A & P 208 Test 2-6
cardiac tamponade
1. accumulation of large amounts of fluid or blood in the pericardial cavity which compresses the heart from outside 2. this limits the expansion of the heart and consequently it cannot adequate fill during relaxation. Therefore, the heart does not pump and creates a lethal stimulation for the person 3. this may be caused by a rupture of the heart wall subsequent to a heart attack, ruptured blood vessel in the pericardium after the removal of a tumor, damage following radiation therapy, or trauma to the chest
pH, CO2 and O2
1. chemoreceptors reflexes assist in regulation of heart activity through monitoring of pH and blood gases 2. with a drop in pH and rise in CO2, there is an increase in sympathetic stimulation and a decrease in parasympathetic stimulation. This results in increased heart rate and force of contraction. a. the increase in cardiac output allows for a greater amount of blood to flow through the lungs so the CO2 can be eliminated b. the decrease in Co2 helps to raise the blood pH
3 uncontrollable factors
1. diabetes mellitus 2. genetic predisposition 3. male gender after age 60 the risk is equal for both sexes
angina pectoris
1. heart pain, or pain in the chest 2. results from ischemia of the cardiac muscle
5 risk factors in heart disease
1. high blood cholesterol level 2. high blood pressure 3. cigarette smoking 4. obesity 5. the uncontrollable factors
effects of body temperature
1. small increases in cardiac muscle temperature result in the heart rate accelerating 2. decreases in temperature cause the heart rate to slow
extracellular Ion concentration
1. the major ions which affect the cardiac muscle are K+, Na+ and Ca2+ 2. excess K+ will cause the heart rate and stroke volume to decrease a. if the K+ increases by two times the normal amount the result is heart block b. the excess K+ can lead to ectopic action potentials and if enough ectopic action potentials are produced fibrillation results. 3. a reduction in extracellular K+ may cause the resting membrane potential to become hyperpolarized. a. this results in longer time for the membrane to depolarize b. the ultimate result is a decrease in heart rate 4. elevated Ca2+ produces greater force of cardiac contraction a. the reason is from a higher influx of Ca2+ in the sarcoplasm b. elevated levels have an indirect effect on heart rate since they reduce the frequency of action potentials c. overall a Ca2+ increase results in lower heart rate 5. low Ca2+ levels increase heart rate, but not noticeable until the level has fallen to 1/10 of the normal level
high blood cholesterol level
HDL- high density lipoprotein- removes cholesterol from circulation LDL- low density lipoprotein- associated with fatty plaque formation VLDL- very low density lipoprotein; contributes to increased fatty plaque formation a. desirable levels * total triglyceride should be less than 200mg/dL * HDL should be greater than 40mg/dL * LDL should be less than 130mg/dL b. low fat diet c. exercise- increases hearts demand for oxygen (benefits from aerobic exercise) * increased cardiac output * increased HDL and lower TC (total cholesterol) * better lung functions * decreased BP * weight loss
obesity
a. development of extra capillaries in adipose tissue b. estimate of 300km or 200 miles of blood vessels for each pound of fat. c. heart has to work harder to pump blood
cigarette smoking
a. nicotine is a vasocontsrictor which increases blood pressure b. stimulates adrenal glands to release NE and epinephrine c. heart rate along with blood pressure are increased
myocardial infarction (MI)
aka heart attack 1. this is death of heart muscle from lack of oxygen 2. the muscle is replaced with scar tissue, which is non-contractile tissue
high blood pressure
can be reduce by exercise, diet and medication
pericarditis
extremely painful 1. inflammation of the pericardium 2. may result from infection, diseases of the connective tissue, or damage from chemotherapy and radiation treatments
lack of regular exercise
risk factor for heart disease
