case 2 Flashcards
what happens microscopically in coagulative necrosis?
initially no change then progressive loss of nuclear staining accompanied by loss of cytoplasmic detail.
what happens to the texture of the tissue in coagulative necrosis?
Initially normal/firm texture then softens as tissue is digested by macrophages.
what is dry gangrene?
reduced blood supply due to vascular problems.
what is wet gangrene?
infection, swelling from infection occludes blood vessels, superimposed liquefactive necrosis.
what is gas gangrene?
muscle necrosis causing sepsis and gas production, commonly clostridium perfringens (type of bacteria)
what is paroxysmal nocturnal dyspnoea?
when patients wake up in the middle of the night gasping for breath
what heart condition is paroxysmal nocturnal dyspnoea seen in?
pulmonary oedema.
what type of heart failure is paroxysmal nocturnal dyspnoea related to?
left sided
what is syncope?
medical term for fainting or passing out
what does idiopathic mean?
any disease or condition which arises spontaneously or for which the cause is unknown.
what is kussmaul’s sign?
paradoxical rise in JVP with inspiration.
what is gastrulation?
the formation of the germ layers.
in which weeks is it a pre-embryo?
weeks 1-2
in which weeks is it an embryo?
weeks 2-8
what is a blastocyst?
pre-embryo with cavity.
what does congenital heart disease involve?
ASDs (atrial septal defects) and VSDs (ventricular septal defects)-commonly known as holes in the heart.
what are progenitor cells?
populations of specific cell types that contribute to the development of specific anatomical structures.
what can defects in cardiac progenitor cells lead to?
VSD (ventricular septal defect)
tetralogy of fallot
what is tetralogy of fallot?
combination of 4 congenital abnormalities:
- VSD
- pulmonary valve stenosis
- misplaced/overriding aorta
- right ventricular hypertrophy
what happens in congenital pulmonary valve stenosis?
deformity on or near pulmonary valve narrows valve opening and slows blood flow
what happens in right ventricular hypertrophy?
right ventricular wall gets thickened
what is the first visceral organ to develop in the embryo?
heart
around how many weeks does the heart develop?
3 weeks
what is phospholamban?
protein that regulates Ca2+ ATPase pump in the cardiac myocytes.
what does phospholamban do?
when not phosphorylated inhibits Ca2+ ATPase pump
when phosphorylated loses its ability to inhibit pump-increases contraction.
what is atrophy?
decrease in both size and number of cells resulting in a decrease in tissue or organ size.
what pathway is atrophy related to?
ubiquitin-proteasome pathway
what are the 2 types of atrophy?
physiological (normal) and pathological (abnormal)
what is an example of physiological atrophy?
right ventricle of heart visibly decreases in size after birth.
what is an example of pathological atrophy?
if you break your leg and can’t use your muscles and they experience atrophy.
what type of atrophy happens in Alzhiemer’s?
cortical atrophy-cortical matter shrinks.
what is hypertrophy?
increase in cell SIZE (NOT number) which results in an increase in tissue and muscle size.
what is an example of physiological hypertrophy?
muscular growth attained by doing weights
what is an example of pathological hypertrophy?
cardiac hypertrophy-when in heart failure heart muscle is chronically overloaded + cardiac muscle tries to adapt with hypertrophy.
what is hyperplasia?
increase in the NUMBER of cells, usually resulting in an increase of mass of organ or tissue.
what causes hyperplasia?
1) growth-driven proliferation of mature cells
2) increased output of new cells from tissue stem cells.
what is the relationship between hyperplasia and cancer?
hyperplasia doesn’t equal cancer but it can produce a more dangerous environment for cancer to develop.
what is metaplasia?
reversible change in which 1 differential cell type (mesenchymal or epithelial) is replaced by another.
to clarify: the epithelial or mesenchymal cells are the ones being replaced.
what are mesenchymal cells?
multipotent stem cells found in bone marrow.
in metaplasia, what is differentiation brought on by?
- cytokines
- growth factors
- extracellular matrix components
- transcription factors
how do extracellular matrix components cause differentiation?
promote expression of genes that drive cells towards a specific pathway of differentiation.
when does cellular injury occur?
when stress exceeds ability of cell to adapt.
what does the cell response to stress depend on?
