Heart and Lung Function and Disease Flashcards
Pericardium
-fibrous sac around heart
-Serous layers: Parietal (outer), visceral (on heart and contains fluid within space)
-Innervated by Phrenic Nerve (sensory)
Diastole
-Relaxation
-Filling
Systole
-contraction
-ejection
Afterload
pressure needed to expel blood from the heart
-synonymous with BP
Myocardium
Cardiac muscle fiber
-actin-myosin complex
-Automaticity: contract w/o external stimuli
-Rhythmicity: contract with rhythm
-Conductivity: nerve impulses from one cell to the other due to intercalated discs
-Intercalated disc junctions: Desmosomes (adhesion) and Connexins (conductivity)
Endocardium
-Smooth muscle, innermost layer
Pulmonary Artery
-only artery to carry deoxygenated blood
Pulmonary vein
-only vein to cary oxygenated blood
Right Coronary Artery
-Supplies right ventricle, AV node and SA node
-Right posterior descending
-Right marginal
Left Coronary Artery
-supplies left ventricle, L atrium, septum, SA node
SA Node
-sets heart at pace of >100 without other input
-Susceptible to disease due to pericarditis, occulsion
Sympathetic NS
-increase
-norepinephrine
Inotropic
-strength of contraction
Chronotropic
-speed of contraction
Parasympathetic NS
-decrease
-vagus nerve
-acetylcholine
-60-90 bpm
AV Node
-receive from SA
-to Bundle of His to bundle branches to perkinjie fibers
-40-60 bpm without exernal stimuli
-0.04s to contract Vs
Susceptible to disease due to RCA occlusion
P Wave
atrial depolarization
PR interval
-travel of impulse to Vs
QRS Complex
ventricular depolarization
T Wave
ventricular repolarization
QT Internal
Ventricular systole
Low K
Harder to depolarize, slower heart rate
High K
Easier to depolarize as myocardium is excitable, higher heart rate
Cardiac Output
-CO= HR x SV
-5-6L at rest, can increased 4-7x with exercise
-Effects systolic BP
Blood Pressure
BP=HR x SV x Total peripheral Resistance
TPR affects diastolic BP
Mean Arterial Blood Pressure
-average pressure in the systemic system
MAP= DBP + 1/3 (SBP-DBP)
-Normal: 93 mmHg
-assess peripheral functions of CV
-cautions <60mmHg
Determined By:
-BV, CO, Peripheral resistance, distribution of blood in veins
Pulse Pressure
SBP-DBP, difference
Effect of Posture on BP
Standing: lower BP, blood pools in legs
Laying: blood evenly in veins, higher BP
BP Normal
<120/<80
BP Elevated
120-129/<80
High BP Stage 1
130-139/80-89
High BP Stage 2
> 140/>90
Hypertensive Crisis
> 180/>120
HR
-Beats per minute
Affected by: Baroreceptors, ANS, endocrine, integrity of the system, temperature, emotions
SV
-amount of blood pumped out each beat
-Afterload-Preload, heart contractility
-increases 40-60% during exercise
Cardiac Preload
-End diastolic volume: amount of left ventricular blood volume prior to contraction
Dependent on:
-venous return, BV, LA contraction, Starling law
Cardiac Afterload
-Amount of resistance encountered by left ventricle
Myocardial Contractility
-neural and hormonal influences
Ejection Fraction
Ejection Fraction= SV/EDV
-55-70%
-Low EF indicates systolic heart failure
-EF can be preserved with overall decrease in BV, weak heart increases backflow that increased SV
Hypoxia
O2 concentration of tissues
Hypoxemia
O2 concentration of blood
ESV
End Systolic volume: volume of blood in a ventricle at the end of a contraction
Right Shift in O2 Concentration
-reduced affinity for for O2, higher po2 will result in lower hemoglobin concentrations
-high temp, high acidity
Left Shift in O2 concentration
-increased affinity for O2, lower po2 will result in higher hemoglobin concentrations
-low temp, basic environment
Fick equation
-VO2= HR x SV x (a-vO2 diff)
a-vO2 Diff
-difference in O2 between arteriole and venule
CO Distribution
Muscles: 10-15% (80-85% with exercise)
Trunk: 20-30%
Brain and heart: 5%
Oxygen Extraction
-tissues utilize the same relative amount of o2 in relation to blood o2
Pulmonary O2 Exchange Factors
-Area of capillary membrane
-Diffusion capacity of alveoli
-Pulmonary Capillary volume
-Ventilation to perfusion ratio
Area of Capillary Membrane
invaginations increase the surface area
Diffusion capacity of alveoli
-changes in surface area
-changes in membrane
-gas uptake issues
Pulmonary capillary volume
-increases with exercise
Ventilation to Perfusion Ratio (V/Q)
-blood flow to alveoli must match ventilation or =hypoxemia
-changes with posture
-Norm: 0.8
Reduced: decreased ventilation to perfusion, blood shunted to other parts of the lung, vasoconstriction at arterioles to reduce BV, corrected with O2
