Anatomy: Circulatory System Flashcards
functions of the circulatory system
- distribute gases + other molecules for nutrition, growth and repair
- chemical signalling (hormones)
- thermoregulation
- mediate inflammation and host defence responses
3 components of the cardiovascular system
- arterial
- heart
- venous
2 main circulations
- pulmonary
- systemic
route of pulmonary circulation
R side of heart -> lungs -> L side of heart
route of systemic circulation
L side of heart -> capillary beds of tissues and organs -> R side of heart
systole is
contraction
diastole is
relaxation
R side if heart contains _ blood
deoxygenated
L side of heart contains _ blood
oxygenated
3 layers of the heart
- epicardium (external)
- myocardium (middle)
- endocardium (internal)
the epicardium is
visceral serous pericardium
the myocardium is
cardiac muscle
the endocardium is
continuous w/ blood vessels endothelium connecting with the heart
what is the hearts normal conduction route
- spontaneous electrical impulse at SA node
- A contract
- travels to SA node at atrioventricular septum
- travels down L and R bundles in intraventricular septum
- spreads to myocardium through conducting fibres
- V contract
3 layers of blood vessels
- tunica intima (internal)
- tunica media (middle)
- tunica adventitia (external)
the tunica intima is
endothelium
the tunica media is
smooth muscle and elastic fibres
the tunica adventitia is
connective tissue
arteries have a _ lumen and are _ than veins
round
deeper
what is a neurovascular bundle
artery, nerve and vein
arteries supply a _
territory
what happens during vasodilation
artery smooth muscles relax and the lumen widens increasing blood flow
what happens during vasoconstriction
artery smooth muscle contracts and the lumen narrows decreasing blood flow `
anastamosis
arteries connect without intervening capillary network
what is the purpose of anastamoses and what is this called
- provide alternative routes for blood flow in case of occlusion
- collateral
what is the Circle of Willis
arterial anastamosis in the Brain
what is the purpose of the Circle of Willis
help prevent stroke
end artery
only arterial blood supply to a given area of the body (no collaterals)
what can an untreated occlusion cause
territory infarction
infarction
irreversible cell death due to hypoxia caused by loss of arterial blood supply
what vessel does all systemic blood enter first
aorta
what feature of the aorta maintains peripheral flow during diastole
elastic recoil from elastic walls
veins _ blood away from a _
- drain
- territory
venous blood is ‘pumped’ back to the heart via
- venous valves
- skeletal muscle pump
- accompanying vessels
venous valves ensure _ flow to heart
unidirectional
how does the skeletal muscle pump help venous flow
contraction of skeletal muscles in lower limbs push the. blood through the veins and up the limb
how do accompanying vessels help venous flow
as veins run in sheaths with an artery the pulsation of the artery pushes venous blood along
2 main venous systems
- hepatic portal venous system
- systemic venous system
describe the hepatic venous system
drains venous blood from absorptive parts of the GI tract and assoc. organs to liver for ‘cleaning’
describe the systemic venous system
drains venous blood from all other organs to SVC/IVC
capillaries are lined with
a single endothelial layer
capillaries allow _ exchange
gas, metabolite and waste product
lymphatic tissues collect
tissue fluid - fluid that leaks out of capillary beds
fluid in lymphatics is called _ and is carried through _
- lymph
- lymph nodes
describe lymph nodes
contain WBCS to filter out foreign particles and fight infection/cancer
lymph is returned to _ in the _ at the _
- central veins
- root of the neck
- venous angles
when can lymph nodes be palpated
when fighting infection or being taken over by spreading cancer
