circulatory system Flashcards
what type of circulatory system is the human circulatory system?
closed
name of the 4 chambers of the heart
left / right atrium
left / right ventricle
what is the purpose of the cardiovascular system?
Transports nutrients such as glucose and oxygen, and hormones around cells of the body and removing waste products such as carbon dioxide and urea from cells of our body.
closed circulatory system definition
Blood flows through blood vessels (arteries, veins and capillaries) with the heart pushing the blood around the body.
structure of arteries
hick-walled, muscular blood vessels with elastic fibers withstand the high pressure of blood being pumped from the heart
function of arteries
Arteries carry oxygenated blood (except for the pulmonary artery, which carries deoxygenated blood) away from the heart to various body tissues and organs.
biggest artery in the body
aorta
what do arteries branch into
arterioles
structure of arterioles
smaller than arteries
thinner walls
less elastic tissue
function of arterioles
Arterioles regulate blood flow and blood pressure by constricting or dilating, which can control the amount of blood that reaches specific tissues or organs.
structure of capillaries
smallest and thinnest blood vessels in the body
made of a single layer of endothelial cells (easy gas exchange)
capillaries function
- facilitate the exchange of substances (e.g., oxygen, nutrients, carbon dioxide) between the bloodstream and surrounding tissues.
- connect the artioles to the venules
how is endothelium adapted to its job role
permable to diffuse quickly
venules structure
smaller than veins but bigger than capillaries and have thinner walls compared to arteries
function of venules
collect blood from capillaries and merge to form larger veins to transport blood back towards the heart.
structure of veins
thinner walls than arteries and a larger lumen (internal space). They contain less elastic tissue and are less muscular.
function of the veins
carry deoxygenated blood (except for the pulmonary vein, which carries oxygenated blood) from tissues and organs back to the heart, completing the circulatory loop.
what do valves do in veins
prevent backward flow of blood
what do arteriloes do
regulate blood floww
what do venules do
venules collect blood from capillaries
what do capillaries do
capillaries facilitate nutrient and gas exchange
what do arteries do
Arteries carry oxygenated blood away from the heart
contracted heart is called
systole
relaxed heart is called
diastole
what does the heart do
pumps the blood in order to move nutrients through the blood vessels to nourish and remove metabloic waste from the body
innermost layer of the heart
endocardium
middle layer of the heart
myocadrium
outer layer of the heart
pericardium
what is blood
liquid made of 55% plasma and 45% blood cells
scientific name for red blood cells
erythocytes
scientific name for white blood cells
leukocytes
scientific name for platelets
thrombocytes
what is diastole
relaxation phase
minimum arterial pressure
what happens during diastole
the heart chambers (atria + ventricles) are relaxed and fill with blood from the body and lungs
pressures in heart during diastole
lower pressure in heart chambers
what is systole
contraction phase
maximum arterial pressure
what happens during systole
he heart muscle contracts and pushes the blood out of the heart and into the large blood vessels of the circulatory system. From here, the blood goes to all of the organs and tissues of the body.
how does the pressure change in the heart
Contraction of the myocardium
what happens during atrial systole
The heart is full of blood and the ventricles are relaxed
Both the atria contract and blood passes down to the ventricles
The atrio-ventricular valves open due to blood pressure
70% of the blood flows passively down to the ventricles so the atria do not have to contract a great amount.
what is ventricular systole
atria relax.
ventricle walls contract, forcing the blood out
shuts tricuspid + bicuspid valves - lub
diastole (4)
ventricles relax
ventricles have lower pressure than arteries
Blood under high pressure in the arteries causes the semi lunar valves to shut.
all the muscle in the heart relaxes.
atrial systole definition summary on graph
Ventricular pressure increases due to passive filling
ventricular systole definition summary on graph
Ventricular pressure increases due to contraction
diastole definition summary on graph
Ventricular pressure decreases as ventricles relax
Which 2 parts of the heart experience the highest pressure
Aorta and left ventricle
why do the aorta and left ventricle have the highest pressure?
Left ventricle has thickest muscle wall in heart, creates greatest pressure, left ventricle empties to aorta
Why does the atrial pressure increase just before the ventricle pressure increases
Atria pushing blood into ventricle
Why is the atrial pressure always lower than the ventricular pressure
Atria are much small than ventricles and their muscle walls are thinner
Why does the ventricle pressure fall more than the aortic pressure
Aortic semilunar valve closes preventing back flow and pressure drop
why does the atrial pressure slowly increase as the ventricle pressure drops
Atria are filling with blood
What does diastole mean
Point of minimum aortic pressure
What does systole mean
Point of maximum aortic pressure
the five types of blood vessel that blood passes through on its way from the heart
Arteries, arterioles, capillaries, venules and veins
what does myogenic / myogenisis mean?
