CV pathophysiology
Terms
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- heart located in the
-
1) thoracic cavity
2) pericardial cavity
3) mediastinum
4) ventral body cavity - apex
-
inferiorly, close to the surface
to the left
resting on the diaphragm - base
- postero-superior
- pericardium
-
1) fibrous
2) serous=parietal&visceral - fibrous pericardium
-
external
conn.tissue
protection
anchors it to diaphragm & great vessel
prevents overfilling of the origin - visceral layer of serous pericardium
- epicardium
- pericardial cavity
-
in bet. parietal layer of serous pericardium & visceral layer of serous pericardium
filled with the pericardium fluid
decrease friction - myocardium
- blood supply is carried out by the coronary system
- Thebesian veins
- as mush as 40% of the venous return from the arterial muocardium directly to the R and L arterial cavities
- anterior venous system
- 3 veins that empty directly into the RA
- coronary sinus system
- a series of superficial veins covering mainly over the LV and draining the deeper myocardium
- coronary sinus
-
a large venous chamber
runs in the post part of the coronary groove
drains in teh RA near the tricuspid valve (thebesian valve) - 85% of coronary sinus outflow represents?
- venous flow from the LV
- cardiac cycle
- the cardiac events that occur from the beginning of one cycle to the beginning of the next
- each cardiac cycle is initiated by?
- spontaneous generation of an action potential in the SA node
- cardiac output
- the volume of blood ejected by each ventricle per unit of time
- CO
- CO=HR*SV
- CO at rest
- 5L/min
- CO to
-
brain 13%
cardiac muscle 4%
kidneys 20-25% - stroke volume
-
same for both ventricles
70-80ml - SV is affected by?
-
1) venous return
2) peripheral resistance
3) ANS - Starling's Law of the heart
- if all factors return constant, the SV is determined by the FORCE of the contraction
- the strength of contraction
- increase in proportion to the LENGHS of the vent. muscle fibers
- end-diastolic volume
- the quantity of blood in the ventricles just prior to their contraction
- end-diastolic volume determines
- pre-load
- pre-load
- the degree of tension of the muscle when it begins to contract
- after-load
- resistance against which the ventricles must pump
- baroreceptors
- sensors which respond to distension of arterial wall as a result of increase in pressure
- baroreceptors triggers
-
para-sympathetic stimulation
<HR, <cardiac contract., <CO, <BP - chemoreceptors
- respond to the concentration of O2 and CO2 in the blood (PO2 & PCO2)
- chemoreceptors located in
- carotid and aortic bodies
- Chordae tendineae
- bands of fibrous tissue that attach on one end to the edges of the tricuspid and mitral valves and on the other end to the papillary muscles that anchor the valves
- diastole
- coronary perfusion happens
- function of valve
-
is from PRESSURE gradient,
not depend on any muscular contraction - function of pulmonary circulation
- gas exchange and oxigenation of blood
- all organs have lymphatic vessels adn tissued except for?
- brain and liver
- SA node
-
pacemaker
60-100 IMPULSES/min (not beats) - isovolumetric contraction phase
-
bet. the start of vent. systole and the opening of the semilunar valves
there is contraction of the ventricles, but no empthying
a rapid rise in vent. pressure - isovolumetric relaxation
-
bet. the closing of the semilunar valves and the opening of the AV valves
a drastic decrease in vent. pressure without a change in vent. volume - ventricular filling
-
1) vent. filling
2) arerial contraction - ventricular systole
-
=atria in diastole
1) isovolumetric contraction phase
2) vent. ejection phase - early diastole
-
1) isovolumetric relaxation
2) ventricular filling