Human Circulation
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Transcript of Human Circulation
Human CirculationHuman CirculationA closer look
ContentsContents1. Cardiac cycle2. Maintenance of heartbeat3. Principles governing blood
circulation4. Blood composition and function5. Cardiovascular disease6. Lymphatic system
Cardiac cycle Cardiac cycle complete sequence of pumping and fillingcomplete sequence of pumping and filling
Electrical Electrical activity of the activity of the heartheart
1 - Sinoatrial node (Pacemaker)2 - Atrioventricular node3 - Atrioventricular Bundle (Bundle of His)4 - Left & Right Bundle branches5 - Bundle Branches 6 - Purkinje fibers
PulsePulse Stretching of arteries as
an effect of heartbeat Pressure waves moving
the artery walls when blood moves into aorta
Usually accurate measure of heart rate
Normal resting pulse is 60-100 bpm
Common pulse points1. Temporal artery
3. Carotid artery
4. Brachial artery
5. Radial artery
Cardiac outputCardiac output Total volume of blood
pumped by the left ventricle per minute◦ Heart rate (HR) #
beats per minute◦ Stroke volume (SV)
mL◦ Product gives the
cardiac output (Q)◦ Average adult
Q = HR x SV
= 70 beats/min x 75 mL/beat
= 5.25 L/min
Maximum HR = 200-your ageTraining heart rate is 75% MHR
e.g. 200-15 = 185 * 0.75 =
139 beats/min 20 minutes, 3x a
week
Blood vessel structureBlood vessel structure
Physical principles governing blood Physical principles governing blood circulationcirculation Blood flow velocity
◦ Aorta (30 cm/s)
◦ Capillaries (0.026 cm/s)
Law of continuity◦ Volume of flow per second must be constant through the entire pipe
◦ Total cross-sectional area of the capillaries determines flow rate
◦ Blood flow slows down in capillary beds
Blood pressureBlood pressure Force exerted by
blood on walls of vessels
Pressure decreases from arteries to veins
Determined by cardiac output and peripheral resistance by arterioles
Arterial pressure measured by a sphygmomanometer
Systolic/Diastolic (mmHg)
Factors◦ Heart rate◦ Blood volume◦ Resistance of vessels◦ Viscosity
Blood composition and Blood composition and functionfunction
Cardiovascular diseaseCardiovascular disease Cardiovascular disease
(>50% of all deaths) Hypercholesterolemia:
LDL, HDL Hypertension: high blood
pressure Atherosclerosis: arterial
plaques deposit Arteriosclerosis: plaque
hardening by calcium deposits
Heart attack- death of cardiac tissue due to coronary blockage
Stroke- death of nervous tissue in brain due to arterial blockage
Lymphatic SystemLymphatic SystemFunctions
◦ Returns excess body fluid to blood◦ Transports fats from intestines to blood◦ Defense
Anatomy◦ Lymph nodes scattered throughout body
(thymus, spleen)◦ Vessels
Check-up QuizCheck-up Quiz
1. What is ventricular systole?2. What makes the “lub dub” sound?3. Give one difference between an
artery, a capillary, and a vein.4. Name one factor that can raise
blood pressure.5. Name one substance that should
be present before a blood clot can form.