Myogenesis means the hearts rhythm is self generated
how is the heart myogenic
Neurones act on the heart to speed it up or slow it down (neurogenesis)
defentiton of how the heart is myogenic
heart is a muscular organ
contractions are initiated by electrical impulses
impulses are generated within the heart itself, making it a myogenic organ.
where does electrical impulses start in the heart?
SA node
1st step of electrical impulses in the heart
1 - starts in sa node
pacemaker generates waves of signals to contract
2nd step of electrical impulses in the heart
spreads across atria - delay at AV node
3rd step of electrical impulses in the heart
Signals move down the Bundle of His
Signals pass to heart apex
4th step of electrical impulses in the heart
Signals at bottom of apex spread up through ventricles
goes through purkinjie fibres
where is the SA node
right atria
where is AV node
middle between the atrias
what do bundle branches do
carry electrical impulses
where is the heart apex
bottom of heart
where are the purkinjie fibres
the muscle outside of the ventricles / atrium
whats the SA node known as
natural pacemaker
what does the bundle of his do
contracts muscles in the center of the heart
what do the purkinjie fibres do
make the ventricles contract
myogenic defintion
has its own electrical impulses
what does the AV do
insulates the heart
prevents direct transfer of wave of excitation to ventricles
what is the name of the things that change our heart rate
external factors
some examples of external factors
anxiety
hormones
ageing
temperature
infection
exercise
what does tachycardia mean?
high heart beat rate
what does bradycardia mean
low bpm
SA node in full terms
Sino-Atrial node
AV node in full terms
Atrio-Ventricular node
defenition of blood pressure
pressure excerted by circulating blood upon the walls of blood vessels
fancy name for blood pressure machine
sphygmometer
how does blood pressure machine work
restricts blood flow (brachial artery) then gradually deflates and blood flows - systolic and disystolic measurement
how is blood pressure measured
mmHg
millimeters of mercury
low blood pressure
under 90
under 60
normal blood pressure
under 120
under 80
at risk of prehypertension blood pressure rate
120-139
80-89
high blood pressure rate
140 or higher
90 or higher
limitations of blood pressure cuff
position
patient movement
cardiac arythmia
rapid pressure change
severe shock
heart rate
things that can change blood pressure
salt intake
smoking - vasoconstriction
atherosclerosis
loss of elasticity with age
adrenaline
diet - fatty deposits in the bv
what are the 3 things in blood
plasma
buffy coat
erythrocytes
whats in a buffy coat of blood
leukocytes + thrombocytes
percentage of plasma in blood
55%
percentage of buffy coat layer in blood
<1%
percentage of erythrocytes in blood
45%
leukoyctes common name
white blood cells
erythrocytes common name
red blood cells
thrombocytes common name
platelets
leukocytes structure
lacks haemoglobin
have a nucleus
leukocytes function
defend the body
leukoyctes sub types
basophil
eosinophil
neutrophil
monocyte
lymphocytes
specialized features of erythrocytes
flattened, biconcave, disc shape for efficient gas exchange
features of erythrocytes
large amount of haemoglobin - for transporting oxygen
no nucleus or organelles - maximises space for haemoglobin
diameter 6 - 8 micrometers larger than capillary diametr - slows blood flow to enable diffusion
problem with having a lack of nucleus
cannot divide, must be continusoly replaced
120 days lifespan
thrombocytes function
responsible for blood clotting
thrombocytes structure
no nucleus
how are thrombocytes made?
fragrements of cell cytoplasm from a larger cell called the megakaryocyte
3 ways that carbon dioxide is transported
dissolved in the blood plasma 10%
carbaminohaemoglobin in erythrocytes - 30%
biocarbonate in erythrocytes - 60%
travel of oxygen from
transported by haemoglobin the red pigment in erythrocytes
oxygen diffuses into the blood at the lungs and binds to the haemoglobin proteins
oxygen disassociates from haemoglobin in the tissues and diffuses into the tissues
electrical impulses acronym
SADBAP – Sino atrial node, atrial ventricular node, delay (allows atria to empty), bundle of His, apex, pukinje fibres
what do A and B groups refer to
one of 2 carbohydrate antigens found on the surface of red blood cells
where are antibodies found?
blood plasma
how can you figure out a blood group?
using antibodies that bind A or B antigens of red blood cells
A blood group
antigen type?
