Week 5 Study Guide
Electrocardiogram (EKG)
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‘K’ comes from German elek
Records the electrical changes in the heart.
P wave= Depolarization of the Atrium (right after the electrical off-shoot from the SinoAtrial
Node). This is also the Systole of the Atrium.
QRS wave= Depolarization of the Ventricles. Also, the Systole of the Ventricles. Atrium
repolarizes during this time and is in diastole.
o The first heartbeat sound occurs right after the peak of the R.
T Wave= Repolarization of the ventricles/diastole of the ventricles.
o The second heartbeat sound occurs after the T wave.
Arrythmia (a= without; rythm= rhythm; -ia=condition
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Heartbeat with an irregular rhythm; caused by defects in the intrinsic conduction within the
myocardium.
Can be caused by caffeine, nicotine, anxiety, potassium deficiency
Heart Block- the propagation (spreading/distribution) of the action potential becomes slowed or
blocked altogether. Most commonly affected area is the Atrioventricular Node (AV)
Atrial Flutter- The abnormally rapid contractions of the atrium. This can be 300 contractions per
minute.
Atrial Fibrillation- Atrium muscle fibers contract at different times.
Ventricular Fibrillation- Ventricle muscle fibers contract at different times.
Cardiac Output (CO)
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Volume of blood pumped out of the left ventricle per minute
HR (heart rate) X SV (stroke volume) = Cardio Output
Ex. 75bpm X 70mL/beat = 5250mL/min
Cardiac Reserve= difference between resting CO & maximal CO (Cardiac reserve is higher among
athletes
Stroke Volume
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Volume of blood pumped out of left ventricle per beat.
Determinants:
o Contraction Strength
o Increase volume or speed of venous return (raises stroke volume)
o Low venous return (decreases stroke volume)
Homeostatic Imbalances of CO
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Regular blood circulation maintains a balance of CO and venous return
Heart congestion= when CO of heart is so low that it cannot keep homeostasis
o Weakens myocardium
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Can cause coronary atherosclerosis, constant high blood pressure, Myocardium
Infarction, and cardiomyopathy
Left side congestion= pulmonary congestion
Right side of congestion= peripheral congestion
Exercise & Aerobics
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Aerobics- Activities that works large body muscles for at least 20 minutes 3-4 per week such as
swimming, running, bicycling, and skiing.
Training increases the oxygen demand of the muscles and also increases CO after training.
Hemoglobin level rises, capillaries increase in skeletal muscle, metabolism increases, anxiety and
depression decreases, blood pressure is lowered, and weight can be better controlled.
Elevating Circulation
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Pulse- a traveling wave of pressure from the expansion and recoil of the elastic blood arteries
after each left ventricular systole.
Pulse is strongest nearest the heart. Typically the same as the heart rate- 70-80 bpm.
Tachycardia- (tachy= fast/rapid; card/i= heart; -ia=condition) rapid heart rate over 100 bpm
Bradycardia- (brady= slow) slow resting beat under 60bpm; common in endurance athletes
Arteries
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Temporal Artery- by the temporal lobe
Facial Artery- upon the Ramus of the Mandible
Carotid Artery- close to the sternocleidomastoid muscle
Brachial Artery- opposite side of the elbow
Radial Artery- between the brachioradialis muscle and the extensor digitorum muscle.
Femoral Artery- around the inguinal region.
Popliteal Artery- by popliteal muscle
Posterior Tibial Artery- above the medial malleolus
Dorsalis Pedis Artery- along the extensor digitorum longus.
Blood Pressure
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Hydrostatic pressure against the arterial wall; measured in mmHg
The different blood pressure within the blood vessels is what moves the blood through the body
o Blood volume
o Blood viscosity (resistance to flow)
o Vessel elasticity
o Cardiac output (CO)
o Peripheral resistance
Systemic Blood Pressure
o High to Low Gradient; heart pumps creates flow
o Arterial Blood Pressure- 2 factors
 Maximum elasticity of the arteries near the heart
 Volume of blood being forced into them
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o BP rises and falls systematically.
