Cardiovascular system Flashcards
What 3 factors regulate Cardiac Stroke Volume
- The degree of stretch in the heart before it contracts
- The forcefulness of contraction of individual ventricular muscle fibres
- The pressure required to eject blood from the ventricles
What is the inflammation of the endocardium typically involving the heart valves? [Mostly caused by bacteria]
[Bacterial] Endocarditis
What is myocarditis
Inflammation of the myocardium that usually occurs as a complication of a viral infection, rheumatic fever or exposure to radiation or certain chemicals or medications
Medical term for Heart Enlargement?
Cardiomegaly
What is Cardiac Catheterization
A procedure used to visualise the heart’s coronary arteries, chambers, valves and great vessels.
What is the medical term meaning cessation of an effective heartbeat
Cardiac Arrest
What is the medical term describing failure of the myocardium to contract
Asystole
Name the X-ray examination of the heart and great blood vessels after injection of a radiopaque dye into the bloodstream
Angiocardiography
List some types of arrythymias
SVT - Supraventricular Tachycardia Heart Block APC - Atrial Premature Contraction AF - Atrial Fibrillation VPC - Ventricular Premature Contraction VT/Vtach - Ventricular Tachycardia VF Ventricular Fibrillation
What does arrhythmia or dysrhythmia refer to?
An abnormal rhythm as a result in the conduction system of the heart. The heart may beat too fast or too slow.
What does PDA stand for and what is it?
Patent Ductus Arteriosus - A congenital heart defect
What are the treatments for myocardial infarction
Injection of a thrombolytic (Clot dissolving) agent e.g. streptokinase or tpa, plus heparin (anti-coagulant) OR Performing coronary angioplasty OR Coronary artery bypass grafting
What might happen if the size and location of an infarcted area of heart tissue is significant?
It may disrupt the conducting system of the heart and cause sudden death by triggering ventricular fibrillation
What happens to the heart tissue distal to an obstructed artery?
The tissue dies and is replaced by non-contractile scar tissue and consequently the heart loses some of its strength
What does infarction mean?
The death of an area of tissue because of interrupted blood supply
What might occur as a result of an obstruction to blood flow in a coronary artery?
Myocardial Infarction
Which areas of the body is the pain in angina pectoris referred to (in many instances)?
Neck
Chin
Down the left arm to the elbow
What is Angina Pectoris and what condition of the heart does it usually accompany?
It literally means “strangled chest” and is a severe pain. It often accompanies myocardial ischemia
What is Myocardial Ischemia
The medical term for a condition of reduced blood flow to the myocardium.
What drugs are used to treat coronary artery disease?
Anti-hypertensive drugs Nitroglycerin Betablockers Cholesterol lowering agents Clot dissolving agents (thrombolytic)
How are smooth muscle fibres involved in forming an atherosclerotic plaque?
They form a cap on top of the fatty streak formed by the foamy macrophages and T-cells
How is it that despite the formation of atherosclerotic plaques in the arteries, blood can flow through the affected arteries with relative ease sometimes for decades?
Atherosclerotic plaques expand away from the bloodstream rather than into it.
What is the difference in LDL and HDL? Which type is better for our health?
LDL - Transports cholesterol from liver to body cells for use in cell membrane repair and production of steroid hormones and bile salts
HDL - Removes excess cholesterol from body cells and transports it to the liver for elimination.
High levels of LDLs are associated with higher risk of CAD.
Why are high levels of LDL considered bad for our health?
They are associated with a increased risk of Coronary Artery Disease due to their promotion of atherosclerosis. They are often referred to as bad cholesterol.
Name two major lipo proteins
LDL - Low density Lipo proteins
HDL - High density Lipo proteins
Describe the structure of a lipo protein including where in the body they are made.
Manufactured by the liver and small intestine.
Spherical particle
Inner core of triglycerides and other lipids
Outer shell of proteins, phospholipids and cholesterol
What 3 substances make up an atherosclerotic plaque?
1) Fatty substances
2) Cholesterol
3) Smooth muscle fibres
How does Homocysteine possibly increase the likelihood of coronary artery disease?
It’s an amino acid that may induce blood vessel damage by promoting platelet aggregation and smooth muscle fibre proliferation
How does fibrinogen increase the risk of Coronary Artery Disease?
May help regulate cellular proliferation, vasoconstriction and platelet aggregation.
What is a Lipoprotein? (In relation to CAD)
LDL like particle
Binds to endothelial cells, macrophages and blood platelets
May promote proliferation of smooth muscle fibres
Inhibits breakdown of blood clots
What are C-reactive proteins?
Produced by Liver and maybe present in the blood in inactive form
Converted to an active form during inflammation
May play a direct role in development of atherosclerosis by promoting the uptake of LDLs by macrophages
List the risk factors associated with CAD?
Smoking High BP Diabetes High Cholesterol Obesity Sedentary Lifestyle Family History of CAD
What is CAD?
Coronary Artery Disease - The effects of the accumulation of atherosclerotic plaques in coronary arteries that lead to a reduction in blood flow to the myocardium
Why does hypertension put a strain on the heart?
It increases aortic pressure meaning the pressure in the Left Ventricle must be higher to overcome this pressure and move blood out into the aorta. Eventually ejection gets harder and stroke volume and cardiac output diminish.
List some negative inotropic agents which reduce the heart muscle contractility?
Calcium channel blockers
Some anaesthetics
List some positive inotropic agents affecting stroke volume
Neurotransmitters - norepinephrine
Hormones - epinephrine and thyroxine
Drugs - Digoxia
What are inotropic agents?
Substances that increase or decrease contractility in cardiac muscles (and consequently increase or decrease stroke volume)
What 3 factors affect stroke volume?
PRELOAD (Stretch of ventricle muscle prior to contraction)
CONTRACTILITY (forcefulness of ventricular muscle contraction)
AFTERLOAD (Pressure that must be overcome before ventricles can eject blood)
What effect to Calcium ions have on the heart?
A moderate increase in Ca 2+ (extra or intracellur) increases heart rate and contraction force.
What affect to elevated levels of sodium and potassium ions have on the heart
Decreased heart rate and contraction force
What hormones affect heart rate?
Thyroxine
Epinephrine
What is one of the signs of hyperthyroidism?
Tachycardia
What can trigger the adrenal medullae to release hormones?
Exercise
Stress
Excitement
What effects do norepinephrine and epinephrine have on the heart?
They enhance the heart’s pumping effectiveness by increasing both heart rate and contraction force.
Which part of the body releases epinephrine and norepinephrine?
Adrenal Medullae