structure of heart Flashcards
what splits up heart into two
muscular wall septum
charactertistics of atriums
thinner muscular walls than ventircles as only ahve to push blood down to ventricles
charactersutics of ventricles
thicker muscular walls as need greater force of contraction to push blood out of heart
what does the right side of heart do
pumps deoxygenated blood to lungs
what does left side of the heart do
pumps blood all around body so much larger
blood vessels of heart
vena cava-brings deoxygenated blood back to right atrium
pulmonery artery-takes deoxygenated blood from right ventricle to lungs
study tip: VAPA
pulmonery vein-brings oxygenated blood to the left atrium
aarota-takes oxygenated blood from left ventricle to rest of body
study tip: PVA glue
what do valves do
assure blood flows in only 1 direction
prevent blood backflow
names of two valves in heart and their location
tricuspid valve-between rigth atrium and ventircle
bicuspid valve-between left atrium and left ventricle
cardiac conduction system 4 parts
sa node
av node
bundle of his
punjkji fibres
what does the cardiac conduction system do
group of cells located in wall of heart which send elctrical impulses to the cardiac muscle causing it to contract
sa node
pacemaker
heart muscle described as myogenic as starts the beat itself (self regulating)
with electical signal in SA node (sinoatrial node)
signal speads through heart in wave of excitation
impulse spreads through walls of atria, causing them to contract and forcing blood to ventricles
AV node
delays the transmission of cardiac umpluse for approximaelty 0.1 seconds to allow atria to fully contract before ventricular systole begins
bundle of his
then pass through fibres which form the bundle of his
located in septum, seperate the ventricles into two
punkji fibres
bundle of his then branches out into two bundle branches and then moves into smaller bundles called punkji fibres
spread throughout ventricles causing them to contract
av node
delays the transmission of cardiac impulse by 0.1 secs to allow atria to fully contract before ventricular systole begins
bundle of his
located in septum
branches out into two bundles and then moves into smaller bundles (punkji fibres)
punkji fibres
spread throughout ventricles causing them to fully contract
sympathic nervous system
stimulates heart to beat faster
parasympathetic nervous system
returns heart rate back to resting level
what 2 systems are nervous sytem made up of
central nervous sytem-bain and spinal cord
peripheral nervous sytem-cells which transmit info to and from CNS
medualla oblagata
contains CCc (CARDIAC CONTROL CENTRE) which is stimulated by chemoreceptors, baroreceptors and proporioreceptors
chemorecetors
sense chemical changes
excercise, detect increase in CO2
co2 import in controlling HR
increase in concetration of c02, stimulates sympathetic nervous system, increases heart to beat faster (HR)
baroreceptors
sense changes in blood pressure
establish a set point for blood pressure
any increase or decrease from set point, signal to meduall in brain
increase in artieral pressure, increase in stretch of baroreceptors, decrease in heart rate
decrease in arterial pressure, decrease in stretch of barorecpetors, increase in HR
proprioreceptors
decect changes in muscle movemebt
start of execise, decet increasse in muscle movement
send signal to medulla
sends signal through sympathiec nervous sytem
to SAN to increase HR
signals parasyapthic nervous sytem, HR decreases
homronal control mechanism
release of adrenaline
stimulaes sa node
increase in both speed and force of contraction
increases cardiac ouput
more blood pumped out to working muscles so can recieve more oxygen
stroke volume
volume of blood pumped out of heart ventricles per contraction
venous return
volume of blood returning back to heart via the veins
what does SV depend on
venous return-if venous return increases so does sv, more blood entering the heart, more blood leaving geart
elasticity of the cardiac fibres-about starlings law
greater the stretch of cariac muscle, greater the force of contacrtion, greater the force of contactiom increase ejection fraction
disatole phase
heart relaxes to fill up with blood
what is ejection fraction
the percentage of blood pumped out of left ventricles per beat
starlings law
increased venous return, greater diastolic filling phase, cardiac muscle stretched, more force of contraction, increased ejection fraction
cardiac output
volume of blood leaving heart venticles per minute
how do you work out cardiac ouput
SV times HR
how do you figre out max heart rate
220-age
cardiac hypertrophy
heart gets bigger and stronger
bradycardia
decrease in resting heart rate bwloe 60 bpm
what is the relationshi between cardiac output and increase in exercise
increase in exercice, causes increase in hr, therefore sv, therefore cardiac ouput
what is the response of SV to exercise
increases as exercise intensity increases
only up to 40-60% max effort
then it plateus
this is sue to shorter diastolicc philling phase, so ventricles do not have as much time to fill up with blood so can not pump as much out
how does CHD happen
conaray heart disease
caused by conaray crteries, supply heart muscle with oxygenated blood, become blocked or start to narrow due to build up of fatty depositts-process called atherosclerosis
fatty deposits are called atheroma
what causes artherscelorisis
smoking
lack of exercise
high levels of cholestrol
what is the pain and discomfot called
agina
happens due to conoary anteries nt being able t deliver enough oxygen to heart causing pain and discomfort
what happens if fatty deposit breaks off
can cause a blood clot
results in blockage forming and cut off oxygenated blood getting to heart
can cause Heat attack
what are the two types of cholestrol
LDL-classed as bad cholestral link t heart disease
HDL-good cholestral as reduce risk of heart disease
what is cardiovascular drift
gradual increase in HR even tho intensity stays the same
occurs during prolgonged exercise (over 10 minutes)
warm conditions
how does carsdiovascaulr druft take place
due to sweat
portion of lost fluid volume comes from plasma volume
decrease in plasma volume reduces SV and venous return
heart trate increasses to compensate and maintain cardiac output
to attempt to create energy to cool body down
to minimmise cardiovascaulr dift, important to maintain high fluid consumption before and during exercise
venous return
return of blood to right side of heart via the vena cava
what are the 3 venous return mechnisms
skeletal muscle pump
repiratory pump
pocket valves
skeletal muscle pump
when muscles contract and relax, change shape
change in shape means muscles press on neraby veins causing pumping efefct and squeezing blood back to heart
repsiratory pump
when muscles contract and relax, pressure chnages
changes in pressure press nearby veins, causing blood to push back to heart
pocket valves
prevent blood backflow
assure blood flows in one direction
therefore, more blood back to heart
impact of blood pressure on venous return
when systolic pressure increases so does venous return
when systolic pressure decreases so does venous return
transportation of oxygen in capilleries
dissolves in capilleris
3 perectn dissolve into plasma
97% combine with haemoglobin to form oxyhaemoglobin
transportaion of oxygen in tissues
oxygen released form oxyhaemoglin due to lower pressure there (oxyhemoglobin dissociation)
transwporation of oxygen in muscles
oxygen stored in myglobin
higher affinity for oxygen and stores oxygen for mitochrondiea
where aerobic repsiration takes place
what is the bohr shift
s shape curve shifts to the right
when there is an increase in blood carbon dixoxide, decrease in PH results in a reduction in the affinity of haemoglobin for oxygen
what is vascualr shunt mechnism
redistirbtuion of blood flow to areas where it is most needed
known also as shunting
why should perfomers not eat less than an hour before comp
as blood will be distributed towards stomach rather than working muscles
vasoconstriction
narrowing of blood vessels to reduce blood flow into the capilleries
vasodilation
widening of blood vessels to increase blood flow into the capilleries
what is the VO2 difference
difference in the oxygen content of the arterial blood arriving at the muscles and the venous return leaving the muscles
