CARDIAC CYCLE
When one uses the term "diastole" on its own, this usually refers to THIS happening in the cardiac cycle
_VENTRICULAR_ RELAXATION
Define "pulse"
and
Bonus Q: Do veins have a "pulse" (yes or no)?
"Alternating surges of pressure...in an artery that occur with each expansion and relaxation of the left ventricle"
Bonus answer: NO
The contraction of the heart muscles in the atria (atrial systole) is only responsible for 20% of ventricular filling, the other 80% is more "passive" filling during ventricular diastole. When does atrial contraction take place, near the beginning of or near the end of ventricular diastole?
This is the name of the smallest blood vessels in the body with exceedingly thin walls (practically only endothelium, with a thin basement membrane of CT) to allow for easy gas and nutrient exchange.
Bonus question: Is the relative blood velocity FASTER or SLOWER in these vessels, and why?
CAPILLARIES
Although they are small so one would think they would have a higher velocity, they have a much larger total X-area than other vessels (since there are millions of them!), so they have the SLOWEST blood velocity. This is important, because high velocity could damage the thin capillaries, and we need slow velocity to allow enough time for good gas and nutrient exchange.
A person's cardiac muscle's action potential (AP) lasts for 200 ms (milliseconds, each of which is 1/1000 of a sec), and their skeletal muscle's AP lasts 2 ms. Which is longer? Why?
Ejection of blood out of the ventricles, from the R ventricle into the pulmonary arteries and from the L ventricle into the aorta, takes place during which phase of the cardiac cycle?
[VENTRICULAR] SYSTOLE
Define what is meant by "cardiac cycle"
"All the events associated with blood flow through the heart for one complete heart beat: atrial systole and diastole followed by ventricular systole and diastole [and the isometric phases in between]."
What causes the Semi-Lunar valves (the Pulmonary and Aortic valves) to open, and what "PHASE" begins when they do?
Increasing pressure in the ventricles following ventricular depolarization (the QRS wave on the EKG) rises and rises until it exceeds the "afterload" pressure of the large arteries exciting from them (e.g. aorta, often around 80mmHg at the end of diastole). When pressure inside the ventricle is higher, it forces the SL valves open, starting the "VENTRICULAR EJECTION" phase of systole.
Explain the difference between an artery and an arteriole. Do they both have smooth muscle in their "tunica media" middle layer?
Arterioles are much SMALLER than Arteries, they are the intermediate step before one reaches the capillary level. Arterioles also have less elastic tissue.
YES, they both have smooth muscle as part of their middle layer, the tunica media. This muscle is especially important in ARTERIOLES, since they are responsible for regulating minute to minute blood flow and pressure through their vasoconstriction or vasodilation.
If a person's End Diastolic Volume (EDV) is 130 mL, and their End Systolic Volume (ESV) is 60 mL, then what is their Stroke Volume?
Remember that SV=EDV-ESV,
so in this case
130-60=70mL for the stroke volume (SV)
What is the name for the cardiac cycle in which the AV valves are open and the SL valves are closed
[VENTRICULAR] DIASTOLE
Define "apical pulse"
The counting of the number of the heart's beats per minute that one gets by listing to the APEX of the heart (at the 5th intercostal space in line with the middle of the clavicle, usually just below the breast) that is the portion of the heart closest to the superficial anterior surface. Fun fact: the apical pulse may be slightly faster than the radial pulse of the same individual. Note that one also hears the heart sounds of the mitral valve over the heart apex.
Explain what is meant by the term ISOVOLUMETRIC, and how does it relate to EDV and ESV?
It means the SAME VOLUME, and we find it during the two very short periods where all four of the heart valves are closed: after the AV valves close off (thus no more blood can come into the ventricles) representing the constant End Diastolic Volume before the SL valves open and eject blood from ventricles, and then after the SL valves close after that ejection completes (60% ejected out of a healthy heart, but no more of the remaining 40% can exit), representing the end of [ventricular] systole and End Systolic Volume.
Name at least THREE pulse points (also called "pressure points," places on the superficial surface of the body where the PULSE is most easily palpated (felt through simple touch).
A person has a Stroke Volume (SV) of 70 mL per heart beat, and they have a resting heart rate (HR) beating at 100 beats per minute (fairly fast, on the border of "tachycardia" which is anything>100 bpm). Calculate their Cardiac Output (CO), giving your answer in LITERS/min.
