CARDIO Flashcards
what is hemodynamics
study of blood flow
what does hemodynamics look at
relationship b w
- blood flow
- blood pressure
- resistance to blood flow
what determines blood flow
- pressure difference bw 2 diff points
2. resistance to blood flow
what is blood flow formula
blood flow = (pressure diff bw 2 diff points) / resistance to blood flow
what does not determine blood flow
absolute pressure at any given point
what is resistance to blood flow
how difficult it is for blood to move bw 2 diff points at any given pressure
how does blood flow
- down pressure gradient
- from region of higher pressure to region of lower pressure
what provides driving force for blood flow
pressure diff
what is required for blood to flow
- pressure diff needs to overcome resistance to blood flow
- delta P > R
what is hydrostatic pressure or “pressure”
pressure that vol of blood exerts on walls of blood vessels that contain it
why can’t resistance be measured
determined by several factors
what factors determine resistance to blood flow
- viscosity of blood
- length of blood vessel
- diameter of blood vessel
what is viscosity
friction bw molecules of flowing fluid
what is result of blood become more viscous
- more friction bw molecules of flowing fluid
- greater resistance to blood flow
what does greater contact bw walls and blood result in
- greater friction
- greater resistance to blood flow
what do vessels with longer length produce
- greater friction
- greater resistance to blood flow
what do vessels with shorter length produce
- less friction
- less resistance to blood flow
what does constriction of blood vessel result in
decrease diameter of blood vessel
what does dilation of blood vessel result in
increase diameter of blood vessel
how does blood travel through blood vessels
concentric layers
what do vessels w smaller diameter produce
- greater friction
- greater resistance to blood flow
why do blood vessels with smaller diameter produce greater friction + greater resistance to flow
- less concentric layers
- more blood in contact w blood vessel walls
what do vessels w larger diameter produce
- less friction
- less resistance to blood flow
why do blood vessels with smaller diameter produce less friction + less resistance to blood flow
- more concentric layers
- less blood in contact w blood vessel walls
what does poiseuille’s equation define
relationship bw
- viscosity
- blood vessel length
- blood vessel diameter / radius
when does poiseuille’s equation apply
laminar flow
what is laminar flow
flow that is
a. slow
b. regular
what factor has greatest effect on resistance
diameter / radius
what does small change in vessel diameter result in
large change in resistance
what is poiseuille’s equation
resistance = (8 x viscosity x length of vessel) / (pi x radius of vessel to the power of 4)
what are functions of cardiovascular system (5)
- deliver oxygen and nutrients
- remove waste
- allow fast chemical signalling to cells by circulating hormones or transmitters
- thermoregulation
- mediate inflammatory and host response
3 components of cardiovascular system
- heart
- blood vessels
- blood
what can vessels be divided into
- arteries
- arterioles
- capillaries
- venules
- veins
what kind of system is cardiovascular system
closed system
what are 4 chambers of heart
- 2 atria
- 2 ventricles
how are walls of atria characterized
- thin
- low pressure
how are walls of ventricles characterized
- thick
- high pressure
what is function of atria
receive blood returning to heart
what are 2 great veins
- superior vena cava
2. inferior vena cava
what are 2 great arteries
- aorta
2. pulmonary trunk
what does L side of heart pump
highly ox blood
what does R side of heart pump
highly deox blood
what is function of septa
prevent mixing of ox and deox blood
what separates L and R atria
interatrial septum
what separates L and T ventricles
interventricular septum
where does L side of heart pump its blood
- ox
- systemic circuit
where does R side of heart pump its blood
- deox
- pulmonary circuit
what kind of blood enters lungs
de ox
what happens to blood that enter lungs
oxygen diffuses from lung tissue to blood
what kind of blood leaves lungs
ox
what kind of blood enters body tissues
ox
what happens to blood that enter body tissues
oxygen diffuses from blood to interstitial fluid
what kind of blood leaves body tissues
de ox
what is pathway of blood
- L atrium receives ox blood from pulmonary vein
- L ventricle pumps ox blood to systemic circuit through aorta
- ox blood becomes deox blood
- R atrium receives deox blood from from superior + inferior vena cava
- R ventricle pumps deox blood to pulmonary circut through pulmonary artery
- deoc blood becomes ox blood
- L atrium receives ox blood from pulmonary vein
where does each circuit start and end
heart
how does blood flow in cardiovascular system
in series / in sequence
how does blood flow occur in systemic circuit
in parallel
what does it mean for blood flow to occur in parallel in systemic circuit
separate arteries supply each organ
what is exception to parallel blood flow
liver
what does parallel blood flow allow
regulation of blood flow to each region
- increasing blood flow when necessary
- decreasing blood flow when necessary
what is pericardium
sac surrounding
a. heart
b. roots of great blood vessels
what are great blood vessels
- aorta
- pulmonary trunk
- vena cava
PERICARDIAL STRUCTURE how many layers of pericardium
3
PERICARDIAL STRUCTURE what are 3 layers of pericardium
- fibrous pericardium
- serous pericardium
- visceral pericardium
PERICARDIAL STRUCTURE what are functions of fibrous pericardium
- protection
- stabilize heart in thoracic cavity
- prevent over filling of heart
PERICARDIAL STRUCTURE how does fibrous pericardium stabilize heart in thoracic cavity
attaches to structures in chest
PERICARDIAL STRUCTURE how does fibrous pericardium precent overfilling
does not stretch readily
PERICARDIAL STRUCTURE what makes up serous pericardium
- parietal
2. visceral
PERICARDIAL STRUCTURE what is parietal layer
layer composed of cells that secrete fluid
PERICARDIAL STRUCTURE what separates parietal pericardium from visceral pericardium
pericardial cavity
PERICARDIAL STRUCTURE what is inner most layer
visceral pericardium
PERICARDIAL STRUCTURE what is visceral pericardium part of
heart wall
PERICARDIAL STRUCTURE what is the function of pericardial fluid secreted by serous layer
reduce friction bw pericardial mems
what does thickness of L ventricle allow
generation of higher pressure during contraction
what does generation of higher pressure during contraction allow
allows for blood to be pumped to entire systemic circuit
HEART WALL what are components of heart wall
- epicardium
- myocardium
- endocardium
HEART WALL what is epicardium
where visceral pericardium comes into contact w heart wall
HEART WALL what does epicardium consist of
1 layer of simple squamous epithelium
HEART WALL what is attached to 1 layer of simple squamous epithelium
layer of CT (myocardium)
HEART WALL what is myocardium
muscular wall of heart
HEART WALL what does myocardium contain
- myocytes
- nerves
- blood vessels
HEART WALL what does endocardium line
- heart cavities
2. heart valves
HEART WALL what is endocardium
thin layer of epithelium
HEART WALL what does endothelium provide
smooth surface for blood to flow over
HEART WALL how does heart wall differ bw atria and ventricles
ventricles have thicker myocardium
what are gap junctions important for
spreading AP through atria and ventricles
