CV Flashcards
functions of CV
exchange; communication; defense (inflammatory response, antibody-antigen interaction, homeostasis);
what acts as a pressure resevoir?
the elastic systemic arteries
what acts as a volume resevoir?
the inelastic systemic veins
where is the site of variable resistance?
in the arterioles
basic components of the CV system
Muscular pump (heart) Distribution networks (blood vessels) Transport medium (blood)
general info about the muscular pump
located in the thoracic cavity; 4 chambers; 2 atria & 2 ventricles
The heart is on the ventral side of the thoracic cavity, tilted to the right and in between the lungs
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Cardiac notch
(indentation of the left lung next to the heart)
what is cardiac tamponade?
Buildup of pericardial fluid within the pericardial sac causes a decrease in cardiac output
what is the purpose of the fibrous rings?
Fibrous rings (skeleton) function as an electrical insulator, preventing the propagation of electrical impulse from atria to ventricles through contractile myocytes
subsystems of the heart
i) Pacemaker & conducting systems
ii) Heart muscle (myocardium)
iii) Heart valves
iv) Coronary circulation
v) Autonomic innervation
what is ectopic focus?
any part of the heart other than the SA node that generates a heart beat
which conducting system has the slowest conducting velocity?
AV node– need to allow for ventricular filling; limits freq of ventricular activation
which conducting system has the highest conducting velocity?
purkinje fibres; fast and coordinated ventricular contraction
what is syncytium?
With intercalated disks & gap junctions, cardiac muscles can contract as an unit with a single impulse
how are impulses conducted from the SA node to the left atrium?
through the interatrial pathway (Bachmann’s bundle)
what is prolapse
Condition that the chordae tendineae fail and valve is pushed back into the atrium
during ventricular contraction, giving rise to ventricular regurgitation
coronary artery originate
The right coronary artery originates from the right coronary orifice (sinus of Valsalva). The left coronary artery originates from the left coronary orifice and after a short course, bifurcates into the anterior interventricular artery, also known as left anterior descending artery (LAD), and circumflex artery
how does the parasymp system modulate the heart?
innervates mainly atria; negatively chronotropic–decreases HR
how does the symp system modulate the heart?
positively chronotropic and pos inotropic (force)
what are the divisions of blood vessels?
1) Systemic circulation containing aorta, arteries, and
arterioles
2) Capillaries
3) Venous circulation including venules, veins, and vena cava
what are the major portal system?
1) Blood enters into the digestive tract and later re-enters the liver
2) In kidney’s filtration systems
3) Hypothalamic-hypophyseal (pituitary) portal system
Capillary beds connected in series with each other
why is there parallel arrangement of circulatory systems?
Adequate distribution of oxygenated blood into all the organs
Each organ will receive the same oxygenated arterial blood with approximately the same perfusion pressure
Arteries are known as resistance vessels Veins are known as capacitance vessels
One of the most important functions of the blood vessels is for volume & pressure regulation
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