Remember that CO=SVxHR,
so in this case 70ml/beat x 100 beats/min yields an answer of 7000 mL per minute. We're not done yet though, because the question asks for the final answer to be given in Liters, not milliLiters. Since 1000 mL = 1L, 7000/1000= a final answer of
7.0 L/min
This is the term for the two short portions of the cardiac cycle in which the blood volume in the ventricles remains constant and during which the two heart sounds (LUB and DUP) resonate
ISOMETRIC
(isometric contraction and isometric relaxation)
Define "auricle" when it comes to the anatomical structure of the heart
SMALL, WRINKLED PROTRUDING APPENDAGES WHICH INCREASE THE ATRIAL VOLUME SOMEWHAT (usually filling last after the rest of the atrium is full)
What causes the AV valves (Tricuspid and Mitral/Bicuspid) to open, and what PHASE is initiated once they do?
All during ventricular systole, the atria have been in diastole. They have been filling with blood and the intra-atrial pressure has been rising. When blood pressure on the atrial side of the AV valves exceeds that in the ventricles, the AV valves are forced open and VENTRICULAR FILLING phase of ventricular diastole begins.
Name at least one part of the body in which one might find SINUSOID CAPILLARIES, and explain why (that is, how does the structure of those types of capillaries support the functional needs of that body part?)
Sinusoid capillaries are found in LIVER, BONE MARROW, SPLEEN, and ADRENAL MEDULLA.
The large "intercellular cleft" openings in these capillaries allow LARGE molecules and even CELLS to pass across their walls, especially useful in locations of the body whose job is to produce or filter out blood cells.
At the ateriole-end at the start of a capillary, the capillary Hydrostatic Pressure (HPc) is 35mmHg, and its Osmotic Pressure (OPc) is 26mmHg. From the interstitial side, HPif is basically 0mmHg, and OPif is 1mmHg. What is the Net Filtration Pressure (NFP)?Bonus: will fluid move OUT OF or INTO the capillary at this point?
(35-0)+(26-1)=35-25= a positive 10mmHg net outward pressure. Since this final NFP answer is positive, fluid moves from the capillary OUTWARD to the interstitial space. At the other (venule) end of the capillary, once total HP has dropped BELOW total oncotic pressure (for example, say 17 compared to 25), the resulting NFP negative number (17-25= -8) means fluid moves from the interstitial space INTO the capillary.
This phase of the cardiac cycle contains the "diacrotic notch" the little bump up in the aortic pressure that is caused by blood surging back against the aortic SL valve on its closing
ISOMETRIC RELAXATION
that immediately follows the end of ventricular systole
Define "cardiac skeleton," and explain its anatomical purpose with reference to the functioning of the heart
"Connective tissue (CT) fibers...that reinforce the myocardium internally and anchor the cardiac muscle fibers.... Additionally, because CT is not electrically excitable, the cardiac skeleton limits the spread of action potentials to specific pathways in the heart [especially keeping APs from prematurely spreading from the atrial myocardium to ventricular myocardium except through the AV node and bundle].
Note: Despite "skeleton" in the name, there is nothing bony about it
The two major "heart sounds" LUB and DUP are caused by the closing of each of the two sets of heart valves, and they resonate during WHICH STAGE(S) of the cardiac cycle.
They both take place during ISOMETRIC phases: the 1st sound (S1, LUB) during ISOMETRIC CONTRACTION phase ("contraction" referring to the fact that the ventricles are contracting now, but the SL valves are not yet open until the pressure rises high enough), and the 2nd sound (S2, DUP) during ISOMETRIC RELAXATION phase (closing of SL valves)
Pressure on the venous end of the system is normally too low to promote adequate return of venous blood to the heart, so the body has three functional systems that help support venous return: pressure changes from the respiratory system as we breathe, sympathetic vasoconstriction of smooth muscle in veins, and THIS THIRD SYSTEM (hint: also related to muscles)
How does one calculate the Pulse Pressure?
Bonus points: How can one use the Pulse Pressure together with diastolic pressure to calculate Mean Arterial Pressure (M.A.P.)?
Pulse Pressure is the difference between systolic and diastolic, simply calculated by subtracting diastolic pressure from systolic pressure (e.g. 120-80=40).
It can be used to calculate M.A.P. through this equation: MAP = diastolic + (pulse pressure/3), for example 80+(40/3) = 93. The MAP will always be closer to the diastolic pressure than the systolic, because the heart spends about twice as long in diastole than systole.