Week 2 (parts 1 and 2) Flashcards
WEEK 2 pt1
Cardiac anatomy and physiology
what is the function of blood
transport of oxygen, metabolic waste products, hormones; regulation of body temp, pH in body tissues, Maintaining adequate fluid volumes; protection - preventing blood loss via clotting, preventing infection
what are the main components of blood
plasma,RBCs, WBCs, platelets
where is the heart located
behind the sternum, 1/3 lies to the right of the midline, 2/3 lies to the left of the midline
what is the function of the atria
receiving chambers for blood
what is the function of ventricles
pumping chambers for the blood
what is pericardium
double walled sac surrounding the heart
what is the outer layer of pericardium
fibrous pericardium - made of fibrous connective tissue, protects heart, prevents overfilling, anchors heart to surrounding structures
what are the inner layers of Pericardium
Serous pericardium:
- Parietal pericardium lines the fibrous
pericardium
- Visceral pericardium fused to external layer of the heart wall (AKA epicardium)
- Pericardial fluid is in between parietal and visceral pericardium (pericardial cavity)
lubricates and creates frictionless environment
what are the 3 layers of the walls of the heart
Epicardium (outer layer), Myocardium (middle layer), Endocardium (thin layer of endothelium)
what are the key facts about myocardium
thickest layer of the wall of the heart, the layer that contracts, composed of cardiac muscle fibres arranged in spiral and loops, separate systems for atria and ventricles
what are the valves of the heart
Atrioventricular valves:
Tricuspid (right), Bicuspid (left)
Semilunar valves:
Pulmonary (right)
Aortic (left)
what is the pathway of blood through the heart
Right Side:
Pulmonary Circulation:
- R atrium receives deoxygenated blood from the body via the superior and inferior vena cava
- Blood passes through the right tricuspid valve into the right ventricle
- Then passes through the pulmonary valve into the pulmonary artery
- Destination – lungs
Left Side:
Systemic circulation
- L atrium receives oxygenated blood from the lungs via the pulmonary veins
- Blood then passes through mitral valve into the L ventricle
- Though the aortic valve into the aorta
- Destination – the body
what is coronary circulation
Coronary Circulation:
- Oxygenated blood supply to the heart supplied by coronary arteries
- Right and left coronary arteries arise from the base of the aorta
- Coronary arteries are superficial – located in epicardium
- Send branches deeper into the myocardium
- Blood flow to the myocardium occurs when the heart is relaxed – during a contraction the blood vessels in the myocardium are compressed
- Coronary veins return deoxygenated blood to the right atrium via the coronary sinus
what is systole
heart contracts
what is Diastole
heart relaxes
what happens in early diastole
- Whole heart relaxed
- Pulmonary and aortic valves shut
- AV valves (tricuspid and bicuspid/mitral) open
- Blood flowing passively from great veins through atria to ventricles
what happens during atrial systole
- Atria contract forcing blood into the ventricles
- Atria then relax
what happens during ventricular systole: isovolumetric contraction
- Ventricles contract
- Increase ventricular pressure
- AV valves now close
- Aortic and pulmonary valves still closed – this contraction does not bring about any change in volume
what happens during ventricular systole: ventricular ejection
- Ventricular pressure continues to rise
- Aortic and pulmonary valves forced open
- Blood rapidly ejected into the aorta (L) and pulmonary artery (R)
- While the ventricles are in systole, atria are in diastole and filling with blood
what happens during ventricular diastole: isovolumetric relaxation
- Ventricles relax and ventricular pressure drops
- Blood in aorta and pulmonary artery starts to flow back towards heart = aortic and pulmonary valves shut
what are the specialised conduction fibres in the heart
- Sinoatrial node (pacemaker)
- Atrioventricular node (AV node)
- Atrioventricular bundle of His
- Purkinje fibres
Contraction imitated at the SA node in the R atrium, Impulse spreads through both atria to the AV node, Passes to the bundle of His, Finally, to the Purkinje fibres
what is the function of the SA node
Causes depolarisation and contraction of both atria (atrial systole)
what is the function of the AV node
- Slows impulse down
- Allows time for atrial contraction and ventricular filling
what is the function of the Bundle of His and Purkinje Fibres
- Causes depolarisation and contraction of both ventricles (ventricular systole)
WEEK 2 pt 1
Cardiac anatomy and Physiology
what are the functions of blood
transport: oxygen, metabolic waste products, hormones
Regulation of: body temp, pH in body tissues, maintaining adequate liquid volume
Protection: preventing blood loss via clotting and preventing infection
what are the main components of the blood
Plasma, RBCs, WBCs, Platelets
where/ how is the heart located in the chest
