Heart anatomy Flashcards
2 circulatory systems
systemic - around body
pulmonary - to lungs and back
2 forms of the heart
systolic - contracted
diastolic - relaxed
3 layers of the heart
Epicardium, myocardium + endocardium
features of epicardium
serous (moisture exuding) layer that protects heart
lubricates pericardial cavity between 2 pericardial layers with pericardial fluid
myocardium
muscular layer of heart, thickness varies around heart - thicker around left ventricle
endocardium
epithelial layer surrounding the heart. consistent with blood vessels
function of circulatory system
- distribution of gases + nutrients
- Chemical signalling
- Thermoregulation
- Inflammation + immure response
3 component systems
- heart
- venous
- arterial
2 circulatory systems
- pulmonary
- systemic
4 valves in order from vena cava to aorta
tricuspid, pulmonary, mitral, aortic
3 layers to blood vessels + 2 elastic fibre layers
- tunica intima
- internal elastic fibre
- tunica media
- external elastic fibre
- tunica adventitia
Features of tunica intima
endothelium (type of epithelium) consistent with endocardium of the heart
- basal lamina
- thin layer of connective tissue
Features of tunica media
elastic fibres and smooth muscle layer
Features of tunica adventitia
connective tissue
Features of arteries
Thicker tunica media - cope with pressure
- located deep in body
- elastic walls expand under pressure, constrict when not to keep blood flow continuous
- elastic fibres replace smooth muscle layers
- vasa vasorum
sympathetic tone
standard lumen size adopted due to tonic (continuous) sympathetic innervation
increased/decreased sympathetic tone
increased- vasoconstriction
decreased- vasodilation
define Anastomosis
when 2 arteries come together without going through capillary network
features of anastomosis
- alternative route for blood flow (collateral)
- severed anastomosis bleed from both directions
Features of End artery
-only artery to supply a particular region
- occlusion (blockage) leads to infarction
(irreversible death by hypoxia)
4 parts of the aorta
- ascending aorta
- arch of aorta
- thoracic aorta
- abdominal aorta
define bifurcation + trifurcation
artery splits into 2 - 3
branches of ascending aorta
right/left coronary arteries
branches of arch of aorta
- brachiocephalic trunk
- left common carotid artery
- left subclavian artery
thoracic aorta to abdominal aorta
become abdominal when it passes the diaphgram
contents of neurovascular bundles
arteries, veins + neurones
Features of veins
- thin walls, collapse when empty
- valves to prevent backflow of blood
3 mechanisms of venous circulation back to heart
- venous valves
- skeletal muscle pumps
- accompanying veins
venous valves
- valves prevent backflow of blood, ensures unidirectional flow
skeletal muscular pumps
- muscles contract squeezing blood towards heart
accompanying veins
- veins surround arteries and use the pulsation of arteries to push blood through
2 types of veins
- superficial and deep
2 venous systems
- hepatic portal
- systemic
Features of lymphatic circulation
- drains tissue fluid (becomes lymph)
- drains to nodes
- wbc conduct surveillance
- returned to systemic system at root of the neck
generation of a heart beat
sa node
av node
bundle of his
purkinji fibres
hearts ability to beat uninnervated
autorhythmicity
elastic recoil
- elastic fibres recoiling during diastole to keep B.P relatively constant
vasa vasorum
- blood supply to tunica media and adventitia as they don’t receive nutrients from lumen of artery
features of arterioles
- reduce in size
- tunica media has only 1/2 layers of smooth muscle left
features of capillaries
- endothelial cells + basal lamina
3 types of capillary
- continuous
- fenestrated
- discontinuous
continuous capillaries
- endothelial layer continuous around entire lumen of capillary
- muscle, nerve, lung + skin
fenestrated capillaries
- small pores in endothelium to allow exchange of materials
- glands, kidney + mucosa gut
discontinuous capillaries / sinusoidal
- large gaps in endothelium
- liver, spleen + bone marrow
arteriole to venule ( intermediate vessels)
arteriole - metarteriole - capillary - post capillary venule/ thoroughfare channels - venule
features of large veins
- thick tunica adventitia with longitudinal smooth muscle
