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PHGY 210 Study Guide - Final Guide: Perfusion, Palpation, Qrs Complex


Department
Physiology
Course Code
PHGY 210
Professor
Ann Wechsler
Study Guide
Final

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Phgy 210 Cardiovascular Physiology
Functions of the Cardiovascular System
Bringing nutrients into the body (e.g. from intestine to liver)
Bringing fuel to cells (e.g. glucose from liver to brain)
Bringing O2 to cells from lungs
Removal of waste products (e.g. CO2 to lungs: ammonia to liver urea kidneys)
Circulation of hormones (e.g. adrenaline from adrenal glands to skeletal muscles)
Circulation of immune cells and antibodies
Regulation of electrolytes Na+, K+, Cl-
Regulation of pH (lungs, kidney)
H2O balance (e.g. exercise: over-hydration)
Thermoregulation (e.g. exercise, hypothermia)
Diffusion: The spontaneous movement of particles caused by random thermal motion
Small organisms don’t need a cardiovascular system
Concentration gradients drive O2 and CO2 transport
Oxygen goes into the alveolus by diffusion: convective or bulk flow
Pressure in the lungs sucks in a bunch of air
Diffusion Fick’s Law
Flux = flow per unit area = D x concentration gradient where D = diffusion coefficient
Flux = D x (𝐶𝑜𝑢𝑡−𝐶𝑖𝑛
𝑑)
Flow = flux x area = D x (𝐶𝑜𝑢𝑡−𝐶𝑖𝑛
𝑑) x A
Pump: Heart
Pipes: Vessels
Fluid: Blood
Kardia: heart
Vas: Vessel
Insect Circulation
Open circulation
Circulation through ostium
Piscine Circulation
Ventricle pumps blood out to the gills
Oxygen is added to the blood and CO2 is taken out
Oxygen is then used up and sent back to the atrium through the vein
Closed, single-loop circulation with 2 chambers

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Amphibian & Reptilian Circulation
Systemic and pulmocutaneous circuit (lung and skin)
One ventricle, two atriums (3 chambers)
Closed, double-loop circulation
Amphibians can breathe through their skin to some extent
Both atria contract at the same time to deliver oxygenated and de-oxygenated blood into the ventricle at the same
time
Avian and Mammalian Circulations
Interventricular septum that separates the ventricles
o Makes sure that the oxygenated and de-oxygenated blood stay separated
Blood is always within the vessels or the heart itself
Right ventricle pumps blood to the lungs
Left atrium receives oxygenated blood, pumps it into the left ventricle which pumps it into the rest of body
Haemodynamics
“the branch of physiology dealing with the forces involved in the circulation of the blood”
“the circulation and movement of blood in the body, and the forces involved therein”
Volume
o 60% of the blood is in the veins or the venules
o 10% of the blood is in the arteries
o Venous system: capacitance
o Arterial system: resistance
o Blood volume = 5 L, 1 unit of blood = 450 mL
Flow
o Rate of change in fluid
Flow = area x velocity
Units: cm3/sec
Flow = volume/time
Units: mL/min
o Left and right ventricle pumps at 5000 mL/min
o Arterial and venous pressure is the same
o Right heart is in series with the lungs
o The biggest flow is from the skeletal muscle
o Velocity in the capillaries must be slow so there is time for gas exchange to occur
o Capillaries need a high total cross sectional area to provide enough surface for gas exchange to occur
Pressure
o Pressure = Force/Area
o Units: pascal (Pa) = Newton/m2
o Work done on system to pressurize it, so “pressure energy” stored in system
o Longitudinal pressure gradient will generate a flow
o Hydrostatic pressure
The pressure exerted by a fluid at equilibrium at a given point within the fluid, due to the force of gravity
V = area x height = Ah

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M = density x volume = ρV = ρAh
F = mass x gravity = mg = ρAhg
P = force per unit area = F/A = ρgh
1 cm H2O = 0.98 kPa
o Atmospheric pressure
o Stephen Hales
Took a hollow glass tube and stuck it into carotid artery of a horse to test the pressure
Hydrostatic pressure acting downwards in the tube as the blood acts upwards
Found that the blood rose 280 cm = 200 mmHg
o Mercury sphygmomanometer
Column of mercury
1 mmHg = 14 mm H2O = 1.4 cm H2O = 0.13 kPa
o Perfusion pressure
Perfusion pressure = inlet pressure outlet pressure = arterial pressure venous pressure
P = Pin Pout = Pa Pv
Normally, Pa >> Pv (100 mmHg vs. 5 mmHg)
No perfusion pressure no flow
Pin = Pout ∆P = 0
Resistance
o Resistance = perfusion pressure / flow
o Laminar or parabolic flow
Frictional losses in a viscous flow: generation of heat loss of pressure
o Poiseuille’s law
Flow = ∆P/R
o Control of vessel resistance
R is proportional to 1/r4 where r = radius
o Resistances in series
R = R1 + R2
o Resistances in parallel
1/R = 1/R1 + 1/R2
The Heart
The Four Chambers of the Heart
Left and right atrium + left and right ventricle
2 hearts = left and right
The Great Vessels
Left ventricle is part of the systemic system
Right ventricle blood leaves through the pulmonary trunk which divides into two arteries for both lungs
Deoxygenated blood goes into the right atrium through the superior and inferior vena cava
Blood from the lungs comes into the left atrium through the pulmonary veins
Vertical Cross-Section through the Heart
Posterior wall of the right atrium can be seen
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