Cardiovascular System Flashcards
Heart position
Mediastinum - behind the sternum and angled slightly left
Heart - pericardium
Fibrous pericardium
Serous pericardium - parietal (outer layer and visceral (inner) layer
Function of the pericardium
Protect the heart
Anchor the heart into position
Prevent over filling
Friction free environment
Epicardium
Outer layer - visceral pericardium
Supports blood vessels and nerves
Myocardium
Middle layer
Made of cardiac muscle
Endocardium
Inner layer
Made of squamous epithelium - smooth, friction free environment for blood flow
Structure of the heart
Four chambers - 2 atria and 2 ventricles
Two sets of valves - atrioventricular (tricuspid and bicuspid) and semilunar
Septum
Right to lungs
Left to bods
Valves of the heart
Prevent backflow of blood
Chordae tendineae attaches to the papillary muscle and anchor the valves into position - stop inverting
Open and close due to pressure changes
Blood vessels - Tunica externa layer
Outer layer
Loose, thick layer of connective tissue
Elastic and collagen fibres
Anchor the vessels to surrounding structures
Protection
Blood vessels - tunica media layer
Middle layer
Muscular and connective tissue
Smooth muscle cels
Vasoconstriction and vasodilation
Elastic fibres - recoil after stretch
Blood vessels - tunica intima layer
Innermost layer
Epithelial lining forming perimeter of lumen
Internal elastic lamina - elastic fibres, recoil after stretch
Lamina propria - outer layer of elastic connective tissue
Basement membrane - collagen fibres, firm supportive base, regulates molecular movement, tissue repair
Endothelium - squamous, permeate, regulate diffusion
Elastic/conducting arteries
Thick walled
Close to the heart
Elastic tissues - expansion and contraction causing blood to flow smoothly
Muscular arteries
Smaller
Branch from, elastic arteries
Distribute blood top body
More muscular tunica media - control blood flow
Arterioles
Smooth muscle (media) around endothelium
Collagen fibres
Regulate blood flow to capillaries
Vasodilation and vasoconstriction
Capillaries
Smallest
Thin walled
Tunica intima
Access to all the cells
Slower blood flow for to allow exchange
Larger SA
Continuous capillaries
Least permeable
Most common
E.g. skin, muscle
Fenestrated capillaries
Large fenestrations (pores) - increase permeability
Special locations
E.g. kidney, small intestine
Sinusoidal capillaries
Most permeable
Special locations
E.g. liver, bone marrow, spleen
Precapillary sphincters
Redirect blood flow depending on body needs
Open - through true capillaries
Closed - through metarteriole
Veins and venules
Venules - capillaries joining together
Veins - venules joining together, lower BP, walls (tunicas) much thinner
Return of blood to the heart
Pressure
Valves
Skeletal muscle pump
Respiratory pump
Coronary arteries - left
Two branches
Anterior interventricular artery - left anterior descending artery
Circumflex artery
Coronary arteries - right
Two branches
Right marginal artery
Posterior interventricular artery
Coronary veins
Venus blood collected by cardiac veins
Join together to form coronary sinus - empties into the right atrium, three large tributaries; great cardiac vein, middle cardiac vein, small cardiac vein
Anterior cardiac veins empty into right atrium
Pulse
Pressure waves felt in an artery that lies close to the surface of the body
Result from the left ventricle contracting
Blood pressure
Pressure exerted by the blood on the walls of a blood vessel
mmHg
Sphygmomanometer
Systolic blood pressure (SBP)
True highest pressure
Measured when the left ventricle is contracting and expelling blood into the aorta
Diastolic blood pressure (DBP)
Lowest pressure
Measured when the left ventricle is relaxing and blood is flowing into the peripheral blood vessels
Pulse pressure (PP)
The difference between systolic and diastolic blood pressure
Felt in arteries
Indication of health of blood vessels
Over 60mmHg = not healthy
Mean arterial pressure (MAP)
The pressure that propels the blood through the tissue
Equivalent to the DBP + one third of PP
What determines blood pressure
Cardiac output
Peripheral resistance - diameter and length
Blood volume
Blood viscosity
Vasodilation
Vasoconstriction
Vascular tone
Control of blood pressure - low
Stimulus - low BP
Baroreceptors inhibited
Stilmulates cardioaccelerator centre and vasomotor centre
Vasoconstriction - increase restriction
Increase sympathetic impulse to heart - increase HR, contractility and CO
