Circulatory System Flashcards
components of circulatory system
pump (heart), blood, blood vessels
heart definition
pump that circulates blood through blood vessels
arteries– type of blood and whether in or out of heart
- usually oxygenated (except pulmonary artery)
- away from heart
veins– type of blood and whether in or out of heart
- usually deoxygenated (expect pulmonary vein)
- into heart
capillaries– placement and why
- connect arteries to veins
- close to cells so good supply of oxygen/ nutrients
- efficient removal of waste products
circulatory system– what it does
- transports nutrients
- transports waste
- regulates body temperature
double-circulatory system definition
for every one full circuit, blood passes through heart twice
advantage of double circulatory system
- higher pressure due to heart allows for blood to get to extremities (+ allows for bigger bodies)
why are arterioles used?
to diminish the pressure of blood going from arteries to capillaries (and prevent them from bursting)
how does blood get from arteries to veins? (2)
- artery-> arteriole->capillary-> venule-> vein
- artery->shunt vessel-> vein
valves in veins
- semi- lunar
what happens if blood flows backwards in veins
- they swell and blood cannot circulate properly
how do valves work?
- open when pressure inwards
- close when pressure put backwards on them
atrioventricular valves– where + names
- between atria and ventricles
- tricuspid (right side of heart)
- bicuspid (left side)
what circulatory system do fish have
single circulatory system
single circulatory system in fish path
organ-> vein-> heart-> artery-> gills-> arteries -> organs
right side of heart
- low pressure required (as little resistance to flow because lungs are a spongy tissue w/ air)
- deoxygenated blood from body to lungs
- gas exchange in capillaries in lungs
left side of heart
- oxygenated blood to rest of body
- higher pressure than right side
- left ventricle= most muscular chamber
- pressure of blood leaving heart is greater due to more resistance to flow
- gas exchange occurs in capillaries in in organs as blood flows through
how many pumps in heart
2– left side and right side
heart made out of
almost entirely cardiac muscle tissue
septum
- wall of tissue
- prevents oxygenated blood on one side from mixing with deoxygenated blood in other side
ventricles
- blood in when atria contract
- more muscular than atria as have to pump blood further
- left ventricle= more muscular as body= further away
cardiac cycle
- relaxation phase (where heart fills with blood)
- blood then goes to ventricles
- contraction phase (where heart pumps blood)
true or false– atria relax and contract at different times
false
relaxations phase
- blood into atria from veins
- semi-lunar valves close
contraction phase
- atria contract (= atrioventricular valves open)
- blood in ventricles
- ventricles contract (= atrioventricular valves close to prevent backflow
- blood in arteries ( then semi-lunar valves open)
ways of monitoring heart activity
- electrocardiogram (ECG)
- listening to sound of heart valves closing
- pulse points
what does control of heartbeat depend on
electrical activity
what is an ECG
a diagnostics tool that detects heart defects (as the can cause an irregular pattern)
how ECG used
electrodes taped to body in various places
heart’s electrical activity displayed on monitor
p wave on ECG
- atria contracting
QRS spike ECG
immediately precedes contraction of ventricles
T wave on ECG
ventricles relaxing
how is stethoscope used
- listen to heart sounds
- identify irregularities
how is heartbeat sound made
opening and closing of the valves
first sound of heartbeat how made
- during contraction phase
- pressure against atrioventricular valves shuts them
second sound of heartbeat
- during relaxation phase
- blood at high pressure in arteries causes semi-lunar valves to close
what happens during exercise
- muscles need more energy from respiration to contract
- heart beats faster
- arteries dilate
= increases blood flow to muscles
pulse definition
number of times left ventricle contracts per minute
how pulse felt
- ventricle contract
- sends wave through artery
- felt i.e. on wrist
resting HR in regards to fitness level
higher fitness level, lower resting HR
arteries characteristics
- thick muscular walls
- narrow lumen
- high pressure
veins characteristics
- wide lumen
- thin muscular walls
- low pressure
- valves
capillaries characteristics
- extremely narrow lumen
- 1-cell thick walls
- found near alveoli/ skin surface
how are capillaries made
the branching out of arteries (arterioles)
blood vessel walls made out of
muscle and elastic fibre
artery adaptations
- elastic fibres in walls recoil after stretching
- this helps push blood along to maintain high pressure
- result= pressure at end of artery is only slightly lower than when started
capillary adaptations
- large surface area for gas exchange
- blood flows slowly to give time for gas exchange
- short distance between blood and cell
vein adaptations
- blood squeezed along by muscle contraction/ organ contraction
arterioles
- sub-division of arteries
- blood carried to capillary network
- important for regulating blood pressure
- receive nerve impulses/ react to hormones to regulate their diameter
venules
- collect blood from capillary beds
- thin-walled
- unite to form veins
shunt vessels
- links artery directly to vein
- control body flow by dilation and constriction
- in endotherms, cold= constrict and hot= dilate