behind the sternum, 1/3 lies to the right of the midline, 2/3 lies to the left of the midline
what is the double membrane that surrounds the heart
Pericardium
how many chambers does the heart have
2 atria (receiving chambers) and 2 ventricles (Pumping chambers)
what is Pericardium
double walled sac surrounding the heart
Fibrous pericardium is the outer layer
Made of tough fibrous connective tissue
Protects heart, prevents overfilling, anchors heart to surrounding structures (including diaphragm via the central tendon)
Serous pericardium is the inner layers:
Parietal pericardium lines the fibrous pericardium
Visceral pericardium fused to external layer of the heart wall (AKA epicardium)
Pericardial fluid in between parietal and visceral pericardium – pericardial cavity – lubricates and creates frictionless environment
what are the layers of the walls of the heart
Epicardium (AKA visceral pericardium)– outer layer a thin layer of external membrane
Myocardium – middle layer of cardiac muscle
Endocardium – thin layer of endothelium
What is the structure of myocardium
Thickest layer of the wall of the heart
This is the layer that contracts
Composed of cardiac muscle fibres arranged in spirals and loops
Separate systems for atria and ventricles
Cardiac muscle cells (cardiomyocytes) are specialised “excitable cells”
what is the difference between the walls of the atria and walls of the ventricles and why
Atria smaller and thinner walls than ventricles
only have to pump blood into the adjoining ventricle
Ventricles pump blood
To the lungs (right ventricle)
Around the body (left ventricle)
Left ventricle thicker walled than the right ventricle
what are the two types of valves that separate the atria and ventricles
Atrioventricular Valves:
* Tricuspid valve on right
* Bicuspid valve on left
Semilunar Valves:
* Pulmonary Valve on right
* Aortic valve on left
how does blood flow through the right side of the heart
Pulmonary circulation (heart-lungs)
R atrium receives deoxygenated blood from the body via the superior and inferior vena cava
Blood passes through the right tricuspid valve into the right ventricle
Then passes through the pulmonary valve into the pulmonary artery
Destination – lungs
how does blood flow through the right side of the heart
Systemic circulation (heart-body)
L atrium receives oxygenated blood from the lungs via the pulmonary veins
Blood then passes through mitral valve into the L ventricle
Though the aortic valve into the aorta
Destination – the body
what is coronary circulation
Oxygenated blood supply to the heart supplied by coronary arteries
Right and left coronary arteries arise from the base of the aorta
Coronary arteries are superficial – located in epicardium
Send branches deeper into the myocardium
Blood flow to the myocardium occurs when the heart is relaxed – during a contraction the blood vessels in the myocardium are compressed
Coronary veins return deoxygenated blood to the right atrium via the coronary sinus
what is systole
when the heart contracts
what is diastole
when the heart relaxes
what is the cardiac cycle
mechanical events which occur with the flow of blood through the heart in one heartbeat
Mechanical events are preceded by electrical activity
what happens during early diastole
Whole heart relaxed
Pulmonary and aortic valves shut
AV valves (tricuspid and bicuspid/mitral) open
Blood flowing passively from great veins through atria to ventricles
what happens during atrial systole
Atria contract forcing blood into the ventricles
Atria then relax
what happens during ventricular systole (isovolumetric contraction)
Ventricles contract
Increase ventricular pressure
AV valves now close
Aortic and pulmonary valves still closed – this contraction does not bring about any change in volume
what happens during ventricular systole (ventricular ejection)
Ventricular pressure continues to rise
Aortic and pulmonary valves forced open
Blood rapidly ejected into the aorta (L) and pulmonary artery (R)
While the ventricles are in systole, atria are in diastole and filling with blood
what happens during ventricular diastole (isvolumetric relaxation)
Ventricles relax and ventricular pressure drops
Blood in aorta and pulmonary artery starts to flow back towards heart = aortic and pulmonary valves shut
what are the specialised conduction fibres of the heart
Sinoatrial node (pacemaker)
Atrioventricular node (AV node)
Atrioventricular bundle of His
Purkinje fibres
Contraction imitated at the SA node in the R atrium
Impulse spreads through both atria to the AV node
Passes to the bundle of His
Finally, to the Purkinje fibres
what is the function of the SA node
Causes depolarisation and contraction of both atria (atrial systole)
what is the function of the AV node
Slows impulse down
Allows time for atrial contraction and ventricular filling
what is the function of the Bundle of His and Purkinje Fibres
Causes depolarisation and contraction of both ventricles (ventricular systole)
what is depolarization of the heart
