Download Cardiovascular System: Physiology

Questions from Tuesday
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granules function similar to lysosomes
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contain proteins/enzymes that kill ingested bacteria,
fungi, viruses
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responsible for the green color of pus
histamines and MS
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myeloid vs. myelin
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blocking certain histamine receptors reduced
symptoms of MS-like disease in mice
myelos- Greek for marrow
RBCs do not have DNA, do have RNA
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negative feedback
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feedback causes the stimulus to decline
calcitonin and PTH each are a feedback system,
the hormones have antagonistic effects
questions 34, 45, 62a, 62c
Chapter 11:
Heart Physiology
Heart Dysfunctions
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pericarditis - inflammation of pericardium
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incompetent valve - does not close properly
valvular stenosis - valve stiffening due to bacterial
infection
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decrease in amount of serous fluid in pericardial cavity
both cause increased workload in heart
angina pectoris - myocardium deprived of O2
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if prolonged, ischemic heart cells die = infarct
myocardial infarction or heart attack
Cardiac Muscle
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cardiac muscle can contract spontaneously &
independently
needs control system to regulate
Heart Activity
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regulation by two systems:
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intrinsic conduction system (nodal system)
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sets basic rhythm
neural controls (ANS)
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increase or decrease heart rate
Nodal System
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special nervous/muscle tissue
causes one way heart muscle depolarization:
atria to ventricles
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contraction rate of 75 bpm
sinoatrial node
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most important
right atrium
Nodal System
Sinoatrial node
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highest rate of depolarization
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pacemaker
SA node -> atria -> pause* -> AV node ->
bundle branches -> Purkinje fibers
*lets the atria contract before the ventricles
Heart Rate Dysfunctions
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damage to the SA node = slower heart rate
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ischemia (inadequate blood supply) of the myocardium
can lead to fibrillation
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artificial pacemaker
uncoordinated contractions
defibrillator - depolarizes heart to let natural pacemaker to
reestablish normal rhythm
tachycardia-rapid heart beat (>100 bpm)
bradycardia-slow heart beat (< 60 bpm)
Cardiac Cycle
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systole - contraction of ventricles
diastole - relaxation of ventricles
cycle = 1 complete heartbeat
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mid-to-late diastole
ventricular systole
early diastole
Cardiac Cycle
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mid-to-late diastole
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complete relaxation
low pressure = passive blood flow
at end, atria contract
which valves open?
which valves closed?
Cardiac Cycle
Cardiac Cycle
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ventricular systole
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ventricles contract
increased pressure
atria are relaxed
which valves open & closed?
Cardiac Cycle
Cardiac Cycle
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early diastole
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ventricles relax
atria filling with blood
which valves open & closed?
Cardiac Cycle
Cardiac Cycle
Heart Sounds
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“lub dup…lub dup…lub dup…”
sounds come from what?
