Introduction to CVS Physiology Flashcards
State the functions of the CVS
To deliver O2 and nutrients to cells
To remove CO2 and metabolites from cells
Heat
Hormone transport.
How is output from the CVS variable?
Can vary from 5-30l/min
Vessels can redirect or store blood
How is pulmonary circulation described as being in series?
Because blood is pumped through one vessel (the pulmonary artery) and then another vessel (the pulmonary vein), therefore output must be equal.
State the other circulation that is in series
Between the hypothalamus and the anterior pituitary gland
How is circulation between the left heart and the organs of the body in parallel?
Because all the organs receive blood at the same time (but blood can be redirected as required by arterioles)
Explain portal and systemic supply to the liver
Blood is pumped to the liver from systemic circulation, however, the liver also receives deoxygenated blood from the gut’s capillary bed to its own capillary bed via the hepatic portal vein.
Describe the structure and function of elastic arteries e.g. aorta
Thick elastic wall dampens pressure variations.
Wide lumen and elastic wall release elastic tension.
Describe the structure and function of muscular arteries
Pump blood to regions of body.
Wide lumen and non-elastic muscular arteries act as low resistance conduit.
What type of artery has a low resistance conduit?
Muscular arteries
What vessels are called resistance vessels? Why?
Arterioles. Act as taps. Narrow lumen and contractile wall allows to control resistance and thus flow allowing regional redirection of blood.
What is the equation for flow?
Flow = Change in pressure (MAP-CVP)/Resistance (r^4).
What is the relationship between radius and resistance?
Increase radius, reduce resistance.
Describe the structure and function of capillaries
Gas exchange vessels.
Thin wall and narrow lumen
What vessels are called capacitance vessels? Why?
Venules and veins. Wide lumen and distensible walls allow for storage of up to 2/3 of blood. Structure allows regional distribution of blood between veins and other vessels plus heart,
What proportion of the body’s blood can be stored by capacitance vessels?
Venules and veins up to 2/3 of total blood
Describe the route of blood though the heart
Deoxygenated blood from systemic circulation enters the heart via the SVC and IVC. It enters the right atrium and flows through the tricuspid valve before entering the right ventricle. It then flows through the pulmonary semilunar valve into the pulmonary trunk and then either the left or right pulmonary artery.
Blood is oxygenated I n the capillaries of the lungs before it enters the left and right pulmonary veins and into the left atrium. It then passes through the bicuspid or mitral valve into the left ventricle. it travels through the aortic semilunar valve into the aorta and then travels to cells via the arterial system
Name the valve between the right atrium and ventricle
Tricuspid valve
What chambers does the bicuspid or mitral valve sit between?
Left atrium and ventricle
What kind of valve is between the left ventricle and the aorta?
Aortic semilunar valve
What structures does the pulmonary semilunar valve sit between?
Right ventricle and the pulmonary trunk
