Cardiovascular Disease Flashcards
What is the cardiovascular system?
~Responsible for delivering blood to different parts of the body
~organs & tissues
~Heart (muscular pump forces blood around body)
~Closed system of blood vessels
What is the vena cava?
~inferior vena cava brings deoxygenated blood from the lower half of the body to the right atrium
~Superior brings deoxygenated blood from to top half of the body to the heart
What is the aorta?
Largest artery - connects left ventricle of the heart to all body tissues (except lungs)
What is the carotid artery?
In neck - brings blood to brain and head
What is a thrombus and what risks factors are associated with it?
~intravascular (within peripheral blood stream) blood clot
Risks include
1 - slow blood flow e.g. hypotension, CHD, long air flights
2- damages the smooth intimal lining of the blood vessels - cholesterol, ketoacidosis, diabetes
3- increased blood coagulation - thrombocytosis
What risk factors are associated with blood coagulation?
~some malignant diseases & disorders of blood clotting
~pregnancy - increased blood production
~childbirth
~Oral contraceptives (oestrogen) “The Pill”
~use of tampons & moon cups - blood held in vaginal cavity
~standing for long periods of time e.g. cashiers
What is deep vein thrombosis?
~usually occurs in the veins of the lower limb e.g. pelvic & iliac regions
~Pain & swelling - tends to be asymptomatic in deeper veins
What is an embolus?
~Mass of any material being carried by the blood
~Most Common - fragment of a thrombus - deep vein thrombus - may cause pulmonary embolism (piece of thrombus carried via blood vessels to lungs)
What material can be emboli?
~Pieces of thrombi
~Amniotic fluid emboli
~Tumour fragments - may cause metastases
~Nitrogen bubbles in decompression sickness (bends)
~Fragments of atheromatous plaques
Air emboli - puncture of blood vessel by broken rib, phlebotomy, surgery
What is an embolism?
~Travelling embolus lodges and obstructs a blood vessel
~Pulmonary embolism in lungs, blockage of coronary arteries - myocardial infarction, blockage of cerebral artery - cerebral infarction
What is infarction?
Tissue death due to interrupted blood supply - may result in amputation
What is ischaemia?
Tissue damage due to reduced blood flow - angioplasty to get rid of obstruction
What is shock?
~Metabolic needs of a cell are not met due to inadequate blood flow
~Caused by reduction in circulating blood volume, blood pressure, & cardiac output
~Causes hypoxia - inadequate supply of nutrients & accumulation of waste products
~ causes pale skin. weak but rapid pulse, irritability, thirst, irregular heart beat, dizziness, sweating
What is hypovolaemic shock?
~Blood volume falls by 15-25% - reduced cardiac output
~caused by severe burning (plasma lost), haemorrhages, emesis & diarrhoea (water & electrolytes lost)
What is cardiogenic shock?
~Acute heart disease - damage to muscle can’t maintain adequate cardiac output
~Inadequate blood flow to tissue e.g. myocardial infarction
What is septic shock?
~Bacteraemic endotoxin - bacterial endotoxin in blood - massive inflammatory & immune response - powerful mediators released
~Hypotension - widespread vasodilation, depression of myocardial contractibility, poor tissue perfusion. & tissue death
~Multiple organ dysfunction
What is neurogenic shock?
~Vasovagal attack-fainting
~Caused by sudden acute pain, severe emotional experience, spinal anaethesia, & spinal chord damage
~Excessive parasympathetic activity or decreased sympathetic activity - reduce heart rate & cardiac output
~Extensive vasodilation - hypotension - reduce blood supply to brain - fainting - short period
What is anaphylactic shock?
~Anaphylaxis - severe allergic response e.g. penicillin & peanuts
~Vasodilation - release of mediators e.g. histamine & bradykinin
~Severe bronchoconstriction - respiratory difficulty & hypoxia
~Sudden onset - can cause death
What is compensatory shock?
~Blood pressure falls - reflexes stimulated & hormone secretion
~Pressure increased by increased peripheral resistance, increased blood volume, increased cardiac output
~Compensatory mechanisms or medical intervention - perfusion of heart & brain maintained
What is uncompensated shock?
~Self perpetuating with deteriorating cardiovascular function
~Hypoxia - cellular metabolism shifts to anaerobic pathways - lactic acid accumulation - progressive acidosis (capillary damage)
~Increased permeability - leaking fluid from vessels - lower blood pressure & tissue perfusion
~Waste products accumulate - vasodilation - hard to control blood pressure
~Organs deprived of oxygen
~Brain including cardiovascular & respiratory centres - starve of oxygen & nutrients
~lead to brain stem damage - death
What is atheroma?
