Cardiovascular system Flashcards
What 3 factors regulate Cardiac Stroke Volume
- The degree of stretch in the heart before it contracts
- The forcefulness of contraction of individual ventricular muscle fibres
- The pressure required to eject blood from the ventricles
What is the inflammation of the endocardium typically involving the heart valves? [Mostly caused by bacteria]
[Bacterial] Endocarditis
What is myocarditis
Inflammation of the myocardium that usually occurs as a complication of a viral infection, rheumatic fever or exposure to radiation or certain chemicals or medications
Medical term for Heart Enlargement?
Cardiomegaly
What is Cardiac Catheterization
A procedure used to visualise the heart’s coronary arteries, chambers, valves and great vessels.
What is the medical term meaning cessation of an effective heartbeat
Cardiac Arrest
What is the medical term describing failure of the myocardium to contract
Asystole
Name the X-ray examination of the heart and great blood vessels after injection of a radiopaque dye into the bloodstream
Angiocardiography
List some types of arrythymias
SVT - Supraventricular Tachycardia Heart Block APC - Atrial Premature Contraction AF - Atrial Fibrillation VPC - Ventricular Premature Contraction VT/Vtach - Ventricular Tachycardia VF Ventricular Fibrillation
What does arrhythmia or dysrhythmia refer to?
An abnormal rhythm as a result in the conduction system of the heart. The heart may beat too fast or too slow.
What does PDA stand for and what is it?
Patent Ductus Arteriosus - A congenital heart defect
What are the treatments for myocardial infarction
Injection of a thrombolytic (Clot dissolving) agent e.g. streptokinase or tpa, plus heparin (anti-coagulant) OR Performing coronary angioplasty OR Coronary artery bypass grafting
What might happen if the size and location of an infarcted area of heart tissue is significant?
It may disrupt the conducting system of the heart and cause sudden death by triggering ventricular fibrillation
What happens to the heart tissue distal to an obstructed artery?
The tissue dies and is replaced by non-contractile scar tissue and consequently the heart loses some of its strength
What does infarction mean?
The death of an area of tissue because of interrupted blood supply
What might occur as a result of an obstruction to blood flow in a coronary artery?
Myocardial Infarction
Which areas of the body is the pain in angina pectoris referred to (in many instances)?
Neck
Chin
Down the left arm to the elbow
What is Angina Pectoris and what condition of the heart does it usually accompany?
It literally means “strangled chest” and is a severe pain. It often accompanies myocardial ischemia
What is Myocardial Ischemia
The medical term for a condition of reduced blood flow to the myocardium.
What drugs are used to treat coronary artery disease?
Anti-hypertensive drugs Nitroglycerin Betablockers Cholesterol lowering agents Clot dissolving agents (thrombolytic)
How are smooth muscle fibres involved in forming an atherosclerotic plaque?
They form a cap on top of the fatty streak formed by the foamy macrophages and T-cells
How is it that despite the formation of atherosclerotic plaques in the arteries, blood can flow through the affected arteries with relative ease sometimes for decades?
Atherosclerotic plaques expand away from the bloodstream rather than into it.
What is the difference in LDL and HDL? Which type is better for our health?
LDL - Transports cholesterol from liver to body cells for use in cell membrane repair and production of steroid hormones and bile salts
HDL - Removes excess cholesterol from body cells and transports it to the liver for elimination.
High levels of LDLs are associated with higher risk of CAD.
Why are high levels of LDL considered bad for our health?
They are associated with a increased risk of Coronary Artery Disease due to their promotion of atherosclerosis. They are often referred to as bad cholesterol.
Name two major lipo proteins
LDL - Low density Lipo proteins
HDL - High density Lipo proteins
Describe the structure of a lipo protein including where in the body they are made.
Manufactured by the liver and small intestine.
Spherical particle
Inner core of triglycerides and other lipids
Outer shell of proteins, phospholipids and cholesterol
What 3 substances make up an atherosclerotic plaque?
1) Fatty substances
2) Cholesterol
3) Smooth muscle fibres
How does Homocysteine possibly increase the likelihood of coronary artery disease?
It’s an amino acid that may induce blood vessel damage by promoting platelet aggregation and smooth muscle fibre proliferation
How does fibrinogen increase the risk of Coronary Artery Disease?
May help regulate cellular proliferation, vasoconstriction and platelet aggregation.
What is a Lipoprotein? (In relation to CAD)
LDL like particle
Binds to endothelial cells, macrophages and blood platelets
May promote proliferation of smooth muscle fibres
Inhibits breakdown of blood clots
What are C-reactive proteins?
Produced by Liver and maybe present in the blood in inactive form
Converted to an active form during inflammation
May play a direct role in development of atherosclerosis by promoting the uptake of LDLs by macrophages
List the risk factors associated with CAD?
