Cardio Week 5 Flashcards
Define ischaemia
Deficiency, real or relative, of blood in a tissue causing a shortage of oxygen and impaired aerobic respiration
Hypertension is a risk factor for which diseases?
- MI, stroke, TIA
- aneurysm
- atherosclerosis
- ischaemic heart disease
- renal failure
- death
Risk factors for hypertension are?
- Obesity - Smoking - Diet - Stress
What is the difference between atherosclerosis and arteriosclerosis
Atherosclerosis is the stiffening of a vessel wall due specifically to an atheromatous plaque while arteriosclerosis is any stiffening of a vessel wall.
What are three causes of ischaemia?
- Increases demand for O2 that is not met 2. Narrowing or block in supplying vessel 3. Systematic reduction in tissue perfusion
What is a dissection?
Blood entering and flowing in the media of the a vessel.
Which body systems directly effect BP? How?
The heart - CO
The vessels - TPR
The kidney - blood volume
What do angiotensin system inhibitors target?
Angiotensin converting enzyme inhibitor (the “prils”)
- decrease vascular tone
- decrease aldosterone production
- decrease cardiac hypertrophy
Angiotensin receptor inhibitors (AT1 and AT2)
- decrease vasocontriction
- decrease aldosterone
- decease cardiac hypertrophy
- decease sympathetic activity
What are three causes of hypoxia?
- Deficient blood supply to a tissue (ischaemia)
- Reduction in O2 carrying capacity of blood eg anaemia
- Impaired respiratory function
What was the advantage and disadvantage of methicillin?
Adv: acts on penicillin resistant staphlococci Disadvantage: quite toxic - Flucloxacillin and dicloxacillin are less toxic
How do thiazide diuretics act?
Inhibit Na+/Cl- cotransporters in distal convoluted tubule > decrease Na and Cl reabsorption in renal tubules > increase Na conc. excretion from kidney > reduce blood volume and blood pressure
What is a aneurysm?
Dilation of vessel wall due to weakening of the media.
What are the affects of calcium channel blockers?
Inhibit voltage-gated L-type Ca2+ channels in myocardium and vasculture - reduce cardiac/vascular contractility - reduce vascular resistance
What effect does aldosterone have?
Salt and water retention - Increase fluid volume
Define cardiac remodeling
A increase in relative wall thickness without an overall increase in LV mass, overall the heart gets smaller.
Define eccentric hypertrophy
Increase in LV mass with no relative increase in wall thickness (total heart volume increases). A response to volume overload - increase LVEDV and ejection fraction to maintain SV. More sacromeres in series.
What pharmacological properties are altered in semi-synthetic drugs?
Pharmacokinetics Reduce toxicity Spectrum of action
What are 4 causes of Oedema
Heart failure
Decrease in osmotic pressure due to reduced plasma proteins
Block lymphatics
Increased capillary permeability
What is the vaso vasorum?
Small vessel which supply the adventitia in large blood vessels.
How to identify LV hypertrophy?
Clinical Examination – Forceful/displaced apex beat, S4, S3
ECG – tall voltages, T wave inversion
Chest XR – large heart in eccentric LVH (may be normal size in concentric LVH
Echo/MRI/Cardiac CT
Define hypoxia
Lack of O2 in tissue
What are five targets of antibiotics?
Cell wall - eg beta lactams
Cell membrane - polyenes (best anti-fungal)
Nucleic acid
Folic acid
Ribosomes
What the affects of beta-adrenoceptors antagonists? What are they called?
“the olols”
- reduce cardiac output acutely
- reduce HR and contractility
- reduce renin release
- reduce blood volume and TPR
What are some causes of LV hypertrophy?
Pressure overload - hypertrophy, aortic valve stenosis (concentric)
Volume overload - mitral and aortic valve regurgitation
Obesity
Hypertension
Following MI
Diabetes
Renal Failure
Genetic - Fabry’s disease
What are the three layers that blood vessel walls are divided into?
Intima, media, adventitia
What is the mechanism of atherosclerosis?
Endothelial dysfunction initiated via a variety of risk factors • LDL entry and oxidation e.g. via ROS • Cytokine production • Recruitment of monocytes – Expression of leukocyte adhesion molecules on endothelium • Selectins • VCAM-1, ICAM-1 – Chemoattractant signals e.g. IL8, MCP-1 – Phagocytosis of lipids and formation of foam cells • Recruitment of lymphocytes • Recruitment of smooth muscle cells from the media and formation of extracellular matrix e.g. stimulated by PDGF and TGF beta • Degeneration of components of plaque by e.g. apoptosis and matrix metalloproteinases, forming lipid rich necrotic core • Initial remodelling of vessel wall preserves lumen diameter • Continued endothelial dysfunction: altered release of vasoactive substances, alteration of normal antithrombotic properties • Eventually variable combination of vessel stenosis, impaired vasodilation, plaques vulnerable to rupture, local prothrombotic environment
What is the advantage of ampicillin?
Spectrum of action includes gram -ve rods. Newer, very similar, version is called amoxycillin
What was the advantage of penicillin V?
Oral administration
Define concentric hypertrophy
Increase in LV mass and wall thickness relative to the lumen volume. Due to pressure overload - thicker wall decreases or normalises wall stress. More sarcomeres in parallel
What are the 5 classes of antihypertensive drugs?
Angiotensin system inhibitors
Beta-adrenoceptor antagonists
Calcium channel blockers
Diuretics
Other
What effect does angiotensin II have?
Acts on AT1 receptors to cause vasocontriction
Cell growth and remodelling of the heart
Positive feedback to renin production
Aldosterone production
ADH production in the post. pituitary
What is the advantage of carbenicillin?
It is affective against Pseudomonas aeruginosa
