Cardiac Cycle 14 Flashcards
What are the three types of plasma proteins?
- Albumins
- Globulins
- Fibrinogen
Albumin
Accounts for 60-80% of PP and smallest; made by liver
- creates colloid osmotic pressure
Globulins
3 types : alpha, beta, and gamma globulin
- Alpha and Beta globulins are made by the liver and transport lipids and fat soluble vitamins.
- Gamma globulins are antibodies produced by lymphocytes
Define anemia
Any condition in which there is an abnormally low [hemoglobin] or RBC
- spencer doesn’t like this definition b/c there is actually plenty of Hb but not enough iron for hemoglobin
Iron-deficiency anemia
Caused by deficiency of iron
Pernicious anemia
Caused by inadequate [vitamin b12], which is needed for RBC production
Aplastic anemia
Due to the destruction of bone marrow
Polycythemia
Abnormal increase in RBC
What is Rh factor ?
It is another type of antigen found on RBC’s
- Rh+ has Rho(D) antigens; Rh- does not
- can cause problems when Rh- mother has Rh+babies
- at birth mother may be exposed to Rh+ blood of fetus
- in later pregnancies mom may produce antibodies against Rh
- in Erythroblastosis fetalis, this happens and antibodies cross placenta causing hemolysis of fetal RBC’s
Hemostasis
Cessation of bleeding that happens in 3 ways:
- Vasoconstriction restricts blood flow to area
- Formation of platelet plug
- Production of web of fibrin proteins
Anticoagulants
Clotting can be prevented by
- Ca++ chelators (things that attatch ca++ to them, so not available for clotting to happen)
- heparin which activates anti thrombin 3
- coumarin blocks clotting by inhibiting activation of vit K
What percent of plasma do plasma proteins constitute?
7-9%
Define Cardiac cycle
repeating pattern of contraction and relaxation of heart.
define end-systolic volume
is amount of blood left in ventricles at the end of systole
define stroke volume
is amount of blood ejected from ventricles during systole
Define end-diastolic volume
is amount of blood left in ventricles at the of diastole
What is isovolumetric contraction?
as the ventricles begin contraction, pressure rises closing the AV valves. This is isovolumetric because all the valves are closed.
What happens when the pressure in the ventricles exceeds that in aorta?
the semilunar valves open and ejection begins and as pressure in the ventricle falls below that in aorta, back pressure closes semilunar valves.
What occurs when the pressure in the ventricles falls below atria?
AV’s open and ventricles fill
how much do the ventricles fill during ventricular diastole?
about 80%
How much does atrial systole send of total ventricular blood into the ventricles
about 20%
What is the first sound of the heart called ?
Lub (1st sound)- produced by closing of AV valves (btw atria and ventricles)
What is the 2nd sound of the heart called?
Dub (2nd sound)- produced by closing of seminars (btw ventricles and aorta or pulmonary artery)
What is a heart murmur?
abnormal sounds produced by abnormal patterns of blood flow in heart. (irregular blood flow)
What can heart murmurs be caused by?
many caused by defective heart valves
- can be of congenital origin
- in rheumatic fever, damage can be from antibodies made in response to strep infection
What occurs in mitral stenosis, 1st stage.
the mitral (A-V) valve becomes thickened and calcified impairing the blood flow from left atrium to left ventricle. this causes accumulation of blood in left ventricle that can lead to pulmonary hypertension
2nd stage of mitral stenosis
- the valves are incompetent when they do not close properly.
- can be damage to papillary muscles
Murmurs caused by septal defects are usually congenital due to…
holes in septum btw left and right sides of heart
-pressure causes blood to pass from left to right.
Are myocardial cells short or long?
They are short, branched and interconnected by gap junctions
the myocardium works in what ?
functional syncytium, because AP’s originating in any cell are transmitted to all others.
-chambers separated by nonconductive tissue.
