1 - Overview Flashcards
Major functions of cardiovascular system
-transport essential nutrients
-remove bi-products
-regulate temp
-humoral communication
-nutrient supply to tissues - will change based on
physiological state
Why is the heart considered 2 pumps?
R = pulmonary circulation (16%) L = systemic circulation (84%)
What parts of the heart cause unidirectional flow
Valves tricuspid pulmonary mitral/bicuspid aortic
What part of circulation distributes blood to the tissues
arteries and arterioles
What part of circulation contains the majority of total blood volume?
venous - systemic
Where does the greatest resistance to blood flow occur?
arterioles
What is the function of capillaries
exchange between blood and interstitial fluid
electrolytes, nutrients, hormones
As cross-sectional area of vascular bed increases, the velocity of blood flow does what?
decreases
There is an inverse relationship
Is blood flow pulsatile or non-pulsatile at the capillaries?
non-pulsatile- allows for exchange
What contributes to optimal conditions for capillary function?
slow flow (low velocity), low pressure, thin walls
What is the control of blood flow related to in the majority of the tissue beds in the body?
tissue needs
What is cardiac output (flow) controlled by?
sum of local tissue flows
Which pressure is controlled independently?
Arterial
What drives organ blood flow?
PRESSURE differences, not drive by cardiac output!
Describe the boundaries of the mediastinum
diaphragm to thoracic inlet
thoracic inlet to T4 - superior
T4-T12 inferior aspect - posterior/mid/anterior
In what part of the mediastinum does the heart live?
mid
Layers of Pericardium
Fibrous
Serous - contains parietal (outer)
contains visceral (inner wall, contact with heart)
What nerves travel across pericardium to the diaphragm?
Phrenic Nerve
*originates at C3-5
Sympathetic Innervation of the Heart
“speed up”
- T1-4 = cardiac accelerators
- stellate ganglia (cervico) and middle cervical ganglia
- innervate SA & AV nodes
- HR & contractility increase
- CO increased
Parasympathetic Innervation of Heart
“slow down”
- Originates at medulla oblongata –> Vagus nerve
- much innervation to SA & AV (decrease in rate)
- little innervation to ventricles (decrease contractility)
Conduction System: Parts
SA - sinoatrial node AV - atrioventricular, bundle of His Bundle Branches LBB - left anterior division, left posterior division RBB
Right Atrium - structures
cirsta terminalis - divides R atrium R atrial appendage - R auricle fossa ovalis (foramen ovale) eustachian valve tricuspid valve
Coronary Sinus
- collection of veins joined together to make large vessel that collects blood from the heart
- drains to the R atrium
Tricuspid Valve
3 leaflets
divides R atrium from R ventricle
R ventricle shape - cross sectional
crescent shaped
RV thickness compared to LV thickness
L is thicker
Cross sectional shape of L venricle
circular
How many pulmonary veins are normally present
4
2- right lung
2- L lung
Where do the pulmonary veins drain to?
pulmonary veins carry oxygenated blood from lungs to L atrium.
Where are clots likely to form in L atrium
L atrial appendage
*particular risk with a fib
Papillary Muscles - function & place
- attach aterioventricular valves via chordae tendonae
- contract to prevent inversion/prolapse during systole
Which valves have papillary muscles?
tricuspid & bicuspid
How many leaflets does a normal aortic valve have?
3
Where are the origins of coronary arteries in r/t aortic valve?
R & L main coronary arteries originate from sinuses of valsalva (which is just above aortic valve)
Mitral Valve - leaflets?
2
anterior - wide & short
posterior - narrow & long
Pulmonic Valve - leaflets?
3
anterior, L, R
Coronary Artery Branches
R main - dominance in 85%, supplies posterior of heart
LAD
L circumflex
Ramus Intermedius
3rd branch of L main coronary artery
present in 37% of ppl
Coronary Arteries - what determines dominance?
the artery that supplies the posterior third of the atrioventricular septum
LAD supplies to which myocardial segments?
front and bottom of L ventricle
front of septum
L circumflex supplies to which myocardial segments?
L atrium
side and back of L ventricle
R main coronary artery supplies which myocardial segments?
inferior portion of posterior L ventricle
basal posterior of L ventricle
AV node
