Structure/function of circulatory system Flashcards
function of circularity system=
main transport sytem in body. responsible for 02 delivery, nutrients,hormones,medication taken to different parts of the body. also transports waste products (c02,lactic acid) for removal
what makes up the circulatory system?
heart, blood, blood vessels
what is the function and location of the heart=
heart is a muscular pump that pushes 02 etc around the body, its is myogenic, size of a mans clenched fist,
lies behind sternum just left of centre between left and right lung
what is heart rate?
- is stimulated to contract by complex integrated systems
- hearts pace maker is SA node (sinoatrial node) initiates cardiac muscle contraction and is located in right atrium wall
structure of the heart
- made up of thick muscular walls (myocardium), divided into separate left and right halves
- right half receives blood from body and pumps blood to lungs
- left half receives blood from lungs and pumps blood to body
what is the atrium/atria?
- chamber that blood flows into 1st when entering either side of the heart
- atria receives blood via veins from parts of the body and pumps blood down in ventricles
what are atria?
- smaller than ventricles
- do not contract particlully hard
- the atria can fail to contract properly , most of the blood in the atria still flows into ventricles passively
average adult HR?
72bpm
what do ventricles do ?
supply a force to push the blood to its various destinations
what do left/right side of heart do ?
left-pumps contents to furthest parts of the body
right-pumps to adjacent lungs
heart valves how many, what do AV and semilunar valves do? =
- no of different valves around heart !
- AV (atrioventricular) valves separate atria and ventricles and prevent flow of blood back into atria during ventricular contraction
- semilunar valves prevent back flow of blood back to right (pulmonary)and left ventricles (aortic valve) during ventricular relaxion
ventricular contraction=
systole
ventricular relaxion=
diastole
describe the movement of blood through the 4 chambers of the heart?
- 02 blood from lungs enters left atrium via pulmonary vein
- moves down to left ventricle
- pumped to body via aorta (gaseous exchange here, co2 blood from veins to heart)
- co2 blood enters right atrium via vena cava
- passed down to right ventricle and pumped to lungs via pulmonary artery
- gaseous exchange here, c02 removed, o2 taken in
*cycle repeats!!
what are the 4 components of blood?
1) red blood cells
2) white blood cells
3) platelets
4) plasma
describe red blood cells and their function
- called erythrocytes
- in soft red marrow, contain protein haemoglobin (iron rich pigment gives it the red colour)
- body contains 240-270million red blood cells in every drop of blood
- blood volume around 40% red blood cells
describe white blood cells and their function
- called leukocytes
- produced in red bone marrow, is transparent, no haemoglobin
- part of immune system
- cells destroy bacteria/other harmful living organisms and removed damaged r diseased tissue
describe platelets and their function
- called thrombocytes
- are cell fragments not whole cells; assist prevention of blood loss from a damaged blood vessel by forming a platelet plug
- release chemicals proving blood clotting
- initial stage for repair for damaged tissue
describe blood plasma
- straw coloured liquid portion of the blood
- mainly water (91.5%) and salutes (8.5%) like nutrients, gases, enzymes, hormones
describe structure of blood vessels and how many types?
different types of vessel categorised by shape and function
- all blood vessels linked to form continuous circulatory loop
- 3 TYPES OF BLOOD VESSEL
what are the 3 types of blood vessel
1) arteries
2) capillaries
3) veins
what are the 2 sub categories of blood vessel
1) arterioles
2) venues
what is pulmonary circulation
circulation between heart and lungs
- pulmonary heart chambers are left atrium and right ventricle
- pulmonary blood vessels are pulmonary artery/vein
what is systemic circulation
circulation between heart and body
- systemic heart chambers are left ventricle and right atrium
- systemic blood vessel are aorta, inferior vena cava (carries blood from lower body, superior vena cava from upper body)
deoxygenated blood is ….. and appears ….. when viewed through blood vessel walls
dark red, blue
what colour is oxygenated blood?
bright red
main function of blood vessels=
transport system for the blood. carry blood from heart to rest of the body and back again
blood is the medium that carries…………… to cell body structures and …….. and ………..
nutrients,02/ removes waste products/c02
define venous return
when the blood in veins pools in the extremities
what does VR do in relation to the heart?
it pumps harder/faster so volume of blood higher, when leg muscles stop working there is less assistance to veins to return to the heart
factors affecting VR
1) gravity (helps blood flow from above heart
2) skeletal muscle contraction (squeezing of muscles against veins increase blood flow and VR)
3) non-return valves in veins (prevents backflow of blood)
4) diaphragm (suction affect on veins below heart)
5) right atrium (sucks blood back, blood in chamber empies into ventricle below=vacuum blood from vena cava)
6) smooth muscle contraction (pumping action of smooth muscle constant (peristalsis)
why is VR vital ?