Ectopic pacemakers
other tissues in heart are spontaneously active but are slower than SA node
-heart beat is way out of range
Myocardial AP’s
myocardial cells have RMP of -90mV; depolarized to threshold by AP’s originating in SA node
Plateau results from what
From balance btw slow Ca++ influx and K+efflux
-repolarization due to opening of extra K+channels
does the AP’s from SA node that spread through the atrial myocardium via gap junction need a special pathway to ventricles ?
yes b/c of non-conducting fibrous tissue
-AV node at base of right atrium and bundle of His conduct AP’s to ventricles.
In the septum of ventricles the bundle of His does what?
divides into right and left bundle branches which gives rise to Purkinje fibers in walls of ventricles; these stimulate contraction of ventricles.
excitation contraction coupling
depolarization of myocardial cells open V-gated Ca++ channels in sarcolemma
-causes opening of V-gated and Ca++ channels release channels in SR(calcium-stimulated-calcium-release)
Calcium-stimulated-calcium-release does what
Ca++ binds to troponin and stimulates contraction (as in skeletal muscle); during depolarization Ca++ pumped out of sarcoplasm and into SR.
Refractory periods contain what
heart contracts as syncytium and thus cannot sustain force; its AP lasts about 250msec
what is an EKG/ECG?
it is a recording of the electrical activity of the heart conducted thru ions in body to surface and recorded by electrodes placed on the skin.
- Note: ECG is not recording of AP!! it is a recording of the electrical activity of the heart!
What are the 3 distinct waves produced during cardiac cycle?
P wave- caused by atrial depolarization
QRS complex- results from ventricular depolarization
T wave- results from ventricular re-polarization
where is the atrial repolarization?
it is hidden by the QRS complex
what are the correlations of ECG with heart sounds
1st sound (lub) comes immediately after QRS wave as AV valves close 2nd heart sound (dub) comes as T wave begins and semilunar valves close.
what is arteriosclerosis?
it is a heart disease that causes the hardening of the arteries. it accounts for 50% of deaths in US, Europe, and Japan.
what happens in arteriosclerosis?
localized plaques (artheromas) reduce flow in an artery and act as sites for thrombus (blood clots)
Is high cholesterol associated with risk of atherosclerosis?
YES
where is cholesterol carried in the blood ?
is carried in blood attached to LDL’s (low density lipoproteins) and HDL’s (high density lipoproteins)
where are HDL and LDL produced?
in the liver and taken into cells by receptor mediated endocytosis
- in blood vessels LDL is oxidized & cause damage.
- liver has receptor for HDL and don’t get oxidized
Arteries have receptors for LDL or HDL?
LDL, only the liver has HDL receptors, which is why HDL is not atherosclerotic
what is ischemia?
a lack of oxygen anywhere in the body
-causes increased lactic acid from anaerobic metabolism.
what is angina pectoris
substernal pain or left shoulder and arm pain
what is a MI?
Myocardial infraction= heart attack
- caused by prolonged (minutes) periods of ischemia resulting in necrosis
- leading cause of death in the world
- diagnosed by high levels of CPK and troponin
define arrhythmias?
they are abnormal heart rhythms which are detectable by changes in EKG
What is tachycardia?
heart rate above 100bpm
what is brachycardia?
heart rate below 60bpm
what is a flutter
coordinated contraction rates can be 200-300/min
fibrillation
contraction of myocardial cells is uncoordinated and pumping ineffective
Ventricular fibrillation is …
LIFE THREATENING
electrical defibrillation does what
resynchronizes heart by depolarizing all cells at same time
what is AV node block
occurs when node is damaged
First degree AV node block is
is when conduction through AV node >0.2 sec
-causes long P-R interval
second degree AV node block is
when only 1 out of 2-4 atrial AP’s can pass to ventricles
-causes P waves with no QRS
third degree or complete AV node block is
no atrial activity passes to ventricles. Ventricles driven slowly by bundle of His or Purkinjes
fibrinogen
- Fibrinogen 4% PP: produced by the liver; serves as a clotting factor, converted to insoluble threads called fibrin during clotting process.
