Lecture 6 - Coronaries and veins Flashcards
(21 cards)
What are the three types of cardiac veins?
Coronary sinus, anterior cardiac veins, and Thebesian veins
Why does blood flow fall during ventricular contraction?
Because the muscle is contracting so no blood can flow through it
Name 2 ways coronary flow is controlled
Local control like muscle, nervous control that is less powerful
Where does the heart’s energy supply come from in the fed state?
Krebs cycle and glycolysis
Where does the heart’s energy supply come from in the fasting state?
Fat, lactic acid, ketone bodies
What causes the chest pain during ischemia / hypoxia / coronary stenosis or blockage?
The use of glucose and production of lactic acid as a metabolite during respiration without O2
Name 5 factors of ischemic heart disease
Aging, male, genetics, diabetes
Cigarettes, cholesterol, lack of exercise, blood pressure
Define atherosclerosis
The buildup of plaques made of fats and cholesterol
Define arteriosclerosis
Rigid arteries
Name 3 key steps of atherosclerosis
- Cholesterol and fats get below endothelial layers
- Turbulent flow and inflammation + scarring
- Reduced lumen, possibly even acute occlusion
What can worsen the symptoms of mild ischemic heart disease and how is it diagnosed?
Exacerbated by exercise, fear, cold exposure, full stomach.
Diagnose with treadmill stress test
Symptoms of mild vs severe ischemic heart disease:
Mild: chest pain, radiates to left arm, shoulder, neck
Severe: thrombus/blood clot, embolus if in circulation
What happens in ischemic heart disease to avoid complete occlusion of smaller arteries?
Vascular remodeling
How can you treat ischemic heart disease?
Coronary bypass or coronary artery angioplasty
What is myocardial infarction (obstruction of local blood supply)?
Chronic obstruction by atherosclerosis leading to thrombus/embolus, and coronary spasm (sudden sustained contraction in artery)
Process of myocardial infarction:
Blood flow stops, local vasodilation, no oxygen coming in or blood going out –> tissue death
Causes of death after myocardial infarction include:
Systolic stretch - severely decreases cardiac output
Pulmonary edema - increased capillary pressures in the lungs -> lower gas exchange
- Ventricular fibrillation or rupture of heart
What is useful about veins being temporary blood reservoirs?
Veins can contract and re-establish appropriate BP by the venous pump
Define vascular capacitance:
Total quantity of blood that can be stored in a given portion of the circulation for each mmHg
How is capacitance calculated?
Change in volume / change in pressure
How can veins compensate for changes in blood volume?
They have a high capacitance, they can dilate and restrict depending on the volume of blood, stabilising blood pressure
