastole
In the SA Node figure above, these channels are open at the stage marked “4”.
If channels
The channels in the previous question got their name due to their
“funny” behavior of allowing both Na+ and K+ ions to pass through. However, these channels are MORE permeable to one of these ions, and that’s what leads to the net depolarization seen in stage “4” of the
SA Node diagram. Which ION are these channels more permeable to?
Na+
In the SA Node diagram above, these channels are open in abundance
at the stage marked “0”. No wonder there is a big depolarization, eh? Make sure to choose a type of channel from the list, not an ion.
voltage-gated Ca2+ channels
At the peak of the depolarization of a conducting cell, the channels in
the previous question close and these channels open, resulting in the
repolarization phase marked with a “3” in the left diagram above. Make sure to choose a type of channel from the list, not an ion.
slow K+ channels
In the SA Node diagram above, the part of the action potential marked with the “4” gets a special name to denote how it automatically climbs towards threshold. What is that special name?
pacemaker potential
OK, the remaining questions will target the right diagram. They sure
look cool, huh? First off, what is their resting membrane potential (phase marked “4” in above diagram)?
-90 mV
(Right diagram) . When contractile cells receive a depolarization from an adjacent
conducting or contractile cell, they immediately depolarize (stage marked “0” above) through the opening of these channels. Make sure to choose a type of channel from the list, not an ion.
Kvoltage-gated Na+ channels
(Right diagram) When the membrane potential reaches +20 mV (stage marked “1” above), channels for this ION open and close very quickly, causing a very brief repolarization.
K+
(Right diagram) After this brief repolarization, the plateau phase (marked “2” above) ensues and this flattening of the action potential is due to what kind of channels opening. Make sure to choose a type of channel from the list, not an ion. The ion that moves in from the interstitial fluid will lead to power strokes in the contractile cell and sarcomere shortening. See Figure 14.9 for more on this and we will talk about it in lecture.
voltage-gated Ca2+ channels
–> figure 14.9:
(Right diagram) After the channels mentioned in the previous question close, the cell will rapidly repolarize (phase “3” in the diagram above). This change in membrane potential is due to the opening of what kind of channels? Make sure to choose a type of channel from the list, not an ion.
slow K+ channels
These blood vessels have the smallest diameter. They are also the site of exchange for nutrients, wastes, and signal molecules between the
blood and body tissues since they are composed only of a single layer of loosely connected endothelial cells.
capillaries
These blood vessels deliver blood to specific tissues and the smooth muscle cells embedded in their walls give them variable resistance. These characteristics make them ideal for fine tuning blood flow to meet the metabolic demands of different tissues around the body.
arterioles
These blood vessels collect blood just after it has had a chance to exchange nutrients, wastes, and signal molecules with body tissues and start its return journey to the heart.
venules