At rest, cardiac calls are considered polarised i.e. no electrical activity takes place
When an electrical impulse is generated it causes depolarisation which results in
an action potential being created
Action potentials are related to ionic movement in the cell*
Depolarization with corresponding contraction of myocardial muscle moves as a wave through the heart
Repolarisation results in the return of the ions to their previous resting state – corresponds with relaxation of the myocardial muscle
Depolarization and repolarization are electrical activities which cause muscular activity in the heart
how does the autonomic nervous system regulate the heart
Normal adult heart rate (HR) 50-100 beats per minute
ANS regulates the electrical conductivity of the heart
Adjusts HR in response to various stimuli
Increases HR by releasing catecholamines, adrenaline and noradrenaline
Decreases HR by releasing acetylcholine
what is a normal adult blood pressure during systole and diastole
Systolic / Diastolic
95-140 / 60-90 mmHg
what is blood pressure
Pressure exerted by blood against the inner wall of an artery
BP = SV x HR x TPR
what is heart rate
beats per minute
what is stroke volume
volume of blood ejected from ventricles per contraction
what is cardiac output
volume of blood ejected from ventricles in 1 minute (SV x HR)
what is total peripheral resistance (TPR)
friction encountered by blood as it passes through a peripheral artery
how is blood pressure regulated
BP regulated by baroreceptors located in pressure receptor zones:
High pressure zones e.g. aortic arch
Low pressure zones e.g. venae cava, atria, pulmonary veins
Baroreceptors send signals to the medulla (in brainstem) where autonomic nervous system stimulation leads to adjustments
Force of contraction
HR
Renal system – long term regulation of BP via altering blood volume
what are blood vessels made up of
Arteries
Arterioles
Capillaries
Venules
Veins
Arteries carry blood away from the heart
They branch to as they form smaller and smaller divisions reaching their smallest divisions – arterioles
Capillaries have contact with tissue cells
Veins carry blood towards the heart
Venules (the smallest veins) join into successively larger vessels approaching the heart
which blood vessel is the right atrium supplied by
vena cava
what is the function of the right ventricle
pumps blood to pulmonary arteries
which blood vessel is the left atrium supplied by
pulmonary veins
what is the function of the left ventricle
pumps blood to aorta
what are the three layers of most blood vessels
Tunica intima – inner layer, in contact with the blood
Tunica media – smooth muscle and elastin
Tunica externa/adventitia – outer layer made of collagen
what are the blood vessels involved in moving blood away from the heart
Elastic arteries
Thick-walled elastic arteries near heart and aorta
Largest diameter 2.5cm – 1cm
Large lumens = low resistance
Blood flows continuously (not stop-start) because the walls expand and recoil as the heart ejects blood
Muscular arteries
Deliver blood to specific organs
Able to vasoconstrict as have more smooth muscle
Arterioles
Lumen <0.3mm
Blood flow to capillary bed determined by arteriolar diameter – which can change due to neural, hormonal and local chemical influences
what are the 2 types of capiliaries
Metarteriole – thoroughfare channel connecting arteriole to venule (vascular shunt)
True capillaries – actual exchange vessels. 10-100 per capillary bed
what is capillary exchange
Exchange between blood and surrounding tissues across the capillary walls:
Passive diffusion of substances down concentration gradients- nutrients, O2, CO2, metabolic wastes etc
Bulk Flow – where filtered blood plasma moves in and out of tissues via pressure and osmotic changes
Bulk flow plays an important role in regulating blood fluid volume
Any imbalance between the amount filtered and the amount reabsorbed is corrected by the lymphatic system
what are the 2 subdivisions of veins
Venules:
Capillaries unite to form venules
Postcapilliary venules are porous (like capillaries) – fluid and white blood cells can move through their walls e.g. inflammation
Veins:
3 layers in their walls, but thinner walls and smaller lumens than arteries
Able to accommodate large volume of blood
Have valves (venous valves) to prevent back flow of blood – prevalent in the veins of the limbs
WEEK 2 pt 2
Cardiac Pathologies
what are the modifiable risk factors of cardiac disease
Smoking
Unhealthy diet
Obesity
Physical inactivity
Hypertension
Associated conditions i.e diabetes
Dyslipidaemia
Social isolation
Depression
Stress
what are the non-modifiable risks of cardiac disease
Age
Sex M>F
Family history
Poor socioeconomic status
Indigenous
Inflammation from diseases, such as arthritis, lupus or infections, or inflammation of unknown cause
what are the global risk factors of heart and circulatory disease
hypertension, dietary risks, high LDL cholesterol, air pollution, tobacco, diabetes, obesity, renal failure