Control of blood pressure - high
Stimulus - high BP
Baroreceptors stimulated
Stimulate cardioinhibitory centre and inhibit vasomotor centre
Vasodilation - decrease restriction
Decrease sympathetic impulses to heart - decrease HR, contractility, CO
Marley’s law
Inverse relationship between blood and heart
If BP too high, the heart rate will decrease
If BP too low, the heart rate will increase
Bainbridge reflex
Blood returning to the heart enters the right atrium
Stretch receptors in right atrium detect atrial filling
Initiate reflex
Results in increase heart rate - clear the extra blood
Frank starling’s law
More blood entering the ventricles from atria
Greater stretch = greater force of ventricle contraction = greater SV
Force of ventricular contraction is determined by the length of the cardiac muscle fibres
Stroke volume
Amount of blood ejected from the ventricle during one contraction
End diastolic volume
Amount of blood in the left ventricle at the end of diastole
End systolic volume
Amount of blood in the ventricle at the end of systole
At rest not all the blood in the heart is pumped out
Preload
The degree to which the ventricular muscle is stretched just before contracting
After load
The pressure the ventricles must overcome to push the blood through the semilunar valves as the ventricles contract
Around 80mmHg for left and 8mmHg for right
Long-term changes in blood pressure
The renin-angiotensin-aldosterone system - initiated by decreased blood flow to the kidney, resulting in an increase on blood volume and vasoconstriction. This results to increased blood pressure
Increased CO2 concentration
CO2 + H2O > H2CO3 > HCO3- + H+
Carbon dioxide plus water forms carbonic acid
Dissociates into bicarbonate (alkali) and hydrogen ions
At lungs re associates so C)2 and water vapour can be exhaled
During exercise
Increase HR and SV = increase Q = increase BP - meet demands of muscles
Increased muscle activity detected by proprioceptors = increase HR and SV = increase Q and BP
Wiggers’ diagram
- Pressure left atrium > left ventricle = BF to left ventricle
- Left ventricle contracts, pressure builds, bicuspid closes
- Pressure left ventricle > aorta, semilunar opens
- Ventricles relax, pressure drops, pressure aorta > ventricle, semilunar closes
- Ventricle pressure drops below atria, bicuspid opens, ventricles fills
Action potential of contractile cardiac muscle cells
Depolarisation - atria contract, electrical stimulation
Plateau phase - Ca2+ influx, Ca2+ causes muscle contraction
Repolariation - return to resting phase
Refractory period - prevents summation, allows heart to fill
Depolarisation
The stimulus
Causes a response in the muscle cell
Contraction of the cell
Repolarisation
Depolarised cell returning to the resting position and getting ready for next contraction
P wave
Sino atrial node sends out an impulse actress atria
Atria contract
PR interval
Impulse delayed at atrioventricular node
QRS complex
Impulse passed on to ventricles
Ventricles contract
S-T segment
Interval between ventricular depolarisation and repolarisation
T wave
Ventricular repolarisation begins
Ventricles get ready for the next contraction
Heart rate control
Sino atrial node initiates firing of 100b.min-1
Regulated by autonomic nervous system
Sympathetic nerves (accelerator nerve) increase HR and force of contraction
Parasympathetic nerves (vagus nerve) decrease HR
Conduction of the heart
Sino atrial node
Atrioventricular node
Bundle of His
Purkinje fibres
Arrhythmia
Abnormal heart rhythm
Ectopic focus - site that generates an ectopic beat
Tachychardia - >100b.min-1
Bradycardia - <60b.min-1
Myocardial infarction
Insufficient blood flow to the heart muscle from narrowing of coronary artery
May cause chest pain
Hypertension
High blood pressure
140/90 mmHg or more in the <80
150/90 mmHg or more >80
Risk factor of cardiovascular disease
Hypotension
Low blood pressure
A drop in systolic blood pressure of 20 mmHg or more
A drop to below 100 mmHg on standing even if it drop is less than 20 mmHg
A drop in diastolic blood pressure of 10 mmHg is considered positive with symptoms
Congenital heart disease (CHD)
General term for a range of birth defects that affect how the normal heart works
Septal defects
ASD
VSD
Valves defers
CoA
Congenital heart disease (CHD) symptoms
Blue tinge to skin or lips (cyanosis)
Rapid breathing and heartbeat
Swelling in legs, tummy, around eyes, hands, ankles or feet
