1. Human Circulation
A closer look

2. Contents Cardiac cycle Maintenance of heartbeat
Principles governing blood circulation
Blood composition and function
Cardiovascular disease
Lymphatic system

3. Cardiac cycle complete sequence of pumping and filling

5. Electrical activity of the heart
Influenced by nerves (vagus nerve – acetylcholine, epinephrine), hormones, and body temp.
1 - Sinoatrial node (Pacemaker) 2 - Atrioventricular node 3 - Atrioventricular Bundle
(Bundle of His) 4 - Left & Right Bundle branches 5 - Bundle Branches
6 - Purkinje fibers
AV valves
SL valves

6. Pulse 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 bpm
Common pulse points
1. Temporal artery
3. Carotid artery
4. Brachial artery
5. Radial artery

7. Cardiac 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 age
Training heart rate is 75% MHR
e.g = 185 * 0.75 = 139 beats/min
20 minutes, 3x a week

8. Blood vessel structure

9. Physical principles governing blood circulation
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
Nerves, muscle, hormone control

10. Blood 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

14. Blood composition and function

15. Negative feedback mechanism
Erythropoietin produced in liver (low O2) stimulates marrow cells

18. Cardiovascular 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

19. Lymphatic System Functions Anatomy Returns excess body fluid to blood
Transports fats from intestines to blood
Defense
Anatomy
Lymph nodes scattered throughout body (thymus, spleen)
Vessels

20. Check-up Quiz What is ventricular systole?
What makes the “lub dub” sound?
Give one difference between an artery, a capillary, and a vein.
Name one factor that can raise blood pressure.
Name one substance that should be present before a blood clot can form.