week 7 - disorders of cardio part 2 Flashcards
What are the 3 layers of the heart wall?
epicardium
myocardium
endocardium
What is the pericardium?
It is a sac that encloses the heart
What is the epicardium?
Part of the pericardium.
Outer layer of the heart.
Keeps heart in position, prevents friction.
Thin layer.
What is the myocardium?
The middle layer, most thickest.
Contractile layer composed of cardiac muscle
What is the endocardium?
Innermost layer of the heart wall.
A thin layer.
Lines the chambers and regulates myocardial function
What is pericarditis?
It is a disorder of the pericardium caused by inflammation.
The inflammation can be caused by:
Tumour
Autoimmune conditions
Viruses/bacteria
Uraemia
Some drugs
How does pericarditis affect cardiac function?
The inflammation causes friction during contraction of the heart, chest pain and scratch rubbing sound.
This increases the effort required by the heart leading to symptoms like shortness of breath, coughing and fatigue.
What can the coughing symptom of pericarditis lead to and what is it caused by?
The coughing in pericarditis is caused by venous hypertension leading to pulmonary oedema
What is cardiac tamponade?
The accumulation of fluid or blood between the 2 layers of the pericardium – can be caused by viral, bacterial, cancer, injury etc
All this fluid puts pressure on the heart so the heart can’t pump blood properly.
The heart cannot expand fully so doesn’t full fully with blood
What can cardiac tamponade lead to?
It can lead to reduced tissue perfusion – a lack of oxygenated blood flowing to areas of the body
Leads to faster heartbeat, reduced blood pressure, accelerated breathing, paradoxical pulse.
What is paradoxical pulse?
Pulse weakens when breathing in and strengthens when breathing out due to changes in intrathoracic pressure.
What is endocarditis?
Disorders of the endocardium caused by inflammation of the endocardium.
Onset takes weeks/months
What are the symptoms of endocarditis?
Symptoms are due to embolisation:
stroke, ischaemia - reduced blood supply
limb pain
abdominal pain
Can lead to:
Malaise
Anorexia
Fatigue
Low grade fever
Night sweats
Headache
Backache
Heart murmur
It can lead to heart failure due to decreased CO.
What is infective endocarditis?
The colonisation of the endocardium by microbes
What can infective endocarditis cause?
It can cause structural abnormality, leading to turbulent fast blood flow leading to platelet thrombi forming and dissolving – Virchow’s Triad
How can you tell whether an organism (like a microbe) will cause infective endocarditis?
By determining the organism’s affinity of binding to platelets/thrombi due to endocardial structure. – some examples maybe
What is cardiac diastole?
The filling of the ventricles with blood
What is cardiac systole?
This is where the ventricles pump out most of the blood (60%)
What are some causes of the impaired contractile ability of the heart?
Infections
Tumours
Ischaemia
Drugs
Toxins
Commective tissue diseases
Endocrine diseases
What is hypertrophic cardiomyopathy?
When the size of an organ/tissue increases in size, due to enlargement of cells NOT by multiplication of cell.
It obstructs blood flow from the left ventricle
Has genetic causes – 50% autosomal dominant
Can result in sudden death under stressful conditions – like competitive sport