Shortness of breath in babies during feeding
Extreme tiredness and fatigue
Fainting during exercise
Congenital heart disease (CHD) treatments
Surgical correction of defect
Valve or reconnection of the crossed veins
Arteries or compartments “pluming”
Valve replacement
Coronary heart disease (CHD) cause
Atherosclerosis - a plaque build up in the arteries around the heart
Coronary heart disease (CHD) symptoms
Chest pain (angina); arm, neck, back,chest,jaw
Shortness of breath
Pain throughout the body
Feeling faint
Feeling sick (nausea)
Risk factors for developing atherosclerosis
Smoking
High blood pressure (hypertension)
High cholesterol
High levels of lipoprotein (a)
Sedentary lifestyle
Diabetes
Obesity
Family history of CHD
Acute coronary syndrome (ACS) and MI
ST-segment elevation myocardial infraction (STEMI)
Non-ST segment elevation myocardial infarction (NSTEMI)
Unstable angina
Treatments for CHD and ACS
Angioplasty - stenting
Glyceryl trinitrate (GTN)
Coronary artery bypass grafting (CABG)
Heart failure
Caused by a structural and/or functional abnormality that produces raised intracadiac pressure and/or inadequate cardiac output at rest and/or at exercise
Long-term condition, gradually worse over time
Heart failure symptoms
Breathlessness on exertion or rest
Fatigue or feeling tired most of the time
Finding exercise exhaustion
Feeling lightheaded, dizzy or fainting
Oedema - swollen ankles and legs
Heart failure causes
Coronary artery disease
Hypertension
Cardiomyopathy
Familial
Infective
Immune-mediated
Toxins - alcohol or cocaine
Pregnancy
Sarcoidosis
Amyloidosis
Haemochromatosis
Connective tissue disease
Congenital heart disease
Arrhythmia
End-stage chronic kidney disease
Liver failure
Obesity
Heart failure with preserved ejection fraction (HF-PEF)
People who have symptoms of heart failure, cardiac structure or function abnormalities, and/or raised levels of natriuretic peptides with a preserved LVEF >50%
Heart failure with mildly reduced ejection fraction (HFmrEF)
People with a LVEF between 41-49%
Heart failure with reduced ejection fraction (HFrEF)
A reduced LVEF of <40%
Heart failure treatments - medical management
Stop any medication that could be impacting on the heart - chemotherapy
Diuretics - frusemide
Antiplatelet treatment - reduces platelets, thinning the blood
Antihypertensives - angiotensin-converting enzyme (ACE) inhibitor
Beta blockers
Heart failure treatments - holistic management
Lifestyle changes - healthy diet
Exercise regularly
Cardiac rehabilitation
Smoking cessation
Peripheral vascular disease (PVD)
Many vascular diseases
Peripheral arterial disease (PAD)
Deep vein thrombosis (DVT)
Peripheral arterial disease (PAD) symptoms
Intermittent claudication
Hair loss on legs and feet
Numbness or weakness in the legs
Brittle, slow-growing toenails
Ulcers on feet and legs
Discolouration on the skin paler than usual or blue
Shiny skin
Erectile dysfunction in men
Muscle atrophy
Peripheral arterial disease (PAD) treatments - medication
Statins - reduce the production of LDL cholesterol by your liver
Antihypertensives - reduce blood pressure
Naftidrofuryl oxalate - reduced claudication
Antiplatelet treatment - reduces platelets thinning the blood
Peripheral arterial disease (PAD) treatments - lifestyle changes
Weight reduction of obese - medical Rx
Diet change
Reduce alcohol intake
Smoking cessation
Exercise
Deep vein thrombosis (DVT) symptoms
Throbbing pain in one leg
Swelling in one leg
Warm skin around the painful area
Red or darkened skin around the painful area
Swollen veins that are hard or sore when you touch them
Risk factors for DVTs
Over 60
Obese
Smoker
Previous DVT
Contraceptive pill or HRT
Cancer or heart failure
Varicose veins
Post surgical patients
Bed bound patients
Long journey
Pregnant or had a baby in the pervious 6 weeks
Dehydrated
Risks of PAD and DVT
Piece of atherosclerosis breaks off the artery a blood clot will develop
Blood clot can travel around the body
If it travels/develops in the coronary artery it can trigger a heart attack
If it travels/develops in the arteries supplying the brain it can cause a stroke
If it travels/develops in the lungs it will cause a pulmonary emboli (PE)
Symptoms of pulmonary emboli
Difficulty breathing that comes on suddenly
Chest pain that’s worse when you breath in
Coughing up blood
Treatment for PE and DVT
Anticoagulation - physiotherapy can start after treatment dose is given
Mobility
Exercise
Lifestyle advice
