lecture 3 - cardiovascular physiology Flashcards
(45 cards)
where does gas exchange take place?
between the blood and tissues
what are the functions of the cv system?
circulate o2 and co2, provides cells with nutrients, removes waste products of metabolism, clotting, regulate body temp, transport hormones, protect body against disease and infection
what happens in the heart?
blood flows from the right atrium to the right ventricle - deoxuygenated blood - then pumped to the lungs where it receives o2 - flows into the left atrium to the left ventricle where its then pumped around the body
what blood does the right side of the heart receive?
deoxygenated
what blood does the left side of the heart receive?
oxygenated
what does the bicuspid valve do?
causes a one way blood flow
what does the aortic valve do?
prevents blood flowing back into the heart between contractions
what does the superior vena cava do?
transports deoxygenated blood from upper body to right atrium
what does the inferior vena cava do?
transports deoxygenated blood from tissues below the heart to the right atrium
what are arterioles?
“resistance vessels” containing circular layers of smooth muscle, which can either constrict or relax to regulate blood flow to the periphery which allows redistribution of blood
what is blood pressure and what does it do?
cardiac output x total peripheral resistance - propells more blood out and increases output on the arterial walls
what is total peripheral resistance?
vessel diameter, vessel length, blood viscosity
what does the venus system do?
deoxygenated blood returns to the heart via the superior and inferior vena cava
why do arteries have thicker walls than veins?
more difficult for blood to be propelled through veins
what is myosin?
has myosin heads which bind to actin and pull it to the middle of the sarcomere which causes it to shorten and causes force to be generated
what is cardiac cellular structure and function?
During contraction of a cardiac muscle cell (cardiomyocyte), myosin heads pull actin towards the centre of the sarcomere, generating the force for contraction of the heart
what is depolarisation?
excitable cells - heart muscle cells can be activated, measure charge in the interior of the cell, due to diffs in the intracellular and extracellular concentrations of ions
pos ions flow into the cell so that it is less polarised
what is repolarisation?
pos ions flow out of the cell
what do action potentials mean?
causes an alteration in this permeability, sodium and ca cant enter the cell, permeability of this outcome changes, causes an influx of pos charged ions
what does the sinonatrial node do?
Specialised muscle tissue located in the top right of the right atrium which spontaneously depolarises and repolarises, which spreads throughout the right atrium to the atrioventricular node
what does the AV node do?
Specialised muscle tissue located near the interatrial septum which receives signals from the SA node and, following a brief delay, transmits them to the ventricles
what is step 1?
The SA node transmits a wave a depolarisation which begins to spread across the right and left atria
what is step 2?
Depolarisation is complete, and the atria contract, pumping blood into the ventricles.
When the depolarisation reaches the AV node, the impulse is delayed
what is step 3?
Ventricular depolarisation begins, traveling through the Bundle of His and onto the right and left ventricles (in orange in the image)
Simultaneously, there is repolarisation (relaxation) of the atria (in red in the image)