1) severity of injury
2) type of cell-eg neurone can survive hypoxia for 3-5 mins but skeletal muscle can survive it for a long time.
what can chronic blood shortage lead to?
atrophy
what can acute severe blood shortage lead to?
parenchyma death
what is the parenchyma?
functional tissue of an organ as distinguished from the connective and supporting tissue.
what are the causative agents of cell injury?
hypoxia free radicals physical agents-eg hot and cold, blast injuries chemical-poisons or drugs biological-infectious organisms ionising radiation
what cell types are the most vulnerable to ionising radiation?
rapidly dividing ones: lymphoid tissue bone marrow mucosa of GI tract germinal tissue
what is germinal tissue?
tissue made of germ cells-that will go on to form sperm and eggs. found in ovaries and testes.
what happens to water on ionisation?
forms highly reactive radicals.
what is vasculitis?
inflammation of the blood vessels.
what colour does fibrinoid necrosis stain?
bright red/pink.
how does pancreatitis cause fat necrosis?
release of lipases causes enzymatic lysis of fats around the pancreas.
what is the usual flow of blood?
laminar.
describe laminar blood flow.
concentric layers of blood moving parallel down the length of a blood vessel-the highest velocity of blood in the centre of the blood vessel. (remember ur physics)
what are heart murmurs caused by?
turbulent (abnormal) blood flow through the heart.
what is pericarditis?
inflammation of the pericardium, often caused by viral infections.
what is cardiomyopathy?
a myocardial disorder in which the heart muscle is structurally and functionally abnormal with no underlying heart condition to explain it. (no coronary artery disease, hypertension, valvular, or congenital diseases.)
what is the most common cause of cardiomyopathy?
genetic
what can cardiomyopathy cause?
heart failure, arrhythmias, sudden cardiac death
what are the 4 main types of cardiomyopathy?
dilated
hypertrophic
restrictive
arrhythmogenic right ventricular
what is myocarditis?
inflammation of the myocardium-heart muscle
what is systemic lupus erythrematosus?
most common form of lupus-when the immune system attacks its own tissues.
what is thyrotoxicosis?
excess of thyroid hormone in the body.
what does a rhythm strip do in an ECG?
allows you to look at a more prolonged period of time.
what is normal sinus dysrhythmia/arrhythmia?
heart rate changes with your breathing.
what is an ectopic beat caused by?
ventricular muscle cell randomly fires-send wave in wrong direction around ventricles and they contract earlier than usual.
what happens to the QRS complex in an ectopic beat?
is wider-because the electricity is travelling abnormally through the ventricles.
what is a side effect of digoxin?
more ectopic beats.
if the P wave isn’t followed by a QRS, where is the problem?
the AVN-cos contraction has happened in atria but hasn’t been able to reach ventricles.
what does ST elevation usually happen in?
acute MI
what happens if the QT interval is too long?
risk of adverse CV effect being triggered.
how do CT scans work?
take a series of x rays at different levels and feed into processor to create 3D image.
what are some benefits of CT scans?
quick
less resource heavy
more accessible-hospitals usually have several Ct scanners running 24/7
what are some negatives of CT scans?
difficult in certain areas eg soft tissue-muscles, ligaments, tendons
exposure to ionising radiation.
about how much ionising radiation does 1 CT scan expose you to?
several years of background radiation.
what is precession?
change in orientation of rotational axis of a spinning body.
what is radiopaque dye?
dense liquid which dilutes in blood but doesn’t allow x rays to penetrate it.
what is orthopnea?
difficulty breathing when lying down.
what is pro-BNP?
hormone secreted by cardiomyocytes in the heart ventricles in response to stretching or fluid overload.
what is a key test for heart failure?
pro-BNP-if they don’t have elevated pro-BNP it’s highly unlikely they have heart failure.
what is a key part of heart failure management?
healthy lifestyle changes-balanced diet, exercise, no smoking.
what are most heart failure drugs aimed at?
reducing the compensatory effects of the body due to the decreased cardiac output.
how does the body compensate for decreased cardiac output in heart failure and what are the effects of this?
stimulates RAAS-increased heart rate, vasoconstriction, body retains more fluid-these all ultimately increase afterload so make the heart failure worse.
what do some heart failure patients require and why?
pacemaker or implantable defibrillator- severe heart failure can cause disorganised contractions or rhythms.
what is shock?
a critical condition brought on by a sudden drop in blood flow through the body.
what are the 4 types of shock?
cardiogenic
septic
anaphylactic
hypovolaemic
what is cardiogenic shock?
mechanical or electrical failure of the ventricles, eg due to cardiac tamponade or post MI.
