Cardiovascular System Flashcards
what is the heart
a muscular organ whose primary function is to collect and pump blood around the body
approximately how many heart beats a day
100,000 equivalent to approx 7000L/day
anatomical location of heart: region
mediastinum - the central compartment of the thoracic cavity, between the lungs
anatomical location of heart: position relative to rest of body
- posterior to sternum (breastbone)
- medial to lungs
- anterior to vertebral column
- superior to diaphragm
- within thoracic cage
- base parallel to 2nd rib
- apex (pointy bottom) on diaphragm
what are the four chambers of the heart
right atrium, right ventricle, left atrium, left ventricle
which chamber pumps blood to the body
left ventricle
which chamber pumps blood to the lungs
right ventricle
which chamber receives blood
atria (ra: the body, la: the lungs)
what are the three layers of the heart wall
endocardium (inner), myocardium (middle), epicardium (outer)
what is the pericardium
a double-layered sac that encloses the heart (fibrous & serous)
what is the function of pericardial fluid
reduces friction during heartbeats
what are the four valves of the heart
tricuspid, pulmonary semilunar, mitral (bicuspid), aortic semilunar
what do the AV valves do
prevent back flow from ventricles to atria
what do semilunar valves do
prevent backflow from arteries into ventricles
what do semilunar valves do
prevent back flow from arteries into ventricles
what re the great vessels of the heart
aorta, pulmonary trunk, pulmonary veins, superior & inferior vena cava
what are coronary (cardiac) vessels
arteries and veins that supply blood to the heart muscle itself
structure of arteries vs veins
arteries have thicker walls (more smooth muscle), veins have valves and larger lumens
what are capillaries
thin walled vessels where exchange of gases, nutrients, and waste occurs
what initiates the heartbeat
sinoatrial (SA) node - the pacemaker of the heart
order of conduction
SA node -> AV node -> bundle of his -> bundle branches -> purkinje fibres
function of AV node
slows signal before it reaches venrtricles
what is diastole
relaxation phase - ventricles fill with blood
what is systole
contraction phase - ventricles eject blood
what causes heart sounds
closing of valves (LUB = AV valves; DUB = semilunar valves)
what is blood pressure
the force of blood against artery walls
what are systolic and diastolic pressures
systolic is pressure during contraction, diastolic is pressure during relaxation
what are the components of blood
plasma, red blood cells, white blood cells, platelets
what is cardiovascular disease (CVD)
a group of disorders affecting the heart and blood vessels
what is coronary heart disease (CHD)
narrowing or blockage of coronary arteries due to atherosclerosis, reducing blood flow to the heart
what is another name for CHD
coronary artery disease (CAD)
what are the two main types of CVD
congenital (present from birth) and acquired (develops over time, often due to lifestyle)
what are the common risk factors for acquired CVD
smoking, poor diet, lack of exercise, high blood pressure, diabetes, obesity
what is the leading cause of death in the uk
CHD
how many uk death per year from CHD
over 64,000
what is Scotlands single biggest killer
CHD - around 7,000 deaths per year
which uk city has the highest rate of cardiovascular disease
glasgow
what are conduction disorders
problems with the hearts electrical system affecting rhythm and rate
what is an arrhythmia
an abnormal heart rhythm (can be too fast, too slow, or irregular)
what is a heart block
a delay or block in electrical impulses between the atria and ventricles
what is an ECG
an electrocardiogram - test that records the electrical activity of the heart
what are the main parts of an ECG wave
P wave (atrial depolarisation), QRS complex (ventricular depolarisation), T wave (ventricular repolarisation)
what can ECGs hep detect
arrhythmias, myocardial infection, heart blocks, and other conduction issues
what is angioplasty
a procedure where a balloon is used to widen narrowed or blocked arteries
what is a stent
a small mesh tube inserted into an artery to keep it open
what is a coronary bypass surgery
a procedure that uses grafts to reroute blood around a blocked artery
what is ECMO
extracorporeal membrane oxygenation - a life support technique that temporarily takes over the function of the heart and lungs
when is ECMO used
