31. Cardiovascular System Flashcards
why do mammals need a circulatroy system?
exchange of nutrients across membranes via a moving fluid so diffusion can occur at specific sites
whats the difference between an open and closed circulatory system?
in an open circultory system there is no distinction between blood and intestinal fluid, in closed circulatroy system blood is contained in blood vessels
what are three advantages of a closed circulatroy system
- better at transporting circulatroy fluids to meet high metabolic demand
- good for large animals
- ability for highly developed mammals
what seperates the heart from oxygenated and deoxygenated blood?
the septum!
what are the two types of circulation and what do they do in the body?
pulmonary circulation - moves blood between the heart and lungs via the pulmonary vein and arteries
systematic circulation- moves blood to the entire body via the aorta and returns it via the vena cava
what are the two functions of the right side of the heart
- recieves deoxygenated blood from the systemetic circuit
- pumps deoxygenated blood to the lungs of oxygenation (pulmonary circuit)
what are the two functions of the left side of the heart?
recieves oxygenated blood from the lungs (via the pulmonary circuit)
pumps oxygenated blood into the body (systematic ciruclation)
what is stroke volume (SV)
the amount of blood pumped from the left ventricle per heart beat
whats the definition of a heart rate?
the number of beats (cardiac cycles) per minute
what is cardiac output? (Q)
the stroke volume multiplied heart rate
Q = SV x HR
what is the normal cardiac output?
5 liters per minutes (for a 70kg male)
what do arteries branch into and then what do they branch into?
arteries branch into arterioles
arteioles branch into capilaries
what is the structure and function of arteioles?
arteioles are made of two layers of smooth muscle which can alter their diamete
this menas they reguate blood flow - eg thermoreguate and exerciese
how does the venous system continue push blood back to the vena cava? 2 points
veins have valves! this assists blood flow so its unidirectional (no back flow)
skeletal muscle pump - deep viens which veins are assited by muscle contractions
what is precapillary sphincters?
the opening or closing of capillaries to control blood distribution
what occurs in the cardiac cycle?
- right ventricle fills with blood passivley and active from atrium contractions
- pressure in right ventricle causes semilunar valves to open and blood travels to lungs
- heart relaxes and semilunar valves close
what is systoleand diastole?
systole is when the ventricle contracts (the pulse is felt)
diastole is when the ventricle relaxes (no pulse felt)
what is the normal systolic and diastolic pressure in a person?
120 mmHg : 80 mmHg
what is Lubb Dup?
Lubb indicates the closing of the atrioventricular valves
Dup indicates the closign of semilunar valves
what are the four parts of the intrinsic regulation of the heart?
the SA node
AV node
bundles of His
purkinje fibres
what does the SA node do?
atrial depolarisation
what does the AV node do?
atrial contraction occurs
what occurs at the AV bundle?
ventricle depolarisation
what does the purkinje fibres do?
signals spread through ventricles