Increased: increased ventilation to perfusion, vasodilation to increase BV, dead space
Arteriole Vasoconstriction
-alpha receptors
Shunt blood to muscles, from skin and mesenteric
Arteriole Vasodilation
-induced by increased vessel stretch
-induced by low O2 or high H+, CO2, metabolites
Beta Receptors
-increased blood flow to Skeletal muscle
-increase ventilation and alveolar perfusion
Cardiac Muscle Dysfunction
-most common cause of Congestive Heart Failure
Symptoms:
-dyspnea
-fluid buildup
-fatigue at rest
Most common cause of pulmonary congestion
-heart failure
-mostly right side affected
Causes of Cardiac Muscle Disease: Hypertension
Increased BP
-increased workload w/o increased blood supply
-decreased BV
-hypertrophy of myocardium that cannot relax well
-BV damage
Causes of Cardiac Muscle Disease: Coronary Artery Disease
-2nd most common cause of CMD
-supply and demand issue
-lipid deposits: atherosclerosis
-scar formation: decreases contractility
Causes of Cardiac Muscle Disease: Myocardial Infarction
-irreversible myocardial necrosis
-most commonly affects left ventricle
PT
-Increased Troponin, CK-MB that needs to come down
-ST elevation on ECG “Stimmy”
Causes of Cardiac Muscle Disease: Cardiac Arrhythmias
-abnormal rate of contractions
-can cause sudden cardiac arrest from SA node
-can lead to decreased CO
-Sick Sinus node syndrome
-Suprasventricular tachycardia
-V fib
Lab Values: Sodium
Increased
-dehydration
Decreased
-overhydration
Lab Values: Potassium
Increased
-Renal retention, decreased insulin
Decreased
-Excess renal secretion, aldosterone, burns
Lab Values: Calcium
Increased:
-hyperparathyroidism, hyperthyroidism
Decreased: hypoparathyroidism, renal failure
Causes of Cardiac Muscle Disease: Renal Insufficiency
-contributes to CMD due to increased fluid triggered by low BP or low BV
-RAAS
-maintains Na and K balance
Causes of Cardiac Muscle Disease: Cardiomyopathy
-disease of heart muscle leading to heart failure
-impaired contractility
-HTN, MI, metabolic disorders, heart valve issues
Causes of Cardiac Muscle Disease: Dilated Cardiomyopathy
Heart failure with reduced ejection fraction (<40)
-systolic dysfunction: less effective pump
-mitochondrial dysfunction
-increased LV EDV
-lead to electrical issues
Causes of Cardiac Muscle Disease: Hypertrophic Cardiomyopathy
-enlarged heart that cannot relax
-diastolic dysfunction: less compliant
-increases left EDP
-Heart failure with preserved EF
-rapid ventricular emptying
-muscle cells disorganized
-common cause for sudden cardiac arrest in young athletes
Causes of Cardiac Muscle Disease: Restrictive Cardiomyopathy
-cannot relax
-EF preserved
-diastolic dysfunction
-scar tissue (sarcoidosis/radiation) OR defect in myocardial relaxation
-hypertrophy
Heart Valve Abnormalities
-contracts more forcefully
-induces myocardial hypertrophy
-deceases ventricular distensibility
-decreases CO and BP
Pericardial Effusion
-buildup of fluid compress the heart
Cardiac Tamponade
-pressure on heart leads to decreased heart function
-worse when lying down
-relieved when standing
Pulmonary Embolism
-lung infarction due to decreased BV
-increased pulmonary hypertension
-increases load to right side of heart
-presence of ascities, bilateral LE edema and jugular vein distension
-increases V/Q ratio
Pulmonary Hypertension
-risk for cardiac disease
->20mmHg
-increased R ventricle work (Swangan’s Catheter)
Heart Disease Vitals
-pO2: hypoxia (92-96%)
-RR: tachypnea
-HR: tachycardia
-BP: orthostatic hypotension
Congestive Heart Failure
-decreased CO
-LV failure
-increased BNP (stretch protein in heart)
-attempts compensatory strategies (sympathetic, RAAS, heart receptors, EPO)
Pulmonary System and CHF
-pulmonary edema
-decreased o2 concentration
Skeletal Muscle Function and CHF
-decreased type 1 fibers
-less contraction strength
Pancreas and CHF
-impairs blood flow
-impairs insulin release
Hematologic function and BHF
-polycythemia (thick blood)
-thrombocytopenia (low platelets)
Anemia
-can cause CHF
-can harm or help
-shifts curve to right; more o2 needed
Neurohumoral Function and CHF
-SNS overstimulation and downreg of B1 receptors
B1: myocardial inotrophy and chronotrophy
B2: vasodilation and bronchodilation
a1: vasoconstriction
a2: arterial vasodilation (constriction of coronary)
Renal Function and CHF
-RAAS
-a receptor activity
-decreased renal activity
MAP
-mean arterial pressure
-total pressure of the system
Pulse Pressure
-how hard the heart is working
40-60
Rate Pressure Product
SBP*HR
-cardiac function