returns blood to the heart and prevents blood pooling
- long periods of inactivity=slow blood flow in legs=blood pooling
- blood clot/deep vein thrombosis may form=pooling raises due to blocked blood vessel
what is blood pressure?
force applied to the walls of arteries as it flows through them
what is the unit of measurement for blood pressure?
millimitres of mercury (mmHG)
optimal blood pressure=
120/80
what is systolic blood pressure?
pressure exerted on artery wall when cardiac muscle contracts/pumps blood
- usually higher no. on reading (noted 1st)
- caused by increase volume of blood flowing through arteries w/ each beat=higher pressure in arteries
what is diastolic blood pressure?
pressure exerted on artery wall when cardiac muscle relaxes
- heart goes through period of relaxion to allow chambers to fill w/blood before contraction
- always 2nd reading
calculation for blood pressure
cardiac output x total peripheral resistance
what is cardiac output
volume of blood ejected from heart in 1 min
what is total peripheral resistance
resistnace blood vessels offer to blood flow
what is blood circulation=
closed system where pressure varies constantly. in contraction it is peaked as heart pumps out blood them falls to a lower level just before each heartbeat
what are the short term effects of exercise on blood pressure
- linear increase systolic blood pressure w/ higher levels of exertion
- diastolic blood pressure may decrease due to vasodilation or remains the same
- weightlifting/isometric exercise increases systolic/diastolic pressure highly
long term effects of exercise on blood pressure
-aerobic exercises using large muscles in rhythmical activity vital to decrease blood pressure over time
what is the Vasdura Manoevure
expiratory effort against closed glottis leads to higher pressure in thoracic cavity and lower VR to heart
state 2 things Dustine and Moore 2003 said
1) endurance training can elicit average decrease of 10mmHg in systolic/diastolic pressure in mid/moderate hypertensives
2) with exception of circuit training, strength/resistance training does not lower resting blood pressure
short term effects of exercise on CV/respiratory system
- inceased HR
- higher SV
- increased Q (cardiac output)
- increase systolic blood pressure
- dilating capilleries
long term effects of exercise on CV/respiratory system
- stronger cardiac muscles
- lower resting HR
- more blood ejected in 1 contraction
- lower working HR
- more mitochondria
- sustained optimal blood pressure
definition of arteries
muscular tubes with thick walls that contract to squeeze blood along passageways away from heart
what is the aorta?
long artery that leaves left ventricle in heart
describe subdivision of artirioles
aorta-arteries-arterioles-capilleries
smooth muscle tissue surrounding artery/arteriole walls are ticker/more powerful than surrounding walls of veins, true or false
true
when blood ejected from heart, arterial walls need to …… to receive blood under high…..
stretch passively/pressure
are there any valves in arteries
no only at exits points of ventricles preventing backflow
do arteries carry 02 blood around body?
YES
definition of capilleries
have very thin walls (1cell thick) and speed to all parts of the body (even smallest area of tissue)
what occurs at capillary walls because they are so thin?
diffusion between nutrients/gases into tissue cells (food and 02 pass through walls from blood and into individual cells to be used. waste products pass back through cell walls to be excreted. blood flows through capillary bed to allow this to happen)
venules are what?
when capilleries have passed the tissue, they gradually link together to form larger blood vessels called venules then become larger=veins
what is the flow of capilleries ?
capilleries-venules-veins-vena cava
definition of veins
carry blood from tissues and back towards the heart, they have thinner walls than arteries with little muscular contractability
what do the smooth muscle walls in the veins do|?
they contract automatically in the peristaltic action to assist the return of blood
what do veins carry and name an exception
mainly carry CO2 blood, exception to this is Pulmonary veins/venules that carry o2 blood to heart
what pressure is in veins and effect it has ?
low pressure makes return up the body harder
what do all veins have?
1 way valves that work against gravity to prevent backflow of blood towards the heart
describe the circulatory blood flow
- blood vessels vasodilate/constrict due to smooth muscle found in walls
- enables body to direct flow of blood to different tissues (dependant on body state)
- after meal, blood vessels feeding digestive system vasodilated, blood vessel increases to increases digestion, blood vessel feeding muscles vasoconstricted= lower blood flow
- during exercise opposite occurs
eating to close to exercise =
cramp/vomiting
