T3 L3: How the CVS fails Flashcards
What is the opposite of turbulent flow?
Laminar flow. Flow is slower at the edges because of friction
Where is NO secreted?
Endothelial cells
What is an AMI?
An acute myocardial infarction. Onset is within minutes. Large or multiple infarcts like this can cause heart failure
What is the immune action response that causes atherosclerosis?
When there is a tear in the endothelium leading to an accumulation of white blood cells and fatty deposits
What is the main symptoms of coronary heart disease?
Angina
When do atheroma’s become dangerous?
When the fibrous cap bursts and can lead to formations of emboli
What are haemodynamic abnormalities?
BP inconsistencies
Name 3 systemic activities that help compensate during heart failure
Increased heart rate, increased contractility, and increased peripheral resistance
What is meant by osmotic and hydrostatic pressure in vessels?
High hydrostatic pressure causes water to leave the vessels, high osmotic pressure causes water to enter the vessels. Veins should have a higher osmotic pressure than arteries
What type of heart failure causes pulmonary oedema?
Let heart failure because water is backing up from the left side
What is orthopoea?
Can only breathe when sitting or standing
What is dyspnoea?
Difficulty breathing
What is ascites?
Accumulation of fluid in the peritoneal cavity. Can be caused by heart failure
What is decompensated heart failure?
The failure of the heart to maintain adequate blood flow after long term CVD
What are the 2 types of cardiac remodelling?
Hypertrophy and dilation
What 2 drugs can be used to inhibit cardiac remodelling?
ACE inhibitors and spironolactone
When is ventricular hypertrophy normal?
In athletes
What is the eccentric cause for ventricular hypertrophy?
Dilation because of volume overload
What is the concentric cause for ventricular hypertrophy?
Thickening because of pressure overload
What is another name for Vasopressin?
Antidiuretic hormone (ADH)
What is ADH and what is it’s effect on the body?
It’s a peptide secreted by the posterior pituitary gland that causes the kidneys to absorb more water.
What is Aldosterone and what is its effect on the body?
It’s a steroid secreted by the adrenal cortex that causes the kidneys to absorb more NaCl and therefore more H2O. It directly decreases natriuresis
What is natriuresis?
Excretion of sodium in the urine
What effect does decreased diuresis have on BP?
Increased BP
What do diuretic drugs do to diuretic hormones?
They antagonise them leading to fluid loss
What effect does increased fluid retention have on aldosterone and ADH?
Increased aldosterone and ADH secretion
Where is Renin secreted?
Kidneys
Where is ACE secreted?
Lungs and kidneys
Describe the formation of aldosterone including precursor molecules
Angiotensinogen (precursor molecule) is converted to angiotensin I by renin. Then ACE converts it into angiotensin II which is active and can develop into aldosterone
What type of drug is indapamide?
A thiazide-like drug that blocks the reabsorption at the DCT of the nephron
What type of drug is furosemide?
A loop diuretic that blocks reabsorption in the thick loop of the nephron
What type of drug is spironolactone?
A K+ sparing diuretic that inhibits aldosterone receptors in the cortical collecting duct
What is the difference between chronic low output heart failure and decompensated heart failure?
Decompensated heart failure is a medical emergency but people can live with it chronically. Chronic form is a disease of the elderly
What are the symptoms of left heart failure and why do they happen?
Respiratory symptoms. The right heart pumps into the lungs but the left atrium is full so hydrostatic pressure increases in pulmonary circulation. Also known as congestive heart failure because the pulmonary vasculature is congested. In extreme cases, fluid can leak out of vessels and into the lungs
What are the symptoms of right heart failure and why do they happen?
Systemic symptoms. The blood can’t return to the right heart because its full. This causes an increase in central venous pressure and therefore peripheral oedema or acites
What is paroxysmal nocturnal dyspnoea?
Waking up in the middle of the night and not being able to breathe
What are the 3 main symptoms of heart failure?
Fatigue, peripheral oedema and dyspnoea
What is cardiogenic shock?
Critically low perfusion due to low cardiac output. Defined as <90 mmHg systolic
How is positive feedback involved in cardiogenic shock progression?
The heart doesn’t have enough blood so it beats slower
How is cardiogenic shock treated?
Aggressive IV fluid and oxygen and airway maintained
What 3 types of drugs are used for chronic heart failure?
ACE inhibitors to prevent heart remodelling, Diuretics to increase the amount of fluid loss, and beta blockers to lower sympathetic activity
What is the sympathetic activity for homeostasis for low cardiac output (fast response)?
Happens to increase BP. Heart rate and contractility increase and there is vasocontriction
What is the slow response of the kidneys for homeostasis for low cardiac outpu?
Decreased glomerular filtration rate. Increased central venous pressure, venous return and preload
How do the kidneys make decompensated heart failure worse?
The kidneys increase plasma volume to compensate for poor perfusion of renal tissue because the kidneys can’t tell the difference between heart failure and haemorrhage. This process leads to fluid overload. The heart can’t pump this extra fluid and this leads to rapid deterioration
