Cardiac physiology Flashcards
What is the function of the cardiovascular system?
bulk flow system to transport:
oxygen and carbon dioxide nutrients metabolites hormones
heat
explain how the cvs is flexible
the pump can vary the output
vessels can redirect blood
vessels can store blood
in the cvs output is___
in series - it is equal
beds are in parallel
most vascular beds are in parallell what does this mean?
all tissues get oxygenated blood
this allows regional redirection of blood
what is d-dimer?
D-dimer is a fibrin degradation product, a small protein fragment present in the blood after a blood clot is degraded by fibrinolysis.
which vascular beds are arranged in parallell?
head, legs, arms
which vascular beds are arranged in series
liver and gut
out of the vessel beds that work in series, which organ has its own blood supply?
liver (hepatic portal system)
how much flow og blood goes to which organs?
brain 650ml/min (13%)
heart 215ml/min (4%)
skeletal mucle 1030 (20%)
skin 430ml (9%)
kidney 950 ml/min (20%)
abdominal organs 1200ml/min (24%)
other 525 (10% **total** 5000ml/min 100%
why is it good to have blood vessel output working in parallel?
you can have redirection of blood flow to needed areas
what is total cardiac output?
5L per minute
how much oxygen comsumption occurs from which organs?
organ gets % of cardiac output oxygen consumption%
Brain 13% 18%
Skeletal muscle 20% 20%
skin 9% 2%
kidney 20% 6%
Abdominal organs 10% 14%
other 10% 14%
which organs receive more blood than it needs and why?
kidneys receive 30% of o2 but only uses 6% this is for filtration purposes more than the delivery of 02 to the tissue.
skin - for thermoregulation - get rid of heat
which organ receives less cardiac output than the o2 it consumes?
the heart
physics of pressure
flow = pressure difference / resistance
pressure difference = mean arterial pressure - central venous pressure affects all tissues
MAP and central venous pressure
mean arterial pressure is the blood leaving theheart
and the blood coming back in the the right side of the heart is the central venous pressure
calculating mean arterial pressure
double the diastolic pressure
add the sum to the systolic pressure and divide by 3.
e.g. 83/50 = 50x2+83 / 3 = MAP 61
what is resistance controlled by?
the radius of blood vessels
arterioles are important - especially in exercise e.g. gut
what is the name of the vessels taking blood away from heart?
arteries
arteries then break down into ___ and responsible for controlling __
arteries then break down into arterioles and are responsible for controlling blood flow
which vessels are responsible for exchange of nutrients, o2, co2 etc?
capillaries
blood leave the capillaries and go into ___
venuoles
what larger vessels bring deoxygenated blood back to the heart?
veins
why are venules and veins larger vessels?
they store a lot of blood
roughly how much of your blood can be stored in venules and veins?
2/3 of your blood
The cardiovascular system is a ____ system for ____
The cardiovascular system is a bulk flow system for transporting nutrients,o2,co2, heat, nutrients, metabolites around the body
the two sides of the heart are plumbed in_________
pumped in serial
Most vascular beds are plumbed in ______
parallel
___ are resistance vessels and control the _____ of blood
arterioles are resistance vessels and control the regional flow of blood
____ and __ are capacitance vessels and control the ____ of blood
venules and veins are capacitance vessels and control the fractional distribution of blood
define cardiovascular system
An organ system that conveys blood through vessels to and from all parts of the body. comprises of the: Heart Vessels and Blood
responsible for the transport of 02, C02, nutrients, metabolites, Hormones and heat
It is a closed tubular system in which the blood is propelled by a muscular heart.
describe the structure of (CVS) aorta
- elastic artery - wide lumen (low pressure), thick wall, elastic wall - damp pressure variations
The media, (middle) layer has muscle and elastic fibres, which allows the aorta to expand and contract with each heartbeat.
The adventitia, (outer) layer, provides additional support and structure to the aorta.
describe the structure of (CVS) arteries
muscular arteries = other arteries - wide lumen, strong non-elastic wall - low resistance conduit
- little resistance. muscular and ridgid.
get blood out periphery with little drop in pressure as possible
describe the structure of (CVS) arterioles
resistance vessels: narrow lumen,thick contractile walls.
control resistance and therefore flow
allow regional redirection of blood
can contract and relax to control flow
describe the structure of (CVS) capillaries
narrow (1 cell thick) lumen very thin valled for easy diffusion/gas exchange.
large surface area ratio. thin wall - small diffusion distance.
describe the structure of (CVS) Venules and veins
Capacitance vessels = wide lumen, distensible wall (absorb blood and store)
- low resistance conduit and reservoir (capacitance vessels)
allows fractional distribution of blood (stored to what is circulating). between veins and rest of circulation
QRS in chest leads v1 and v2 are usually
negative.
what is the gold standard for diagnosing angiosarcoma, what is there a risk of with this?
Biopsy
but it should be avoided due to the risk of severe bleeding.
What class of antiarrhythmics are Ca channel blockers?
Class IV
The first line of treatment for symptomatic premature atrial contractions is (drug class) .
beta blockers
During ventricular ejection, left ventricular pressure remains __ because the ventricle is contracting.
high
____ is preferred for diagnosing premature ventricular contractions and why?
Holter monitoring
because it records the cardiac electrical activity over a prolonged time.
______ number is used to predict whether blood flow will be laminar or turbulent.
Reynolds
The structure of the heart
left and right operate differently with a ventricular septum in the centre.
wall heart myocardium - thicker left than right as left builds up to bigger pressure to push blood to systemic circulation than the right which pushes to the pulmonary circulation
what is the receiving chamber of heart?
atrium
what may you also hear the aortic and pulmonary valves being called?
semi lunar
which separated left atrium from left ventricle? how many cusps?
mitral valve - 2
what valve separated right atrium from right ventricle? how many cusps?
tricuspid - 3 valves
the mitral and tricuspid semi lunar aortic and pulmonary valves are ____
passive - meaning they open and close as a result of the pressure on each side of them
the mitral valve and tricuspid valves are in large ventricles. The calves are thin. what stops them from turning inside out?
cordae tendinae
what is the purpose of cordae tendinae?
to stop the valves from inverting
as heart contracts these are shorter, so papillary muscle is present to contract at same time as heart (attached to cordae tendinae)
as the heart contracts, the length of the cordae tendinae is shorter. what helps the corinae tendinae prevent the valves from inverting?
so papillary muscle is present to contract at the same time as the heart. They contract to keep cordae tendinae appropriate length to stop valves inverting
