circulatory system Flashcards
what are the 2 names of the valves in the heart?
atrioventricular valve
= left one is mitral atrioventricular valve = 2 cusps
=right one is tricuspid atrioventricular valve = 3 cusps
semilunar valves
= aortic semilunar valve controls blood flow leaving left ventricle through aorta
=pulmonary semilunar valve controls blood flow leaving through right ventricle
what makes up the circulatory system?
cardiovascular system & lymphatic system
what is the functions of circulatory system?
- distribution of gases & other molecules for nutrition, growth & repair
- chemical signalling (hormones)
- mediate inflammation & host defence response
describe the pulmonary circulation
starting at right atrium -> right ventricle -> blood leaves through right & left pulmonary arteries to lungs (1 exception where arteries carry de-oxygenated blood) and then coming back from the lungs into left atrium through 4 pulmonary veins (1 excepetion of veins carrying oxygenated blood)
describe the systemic circulation
starting at left atrium -> left ventricle and then blood pumped out with oxygenated blood still through aorta (aorta divides to arterioles then capillaries for exchange where blood then deoxygenated then back to venules and then veins = superior & inferior vena cava that run into right atrium & back to pulmonary circulation
what is
a) systole
b) diastole
a) contraction
b) relaxation
what is orientation of heart? (describe anterior view)
mostly right ventricle stretching across front with right atrium at top and then left ventricle taking up most of left side with only a little bit of left atrium at top left
LA = posterior surface of heart
LV = mostly left border of heart & inferior surface
RA = right border
RV = most of anterior surface of heart
describe electrical conducting system of heart
- Electrical impulse starts spontaneously at sinoatrial node →Causing both atria to contract
- Travels to AV Node at atrioventricular septum
- Travels down right and left bundles in Bundles of His
- Spreads out to myocardium through conducting fibres →Causing both ventricles to contract
what does birfurcate & trifurcate mean?
when arteries split into 2 or 3 routes ( like tributaries in river)
what terms indicate that an artery will divide again?
common or trunk
what is vasodilation?
Relaxation of the smooth muscle and widening of the lumen to INCREASE blood flow to the organ/tissue supplied
what is vasoconstriction?
Contraction of smooth muscle to REDUCE blood flow to the organ/tissue supplied
what is sympathetic tone?
background or low level contraction of smooth muscle in arterioles due to tonic (continuous) conduction of action potentials to arterioles by sympathetic nerve
what is an anastamoses?
communicating connections between multiple branches of artery to provide numerous potential detours in case usual pathway obstructed (like knee flexion)
what does collateral circulation mean?
collateral circulation is when main channel occluded so smaller alternate channels can increase in size supplying blood supply to structures distal to blockage
what are names of arteries if they don’t do anastomoses?
true end arteries
what is problem with collateral circulation?
takes time to develop & often don’t compensate for sudden occlusion
what does infarction mean?
irreversible cell death due to hypoxia (oxygen not suitable supply to maintain homeostasis) caused by loss of arterial blood supply
what can lead to infarction?
untreated occlusion of an end artery - leads to infarction of it’s territory
when does aorta receive blood?
at high pressure during systole- elastic walls expand under this pressure & elastic recoil maintains peripheral flow during diastole
what are the 4 parts of the aorta?
- ascending aorta
- aortic arch
- descending aorta
- abdominal aorta
what are the 3 branches off the aortic arch?
- brachiocephalic trunk which then splits to right common carotid and right subclavian
- left common carotid
- left subclavian
what is the upper limb blood supply?
sublavian artery -> auxillary artery -> brachial artery -> anterior to elbow joint bifurcates to radial artery and ulna artery
what is the route of abdominal aorta blood supply?
branches to abdominal organs then common iliac arteries (R &L) -> bifurctaes to external iliac artery (lower limbs) and internal iliac artery (pelvis/perineum)
where are the peripheral pulses?
carotid (neck)
femoral artery (leg)
brachial artery (elbow)
radial artery (wrist)
popliteal artery (posterior to knee joint)
dorsalis pedis artery (dorsum of foot)
what are the 2 branches off the ascending aorta?
left & right coronary arteries
whats a neurovascular bundle?
nerve, artery vein
what are some key characteristics of veins?
- carry de-oxygenated blood
- low pressure & non pulsatile
- drain blood away from territory
- thin walled & collapse when empty
- veins have valves
what are veins returns back to heart assisted by?
venous valves - ensure unidirectional flow back to heart against gravity
muscular contraction - skeletal muscles in lower limb
venae comitantes - small veins run in pairs with an artery in a sheath so arterial pulsations push venous blood along
what are the 2 types of veins?
superficial & deep
what are superficial veins?
smaller and run in superficial fascia then drain into the deep veins
what are deep veins?
larger and run deep to deep fascia and in cavities
what are the 2 main venous systems?
hepatic/portal venous system = drains blood from GI tract & associated organs to portal vein
systemic venous system = drains venous blood from all other organs & tissues into superior & inferior vena cava
where is lymph returned?
returned to veins in root of neck
= thoracic duct drains lymph into left venous angle
= right lymphatic duct drains lymph into right venous angle
what happens in lymphatic circulation?
lymphatic capillaries collect tissue fluid (fluid that leaks out when blood flows through capillary) and once fluid there it’s called lymph
- lymphatics carry lymph through lymph nodes where white blood cells are, looking for infection
why is anatomical route of lymph nodes important?
you can predict where spread next e.g. cancer
why do you palpate lymph nodes?
because normal lymph nodes cannot be palpated (method of feeling in exam) but lymph nodes fighting infection or being taken over by spreading cancer can be palpated or seen on CT scan
what the is only lymphatic vessel large enough to be found in dissection?
thoracic duct