what is septic shock?
vasodilation due to bacterial toxins leading to a drop in blood pressure.
what is anaphylactic shock?
exaggerated immune response.
what can hypovolaemic shock be caused by?
haemorrhage
blood plasma loss due to severe burns
severe loss of fluid eg vomiting, diarrhea.
in a young fit healthy person, how much of their blood can be lost before their blood pressure starts to drop?
about 30%.
when does ability to compensate for blood loss drop?
old age
myocardial or respiratory diseases
drugs eg beta blockers
draw out a flow chart of CV response to haemorrhage-answer’s in ur notebook.
go do it
what are the 5 risk factors that present the greatest risk of developing heart disease?
1) smoking
2) diabetes mellitus
3) hypertension
4) hypercholesterolaemia
5) physical inactivity
what is an inferior MI?
infarction of right coronary artery - supplies inferior aspects of the heart.
what ECG leads can you see an inferior MI on?
II, III, aVF
how does smoking increase risk of thrombus formation?
chemicals on tobacco smoke damage the vascular endothelium of the blood vessel, increasing development of atheroma.
how is a blood clot formed from an atheroma?
turbulent blood flow -cap of atheroma breaks off-softer material exposed-platelets aggregate.
what is compliance?
property of a chamber that describes how easy it is to fill- how much of a change in pressure causes a change in volume. high compliance=easier.
what are the 2 types of ischaemic heart disease?
chronic
acute
what is the 6 month mortality rate of infective endocarditis with treatment?
20-25%
what are the 2 features of infective endocarditis?
endocardial damage
bacteria
what is the endocardium?
inner lining of the heart. includes heart valves.
what is infective endocarditis?
infection of the endocardial surface.
what types of phenomena can features of endocarditis be caused by?
1) vascular phenomena (septic emboli)
2) immunological phenomena
what is an infarct?
small localised area of dead tissue that has died from lack of blood supply.
what is the conjunctiva?
clear, thin membrane that covers part of the front surface of the eye and the inner surface of the eyelids.
what is dyspnoea?
difficult or laboured breathing.
what is a dermatome?
area of skin that’s supplied by a single spinal nerve.
what toxic substance does paracetamol overdose create in the body?
(acetaminophen) free radicals.
when can you call the pre-embryo the embryo?
after implantation.
when does the embryo become the fetus?
around 8 weeks.
what is the difference between the embryo and fetus stage?
fetus characterised by growth, embryo characterised by development of body systems.
what is the 1st organ to form in the embryo?
heart
what are positional words that in embryo terms all mean the head of the embryo?
cranial
rostral
anterior
what does rostral mean?
(from the Latin rostrum, to mean towards the nose/beak). therefore refers to the anterior (front) aspect of the head.
what does caudal mean?
comes from the word tail, means at the tail end.
what forms the trilaminar disc?
the 3 germ layers.
around how many days does heart development start to happen?
20 days.
what structure forms the flexible membranous component of the septum in atrial septation?
Septum primum
what is morbidity?
the condition of having a disease/the rate of disease in a population.
DEFINE rheumatic fever.
systemic, POST-STREPTOCOCCAL non-suppurative INFLAMMATORY DISEASE affecting the heart and extra- cardiac sites (eg joints, brain, skin)
what is a suppurative infection?
one that produces pus.
what are the 2 cardiac valves most commonly affected in rheumatic valvular disease?
mitral and aortic
what is haemoptysis?
the coughing of blood.
what are the typical clinical manifestations of mitral stenosis?
Dyspnoea
Fatigue
Dizziness/syncope
Palpitations
Oedema
Haemoptysis
Bibasilar crepitation or Crackles
Abnormal heart sounds:
o opening snap
o first heart sound (S1) is loud
o Diastolic murmurhow does mitral valve stenosis cause dyspnoea?
1) usually results from the elevation in left atrial pressure and pulmonary venous hypertension which leads to reduced compliance of the lungs and a decrease in vital capacity.
2) also may be related to an inability to increase the cardiac output with increased metabolic demands
what may result from abnormal reabsorption of the septum primum?
patent foramen ovale-cos of the remaining short septum primum not closing the foramen ovale.
why might inspiration ‘split’ the second heart sound?
the aortic valve closing before the pulmonary valve-the pulmonary valve may stay open longer due to an increased venous return to the right side of the heart, leading to a slightly longer ventricular emptying time on the right.