Measuring BP
o Systolic Pressure- pressure against the arterial walls during left ventricle systole;
typically 120mmHg
o Diastolic Pressure- relaxed state of both ventricles & atriums. Walls of arteries contract
to move the blood. Typically 80mmHg
o Measuring Directly- Hg manometer (pressure measuring device) hooked up directly to
artery (typically carotid artery)
o Measuring Indirectly- Using a sphygmomanometer (Sphygm/o= pulse) measures from
the brachial arety
Pulse Pressure
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Difference between the systolic and diastolic pressures
Throbbing sensation in arteries per systole
40mmHg
Venous Blood Pressure
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Lowest pressure found in veins
Venous return= volume of blood returning to the heart- changes depending on the pressure
from the venules
o Resistance in veins is very low; keeps up with left ventricle outlet
o High pressure in R. Atrium= Lower venous return
o 60% of blood at rest is in systemic veins and venules
o Blood reservoirs- blood from the veins and venules can be redirected as needed
Capillary Blood Pressure
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Low pressure for gas change and because the capillaries are fragile
Low velocity (rate of blood flow) due to large surface area for gas exchange
Regulation of Blood Pressure
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Neural Regulationo Baroreceptors -> inhibits cardioaccelatory centers or stimulates cardioinhibitory centers
o Chemorecptors ->
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Hormonal Regulation
o Norepinephrine & Epinephrine- increases the blood pressure when there is an
increased heart rate & contractility
o Angiotensin II, antidiuretic hormone, norepinephrine, epinephrine increase blood
pressure when there is vasoconstriction
o Atrial natriuretic peptide, epinephrine, and nitic oxide decreases blood pressure during
vasodilation
o Aldosterone, antidiuretic hormone increases the blood pressure when blood volume
decreases
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o Atrial natriuretic peptide decreases blood pressure when blood volume increases
Local Regulation
o Surrounded tissues adjust blood flow due to gas exchange
Capillary Exchange
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Movement into and out of the capillaries
3 modes of exit:
o Diffusion- Most important- O2, glucose, hormones, and all plasma solubles except larger
proteins
o Transcytosis- larger proteins enter a vesicle through endocytosis, travel through the
endothelial cells, and exit through exocytosis.
o Bulk flow- large number of ions, molecules, or particles move down the gradient
Edema
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Increase of interstitial fluid volume from an increase of filtration
o Hypertension, increased permeabilities of capillaries
o Inadequate reabsorption of the filtration
Cardiovascular Diseases
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Hypertension
o High Blood pressure, increases peripheral resistance,
o Strains the heart and can damage the walls of the arteries
o Prolonged hypertension can result in heart failure, stroke, or renal failure
o Risk factors:
1. high sodium, high cholesterol, and high saturated fats
2. obesity
3. 40 years or older
4. Race- Blacks are more susceptible for hypertension
5. Hereditary
6. Stress
7. Smoking nicotine
8. Exercise
Secondary Hypertension
o Excessive renin in urine output, arteriosclerosis
Atherosclerosis
o Walls of the arteries become thicken with plaque. The plaque becomes hardend and the
artery loses its elasticity. Blood flow decreases and eventually becomes clogged. Most
commonly affected areas are the aorta & coronary arteries
o Balloon angioplasty- insertion of a miniature balloon in the artery that, when inflated,
pushes the arterial walls out to their normal size, including the damaged parts of the
wall from plaque and build up. This allows normal blood flow through the artery.
Cholesterol
o Provides structure for bile salts, steroids hormones, vitamin D, becomes a majot
component of the plasma membrane,
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Triglycerides and cholesterol are not soluble in water and thus need to be escorted
through the blood by lipid-protein complexes call Lipoproteins.
1. High plasma cholesterol levels can be more than 200mmHg
2. LDL (low ) transport the cholesterol on the walls of the arteries
3. HDL (high ) transports cholesterol to the liver.
 35-60mmHg Is ok
Varicose vein
o Twisted and dilated veins; malfunction of the venous valves.
Aneurysm
o Expansion of an arterial wall prone to rupturing
o Most commonly affected areas are the abdominal aorta, arteries of the brain, and the
kidneys
Multiple Choice1.Where does the depolarization of the ventricles occur?
a)
b)
c)
d)
T wave
P wave
QRS wave
Surfer’s Wave
2. Which of the following is not an artery?
a)
b)
c)
d)
Carotid
Brachial
Axillary
Posterior Tibial
3. What is the purpose of the baroreceptor when stimulated?
a) To stimulate the cardioaccelerator
b) To inhibit the cardioaccelerator
c) To stimulate the cardioinhibitory center
4. T_/F_ A risk factor of hypertension is exercise
5. T_/F_ Blood reservoirs can be found in the capillaries
6. T_/F_ Systemic Circuit starts at the left ventricle and Pulmonary Circuit stems from the right ventricle
7. List the cycle of blood flow starting from the Right Atrium.
8. Why would the pulse you feel in the brachial artery come after the actual heart beat?
9. How would hormones help the circulatory system when the blood pressure & volume was low?