1. Physiology of Circulation
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2. What is Arterial Pulse?
Alternating expansion and recoil of a blood vessel wall (the pressure wave) that occurs as the heart beats
Locate arterial pulse at “pressure points” in superficial arteries
These same points are used to stop blood flow due to hemorrhage from injury
Avg is bpm at rest for a healthy person
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3. Figure 11.19 Body sites where the pulse is most easily palpated.
Superficial temporal artery
Facial artery
Common carotid artery
Brachial artery
Radial artery
Femoral artery
Popliteal artery
Posterior tibial
artery
Dorsalis pedis artery

4. Blood Pressure & the BP gradient:
Blood pressure is: the pressure the blood exerts against the inner walls of the blood vessels
Blood is forced along a descending pressure gradient
Pressure is highest in the large systemic arteries, lower in the capillaries, and lowest in the veins
Elasticity of vessels is pertinent to healthy, elastic arteries
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5. Measuring Blood Pressure
Systolic—pressure at the peak of ventricular contraction
Diastolic—pressure when ventricles relax
Expressed as systolic over diastolic
120/80 mm Hg is average
The brachial artery is used for measurement
Hypotension- low blood pressure (<100 sys.)
Hypertension- high blood pressure (>140/90)
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6. Factors that affect Blood Pressure
Resistance within blood vessels (increases)
Kidneys regulate blood volume via enzymes
Temperature-
cold causes vasoconstriction
Heat causes vasodilation
Chemicals
Hormones like epinephrine
Drugs/nicotine
Diet
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7. Capillary Exchange of Gases & Nutrients
Gas and nutrient exchange occurs through capillary walls
Driven by concentration gradients
Oxygen and nutrients go from blood to tissues
Carbon dioxide and other wastes go from tissue to blood
Substances diffuse through the interstitial fluid (tissue fluid) found between cells
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8. Methods of exchange: TRANSPORT
Direct diffusion through membranes
Diffusion through intercellular clefts/gaps
Diffusion through pores
Transport via vesicles (bulk transport)
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9. Figure 11.23 Capillary transport mechanisms.
Lumen of
capillary
Vesicles
pore
Intercellular
cleft
Transport
via vesicles 4 3
Diffusion
through pore
Diffusion through
intercellular cleft/gap 2
Direct
diffusion
through
membrane 1
Interstitial fluid

10. The force of pressure in capillary beds
Blood pressure forces fluid and solutes out of capillaries at the arterial end
Osmotic pressure draws fluid into capillaries at the venous end
At the arterial end, BP > OP
At the venous end, BP < OP
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11. Tissue cell Interstitial fluid
Figure Bulk fluid flows across capillary walls depend largely on the difference between the blood pressure and the osmotic pressure at different regions of the capillary bed.
Tissue cell
Interstitial fluid
Net fluid
movement
out
Net fluid
movement in
Arterial
end of
capillary
Venule
end of
capillary
At the arterial end of
a capillary, blood
pressure is more than
osmotic pressure,
and fluid flows out of
the capillary and into
the interstitial fluid.
At the venule end of
the capillary, blood
pressure is less than
osmotic pressure,
and fluid flows from
the interstitial fluid
into the capillary.
Blood pressure is
higher than osmotic
pressure
Osmotic pressure
remains steady
in capillary bed
Blood pressure is
lower than osmotic
pressure