A
A blood group
serum ( plasma) antibodies
anti B
A blood group
can receive
A, O
A blood group
donate
A, AB
B blood group
antigen type?
B
B blood group
Serum ( Plasma) Antibodies
anti A
B blood group
receive
B, O
B blood group
donate
B, AB
AB blood group
antigen type
A+B
AB blood group
Serum ( Plasma) Antibodies
none
AB blood group
receive
AB, A, B, O
AB blood group
donate
AB
O blood group
antigen type
none
O blood group
serum (plasma) antibodies
anti A
anti B
O blood group
receive
O
O blood group
donate
AB, A, B, O
definition of agglutination
clumping of erythrocytes that occurs when different blood types are mixed together
rhesus blood group
either have it = +
or dont = -
what antigens does A- have?
A antigen
what antigens does A+ have?
A antigen
Rh antigen
what antigens does B- have?
B antigen
what antigens does B+ have?
B antigen
Rh antigen
How does an ecg graff look like?
Zig zag
how would a blood pressure graph look like
curve
what can ecgs help detect?
arythmias
cornoary heart disease
heart attacks
cardiomyopathy
what are arythmias
heart beating too quickly, slowly or irregular
what is coronary heart disease
where the blood supply is blocked or interuppted by a build up of fatty substances
what is a heart attack
supply of blood suddenly becomes blocked
what is cardiomyopathy
heart walls become thickened
what are the 3 types of ecgs
ambulatory
resting
stress/ exercise
what is a resting ecg
lying down
what is a ambulatory ecg
electrodes connected to small portable device on waist
what is a stress / excersise ecg
when doing streneous activities
how many electodes are placed (ecg)
10
self adhesive dots - single electrical contacts
where are the electrodes placed?
6 on chest
4on legs
1on right leg is a dumby - neutral
what to avoid before an ecg
creams / lotions
tight tops
full length tights
fancy name for low bpm
bradycardia
fancy name for high bpm
tachycardia
what does p wave represent in ecg
impulses passing from the SAN to the AVN through the walls of the atria
what does the qrs wave represent in ecg
shows the electrical impulses travelling down the Bundle of His and purkinje fibres
what does the t wave represent in ecg
T wave occurs as the ventricles recover
what is the p wave
Represents atrial depolarisation
what is the Q wave
The first downward wave of the QRS Complex (Q Wave is often absent)
what is the R wave
The initial positive deflection
what is the S wave
The negative deflection following the R wave
what is the T wave
Represents ventricular repolarisation
what happens in the qr interval
Depolarisation of the Atria in response to the SA Node triggering
what happens in the pr segment
Delay of the AV Node to allow filling of the Ventricles
what happens in the qrs complex
Depolarisation of the Ventricles, triggers main pumping contractions
what happens in the QT Interval
Is a measure of when the Ventricles contract to when they finish relaxing.
what happenns in the ST Segment
Beginning of Ventricle repolarisation, should be flat.
how to measure bpm on ecg
one big square = 1
one small square = 0.2
measure from brig of qrs wave to the next one
ee 3
divide by 300 = 300/3 = 100
what is bradycardia
under 60bpm
why does bradycardia happen
due to athletic training which increases stroke volume of the heart
pumps more blood per beat - bpm decreases
what is tachycardia
over 100 bpm
why does short term tachycardia happen
panic, fear, exercise
why does longer term tachycardia happen
problems with SA node - surgery or drugs may be required
what is an ectopic heartbeat?
an extra heartbeat that is not part of the hearts usual rhythm
ee heart contracts again before the first contraction has finished
followed by a short pause before normal rhythm continues
significance of a ectopic heartbeat
relitivly common and doesn’t pause any health risk
if frequent - indicates a more serious heart condition
what is atrial fibrillation
irregular waves of electrical excitation passing over the atria
atria contract radnomly and rapidly - electrical excitation not transmitted to ventricles (normally)
atryial fibrilliation is a type of ___
arythmia
what is the problem with atrial fibrillation
heart cannot pump blood normally - treated with medication / surgery
what is a sinus arthymia?
irrehular heartbeat - where the difference between the P waves is different (length ways) - can be naturally occuring or due to heart damage
when does ventricular fibrillation happen
during cardiac arrest
what is ventricular fibrillation?
ventricles contractions are irregular and uncoordinated
will rapidly loose consciousness and will die if treatment is not immediatly started
name of process that happens when 2 blood groups mix
agglutination
ECG lines accronym
PQRST
