cardiac physiology Flashcards
Sinusoids
have large intercellular clefts that llow protein and blood cells to pass through the cells
Transcytosis
mainly for large lipid-insoluble materials, they get endocytosed, then exocytosed
hydrostatic pressure is due to
pressure water in blood plasma exerts AGAINST BLOOD VESSEL WALLS
its about 35 mmHg of mercury at the arterial end of the capillary and 16 mmHg at the venous end
IFHP is always about 0mmHg
Why dosen’t the interstitial osmotic pressur change much
because the small amount of protein that leaks from blood plasma cells do not accumulate there because it passes into lymph in lympathic capillaries, which is eventually how it returns to blood
What is the main factor that allows Frank Starling’s law of capillaries
the decrease in hydrostatic blood pressure
Difference between blood flow and blood velocity
It is the volume of blood that flows through any tissue in a given time period,
different from the blood velocity, which is the speed at which blood flows
Systolic blood pressure would be
The highest pressure in arteries during systole
Diastolic blood pressure
The lowest arterial pressure due to ventricular relaxation
Mean arterial pressure formula
Diastolic blood pressure+1/3( systolic blood pressure- diastolic blood pressure)
Total peripheral resistance
Blood vessel length-hypertension because of additional blood vessels in their adipose tissue increase their total blood vessel length
Blood viscosity-due to dehydration/polycythemia
Most of the resistance comes from physical contact with the walls of the blood vessels
what happens when you have an incompetent tricuspid valve
some of the blood goes out from ventricles, and the pressure in atria goes up, this causes a decrease in venous return caused by pressure differences
Skeletal and Lung Muscle pump
The compression of the pump is called milking,
Similarly when the diapragm expands the squeezed abdominal veins eter into the depressed thoracic veins
Chemoreceptor reflexes
part of the nervous regulation of blood pressure,
These are found in a similar place to carotid bodies and aortic bodies, and are resposible for the CV centre to increase blood pressure and beating
and getting the respiritory system for more breathing
Hypovolemic shock
when blood volume falls, kidneys secrete renin into the bloodstream,
Renin produces angiotensin, which is a potent vasoconstrictor but also helps produce aldosterone, which helps resabsorb sodium and water into kidneys
Epinephrine and Norepinephrine
force of contraction, and causes vasoconstriction of arterioles and veins in skin and abdominal organs
ADH
causes vasoconstriction and reabsorption of water into the kidney so there will be more water in bloodstream causing increased hydrostatic force
ADH
causes vasoconstriction and reabsorption of water into the kidney so there will be more water in bloodstream causing increased hydrostatic force
Triggered by increase in osmolarity of tissue fluid and volume,
should be released at a hypervolemic state or increased osmolarity of tissue fluid
Inotropic drugs
found in the interstitial fluid, this causes calcium from the interstitital fluid to flow into the myocardium, depolarising it causing contraction
parasympathetic hormones
Nitrous oxide, and Acetylcholine
Frank Starling’s law of the heart
states that stroke volume increases as end diastolic volume increases
This because as there is an increase in the volume of blood entering the heart during diastole, the ventricular myocytes are stretched
