Clinical Chemistry

Pericardium
Double-walled sac that surrounds heart with a serous membrane between layers
Epicardium
outer layer of the heart
Myocardium
middle layer, cardiac muscle, pumps blood
Endocardium
inner layer; forms valves
Atrioventricular Valves
between atria and ventricles
semi-lunar valves
between ventricles and corresponding arteries
Sinoatrial node
pacemaker; iniates contractions and located in the right atrium; generates impulses at a basic rate of 70 bpm
QRS
Ventricular depolarization, contraction
P
atrial depolarization
T
ventricular repolarization
Thick Filaments
Myosin
Thin filaments
actin
Anisotropic (A) band
contains both actin and myosin
Isotropic (I) band
contains only actin
Z band
attachment of actin and associated proteins
Myosin
Large filamentous molecule composed of 6 peptide chains 2 heavy chains and 4 light chains
Actin
Long filaments polymers of 2 strands of globular monomers
Cardiac Specific troponins
Troponin T cTnT and Troponin I cTnI
Congestive Heart Failure
Characterized by edema in the lungs, rest of body; caused by coronary artery disease, cardiomyopathies, myocarditis, valvular disease, cardiac arrhythmias
Uremia
an increase in blood urea
Azotemia
an increase in N2-containing endproducts including urea, creatinine and uric acid
Brain Natriuretic Peptide (BNP)
Released in response to ventricle volume expansion and pressure overload, approved for diagnosis of CHF
Chronic Heart Disease Risk Factors
Hypertension, Sedentary lifestyle, response to stress, diabetes mellitus, hyperlipidemia.
Consequences of ischemia
CHF
Angina pectoris
Myocardial Infarction (MI=heart attack)
Diagnosis of Myocardial Infarction
Patient history, serum markers, EKG Changes (need 2 out of 3 to make diagnosis)
CK-1 (CK-BB)
Predominantly in brain; closest to the cathode in electrophoresis
CK-2 (CK-MB)
Relatively specific to heart; in between CK 1-3 for electrophoresis
CK-3 (CK-MM)
Cardiac and skeletal muscle; stays by the anode in electrophoresis
Myoglobin (Cardiac marker)
Found in skeletal and cardiac muscle.
Rapidly released upon muscle damage
After MI increases 2-4 hours and peaks at 6 hours.
Lipid
Hydrophobic, non-polar organic molecules
Diverse structure and function including:
cell membrane components, bile acids, steroid hormones, surfactants, vitamins, energy source
Tangier Disease
Caused by increased catabolism of HDL
Defect in catabolism on Apo A-I
Homozygotes may have increased risk of CHD
Heterozygotes exhibit no clinical manifestations
Plasma Appearance
Creamy layer on top indicates
increased chylomicrons (need a fasting sample which this is not)
Plasma appearance is Lipemic (turbid of milky throughout)
increased VLDL, IDL
Plasma appearance is no turbity, slight orange color
increased LDL
Plasma appearance is Normal, Clear
Increased HDL
Atherogenic Lipoproteins
LDL, IDL, Lp(a), Chylomicrons, VLDL, Chylomicron remnants
The majority of the plasma cholesterol is transported by which lipoprotein?
LDL
High levels of which lipoprotein class are associated with a decrease risk of accelerated atherosclerosis?
HDL
Important functions of cholesterol
Formation of bile acids
Structural component of cell membranes
precursors of steroid hormones
ApoB100
the apoprotein that contributes to the atherogenic properties of LDL particles