Lecture 6 Coronaries and Veins Flashcards
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
- infarction of area with stagnant blood, tissue death
- subendocardial muscle is usually more reliant on O2 (more active) so most damaged
Causes of death after myocardial infarction include:
- Systolic stretch, decreased cardiac output
- Lower gas exchange from pulmonary edema
- Fibrillation
- Rupture of heart
What is useful about veins being temporary blood reservoirs?
When dehydrated or hemorrhaged, veins constrict and release blood to maintain arterial pressure even in the loss of blood volume
Define vascular capacitance:
The total quantity of blood that can be stored in a given portion of the circulation for each mmHg
How is capacitance calculated?
Distensibility times volume divided by increase in pressure
How can veins compensate for changes in blood volume?
Veins can constrict to transfer more blood into the heart, increasing cardiac output. They can also ‘buffer’ pressure changes by absorbing extra pressure from drinking or transfusions.