when the heart and lungs are failing but there is a chance for recovery (e.g during severe heart failure, cardiac arrest, or after surgery)
what is the cardiac cycle
one complete heartbeat - includes both contraction (systole) and relaxation (diastole) of the heart chambers
what is ventricular systole
ventricles contract and eject blood into arteries
what is ventricular diastole
ventricles relax and fill with blood from the atria
what causes the LUB heart sound
closing of the AV valves at the start of ventricular systole
what causes the DUB heart sound
closing of the semilunar valves at the start of ventricular diastole
what is atrial systole
atria contract, pushing he last bit of blood into the ventricles
what percentage of ventricular filling is passive vs active
~80% passive, ~20% from atrial contraction
what is the correct sequence of blood flow through the heart
body - > superior/inferior vena cava -> tricuspid valve -> right ventricle -> pulmonary valve -> pulmonary artery -> lungs -> pulmonary veins -> left atrium -> mitral (bicuspid valve) -> left ventricle -> aortic valve -> aorta -> body
which side of the heart deals with deoxygenated blood
right side - receives from body, sends to lungs
which side deals with oxygenated blood
left side - receives from lungs, sends to body
what is the pulmonary circuit
right side of the heart pumps deoxygenated blood to lungs and back
what is the systematic circuit
left side of the heart pumps oxygenated blood to the body and back
which circuit it higher pressure
systematic as it needs to push blood through the entire body
what are myocytes
cardiac muscle cells responsible for contractions
what are intercalated discs
connections between cardiac cells that allow fast electrical and mechanical communication
what triggers cardiac muscle contraction
calcium
what are sarcomeres
the functional units of muscle fibres where contraction occurs
what is EDV (end diastolic volume)
volume in ventricles before contraction (~120mL)
what is ESV (end systolic volume)
volume left after contraction (~50mL)
what is stroke volume (SV)
SV = EDV - ESV (~70mL normally)
what is cardiac output (CO)
CO = SV x heart rate (mL/min)
what does the sympathetic nervous system do to the heart
increases HR and contractility via norepinephrine
what does parasympathetic nervous system do
decreases HR via acetylcholine at the SA node
what is afterload
the stretch of ventricles must overcome to eject blood (arterial pressure)
what is contractility
the strength of contraction, influenced by calcium and sympathetic activity
what is preload
the stretch of ventricles before contraction, based on venous return
what is Frank-Starling’s Law
the force of contraction of a normal heart is proportional to the degree of stretching by the muscle fibres without any
intervention from the autonomic nervous system (ANS)
cardiac output is determined from which of the following factors
stroke volume and heart rate
what’s an ECG
electrocardiogram
what are
oxygenated blood flows from the heart through systematic circulation in which order
arteries, arterioles, capillaries, venules, veins
arteries are structurally different from veins in which way
they have thicker and stretchier walls to accommodate high pressure and they lack valves
the purpose of valves is to
ensure unidirectional blood flow
the point of highest blood pressure is - and the point of lowest blood pressure is - pressure
systolic, diastolic
which arteries supply the brain
carotid
what arteries supply the upper limbs
axillary
what arteries supply the lower limbs
femoral
the superior and inferior mesenteric arteries primarily supply
the intestines
the kidneys are supplied by…
renal arteries
the celiac trunk supplies
the tibial arteries supply the
the pancreaticonduodenal arteries support the
the major veins draining the head are the
jugular veins
cephalic vein
brachiocephalic veins
facial veins
the iliac veins are located in which area of the body
pelvic region
first and last step of the systematic circulation
blood is pumped from the left ventricle into the aorta, blood drains from the superior and inferior venae cave into the right atrium
arteries carry blood…
away from heart
capillaries role is to…
exchange oxygen, CO2, nutrients and waste
veins carry blood…
back to hear
what’s the largest artery in the body
aorta: carries oxygenated blood from heart to body
what’s the largest vein(s) in the body
superior and inferior vena cava: carries deoxygenated blood back to the heart from the body
