Human Circulation

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Human Circulation

• A closer look

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Contents

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

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Cardiac cycle complete sequence of pumping and
filling
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Electrical activity of the heart

• EKG or ECG (electrocardiogram)
• P wave - spread of electrical activity over the
  atria, beginning of its contraction
• QRS complex - spread of electrical activity over
  the ventricles, beginning of its contraction
• T wave - recovery phase of the ventricles

1 - Sinoatrial node (Pacemaker)2 -
Atrioventricular node3 - Atrioventricular Bundle
(Bundle of His)4 - Left Right Bundle
branches5 - Bundle Branches 6 - Purkinje fibers
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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
• Average adult
• CO 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. 200-15 185 0.75 139 beats/min
20 minutes, 3x a week
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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 60-100 bpm
• Common pulse points
• 1. Temporal artery
• 3. Carotid artery
• 4. Brachial artery
• 5. Radial artery

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Blood vessel structure
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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 pipes
  delivering the fluid
• Slows down in capillary beds

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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

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Blood composition and function
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(No Transcript)
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Lymphatic System

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

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Cardiovascular disease

• Cardiovascular disease (gt50 of all deaths)
• Heart attack- death of cardiac tissue due to
  coronary blockage
• Stroke- death of nervous tissue in brain due to
  arterial blockage
• Atherosclerosis arterial plaques deposit
• Arteriosclerosis plaque hardening by calcium
  deposits
• Hypertension high blood pressure
• Hypercholesterolemia LDL, HDL

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Quiz Modified true or false

1. Water moves from a region of lower solute
   concentration to a region of higher solute
   concentration through osmosis.
2. Vacuoles bud off the rough ER and transport
   proteins to the receiving end of the Golgi
   apparatus for further modification.
3. The sandwich model is currently the accepted
   model for the plasma membrane.

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Quiz Modified true or false

1. The planaria has an open circulatory system.
2. In insects, oxygen is not transported using the
   circulatory system.
3. Interstitial fluid and blood are separate in an
   earthworm.
4. One disadvantage of amphibian circulation is that
   some mixing occurs in the heart.

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Quiz Modified true or false

• Turtles are the only reptiles with four-chambered
  hearts.
• During atrial systole, the atrioventricular
  valves are closed.
• The T wave in an ECG corresponds to ventricular
  diastole.
• The stretching of arteries in response to
  heartbeat is called the cardiac output.

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Quiz Modified true or false

• Valves and skeletal muscle contraction facilitate
  blood flow in veins.
• Capillaries have the highest total
  cross-sectional area of the three types of
  vessels.
• Blood pressure is equal to osmotic pressure at
  the arterial end of the capillary.
• When the precapillary sphincters are relaxed,
  blood flows through the capillary beds.