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Mitral valve prolapse
when one valve doesn't close all the way
pathway of blood through the heart
vena cava- right atrium- tricuspid valve- right ventricle- pulmonary semilunar valve- pulmonary arteries- lungs- pulmonary veins- left atrium- bicuspid (mitral valve)- left ventricle- aorta
microscopic structure of the heart
striated and interconnected disks.
What is the inherent rythym of the SA node compared to the bottom of the heart?
60 bpm vs 30 bpm
What is the typical electrical pathway of the heart?
SA node- AV node- bundle of HIS- purkinje fibers
What arteries supply blood to the heart?
- Left coronary:
- -circumflex: LA/ lateral wall of left ventricle
- -anterior descending: ventricular septum/ anterior surface of LV
- Right coronary: RA/inferior wall of RV
coronary artery disease
when beat doesn't originate from SA node
Systole (what it is and how long)
- time during contraction
- 1st sound heard, 1/3 time
diastole (what it is and how long)
- time between contractions, 2/3 time
- more consistent
- records QRS waves as a function of time
on an ECG, how many large boxes make up one second?
how many large boxes on an ECG make up 1 mV?
- beginning of P to beginning of QRS
- time for stimulus to go SA throug AV junction
ventricular depolarization and atrial repolarization
- rarely seen
- final component of ventricular repolarization
time for one HR cycle
How many leads are in a typical ECG?
- type I: frontal, horizontal, bipolar, positive =>
- type II: frontal, diagonal neg slope, bipolar, positive at bottom
- type III: frontal, diagonal pos slope, bipolar, positive at bottom
- AVr: frontal, opposite to type II, unipolar, positive at top
- AVl: frontal, opposite to type III, unipolar, positive at top
- AVf: frontal, perpindicular to type I, positive at bottom
- V1: transverse, right of sternum
- V2: left of sternum
- V3: between V2 and V4
- V4: mid clavicular
- V5: left of v4
- V6: left of V5
cardiac output (Q)
amount of blood ejected by the heart/min
Q at rest
5-6 L/min for both trained and untrained
- >30 L/min trained
- 20-25 L/min untrained
- 5-6 fold from rest
do males or females have higher max Q?
males, but they also have lower submaximal VO2
what equation is used to determine Q
Q (L/min) = SV (ml/beat) * HR (b/min)
What is stroke volume?
- ml of blood ejected per beat.
- increased from rest to moderate exercise in non-athletes, and then plateaus
- changes with posture
Is your stroke volume higher lying down or sitting?
- lying down
- Q is higher as well lying down, HR is lower lying down
Which of the three increases in a linear fashion with increased intensity?
Q, HR, SV
Q and HR
what is the RHR in a trained and untrained individual?
- trained: 40
- untrained: 70-90
Since HR lowers with training, what typically happens with SV?
What happens to the Q, HR, and SV as you exercise past 30 min?
- Q is maintained
- SV gradually falls
- HR gradually rises
what are the three ways venous blood returns to the heart?
- muscle pump
- respiratory pump
at rest and exercise, how much blood goes to the muscles?
- rest: 20%
- max exercise: 80%
Why does the skin decrease in % Q distribution between light and moderate exercise?
Because the body starts to sweat
As exercise increases, what happens to the amount of blood to the brain?
nothing, the percent distribution is lowered, but the same amount is supplied there.
Blood flow distribution is a result of what?
- autoregulation: local
- -O2 demand
- -reflex vasodilation to working muscles
- Extrinsic Neural Control: not local
- -sympathetic vasoconstriction
- -sympathectic stimulation in heart causes vasodilation
Why does blood flow increase in the heart during exercise?
to increase oxygen consumption
What is the equation to determine VO2?
- VO2 = SV * HR * a-vO2 diff
- VO2 = delivery * extraction
in a person with hypertension (HBP), what drop can someone expect during exercise in mmHg?
- 8-10 mmHg
- moderate exercise is more effective than vigorous exercise
what 3 functions concerning blood are important to exercise physiology?
- temperature regulation
- acid-base (pH) balance
seems when there's anemia, but just more plasma
composition of blood
- 55-60% plasma
- 40-45% formed elements
how can you increase blood viscosity and what is the benefit?
increase hematocrit and it increases O2 transportation
What is plasma made of?
- 90% H2O
- 7% plasma proteins
- 3% other
What are formed elements composed of?
- >99% red blood cells
- <1% white blood cells and platelets
How do you measure blood O2 content and what are the values at rest and exercise?
- a-vO2 diff = arteriol - venous
- rest: 6 mL
- exercise: 16-18 mL
What happens to Plasma Volume (PV) with exercise?
- decreases because of pressure pushing it out of capillaries, and sweating and breathing causes loss of fluid.
- can lose up to 10-20%
- decrease impairs performance
when PV decreases, O2 carrying capacity increases