what are the main functions of the cardiovascular system? (3)
1) trasport system
- bring nutrients for metabolism -> cells and take away waste byproducts from them
2) distributes and secretes hormones
- cardiovascular transports hormones from site of production to the target cells/organs
3) homeostatic mechanism
- has a role in maintaining homeostasis and regulating body temperature
Function of heart
- muscular pump
- creates an environment by which blood can circulate through vessels around the body
What brings blood towards the heart
veins
what brings blood away from the heart
arteries
What is a driving pressure
blood pressure generated by the contraction of vesicles in the heart
What does the amount of blood flow depend on?
- resistance (inversely proportionsl)
- pressure difference (directly proportional)
- radius of blood vessels (blood flow increases with an increase in the radius cuz resistance will decrease)
What does the velocity of blood flow depend on
- total cross sectional area of blood vessels (indirectly proportional)
What is the fibrous sac which surrounds the heart
pericardium
what are the layers in the pericardium
pericardium -> epicardium -> myocardium
- there is pericardial fluid in between pericardium and epicardium
What is the function of the pericardial fluid?
- provide lubrication between the pericardium and epicardium to prevent inflammation from occuring
- also anchors heart to against diaphragm and spine to prevent excess movement
What is the pathway for deoxygenated blood?
- blood enters into the heart through the superior and inferior vena cava
- blood goes into the the RA -> tricuspid valve -> RV
- blood passes through -pulmonary valves -> pulmonary arteries -> lungs
What is the pathway for oxygenated blood?
- blood enters heart through pulmonary vein -> LA
- LA -> mitral valves -> LV -> aortic valves -> aorta + arteries which supply blood to head and arms
how does the sinoatrial node cells generate an action potential without external stimuli from nerves?
there are sodium ion channels which allow for the constant influx of sodium ions into the SA node cells -> depolarise the membrane -> generate an action potential
what are the 3 main factors which determine the rate of firing of action potential?
1) influence from autonomic system
2) initial membrane potential
3) gradient of drift towards threshold potential