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lub = closing of AV valves
dup = semilunar valves close at end of systole
heart murmur - valve problems
Cardiac Output
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CO = amount of blood pumped out by each
ventricle in one minute
CO = heart rate (HR) X stroke volume (SV)
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SV = volume of blood pumped by each
ventricle each beat
What is CO if HR is 75 bpm and SV is
70 ml/beat
=5250 ml/min
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Regulation of Stroke Volume
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how much cardiac muscle cells are stretched
before contraction
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stretch relies on venous return
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more stretch = stronger contraction
amount of blood distending the ventricles
increase in volume or speed of venous return
also increases stroke volume
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get up and jog in place for 1 minute
Basic Heart Rate (HR)
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control of heart rate by ANS
sympathetic can increase HR
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parasympathetic slow and steady HR
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more O2 and glucose available to cells
vagus nerve
epinephrine & thyroxine increase HR
ion excess or deficit (Ca2+, Na+, K+) can change
heart activity
Basic Heart Rate
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epinephrine & thyroxine increase HR
ion excess or deficit (Ca2+, Na+, K+) can change
heart activity
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age, gender, exercise, body temp
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Heart Dysfunctions
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congestive heart failure - heart cannot meet
tissue circulation needs
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coronary artherosclerosis
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clogging of coronary arteries
high bp
Blood Vessels: General functions
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moves blood, plasma
transports hormones, nutrients, gases
helps the transport of lipids
Blood Vessels
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arteries - move blood away from the heart
capillary beds - gas exchange occurs
veins - return blood to heart
Blood Vessels
• tunica intima
• tunica media - smooth muscle & elastic tissue
• tunica externa - fibrous connective tissue
Arteries vs. Veins
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artery walls thicker than veins
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tunica media is heavier
close to heart
arteries must expand and recoil so walls are strong
and stretchy
Arteries vs. Veins
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veins
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muscular pump
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far from heart
low pressure
valves
contraction
respiratory pump
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inhale = drop in thoracic pressure
Capillaries
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walls one cell layer thick
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only tunica intima
gas exchange
networks are called beds
vascular shunt
true capillaries
Capillaries
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precapillary sphincter
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acts as valve
regulates blood flow
Cardiovascular Physiology
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arterial pulse
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from what?
blood pressure
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higher closer or further away from heart?
keeps blood circulating continuously
Blood Pressure
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highest in large arteries
lowest in venae cavae
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muscular pump & respiratory
pump are important for
venous return
what happens if you cut a
vein? an artery?
Blood Pressure
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elastic artery walls help keep continuous blood
flow
arteriosclerosis = hardening of artery walls
can lead to hypertension, or high blood
pressure
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why?
Measuring Blood Pressure
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rises & falls each beat
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systolic: pressure at ventricular contraction
diastolic: pressure at ventricular relaxation
auscultatory method
Blood Pressure
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remember CO = HR X SV
blood pressure, BP = CO X PR
PR is peripheral resistance = amount of friction
blood encounters in the vessels
any changes in CO or PR affects BP
Blood Pressure
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sympathetic nervous system
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kidneys
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cold = constrict
heat = dilate
chemicals
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alter blood volume in response to blood pressure
temperature
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vasoconstriction: narrowing of vessels
epinephrine
alcohol
diet
Blood Pressure
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110-140 mmHg systole / 75-80 mmHg diastole
hypotension = BP <100 mmHg systolic
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physical conditioning
chronic - poor nutrition, low blood proteins
orthostatic hypotension - dizziness upon rising
in the elderly
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aging sympathetic nervous system reacts slowly to
postural change
Blood Pressure
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hypertension - 140/90 mmHg sustained
strains heart, damages arteries
diet, obesity, heredity, race, stress
Capillary Exchange
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capillaries deliver gases and nutrients to all
body cells
how do substances move with respect to their
concentration?
oxygen and nutrients
carbon dioxide, other wastes
Capillary Exchange
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Four routes from endothelial cells of capillary
wall to interstitial fluid
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diffuse directly across plasma membranes
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what kind of substances can do this?
endocytosis or exocytosis
Capillary Exchange
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intercellular clefts
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gap in plasma membrane
all cells BUT brain cells
fenestrated capillaries - (fenestra = window)
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free passage of small solutes and fluids
absorption or filtration is important
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intestines, endocrine glands, kidneys
Capillary Fluid Transport
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leaky clefts and fenestrations
blood pressure forces fluid outward
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arterial end of cap bed
osmotic pressure draws fluid back in
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blood vs. interstitial fluid
venous end of cap bed
Capillary Fluid Transport
Lab
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Ex. 21 - All activities
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Ex. 22 - Activities 1-4
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vein, artery, capillary slide on a microscope up front
if time Act. 5-6
Turn in on Tuesday:
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Review sheets 21 & 22 on pp. 327-338
Ex. 22 pp 195-197
Ex. 22 pp 198-200, if time