cardiovascular Flashcards
purpose cardiovascular sys
- delivery O2, nutrients, hormones, enzs
- removal waste products + heat
what is present in thorax
- heart
- distal airways + lungs
- thoracic oesophagus
- thymus
- bvs
- lymph nodes + lymphatic vessels
label key parts + brief descr how articulate
13 ribs, each articulate w vertebra, 1st 9 connect sternum, rest to each other in costal arch except last = floating rib
where is heart located w/in thorax
bet lungs, ventral to hilus (root of lungs)
general lung anatomy
lungs, divided lobes, each fed by 1 secondary bronchus, divided lobules
RIGHT: 4 lobes - cranial, middle, caudal, accessory
* no middle in horses
LEFT: 2 lobes - cranial (further divided cranial + caudal portions), caudal
pleura
serous mem lining thorax, lining lungs - visceral adherant lung surface then parietal layer w serous fluid in pleural cavity between
* no friction, no sticking + gen neg press force lungs open
* parietal = diaphragmatic, costal + mediastinal (covers other organs in midline)
all connected
pericardium
invaginated serous mem sac containing heart w visceral + parietal layers sepped serous fluid (easy movement of heart) create potential space
layers heart wall
- endocardium = smooth inner lining
- myocardium = muscle
- epicardium = visceral pericardium
relative position heart + its parts
sits midline w apex deviated slightly to left
* base cranial + dorsal to apex
* right side cranial + to right of left
parts heart w pathway blood
lungs -> pulmonary vein -> left atrium -> mitral AV valve -> left ventricle -> aortic semilunar valve -> aorta -> tissues -> caudal/cranial vena cava -> right atrium -> tricuspid AV valve -> right ventricle -> pulmonic SL valve -> pulmonary artery -> lungs
all bvs enter/leave at base
coronary circulation
supplies heart muscle w blood - coronary arteries to, great cardiac vein from
5% of circulation
heart septums
interatrial = thin muscular wall
interventricular = v muscular, acc part left ventricle
structure AV valves
have fibrous cusps - parts that ‘open + close’
* mitral has 2
* tricuspid has 3 - that can vary in dogs
supported by fibrous skeleton to maintain structure
atrial appendage
= auricle - extra section to each atrium that also fills + empties
order systole + diastole
- atria fill passively, press increases so AV valves open
- ventricles fill passively, then atria contract to complete emptying + AV valves close = atrial systole
- ventricles contract but all valves closed = isovolumetric ventricular contraction
- press increases enough for SL valves open, ventricles still contracting = ventricular systole
- SL valves close, ventricles relax = isovolumetric ventricular relaxation
- AV valves open again, ventricles begin fill = ventricular diastole
systole = emptying, diastole = filling
isovolumetric contraction/relaxation why?
press in chamber has be increased before valves open - if all valves closed then vol constant
pressure volume loop
graph diagram thing
what causes heart sounds
generally
movement blood = blood turbulence as it bounces off surfaces
normal heart sounds causes
S1 = blood rebounding in ventricles after AV valves close
* also as it accelerates in aorta after aortic valve opens
S2 = blood decelerating in great blood vessels after SL valves close
marking start + end ventricular systole
abnormal heart sounds
S3 = blood flowing into ventricle under press heard due reduced compliance ventricle wall in early diastole
* due heart failure in smallies
S4 = ‘stiff’ (impaired relaxation) ventricle wall causes increased force atrial contraction
murmurs caused blood turbulance due anything disturbing normal bloodflow
S3 + S4 normal in horses due larger heart, ‘gallop rhythm’ in smallies
auscultation heart dogs
LEFTSIDE RIB SPACES
* pulmonic valve = 3
* aortic valve = 4
* mitral AV valve = 5
RIGHT SIDE RIB SPACES
* tricuspid valve = 4/5
how is heart cycle driven elec activity
v simplified pathway
stims muscles contract rhythmically
1. initial impulse gened sinoatrial node
2. passed AV node + conducted slowly give atria time contract fully + empty
3. passed bundle of His
4. passed Purkinje fibres, then stim all ventricle muscle contract at once
function valve
ensure blood flow correct direction by opening + closing according press changes
structure valves
made cusps that open/close due press changes - 2 @ mitral, 3 @ tricuspid (not dogs - 2 main, other commissural)