When the cardiovascular system goes wrong Flashcards
What mechanisms is hypertension associated with?
- Venous return
- Filling time
- Hormones
- Vasoconstriction/ dilation
What mechanisms is Atherosclerosis/ thrombosis/CAD associated with?
- Venous return
- Vasodilation/constriction
- Contractility
What processes are valve defects associated with?
- end diastolic volume
- end systolic volume
What processes are arrhythmias associated with?
- EDV
- ESV
- Heart rate
What mechanisms is heart failure associated with?
- Contractility
- Stroke volume
What is hypertension?
associated with high blood pressure
What are the two types of hypertension?
Primary and Secondary hypertension
Give features of primary hypertension
- Unknown medical cause
- Essential/idiopathic
- Linked to: genetic predisposition, alcohol intake, obesity, lack of exercise, diabetes, intrauterine environment, etc
Give features of secondary hypertension
- Of known medical cause
- Kidney disease – increased angiotensin II leading to vasoconstriction and expansion of extracellular fluid
- General endocrine disorders e.g. diabetes
- Adrenal medulla diseases (phaeochromocytoma) – excessive adrenaline secretion
How can you treat hypertension?
- Angiotensin converting enzyme inhibiter or angiotensin II receptor blockers inhibit the actions of angiotensin II of aldosterone production thereby preventing renal Na+/H2O absorption and blood volume increase, and prevents vasoconstrictor actions of angiotensin II
- Calcium channel blockers inhibits Ca-channels in cardiac muscle and vascular smooth muscle cells preventing depolarization. Thereby decreasing CO and causing vasodilation, respectively
- Thiazide diuretics increase Na+ and water loss, thereby decreasing fluid volume which decreases venous return and cardiac output
- A-Adrenoceptor antagonists (a-blockers) reduce TPR by inhibiting the action of noradrenaline
- B-Adrenoceptor Antagonists (B-blockers) decreases Cardiac output and SNS activity centrally, decreases renin release leading to favourable secondary actions
What is hypertension a risk factor for?
- Atherosclerosis
- Stroke
- Heart failure
- Renal failure
- Aneurysms (weakened arterial walls due to elevated pressures over a number of years – eventually ruptures – results in immediate death in major blood vessel such as aorta)
What is atherosclerosis and how does it form?
- Associated with the occlusion of blood flow through blood vessels
- Fibrous cap of a dense extracellular matrix narrows lumen of vessel and restricts blood flow
- Cap formed from Lipid accumulation, macrophages, proinflammatory mediators, white cells, endothelial cells, smooth muscle cells etc
What can atherosclerosis lead to and how?
- can lead to a thrombosis
- fragments of plaques can detach and lodge in small vessels
What is a thrombosis?
When a blood clot forms in a vein
where is a thrombosis most commonly found?
• Most commonly found in a leg vein: deep vein thrombosis (DVT)
- Most of the problems will start and progress around veins
- Stasis of blood in venous return
- Can lead to pulmonary embolisms as clots may travel around the circulatory system
What is a blood clot in the lungs called?
A pulmonary Embolism
What are other names for coronary artery disease (CAD)
- ischaemic heart disease
- heart attack
When does CAD occur?
When blood flow to the myocardium is insufficient for its needs
What is angina pectoris?
ischemia-induced pain mediated by endogenous vasodilators (coronary vasodilators)
- If tissue becomes compromised (dies) then molecules (endogenous vasodilators) become released and attach to pain receptors
- Angina pectoris is an early warning sign of a CAD
Where is CAD most frequent?
- in the left ventricle
What is the most common cause of CAD?
atherosclerosis of a coronary artery
How quickly does the heart muscle start to die with insufficient supply of blood?
within 20 minutes