Cardiovascular System Flashcards
Path of blood flow through cardiovascular circuit
Vena cava –> right atrium –> tricuspid valve –> right ventricle –> pulmonary valve –> pulmonary artery –> pulmonary veins –> left atrium –> mitral valve –> left ventricle –> aortic valve –> aorta
How does the heart beat on its own?
Nodal cells (pacemaker cells) have funny channels that slowly leak Na+ and K+ until depolarized enough to trigger CaVs
Sequence of depolarization
SA node –> AV node –> bundle of his –> bundle branches –> purkinje fibers
Types of extrinsic CO control
Sympathetic and parasympathetic
Describe sympathetic control on heart
NE - increases permeability to Na+ (depolarizes sooner), also increases level of intracellular Ca+ (increases contractility)
Describe parasympathetic effect on heart
ACh - activates K+ channels (hyperpolarizes), has no effect on contractility
Describe afterload and what happens when it increases
Afterload is pressure it takes to pump blood from left ventricle (systole)
If afterload increases, SV decreases
Describe preload and what happens when it increases
Preload is volume of blood the left ventricle has at the end of diastole
When increased, SV increases
Describe contractility and what happens when it increases
Contractility is the strength that the heart pumps blood out
If contractility increases, SV and BP increase
What is the velocity of blood flow equation and what does it mean when blood reaches the capillaries?
V= Q/A
In capillaries, A is increased dramatically so velocity decreases
What are the 3 mechanisms of autoregulation
Metabolic Control - lactic acid, K+, H+, prostaglandins, NO, inflammatory chemicals
Myogenic Control - reactive hyperemia
Long Term Control - angiogenesis
Describe lymphatic system - properties and purpose
Highly permeable, one-way capillaries from capillaries to vena cava
Characteristics similar to veins