Smoking High BP Diabetes High Cholesterol Obesity Sedentary Lifestyle Family History of CAD
What is CAD?
Coronary Artery Disease - The effects of the accumulation of atherosclerotic plaques in coronary arteries that lead to a reduction in blood flow to the myocardium
Why does hypertension put a strain on the heart?
It increases aortic pressure meaning the pressure in the Left Ventricle must be higher to overcome this pressure and move blood out into the aorta. Eventually ejection gets harder and stroke volume and cardiac output diminish.
List some negative inotropic agents which reduce the heart muscle contractility?
Calcium channel blockers
Some anaesthetics
List some positive inotropic agents affecting stroke volume
Neurotransmitters - norepinephrine
Hormones - epinephrine and thyroxine
Drugs - Digoxia
What are inotropic agents?
Substances that increase or decrease contractility in cardiac muscles (and consequently increase or decrease stroke volume)
What 3 factors affect stroke volume?
PRELOAD (Stretch of ventricle muscle prior to contraction)
CONTRACTILITY (forcefulness of ventricular muscle contraction)
AFTERLOAD (Pressure that must be overcome before ventricles can eject blood)
What effect to Calcium ions have on the heart?
A moderate increase in Ca 2+ (extra or intracellur) increases heart rate and contraction force.
What affect to elevated levels of sodium and potassium ions have on the heart
Decreased heart rate and contraction force
What hormones affect heart rate?
Thyroxine
Epinephrine
What is one of the signs of hyperthyroidism?
Tachycardia
What can trigger the adrenal medullae to release hormones?
Exercise
Stress
Excitement
What effects do norepinephrine and epinephrine have on the heart?
They enhance the heart’s pumping effectiveness by increasing both heart rate and contraction force.
Which part of the body releases epinephrine and norepinephrine?
Adrenal Medullae
What are baroreceptors and where are they located?
Sensory receptors
Provide input to Cardiovascular centre
They are neurons (nerve cells) sensitive to changes in Blood Pressure changes
Located in arch of the aorta and carotid arteries
Which nerves release the neurotransmitter acetylcholine and which nervous system do they belong to?
Vagus (x) nerves
Parasympathetic Nervous System
Which neurotransmitter decreases heart rate and which node does it affect?
Acetylcholine (ACh)
Sino-atrial Node - SA node
Which nerves sends signals to the CV Centre?
Glossopharyngeal (IX) nerves
Vagus (X) nerves
Where does the CV centre direct output? (in relation to regulation of the heart)
Increases or decreases frequency of nerve impulses sent out to both sympathetic and parasympathetic branches of the ANS
What is Frank Starling Law of the heart?
Within limits, the more the heart is stretched as it fills during diastole, the greater the force of contraction during systole.
What stimulates the heart to contract more forcefully? (Tip: hormones & medication)
ANS - Epinephrine/Norepinephrine
Increased Ca2+ levels in interstitial fluid
Digitalis (Medication)
What will decrease the force of cardiac contractions? (Tip: hormones etc)
Inhibition of Norepinephrine & epinephrine (sympathetic division of ANS)
Anoxia (Absence of oxygen)
Acidosis (Excess acid in body fluids)
Some Anaesthetics
Increased K+ levels in interstitial fluid
What happens to stroke volume if pressure in the pulmonary trunk and aorta is higher than normal?
The semi-lunar valves open later than normal, stroke volume decreases and more blood remains in the ventricles at the end of systole.
What are the effects of alcohol, caffeine or cigarettes on the body? i.e. NS, Heart etc
Stimulate sympathetic nervous system
Elevate heart rate and BP
Thereby increase risk of hypertension
Where does the CV centre direct output? (In relation to regulation of the heart)
Increases or decreases frequency of nerve impulses sent out to both sympathetic and parasympathetic branches of the ANS
From where does the CV Centre in the medulla oblongata receive input?
- A variety of sensory receptors
2. Higher Brain centers e.g. limbic and cerebral cortex
Which region of the brain does Nervous system regulation of the heart originate?
Cardiovascular Centre (CV) of the medulla oblongata
What are the common causes of congestive heart failure? (Tip: There are 4!)
Coronary Artery Disease
Long term high blood pressure
Myocardial Infarction
Valve Disorders
What leads to peripheral oedema in RSHF?
If the right ventricle fails, first blood backs up in the systemic blood vessels - most notable in swelling in feet and ankles.
What leads to pulmonary oedema in LSHF?
If left ventricle fails first, it can’t pump out all the blood it receives and blood backs up in the lungs
What is Congestive Heart Failure?
Heart is a failing pump.
