cadiovascular system 2 Flashcards
which is bigger atria’s or ventricles
atria’s smaller with thinner muscular walls as only push blood down to ventricles
requires little force
ventricles larger with thicker muscular walls in order to push blood out of heart
which side is larger
left side is larger as has to push blood around whole body
right side only have to pump deoxygenated blood back to lungs which is in close proximity with heart
chemoreeptord
ccc
detects chemical changes
during exercise, detects changes in c02
c02 imporant in controlling HR
increase in concentration of c02 stimulates sympatheic nervous syetm, heart will beat faster
baroreceptors
establish set point for blood pressure
if below or above blood pressure
sends signal to medulla in brain
increase in arterial pressure, causes increase in stretch, decreases HR
during exercise, set point increases
proprioceptors
located in muscles, joints and tendons
provides info about movement
start of exercise, detect movement
hormonal control mechanism
hormones can also have effect on HR
release of adrenaline known as hormonal control
adrenaline-stress hormone released by sympathetic
cardiac conduction system
send electrial impules to cardiac muscle
sa node
av node
bundle of HIS
punkji fibres
sa node
pacemaker-sets pace of the signal
myogenic-beat startes in heart muscle itself with signal in sa node
signal spreads across heart (wave of excitation)
spreads through walls of atria causimg them to contract and forceblood down to ventricles
av node
delays the transmisson of the cardiac impulse for around 0.1 seconds to allow the atria to fully control and venticular systole to start
bundle of HIS
located in the septum
bracnhes out tinto two bundle branchez
moves into smaller branches
called as punkji fibres
punkji fibres
spread throughout ventricles causing them to contract
hormonal control mechanism
has effect on HR
release of adrenaline during exercise-hormonal control
adrenaline is a stress hormone
released by sympatheic nerves
stimulates SA node
increases both speed and force of contraction, increases cardiac ouput ‘
stroke volume
volume of blood pumped out of the ventricles per contraction
can be influenced by venous return and the stretch of the cardiac fibres
venous return-volume of blood returning to heart via the veins. if venous return increases, so does stroke volume(more going out of heart, the more coming in)
starlings law
increase in venous return=greater diastollic filling phase=greater stretch of cardiac muscle=larger force of contraction=increased ejection fraction
cariac output
volume of blood pumped out of ventricles per minute
heart rate
number of times heart beats per minute
HR in response to exercise
increases directly proportinately with the increase in intensity of exercise
does however reach a max HR
calculated by 220-age
sub maximal exercise graphs explained
stready state as athlet can meet oxygen demadn to oxygen supply
hypertrophy
when the cardiac muscle gets bigger and stronger
caridac output in response to exercise
increases due to increase in SV and HR
when hits max intensity, it plateaus
how do you calculate Cardiac Output
HR times SV
stroke volume in response to exercise
increases as intenstity increases
when max effort reached, also plateaus
CHD (conary heart disease)
occurs when your conary atreiers that supply oxygenated blood to heart mucsclr, become blocked or start to narrow due to gradul build up of fatty deposits
process called atheroscelorisis
fatty deposits are called atheroma
what are the fatty deposits called that build up in conorary arteries causing CHD
atheroma
whta can cause atheroscelerosis
lack of exercise
high levels of chloestrol
smoking
what is angina
pain and discomfot found when conory arteries are blocked so cant deliver oxygenated blood to heart msucle
what causes a blood clot
piece of atheroma is broken off in conary artery, cutting of oxygenated blood supply to cardiac msucle
resulting in Heart attack
what are the two types of cholestrol
LDL-bad cholesterol as increase risk of HD
HDL-good cholesterol as lower risk of HD
exercise lowers LDL levels and increases HDL levles
stroke
occurs when blood supply to brain is cut off
cardiovascular drift
cariodvascular increases=heart rate increases=strove volume decreases=beacuse fluid lost as sweat=resulting in reduced plasma vokune=reduced venous return=cardiac output increased due to more energy needed to cool body/sweat
blood vessels in order
heart=arteries=arterioles=capilerries=venules=veins=heart
characteristics of veins
thin elastic tissue layers
valves and wide luman
charcteristics of arteries
small lumen smooth inner layer
capilleries
only wide enough to allow one red blood cell to pass through at a given time
systolic pressure
pressure in arteries when ventrices are contracti g
diastolic pressure
pressure in arteriers when ventricles are relaxing
evenous return mechnisms
skeletal msucle pump
repiratory pump
pocket valves
skeletal muscle pump
mucles contract and relax, change shape
this cahnge of shape means they press on nearby veins
causing pumping efect
and blood squeezed back to heart
repiratory pump
whne we breath in and out, pressure levels change
chnages in pressure, compress nearby veins
causing them to bring blood bakc to heart
pocket valves
prevent blood backflow
assue blood is flowing in one direction only
impact of blood pressure on venous return
systolic pressur -pressure in the arteries when the ventricles contract
dystoic pressure-pressure in arteries when ventricles relax
as venous return increases, so does blood pressire
when decreses, so does blood pressure
transportaion of oxygen
capilleries-when oxygen diffueses into cappileries 3& dissolves in plasma 97% of hb combines with oxygen causing oxyhamoglobin #when fully saturated, hameoglobin will carry 4 oxygen molecules
tissues-release of oxygen fromoxyhamgolib takes place-called oxyhamogolib dissocistion
muscles-oxygen stored as myoglobin
higher affinity for oxygen
will store the oxygen for mitochondira until used by the muscles
redistribution of blood
durig exercise, redistibution of blood is higher as needs to go to muscles that need oxygen
redistribution to areas of body that need it most-vasuclar shunt mechnism
perfomers should not eat any later then hour before comp, as blood wil be redistributed to stomach rather then working muscles
blood flow to brain must remain constant
tidal volume
volume of air breathed in and out per breath
increases during exercise
minute ventilation
volume of air breathed in and out per minute
big increase during exercise
inspiratory reserve volume
volume of air that can be forcfully inspired after a normal breath
decreases during exercise
expiratory reserve volume
volume of air forecefully expired after a normal breath
slightly decreases during exercise
residual volume
volume of air left in lungs after max expiration
stays the same during exercise