~Deposition of lipids (cholesterol) in walls of arteries
~Patchy changes in tunica intima of large & medium sized arteries
~Plaque=cholesterol, other lipids, excess smooth muscle, fat filled monocytes (foam cells) - covered in fibrous cap
~Plaques cause swelling that spread into the lumen of blood vessel
~Ruptures plaques may rupture-expose sub-intimal material to blood in which platelets adhere - may cause thrombosis
~Heart, brain, kidneys, small intestine, & lower limbs
Cholesterol in bloodstream-production, composition, use in body, transportation
~Produced in liver & from diet
~Constituent of cells (brain cells & steroid hormones)
~Transported with triglycerides & phospholipids as lipoproteins
~Neutral lipid core (TAG & esterified cholesterol) - surrounded by coat of hydrophilic phospholipids & cholesterol
Size of lipoproteins: Big - small
1 Chylomicron (can change shape & breakdown)
2 VLDL
3 IDL
4 LDL
5 HDL
Reference ranges for cholesterol
Total cholesterol: <5.5mmol/L
HDL: >1.0mmol/L
LDL: <3mmol/L
Total Cholesterol : HDL: <4
Triglycerides: <2mmol/L
What happens in regards to cholesterol after a meal?
~CM enter circulation @ 30 minutes - peak is at 2-4 hours (low VLDL secretion)
~CM conc. falls with time
~VLDL increases as insulin levels decrease
~IDL&LDL
What causes atheroma?
~Fatty streaks present in infants - absorbed
~Failure to absorb fatty streaks - lead to atheromatous plaques in later life
~Begin in childhood - present in older people
~Lifestyle - high fat intake, low exercise levels
What is atherosclerosis?
The presence of plaques in the circulatory system
Risk Factors for atherosclerosis?
~Hereditary
~Obesity
~Gender (common in males, females after menopause - protective effect of oestrogen)
~Diet - high saturated fats & cholesterol
~Older age
~Smoking
~DM
~Excessive emotional stress
~sedentary lifestyle
~Hypertension
~Alcohol
Effects of atheroma
~Partial/complete blockage of artery
~Thrombus formation - lead to ischaemia & infarction
~Embolisms
What is the occlusion of arteries
~Completely blocks - infarction - tissue degenerates & dies
~Coronary artery - myocardial infarction
~Cerebral artery - cerebral ischaemia - cerebral infarction (stroke)
Narrowing of arteries
~Tissue distal to affected artery - ischaemia - receive enough blood for minimum needs but not enough for increased metabolic rate - acute cramp like ischaemic pain
~Angina pectoris - ischaemic pain in heart
~
Complications of atheroma
~Infarction & Thrombosis - fibrous cap overlying plaque breaks doen - platelets activated - thrombus forms - blocking artery - may cause emboli to break off - further infarction
~Haemorrhage - plaques calcified - artery becomes brittle, rigis, unresponsive to blood pressure shifts - rupture causing haemorrhage
~Aneurysm - local dialtion of arterial wall due to weakness - may rupture - fatal in aorta
~Hypertension - glaucoma
What is hypertension?
~High blood pressure - narrowing of arterioles
~Strain on heart
~Causes include excess sodium intake, cigarettes, alcohol, caffeine, hereditary, old age, stress, saturated fats, obesity
What is angina pectoris?
~Pain in chest (radiates to left shoulder & arm)
~Lack of oxygen supply to heart (physical exertion & partial blockages)
What are varicose veins?
~ excessive dilation of vessel - valves don’t close - backflow - usually in legs
~Veins lose elasticity - enlarged & fibrous tissue replaces tunica media
What are the risk factors of varicose veins?
Hereditary, female gender, pregnancy, age (loss of elasticity in older patients - less effective recoil), reduced efficiency of skeletal muscle pump from prolonged standing, sitting
What are angiomas?
~Benign tumours of blood vessels (haemangioma) and lymph vessels (lymphangioma)
~Excessive growth of blood vessels in uncharacteristic manner & interspersed with collagen fibres
What is oedema?
~excess tissue fluid accumulation - swelling
~Pulmonary oedema - venous congestion in lungs & increased pulmonary vessel permeability - accumulation of fluid in alveoli - less area for gas exchange - dyspnoea (breathlessness), cyanosis (skin at lips, extremities turn blue), foamy sputum
~Causes of pulmonary oedema - cardiac failure, inflammation, irritation of lungs, excessive infusion of IV fluids
What is thrombocytopenia?
~Low count (150000-450000 per μl normal)
~ low platelet production, increased platelets in spleen, increased breakdown of platelets
~Bruise easily
~Treat with steroids, transfusions, spleen enlargement or removal
What Causes thrombocytopenia?