Blood left in ventricles at end of each cycle causes Positive feedback cycle: Less effective pumping leads to even lower pumping capability
Often one side fails first
What is an artery?
A blood vessel carrying blood away from the heart
What is Ascites?
An accumulation of fluid in the peritoneal cavity.
What is atherosclerosis?
A condition where cholesterol and lipid deposits accumulate on the inner layer of the medium and large blood vessels, leading to a narrowing in these vessels
What is an athromatous plaque?
A collection of lipids and cholesterol that accumulates in large and medium sized vessels
What are Atria?
The upper chambers of the heart
What is the Atrioventricular valve?
A heart valve made up of membranous flaps that allow blood to flow in one direction only; also known as the bicuspid valve
What is the Bicuspid Valve?
Also known as the atrioventricular valve. It is a valve in the heart that contains two cusps.
What is endocardium?
The endothelial membrane that lines the inner surface of the heart
What is the inferior vena cava and where is it in the body?
Large vein that returns de-oxygenated blood from parts of the body below the diaphragm to the right atrium.
What is the Mediastinum?
A subdivision of the thoracic cavity
What is the Mitral Valve?
The left atrioventricular valve
What is the Pericardium?
A double layered sac that encloses the heart
What is the pulmonary artery?
The vessel that takes de-oxygenated blood from the right ventricle to the lungs
What is the pulmonary vein?
The vessel that returns oxygenated blood from the lungs to the right atrium
What is the semilunar valve?
A valve that prevents the backflow of blood to the ventricles after contraction
What is the superior vena cava?
The large vein that returns de-oxygenated blood superior to the diaphragm to the right atrium.
What is the Tricuspid valve?
The right atrioventricular valve
What is tunica externa?
Outer layer of blood vessels
What is tunica media?
The middle layer of blood vessels
What is tunica interna?
The inner layer of blood vessels
What is the structure and function of the tunica externa?
Composed of collagen fibres
Protects and supports blood vessels
Secures blood vessels to surrounding tissues
What type of nerve fibres supply the tunica externa?
Sympathetic nerve fibres
What type of tissue does the tunica media contain?
Smooth muscle
Elastic tissue
What tissue type is the tunica interna made up of?
Endothelia
Is the tunica interna smooth or rough?
Smooth
Why is the tunica interna smooth?
To prevent friction from the flow of blood
What are the 3 groups of arteries?
Elastic
Muscular
Arterioles
What are the vasa vasorum?
A network of blood vessels that supply the tunica externa with blood.
List characteristics of an Elastic Artery
Contain high proportion of elastic fibres in tunica media
Thick walled
Found near the heart
Large lumen
What is another name for Elastic Arteries
Conducting Arteries
List characteristics of Muscular Arteries
Medium sized
Contain more smooth muscles
Contain fewer elastic fibres
What are Muscular arteries otherwise known as?
Distributing arteries
List examples of Muscular arteries
Axillary Brachial Radial Splenic Femoral Popliteal Tibial
What is the function of arterioles?
Regulate blood flow to capillaries by altering diameter of capillaries.
What tissue are capillaries composed of?
Tunica Intima
What is a function of capillaries?
Linking arterioles to venules
Allow water, nutrients, gases and waste products in and out of blood supply
Which two sites of the body do not contain capillaries?
Cornea of the eye
Epidermis of the skin
What type of specialist cell are found in venules?
Fibroblasts
Which has a larger lumen, vein or artery?
Vein
What do veins have that arteries do not?
Bicuspid Valves
What is Blood Pressure?
The force exerted by the circulating blood on the walls of the blood vessels. It refers to Arterial blood pressure
What are the 3 main factors that regulate blood pressure?
Neuronal regulation
Hormonal regulation
Autoregulation of blood pressure
Where are the baroreceptors located?
Carotid sinus & Aortic arch
Where are the chemoreceptors located?
Aortic and carotid bodies
What is the function of the aortic and carotid bodies?
They detect changes in oxygen, carbon dioxide and hydrogen ion concentrations
List 5 hormones involved in BP regulation
Renin-angiotensin system Epinephrine (adrenalin) Norepinephrine (noradrenaline) Antidiuretic hormone Natriuretic peptide
List 5 factors that affect BP
(Not age, gender, stress, hormones, drugs
Cardiac Output Circulating Volume Peripheral Resistance Blood viscosity Hydrostatic pressure
What is the Aorta?
First major blood vessel of the arterial circulation. Emerges from the left ventricle of the heart
What is a baroreceptor?
A neuron sensing changes in fluid, air and blood pressure
What is a chemoreceptor?
A sensory receptor that detects the presence of a specific chemical
What is erythema?
A superficial reddening of the skin
